preface

about the book

contents

List of Figures

about the authors

List of Abbreviations

1 introduction

j. tosun et al.

2 conceptual framework

3 united states

j. tosun et al

4 canada

5 germany

6 spain

7 united kingdom

8 comparative assessment

9 conclusion

Index^1

index

PALGRAVE STUDIES IN
SUB-NATIONAL GOVERNANCE

Subnational Climate Leadership Dynamics Among Under2 Coalition Members
Jale Tosun · Simon Bulian Alfie Gaffney · Joan Enguer Emiliano Levario Saad
Palgrave Studies in Sub-National Governance
Series Editors
Linze Schaap
Tilburg University, Tilburg, The Netherlands
Jochen Franzke
University of Potsdam, Potsdam, Germany
Hanna Vakkala
Faculty of Social Sciences
University of Lapland, Rovaniemi, Finland
Filipe Teles
University of Aveiro, Aveiro, Portugal
This series explores the formal organisation of sub-national government and democracy on the one hand, and the necessities and practices of regions and cities on the other hand. In monographs, edited volumes and Palgrave Pivots, the series will consider the future of territorial governance and of territory-based democracy; the impact of hybrid forms of territorial government and functional governance on the traditional institutions of government and representative democracy and on public values; what improvements are possible and effective in local and regional democracy; and, what framework conditions can be developed to encourage minority groups to participate in urban decision-making. Books in the series will also examine ways of governance, from ‘network governance’ to ‘triple helix governance’, from ‘quadruple’ governance to the potential of ‘multiple helix’ governance. The series will also focus on societal issues, for instance global warming and sustainability, energy transition, economic growth, labour market, urban and regional development, immigration and integration, and transport, as well as on adaptation and learning in sub-national government. The series favours comparative studies, and especially volumes that compare international trends, themes, and developments, preferably with an interdisciplinary angle. Country-by-country comparisons may also be included in this series, provided that they contain solid comparative analyses.
Jale Tosun • Simon Bulian •
Alfie Gaffney • Joan Enguer •
Emiliano Levario Saad
Subnational Climate
Leadership Dynamics
Among Under2
Coalition Members

Jale Tosun
Institute of Political Science
Heidelberg University
Heidelberg, Germany
Department of Political Science
University of Oslo, Oslo, Norway
Alfie Gaffney
School of Environmental Sciences
University of East Anglia, Norwich, UK
Emiliano Levario Saad
Institute of Political Science
Heidelberg University
Heidelberg, Germany

Simon Bulian
Institute of Political Science
Heidelberg University
Heidelberg, Germany
Joan Enguer
Department of Constitutional Law and
Political Science
University of Valencia
Valencia, Spain

ISSN 2523-8248	ISSN 2523-8256 (electronic)
Palgrave Studies in Sub-National Governance
ISBN 978-3-032-12609-2	ISBN 978-3-032-12610-8 (eBook)
https://doi.org/10.1007/978-3-032-12610-8
This work was supported by University of East Anglia.
© The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2026. This book is an open access publication.
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Preface
Subnational actors worldwide are increasingly stepping forward to fill governance gaps left by national governments in addressing climate change. This trend reflects both the urgent need for climate action and the unique positioning of, in particular, subnational governments, which are simultaneously close enough to citizens to understand local impacts and large enough to achieve meaningful carbon emissions reductions. The proliferation of transnational networks connecting these subnational actors has created forms of climate governance that operate across traditional jurisdictional boundaries. These networks facilitate knowledge sharing, coordinate policy approaches, and amplify the collective voice of committed subnational governments on the international stage.
Among the most prominent of these networks is the Under2 Coalition, convened by Climate Group, which serves as its secretariat. It is the largest existing network of states and regions committed to achieving net-zero emissions by 2050 at the latest. This book examines the Under2 Coalition as an exemplary organization facilitating transnational climate governance through detailed analysis of climate policy actions taken by some of its founding members and subnational actors that joined later from North American and European countries.
It builds on research conducted through the collaborative project between the University of East Anglia, United Kingdom, and Heidelberg University, Germany: “Deep Decarbonization: The Democratic Challenge of Navigating Governance Traps” (DeepDCarb), generously funded by a European Research Council Advanced Grant (Grant Agreement Number: 882601). DeepDCarb funding also enabled open access
publication of this book, ensuring broad accessibility for academic and practitioner audiences, for which we are grateful.
Joan Enguer and Simon Bulian led the subnational-level data collection, which formed a key component of Joan Enguer’s doctoral thesis. All DeepDCarb members engaged with these insights, including Andrew Jordan, the project leader, Irene Lorenzoni, the project co-leader, and the project team members Lucas Geese, Christin Heinz-Fischer, John Kenny, and Chantal Sullivan- Thomsett. Additional US state-level climate policy data collection was facilitated by the “Accelerating Climate Action and the State: Getting to Net Zero” (ACCELZ) project for the researcher position of Emiliano Levario Saad, funded by the Research Council of Norway (Grant Agreement Number: 335073) and led by Elin Lerum Boasson at the University of Oslo, Norway. Jale Tosun further acknowledges funding from the collaborative research project “Rethinking Co-creation of Digital and Environmental Policy in Systems of Multilevel Governance” (RECODE MLG; funded by the European Commission via Grant Agreement ID: 101177521). Finally, Alfie Gaffney’s involvement was generously funded by the Leverhulme Trust’s Critical Decade for Climate Change doctoral study program.
In addition to the feedback received from DeepDCarb and ACCELZ colleagues, we thank Paul Böhringer, Laurence Crumbie, Alexander Helm, and Thore Wann for their assistance in finalizing the manuscript. We are further grateful for valuable research assistance by Jill Werner, Gideon Wessel, and Nora Zabel.
We hope this book will generate new insights for both academics and practitioners working on climate governance, while fostering new research collaborations that advance our understanding of policy-based climate action by subnational actors.

Heidelberg, Germany Heidelberg, Germany Heidelberg, Germany
Valencia, Spain
Olso, Narway
Heidelberg, Germany
October 2025

Jale Tosun Simon Bulian Alfie Gaffney Joan Enguer
Emiliano Levario Saad

Competing Interests The authors have no competing interests to declare that are relevant to the content of this manuscript.
About the Book
This book examines climate policy effort among subnational governments participating in the Under2 Coalition (U2C), a transnational climate initiative founded in 2015. The U2C emerged during a transformative period in climate governance following the perceived failure of the 15th Conference of the Parties to the United Nations (UN) Framework Convention on Climate Change in 2009, which sparked a “Cambrian explosion” of alternative cooperation forms beyond traditional UN frameworks. Founded through collaboration between California and Baden- Württemberg, the U2C represents a unique case of subnational climate leadership. Members commit to limiting global warming to 1.5°C and achieving net-zero emissions by 2050, making their commitments measurable and comparable.
The central research question investigates whether U2C founding members demonstrate greater climate policy effort compared to early joiners (2015–2016) and later joiners (post-2016), and whether performance differences persist over time.
The book’s analytical framework builds on Liefferink and Wurzel’s conceptualization of “leadership” and “followership” dynamics in climate governance. Climate leaders are characterized by ambitious action exceeding minimum requirements and serving as models for others, while followers adopt more cautious approaches aligned with proven models. The authors interpret higher climate policy effort as an indication of climate leadership.
The empirical analysis focuses on subnational governments in five countries that played influential roles in founding and developing the U2C: Canada, Germany, Spain, the United Kingdom (UK), and the United States. Each country represents different constitutional arrangements for climate policy, from Germany’s constrained concurrent legislation principle to the United States’ highly decentralized federal structure granting states broad regulatory powers.
The book is organized into nine chapters, with the empirical core consisting of five detailed case studies. The most extensive analysis examines the United States, comparing four founding states (California, Oregon, Vermont, and Washington) with 12 later-joining states. Similar comparative analyses are conducted for Canadian provinces, German states, Spanish autonomous communities, and UK constituent nations.
The study makes three key contributions to the climate governance literature. First, it systematically demonstrates how climate policy effort and leadership dynamics have evolved within the U2C framework. Second, it provides genuinely comparative insights across two dimensions—com- paring different membership categories within countries and across nations. Third, it offers a replicable methodological template for expanding this research approach to other contexts.
By examining quantifiable indicators including policies, policy instruments, and greenhouse gas emissions reduction targets, the book provides valuable insights into how multilevel climate governance can be strengthened and sustained over time, bridging theory and practice in understanding subnational climate action.
Contents
1		Introduction	1
Under2 Coalition	4
Founding Phase	4
Expansion over Time	6
Mission and Governance Structure	9
Conceptual and Research Framework	10
Organization of the Book	12
Contributions to the Literature	12
References	14
2		Conceptual Framework	19
Multilevel Climate Governance	21
Leadership in Climate Governance	23
Leadership over Time	26
Strengthening Effects	26
Weakening Effects	27
Interaction Between Factors	28
Propositions	28
Conclusion	31
References	32
3		United States	37
Introduction	38
Founding Members	39
California	39
Oregon	40
Vermont	41
Washington	42
Early Joiners	43
Connecticut	43
Massachusetts	44
Minnesota	45
New Hampshire	46
New York	47
Rhode Island	48
Late Joiners	49
Colorado	49
Hawaii	50
Maine	50
Maryland	51
Nevada	52
New Jersey	52
Virginia	53
Comparative Analysis	54
Policies	54
Policy Instruments	58
Targets	62
Leadership	65
Conclusion	66
References	67
4		Canada	71
Introduction	72
Founding Members	72
British Columbia	72
Ontario	73
Early Joiner	74
Québec	74
Later Joiner	75
Northwest Territories	75
Comparative Analysis	76
Policies	76
Policy Instruments	81
Targets	84
Leadership	85
Conclusion	87
References	88
5		Germany	93
Introduction	94
Founding Member	95
Baden-Württemberg	95
Early Joiners	95
Bavaria	95
Hesse	96
North Rhine-Westphalia	96
Schleswig-Holstein	96
Thuringia	96
Later Joiners	97
Lower Saxony	97
Rhineland-Palatinate	97
Comparative Analysis	97
Policies	97
Policy Instruments	104
Targets	108
Leadership	109
Conclusion	111
References	112
6		Spain	115
Introduction	116
Founding Member	117
Catalonia	117
Early Joiners	118
Basque Country	118
Foral Community of Navarre	118
Later Joiners	119
Andalusia	119
Community of Madrid	120
Galicia	120
Comparative Analysis	121
Policies	121
Policy Instruments	125
Targets	128
Leadership	130
Conclusion	132
References	134
7		United Kingdom	137
Introduction	138
Founding Member	139
Wales	139
Early Joiner	140
Scotland	140
Later Joiners	141
Northern Ireland	141
Isle of Man	141
Comparative Analysis	142
Policies	142
Policy Instruments	145
Targets	149
Leadership	152
Conclusion	154
References	155
8		Comparative Assessment	159
Introduction	160
United States	160
Founding Members	160
Early Joiners	161
Later Joiners	162
Canada	163
Founding Members	163
Early Joiner	163
Later Joiner	164
Germany	164
Founding Member	164
Early Joiners	165
Later Joiners	165

Spain	166
Founding Member	166
Early Joiners	166
Later Joiners	167
United Kingdom	168
Founding Member	168
Early Joiner	169
Later Joiners	169
Cross-Regional Patterns and Insights	170
Temporal Patterns and Membership Dynamics	171
Conclusion	173
9		Conclusion	175
Introduction	176
Main Findings	176
Assessment of the Propositions	176
Types of Climate Leadership	179
Followership	180
Limitations	181
Future Research Directions	182
Conclusion	184

Index

References	185
187

Fig. 1.1

Countries with Under2 coalition signatories in 2015. Note:
Colors denote a country’s share of subnational entities that have joined U2C	6

Fig. 1.2 | Countries with U2C signatories in 2024. Note: Colors denote a country’s share of subnational entities that have joined U2C	8
Fig. 3.1 | Adoption of climate laws, plans, programs, and regulations by founding signatories	54
Fig. 3.2 | Adoption of climate laws, plans, programs, and regulations by early-j oining signatories	55
Fig. 3.3 | Adoption of climate laws, plans, programs, and regulations by later-j oining signatories	57
Fig. 3.4 | Policy instruments to reduce regional GHG emissions by founding signatories	58
Fig. 3.5 | Policy instruments to reduce regional GHG emissions by early-joining signatories	60
Fig. 3.6 | Policy instruments to reduce regional GHG emissions by later-joining signatories	61
Fig. 3.7 | Greenhouse gas emissions reduction targets by founding signatories	62
Fig. 3.8 | Greenhouse gas emissions reduction targets by early-joining signatories	63
Fig. 3.9 | Greenhouse gas emissions reduction targets by later-joining signatories	64

Fig. 4.1
Fig. 4.2
Fig. 4.3

Adoption of climate laws and plans 77 Policy instruments to reduce regional GHG emissions 81 Greenhouse gas emissions reduction targets 85

Fig. 5.1 | Adoption of climate policies | 98
Fig. 5.2 | Policy instruments to reduce regional GHG emissions | 105
Fig. 5.3 | GHG emissions reduction targets | 108
Fig. 6.1 | Adoption of climate policies | 121
Fig. 6.2 | Policy instruments to reduce regional GHG emissions | 126
Fig. 6.3 | Greenhouse gas emissions reduction targets | 128
Fig. 7.1 | Adoption of climate laws and plans | 143
Fig. 7.2 | Policy instruments to reduce regional GHG emissions | 146
Fig. 7.3 | Greenhouse gas emissions reduction targets | 149

About the Authors
Simon Bulian is a postdoctoral researcher at the Institute of Political Science at Heidelberg University. He studies the politics of environmental issues, with a special focus on public policy, determinants of environmental policy-making, and individual environmental attitudes. He is part of the ERC-funded collaborative project DeepDCarb (“Deep Decarbonization: The Democratic Challenge of Navigating Governance Traps”) on climate politics.
Joan Enguer is a postdoctoral researcher in the Department of Constitutional Law and Political Science at the University of Valencia, working on the Horizon- funded project Blue Green Governance. In December 2024, he completed his PhD at Heidelberg University, as part of the ERC-funded project DeepDCarb. He is an associate editor of the journal Frontiers in Political Science and his current research focuses on climate and environmental governance.
Alfie Gaffney is a Critical Decade for Climate Change Leverhulme Doctoral Scholar in Political Science at the Tyndall Centre for Climate Change Research & School of Environmental Sciences, University of East Anglia. He researches the role of local climate policy entrepreneurship in stepping up local climate ambition across (un)favorable contexts. He is also an affiliate member of the Centre for Climate Change and Social Transformations (CAST).
Emiliano Levario Saad is a PhD candidate in Political Science at Heidelberg University, Germany. He works as a research assistant in the project “Accelerating Climate Action and the State: Getting to Net Zero” (ACCELZ) and also collaborates in the project DeepDCarb. He studies climate governance with a special focus on The Americas.
Jale Tosun is Professor of Political Science at the University of Heidelberg and adjunct professor at the University of Oslo in the frame of the ACCELZ project funded by the Research Council of Norway. She is the editor-in-chief of the Nature Portfolio Journal Climate Action and associate editor of Policy Sciences. She is one of the coordinators of the Erasmus Mundus Joint Master’s Program in European Environmental Economics and Policy (M3EP).
CAA | Clean Air Act (of California)
CCC | Climate Change Committee (UK)
CDU | Christian Democratic Union of Germany
CES | Clean Energy Standard
COP | Conference of the Parties
CPP | Climate Pathway Project
ENCORE | Environment Conference of the Regions of Europe
EU | European Union
EV | Electric vehicle
GEGEA | Green Energy and Green Economy Act (Ontario, 2009)
GHG | Greenhouse gas
ICLEI | International Council for Local Environmental Initiatives
IPCC | Intergovernmental Panel on Climate Change
NEG-ECP | New England Governors and Eastern Canadian Premiers
LEV | Low-Emissions Vehicle
LNG | Liquid Natural Gas
MLG | Multilevel governance
MoU | Memorandum of Understanding
NRG4SD | Network of Regional Governments for Sustainable Development
PCF | Pan-Canadian Framework on Clean Growth and Climate Change
RGGI | Regional Greenhouse Gas Initiative
SDG | Sustainable Development Goals
SPD | Social Democratic Party of Germany
U2C | Under2 Coalition
UK | United Kingdom

UN UNFCCC
US
ZEV

United Nations
United Nations Framework Convention on Climate Change
United States
Zero Emissions Vehicle

CHAPTER 1	
Introduction
Abstract This introductory chapter formulates the overarching research interest of the book: the examination of climate policy effort among subnational governments in the Under2 Coalition, a transnational network founded in 2015 by regional jurisdictions committed to limiting global warming to 1.5°C. The central research question asks whether Under2 Coalition founding members demonstrate greater and more sustained climate policy effort compared to early joiners (2015–2016) and later joiners (post-2016) within their respective national contexts. Drawing on the conceptual framework of climate leadership and followership, the study conducts systematic comparative analysis across five countries: the United States, Canada, Germany, Spain, and the UK. The analysis focuses on quantifiable indicators including policies, policy instruments, and greenhouse gas emissions reduction targets over the decade since the Under2 Coalition’s establishment. The research contributes to understanding how subnational climate leadership manifests itself in multilevel governance systems and provides a replicable methodological template for examining climate policy dynamics in the members of transnational networks beyond European and North American contexts.
Keywords Climate leadership • Multilevel governance • Subnational climate governance • Transnational networks • Under2 Coalition
© The Author(s) 2026	1
J. Tosun et al., Subnational Climate Leadership Dynamics Among
Under2 Coalition Members, Palgrave Studies in Sub-National Governance, https://doi.org/10.1007/978-3-032-12610-8_1
This book focuses on climate policies adopted by subnational governments in multilevel polities that have joined the Under2 Coalition (U2C), founded in 2015. Over the past 20 years, subnational governments have become recognized as key players in addressing climate change (Dubash, 2021), either independently or by joining transnational organizations like U2C.
We seek to understand whether founding members of U2C (i.e., those who signed the founding document) demonstrate greater climate policy effort compared to early joiners (i.e., those who became parties in 2015–2016) and later joiners (i.e., those who became parties after 2016). We define policy effort as the level of activity and ambition in climate action. Additionally, we examine whether such performance differences, if observable, are sustained over the decade since the founding of U2C.
To motivate our research perspective and position it within the existing literature, we first briefly review developments in international climate cooperation, as this context—along with national-level dynamics—shapes the environment in which subnational governments operate.
The foundation of climate governance was laid in 1988 when the United Nations (UN) recognized climate change as an issue requiring international cooperation and established the Intergovernmental Panel on Climate Change (IPCC) as the authoritative body for providing scientific information on climate change (Hermansen et al., 2023). At its Conference on Environment and Development in 1992, the UN launched a process for negotiating an international agreement to limit dangerous anthropogenic climate change. The resulting international treaty between the participating countries was the UN Framework Convention on Climate Change (UNFCCC), which established the basic legal framework and principles for international climate cooperation. It was signed throughout June 1992 and 1993 and became effective on 21 May 1994, marking the beginning of formal multilateral climate governance (Kuyper et al., 2018).
The next milestone in UN-led international climate cooperation was the negotiation of the Kyoto Protocol, which extended the UNFCCC and committed the signatory states to legally binding targets for reducing greenhouse gas (GHG) emissions. The Protocol represented the first attempt to establish quantified GHG emissions reduction commitments for developed countries. The Kyoto Protocol was signed in 1997 but only entered into force on 16 February 2005, following Russia’s ratification (Henry & Sundstrom, 2007), with the first commitment period starting in 2008 and ending in 2012.
A governance framework for climate change mitigation beyond 2012 should have been negotiated and agreed upon at the 15th session of the Conference of the Parties (COP 15) to the UNFCCC held in 2009. COP 15 was widely anticipated as a critical juncture for global climate governance, with expectations running high for a comprehensive post-Kyoto agreement. However, the parties were unable to reach consensus on a binding agreement, instead producing only the non-binding Copenhagen Accord—named after the host city of COP 15. This outcome drew significant criticism from parties that had advocated for a more ambitious legally binding treaty, as well as from numerous non-state and subnational actors (Dimitrov, 2010).
The perceived failure of COP 15 is widely regarded as having produced a “Cambrian explosion” of alternative forms of cooperation beyond the UNFCCC; these are based on transnational cooperation rather than traditional international cooperation, making climate governance more complex (Keohane & Victor, 2011) and polycentric (E. Ostrom, 2010, 2011; V. Ostrom et al., 1961; Jordan et al., 2018, 2015; Jordan & Huitema, 2014; Tobin et al., 2024).
By the signing of the Paris Agreement in 2015 at the latest, subnational governments had emerged as a relevant force in advancing climate action (Bäckstrand et al., 2017), demonstrating leadership through policy innovation, early adoption of ambitious GHG emissions reduction targets, and implementation of concrete climate policy measures (Francesco et al., 2020). These initiatives include transnational networks such as the Global Covenant of Mayors (Kona et al., 2021), C40 Cities Climate Leadership Group (Heikkinen et al., 2019), International Council for Local Environmental Initiatives (ICLEI) (Francesco et al., 2020), and U2C (Unger & Thielges, 2021).
While all these initiatives possess interesting features and studying each can provide important insights into climate governance, U2C stands out for several reasons. First, it is composed of governments operating between the national and local levels, thus acting on behalf of larger geographical and jurisdictional units. Second, U2C has concrete, measurable commitments centered on the specific target of limiting global temperature rise to under 1.5 degrees Celsius, which enables systematic assessment of whether members are actually delivering on their stated ambitions. Third, the way U2C was established makes it straightforward to identify founding members and compare their climate policy profiles to those who joined later, which makes it an analytically rewarding case to study.
This chapter provides background information on U2C, its origins, structure, and significance within the broader landscape of transnational climate governance. It further outlines the central research interest of this book— examining whether founding members of U2C have demonstrated superior climate policy effort compared to other member subnational governments within their respective national contexts—and sketches out the analytical framework and structure that will guide the subsequent empirical investigation.
Under2 Coalition
Founding Phase
While U2C emerged during a particularly active period of climate institution- building, it stands out for originating from the innovative initiative of subnational rather than national governments. The coalition was formally founded in May 2015 in the run-up to COP21, building on a collaboration between the US State of California and the German State of Baden-Württemberg, two subnational jurisdictions committed to ambitious climate action (Galarraga et al., 2017). Both states already had in place a climate protection law and several policies to cut GHG emissions in specific sectors, including energy generation, energy use in buildings, and transportation (Allison et al., 2016; Jacob & Kannen, 2015). Preexisting cooperation between the two states, such as through the Transatlantic Climate Bridge initiative launched in 2008, led government officials to recognize the value in creating a formal coalition of subnational actors to stimulate concerted subnational climate action (Thielges, 2019). The formal foundation of U2C rests upon a Memorandum of Understanding (MoU), which serves as the primary governing document while remaining non-legally binding in nature.

The information presented in this section is based on the sources cited as well as information provided on the following websites: https://www.theclimategroup.org/under2-coali- tion (The Climate Group) and https://um.baden-wuerttemberg.de/de/klima-energie/ klimaschutz/internationaler-klimaschutz/under2-coalition (Ministry for the Environment, Climate and Energy Sector auf die State of Baden-Württemberg).

Another ten subnational governments joined the initiative and, together with California and Baden-Württemberg, co-founded U2C in May 2015. Founding U2C reinforced pre-exisiting partnerships among these governments. The Brazilian state of Acre was already a subnational leader in curbing deforestation and forest degradation at that time (Climate Focus, 2013). Prior to co-founding U2C, Acre had partnered with California as part of the Reducing Emissions from Deforestation and Forest Degradation Offset Working Group (Gueiros et al., 2023).
Baja California and Jalisco were the two Mexican states that co-founded U2C. Jalisco has long been one of Mexico’s most deforested states (García- Jiménez & Vargas-Rodriguez, 2021; Cullenward, 2017). Unlike Acre in Brazil, it was not a leader in counteracting deforestation at the time of U2C’s inception, but began taking policy action afterwards. However, like Acre, it had already been collaborating with California within the framework of the Governors’ Climate & Forests Task Force (GCF).
Baja California in Mexico and the US state of California share a border and had already established close ties before co-founding U2C. They had collaborated on renewable energy projects (particularly wind power) and other climate initiatives as part of an agreement between California and the Mexican Ministry of Environment and Natural Resources, which can be seen as a direct precursor to Baja California’s involvement in U2C.
British Columbia and Ontario were the two Canadian co-founding members (see also Chap. 4). They had pre-existing ties with California through their membership in the Pacific Coast Collaborative (PCC), a regional cooperation on energy and environmental matters, and the Western Climate Initiative (WCI), a regional collaboration launched in 2007 by US states and Canadian provinces to design a multi-jurisdictional cap-and-trade program (Cullenward, 2017; Houle et al., 2015).
Oregon, Vermont, and Washington were the other three co-founding states from the United States (see also Chap. 3). Oregon was one of the early movers in US climate action and had already forged climate partnerships with California, most notably as a co-founding member of both the PCC and the WCI. Similarly, Vermont had been a member of the Regional Greenhouse Gas Initiative (RGGI), implementing a cap-and-trade system for the power sector together with other northeastern US states (Yan, 2021). As a signatory to the WCI, it also had prior exchanges with California on climate policy. Finally, Washington had already-established ambitious statutory GHG emissions reduction targets by 2008 and cofounded both the PCC and the WCI in collaboration with California and Oregon (Cullenward, 2017).
The Spanish autonomous region of Catalonia and Wales were the European co-founding members. Both were climate leaders well before U2C’s inception (see also Chaps. 6 and 7). They had also collaborated with Baden-Württemberg and California through pre-existing partnerships, including the Network of Regional Governments for Sustainable Development (NRG4SD) and the Climate Group’s States & Regions Alliance (CGSRA). Founded in 2005, the latter served as a key pre- Under2 forum that enabled Catalonia to collaborate with the other European members on subnational commitments, climate target benchmarking, and joint advocacy at COPs (Happaerts et al., 2010).
Expansion over Time
Numerous subnational governments joined U2C at a series of events throughout 2015, including the World Summit on Climate and Territories in the Rhône-Alpes Region of France, the Climate Week in New York City, and the World Expo hosted by Milan, Italy. Figure 1.1 visualizes the global distribution of U2C signatories by the end of 2015.

Fig. 1.1 Countries with Under2 coalition signatories in 2015. Note: Colors denote a country’s percentage share of subnational entities that have joined U2C
In North America, the Canadian province of Québec joined, having been part of the WCI and having already formally linked its cap-and-trade system with California in 2014 (Houle et al., 2015). In the United States, Connecticut, Massachusetts, Minnesota, New Hampshire, New York State, and Rhode Island joined the four founding US states. All of these new members, except for Minnesota, were already part of the regional RGGI of the northeastern US states.
In Latin America, the Brazilian states of São Paulo and Mato Grosso joined, along with Mexico State from Mexico. The Ucayali region was the first to join from Peru. Located in the Peruvian Amazon, it shares a border with the U2C co-founding state of Acre in Brazil. Ucayali had also been a member of GCF and was therefore already connected with California as well as with the Brazilian and Mexican co-founding states of U2C.
In Europe, Baden-Württemberg was joined by the German states of Bavaria, Hesse, North Rhine-Westphalia, Schleswig-Holstein, and Thuringia. Similarly, the Basque Country and the Foral Community of Navarre joined Catalonia in Spain. Additional regions joined from France (Aquitaine, Brittany, Occitanie, Poitou-Charentes, and Rhône-Alpes), Italy (Emilia-Romagna, Lombardy, Piedmont, and Sardinia), the Netherlands (Drenthe), Portugal (Azores andMadeira), and Sweden (Jämtland and Härjedalen).
A smaller number of subnational actors joined U2C from Asia and Oceania. South Australia was the first Australian state to participate. The Chinese provinces of Jiangsu and Sichuan signed the U2C MoU, building on an evolution of climate partnerships between California and Chinese provinces dating back to the 1970s (Jin, 2025). The Japanese prefecture of Gifu also joined, having previously been a member of ICLEI. Finally, the Kathmandu Valley in Nepal signed the U2C MoU in 2015 as well.
The coalition has grown steadily since 2015. A larger number of new signatories joined U2C in 2021 in the run-up to COP26 in Glasgow and in 2022 in the run-up to COP27 in Sharm el-Sheikh. Remarkably, all regions of Morocco became members of the network at the conference.
By 2024, around 10% of subnational entities had signed the U2C MoU, making it a global network spanning all five major continental regions. Figure 1.2 shows the distribution of the more than 183 signatories across the globe in 2024.
Some founding members of U2C were especially successful in attracting new signatories within their own countries. Brazil stands out, with nearly 75% of Brazilian states following Acre to join the network. Many of

Fig. 1.2 Countries with U2C signatories in 2024. Note: Colors denote a country’s percentage share of subnational entities that have joined U2C

these joined during Jair Bolsonaro’s presidency between 2019 and 2023, when climate protection was weakened at the federal level and subnational climate action became even more urgent (Milani et al., 2025). The Climate Pathway Project (CPP) was initiated during this period, empowering the subnational governments of Amazonas, Mato Grosso, and São Paulo to develop policy pathways for long-term emissions reductions under U2C guidance. Similarly, 19 Mexican states—approximately two-thirds of all Mexican states—are now U2C members. Three of these (Quintana Roo, Querétaro, and Madre de Dios) have also participated in the CPP, developing policy pathways for long-term GHG emissions reduction.
In the United States, 17 states signed the Under2 MOU, representing 33% of all US states. All are “blue” states with historically Democratic dominance, reflecting the bipartisan polarization of climate action in the United States. In Canada, only the Northwest Territories joined after 2015, meaning four Canadian subnational entities (33%) are U2C members today. In Europe, 80% of UK subnational governments participate in the coalition, as Northern Ireland and the Isle of Man joined in 2021. In Germany, seven additional states joined Baden-Württemberg, totaling 50% of the country’s states. Finally, Spanish signatories increased to six, representing 31% of Spanish subnational entities.
Some non-founding countries also witnessed a significant rise in new signatories to the Under2 MOU. Australia has a strong legacy of subnational climate action, contrasting with a long period of national-level inaction (Christoff & Eckersley, 2021); indeed, three-quarters of Australian states are U2C members today. France is another non-founding country that saw numerous regions join the coalition, with more than half of its 13 regions having signed the MoU (54% of subnational governments).
Mission and Governance Structure
The signatories of the MoU commit themselves to limiting global warming to no more than 1.5 degrees Celsius above preindustrial average temperatures. Additionally, U2C members have pledged to achieve net-zero greenhouse gas emissions by 2050, with many jurisdictions striving to achieve this even earlier.

The UNFCCC states its explicit intention to “pursue efforts to limit the [global] temperature increase to 1.5°C above pre-industrial levels” and the IPCC was invited to “provide a special report in 2018 on the impacts of global warming of 1.5°C above pre-industrial levels and related global greenhouse gas emission pathways” (Hulme, 2016, p. 222). The original MoU of U2C was revised in 2021 to align it with the 1.5 degrees Celsius target of the Paris Agreement.

Alongside comprehensive mitigation action, U2C members also actively collaborate on adaptation and resilience measures to address the impacts of climate change. According to the foundational MoU, U2C parties commit to collaboration and coordination efforts designed to advance their respective interim targets for GHG emissions reductions, ensuring these remain consistent with their overarching 2050 goals and broader climate action strategies. Collaboration takes place through multiple structured venues, including the annual U2C General Assembly, which serves as the primary governance forum, the annual sessions of the COPs, and various other significant international climate events and summits.
The collaborative framework encompasses several key operational areas. The parties actively share and promote effective financing mechanisms and innovative funding approaches to support climate action implementation. They also facilitate comprehensive technology sharing and knowledge transfer initiatives. Members work together to build institutional capacity for both climate action and technology adaptation through systematic technology transfer programs and the exchange of technical expertise and best practices. Additionally, they engage constructively in specialized programs and projects developed by other member parties and/or coordinated by The Climate Group as the secretariat organization.
Furthermore, to ensure continued effectiveness, the parties have agreed to conduct comprehensive reviews of the ongoing relevance and functionality of the MoU every five years, strategically aligning this review cycle with the Paris Agreement’s established five-year cycle of increasingly ambitious climate action and enhanced commitments to reducing GHG emissions.
Conceptual and Research Framework
Our analytical framework draws on the seminal work of Liefferink and Wurzel (2017), particularly their nuanced conceptualization of “leadership” and “followership” dynamics in climate governance (see Chap. 2 for details). Liefferink and Wurzel’s framework distinguishes between different types of actors based on their temporal entry into climate initiatives and their subsequent behavior patterns. Climate leaders are characterized not merely by early adoption of climate policies, but by their willingness to undertake ambitious climate action that exceeds minimum requirements and serves as a model for others. These actors typically demonstrate higher levels of commitment in their climate strategies. Conversely, followers enter governance arrangements after initial frameworks have been established, often adopting more cautious approaches that align with proven models rather than pioneering new pathways.
This leadership-followership dynamic becomes particularly relevant in the context of subnational climate governance, where regional and local authorities operate within complex multilevel systems that include national governments, international organizations, and transnational networks. U2C represents an instructive case study for examining these dynamics, as it emerged from subnational initiative rather than top-down national or international mandate, creating distinct opportunities for genuine leadership expression at the subnational level.
Building on this foundation, Chap. 2 argues that U2C’s founding members demonstrate higher and more sustained levels of climate policy effort than entities that joined later. We interpret higher climate policy effort as indicating climate leadership, while lower policy effort suggests climate followership.
Assessing subnational climate policy effort presents several methodological challenges that our research framework addresses. First, climate policy effort is context-dependent, varying according to jurisdictional capacities, economic structures, political systems, and baseline conditions. A jurisdiction with abundant renewable energy resources may demonstrate leadership through rapid clean energy deployment, while another with limited natural advantages might show leadership through innovative policy design or ambitious targets despite challenging circumstances.
To address these differences systematically, we conduct detailed comparative analysis between U2C founding members, early joiners, and subsequent joiners, with particular attention to subnational entities from the same national contexts. This approach allows us to control for nationallevel variables such as the policy competences granted to subnational governments, federal climate policy frameworks, economic conditions, and public attitudes toward climate action.
Furthermore, our analysis focuses on quantifiable indicators of climate leadership, including policies, policy instruments, and GHG emissions reduction targets (Schaub et al., 2022; Steinebach et al., 2024). Additionally, our analysis considers the temporal dimension of climate action, examining whether founding members maintain their leadership positions or whether subsequent joiners eventually converge toward similar levels of ambition.
Second, the temporal dimension of climate policy effort presents challenges in attribution and assessment. Climate policies often have long implementation timelines and may not show immediate results in terms of emissions reductions or other quantitative outcomes (Boasson et al., 2025). The research framework therefore examines both short-term policy outputs and longer-term commitments in the form of GHG emissions reduction targets.
Third, the multilevel nature of climate governance means that subnational climate action occurs within complex institutional environments involving multiple levels of government and diverse stakeholder groups. The framework accounts for these interactions while focusing specifically on the role of subnational governments in policymaking within these broader governance arrangements.
Organization of the Book
This book progresses logically from theoretical foundations through detailed empirical case studies to synthesized findings and concluding remarks. Chapter 2 presents the framework that serves as the theoretical backbone guiding all subsequent empirical analysis throughout the book. The book’s empirical core consists of five detailed case study chapters that systematically compare climate policy effort among founding members, early joiners, and later joiners (within specific national contexts).
Chapter 3 provides the most extensive analysis of the entire book, examining the United States, where 4 founding states—California, Oregon, Vermont, and Washington—are systematically compared with 13 states that joined the U2C in later periods. This chapter leverages the rich US context, which hosts the largest absolute number of U2C members, to provide the most comprehensive empirical insights available.
Chapter 4, the Canadian analysis, systematically compares founding members British Columbia and Ontario with later joiners Québec and the Northwest Territories. The German case is studied in Chap. 5 and contrasts Baden-Württemberg’s distinctive pioneering role as a co-founding jurisdiction with the climate policy effort of seven states that subsequently joined the Coalition. Chapter 6 evaluates the performance of Catalonia, the Spanish U2C founding member, in comparison to the early joiners— the Basque Country and the Foral Community of Navarre—and the later joiners, including Andalusia, the Community of Madrid, and Galicia. Finally, Chap. 7 compares Wales’ climate policy effort with that of Scotland, an early joiner, as well as analyzes the climate policy effort of later joiners Northern Ireland and the Isle of Man.
Chapter 8 synthesizes the findings through systematic cross-case analysis and comparative evaluation, while Chap. 9 concludes by situating our empirical findings within the broader existing climate governance literature and carefully outlining the most promising research directions for future scholarship focused on subnational climate leadership and transnational climate initiatives.
Contributions to the Literature
The first contribution this study makes to the existing academic literature is its systematic demonstration of how climate policy effort and leadership dynamics have developed and evolved over time within the U2C
framework. We examine how climate leadership manifests itself concretely in terms of the specific policies adopted, the diverse policy instruments employed, and the level of ambition of the GHG emissions reduction targets set by the members. Our analysis provides insights into how U2C founding members, early joiners, and later joiners exercise different forms of climate leadership and—with less theoretical emphasis—followership, revealing distinct patterns of engagement and commitment levels across temporal membership categories.
The second contribution lies in our provision of both a research framework and empirical insights that are genuinely comparative across two analytic dimensions. First, our study offers a systematic comparison of founding members, early joiners, and later joiners across five countries. This careful case selection deliberately incorporates variation within these countries—examining different subnational entities within the same national context—as well as meaningful variation across these nations and even between continents, since our research scope encompasses U2C members distributed across both Europe and North America.
The constitutional distribution of climate policy competence varies significantly across these five countries. Germany’s concurrent legislation principle creates a constrained environment where states must navigate narrow windows for policy action (Eckersley et al., 2023). The United States presents the opposite extreme, with its highly decentralized federal structure granting states broad policy powers (Mildenberger, 2021). Spain’s quasi-federal system illustrates the tensions inherent in unclear constitutional boundaries, and like Germany, it is affected by European Union (EU) policies. In Canada, substantial jurisdictional overlaps between national and provincial governments create both opportunities and obstacles (Henstra, 2017). The UK’s constitutional asymmetry creates distinct challenges and opportunities across its constituent nations (Royles & McEwen, 2015).
Along similar lines, our analysis over extended time periods provides empirical evidence on the temporal dimension of climate policy effort and leadership. We assess how robust these leadership patterns remain when confronted with significant changes in the higher echelons of political systems, including shifts in national governments, policy priorities, and other economic, political, and social developments, including socio-political backlash to climate action (Patterson, 2023).
Our third distinctive contribution to the scholarly literature is that we offer a replicable methodological template for expanding this research approach to examine climate action by U2C parties beyond the European and North American contexts. We identify ideal candidates for extending this comparative research framework, highlighting Brazil and Mexico as priority countries since they host three additional founding members of U2C: the Mexican states of Baja California and Jalisco, and the Brazilian state of Acre. These jurisdictions represent potentially insightful cases for understanding how subnational climate leadership emerges in different political, economic, and institutional contexts within Latin America and how leadership shapes climate policy effort.
While this research maintains a deliberately well-defined empirical focus that enables depth of analysis, we acknowledge that there are numerous important aspects of climate leadership by subnational entities and the broader institutional functioning of U2C which we cannot comprehensively cover within the scope of this study. These limitations include detailed analysis of implementation mechanisms, extensive examination of policy outcomes, and comprehensive assessment of the effectiveness of U2C governance structures.
Despite our necessarily focused analytic approach, we remain confident that our findings will significantly reduce existing gaps in the scholarly understanding of subnational climate governance dynamics and provide valuable insights for both academic researchers and policy practitioners working in this rapidly evolving field. By bridging theory and practice in this way, this study contributes to the broader effort to understand how multilevel climate governance can be strengthened and sustained over time.
References
Allison, J. E., Press, D., Horowitz, C., Millard-Ball, A., & Pincetl, S. (2016). Chapter 7. Paths to carbon neutrality: Lessons from California. Collabra, 2(1), 1–15.
Bäckstrand, K., Kuyper, J. W., Linnér, B.-O., & Lövbrand, E. (2017). Non-state actors in global climate governance: From Copenhagen to Paris and beyond. Environmental Politics, 26(4), 561–579. https://doi.org/10.1080/0964401 6.2017.1327485
Boasson, E.L., Peters, G.P., & Tosun, J. (2025). Policy-driven acceleration of climate action. PLOS Climate, 4(5), 1–12. https://doi.org/10.1371/journal. pclm.0000626
Christoff, P., & Eckersley, R. (2021). Convergent evolution: Framework climate legislation in Australia. Climate Policy, 21(9), 1190–1204. https://doi.org/1 0.1080/14693062.2021.1979927
Climate Focus (2013). Acre, Brazil: Subnational Leader in REDD+. Climate Focus: Amsterdam.
Cullenward, D. (2017). California’s foreign climate policy. Global Summitry, 3(1), 1–26. https://doi.org/10.1093/global/gux007
Dimitrov, R. S. (2010). Inside Copenhagen: The state of climate governance. Global Environmental Politics, 10(2), 18–24. https://doi.org/10.1162/ glep.2010.10.2.18
Dubash, N. K. (2021). Varieties of climate governance: the emergence and functioning of climate institutions. Environmental Politics, 30(sup1), 1–25. https:// doi.org/10.1080/09644016.2021.1979775
Eckersley, P., Flynn, A., Lakoma, K., & Ferry, L. (2023). Public procurement as a policy tool: the territorial dimension. Regional Studies, 57(10), 2087–2101.
Francesco, F. D., Leopold, L., & Tosun, J. (2020). Distinguishing policy surveillance from policy tracking: Transnational municipal networks in climate and energy governance. Journal of Environmental Policy & Planning, 22(6), 857–869. https://doi.org/10.1080/1523908X.2020.1785280
Galarraga, I., Murieta, E. S. D., & França, J. (2017). Climate policy at the subnational level. In A. Averchenkova, S. Fankhauser, & M. Nachmany (Eds.), Trends in climate change legislation. Edward Elgar Publishing. https://doi. org/10.4337/9781786435781.00018
García-Jiménez, C. I., & Vargas-Rodriguez, Y. L. (2021). Passive government, organized crime, and massive deforestation: The case of western Mexico. Conservation Science and Practice,	3(12),	e562. https://doi. org/10.1111/csp2.562
Gueiros, C., Jodoin, S., & McDermott, C. L. (2023). Jurisdictional approaches to reducing emissions from deforestation and forest degradation in Brazil: Why do states adopt jurisdictional policies? Land Use Policy, 127, 106582. https:// doi.org/10.1016/j.landusepol.2023.106582
Happaerts, S., Van Den Brande, K., & Bruyninckx, H. (2010). Governance for sustainable development at the inter-subnational level: The case of the Network of Regional Governments for Sustainable Development (nrg4SD). Regional & Federal Studies,	20(1),	127–149.	https://doi. org/10.1080/13597560903187362
Heikkinen, M., Ylä-Anttila, T., & Juhola, S. (2019). Incremental, reformistic or transformational: What kind of change do C40 cities advocate to deal with climate change? Journal of Environmental Policy & Planning, 21(1), 90–103. https://doi.org/10.1080/1523908X.2018.1473151
Henry, L. A., & Sundstrom, L. M. (2007). Russia and the Kyoto Protocol: Seeking an alignment of interests and image. Global Environmental Politics, 7(4), 47–69. https://doi.org/10.1162/glep.2007.7.4.47
Henstra, D. (2017). Climate adaptation in Canada: Governing a complex policy regime. Review of Policy Research, 34(3), 378–399. https://doi.org/10.1111/ ropr.12236
Hermansen, E. A. T., Boasson, E. L., & Peters, G. P. (2023). Climate action postParis: How can the IPCC stay relevant? Npj Climate Action, 2(1), 30. https:// doi.org/10.1038/s44168- 023- 00058- 1
Houle, D., Lachapelle, E., & Purdon, M. (2015). Comparative politics of sub- federal cap-and-trade: Implementing the Western Climate Initiative. Global Environmental Politics,	15(3),	49–73.	https://doi.org/10.1162/ GLEP_a_00311
Hulme, M. (2016). 1.5 C and climate research after the Paris Agreement. Nature Climate Change, 6(3), 222-224.
Jacob, K., & Kannen, H. (2015). Integrated strategies for climate policy integration and coherence: The case of Germany (pp. 1–25). Forschungszentrum für Umweltpolitik. Freie Universität Berlin. ISSN 1612-3026.
Jin, Y. (2025). Subnational science and technology diplomacy: Navigating geopolitical challenges through the lens of California-China climate cooperation. Journal of International Economy and Global Governance, 2(2), 38–64.
Jordan, A., & Huitema, D. (2014). Innovations in climate policy: The politics of invention, diffusion, and evaluation. Environmental Politics, 23(5), 715–734. https://doi.org/10.1080/09644016.2014.923614
Jordan, A., Huitema, D., van Asselt, H., & Forster, J. (2018). Governing climate change: Polycentricity in action? Cambridge University Press.
Jordan, A. J., Huitema, D., Hildén, M., van Asselt, H., Rayner, T. J., Schoenefeld, J. J., Tosun, J., Forster, J., & Boasson, E. L. (2015). Emergence of polycentric climate governance and its future prospects. Nature Climate Change, 5(11), 977–982. https://doi.org/10.1038/nclimate2725
Keohane, R. O., & Victor, D. G. (2011). The regime complex for climate change. Perspectives on Politics,	9(1),	7–23.	https://doi.org/10.1017/ S1537592710004068
Kona, A., Monforti-Ferrario, F., Bertoldi, P., Baldi, M. G., Kakoulaki, G., Vetters, N., Thiel, C., Melica, G., Lo Vullo, E., Sgobbi, A., Ahlgren, C., & Posnic, B. (2021). Global Covenant of Mayors, a dataset of greenhouse gas emissions for 6200 cities in Europe and the Southern Mediterranean countries. Earth System Science Data, 13(7), 3551–3564. https://doi.org/10.5194/ essd- 13- 3551- 2021
Kuyper, J. W., Linnér, B., & Schroeder, H. (2018). Non-state actors in hybrid global climate governance: Justice, legitimacy, and effectiveness in a post-Paris era. WIREs Climate Change, 9(1), e497. https://doi.org/10.1002/wcc.497
Liefferink, D., & Wurzel, R. K. W. (2017). Environmental leaders and pioneers: Agents of change? Journal of European Public Policy, 24(7), 951–968. https:// doi.org/10.1080/13501763.2016.1161657
Mildenberger, M. (2021). The development of climate institutions in the United States. Environmental Politics, 30(sup1), 71–92. https://doi.org/10.108 0/09644016.2021.1947445
Milani, C.R.S., Pinto, J.B., & Facini, A.V. (2025). Climate obstruction in Brazil under the Bolsonaro administration: building empirical and conceptual blocks. Climate and Development, early view, 1-14. 10.1080/17565529.2025.2551952
Ostrom, E. (2010). Beyond markets and states: Polycentric governance of complex economic systems. American Economic Review, 100(3), 641–672. https:// doi.org/10.1257/aer.100.3.641
Ostrom, E. (2011). Background on the institutional analysis and development framework. Policy Studies Journal,	39(1), Article 1. https://doi. org/10.1111/j.1541- 0072.2010.00394.x
Ostrom, V., Tiebout, C. M., & Warren, R. (1961). The organization of government in metropolitan areas: A theoretical inquiry. American Political Science Review, 55(4), 831–842. https://doi.org/10.2307/1952530
Patterson, J.J. (2023). Backlash to Climate Policy. Global Environmental Politics, 23(1), 68–90. 10.1162/glep_a_00684
Royles, E., & McEwen, N. (2015). Empowered for action? Capacities and constraints in sub-state government climate action in Scotland and Wales. Environmental Politics, 24(6),	1034–1054. https://doi.org/10.108 0/09644016.2015.1053726
Schaub, S., Tosun, J., Jordan, A., & Enguer, J. (2022). Climate policy ambition: exploring a policy density perspective. Politics and Governance, 10(3), 226–238. https://doi.org/10.17645/pag.v10i3.5347
Steinebach, Y., Hinterleitner, M., Knill, C., & Fernández-i-Marín, X. (2024). A review of national climate policies via existing databases. npj Climate Action, 3(1), 1–9. https://doi.org/10.1038/s44168-024-00160-y
Thielges, S. (2019). U.S. and German energy policy at a crossroads? The transatlantic partners and the future of energy cooperation. https://americangerman.institute/ publication/u- s- and- german- energy- policy- at- a- crossroads- the- transatlanticpartners- and- the- future- of- energy- cooperation/
Tobin, P., Huitema, D., & Kellner, E. (2024). The empirical realities of polycentric climate governance: Introduction to the special issue. Global Environmental Politics, 24(3), 1–23. https://doi.org/10.1162/glep_a_00758
Unger, C., & Thielges, S. (2021). Preparing the playing field: Climate club governance of the G20, Climate and Clean Air Coalition, and Under2 Coalition. Climatic Change, 167(3–4), 41. https://doi.org/10.1007/ s10584- 021- 03189- 8 Yan, J. (2021). The impact of climate policy on fossil fuel consumption: Evidence from the Regional Greenhouse Gas Initiative (RGGI). Energy Economics, 100, 105333. https://doi.org/10.1016/j.eneco.2021.105333
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CHAPTER 2	
Conceptual Framework
Abstract This chapter develops a conceptual framework for analyzing climate leadership among subnational governments in the Under2 Coalition. Drawing on multilevel governance theory, particularly Type II governance structures, the analysis positions subnational actors as autonomous entities operating within polycentric networks rather than hierarchical systems. The framework adopts Liefferink and Wurzel’s typology of climate leadership—cognitive, entrepreneurial, structural, and exemplary—while acknowledging empirical challenges in distinguishing between types. Central to the framework is reputation theory, which explains differential climate policy effort based on membership timing. Two core propositions guide the empirical analysis: first, founding members demonstrate higher climate policy effort than early and later joiners due to stronger reputational incentives; second, founding members exhibit greater policy durability over time through reputational lock-in effects that increase the costs of policy retreat. The chapter alludes to the importance of both strengthening factors (crisis events, technological developments, electoral dynamics) and weakening factors (economic pressures, political transitions) that shape climate leadership trajectories across temporal and political contexts.
Keywords Climate leadership • Multilevel governance • Policy durability • Reputation theory • Subnational governments

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© The Author(s) 2026
J. Tosun et al., Subnational Climate Leadership Dynamics Among Under2 Coalition Members, Palgrave Studies in Sub-National Governance, https://doi.org/10.1007/978-3-032-12610-8_2
While international climate negotiations, most notably the annual COPs, often dominate headlines, research has compellingly demonstrated that cities, regions, and other subnational actors are emerging as important players in global climate governance (Bäckstrand et al., 2017; Bulkeley et al., 2012; Hsu et al., 2019). Therefore, understanding how and why subnational governments engage in climate action has become a growing concern for both scholars and practitioners.
Our analysis builds on the well-established assumption, informed by extensive research, that subnational governments are not merely implementing policies decided elsewhere; rather, they are actively shaping climate policy through networks, initiatives, and innovative approaches that transcend traditional governmental boundaries (Busch et al., 2018; Hsu et al., 2019; Irepoglu Carreras, 2019; Tosun, Saad, et al., 2023). Furthermore, in multilevel polities, subnational governments benefit from having some degree of competence to adopt and implement their own climate policies. This is especially true in federal systems, where shared policy competences between central and decentralized levels can enable subnational governments to exceed the climate policy effort of the national government (Boyd and Olive 2021), and therefore to practice climate leadership.
This chapter positions our research within the broader conceptual landscape of climate governance and climate leadership to illuminate the drivers and dynamics of subnational climate action. Our analysis focuses on subnational governments’ decisions to join the U2C and their subsequent climate policy effort as U2C members. By examining these processes, we seek to understand not only what motivates subnational governments to engage in transnational climate initiatives but also how their participation translates into sustained climate action.
To achieve this, we draw conceptually from two interconnected bodies of literature. First, we engage with the multilevel governance (MLG) literature, particularly the foundational work of Hooghe and Marks (2001), which provides essential analytical tools for understanding the complex institutional settings within which subnational governments operate. MLG theory helps us navigate the intricate web of relationships between local, regional, national, and international/supranational levels of governance that characterize contemporary climate action.
Following our exploration of MLG, we turn to the expanding literature on climate leadership, which contributes to our analysis in two significant ways. First, this literature offers a nuanced conceptualization of leadership that recognizes multiple types and forms—moving beyond narrow understandings that might overlook important manifestations of leadership. Second, we seek to contribute to the climate leadership literature by developing theoretical propositions about the conditions under which leadership is most likely to emerge and flourish among subnational governments that are U2C parties.
The remainder of this chapter follows this analytic structure, engaging systematically with both literatures before formulating specific propositions that will guide the empirical analysis in this book. The concluding section synthesizes these insights into a coherent conceptual framework.
Multilevel Climate Governance
There exist different definitions of climate action and analytical perspectives for studying how climate action emerges. For the purpose of this book, our definition of climate action corresponds to decisions taken by subnational governments to reduce GHG emissions, thus encompassing different types of subnational climate policies (see, e.g., Almeida et al., 2024; Tosun, 2022). The question of how climate action occurs can be studied from two primary perspectives: politics or governance.
The politics perspective focuses on governmental actors such as members of parliament, government officials, and public administrators. This approach examines the climate policy preferences of these actors, their strategies for ensuring policy adoption, and how institutional and contextual factors shape the design of the climate policies eventually adopted (Jordan et al., 2022; Moore et al., 2024; Sullivan-Thomsett et al., 2024; Willis, 2020). The governance perspective differs fundamentally from the politics perspective in that it explicitly acknowledges that decision making and policy implementation involve both governmental and nongovernmental actors (Bäckstrand et al., 2017; Bulkeley et al., 2012; Irepoglu, 2019; Jordan et al., 2018).
At first glance, our research might appear misaligned with the governance perspective since we focus primarily on governmental actors. However, this assessment would fail to account for important theoretical developments within governance scholarship. The governance concept has undergone numerous refinements, among which the concept of MLG, as developed by Hooghe and Marks (2001), stands as particularly influential. According to these authors, MLG captures the idea that multiple levels of authority—supranational, national, regional, and local—interact with each other in complex ways. More fundamentally, the core insight of MLG is that decision-making authority is dispersed across multiple territorial levels and involves various governmental and non-governmental actors operating within interconnected networks.
From this MLG perspective, our focus on subnational rather than national governments clearly qualifies our research for the application of the MLG framework. Subnational governments operate within the multilevel system on which MLG focuses, navigating relationships not only with higher levels of government but also with peer jurisdictions, international networks, and various non-state actors. This positioning makes the MLG perspective particularly apt for understanding how subnational climate action unfolds within broader governance arrangements.
Hooghe and Marks (2001) distinguish between two distinct types of MLG that reflect fundamentally different organizational logics. Type I MLG echoes federalist thought, conceiving the dispersion of authority as occurring within a limited number of non-overlapping jurisdictional boundaries at distinct territorial levels. Decision-making powers are dispersed across these general-purpose jurisdictions within a relatively stable hierarchical structure characterized by clear lines of accountability and nested relationships between levels.
Type II MLG provides a markedly different vision of governance, in which jurisdictions are characterized by overlapping boundaries and flexible arrangements that adapt to changing governance demands. Rather than being organized territorially, these jurisdictions are functionally differentiated. Multiple jurisdictions formed across various levels and entities interact, collaborate, and perform distinct functions within a more fluid governance system. As acknowledged, for instance, by Di Gregorio et al. (2019), Wurzel et al. (2019), and Heinen et al. (2022), this conception of MLG resonates strongly with the concept of polycentric governance developed by Vincent Ostrom et al. (1961) and further elaborated by Elinor Ostrom (2010), which emphasizes the relative independence of constituent units to establish their own norms and rules within their specific domains (see also Jordan et al., 2015, 2018).
The analytical implications of these two types are significant for understanding subnational climate governance. When adopting a Type I MLG perspective, the hierarchical relationship between national and subnational governments features prominently (Bakvis & Brown, 2010; Biedenkopf, 2017), with emphasis on how authority flows between clearly defined territorial levels. Conversely, when following the Type II perspective, the analytical focus shifts to individual jurisdictions and their multifaceted relationships—not only with national governments but also, and perhaps more importantly, with peer jurisdictions across similar and different governance levels. These interactions can take various forms, ranging from cooperative and collaborative to competitive or even conflictive (Heinen et al., 2022).
Our analytical approach aligns with Type II MLG even though we focus on subnational entities that are territorially defined. The justification for this approach lies in our primary interest in the climate action subnational governments take based on their own assessment of climate urgency and through collaboration with other subnational entities, whether located within the same country or across national boundaries. In other words, we presume that subnational governments who join U2C are willing to take climate action that not only complements the efforts of national governments but also moves significantly beyond what is required or expected at the national level.
This approach reflects the Type II MLG logic in several key ways. First, these subnational actors operate with some level of autonomy in defining their climate priorities and enacting appropriate policies in response to the demands of the national government. Second, their engagement in transnational networks like U2C demonstrates the kind of flexible collaboration that characterizes Type II governance arrangements. Third, their climate actions often transcend the hierarchical expectations of traditional intergovernmental relations, instead reflecting horizontal relationships and peer-to-peer learning that cut across territorial boundaries.
Leadership in Climate Governance
One of the key topics in international politics has been determining which governments act as leaders and which follow them (Underdal, 1998). Liefferink and Wurzel (2017) have adapted the concept of leadership to the realm of international climate politics and climate governance. Before we engage with the different types of leadership, it is important to justify that leadership is indeed the most appropriate concept for this research as there exist alternative concepts for establishing which actors demonstrate greater climate policy effort.
The most important alternative concept is that of the pioneer, on which Liefferink and Wurzel (2017) also elaborate. According to the authors, “pioneers carry out activities which, depending on the subsequent circumstances and events ‘in the field’, may or may not help others to follow” (Liefferink & Wurzel, 2017, p. 953). Thus, pioneers mainly focus on internal action without explicitly seeking to attract followers, though they may unintentionally set examples for others. “A leader, on the other hand, has the explicit aim of leading others, and, if necessary, to push others into a follower position. Therefore, leaders usually attract followers, or at least aim to do so” (Liefferink & Wurzel, 2017, p. 953). According to Torney (2019), followers adopt climate change policies, ideas, institutions, approaches, or techniques after observing their adoption by leaders or pioneers. Like the previously discussed concepts, followership represents intentional action.
Which of these two concepts—leadership or pioneer—is more accurate for our analysis? As is customary in research, at some point we must make assumptions about the actors we study, since without such assumptions it would be difficult to develop a compelling conceptual framework. It follows that both our theoretical argument and empirical insights must be evaluated against the backdrop of these foundational assumptions. Therefore, it is crucial to make these assumptions explicit and provide adequate justification for them.
Our central assumption regarding the subnational governments participating in U2C is that they aim to act as leaders rather than pioneers. This assumption is primarily informed by the self-description of U2C and its member governments. The U2C members commit themselves to “acting as climate leaders” (Under2 Coalition, 2024, p. 2). This leadership orientation implies a deliberate strategy to shape the behavior of others, distinguishing these actors from pioneers, who may advance ambitious policies without necessarily seeking to influence followers. By adopting this assumption, we can better analyze how these subnational governments position themselves within broader climate governance networks.
Building on this, we assume that they have both high internal and external ambitions for climate leadership. The external dimension is twofold: first, it refers to acting as leaders within U2C itself, thereby stimulating the overall level of ambition within the coalition. Second, given that U2C is composed of subnational governments, this external dimension also refers to influencing other subnational governments within the countries where the members are based and which are not U2C members.
Within the concept of leadership, actors seeking to be leaders are expected to adopt certain strategies for inducing others to follow them. Liefferink and Wurzel (2017) identify four types of climate leadership. The first is cognitive leadership, which relies on the power of ideas, knowledge, and expertise. This leadership type involves promoting ideas that shape subsequent action by other actors. Tobin et al. (2023, p. 189) argue that the EU’s adoption of the European Green Deal can be regarded as an example of cognitive leadership by the United States. US politicians such as Alexandria Ocasio-Cortez established the idea of an ambitious and comprehensive green growth agenda, which the EU picked up and established its own version of.
Second, entrepreneurial leadership involves diplomatic and bargaining skills, encompassing the ability to draw attention to issues, propose innovative solutions, and broker compromises. This type of leadership has been frequently discussed in the literature in relation to the EU’s aspirational role in international climate politics (Tobin et al., 2023). While the application of this leadership concept appears most intuitive in the international domain, entrepreneurial leadership can, in principle, also be observed at the subnational level.
Third, structural leadership relates primarily to military and economic power, though in climate governance, economic dimensions are most relevant. This includes market power for businesses, consumption power for consumers, and systemic relevance based on an actor’s contribution to climate problems. For example, large GHG emitters may have significant “issue-specific” structural power in international negotiations, derived from their centrality to climate mitigation efforts (Tobin et al., 2023). At the subnational level, economically affluent entities may have greater structural power since producers of goods might be inclined to design their products according to the preferences and standards of these wealthy markets.
Finally, exemplary leadership consists of providing good examples for other actors, either intentionally or unintentionally. Subnational governments can serve as “living laboratories” that demonstrate the feasibility and effectiveness of climate policies. When a subnational government successfully implements innovative climate measures, other subnational actors can observe these examples and adapt similar approaches suitable to their own contexts.
Leadership over Time
As with any policy decision taken by a government—at any level of the political system—leadership is a deliberate choice, and choices are the outcomes of decision-making processes. Several factors affect the process and outcomes of decision making, most of which are dynamic in nature. Consequently, climate leadership must also be regarded as a phenomenon that is inherently dynamic, subject to both strengthening and weakening forces that shape how governments prioritize and address climate change across different temporal and political contexts.
Strengthening Effects
Crisis events often serve as powerful catalysts for enhanced climate governance. Natural disasters, extreme weather events, or environmental catastrophes can create critical windows of opportunity where public demand for action intensifies and the political costs of inaction become starkly apparent. The 2003 European heatwave, for instance, significantly elevated climate concerns across the continent and resulted in most European cities adopting comprehensive prevention and warning plans for extreme temperatures (García-Herrera et al., 2010). These crisis-driven policy responses demonstrate how acute environmental or climate-related events can rapidly transform political priorities and create momentum for sustained climate action.
Technological developments can substantially reinforce leadership by making climate solutions more economically attractive and politically feasible. As renewable energy costs plummeted dramatically over the past decade (Abbott et al., 2023), governments found it increasingly easier to champion clean energy transitions that simultaneously addressed climate goals and enhanced economic competitiveness. This technological shift has fundamentally altered the political calculus surrounding climate policy, transforming what was once seen as an economic burden into a potential source of competitive advantage. Consequently, this technological evolution might have significantly strengthened leadership in climate governance by aligning environmental objectives with economic interests.
Electoral cycles and changing public opinion represent another strengthening mechanism with multifaceted implications. Younger generations tend to demonstrate higher levels of climate concern (Parth et al., 2020), and as their political influence grows through increased voter participation, politicians increasingly view climate action as electorally advantageous rather than politically risky. In particular, the rise of influential social movements, such as Fridays for Future, has induced German politicians to adopt a more pronounced pro-climate stance, illustrating how grassroots mobilization can directly influence policy positions (Tosun & Debus, 2025).
Related to this demographic shift, increasing electoral support for green and ecological parties can fundamentally alter climate leadership dynamics through two distinct pathways. First, green parties can directly join governing coalitions, thereby strengthening climate leadership through direct participation in policy-making processes and cabinet positions. Second, an increasing vote share for green parties can exert significant competitive pressure on other political parties, compelling them to adopt more proclimate positions and engage in strengthened climate leadership as a strategic response to shifting electoral preferences.
Weakening Effects
The same or similar factors can result in a weakening of climate leadership. Among these factors are economic pressures, which frequently undermine climate governance. During recessions or periods of high energy costs, governments may prioritize short-term economic relief over long-term climate investments, viewing environmental policies as luxury expenditures that can be deferred during times of fiscal constraint. As Liefferink and Wurzel (2017) argue, the 2008 financial crisis led several countries to delay or scale back environmental regulations as they focused on economic recovery, demonstrating how economic crises can rapidly shift policy priorities away from climate action (see also Burns & Tobin, 2020).
Political transitions can equally alter climate leadership trajectories in dramatic ways. Changes in governing parties, especially those with fundamentally different ideological orientations toward government intervention and climate policy, can result in significant policy reversals and institutional dismantling. Leadership changes may result in the instatement of officials who view climate action as economically burdensome, scientifically questionable, or ideologically objectionable. A particularly illustrative case is provided by the recent oscillations in US climate policy across presidential administrations (Smith, 2024; Tosun, Heinz-Fischer, & Luo, 2023).
Furthermore, effective climate governance requires sustained attention across multiple policy domains over extended timeframes. As initial enthusiasm wanes and implementation challenges emerge, political leaders may prioritize more immediate, tangible issues that offer clearer political rewards, as already predicted by Downs (1972).
Interaction Between Factors
These factors often interact cyclically. Strong leadership phases may generate backlash that empowers opposition forces (Patterson et al., 2025), while periods of weak leadership can create conditions for renewed mobilization. Understanding these dynamics suggests that sustainable climate governance requires building institutional resilience that can weather political transitions while maintaining long-term policy continuity across changing political landscapes. Furthermore, different institutional architectures shape climate policy development of which the constitutionally defined distribution of policy competencies is the most fundamental one.
Propositions
This section integrates the individual elements of the preceding conceptual discussion to establish a coherent conceptual framework for understanding climate leadership dynamics and to formulate specific propositions that will guide the subsequent empirical analysis.
Our analytic foundation rests on the premise that subnational governments participating in U2C operate within multilevel governance systems that structure their climate policy choices. They adopt climate policies not merely as isolated responses to U2C commitments, but as strategic decisions that reflect their policy preferences, institutional capacity, and their aspirations to influence climate governance at multiple scales (Irepoglu, 2019). In doing so, they deliberately seek to exercise leadership directed toward other subnational entities within their domestic contexts as well as toward the broader U2C network.
Drawing on Liefferink and Wurzel’s (2017) typology, we distinguish four analytically distinct yet often overlapping forms of leadership: cognitive leadership (shaping ideas and problem definitions), entrepreneurial leadership (brokering new solutions and coalitions), structural leadership (leveraging institutional position and resources), and exemplary leadership (demonstrating best practices through action).
While our empirical analysis engages with these different leadership types and identifies them wherever the empirical evidence permits, we acknowledge the inherent methodological challenge of distinguishing between them definitively. Such differentiation would require comprehensive knowledge of the underlying motivations and strategic calculations of subnational governments—data that is rarely accessible or reliably documented. Our analytic approach therefore focuses on observable policy actions while recognizing that these actions represent attempts to exercise one or more forms of leadership, even when the precise type or combination remains ambiguous. We equally recognize that in the case of some subnational governments, policy action can also be the outcome of a deliberate choice to follow leaders, which can be motivated by the wish to remain followers or eventually become leaders themselves.
The central variation we seek to explain concerns both the type of climate action U2C members take and the temporal sustainability of their policy effort. To theorize this variation, we draw on reputation theory, a well-established framework in International Relations scholarship that posits reputation as a valuable strategic asset (Pfeiffer et al., 2012). For governmental actors, cultivating and maintaining a positive reputation— whether for reliability, innovation, or environmental stewardship—can yield tangible benefits including enhanced access to international funding, stronger partnership opportunities, and increased influence in policy networks. Conversely, a damaged reputation can result in diplomatic isolation, reduced credibility, and diminished capacity to achieve policy objectives.
We presume that joining U2C but demonstrating no or low climate policy effort could damage a subnational government’s reputation, while high policy effort could strengthen it. Nonetheless, we contend that while reputation considerations matter for all U2C members, their impact varies systematically according to the timing and circumstances of membership. We therefore distinguish analytically between founding members (those instrumental in establishing U2C), early joiners (those who joined shortly after its inception), and later joiners (those who joined after the coalition had become established).
Our theoretical framework generates the following proposition: Founding members face the strongest reputational incentives and therefore demonstrate the highest levels of sustained climate policy effort. Having invested their credibility in launching the organization, they bear primary responsibility for its success and face the greatest reputational costs from organizational failure or their own policy backsliding. Early adopters also confront significant reputational pressures, as their visible, early commitment signals strong climate policy credentials, but these pressures are somewhat attenuated compared to founders since they bear less direct responsibility for organizational outcomes. Later entrants, while still subject to reputation effects through their voluntary association with the coalition’s goals, face comparatively lower stakes since they joined an already-established network and therefore experience less pressure for exceptional performance. They could also see more benefit in being followers than leaders (Proposition 1).
Our second proposition builds on the membership characteristics framework while incorporating the crucial temporal dynamics of both climate policy effort and reputation formation. The relationship between reputation and sustained policy commitment represents a well-established research domain in International Relations, with scholars examining whether positive or negative reputational consequences exert stronger behavioral constraints on state actors and how reputational capital accumulates and depreciates over time (e.g., Baser, 2024).
Extending our earlier analysis, we argue that founding members face not only the strongest initial incentives for ambitious climate action but also the most compelling pressures to sustain and potentially enhance their commitments over time. This dynamic stems from reputational lock-in effects—the phenomenon whereby early, visible commitments to policy leadership create escalating expectations that make policy retreat increasingly costly (Panke, 2015). For founding members, any perceived weakening of climate ambition would signal fundamental inconsistency between their stated values and actual behavior, potentially undermining their credibility across multiple policy domains and damaging their capacity to exercise future leadership.
This theoretical insight connects directly to the growing literature on climate policy durability, which seeks to understand the mechanisms that enable climate policies to survive political transitions, economic pressures, and shifting public priorities (Jordan & Moore, 2020). Our contribution to this debate is to highlight how reputational costs can serve as an endogenous stabilizing mechanism, particularly for actors who have made highly visible commitments to leadership. Founding members of organizations face what economists would recognize as a “sunk cost” problem in reverse: having invested heavily in building reputational capital around environmental leadership, they have strong incentives to protect this investment through continued policy effort.
The reputational stakes create an asymmetric incentive structure where the costs of policy retreat significantly exceed the benefits of maintaining the status quo. This asymmetry should be most pronounced for founding members, who face the highest reputational exposure, followed by early joiners, who benefit from association with organizational success but bear somewhat lower responsibility for its continuation. Later entrants, while still subject to reputational consequences for dramatic policy reversals, face comparatively lower stakes since their environmental credentials are less tightly bound to the organization’s trajectory. Consequently, they could be inclined to lower climate ambition in response to changes in economic, political, and social conditions (Proposition 2).
Conclusion
This chapter has established a conceptual framework for understanding subnational climate policy effort and leadership within multilevel governance systems. Drawing on characterization of Type II multilevel governance systems, we position subnational governments as autonomous actors operating within polycentric networks.
Our framework adopts Liefferink and Wurzel’s (2017) typology of climate leadership—cognitive, entrepreneurial, structural, and exemplary— while acknowledging the practical challenges of distinguishing between these forms empirically. Central to our framework is the application of reputation theory to explain variation in climate policy effort among U2C members. We argue that reputation considerations create differential incentives based on membership timing, with founding members facing the strongest pressures for sustained climate action due to reputational lock-in effects. This dynamic generates two key propositions: first, that founding members demonstrate higher levels of climate policy effort than early and later joiners; and second, that founding members exhibit greater policy durability over time due to escalating reputational costs of retreat.
References
Abbott, B. W., Abrahamian, C., Newbold, N., Smith, P., Merritt, M., Sayedi, S. S., Bekker, J., Greenhalgh, M., Gilbert, S., King, M., Lopez, G., Zimmermann, N., & Breyer, C. (2023). Accelerating the renewable energy revolution to get back to the Holocene. Earth’s Future, 11(9), e2023EF003639. https://doi. org/10.1029/2023EF003639
Almeida, P., González Márquez, L. R., & Fonsah, E. (2024). The forms of climate action. Sociology Compass, 18(2), e13177. https://doi.org/10.1111/ soc4.13177
Bäckstrand, K., Kuyper, J. W., Linnér, B.-O., & Lövbrand, E. (2017). Non-state actors in global climate governance: From Copenhagen to Paris and beyond. Environmental Politics, 26(4), 561–579.
Bakvis, H., & Brown, D. (2010). Policy coordination in federal systems: Comparing intergovernmental processes and outcomes in Canada and the United States. Publius: The Journal of Federalism, 40(3), 484–507. https:// doi.org/10.1093/publius/pjq011
Baser, E. T. (2024). Reputations and change in international relations. International Studies Quarterly, 68(3), sqae097. https://doi.org/10.1093/ isq/sqae097
Biedenkopf, K. (2017). Gubernatorial entrepreneurship and United States federal- state interaction: The case of subnational regional greenhouse gas emissions trading. Environment and Planning C: Politics and Spaces, 35(8), 1378–1400. https://doi.org/10.1177/2399654417719286
Boyd, B., & Olive, A. (Eds.). (2021). Provincial policy laboratories: Policy diffusion and transfer in Canada’s Federal System. University of Toronto Press.
Bulkeley, H., Andonova, L., Bäckstrand, K., Betsill, M., Compagnon, D., Duffy, R., Kolk, A., Hoffmann, M., Levy, D., Newell, P., Milledge, T., Paterson, M., Pattberg, P., & VanDeveer, S. (2012). Governing climate change transnation- ally: Assessing the evidence from a database of sixty initiatives. Environment and Planning. C, Government & Policy, 30(4), 591–612. https://doi. org/10.1068/c11126
Burns, C., & Tobin, P. (2020). Crisis, climate change and comitology: Policy dismantling via the backdoor? JCMS: Journal of Common Market Studies, 58(3), 527–544. https://doi.org/10.1111/jcms.12996
Busch, H., Bendlin, L., & Fenton, P. (2018). Shaping local response – The influence of transnational municipal climate networks on urban climate governance. Urban Climate, 24, 221–230. https://doi.org/10.1016/j.uclim.2018.03.004
Di Gregorio, M., Fatorelli, L., Paavola, J., Locatelli, B., Pramova, E., Nurrochmat, D. R., May, P. H., Brockhaus, M., Sari, I. M., & Kusumadewi, S. D. (2019). Multi-level governance and power in climate change policy networks. Global Environmental Change,	54,	64–77.	https://doi.org/10.1016/j. gloenvcha.2018.10.003
Downs, A. (1972). Up and down with ecology—The issue-attention cycle. The Public Interest, 28(1), 38–50.
García-Herrera, R., Díaz, J., Trigo, R. M., Luterbacher, J., & Fischer, E. M. (2010). A review of the european summer heat wave of 2003. Critical Reviews in Environmental Science and Technology, 40(4), 267–306. https://doi. org/10.1080/10643380802238137
Heinen, D., Arlati, A., & Knieling, J. (2022). Five dimensions of climate governance: A framework for empirical research based on polycentric and multi-level governance perspectives. Environmental Policy and Governance, 32(1), 56–68. https://doi.org/10.1002/eet.1963
Hooghe, L., & Marks, G. (2001). Multi-level governance and European integration. Rowman & Littlefield Publishers.
Hsu, A., Höhne, N., Kuramochi, T., Roelfsema, M., Weinfurter, A., Xie, Y., Lütkehermöller, K., Chan, S., Corfee-Morlot, J., Drost, P., Faria, P., Gardiner, A., Gordon, D. J., Hale, T., Hultman, N. E., Moorhead, J., Reuvers, S., Setzer, J., Singh, N., Weber, C., & Widerberg, O. (2019). A research roadmap for quantifying non-state and subnational climate mitigation action. Nature Climate Change, 9(1), 11–17. https://doi.org/10.1038/s41558- 018- 0338- z
Irepoglu Carreras, Y. (2019). Problem‐Solving Across Literatures: Comparative Federalism and Multi‐Level Governance in Climate Change Action. European Policy Analysis, 5(1),	117-134.	10.1002/epa2.2019.5.issue-1 10.1002/epa2.1066
Jordan, A., Huitema, D., van Asselt, H., & Forster, J. (2018). Governing climate change: Polycentricity in action? Cambridge University Press.
Jordan, A., Lorenzoni, I., Tosun, J., i Saus, J. E., Geese, L., Kenny, J., Saad, E. L., Moore, B., & Schaub, S. G. (2022). The political challenges of deep decarbonisation: Towards a more integrated agenda. Climate Action, 1(1), 6. https:// doi.org/10.1007/s44168- 022- 00004- 7
Jordan, A., & Moore, B. (2020). Durable by design? Policy feedback in a changing climate. https://doi.org/10.1017/9781108779869
Jordan, A., Huitema, D., Hildén, M., van Asselt, H., Rayner, T. J., Schoenefeld, J. J., Tosun, J., Forster, J., & Boasson, E. L. (2015). Emergence of polycentric climate governance and its future prospects. Nature Climate Change, 5(11), 977–982. https://doi.org/10.1038/nclimate2725
Liefferink, D., & Wurzel, R. K. W. (2017). Environmental leaders and pioneers: Agents of change? Journal of European Public Policy, 24(7), 951–968. https:// doi.org/10.1080/13501763.2016.1161657
Moore, B., Geese, L., Kenny, J., Dudley, H., Jordan, A., Prados Pascual, A., Lorenzoni, I., Schaub, S., Enguer, J., & Tosun, J. (2024). Politicians and climate change: A systematic review of the literature. WIREs. Climate Change, 15(6), e908. https://doi.org/10.1002/wcc.908
Ostrom, E. (2010). Polycentric systems for coping with collective action and global environmental change. Global Environmental Change, 20(4), 550–557. https://doi.org/10.1016/j.gloenvcha.2010.07.004
Ostrom, V., Tiebout, C. M., & Warren, R. (1961). The organization of government in metropolitan areas: A theoretical inquiry. American Political Science Review, 55(4), 831–842. https://doi.org/10.2307/1952530
Panke, D. (2015). Lock-in strategies in international negotiations: The deconstruction of bargaining power. Millennium: Journal of International Studies, 43(2), 375–391. https://doi.org/10.1177/0305829814550504
Parth, A.-M., Weiss, J., Firat, R., & Eberhardt, M. (2020). “How dare you!”— The influence of Fridays for future on the political attitudes of young adults. Frontiers in Political Science, 2, 611139. https://doi.org/10.3389/ fpos.2020.611139
Pfeiffer, T., Tran, L., Krumme, C., & Rand, D. G. (2012). The value of reputation. Journal of the Royal Society Interface, 9(76), 2791–2797. https://doi. org/10.1098/rsif.2012.0332
Patterson, J., Anisimova, K., Logg-Scarvell, J., & Kaiser, C. (2025). Reactions to policy action: socio-political conditions of backlash to climate change policy. Policy Sciences, 58	(2),	287–320.	https://doi.org/10.1007/ s11077-025-09578-5
Smith, D. C. (2024). ‘The’ key 2024 election involving climate change and the energy transition: Biden vs Trump 2.0 and the matter of global trust in the US. Journal of Energy & Natural Resources Law, 42(2), 131–136. https://doi. org/10.1080/02646811.2024.2341542
Sullivan-Thomsett, C., Jordan, A., Lorenzoni, I., & Geese, L. (2024). How not to transform: Learning from the backlash against low-carbon heating in Germany. In CAST Briefing 28.
Tobin, P., Torney, D., & Biedenkopf, K. (2023). EU climate leadership: Domestic and global dimensions. In T. Rayner, K. Szulecki, A. J. Jordan, & S. Oberthür (Eds.), Handbook on European Union climate change policy and politics (pp. 187–200). Edward Elgar Publishing. https://doi. org/10.4337/9781789906981.00025
Torney, D. (2019). Follow the leader? Conceptualising the relationship between leaders and followers in polycentric climate governance. Environmental Politics, 28(1), 167–186. https://doi.org/10.1080/09644016.2019.1522029
Tosun, J. (2022). Addressing climate change through climate action. Climate Action, 1(1), 1. https://doi.org/10.1007/s44168- 022- 00003- 8
Tosun, J., & Debus, M. (2025). The Fridays for future movement and the repoliticization of climate change policy in Germany. In P. Tobin, M. Paterson, & S. D. VanDeveer (Eds.), Stability and politicization in climate governance (1st ed., pp. 19–34). Cambridge University Press. https://doi. org/10.1017/9781009352444.003
Tosun, J., Heinz-Fischer, C., & Luo, R. (2023). Who takes the lead? A disaggregate analysis of the EU’s engagement in the Clean Energy Ministerial and Mission Innovation. Journal of Cleaner Production, 382, 135240. https://doi. org/10.1016/j.jclepro.2022.135240
Tosun, J., Saad, E. L., Glückler, J., Irigoyen Rios, A., & Lehmann, R. (2023). Country-specific participation patterns in transnational governance initiatives on sustainability: Preliminary insights and research agenda. Global Challenges, 7(8), 2300012. https://doi.org/10.1002/gch2.202300012
Under2 Coalition. (2024). Global climate leadership: Memorandum of understanding. Under2 Coalition.
Underdal, A. (1998). Leadership in international environmental negotiations: Designing feasible solutions. In A. Underdal (Ed.), The politics of international environmental management (Vol. 4, pp. 101–127). Springer Netherlands. https://doi.org/10.1007/978- 94- 011- 4946- 4_6
Willis, R. (2020). Too hot to handle? The democratic challenge of climate change. Bristol University Press.
Wurzel, R. K. W., Liefferink, D., & Torney, D. (2019). Pioneers, leaders and followers in multilevel and polycentric climate governance. Environmental Politics, 28(1), 1–21. https://doi.org/10.1080/09644016.2019.1522033
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CHAPTER 3	
nited States
Abstract This chapter examines climate policy efforts across 17 US states that joined the Under2 Coalition at different timepoints, analyzing founding members (California, Oregon, Vermont, and Washington), early joiners (Connecticut, Massachusetts, Minnesota, New Hampshire, New York, and Rhode Island), and late joiners (Colorado, Hawaii, Maine, Maryland, Nevada, New Jersey, and Virginia). The analysis systematically compares climate policy adoption, policy instrument diversification, and greenhouse gas emissions reduction targets across these membership categories. California emerges as the dominant climate leader, leveraging its unique Clean Air Act waiver and market power to demonstrate cognitive, structural, entrepreneurial, and exemplary leadership. Other founding members show more variable patterns, with partisan politics creating significant constraints. Early joiners like Massachusetts and New York amplified existing frameworks through the Under2 Coalition membership, while states like New Hampshire represent followership despite early participation. Late joiners generally maintain lower policy effort levels, though some developed ambitious frameworks prior to coalition entry. The findings provide mixed support for the propositions regarding founding member leadership and policy durability.
Keywords Climate policy instruments • Greenhouse gas reduction targets • Partisan polarization subnational climate governance • United States
© The Author(s) 2026	37
J. Tosun et al., Subnational Climate Leadership Dynamics Among Under2 Coalition Members, Palgrave Studies in Sub-National Governance, https://doi.org/10.1007/978-3-032-12610-8_3
Introduction
Climate governance in the United States has followed an inconsistent path at the federal level, largely shaped by partisan divisions. The Democratic Party has generally promoted climate action, while the Republican Party has been less ambitious and even dismantled existing climate frameworks (Jotzo et al., 2018; Masur, 2022; Rabe, 2010; Tosun et al., 2023). However, the multileveled nature of US governance arrangements—span- ning federal, state, and local levels—has created alternative pathways for policy-based climate action. Despite partisan divides that extend to subnational levels, state governments have emerged as important actors in climate action (Mildenberger, 2021; Trachtman, 2019). This has produced a decentralized approach to climate governance rather than a traditional top-down model, exemplifying what scholars such as Jordan et al. (2018), Jordan and Huitema (2014), Jordan et al. (2015), and Tobin et al. (2024) have identified as a broader shift toward polycentric climate governance (see Chap. 2).
State-level climate initiatives emerged in the early 2000s, with California, Oregon, and Washington launching the West Coast Governors Global Warming Initiative in 2003 to reduce GHG emissions (duVair et al., 2007). This was followed in 2005 by a coalition of northeastern states that signed the RGGI, which became operational in 2009 as the first mandatory carbon cap-and-trade program in the United States. These pioneering efforts introduced renewable energy mandates, economy-wide emissions targets, and market-based carbon pricing mechanisms during a period of federal inaction on climate policy (Karapin, 2018).
State momentum continued building through the 2010s as international climate negotiations progressed. In May 2015, California partnered with the German state of Baden-Württemberg to convene subnational leaders for the signing of the U2C MoU, strengthening subnational support in the run-up to the Paris Climate Conference.
Even though the Trump administration (2017–2021 and 2025- present) withdrew from the Paris Agreement, the number of U2C members expanded in the United States (see also Chap. 1). This participation makes the United States a laboratory for examining subnational climate governance dynamics. This chapter leverages this rich empirical context.
Founding Members
California
California’s climate leadership story began decades before the inception of U2C and has its roots in an environmental legacy stretching back to the 1960s that would prove instrumental in shaping twenty-first-century climate policy (Allison et al., 2016; Leffel, 2018; Mazmanian & Jurewitz, 2020). This foundation enabled California to pioneer subnational climate action in the 2000s, beginning with groundbreaking vehicle emission standards in 2002 (Meckling & Nahm, 2018) and culminating in the landmark Global Warming Solutions Act (GWSA) in 2006, better known as AB 32, one of the world’s first comprehensive climate framework laws (Bedsworth & Hanak, 2013; Meckling & Nahm, 2022; Sperling & Eggert, 2014).
What transformed California from a regional leader into a global climate innovator was a unique combination of legal authority and market power. Unlike any other state, California holds an exclusive federal waiver under the Clean Air Act (CAA) that allows it to set stricter vehicle emission standards, while other states can only choose between federal standards or California’s more stringent requirements. This legal advantage, combined with California’s massive automotive market, creates what scholars term a “super-regulator” effect—the state’s innovations ripple outward to shape both subnational and national policy (Carlson, 2008). The sheer size of California’s car market often compels manufacturers to meet the state’s standards nationwide rather than maintain separate production lines, generating what political economists call the “California effect” (Perkins & Neumayer, 2012; Vogel, 1995).

The GWSA is a collective term for laws in various US states that aim to reduce GHG emissions. To distinguish California’s act from those subsequently adopted by other US states, we use the term “AB32” for California’s version.

However, California’s true genius lies not just in leveraging its unique automotive advantage, but in creating a replicable governance architecture through AB32. The framework established clear GHG emissions targets while delegating implementation authority to the capable Air Resources Board, which designs and continuously updates programs through successive scoping plans. This approach evolved from sector- specific regulations into a comprehensive, economy-wide system featuring cap-and-trade mechanisms layered onto detailed standards spanning transportation, electricity, buildings, land-use, and beyond—all anchored by long-term carbon neutrality targets.
When California co-founded U2C in 2015, it did not represent a policy shift but rather an amplification of existing momentum. The initiative provided California with an international platform to accelerate policy diffusion (Boyd, 2019), positioning the state as a powerful engine for spreading climate innovation globally.
Oregon
Oregon combines the traits of a leader and a follower, having developed a climate governance that is innovative yet fragmented because its progress has often been hindered by internal political divisions. This tension has defined Oregon’s climate journey from its early recognition of the challenge to its ongoing struggle to translate vision into comprehensive action.
The state’s climate awareness emerged remarkably early, establishing a global warming taskforce in 1988—nearly two decades before most jurisdictions began climate planning (Graves et al., 2020). Yet it took until 2007 for this early recognition to crystallize into legislation, when House Bill 3543 finally established GHG reduction goals and created the Oregon Global Warming Commission to provide strategic guidance and monitor progress (Graves et al., 2020). The Commission has since functioned as Oregon’s climate conscience, serving as an agenda-setter that develops roadmaps and recommendations to drive sectoral action.
Oregon’s followership is evident in its adoption of California’s proven approaches, including the Low-Emissions Vehicle (LEV) standards and ambitious targets for 100% Zero-Emissions Vehicle (ZEV) sales by 2035. However, the state’s leadership ambitions have repeatedly collided with political reality. Oregon failed to meet its 2020 benchmark of reducing emissions 10% below 1990 levels and has been unable to enact the economy- wide cap-and-trade program that would anchor its climate strategy.
The most dramatic illustration of this political dysfunction came during legislative attempts in 2019 and 2020, when ambitious climate bills collapsed amid unprecedented partisan warfare. Despite Democratic majorities in both chambers, Republicans wielded Oregon’s two-thirds quorum requirement as a weapon, repeatedly walking out to deny quorum and effectively paralyzing the legislative process. Democrats lacked the supermajority needed to override these tactics, creating a governance crisis that highlighted the fragility of climate action in polarized political environments (VanderHart, 2025).
Faced with legislative deadlock, Governor Kate Brown demonstrated adaptive governance by pivoting to executive action, directing state agencies to pursue science-based GHG emissions reductions through regulatory channels (Executive Order No. 20-04) (Lorenzen, 2020). The Department of Environmental Quality responded by establishing declining emission caps for fossil fuel suppliers—a workaround that achieved some policy goals despite the absence of comprehensive legislation.
U2C membership offers Oregon external legitimacy and international visibility that helps it sustain climate ambition when internal political divisions threaten to derail progress. When Oregon does lead effectively, it exemplifies cognitive leadership—contributing knowledge, analysis, and innovative thinking that advances the broader climate agenda, even when its own implementation capacity remains constrained by political realities.
Vermont
Despite being a small state with limited market influence, Vermont positioned itself as an early climate innovator, consistently punching above its weight in clean energy and environmental policy. The state’s leadership trajectory began with followership in 1996 when it adopted California’s LEV standards. This early commitment to stringent environmental standards continued in 2001 when Vermont co-signed a regional climate action plan with New England Governors and Eastern Canadian Premiers (NEG-ECP), demonstrating its willingness to engage in cross-border climate cooperation (see Chap. 4). Vermont maintained this momentum by establishing statutory GHG emissions targets in 2006 and by becoming the first state to ban hydraulic fracturing in 2012—a bold move that signaled its commitment to transitioning away from fossil fuels (Scarcioffolo et al., 2021).
By the mid-2010s, Vermont’s clean energy progress was quantifiably impressive, boasting the nation’s least fossil fuel-intensive electricity sector (Sovacool et al., 2014). This achievement provided a strong foundation when Vermont joined U2C, viewing membership as diplomatic positioning within a global network of subnational climate ambition. The U2C platform amplified Vermont’s leadership profile, giving the state an international stage to showcase its achievements and influence broader climate discourse.
However, Vermont’s most significant climate policy evolution came after joining U2C. The 2020 GWSA marked a turning point by establishing legally binding climate obligations and creating a Climate Council responsible for designing consecutive action plans. This comprehensive framework consolidated Vermont’s position as an exemplary leader—a state that demonstrates how ambitious climate action can be achieved regardless of size or market power, inspiring other small jurisdictions to pursue similarly bold approaches.
Washington
Washington began its climate efforts later than other U2C founding members, but it ultimately built one of the United States’ most comprehensive regulatory frameworks through a combination of executive persistence and strategic legislative timing. Washington’s initial climate foray came through the Energy Independence Act in 2006, which required major utilities to source 15% of their electricity from renewables by 2020. The state government quickly expanded its ambition, establishing a GHG emissions reduction framework with reporting requirements and GHG emissions targets by 2008, followed by Executive Order 09-05 in 2009, which directed state agencies to implement cross-sectoral climate strategies. By the time Washington co-founded U2C in 2015, this solid foundation was already in place, positioning the state for the acceleration that would follow.
The post-2015 period revealed both Washington’s climate ambitions and its political constraints. Progress accelerated significantly but relied heavily on executive action, as a Republican-controlled Senate consistently blocked legislative efforts to strengthen GHG emissions targets. The Clean Air Rule in 2016 introduced a cap-and-reduce system for large emitters, demonstrating the administration’s determination to advance climate policy despite legislative gridlock. This executive-driven approach continued with landmark legislation in 2019: the Clean Energy Transformation Act, mandating 100% clean electricity by 2045, and the Clean Buildings Act, establishing performance standards for large commercial buildings.
The political breakthrough came in 2021 when shifting partisan control finally enabled comprehensive legislative action. The legislature enacted the Climate Commitment Act—a sophisticated cap-and-invest program modeled on California’s pioneering one—alongside the Clean Fuel Standard, which mandates a 20% reduction in the carbon intensity of transportation fuel by 2035 (Roy Chowdhury et al., 2025). These measures transformed Washington’s regulatory architecture, extending state authority across economic sectors while creating market-based instruments to achieve GHG emissions targets.
Washington’s approach exemplifies cognitive leadership in climate governance. Rather than pioneering entirely new approaches, the state systematically studied and adapted proven models from other jurisdictions—particularly California’s cap-and-trade system—while developing innovative solutions tailored to its specific economic and political context.
Early Joiners
Connecticut
Connecticut’s foundational climate policy emerged in 2007 with Public Act 07-242 (an act concerning electricity and energy efficiency), which integrated energy efficiency requirements into state planning and established a renewable portfolio standard. This was quickly followed by the GWSA in 2008, which set GHG emissions limits and created a reporting framework. Then, in 2009, Connecticut became a founding member of the RGGI, positioning it early in this pioneering multi-state cap-and- trade system.
Where Connecticut truly distinguished itself was in pioneering climate finance mechanisms. The creation of the Clean Energy Finance and Investment Authority in 2011 through Public Act No. 11-80 marked a watershed moment, as this institution later evolved into theUnited States' first state green bank. This institutional innovation has since been replicated across multiple US states, representing Connecticut’s most significant contribution to climate policy diffusion across the United States (Nix et al., 2025). The state reinforced its regional approach in 2013 by signing the Multi-State ZEV MoU, a particularly strategic move given that transportation had become Connecticut’s largest GHG emitting sector.
However, Connecticut’s climate trajectory reveals inconsistent commitment. When the state joined U2C in 2015, it aligned with Governor Dan Malloy’s broader diplomatic approach and provided some international visibility, but the core priorities remained RGGI participation and advancing climate finance rather than achieving a comprehensive transformation toward sustained climate action. This uneven commitment has become more apparent in recent years, with Connecticut’s withdrawal from the Transportation & Climate Initiative Program in late 2021 and the decision of its legislative committee in 2023 to stall a proposal to adopt California’s Advanced Clean Cars II standards.
Despite these setbacks, Connecticut can be attributed some degree of climate leadership. The state demonstrated exemplary leadership by creating replicable models—particularly the green bank concept—that other jurisdictions could adopt. Simultaneously, Connecticut showed entrepreneurial leadership by innovating financial mechanisms that addressed market failures in clean energy investment, proving that climate leadership can emerge through institutional creativity rather than just regulatory ambition.
Massachusetts
Massachusetts established its climate policy foundation in 2008 with two landmark pieces of legislation that would define its long-term approach. The GWSA set legally binding targets, including an 80% GHG emissions reduction below 1990 levels by 2050, while empowering the Executive Office of Energy and Environmental Affairs to establish interim GHG emissions reduction targets and enforcement mechanisms. Simultaneously, the Green Communities Act provided the planning frameworks and investment tools needed to support local-level policy implementation. The state reinforced this regulatory foundation by participating in the launch of RGGI that same year, adding market-based carbon pricing to its emerging climate policy portfolio.
What distinguishes Massachusetts is its approach to climate policy development—systematically building on existing foundations rather than pursuing dramatic policy shifts. The Clean Energy and Climate Plans of 2010 and 2015 provided regular progress assessments toward 2020 goals, while the state’s decision to join U2C in 2015 reflected both its commitment to maintaining ambition and its strategic interest in learning from peer jurisdictions (Union of Concerned Scientists, 2016).
The next phase of Massachusetts’ climate policy evolution was characterized by consolidation rather than dramatic expansion. The 2050 Decarbonization Roadmap (2020) provided detailed sectoral pathways, while An Act Creating a Next-Generation Roadmap for Climate Policy (2021) updated the state’s target to net-zero GHG emissions by 2050. Rather than introducing entirely new policy instruments, this period emphasized expanding and reinforcing existing approaches. The Climate Leader Communities initiative, launched in 2025, exemplifies this strategy by broadening municipal engagement through an enhanced version of the earlier Green Communities framework.
This systematic layering approach reflects Massachusetts’ distinctive form of cognitive leadership in climate governance. The state excels at synthesizing research, analyzing climate policy performance, and adapting successful models from other jurisdictions while maintaining long-term strategic coherence. Combined with exemplary leadership—particularly its role in demonstrating how sustained institutional commitment can generate comprehensive climate frameworks—Massachusetts offers a compelling model for states seeking to build durable, evidence-based climate governance systems.
Minnesota
While Minnesota’s climate governance journey illustrates how early momentum can stall in the absence of sustained political commitment, it also demonstrates how renewed leadership can revitalize ambitious climate action.
Minnesota began as an early climate pioneer, launching its Climate Change Action Plan in 2003 to integrate climate concerns into energy and environmental policy frameworks. This early foundation was strengthened by the Next Generation Energy Act in 2007, which established GHG emissions reduction goals, and the comprehensive Climate Change Advisory Group report in 2008, which provided detailed sectoral strategies for legislative action. These initiatives created what appeared to be a solid institutional foundation for sustained climate progress.
However, promise did not translate into performance. Minnesota missed its 2015 GHG emissions reduction target, and the 2016 Climate Solutions report delivered a sobering assessment: the state was not on track to meet its future climate goals. This implementation gap revealed the difference between setting ambitious targets and creating the political and institutional capacity necessary to achieve them.
Minnesota’s decision to sign the U2C MoU in October 2015 reflected this limited ambition, treating the international initiative primarily as an external benchmark rather than as a catalyst for enhanced action (Minnesota Pollution Control Agency, 2017). During this period, Minnesota’s role was fundamentally that of a follower—maintaining basic commitments while other states advanced more aggressive policies.
The turning point came in 2019, when Governor Tim Walz issued an executive order (19-37) establishing a Climate Subcabinet to coordinate climate action across state agencies. This institutional innovation signaled a shift toward more systematic climate governance. Progress accelerated in 2021 with the Energy Conservation and Optimization Act, which expanded efficiency mandates, and the adoption of California’s LEV and ZEV standards—Minnesota’s belated embrace of proven climate policy models.
The most significant breakthrough came in 2023 when the legislature enacted an updated Climate Action Framework, committing Minnesota to net-zero GHG emissions by 2050. This commitment finally aligned Minnesota with peer states that had made similar pledges years earlier, marking the state’s transition from climate laggard to renewed participant in ambitious subnational climate action. Minnesota’s recent trajectory suggests that while early leadership advantages can be squandered, they can also be recovered through focused political commitment and institutional reform.
New Hampshire
New Hampshire’s climate governance exemplifies how early institutional development does not guarantee sustained policy ambition. The state established credible climate planning mechanisms but has struggled to translate this groundwork into the comprehensive climate policy frameworks adopted by peer jurisdictions, resulting in a persistent gap between climate recognition and climate action.
New Hampshire’s climate journey began promisingly with the establishment of the Climate Change Policy Task Force in 2007, which produced the state’s first climate action plan in 2009. This foundational document recommended policies across multiple sectors and established GHG emissions reduction targets, though notably these remained nonbinding. The state reinforced its early climate commitment by joining RGGI in 2009, integrating its Clean Power Act into the regional carbon market and demonstrating willingness to participate in innovative multistate climate mechanisms.
However, this initial momentum gave way to an extended plateau characterized by limited policy development. New Hampshire joined U2C in 2015—an early joiner among US states—and approved the Energy Efficiency Resource Standard in 2016, but these remained isolated actions rather than components of an expanding climate policy framework. Even these modest advances faced political volatility, with the efficiency standard being disrupted in 2021 before being restored and updated in early 2022, illustrating the fragility of climate policy in politically competitive environments.
Today, New Hampshire significantly lags behind other U2C members in both the scope and ambition of its climate policies. The state lacks binding GHG emissions reduction targets, has not adopted electric vehicle (EV) mandates, and offers limited incentive programs for clean energy transitions—policy gaps that are particularly striking given its early engagement with climate planning. This performance suggests that New Hampshire’s role within U2C has been more symbolic than substantive, maintaining membership without embracing the policy innovations that characterize more ambitious coalition members.
Despite these shortcomings, New Hampshire has maintained consistency in certain areas, particularly through its continued participation in RGGI and modest progress on climate framework development and sectoral decarbonization efforts. This pattern reveals a state that recognizes climate challenges and maintains basic institutional capacity but lacks the political commitment or advocacy coalition strength necessary to advance comprehensive climate governance. New Hampshire thus represents a cautionary example of how early climate engagement can stagnate without sustained political leadership and lacking capability or willing to innovate new climate policies.
New York
New York’s climate leadership originated during the 1970s energy crisis, when the state pioneered energy efficiency programs that would become foundational to its later climate strategy. This early experience with energy policy provided institutional knowledge that proved crucial as climate concerns emerged. The state formalized its climate ambitions in 2002 with the State Energy Strategy, which introduced New York’s first GHG emissions reduction goals. By 2009, New York had become a founding member of RGGI, and one year later adopted its first comprehensive Climate Action Plan, successfully embedding market-based carbon pricing into its policy framework.
New York’s decision to join U2C in 2015 aligned naturally with its existing climate strategy, though the coalition’s direct influence on the state’s trajectory is difficult to isolate. What is clear is that the period following U2C membership witnessed decisive policy developments that consolidated New York’s position as a national climate leader. The pivotal moment came in 2019 with the passage of the Climate Leadership and Community Protection Act, landmark legislation that mandated a zero- emissions electricity grid by 2040 and created the Climate Action Council to develop detailed implementation pathways through comprehensive scoping plans.
New York’s approach to the most challenging sectors—transportation and buildings—reveals strategic adaptation of proven models rather than policy innovation from scratch. The state adopted California-style vehicle standards, implementing Advanced Clean Trucks regulations in 2021 and Advanced Clean Cars II standards in 2022. For buildings, New York broke new ground by becoming the first state to mandate all-electric systems for new buildings, commencing in 2023 on a phased schedule.
The scale and sophistication of New York’s climate framework reflect multiple dimensions of subnational leadership (Karapin, 2018). The state demonstrates structural leadership through its economic size and influence: as home to the nation’s largest state public power utility, New York’s policy choices ripple throughout energy markets. Cognitive leadership manifests itself in New York’s systematic development of evidence-based climate policies and institutional frameworks that other states can transfer at. Finally, it also exhibits exemplary leadership by proving that large, economically diverse states can accelerate decarbonization while maintaining economic competitiveness, providing a powerful demonstration effect for other major state economies.
Rhode Island
Rhode Island is another small state with strong climate governance. It entered regional alliances early, co-signing the NEG-ECP’s Climate Change Action Plan in 2001 and, a year later, publishing its own Greenhouse Gas Action Plan (2002). Agenda-setting was complemented by the Least-Cost Procurement statute (2006), which required utilities to pursue cost-effective efficiency. Rhode Island signed the RGGI memorandum in 2007, well before its launch, and by 2009, when it entered into force, the state had already positioned itself within the region’s marketbased carbon regime.
In 2014, the Resilient Rhode Island Act set up a cross-sectoral agency and established long-term goals to tackle mitigation, while other states joining U2C supplied external benchmarking. The decisive policy adopted after joining the coalition was the Act on Climate (2021), which made Rhode Island’s climate goals legally binding, including GHG net-zero by 2050 (Kim and Park, 2024). This same act also mandated iterative planning (updates and strategies) while retaining the aspirational nature of previous goals. Rhode Island’s trajectory shows fundamentally cognitive leadership, but there are also instances of exemplary leadership, such as the aforementioned statute for energy efficiency.
Late Joiners
Colorado
Colorado’s state-level climate policy started with renewable energy standards, which evolved into comprehensive legislation. Amendment 37 (2004) required large utilities to source 10% of their electricity from renewables by 2015 and created a renewable energy credit market. Colorado then established GHG emissions inventories and preliminary non-binding GHG emissions targets through executive action (2008). Exemplary leadership emerged in 2014 when Colorado became the first US state to regulate methane leakage from oil and gas operations, later becoming a model for federal policy (Dai et al., 2020).
When the United States retreated from the Paris Agreement in 2017, Colorado responded with an executive order adopting Paris-aligned goals and announcing entry to the US Climate Alliance the same day. In 2019, with legislative support, the state enacted the Climate Action Plan to Reduce Pollution with binding reduction targets. Complementary measures included adopting California’s ZEV standards and the Clean Heat Plan Act (2021), requiring utilities to cut emissions from gas use in buildings. In 2023, the GHG emissions targets were updated to achieve net- zero emissions by 2050 with stronger regulatory authority for implementation through the GHG Reduction Measures bill.
Colorado joined the U2C in 2024, later than most US states and after consolidating its climate framework toward full carbon neutrality. The state was a late joiner that did not rely on the coalition for direction but used it to amplify its international credibility. Given its pioneering methane rules, Colorado’s leadership is mainly exemplary and cognitive.
Hawaii
Hawaii’s legal framework began with the GWSA (2007), which is modeled on California’s AB32 and set one of the nation’s first binding GHG emissions reduction targets, attempting to return to 1990 levels by 2020 (University of Hawaii Economic Research Organization, 2008). The following year, the state pursued clean energy through the Hawaii Clean Energy Initiative (2008), partnering at the federal level with the US Department of Energy to combine achieving GHG emissions reductions with strengthening energy security.
Ambition rose with Act 97 (2015), making Hawaii the first state to set a 100% renewable electricity goal to be achieved by 2045. Act 15 (2018) then established a statewide net-zero GHG emissions target for the same year, to be attained through a GHG Sequestration Task Force charged with aligning land-use, forests, soils, and coasts with mitigation. Hawaii joined U2C in 2018 for an external validation of its policy-based climate action and to align its statutory trajectory with global subnational entities. Nevertheless, the state's climate policy revolves more around local energy challenges and regional cooperation than U2C itself.
Subsequent legislation, including Act 74 (2021) and Act 238 (2022), filled gaps in interim milestones regarding vehicle emissions and GHG emissions reduction targets, respectively. This was reinforced through fostering sectoral transitions, such as by implementing energy efficiency portfolio standards in buildings and participation in the Multi-State ZEV Memorandum of Understanding for medium and heavy-duty vehicles. Overall, the binding GHG emissions reduction targets and the cross- sector framework from Act 238 suggest that Hawaii demonstrates both exemplary and cognitive leadership.
Maine
Maine’s climate policy began with the Climate Action Law (2003), mandating the first GHG emissions reduction targets and action plan (2004) with biennial reporting and sectoral recommendations. In 2005, the state co-founded the RGGI, which was launched in 2009 to embed carbon pricing into electricity generation, and later established the Efficiency Maine Trust (2009) to channel revenues into building efficiency.
Progress stalled under Republican Governor Paul LePage (2011–2018), who opposed climate policy and limited new initiatives (Portland Press Herald, 2018). The only notable measure was a biomass procurement program, criticized as economically rather than environmentally driven (McKibben, 2019). However, the institutional architecture remained intact, and momentum returned with Governor Janet Mills of the Democratic Party. The state joined the US Climate Alliance (2019) and created the Climate Council through Public Law 2019, Chapter 476, institutionalizing multi-sectoral working groups and setting statutory GHG emissions reduction targets of 45% below 1990 levels by 2030 and 80% by 2050. This law also reformed the Renewable Portfolio Standard and thereby established heat pump deployment initiatives to accelerate decarbonization.
The “Maine Won’t Wait” Action Plan (2020) translated targets into concrete measures with deadlines and accountability metrics. Maine joined U2C following this resurgence in climate policy in 2021. The revised MoU of the U2C established a net-zero-by-2050 baseline that Maine and other members have committed to, though this did not alter the state’s trajectory but rather positioned Maine among subnational leaders pursuing more ambitious climate action.
Regarding sectoral policies, Maine joined the Multi-State ZEV MoU (2020) and adopted California’s ZEV Program (2021), committing itself to selling 30% of its new medium- and heavy-duty vehicles as zero emission by 2030. Maine considered adopting California’s Advanced Clean Trucks and Advanced Clean Cars II regulations, but the Board of Environmental Protection voted against it in 2024. Despite this setback, Maine demonstrates cognitive leadership through strategic guidance, as exemplified by the “Maine Won’t Wait” Action Plan.
Maryland
The Healthy Air Act (2006), which served as a springboard for the state’s entry into RGGI by limiting power sector emissions, marks the beginning of state-level climate policy in Maryland (Ruth, 2008). The state government then adopted California’s clean-car program (2007), developed a Climate Action Plan (2008), and established its first GHG emissions targets through the GHG Reductions Act (2009). EmPOWER Maryland (2008) subsequently created a platform for incentivizing energy efficiency through energy conservation measures in low-income households.
A stagnation period followed, without the adoption of dedicated climate policies, until the Clean Energy Jobs Act (2019) expanded offshore wind energy. The main turning point came with the Climate Solutions Now Act (2022), which introduced binding net-zero GHG emissions reduction targets for 2045 and required state agencies to develop statewide plans, as articulated in the 2023 Climate Pollution Reduction Plan. Maryland also adopted California’s Advanced Clean Cars II regulations (2023), mandating 100% ZEV sales by 2035.
Entering U2C in 2023 provided Maryland with credibility for its climate policy approach through joining a subnational platform. Maryland has not been a source of horizontal climate policy diffusion to other states, marking it as a follower rather than a leader. Although EmPOWER Maryland represents an innovative measure, the fact that is was not adopted by the other US states indicates that Maryland lacks cognitive leadership.
Nevada
Nevada started early in developing state-level climate policy with the adoption of the Renewable Portfolio Standard (1997) but stagnated until 2017, when the state government moved rapidly to catch up with the other US states (Selin & Vandeveer, 2021). Nevada first established a Clean Energy Fund, a green bank focused on financing clean growth for underserved communities. However, the inflection point was Senate Bill 254, which set both GHG emissions reduction and net-zero targets. Notably, Nevada’s GHG emissions reduction targets aimed for 45% below 2005 levels by 2030. These targets were complemented by the Climate Strategy (2020), which created a basis for cross-sectoral climate action.
In 2021, Nevada adopted California’s LEV III and ZEV requirements through its Clean Cars Nevada regulations, starting with model year 2025, and joined U2C—mostly for external validation, but also as part of broader efforts to improve climate ambition after years without progress. Subsequently, Nevada developed the Priority Climate Action Plan (2024) to reinforce near-term measures and reach its 2030 goal. The state’s trajectory has been that of a follower due to its stagnation period, but there are signs of emerging cognitive leadership .
New Jersey
New Jersey developed its climate policy through a sequence of laws and regulations, starting with the Global Warming Response Act (2007), which mandated early GHG emissions reduction targets and obliged the Department of Environmental Protection to enable monitoring and reporting systems for emissions. The state later enacted the Offshore Wind Economic Development Act (2010), creating wind renewable energy certificates and authorizing tax incentives for this sector.
Little progress was made besides the Solar Act (2012) while Chris Christie, a Republican governor, was in office (2010–2018), but momentum returned in 2018 when the state re-entered the RGGI and increased renewable energy portfolio and energy efficiency targets through the Clean Energy Act. The EV Act (2020) established EV sales targets and charging infrastructure goals, plus a fund to incentivize EV purchases. These measures were complemented by Executive Order 274 (2021), which filled gaps through an interim goal of 50% emission reductions by 2030.
Despite the stagnation in climate policy developed between 2010 and 2018, New Jersey had developed a robust state-level climate policy by the time it joined U2C (2024), elevating its international profile. Given strategic offshore wind development and multi-sector climate strategies, the state demonstrated cognitive leadership under Democratic governments.
Virginia
Virginia’s early approach to climate policy was limited to non-binding planning documents providing broad guidance, such as the Virginia Energy Plans (2007), but climate action gained momentum after joining U2C in 2017. Despite being a late addition to U2C, Virginia joined early for a southern state.
No immediate action followed its entry into U2C, but in 2020 the state enacted the Virginia Clean Economy Act, establishing binding clean electricity requirements and a Renewable Portfolio Standard. The act mandates retiring carbon-emitting electric generating units by 2045, with earlier deadlines for coal and large oil units (2024), and sets a non-binding goal of net-zero GHG emissions by 2045.
Virginia joined RGGI in 2020—late nationally but as the first southern state to do so, though an attempted withdrawal in 2023 has created legal uncertainty over whether Virginia is still part of the initiative. Momentum for climate policy continued in 2021 with the Commonwealth Clean Energy Policy, extending non-binding net-zero requirements to all major sectors. The transport sector advanced by adopting California’s Advanced Clean Cars I (2021) and Clean Cars II (2022) regulations, requiring 100% ZEV sales by 2035, but in 2024 Governor Glenn Youngkin of the Republicans announced Virginia would stop following Clean Cars II starting in 2025 (Governor of Virginia, 2024). Virginia had also adopted California’s LEV standards (2021), and building codes were updated for better energy efficiency (2023).
Rapid acceleration followed U2C membership, with Virginia beginning to show exemplary and cognitive leadership until 2022. However, under the current Republican governor, Virginia is no longer a leader or follower of leading US states, as the state's climate policy has regressed.
Comparative Analysis
Policies
Figure 3.1 reveals that California began implementing climate policies earlier and accumulated more policies than other founding members. Rather than relying on the U2C framework, the state functioned as its own source of climate policy innovation (Carlson, 2008). Washington entered later with moderate climate policy effort, then accelerated policy development in the late 2010s and early 2020s following the enactment of the Clean Energy Transformation Act (2019) and the establishment of a cap-and-invest program (2021)—changes that occurred once partisan veto points were removed.

Fig. 3.1 Adoption of climate laws, plans, programs, and regulations by founding signatories

Oregon’s policy curve shows a late start with minimal growth until the early 2020s, when the state pivoted toward programs and plans as alternatives for overcoming legislative gridlock. Vermont began policy development earlier than Oregon and Washington, albeit on a smaller scale, before making significant advances in the early 2020s through comprehensive planning initiatives (Sovacool et al., 2014).
While U2C membership corresponds with post-2015 policy adoption across all states, this alignment is less pronounced in California, which had already established its policy leadership before this period.
Figure 3.2 reveals distinct policy development patterns among early joiners. Massachusetts and New York emerge as the most prolific states in climate policy development, both accelerating after 2008/2009—likely driven by RGGI implementation and initial policy frameworks—followed by a second wave from 2019–2023 when Massachusetts enacted several pieces of new legislation.

Fig. 3.2 Adoption of climate laws, plans, programs, and regulations by early-

joining signatories

Connecticut demonstrates a more gradual approach, beginning with laws before progressively adding programs, plans, and regulations that reflect initiatives in green banking and transportation. Minnesota experienced an extended plateau from 2008–2015, after which new climate policies emerged consistently.
New Hampshire presents a contrasting case, with minimal new climate policy expansion resulting in low overall totals by 2024. The state’s climate policy landscape remains dominated by non-legislative measures, reinforcing its follower or laggard status. Rhode Island began meaningful climate policy development in 2014, focusing primarily on plans with some legislation before constructing a comprehensive climate framework.
Examining the post-2015 U2C influence, New Hampshire shows limited policy growth during this period, while other early joiners demonstrate substantial increases in their climate policies following U2C participation.
Figure 3.3 illustrates that late joiners generally maintain a lower overall number of climate policies, though with notable variation in timing and approach. Colorado showed modest progress through the 2000s before laws and regulations gained prominence from 2019 onward. Hawaii experienced early advancement (2007–2009), followed by limited activity in the mid-2010s, then sustained climate policy growth.
Maine maintained steady policy growth until 2018, then increased climate policy development significantly in 2019–2020 before reaching a high plateau. Maryland’s climate policy development occurred in two distinct phases: initial activity from 2007–2012, followed by minimal change until a substantial push in 2022–2024 that aligned with the adoption of net-zero GHG emissions reduction targets and transportation regulations designed to accelerate progress toward decarbonization, as laid out in its 2023 Climate Pollution Reduction Plan.
Nevada presents a unique case, showing no policy activity until 2019, when it experienced rapid growth driven by comprehensive executive measures. New Jersey followed a similar pattern, with early activity from 2007–2012 followed by stagnation until 2018, when regulations increased notably through 2023.
Virginia had minimal climate policy before 2017—primarily plans—but demonstrated strong growth from 2018 to 2024 that included the enactment of legislative measures. However, the state now appears to be experiencing climate policy reversal.

Fig. 3.3 Adoption of climate laws, plans, programs, and regulations by later-
joining signatories

Across all late joiners, the increase in the number of climate policies corresponds with the Paris Agreement timeframe. Regarding U2C influence, Colorado, New Jersey, and Maryland joined too recently to allow us for assessing potential network effects. Maine joined in 2021 but has not adopted new climate policies since. Nevada exhibits increased climate policy activity since its entry into U2C in 2021, while Hawaii (2018) and Virginia (2017) have long enough been members of U2C to suggest climate policy growth following membership.
Policy Instruments
Figure 3.4 reveals that California maintains the earliest, most extensive, and most diversified climate policy instrument portfolio, utilizing all instrument types except voluntary agreements. Notably, subsidies, standards, and certifications were implemented early on, while taxes, cap-and- trade, and public procurement emerged later. Bans, information instruments, and trading mechanisms began in 2015 and continue operating today.

Fig. 3.4 Policy instruments to reduce regional GHG emissions by founding signatories

Vermont also demonstrates early policy instrument diversification, implementing six instrument types before 2015 and adding two thereafter. Significantly, Vermont pioneered carbon cap-and-trade implementation even before RGGI’s launch in 2009.
Among late joiners, Oregon began the development of its climate policy with standards and subsidies before adding bans, public procurement, and taxes after 2015. Washington initially employed standards, information and trading instruments, and taxes, before incorporating cap-and- trade and bans post-2015.
Figure 3.5 demonstrates that standards represent the most prevalent and earliest policy instrument among early joiners, implemented by every state except New Hampshire. Carbon cap-and-trade systems follow as the second-most common policy instrument, primarily driven by RGGI participation. Minnesota presents a notable exception, lacking RGGI membership and utilizing only standards and subsidies.
Public procurement emerged later as a policy tool, appearing in New York, Connecticut, and Massachusetts. Certification and labeling programs were implemented exclusively in New York and Massachusetts from 2009 onward, while bans spread across multiple states—New York, Rhode Island, Massachusetts, and New Hampshire—during the mid- 2010s through early 2020s.
In terms of policy instrument diversification, Massachusetts leads with eight different policy types, followed closely by New York with seven. Minnesota demonstrates the least diversification, employing only two instrument types.
The post-2015 period reveals varying levels of climate policy innovation: New York, Massachusetts, and New Hampshire each added three new instruments and Connecticut incorporated two, while Rhode Island and Minnesota showed no new instrument diversification during this timeframe.
Figure 3.6 reveals that standards typically emerged first among the late joiners, though overall instrument diversification remains more limited compared to earlier joiner groups. Nevada began earliest but subsequently only added subsidies. Information and training instruments appeared early across several states: Colorado (2008), Hawaii (2007), and Maine (2004).
Voluntary agreements show varied adoption patterns, starting in Virginia in 2000, arriving in Hawaii in 2009, and reaching Maine in 2020.

Fig. 3.5 Policy instruments to reduce regional GHG emissions by early-joining signatories

Cap-and-trade systems primarily emerged through RGGI participation, beginning in Maine and Maryland in 2007. New Jersey followed a similar trajectory, initially joining RGGI before pausing after 2011 and rejoining in 2018. Virginia implemented cap-and-trade from 2020–2023, but renewal is uncertain due to the state’s RGGI withdrawal. Hawaii represents a unique case, initiating its own statutory cap-and-trade program in 2014.
Subsidies experienced distinct surges: Maryland, Virginia, and Nevada expanded these instruments around 2010, while Maine and New Jersey saw growth in the 2020s. Public procurement appeared in Maine from 2015–2018 through biomass contracts, with Hawaii and Maryland

Fig. 3.6 Policy instruments to reduce regional GHG emissions by later-joining signatories adopting similar instruments in 2021. Bans emerged more recently, featuring in Maryland since 2017 and Virginia since 2020. Notably, taxes remain absent across all late-joiner US states.
Regarding post-2015 instrument adoption, Hawaii (1), Maine (3), Maryland (2), and New Jersey (3) introduced new climate policy instruments during this period. Following U2C membership, only Hawaii added further instruments, though the timeframe remains limited for assessment. Consequently, most policy instruments predate U2C participation among late joiners.
Targets
Figure 3.7 elucidates that all U2C founding members established longterm GHG emissions reduction goals early, beginning in the mid-2000s. Medium-term goals followed a similar pattern, with Oregon as the notable exception, neglecting these until 2020. Short-term goals show more variation: only California implemented early short-term targets, while Vermont added these in 2020.
California has progressed beyond its initial benchmarks and currently maintains a 40% GHG emissions reduction goal by 2030 and carbon neutrality by 2045, both stemming from its foundational AB32 framework. Oregon’s medium-term goal adoption in 2020 followed its failed 2019

Fig. 3.7 Greenhouse gas emissions reduction targets by founding signatories
cap-and-trade legislative attempt, emerging as part of subsequent executive action.
The timing of goal-setting appears unrelated to U2C membership or the post-2015 period. However, the original U2C MoU proposed ambitious 80–95% GHG emissions reduction targets based on climate science. The 2021 MoU revision established the collective goal of achievingnet- zero GHG emissions by 2050. These changes demanded target strengthening by members who had not previously aligned with these standards.
Washington exemplifies this alignment process, with the Department of Ecology updating targets in 2020 while pursuing carbon neutrality ahead of the U2C revision, bringing the state into compliance with Paris Agreement commitments (Shields, 2023).
Figure 3.8 shows that the early joiners’ medium- and long-term GHG emissions reduction targets align perfectly, originating from identical policies. Connecticut, Massachusetts, and Minnesota established these targets around 2010, while New York implemented them in the early 2000s. Rhode Island delayed adoption until 2021, and New Hampshire remains without any targets. Among early joiners, Massachusetts alone has adopted short-term targets, doing so in 2021.
A notable target-setting wave occurred around RGGI’s launch, with subsequent updates across all participating states except New Hampshire and Rhode Island. While not visible in Fig. 3.8, these updates occurred

between 2019 and 2023, establishing net-zero commitments by 2050 or similarly ambitious targets.
This timing corresponds with both the Paris Agreement framework and the period following the states’ entry into U2C, suggesting alignment between state-level goal-setting and broader international and coalition commitments.
Figure 3.9 shows that late joiners have not yet established short-term targets. Target adoption patterns vary significantly across states and timeframes. Virginia uniquely focused on long-term targets, implementing these in 2020 through the Clean Economy Act.
For medium-term targets, Colorado, Hawaii, Maryland, and New Jersey adopted these around 2010—a full decade before Virginia’s targetsetting began. Maine and Nevada followed later, establishing mediumterm goals in 2019.
Long-term target adoption shows two distinct waves: Colorado (nonbinding), Maine, and New Jersey implemented long-term targets before 2010, while the remaining states adopted these during the post-2015 period. Regarding U2C influence, only Virginia and Hawaii established long-term targets after joining the coalition. Hawaii’s targets emerged through Act 15 (2018), passed by the state legislature.

Leadership
Our analysis shows a varied pattern of leadership roles by the US states that joined U2C. California has been cast as a super regulator and diplomatic entrepreneur using its unique economic weight and CAA waiver to innovate climate policies that have diffused across the US states and beyond (Boyd, 2017; Leffel, 2018; Mazmanian & Jurewitz, 2020). The state also shared its regulatory templates and long-term targets, exemplifying all four leadership types outlined by Wurzel et al. (2019): cognitive (agenda-setting), structural (legal leverage and market power), entrepreneurial (coalition-building), and exemplary (policy innovation).
Other founding members, like Oregon and Washington, oscillated between leadership and followership as internal partisan veto points limited structural leadership and forced those states to rely on executive action and U2C membership to reinforce the legitimacy of climate action (Meckling & Trachtman, 2024).
Early joiners, like Massachusetts and New York, show how U2C can amplify existing climate policy trajectories. Both states already had climate targets in place when joining U2C through RGGI and state policies, but U2C membership provided a platform to show cognitive and exemplary leadership with measures such as the Community Protection Act (2019) adopted by the government of New York. On the other hand, Minnesota and New Hampshire represent cases of followership, adopting fewer and less ambitious climate policy instruments before and after joining U2C, which for them was more of an external benchmark than a driver of policy innovation (Busby & Urpelainen, 2020). The differences suggest that besides U2C membership, leadership hinges on several factors such as pre-existing state capacity, political will, and regional collaborations. Even international agreements such as the 2015 Paris Agreement form part of the conditions faciliating climate leadership.
Late joiners, such as Colorado, Hawaii, and Maine, already had domestic climate policies in place and, in this case, U2C seems to have been strategically useful for increasing the visibility of their state-level climate action among other US states. Hawaii pioneered a renewable electricity target (2015) and Colorado was the first to implement methane leakage regulations (2014); although both measures predated membership, they became better known through U2C affiliation (Martin & Bergh, 2019). Maryland, Nevada, and Virginia highlight not just the conditions for exerting leadership but also for effective followership. They embraced ambitious statutory GHG emissions reduction targets in the 2020s, but reversals or partisan disputes have constrained the credibility of these steps.
Conclusion
The US states that have joined U2C at different points in time offer numerous instructive insights, which help us to assess the propositions formulated in Chap. 2.
Regarding Proposition 1 (see Chap. 2), U2C founding members have demonstrated the most sustained and diversified climate policy approach. California leveraged its legal waiver and environmental policy legacy to set the pace for policy-based climate action in the United States. The empirical picture for Washington, Oregon, and Vermont also suggests that reputational pressure affected their climate policy effort, though it was not as consistent over time compared to California. Early U2C joiners exhibited similarly uneven empirical patterns in terms of policy- based climate action. Massachusetts and New York expanded existing climate policy frameworks with statutory targets, while Connecticut, Rhode Island, and Minnesota pursued mixed approaches that integrated regional mechanisms like RGGI and finance innovation without always consolidating comprehensive frameworks. New Hampshire represents an early membership example failing to elevate ambition—despite possible reputational damage—due to weak domestic political will. This outcome might be expected from a late joiner, but returning to Proposition 2 (see Chap. 2), reputational costs seem to have proved insufficient to overcome internal political divisions and maintain high climate policy ambition.
Later entrants joined too recently for definitive confirmation, but broadly speaking, their climate policy effort has remained the lowest— though this trend preceded U2C membership. However, Colorado and Hawaii managed to build ambitious climate policy frameworks before joining the coalition. Maine, Maryland, and Nevada show weaker policybased climate action but did align with U2C targets after rebooting their climate policy frameworks. The timing suggests that reputational incentives remained secondary to internal political cycles and shifts in federal politics.
References
Allison, J. E., Press, D., Horowitz, C., Millard-Ball, A., & Pincetl, S. (2016). Chapter 7. Paths to carbon neutrality: Lessons from California. Collabra, 2(1), 1–15. https://doi.org/10.1525/collabra.66
Bedsworth, L. W., & Hanak, E. (2013). Climate policy at the local level. Insights from California,	23(3),	664–677.	https://doi.org/10.1016/j. gloenvcha.2013.02.004
Boyd, B. (2017). Working together on climate change: Policy transfer and convergence in four Canadian provinces. Publius: The Journal of Federalism, 47(4), 546–571. https://doi.org/10.1093/publius/pjx033
Busby, J. W., & Urpelainen, J. (2020). Following the leaders? How to restore progress in global climate governance. Global Environmental Politics, 20(4), 99–121. https://doi.org/10.1162/glep_a_00562
Carlson, A. E. (2008). Iterative federalism and climate change. Journal of Scholarly Perspectives, 4(01), 3–13. https://escholarship.org/uc/item/7pc2n5qc
Dai, F., Yen, E., Gordon, J., Bedsworth, L., Chen, Z., Perron, J., Kahrl, F., & Grignaschi, E. (2020). States’ climate action for achieving carbon neutrality: What’s out there and yet to be done? California–China Climate Institute. https:// ccci.berkeley.edu/sites/default/files/States_Climate_Action_for_Achieving_ Carbon_Neutrality.pdf
duVair, P., Sadler, S., Usibelli, A., & Anderson, S. (2007). West Coast Governors’ Global Warming Initiative: Using regional partnerships to coordinate climate action. In S. C. Moser & L. Dilling (Eds.), Creating a climate for change: Communicating climate change and facilitating social change (pp. 431–450). Cambridge University Press. https://doi.org/10.1017/ CBO9780511535871.030
Governor of Virginia (2024). Governor Glenn Youngkin and Attorney General Jason Miyares: Virginia Will Exit California Electric Vehicle Mandate at End of Year. https://www.governor.virginia.gov/newsroom/news-releases/2024/ june/name-1028520-en.html
Graves, R. A., Haugo, R. D., Holz, A., Pincus-Nielsen, M., Jones, A., Kellogg, B., MacDonald, C., Popper, K., & Schindel, M. (2020). Potential greenhouse gas reductions from Natural Climate Solutions in Oregon, USA. PLoS One, 15(4), 1–30.
Jordan, A., & Huitema, D. (2014). Innovations in climate policy: The politics of invention, diffusion, and evaluation. Environmental Politics, 23(5), 715–734. https://doi.org/10.1080/09644016.2014.923614
Jordan, A., Huitema, D., Asselt, H., & Forster, J. (Eds.). (2018). Governing climate change: Polycentricity in action? Cambridge University Press. https://doi. org/10.1017/9781108284646
Jordan, A., Huitema, D., Hildén, M., van Asselt, H., Rayner, T. J., Schoenefeld, J. J., Tosun, J., Forster, J., & Boasson, E. L. (2015). Emergence of polycentric
climate governance and its future prospects. Nature Climate Change, 5(11), 977–982. https://doi.org/10.1038/nclimate2725
Jotzo, F., Depledge, J., & Winkler, H. (2018). US and international climate policy under President Trump. Climate Policy, 18(7), 813–817. https://doi.org/1 0.1080/14693062.2018.1490051
Karapin, R. (2018). Not Waiting for Washington: Climate Policy Adoption in California and New York. Political Science Quarterly, 133(2), 317–353. https://doi.org/10.1002/polq.12774
Kim, D., & Park, T. J. (2024). Analysis, evaluation and implications of Rhode Island’s “2021 Act on Climate” for response to climate change. Climatic Change, 177(2), 1–19. https://doi.org/10.1007/s10584-024-03680-y
Leffel, B. (2018). Subnational diplomacy, climate governance & Californian global leadership. University of Southern California Center on Public Diplomacy. https://uscpublicdiplomacy.org/sites/uscpublicdiplomacy.org/files/userup- loads/u39301/Subnational%20Diplomacy,%20Climate%20Governance%20 &%20Californian%20Global%20Leadership%20- %20Benjamin%20Leffel_0.pdf
Lorenzen, J. A. (2020). ‘For us climate action never dies’: a legislative process analysis of environmental movement tactics in Oregon. Environmental Sociology, 6(4), 375–389. https://doi.org/10.1080/23251042.2020.1792265
Martin, N., & Bergh, J. C. J. M. (2019). A multi-level climate club with national and sub-national members: Theory and application to US states. Environmental Research Letters,	14(12),	124049.	https://doi.org/10.1088/1748- 9326/ab5045
Masur, J. S. (2022). Regulatory oscillation. Yale Journal on Regulation, 39(2), 744–777. https://chicagounbound.uchicago.edu/journal_articles/10418/
Mazmanian, D. A., & Jurewitz, J. L. (2020). State leadership in US climate change and energy policy: The California experience. The Annals of the American Academy of Political and Social Science, 688(1), 154–175. https://doi. org/10.1177/1070496519887484
McKibben, B. (2019). Don’t burn trees to fight climate change—Let them grow. The New Yorker. https://www.newyorker.com/news/daily- comment/ dont- burn- trees- to- fight- climate- changelet- them- grow
Meckling, J., & Nahm, J. (2018). When do states disrupt industries? Electric cars and the politics of innovation. Review of International Political Economy, 25(4), 505–529. https://doi.org/10.1080/09692290.2018.1434810
Meckling, J., & Nahm, J. (2022). Strategic state capacity: How states counter opposition to climate policy. Comparative Political Studies, 55(3), 493–523. https://doi.org/10.1177/00104140211024308
Meckling, J., & Trachtman, S. (2024). The home state effect: How subnational governments shape climate coalitions. Governance, 37(2), 431–448. https:// doi.org/10.1111/gove.12809
Mildenberger, M. (2021). The development of climate institutions in the United States. Environmental Politics, 30(Suppl. 1), 71–92. https://doi.org/10.108 0/09644016.2021.1947445
Minnesota Pollution Control Agency. (2017, May 9). Adapting to climate change in Minnesota (p-gen4-07c). https://www.pca.state.mn.us/sites/default/files/ p- gen4- 07c.pdf
Nix, P., Goldstein, A., & Oppenheimer, M. (2025). Quasi-governmental organization under pressure: The Connecticut Green Bank’s response to a budget shock. Environmental Policy and Governance, 35(4), 647–661. https://doi. org/10.1002/eet.2161
Perkins, R., & Neumayer, E. (2012). Does the ‘California effect’ operate across borders? Trading- and investing-up in automobile emission standards. Journal of European Public Policy, 19(2), 217–237. https://doi.org/10.108 0/13501763.2011.609725
Portland Press Herald. (2018, January 24). LePage imposes moratorium on new wind energy	permits.	https://www.pressherald.com/2018/01/24/ lepage-i mposes- moratorium- on- new- wind- energy- permits/
Rabe, B. G. (Ed.). (2010). Greenhouse governance: Addressing climate change in America.	Brookings Institution Press. https://www.jstor.org/ stable/10.7864/j.ctt6wpd5x
Roy Chowdhury, P. K., Robertson, J. C., Levin, P. S., Case, M. J., & Brown, D. G. (2025). Opportunities and challenges to community-level adoption of natural climate solutions in Washington State. PLOS Climate, 4(2), 1–23. https://doi.org/10.1371/journal.pclm.0000580
Ruth, M. (2008). Economic and energy impacts from participation in the Regional Greenhouse Gas Initiative: The case of Maryland. Energy Policy, 36(6), 2279–2289. https://www.sciencedirect.com/science/article/abs/pii/ S030142150800133X
Scarcioffolo, A. R., Shakya, S., & Hall, J. C. (2021). The political economy of Vermont’s anti-fracking movement. Journal of Public Finance and Public Choice, 36(1), 49–68. https://doi.org/10.1332/251569120X15814140463976
Selin, H., & Vandeveer, S. D. (2021). Climate politics in the U.S.: Forward, reverse, and through the looking glass. In Climate governance across the globe: Pioneers, leaders and followers (pp. 129–146). Routledge. https://doi.org/1 0.4324/9781003014249- 10
Shields, L. (2023). Greenhouse gas emissions reduction targets and market-based policies. National conference of state legislatures. https://www.ncsl.org/energy/ greenhouse- gas- emissions- reduction- targets- and- market- based- policies
Sovacool, B. K., Gilbert, A., & Thomson, B. (2014). Innovations in energy and climate policy: Lessons from Vermont. Pace Environmental Law Review, 31(3), 651–705.
Sperling, D., & Eggert, A. (2014). California’s climate and energy policy for transportation. Energy Strategy Reviews, 5, 88–94. https://doi.org/10.1016/j. esr.2014.10.001
Tobin, P., Huitema, D., & Kellner, E. (2024). The empirical realities of polycentric climate governance: Introduction to the special issue. Global Environmental Politics, 24(3), 1–23. https://doi.org/10.1162/glep_a_00758

Tosun, J., Heinz-Fischer, C., & Luo, R. (2023). Who takes the lead? A disaggregate analysis of the EU’s engagement in the Clean Energy Ministerial and Mission Innovation. Journal of Cleaner Production, 382, 135240. https://doi. org/10.1016/j.jclepro.2022.135240
Trachtman, S. (2019). Building climate policy in the states. The Annals of the American Academy of Political and Social Science, 685(1), 96–114. https:// doi.org/10.1177/0002716219865173
Union of Concerned Scientists. (2016). Massachusetts’s electricity future. https:// www.ucs.org/sites/default/files/attach/2016/04/massachusetts- electricity- future.pdf
University of Hawaii Economic Research Organization. (2008). Concepts in greenhouse gas regulation: A primer on meeting Act 234. https://uhero.hawaii.edu/ wp- content/uploads/2019/08/ClimateChangePrimer_Oct6.pdf
VanderHart, D. (2025). Oregon lawmakers are now considering a ‘cap- and-trade’ program to fund roads, wildfire prevention. Oregon Public Broadcasting. https://www.opb.org/article/2025/05/22/ oregon-l awmakers- cap- and- trade- program/
Vogel, D. (1995). Trading up: Consumer and environmental regulation in a global economy (1. printing ed.). Harvard Univ. Press.
Wurzel, R. K. W., Liefferink, D., & Torney, D. (2019). Pioneers, leaders and followers in multilevel and polycentric climate governance. Environmental Politics, 28(1), 1–21. https://doi.org/10.1080/09644016.2019.1522033
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CHAPTER 4	
Canada
Abstract This chapter examines climate policy efforts across four Canadian subnational jurisdictions that joined the Under2 Coalition at different timepoints: founding members British Columbia and Ontario, early joiner Québec, and later joiner Northwest Territories. The analysis compares the adoption of climate policy, policy instruments, and greenhouse gas emissions reduction targets to assess whether founding members demonstrate greater climate ambition than subsequent joiners. British Columbia exhibited sustained climate leadership before and after co- founding the Under2 Coalition, while Ontario’s trajectory was marked by political instability and policy reversals. Québec, despite being only an early joiner and not an Under2 Coalition founder, demonstrated robust climate action intertwined with resource nationalism and paradiplomacy. Northwest Territories, as a later joiner, showed limited policy activity but place-specific innovation in addressing energy needs of remote community. The findings reveal that early Under2 Coalition engagement (whether as founding member or early joiner) facilitates maintenance and enhancement of climate leadership, though context-specific factors—including federal-provincial fragmentation, political transitions, and resource dependencies—significantly shape subnational climate action trajectories and climate policy durability.
Keywords Canadian federalism • Climate paradiplomacy • Policy instruments • Political instability • Subnational climate governance
© The Author(s) 2026
J. Tosun et al., Subnational Climate Leadership Dynamics Among Under2 Coalition Members, Palgrave Studies in Sub-National Governance, https://doi.org/10.1007/978-3-032-12610-8_4
Introduction
With regard to its national climate policy, Canada has been described as a laggard (Tobin, 2017). Among other factors, researchers have ascribed this to a resource-driven economy dependent on fossil capital (Tienhaara & Walker, 2021), a tendency to prioritize ambitious rhetoric within international fora over domestic climate action (Winter, 2024), and substantive federal-provincial/territorial fragmentation.
As a highly decentralized federation, Canada grants its provinces—and to a lesser extent territories—considerable jurisdictional autonomy, affording them leeway in their climate policy arrangements (Boyd, 2017; Henstra, 2017). Meanwhile, there is also substantial overlap between federal and provincial authority, which has created some ambiguity and perpetuated a variegated landscape of subnational climate action (Giest & Howlett, 2013), encapsulated by contrasting engagement with U2C.
Building on multilevel governance literature, this chapter probes Liefferink and Wurzel’s (2017; see also Chap. 2) four ideal types of subnational climate leadership to examine the extent to which founding signatories of U2C (British Columbia and Ontario) have demonstrated more climate policy effort than subnational counterparts that joined earlier (Québec) and later (Northwest Territories).
Founding Members
British Columbia
British Columbia has cultivated ambitious climate policy since 2007— with some labeling it the only carbon neutral jurisdiction in North America (Giest & Howlett, 2013)—and has been described as an “unlikely climate policy vanguard” (Fairbrother & Rhodes, 2023) due to four factors.
First, while existing literature suggests regions with substantive fossil fuel industries generally exhibit low climate ambition (Lamb & Minx, 2020), British Columbia displays high climate ambition despite being a significant fossil fuel “producer” (Fairbrother & Rhodes, 2023, p. 2).
Second, despite possessing subnational competencies to act on climate change, British Columbia stepped up climate ambitions within a (relatively) unsupportive provincial political context: some of its most prominent early climate policies (including the carbon tax) were enacted by a right-of-center Liberal government (Fairbrother & Rhodes, 2023).
Third, while decarbonizing electricity generation is an important route to GHG emissions reduction for many subnational governments, British Columbia has historically depended on renewable energy sources (e.g., hydroelectric dams) to generate electricity. Unlike other jurisdictions, British Columbia has been unable to draw on this (relatively) low effort means of stepping up climate action.
Finally, British Columbia is a major gasoline consumer: transportation emissions dominate GHG emissions portfolios, while a provincial lightduty vehicle fleet has been described as “one of the world’s least fuelefficient” (Fairbrother & Rhodes, 2023, p. 3). Meanwhile, commentators often lament US-Canada gasoline prices (due to significantly lower US prices), making regressive measures increasing vehicle fuel taxes contentious.
Despite operating within this (relatively) unfavorable context, British Columbia has exhibited substantive climate ambitions (Boyd, 2017), as we will see in the remainder of this chapter.
Ontario
Ontarian climate policy predates U2C and is shaped by several contextspecific factors, including—but not limited to—its status as a key petroleum refining region/financial hub and its substantive population (about 40% of the national total). Ontarian municipalities are also creatures of the province: they have limited autonomy and must replicate provincial climate policy decisions.
Existing literature distinguishes three phases of Ontarian climate policymaking: (1) a 2001–2014 coal phase-out propelled by campaigns for improved air quality; (2) a 2006–2013 feed-in-tariff program centered around promoting greater use of renewable energy sources; and (3) a 2008–2018 cap-and-trade program and associated climate policy retrenchment (Millar et al., 2021). These phases have produced climate policies of variable traction, underscoring the context-specific nature of climate ambition.
First, in 2001, Ontario legislated closure of the Lakeview coal station because of concerns over air quality and electricity supply (Jones, 2014; Millar et al., 2021). In 2003, a newly elected Liberal Government formalized the closure of all power stations by 2007. While this phase-out was postponed twice, it was delivered in 2014. This landmark contribution to Canada’s Kyoto Protocol commitments has been attributed to a salient public health framing that justifies closure in terms of “public health benefits: cleaner air from reduced local pollutants associated with fossil fuels, rather than a focus on climate change” (Raymond, 2020, p. 1130).
Second, in 2006, Ontario introduced a feed-in-tariff to subsidize low- carbon technologies via long-term contracts designed to create investor certainty, promote innovative renewable energy projects, and reduce prices.
Third, in 2008, the Liberal Government initiated a cap-and-trade policy, but was unable to realize this until 2017 (Millar et al., 2021). In 2018, Ontario joined a cap-and-trade scheme in collaboration with California and Québec, signaling a brief period of U2C-affialiated cross-border collaboration.
However, Ontario rapidly withdrew from this initiative. While it was initially skillfully framed by Liberals as economically beneficial (any revenue would be reinvested to improve the energy efficiency of public infrastructure), when the Progressive Conservatives came to power in 2018, they denounced the program as an affront to “working Ontarians” and as a “slush fund” to finance a fanciful liberal wish list (Raymond, 2020, p. 1134).
In summary, Ontario adopted a range of climate policy measures before and after co-founding U2C; these were shaped by context-specific factors including the rise and decline of political administrations.
Early Joiner
Québec
Existing literature describes Québec as having developed “an important web of actions, commitments and cooperative efforts” which transcend borders, span governance levels, and predate U2C participation (Chaloux & Boudreau, 2025, p. 264). Participation in U2C, which Québec joined in 2015 shortly after it was founded, represents a continuation of these diverse activities.
Through early advocacy (since the 1970s) on issues including acid rain, chlorofluorocarbons, and water management, Québec has used climate policy to foster interprovincial and international ties (Boyd, 2017; Teare, 2012). This is epitomized by early collaboration with New England states in the United States in the framework of the NEG-ECP (Selin & Vandeveer, 2005; see also Chap. 3). Chaloux et al. (2022, p. 267) examine Québec’s decades-long efforts to establish itself as an “autonomous paradiplomatic actor in the global climate regime”. They outline how Québec has stepped up its climate ambition through paradiplomacy—acts through which actors project “themselves globally to find support for initiatives, offering expertise and sharing best practices, sometimes to protect their own interests, but more often to gain positive international exposure that reflects well domestically” (Chaloux et al., 2022, p. 268). Québec has joined a range of international initiatives alongside U2C, including Regions4. In 2016, Québec declared itself an autonomous participant of the Paris Agreement to the UNFCCC (Chaloux, 2016). Engagement with these initiatives reflects a desire to accelerate the proliferation of provincial climate “policies, plans and measures” (Chaloux et al., 2022, p. 269).
Nonetheless, various other contextual factors have shaped Québec’s climate policy effort. Key among these is substantive renewable energy capacities (e.g., hydroelectricity and mineral endowments) and the absence of any major oil or gas industry. Its plural electoral system and unicameral legislature marked by majority governments historically advocating contrasting political ideologies (Lemphers et al., 2022)—combined with its cultural distinctiveness (a French-speaking majority), nationalist sentiments, and long-standing Gérin-Lajoie doctrine, which asserts that “what Québec is competent to do within its borders, it is also competent to do beyond its borders” (McSweeney & Ouellet, 2025, p. 164)—have shaped its foreign policy objectives, often in favor of climate action. Another significant factor is Québec’s history of effective grassroots campaigning against extractivist proposals prior to U2C formation.
Later Joiner
Northwest Territories
The existing literature synthesizes endemic factors shaping Northwest Territories climate policy. These include (1) a legacy of federal involvement in territorial governance through “spending powers and control of residual policy areas” (though devolution has ceded more autonomy over time); (2) a regional economy dominated by natural resource extraction (diamond mining and oil and gas extraction constitute about 25% of territorial Gross Domestic Product); (3) public administration, construction, and real estate as significant local economic sectors; (4) a bipartite electricity system, comprising a Thermal and Hydro Zone; and (5) a population of about 44,000, of which approximately half consider themselves Indigenous. Notably, many remote Indigenous communities rely on diesel as a heating/electricity source, while two communities—Inuvik and Norman Wells—are “electrified via natural gas” (Mallett & Cherniak, 2018, pp. 1326–1327).
Moreover, Northwest Territories have effectively linked climate policy to other salient local issues, namely, territorial autonomy. This facilitated the (successful) pursual of climate policy innovation through unconventional modes of generating, transmitting, and distributing electricity. The Northwest Territories have further been described as an “open opportunity structure” where climate policy entrepreneurship could thrive despite the dominance of conventional electricity generation (Mallett & Cherniak, 2018, p. 1333).
In summary, Northwest Territories’ climate policy is shaped by contextspecific factors including a legacy of federal governance, resourcedependent economy, significant Indigenous population, and geographically specific opportunity structure. These factors have shaped a unique territorial climate policy approach vis-à-vis subnational counterparts.
Comparative Analysis
Policies
British Columbia expanded its climate policies prior to co-founding U2C, while Ontario significantly expanded its climate policies shortly afterwards. In contrast, Québec and Northwest Territories, as early and later joiners respectively, exhibited notable activity in issuing various climate plans before and after joining U2C, while their enactment of climate policies remained (relatively) low even after joining the coalition (especially for Northwest Territories). In short, these findings (partially) support the central proposition of this volume formulated in Chap. 2 that founding members face stronger reputational incentives to adopt more ambitious climate measures than later joining subnational counterparts. However, they also suggest that being an early joiner matters, too.
The findings additionally suggest that U2C membership can be leveraged to maintain and step up subnational climate ambitions, but that membership is less consequential for the legal codification of climate policy than softer measures, including climate plan adoption. Early and later joiners even exhibit more activity in terms of plan creation compared to U2C co-founders (see Fig. 4.1). The following subsection expands on these findings by comparing the climate policy adoption of British Columbia and Ontario vis-à-vis Québec and Northwest Territories.

Fig. 4.1 Adoption of climate laws and plans

Figure 4.1 demonstrates how U2C founding members—British Columbia and Ontario—adopted more climate legislation than early and later joiners. However, Québec and Northwest Territories have been especially active in issuing various climate plans and have even exceeded founding members in terms of policy activity. The remainder of this subsection will examine each subnational entity in detail.
In 2007, British Columbia adopted the GHG Reductions Target Act, signaling the first concerted effort by the provincial Liberal Party to legislate climate action and marking a wider shift in the adoption of climate laws. In 2016, shortly after co-founding U2C, British Columbia implemented the GHG Industrial Reporting and Control Act. It also approved a Pacific NorthWest Liquid Natural Gas (LNG) project and updated its Climate Leadership Plan (which expounds a series of sector-specific commitments to reduce GHG emissions).
In 2021, the CleanBC Roadmap to 2030 was published, building on the wider CleanBC program (which won an U2C award for being the most creative climate policy solution to have emerged from the coalition as of 2021). The new roadmap also facilitated the creation of several specific climate policies, including the 2021 Hydrogen Strategy, the 2022
Low Carbon Fuels Act, and the 2022 Climate Preparedness and Adaptation Strategy.
In short, British Columbia demonstrated relatively consistent climate policy activity—through early policy action, progressive but contested initiatives like LNG development, and an expanding CleanBC framework that won U2C recognition.
In contrast, Ontario’s climate policy trajectory has been shaped by political instability, with significant early innovations dismantled. As such, Ontarian climate policy activity reveals the susceptibility of subnational climate ambition to political instability and demonstrates the (potential) benefits of U2C membership in counteracting these effects. Early administrations (e.g., that of Dalton McGuinty) failed to implement a crosssectoral approach to climate policy, partly due to a lack of formal processes and procedures to coordinate policy initiatives across ministries in Ontario’s Westminster-based parliamentary system (Jones, 2014).
Nonetheless, the Liberal Government retained majority control of the Ontarian government for eight years, introducing: (1) the Places to Grow Act (2005), (2) Greenbelt Act (2005), and (3) a 2006 feed-in-tariff for renewable energy production (see section “Founding Members”).
In 2009, Ontario legislated the Green Energy and Green Economy Act (GEGEA), framing it as an “economic development policy” that would grow the local renewables sector (Raymond, 2020, p. 1130). This act expanded the feed-in-tariff by raising subsidies: by 2011, Ontario had signed about 5500 MW of wind energy contracts.
However, the GEGEA was dismantled in 2013 by a newly elected Liberal Government: voters “punished” the incumbent government due to perceived (economic) harm to local communities (Stokes, 2016). Elements of the feed-in tariff, including the removal of municipal control on the siting process, allowed policy opponents to create significant resistance to the policy (Millar et al., 2021).
While Ontario adopted more climate policies shortly after co-founding U2C in 2015 (see Fig. 4.1), climate policy development stagnated following the 2018 election of the Progressive Conservatives. Ontario’s cap- and- trade scheme was repealed, about 750 renewable energy projects were canceled, and the GEGEA was removed entirely (which, in essence, made it more difficult to implement new renewable energy projects). In their place—and following the IPCC’s 2018 Special Report on Global Warming of 1.5C—a Made-in-Ontario Environment Plan was published. However, the plan does not stipulate action in the transportation sector, even though this is a major source of Ontarian GHG emissions. Consequently, in 2019, Ontario’s Auditor General said that the state’s 2030 emissions reduction targets were unobtainable.
In 2024, Ontario published an Affordable Energy Future plan, accompanied by a telling ministerial message describing it as “a pro-growth agenda” rather than ideological dogma at the expense of workers and businesses (Ministry of Energy and Mines Ontario, 2024).
Overall, Ontario adopted various climate policies with variable traction. Several policies were adopted prior to co-founding U2C, while others were adopted afterward. Ontarian climate policy has been notably shaped by political instability, which led to the dismantling of several innovative initiatives (e.g., the GEGEA) adopted after co-founding U2C.
Despite (only) being an early joiner of U2C, Québec adopted its first climate plan in 2001, followed by updates in 2006, 2013, and 2015. After joining U2C in 2015—and serving as North American co-chair 2015–2018—Québec adopted (among other policies) the ZEV Act, a 2030 Plan for a Green Economy, and a refreshed Northern Action Plan 2023–2028.
However, existing literature provides important nuance. Fopa Tchinda and Talbot (2025) uncovered a lack of policy coherence which has constrained Québec climate policy implementation across successive plans. Beigi and Picard (2025) connected the dominance of flagship organizations like Hydro-Québec—a publicly owned electricity utility—to the retrenchment of resource nationalism, in this instance, resource extraction to facilitate state-building.
Consequently, by using decarbonization to pursue state-building, Québec climate policy has continued, rather than departed from, “the province’s pursuit of extractive growth and accumulation” (Beigi & Picard, 2025, p. 16). Climate policy developments—ranging from the 2011 Plan Nord to the Sustainable Mobility Plan 2030—arguably entrench dependencies on “intensive hydroelectric production, mineral extraction and large-scale battery production” (Beigi & Picard, 2025, p. 16).
While Québec has stepped up climate ambitions, it has neglected to integrate diverse voices, including environmental NGOs and Indigenous peoples, into the policymaking process (Chaloux et al., 2015).
Overall, Québec adopted multiple climate policies. While several were adopted prior to joining U2C, several more specific policies (e.g., on ZEVs and sustainable mobility) were adopted after joining. However, by prioritizing state-building, these policies arguably intensify Québec’s legacy of resource extractivism and reify power asymmetries.
To this end, Québec’s U2C participation reflects a growing path dependency (centered around large infrastructure clean energy projects), intensification of (inter)national climate commitments, and growing commitment to climate paradiplomacy. The presence of a range of complex, interlocking contextual factors shaping climate ambitions makes it difficult to discern the extent to which U2C membership has had a singular influence on Québec’s climate policy ambitions.
As a later joiner, Northwest Territories adopted the fewest laws but the most climate plans. Beginning in 2001, Northwest Territories published a series of Greenhouse Gas Strategies covering 2001–2015. Notably, these climate policies prioritized corporate over jurisdiction-wide emissions.
Following a 2012 Energy Charrette, Northwest Territories released an Energy Plan, pivoting from reactive energy management toward proactive investment in renewables (e.g., hydro, solar, biomass), to reduce reliance on diesel in off-grid communities, increase support for energy efficiency initiatives across residential, commercial, and government sectors, and strengthen partnerships with Indigenous governments and local communities in energy planning and delivery. The plan also stipulated support for solar photovoltaic installations in remote communities (e.g., Colville Lake), expansion of biomass heating systems in public buildings, and ongoing support for Arctic Energy Alliance-affiliated programs.
In 2016, Northwest Territories adopted the Pan-Canadian Framework on Clean Growth and Climate Change (PCF), a federal government-led initiative designed to align subnational actors with the Paris Agreement. While the framework was designed to introduce a degree of equivalency across Canadian jurisdictions (Mascher, 2018), it has been critiqued as a top- down governance solution which reinscribes asymmetric settler-colonial relations, violates Indigenous rights, and systematically excludes Indigenous peoples (Reed et al., 2021).
In 2018, Northwest Territories published a 2030 Energy Strategy and a Climate Change Strategic Framework, setting ambitious goals to reduce diesel usage in remote communities. A 2022–2025 Energy Action Plan then outlined actions and investments needed to meet the goals of the 2030 Energy Strategy, including projects to enhance renewable energy deployment, improve energy efficiency, and support clean transportation. Finally, in 2023, Northwest Territories became the second Canadian
jurisdiction (after British Columbia) to enact the UN Declaration on the Rights of Indigenous Peoples Implementation Act.
In short, Québec and Northwest Territories, as early and later U2C joiners, respectively, adopted a range of climate policies which predate U2C membership. Québec pursued ambitious climate planning since 2001 and later intensified its action through major hydroelectric and mineral extraction projects, reflecting path-dependent resource nationalism. Its U2C membership coincided with expanded paradiplomacy and the enactment of numerous sector-specific policies. In contrast, Northwest Territories climate policy evolved through community-focused energy strategies aimed at reducing diesel reliance and enhancing autonomy. The adoption of plans after joining U2C amplified its focus on renewables, Indigenous collaboration, and rights-based frameworks. While Northwest Territories had adopted GHG emissions reduction strategies before joining U2C, the jurisdiction-wide policies it adopted afterward were notably more ambitious.
Policy Instruments
This subsection compares similarities and differences between the climate policy instruments adopted by each subnational actor (see Fig. 4.2).

Fig. 4.2 Policy instruments to reduce regional GHG emissions
British Columbia introduced three notable policy instruments via their 2008 climate plan: (1) a Carbon Tax; (2) a Clean Energy Standard (or CES, which banned coal-fired electricity generation and required 90% of new electricity generation to come from zero-emission sources); and (3) a 2010 Low Carbon Fuel Standard (which stipulated Renewable and Low Carbon Fuel Requirements; Fairbrother & Rhodes, 2023).
The 2008 carbon tax was designed to reduce fossil fuel consumption. However, it was repealed in 2025 because of a (political) desire to prioritize economic recovery.
The CES, conversely, was particularly consequential and immediately resulted in the cancelation of new coal-fired and gas-fired electricity plants, making it one of the most impactful policies at that time (Fairbrother & Rhodes, 2023).
Similarly, British Columbia increased Low Carbon Fuel Standard stringency over time by widening its scope (e.g., introducing carbon intensity reduction requirements for jet fuels, starting at 2% in 2026 and increasing to 10% in 2030) and by enhancing reductions targets (e.g., in 2022, British Columbia amended the 2030 reduction target from 20 to 30% below 2010 levels by 2030).
Since co-founding U2C, British Columbia has introduced a suite of other policy instruments, including a 2018 Better Buildings energy efficiency program, a 2019 CleanBC Industry Fund, and a 2019–2024 Industrial Incentive Program.
Ontario has adopted various policy measures to reduce GHG emissions. Of these, several (e.g., coal phase-out, feed-in-tariff, and ZEV uptake measures) were implemented before co-founding U2C, while others (e.g., a cap-and-trade scheme) were adopted after.
Between 2006 and 2007, Ontario adopted a feed-in-tariff to support renewable energy development, introduced MoveOntario 2020 to increase public transport usage, and created a Next Generation Jobs Fund to promote low-carbon industry growth.
To promote EV uptake, Ontario introduced an Incentive Program in 2010 to support and reward early adopters of EVs and to stimulate market demand (Erutku, 2020). This initial scheme was further bolstered in 2016 and 2018.
Meanwhile, Ontario adopted a cap-and-trade scheme in 2017 after joining U2C. However, the rapid repeal of this instrument (see section “Founding Members”) underscores the salience of economic framings in determining the longevity of climate policy instruments despite the historic prioritization of climate action (Young et al., 2022).
Despite joining U2C shortly after it was founded, Québec adopted a variety of climate policy instruments (Chaloux & Boudreau, 2025).
In 2007, Québec became one of the first North American subnational actors to introduce a carbon levy and, in 2013, co-created a carbon market with California by integrating and harmonizing two pre-existing cap-and- trade programs (Boyd, 2017). This established the first “multisectoral carbon market in North America, and the second most important carbon market in the world after the European Union” (Chaloux, 2016). In 2017, Québec and California furthered collaborative ambitions by legislating greater transparency and deeper integration of the program, in accordance with the Paris Agreement. Québec retained the scheme in 2025 despite widespread subnational repeals following the termination of a Federal Consumer Carbon Tax, underscoring the importance of transboundary collaboration within an otherwise unsupportive national policy context.
In 2016, after joining U2C, Québec stepped up activity on transportation electrification, becoming the first province to adopt a ZEV uptake mandate (Aubertin et al., 2024). Lemphers et al. (2022, p. 9) suggest the agency of subnational climate policy actors was crucial to securing this mandate without a major provincial automotive industry.
Northwest Territories introduced a limited number of policy instruments before joining U2C, including a Capital Asset Retrofit Fund to improve the energy efficiency of government-owned buildings and an Arctic Energy Alliance to provide jurisdiction-wide energy efficiency education, technical support, and funding. Meanwhile, a 2012 Energy Charette—a territory-wide, multi-stakeholder consultation process— established broad consensus on the need to transition away from fossil fuel energy dependencies (e.g., diesel in remote communities).
In 2017, Northwest Territories introduced a Buildings and Industry grant to encourage commercial and industrial sectors to invest in energy efficiency upgrades and/or energy systems. Similarly, in 2018, an additional GHG grant program was introduced, offering funding for clean energy projects and/or retrofits of publicly owned infrastructure.
The PCF—designed to help fulfill Canada’s commitments under the Paris Agreement—stipulated the introduction of a pan-Canadian carbon price by the end of 2018 (c.f. Mascher, 2018). However, in recognition of the various carbon pricing initiatives already in place across Canada, provinces and territories were granted flexibility to adopt either a carbon tax, cap-and-trade, or hybrid system. In 2019, Northwest Territories opted for a carbon tax on fuels, starting at $20 per ton and increasing annually to $50 per ton. There were some exemptions to this tax: aviation fuel was excluded, residents/small businesses received a 100% rebate for any heating fuel, and a Cost-of-Living Offset was introduced to reduce residential impacts. To align with changes in national-level carbon pricing policies, the tax was repealed for all consumers except large emitters in 2025.
Finally, in 2022, Northwest Territories emulated other U2C members by introducing a ZEV measure to support the installation of related infra- structure—an initiative championed by U2C.
In summary, all four regions implemented various policy instruments to reduce GHG emissions. Québec and British Columbia were early adopters of a carbon tax (in 2007 and 2008, respectively). Notably, Québec expanded its carbon market in collaboration with California in 2013. Ontario was the second of the four jurisdictions to create a cap-and-trade system in 2017 (however, this was repealed after just one year). All actors granted various subsidies early on to promote more climate-friendly behaviors. British Columbia and Ontario have most actively implemented regulatory measures, especially standards for transport, energy generation, and energy efficiency in buildings. All four jurisdictions generally implemented only a limited number of informational or voluntary policy measures. Finally, British Columbia and Québec led on information and training measures since early on.
Targets
All four subnational entities adopted GHG emissions reduction targets with various time frames: short, medium, or long term (see Fig. 4.3). Short- and medium-term targets are generally considered to be the most ambitious as they put immediate pressure on policymakers to take climate action.
The findings suggest that co-founders of U2C do not necessarily adopt more ambitious (short-term) climate targets than early and later joiners: while British Columbia adopted a short-term target prior to co-founding U2C, Ontario did not, and both have since refrained from adopting such targets. Similarly, while Québec adopted a short-term target prior to

Fig. 4.3 Greenhouse gas emissions reduction targets
joining the coalition, Northwest Territories adopted a short-term target in 2018 after joining U2C.
Significantly, British Columbia and Ontario committed to long-term GHG emissions reduction prior to participating in U2C, while Québec and Northwest Territories adopted long-term targets after joining the coalition.
Québec and British Columbia were the first of the four regions to adopt net-zero targets in 2020 and 2021, respectively, followed by Northwest Territories in 2024.
In short, the findings are mixed: they suggest co-founders of U2C do not necessarily adopt more ambitious climate targets than early and/or later joiners. While U2C membership might in some instances (e.g., Northwest Territories) support target-setting, this activity appears to be largely context-specific and a substantive political achievement. This might go some way to explaining the uniformity in the adoption of (comparatively less contentious) long-term targets, whereby co-founders adopted these targets prior to creating the coalition and other states adopted these targets after joining it.
Leadership
The analysis revealed varied and evolving yet fragile modes of subnational climate leadership associated with U2C membership.
In line with the existing literature (c.f. Dale et al., 2020), British Columbia exhibited climate leadership before and after co-founding U2C, adopting various climate policies, instruments, and targets, including a landmark 2008 carbon tax. While substantial renewable energy capacities and devolved competencies facilitated structural leadership, co-founding U2C provided a valuable opportunity to maintain and step up climate ambitions within a (broadly) unsupportive national context. However, examples of (contested) entrepreneurial and cognitive leadership were also identified, including efforts to articulate a “progressive extractivism” storyline to legitimize LNG industry development (Chen, 2020). While proponents of LNG framed it as symbolically “cleaner” than other “dirtier” energy sources (e.g., coal, oil; Chen & Gunster, 2016), opponents highlighted its potential to ossify power inequities and extractive ideologies. Similarly, British Columbia repealed its carbon tax in 2025. In summary, while U2C membership provided an opportunity to maintain leadership credentials, it did not fundamentally alter the contested, context-specific nature of climate action.
Ontario’s climate leadership was marked by political instability. For example, cognitive leadership is inherent in Ontario’s early coal phase-out framed around public health benefits. Its feed-in-tariff program and 2009 GEGEA signaled further cognitive and entrepreneurial leadership through efforts to rebrand Ontario as a “green leader” (Nishimura, 2012; Stokes, 2016). However, Ontario’s cap-and-trade scheme was repealed shortly after co-founding U2C, amid public backlash following its depiction as a blight to working Ontarians. In short, Ontario illustrates how while cofounding U2C can (seemingly) create strong reputational incentives to maintain climate ambitions, climate leadership remains vulnerable to context- specific factors (e.g., adversarial politics).
Québec exhibited climate leadership despite (only) being an early joiner. Early ratification of a carbon levy and co-creation of a cap-and- trade system (with California) situated Québec as leading on collaborative, transboundary governance. A 2016 ZEV mandate further demonstrated instrumental leadership on transportation electrification. Nonetheless, Québec’s climate ambitions are intertwined with resource nationalism: state-led hydroelectric and mineral extraction projects bolstered statebuilding aspirations that prioritize resource accumulation over participatory policymaking. In short, Québec exemplifies how while climate leadership can step up ambition, it can also reinscribe inequities.
Despite being a later joiner and (largely) resembling a climate follower (e.g., on legislative and instrument adoption) facing weaker reputational incentives, Northwest Territories exhibited some leadership traits. Contextual factors (e.g., remote communities) necessitated innovative climate action distinct from more industrialized provinces. Consequently, Northwest Territories used cognitive leadership to integrate climate action into salient local issues and thereby step up climate action (e.g., territorial autonomy). Despite exhibiting less policy activity than U2C co-founders and (largely) exhibiting followership, Northwest Territories has begun to exercise place-specific leadership, seemingly facilitated primarily by U2C membership.
Overall, British Columbia, Québec, and Ontario exhibited sustained leadership despite variable temporal engagement with U2C. While Northwest Territories was less prolific, it has (seemingly) used U2C to step up its climate ambitions, recently demonstrating cognitive leadership by integrating climate action into salient local issues. In short, these findings suggest that early engagement with U2C (either as a founding member or early joiner) facilitates the maintenance and/or enhancement of climate leadership, and while there is limited difference between founding members and early joiners, both actors (broadly) demonstrate more ambitious climate activities than later joiners. However, they also reveal the diverse, context-specific manifestations of subnational climate leadership.
Conclusion
This chapter has explicated the modes of leadership and followership exhibited by two U2C co-founders compared to one early and one later joiner, with reference to the existing literature on subnational climate action and a novel synthesis of the climate policies, instruments, and targets adopted before and after joining the coalition.
The analysis reveals that Canadian subnational climate policy often stems from a combination of national-level leadership vacuum and placespecific contextual factors. All four subnational actors have engaged with U2C to varying degrees, but the extent to which their involvement marked a change in their modes of leadership and/or followership varies.
The findings suggest that, facing strong reputational incentives, U2C co-founders leveraged the coalition to maintain and enhance subnational climate ambitions, which often predated the coalition. Meanwhile, in the absence of national-level climate leadership, Québec (as an early joiner) appears to have used it as an opportunity to consolidate more established ambitions centered around climate paradiplomacy, and the Northwest Territories (as a later joiner) appear to have used it to emulate subnational counterparts. Thus, the temporality of U2C membership, and ensuing strength of reputational incentives, (seemingly) matters. Nonetheless, analysis also revealed how the adoption and repeal of ambitious climate measures is susceptible to context-specific changes within individual jurisdictions, exemplified by the widespread diminution of cap-and-trade measures in 2025.
Even so, it remains difficult to prove definitively that U2C membership has a singular influence on subnational climate action: while the Canadian case suggests that early and later joiners may well emulate best practice solutions of founding members, it is also feasible that these actors gravitate toward the same/similar policy solutions independent of U2C participation, and that the increased density of policy measures is merely emblematic of the wider proliferation of substate climate ambitions post Paris. In short, more in-depth process tracing analysis is warranted to examine why, how, and to what effect different actors engage with U2C over time (i.e., the mechanisms of reputational motivation) as well as with any other climate clubs. This would enable researchers to more closely examine their implications for subnational climate leadership and followership.
References
Aubertin, A., Axsen, J., & Gunster, S. (2024). Electric vehicles for climate, a green economy, or independence? Comparing policy discourse in newspapers across three Canadian provinces. Energy Research & Social Science, 108, 103353. https://doi.org/10.1016/j.erss.2023.103353
Beigi, T., & Picard, M. (2025). Three waves of resource nationalism: A history of Quebec’s extractive path dependency. Environmental Politics, 1–21. https:// doi.org/10.1080/09644016.2025.2502245
Boyd, B. (2017). Working together on climate change: Policy transfer and convergence in four Canadian provinces. Publius: The Journal of Federalism, 47(4), 546-571. https://doi.org/10.1093/publius/pjx033
Chaloux, A. (2016). Vingt-Cinq Ans De Paradiplomatie Climatique Québécoise: Quel Bilan Pour L’Action Internationale du Québéc? Revue québécoise de droit international/Quebec Journal of International Law/Revista quebequense de derecho internacional, 81–98. https://doi.org/10.7202/1067650ar
Chaloux, A., & Boudreau, J. (2025). 20 Years of climate paradiplomacy between Québec and the United States. In F. Gagnon, C. Kirkey, & S. Paquin (Eds.), The Québec-United States relationship: Political, security, economic, environmental and cultural dynamics (pp. 263–284). Springer Nature Switzerland. https://doi.org/10.1007/978- 3- 031- 76113- 3_11
Chaloux, A., Paquin, S., & Séguin, H. (2015). Canada’s multiple voices diplomacy in climate change negotiations: A focus on Québec. https://doi.org/10.116 3/15718069- 12341311
Chaloux, A., Séguin, H., & Simard, P. (2022). “All in” climate regime: Federated states as autonomous participants to the Paris Agreement the cases of Québec and California. Canadian Foreign Policy Journal, 28(3), 265–284. https://doi. org/10.1080/11926422.2021.2002702
Chen, S. (2020). Debating resource-driven development: A comparative analysis of media coverage on the Pacific Northwest LNG project in British Columbia. Frontiers in Communication, 5. https://doi.org/10.3389/fcomm.2020.00066
Chen, S., & Gunster, S. (2016). “Ethereal carbon”: Legitimizing liquefied natural gas in British Columbia. Environmental Communication, 10(3), 305–321. https://doi.org/10.1080/17524032.2015.1133435
Dale, A., Robinson, J., King, L., Burch, S., Newell, R., Shaw, A., & Jost, F. (2020). Meeting the climate change challenge: Local government climate action in British Columbia, Canada. Climate Policy, 20(7), 866–880. https://doi.org/1 0.1080/14693062.2019.1651244
Erutku, C. (2020). A first look at Ontario’s electric vehicle incentive program: Who are Ontario’s green drivers? Canadian Public Policy, 46(1), 37–44. https://doi.org/10.3138/cpp.2019- 014
Fairbrother, M., & Rhodes, E. (2023). Climate policy in British Columbia: An unexpected journey. Frontiers in Climate, 4. https://doi.org/10.3389/ fclim.2022.1043672
Fopa Tchinda, A., & Talbot, D. (2025). The quest for coherence in climate actions: The case for Québec’s Climate strategy. Environmental Policy and Governance, 35, 682–695. https://doi.org/10.1002/eet.2164
Giest, S., & Howlett, M. (2013). Comparative climate change governance: Lessons from European transnational municipal network management efforts. Environmental Policy and Governance, 23(6), 341–353. https://doi. org/10.1002/eet.1628
Henstra, D. (2017). Climate adaptation in Canada: Governing a complex policy regime. Review of Policy Research, 34(3), 378–399. https://doi.org/10.1111/ ropr.12236
Jones, S. (2014). Flirting with climate change: A comparative policy analysis of subnational governments in Canada and Australia. Journal of Comparative Policy Analysis: Research and Practice, 16(5), 424–440. https://doi.org/1 0.1080/13876988.2014.942570
Lamb, W. F., & Minx, J. C. (2020). The political economy of national climate policy: Architectures of constraint and a typology of countries. Energy Research & Social Science, 64, 101429. https://doi.org/10.1016/j.erss.2020.101429
Lemphers, N., Bernstein, S., Hoffmann, M., & Wolfe, D. A. (2022). Rooted in place: Regional innovation, assets, and the politics of electric vehicle leadership in California, Norway, and Québec. Energy Research & Social Science, 87, 102462. https://doi.org/10.1016/j.erss.2021.102462
Liefferink, D., & Wurzel, R. K. W. (2017). Environmental leaders and pioneers: Agents of change? Journal of European Public Policy, 24(7), 951–968. https:// doi.org/10.1080/13501763.2016.1161657
Mallett, A., & Cherniak, D. (2018). Views from above: Policy entrepreneurship and climate policy change on electricity in the Canadian Arctic. Regional Environmental Change, 18(5), 1323–1336. https://doi.org/10.1007/ s10113- 018- 1317- 7
Mascher, S. (2018). Striving for equivalency across the Alberta, British Columbia, Ontario and Québec carbon pricing systems: The Pan-Canadian carbon pricing benchmark. Climate Policy, 18(8), 1012–1027. https://doi.org/10.108 0/14693062.2018.1470489
McSweeney, P., & Ouellet, R. (2025). Between charm offensives and confrontations: A brief portrait of the defense of Québec’s commercial interests before American authorities. In F. Gagnon, C. Kirkey, & S. Paquin (Eds.), The Québec- United States relationship: political, security, economic, environmental and cultural dynamics (pp. 161–187). Springer Nature Switzerland. https://doi. org/10.1007/978- 3- 031- 76113- 3_7
Millar, H., Bourgeois, E., Bernstein, S., & Hoffmann, M. (2021). Self-reinforcing and self-undermining feedbacks in subnational climate policy implementation. Environmental Politics, 30(5), 791–810. https://doi.org/10.1080/0964401 6.2020.1825302
Ministry of Energy and Mines Ontario. (2024). Ontario’s affordable energy future: The pressing case for more power | ontario.ca. http://www.ontario.ca/page/ ontarios- affordable- energy- future- pressing- case- more- power
Nishimura, K. (2012). Grassroots action for renewable energy: How did Ontario succeed in the implementation of a feed-in tariff system? Energy, Sustainability and Society, 2(1), 6. https://doi.org/10.1186/2192- 0567- 2- 6
Raymond, L. (2020). Carbon pricing and economic populism: The case of Ontario. Climate Policy, 20(9), 1127–1140. https://doi.org/10.108 0/14693062.2020.1782824
Reed, G., Gobby, J., Sinclair, R., Ivey, R., & Matthews, H. D. (2021). Indigenizing climate policy in Canada: A critical examination of the Pan-Canadian framework and the ZéN RoadMap. Frontiers in Sustainable Cities, 3. https://doi. org/10.3389/frsc.2021.644675
Selin, H., & Vandeveer, S. D. (2005). Canadian-U.S. environmental cooperation: Climate change networks and regional action. American Review of Canadian Studies, 35(2), 353–378. https://doi.org/10.1080/02722010509481376
Stokes, L. C. (2016). Electoral backlash against climate policy: A natural experiment on retrospective voting and local resistance to public policy. American Journal of Political Science, 60(4), 958–974. https://doi.org/10.1111/ ajps.12220
Teare, R. (2012). Two birds with one stone: The political and environmental motives of Quebec’s climate change policy. Federalism-E, 13(1) Article 1. https://doi.org/10.24908/fede.v13i1.13596
Tienhaara, K., & Walker, J. (2021). Fossil capital, ‘unquantifiable risk’ and neoliberal nationalizations: The case of the Trans Mountain Pipeline in Canada. Geoforum,	124,	120–131.	https://doi.org/10.1016/j. geoforum.2021.06.005
Tobin, P. (2017). Leaders and laggards: Climate policy ambition in developed states. Global Environmental Politics, 17(4), 28–47. https://doi.org/10.1162/ GLEP_a_00433
Winter, J. (2024). Exploring the landscape of Canadian climate policy. Canadian Public Policy, 50(S1), 73–102. https://doi.org/10.3138/cpp.2023- 055
Young, K. M., Gurganus, K., & Raymond, L. (2022). Framing market-based versus regulatory climate policies: A comparative analysis. Review of Policy Research, 39(6), 798–819. https://doi.org/10.1111/ropr.12493
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CHAPTER 5	
Germany
Abstract This chapter examines climate policy efforts across eight German states that joined the Under2 Coalition at different timepoints, analyzing founding member Baden-Württemberg, five early joiners (Bavaria, Hesse, North Rhine-Westphalia, Schleswig-Holstein, and Thuringia), and two later joiners (Lower Saxony and Rhineland-Palatinate). Operating within Germany’s concurrent legislation principle that constrains subnational regulatory autonomy, these states demonstrate varied climate policy and leadership trajectories shaped by the federal energy transition (Energiewende), political configurations, and structural conditions. Baden- Württemberg emerges as the most consistent climate leader, exhibiting cognitive, exemplary, structural, and entrepreneurial leadership through early legislative action, a comprehensive set of policy instruments, and sustained ambition before and after co-founding the Under2 Coalition. Early joiners show mixed patterns: North Rhine-Westphalia initially demonstrated strong leadership before changes in government weakened ambition, while Schleswig- Holstein leveraged structural advantages and Bavaria remained a follower despite early membership. Later joiners present contrasting cases, with Rhineland-Palatinate exhibiting unexpected climate leadership and Lower Saxony remaining a follower despite renewable energy advantages. The analysis reveals that Under2 Coalition membership reinforced leadership where favorable state-level conditions existed—particularly Green Party government participation—while having limited impact on laggard states.

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© The Author(s) 2026
J. Tosun et al., Subnational Climate Leadership Dynamics Among Under2 Coalition Members, Palgrave Studies in Sub-National
Governance, https://doi.org/10.1007/978-3-032-12610-8_5
Keywords Coalition government • Concurrent legislation • Energiewende (energy transition) • German federalism • Subnational climate leadership
Introduction
The German states have played a significant part in reducing GHG emissions in Germany, although to varying extents. Some have been strong leaders, while others have been reluctant laggards (Eckersley et al., 2023). In principle, the German states are entitled to adopt their own climate legislation, although the so-called concurrent legislation principle limits their ability to introduce new regulations if concurrent regulations have already been adopted by the federal government (Eckersley et al., 2023). Consequently, most legislative decisions on German climate policy are made at the federal and EU levels (Jänicke & Wurzel, 2019). In particular, the federal Energy Transition (Energiewende) strategy to replace fossil and nuclear energy generation with renewable energies, introduced in 1998 and reinforced in 2011 after the Fukushima nuclear accident, has had a strong influence on the policy-based climate action of German states (Eckersley et al., 2023; Joas et al., 2016; Steuwer & Hertin, 2020; Von Hirschhausen, 2014).
Nonetheless, even the limited freedom of the German states to pass their own climate legislation provides them with the opportunity to assume leadership within the EU’s multilevel governance system (Irepoglu Carreras, 2019). For instance, the federal Climate Change Act allows German states to adopt their own climate change acts, or the federal Renewable Energy Heat Act allows the states to define their own regulations for older buildings. In these cases, the German states can be even more ambitious than the federal government (Eckersley et al., 2023). Moreover, the German states are responsible for implementing most federal climate policies, which gives them leeway in how effectively they put these into practice (Behnke, 2020; Eckersley et al., 2023).
This chapter sheds light on subnational climate leadership, examining the extent to which Baden-Württemberg, as a founding signatory of U2C, has adopted more ambitious climate policies compared to the five states that joined early (Bavaria, Hesse, North Rhine-Westphalia, Schleswig- Holstein, Thuringia) and the two states that joined later (Lower Saxony and Rhineland-Palatinate).
Founding Member
Baden-Württemberg
Baden-Württemberg has long been recognized as a leader in subnational climate policy in Germany. Even before co-founding U2C in 2015, the state had begun developing a unique climate policy framework that combined climate legislation, sectoral strategies, and innovative policy instruments.
Baden-Württemberg was governed by Christian Democratic Union (CDU) led governments for 58 consecutive years until 2011, when the first elections were held since the Fukushima incident. This event had triggered an intense debate on nuclear energy in Germany, particularly in Baden-Württemberg, which was strongly dependent on nuclear energy at the time. Traditionally a strong proponent of nuclear energy, the CDU lost out to the anti-nuclear Green Party (Beveridge & Kern, 2013). The subsequent change in government, with the election of a Green Party Minister President, further propelled the state’s climate ambition (Jahn & Korolczuk, 2012; Schneider, 2025; Wurster, 2017). The new coalition government of the Greens and the Social Democratic Party (SPD) promised to realign energy with climate protection and did not fail to deliver: it adopted one of Germany’s first climate protection laws with legally binding GHG emissions reduction targets in 2013, followed by a series of strategy papers and action plans with specific policy instruments (Jacob & Kannen, 2015). Baden-Württemberg, as one of the co-founding members of U2C, exemplifies how subnational states and regions can demonstrate climate leadership. The state government has dubbed itself the “California of Germany”, fostering technical innovation in climate mitigation and advancing climate policy while also consciously pursuing a climate leadership role within Germany as a whole (Walker, 2021).
Early Joiners
Bavaria
Similar to Baden-Württemberg, Bavaria was heavily dependent on nuclear electricity generation. Therefore, the state was under great pressure to transition to renewable energies in the 2010s, following the federal nuclear power phase-out. Consequently, Bavaria has made significant progress on solar energy; however, this progress can largely be traced back to federal policies rather than to climate policies adopted by the state government itself (Eckersley et al., 2023).
Hesse
Before joining U2C in 2015, Hesse was already a leader in environmental policy. In 2008, it became one of the first German states to adopt a sustainability strategy involving climate change mitigation. Unlike Baden- Württemberg or Bavaria, Hesse did not rely on nuclear energy generation and therefore faced less political pressure to promote renewable energies. The absence of a large fossil fuel sector also made it easier for Hesse to advance ambitious climate action (Eckersley et al., 2021, 2023).
North Rhine-Westphalia
North Rhine-Westphalia was an unlikely climate leader given its heavy reliance on coal for electricity generation and its large industrial sector. In 2013, the state became the first in Germany to pass a climate protection law. Early success in reducing GHG emissions has been difficult to maintain (Eckersley et al., 2021).
Schleswig-Holstein
Schleswig-Holstein was an early leader in Germany’s transition to renewable energy sources. This is mainly due to its long coastlines on the North Sea and the Baltic Sea, as well as favorable conditions for wind power, which has been the state’s main priority for climate policy (Eckersley et al., 2021, 2023).
Thuringia
Thuringia is the only state in the Eastern part to have joined U2C and adopted a climate protection law with legally binding emissions reduction targets (in 2018). The state has been especially active in supporting renewable energy sources. Its ambition to transition to renewable energy has been bolstered by its historically low dependency on coal (Eckersley et al., 2021, 2023).
Later Joiners
Lower Saxony
Lower Saxony joined U2C in 2017. Similar to Schleswig-Holstein, the state has been a leader in transitioning to renewable energy sources thanks to its coastal location on the North Sea and favorable conditions for wind power (Monstadt & Scheiner, 2016). As early as 2015, over 40 percent of gross electricity generation in Lower Saxony came from renewable energy sources (Eckersley et al., 2023). However, the fossil fuel sector, especially oil, has played a more prominent role in Lower Saxony than in Schleswig-Holstein.
Rhineland-Palatinate
Rhineland-Palatinate is the second later-joining state in Germany. In 2017, it joined U2C under a state government of the CDU, SPD, and Greens, with a Green environmental minister in office. Much like Hesse and Thuringia, Rhineland-Palatinate did not rely on its own coal and nuclear energy plants. Instead, it depended on energy imports, which facilitated the promotion of renewable energies (Eckersley et al., 2021). Rhineland- Palatinate is unique in that it is composed of many small municipalities (fewer than 2000 inhabitants), which lack the resources necessary for effective climate action (Eckersley et al., 2023). For this reason, supporting municipalities has been a priority of the state’s climate policy.
Comparative Analysis
The following section compares climate action (policies, instruments, and targets adoption) of Baden-Württemberg with that of the states that joined early: Bavaria, Hesse, North Rhine-Westphalia, Schleswig-Holstein, and Thuringia. Then it turns to the states that joined later: Rhineland- Palatinate and Lower Saxony.
Policies
Founding Member: Baden-Württemberg
Baden-Württemberg clearly stands out in terms of the number of climate policies adopted (see Fig. 5.1). The state government’s first policies date

Fig. 5.1 Adoption of climate policies

to 1994, when it adopted a climate protection concept. This initial concept primarily focused on raising awareness and providing advisory services (Jacob & Kannen, 2015). The state maintained its leadership by implementing the Climate Protection-Plus funding program in 2002, publishing an updated Climate Protection Concept in 2005, and adopting the Renewable Heat Act in 2008. The latter imposed a legal obligation on homeowners to use renewable heat sources in existing and newly built houses. This legislation surpassed federal regulations in both scope and ambition (Jacob & Kannen, 2015).
Alongside North Rhine-Westphalia, Baden-Württemberg was one of the first German states to adopt a Climate Protection Law in 2013, which imposed a legally binding obligation to significantly reduce GHG emissions in the short and long term. This law was supplemented by an Integrated Energy and Climate Protection Concept detailing strategies and measures for achieving the state’s climate goals (Jacob & Kannen, 2015).
Since then, Baden-Württemberg revised its 2008 Renewable Heat Act and adopted an updated Climate Protection and Climate Change Adaptation Act in 2023. The state government also implemented several climate policy instruments as part of various sector-specific strategies and concept papers. Examples include a Freight Transport Concept and a Charging Infrastructure Strategy in 2020, a Public Transport Strategy in 2022, a Waste Management Plan, and an updated Energy Concept in 2024. In short, Baden-Württemberg took a leading role early on, demonstrating consistent policy activity marked by early policy-based climate action, sector-specific climate plans, and instruments. These developments support our proposition that founding members of U2C adopt more ambitious climate policies (see Chap. 2).
Early Joiners: Bavaria, Hesse, North Rhine-Westphalia, Schleswig-Holstein, and Thuringia
Similar to Baden-Württemberg, Bavaria’s climate policies date to 2000, when it adopted its first climate protection program. However, unlike Baden-Württemberg, Bavaria had less subsequent climate policy activity, and the activity that took place was strongly associated with federal requirements to transition from nuclear to renewable energies (Eckersley et al., 2023; Goers et al., 2020). A key policy for this transition was the 2011 Bavarian Energy Concept.
The state published several updates of its climate protection program in 2009, 2015, and 2019. The 2015 update marked the first time that Bavaria defined quantifiable GHG emissions reduction targets (Goers et al., 2020). The 2019 update, titled the Climate Protection Offensive, focused on energy and outlined detailed objectives and a comprehensive set of climate policy instruments (Eckersley et al., 2021). As an early joiner of U2C, however, Bavaria was late to enshrine GHG emissions reduction targets into law, adopting its Climate Protection Law only in 2020. Despite its relatively late adoption, the law is no more ambitious than the earlier climate protection acts adopted by other German states. In 2024, Bavaria issued a Heating Strategy and an updated Climate Protection Program.
In short, despite being an early joiner to the coalition and having a longer history of climate policies, Bavaria did not present itself as a strong climate leader before or after joining U2C.
Hesse similarly had several climate policies in place before joining U2C in 2015. These included a climate protection concept, adopted in 2007, and a Sustainability Strategy, published in 2008. The state government updated the Sustainability Strategy several times: in 2014, 2016, and 2020. A central piece of Hesse’s climate policy is the Hessian Energy Future Act, adopted in 2012. This act provides financial incentives to invest in energy efficiency and renewable energy sources. In fact, Hesse has been particularly active in supporting municipalities in their climate action efforts, introducing a major funding program in 2016 through the Hessian Municipal Energy Guideline (Eckersley et al., 2023). The state further adopted several strategies and action plans, including an Integrated Climate Protection Plan in 2017, a transportation mobility strategy, and, most recently, an updated climate plan in 2023. Like Bavaria, Hesse was slow to adopt a climate protection law with legally binding emissions reduction targets. The state did not adopt the Hessian Climate Act until 2023.
Overall, Hesse has promoted climate protection, both before and after joining U2C. The state has done so primarily by supporting municipalities. However, the state has not been as active in pursuing climate policies as Baden-Württemberg.
Despite its heavy reliance on coal for electricity generation and a large industrial sector, North Rhine-Westphalia was an early climate leader in Germany. In the early 2000s, the state adopted several climate plans, including the Climate Protection Concept in 2001, the Energy and Climate Protection Strategy in 2008, and the Climate Protection Start Program in 2011. The latter included substantial funding for energyefficient building renovations (Eckersley et al., 2021). In 2013, North Rhine-Westphalia adopted the first comprehensive climate protection law in Germany, which included legally binding GHG emissions reduction targets and a comprehensive sustainability strategy (Eckersley et al., 2021, 2023). In 2021, the law was revised to include a carbon neutrality target, and in 2024, it was complemented by a State Heat Planning Act on energy efficiency.
North Rhine-Westphalia further developed several action plans, including a Climate Protection Plan in 2015, an Energy Supply Strategy in 2019, and Climate Protection Packages in 2023 and 2025. These plans include specific instruments, such as substantial funding programs to promote energy efficiency, renewable energy sources, investments in hydrogen infrastructure, and the transition to “green” industries. Despite these efforts, North Rhine-Westphalia has not become as strong a climate leader as Baden-Württemberg since joining U2C, in terms of both policy activity and expanding renewable energies and reducing GHG emissions. Scholars have attributed this to the change in government from a SPD-Green coalition to a center-right coalition of CDU and Free Democratic Party in 2017 (Eckersley et al., 2021, 2023).
In short, North Rhine-Westphalia was an early climate leader despite its comparatively less favorable conditions; however, since the founding of U2C, it has not kept up with Baden-Württemberg.
Before joining U2C, Schleswig-Holstein was already a climate leader among the German states. This is particularly true for the transition to renewable energies, in particular the expansion of wind power. The state government’s first climate policy dates to 1992, when it published an Energy Concept aimed at phasing out nuclear energy and expanding renewable energy sources, mainly wind and biomass. In 1995, the state government introduced a Mitigation and Climate Protection Program encompassing policy instruments to reduce GHG emissions from energy generation, buildings, transportation, agriculture, and forestry. Several plans and programs were implemented prior to joining U2C, including a Sustainability Strategy in 2004, a Climate Protection Action Program in 2008, an ambitious Integrated Energy and Climate Concept in 2011, which included the goal of transitioning completely to renewable energies by 2015, and a Strategy for Electromobility in 2014 (Eckersley et al., 2021).
After joining the coalition, Schleswig-Holstein adopted an Energy Transition and Climate Protection Law, enshrining short-, medium-, and long-term GHG emissions reduction targets into state law. Apart from providing a legal basis for expanding renewable energies, the law introduced standards to enhance energy efficiency in non-residential buildings (Eckersley et al., 2021). Subsequent state governments published plans and programs detailing how Schleswig-Holstein aims to achieve its emissions reduction targets. These include the Climate Protection Program 2030 (2019), the Strategy on Achieving the Climate Targets (2020), and the Implementation Agreement on Decarbonization of Electricity and Heat Generation (between the state and energy and water providers in Schleswig-Holstein).
Overall, Schleswig-Holstein has been a climate leader in Germany since the early 2000s. The state enshrined its climate aspirations in ambitious, comprehensive GHG emissions reduction targets and made significant progress, particularly in expanding renewable energy sources. Its climate leadership before and after joining U2C is evident through its continued high level of policy activity, even if it falls short of Baden-Württemberg’s.
Thuringia long lagged behind the other early-joining states in terms of climate ambition (Eckersley et al., 2021). Despite this, it developed climate mitigation plans early on, including the strategy paper Climate Protection in Thuringia (2000), which includes a medium-term GHG emissions reduction target; the Energy and Climate Strategy Thuringia 2015 (2009), which aimed to expand renewable energies and improve energy efficiency in buildings and transportation; and the Sustainability Strategy (2011). After joining U2C, Thuringia significantly advanced its climate ambitions by adopting a Climate Protection Law in 2018. Through this law, the state committed to ambitious medium- and long-term GHG emissions reduction targets and to regularly updating climate strategies. In 2019, Thuringia published the Integrated Energy and Climate Protection Strategy, which describes specific policy instruments aimed at reducing emissions from transport, agriculture, and land use (Eckersley et al., 2021). Thuringia was particularly active in 2024 when several state departments published individual sustainability plans. That same year, Thuringia adopted the Wind Energy Participation Act, which aims to increase acceptance of wind turbines at the local level by providing municipalities with opportunities to participate financially in wind power projects.
In short, Thuringia’s climate action has not matched that of other early-joining states. The 2018 climate protection law and its associated climate action plan significantly increased the state’s climate ambition. Despite this progress, Thuringia has been a climate follower rather than a leader.
Later Joiners: Lower Saxony and Rhineland-Palatinate
Despite its leadership in renewable energies, particularly wind power and bioenergy, Lower Saxony has lagged behind other German U2C signatories in terms of overall climate policy activity. Before joining the network in 2017, Lower Saxony adopted several climate plans, including the Climate Protection Action Plan in 2000, the Bioenergy Offensive Lower Saxony in 2002 (a campaign to educate the public about bioenergy technology), the Sustainability Strategy in 2008, and the Climate Policy Implementation Strategy in 2013. Lower Saxony did not adopt a Climate Protection Act until 2020, three years after joining U2C. The act, adopted by a CDU-SPD state government, commits Lower Saxony to significantly reducing its GHG emissions in the long term and promoting renewable energies. However, it neglects other sectors, such as agriculture and transportation. Consequently, the act was strongly criticized, especially by the Green Party and the German Association for the Environment and Nature Conservation, for not being ambitious enough (Eckersley et al., 2021). In later years, Lower Saxony published two more climate protection strategies, in 2022 and 2025. The most recent strategy, adopted by an SPD- Green coalition government, includes more ambitious targets and specific policy instruments to promote renewable energy and energy efficiency in buildings, as well as increased funding.
Overall, Lower Saxony has been a follower rather than a climate leader, despite its pioneering role in renewable energy and its recent increase in climate ambition. Although the state published climate strategies early on, policy activity remained comparatively low for a long time, neglecting major GHG emitting sectors other than electricity generation.
In contrast, the state of Rhineland-Palatinate demonstrated significant policy activity, even compared to the states that joined early on. The state was particularly active in developing several sustainability strategies that incorporated climate mitigation (in 2001, 2003, 2005, 2007, 2011, 2015, and 2019). Rhineland-Palatinate has been a leader among the other German states in this regard (Eckersley et al., 2021).
Rhineland-Palatinate was the third German state, after Baden- Württemberg and North Rhine-Westphalia, to adopt a comprehensive Climate Protection Act in 2014, which included legally binding GHG emissions reduction targets (Eckersley et al., 2021, 2023). Since then, the law was supplemented by several action plans and programs, including the 2015 Climate Protection Concept, which offered suggestions for specific policy measures; the 2017 Heating Concept; the updated 2020 Climate Protection Concept; and the 4+1 Strategy, which aims to achieve climate neutrality in state-owned properties by 2030. In 2021, Rhineland- Palatinate adopted the State Law on the Installation of Solar Systems, which includes a legal obligation for new commercial buildings and larger parking lots to have photovoltaic systems installed.
In 2025, the state government revised its Climate Protection Law to include carbon neutrality and interim GHG emissions reduction targets that are to be achieved by 2035. Compared to the initial legislation, the new Climate Protection Law is not just an ambitious framework policy but also a legally binding control instrument with specific targets, a monitoring system, sectoral commitments, economic incentives, and a strong focus on carbon sequestration through the Climate Forest Initiative.
Overall, Rhineland-Palatinate has been a climate leader among the German states, despite joining U2C later. The state’s climate policies became more ambitious, especially since the Green Party joined the coalition government in 2021 and took charge of the state ministry of climate protection, the environment, energy, and mobility.
Policy Instruments
Figure 5.2 illustrates noteworthy differences and similarities among German states in their selection of policy instruments to reduce GHG emissions.
Founding Member: Baden-Württemberg
Over time, Baden-Württemberg implemented a comprehensive mix of climate policy instruments. It is one of the few states that implemented a carbon tax in 2023 for new, state-owned buildings in the form of a carbon shadow price. Baden-Württemberg also provided financial incentives from the early 2000s, including subsidies for the energy-efficient renovation of buildings. In 2021, the state government introduced e-Solar vouchers to promote solar-powered mobility solutions and incentives for forest protection and peatland regeneration.
The state government defined several notable standards since 2007, mostly with the aim of enhancing energy efficiency in buildings and increasing renewable energy generation. Regarding the latter, in 2022 it introduced an obligation to install photovoltaic systems in new buildings. Baden-Württemberg also stands out for its extensive information and training services. It established the Climate Protection and Energy Agency Baden-Württemberg as early as 1994. Since then, the state added several other services to support municipalities and enhance the development and application of new transportation technologies. Recently, the state government pushed for voluntary agreements with businesses by initiating the

Fig. 5.2 Policy instruments to reduce regional GHG emissions

Climate Alliance Baden-Württemberg in 2022. Through this alliance, businesses commit to specific climate protection measures and targets.
Early Joiners: Bavaria, Hesse, North Rhine-Westphalia,
Schleswig-Holstein, and Thuringia
Bavaria implemented relatively few specific policy instruments. Other than Baden-Württemberg, it did not adopted a carbon pricing scheme. Between 2015 and 2022, Bavaria offered financial incentives for energy-efficient home renovations but has since neglected to provide any similar statewide subsidies. The state implemented a funding program for job bike leasing in 2023, which is the only transportation subsidy. Notably, in 2022, Bavaria introduced an obligation for non-state actors to install photovoltaic systems on roofs. Voluntary agreements with businesses have played a prominent role in Bavaria for years. Established in 2004 with environmental groups, the Bavarian Climate Alliance encourages its members to engage in climate-friendly behavior. However, these agreements have not included specific measures or targets, as they have in Baden-Württemberg. Two institutions, the Bavarian Energy Agencies and LandSchafftEnergie, were established in 2013 to provide information on the energy transition.
Hesse also implemented a smaller set of specific policy instruments compared to Baden-Württemberg. The instruments it adopted, however, have broad implications. For example, Hesse introduced an obligation to install photovoltaic systems in large parking lots and state-owned buildings as part of the 2012 Hessian Energy Futures Act. The same legislation also provides financial incentives for improving energy efficiency in buildings and installing renewable energy technologies. The state has generously supported municipalities in Hesse for pursuing climate measures in several areas since 2016. Moreover, Hesse has actively supported the provision of information and training services, especially in the realms of energy efficiency and renewable energies, through an energy agency it established in 1991.
North Rhine-Westphalia implemented fewer and less varied concrete climate policy instruments than Baden-Württemberg. However, the state has a strong track record of providing financial incentives to municipalities, citizens, and businesses, dating to the late 1980s. One major funding program, initiated in 1987, provided financial support for over 50,000 renewable energy projects until 2006. This program continued in 2008 and still supports renewable energy projects today. Additionally, North Rhine-Westphalia has heavily subsidized energy-efficient building renovations since 2011. Another program, Low Emission Mobility, which began in 2018, covers up to 80% of municipalities’ expenses for EVs, bikes, and charging infrastructure (Eckersley et al., 2021). An obligation to install photovoltaic systems on parking lots and newly constructed buildings was introduced most recently in 2024. The state has also provided information and training services through an energy agency established in 1990 and a competence center for energy-efficient heating (Eckersley et al., 2021).
Schleswig-Holstein’s ambitious climate strategies have been translated into a comprehensive mix of specific policy measures; however, unlike Baden-Württemberg (and North Rhine-Westphalia), they were implemented much later. The state first introduced large-scale financial incentives in 2018 to support energy community projects. In 2020, the state began providing financial incentives for municipalities to undertake energy-efficient building renovations. Since 2017, the state also defined standards for the heating and energy efficiency of buildings. This came after its establishment from 2014 onward of various information services on energy efficiency, low-emission mobility, and climate-friendly agriculture.
Thuringia implemented a notable number of specific policy instruments despite not being as active in pursuing climate policies as most other early joiners of U2C in Germany. Thuringia established a set of funding programs to provide financial incentives for projects on energy efficiency, renewable energies, and transport comparatively early, in 2015. Additionally, the state defined standards for energy-efficient buildings in 2019 and for wind power in 2024. Like most other German U2C signatories, Thuringia has offered information and training services through a state-owned climate agency since 2011.
In sum, all the states that joined early implemented fewer or less comprehensive policy instruments than Baden-Württemberg. Furthermore, the extent to which these states implemented such measures varies. Within this group, North Rhine-Westphalia and Hesse led the way, followed by Schleswig-Holstein and Thuringia. In contrast, Bavaria clearly lagged behind.
Later Joiners: Lower Saxony and Rhineland-Palatinate
Lower Saxony developed a comprehensive mix of policy instruments, though these have only been implemented in recent years. They include a 2020 implemented subsidy program for battery storage to accelerate the adoption of photovoltaic installations. The state also invested in e- mobility, local transportation, and bike paths in the same period. The climate protection law adopted in 2020 and its associated program of measures further define several energy efficiency standards for buildings, including the obligation to install photovoltaic technologies in car parks and on newly constructed buildings, as well as the obligation to purchase emission-free rail vehicles for state use. Similar to Baden-Württemberg, Lower Saxony implemented a carbon shadow price for its state administration purchases. Since 2014, a climate protection and energy agency has provided information and training services.
Most of Rhineland-Palatinate’s specific climate instruments wereimple- mented more recently, following the change in government in 2021. These instruments include a carbon shadow price on state-owned buildings and an obligation to install photovoltaic systems in parking lots and on new buildings. Earlier instruments include providing municipalities with financial support to enhance energy-efficient heating and increase the use of renewable energies (Eckersley et al., 2021).
To summarize, both later-joining states implemented fewer specific climate instruments than Baden-Württemberg and the states that joined early (except for Bavaria). They also implemented these instruments later in time.
Targets
All eight German states adopted GHG emissions reduction targets with medium- and long-term time frames. Some of them—Hesse, Lower Saxony, and Schleswig-Holstein—also defined short-term targets. See Fig. 5.3 for an overview.
Baden-Württemberg was the first state to legally define medium- and long-term GHG emissions reduction targets in its 2013 Climate Protection

Fig. 5.3 GHG emissions reduction targets
Act (Jacob & Kannen, 2015). This further indicates its role as the climate leader among the German states.
Most of the states that joined early, except for Thuringia, defined climate targets only after signing the U2C MoU. North Rhine-Westphalia, Hesse, Schleswig-Holstein, and Thuringia adopted medium-term targets earlier than Bavaria, which coincides with the differences in policy activity described previously. Rhineland-Palatinate adopted a target relatively early for a state that joined later, whereas Lower Saxony did not do so until 2020.
Unlike the other types of targets, differences in adopting long-term targets cannot be clearly attributed to the status of early- and later-joining U2C members. This may be because long-term targets are a weaker indicator of climate ambition as they do not immediately pressure policymakers into taking action (Gadani et al., 2020).
Leadership
Baden-Württemberg clearly stands out as the clearest and most consistent climate leader among the German states. Long before co-founding U2C, the state pioneered climate policy with early legislative action, most prominently a climate protection law in 2013 which was followed by sectorspecific climate plans and policy instruments. Baden-Württemberg hereby exhibited cognitive leadership, introducing policy innovations that shaped the subsequent policy-based climate action of other states to join U2C. In addition, the state’s early policy activity revealed exemplary leadership, offering transferable solutions to other states. After co-founding U2C in 2015, Baden-Württemberg sustained momentum by revising legislation, updating climate strategies across different sectors, and developing an encompassing mix of policy instruments. Co-founding U2C itself exhibits a form of entrepreneurial leadership, as the state actively engaged in encouraging other subnational entities to interact and advance policybased climate action. Finally, Baden-Württemberg’s comparative affluence enabled it to invest more heavily in climate protection, underscoring its role as a structural climate leader. The combination of technical developments, structural pressures from the nuclear phase-out, and sustained Green Party leadership without decisive political transitions clearly reinforced Baden-Württemberg’s role as a climate frontrunner.
Other early joiners of U2C show more varied patterns. North Rhine- Westphalia, historically dependent on coal and characterized by a large
manufacturing sector, initially defied expectations by passing Germany’s first comprehensive climate protection law in 2013, which served as a model for many other German states. This demonstrated cognitive and exemplary leadership, two years before it joined U2C. However, subsequent political shifts—most notably the 2017 replacement of a SPD- Green government with a center-right coalition—reduced the state’s ambition and highlighted how weakening factors, such as changes in government in combination with economic pressures, can disrupt leadership trajectories.
Schleswig-Holstein, benefiting from favorable wind conditions, showed consistent structural leadership by leveraging geographical advantages to expand renewable energies. Albeit not to the same extent as Baden- Württemberg, Schleswig-Holstein continuously adopted climate policies before and after joining U2C, thereby exhibiting a form of exemplary leadership. In contrast to Baden-Württemberg and North Rhine- Westphalia, it took Schleswig-Holstein longer to implement an encompassing mix of specific policy instruments, particularly with regards to other sources of GHG emissions than energy generation, which is characteristic of followership rather than leadership.
Hesse represents a more ambivalent case of leadership. The state took climate action early on, particularly by supporting municipalities in their ambition to enhance energy efficiency and expand renewable energies, which constitutes a type of exemplary leadership. Nonetheless, Hesse lagged behind the other climate leaders in terms of overall policy activity and specific policy instruments.
Thuringia can be described as a case of delayed leadership. The state has caught up only recently with other German U2C signatories in respect of policy activity and the introduction of a comprehensive set of policy instruments, illustrating that it has been a follower rather than a leader. Nevertheless, given its weaker economic power, Thuringia exhibited exemplary leadership among the Eastern German states.
Bavaria, despite having a longer history of climate policy and being an early joiner of U2C, lagged behind and largely followed other states. Its lack of leadership is evident from its comparatively low policy activity, its late codifying of binding GHG emissions reduction targets, and its enactment of very few specific policy instruments. A weakening factor to Bavaria’s climate leadership was the absence of a green party in government. Bavaria is unique among German states in being governed continuously by the conservative Christian Social Union, whether as a single party or leading coalition governments.
The two later joiners of U2C provide an equally mixed picture of climate leadership. Lower Saxony, despite being a pioneer in wind energy, did not translate this into comprehensive climate action. Policy activity remained comparatively low and the state’s climate law, adopted only in 2020, was criticized for insufficient ambition, suggesting that structural advantages alone are insufficient without strong political ambition. The 2017 change from an SPD-Green to an SPD-CDU government weakened the state’s climate leadership aspirations. Overall, in terms of climate policy, Lower Saxony is best described as a follower.
Rhineland-Palatinate, in contrast, was surprisingly active for a later- joining U2C signatory. Its 2014 Climate Protection Act positioned it alongside Baden-Württemberg and North Rhine-Westphalia as an early legislative leader, which is indicative of cognitive and exemplary leadership. The change in government in 2021 to a coalition with the Green Party as a partner had a strengthening effect on Rhineland-Palatinate’s climate leadership in recent years.
Taken together, the empirical analysis of German states’ climate action confirms Chap. 2’s proposition that leadership is dynamic and shaped by both strengthening and weakening forces. Strengthening factors—such as the federal nuclear phase-out in combination with heavy reliance on nuclear energy, falling renewable energy costs, and Green Party participation in state governments—propelled leadership in several states. Weakening factors, including fossil fuel dependence, political transitions, and economic pressures, curtailed ambition in others, as seen in North Rhine-Westphalia and Lower Saxony. U2C membership appears to have reinforced leadership where favorable domestic contexts already existed, but it was less decisive in encouraging laggard states to take stronger action.
Conclusion
This chapter has examined the diverse trajectories of climate leadership and followership among the German states that joined U2C. The findings reveal that German subnational climate action has been shaped by both structural conditions and political contexts, which is in line with existing literature (Eckersley et al., 2021, 2023). Baden-Württemberg, as a founding member, consistently demonstrated strong and multifaceted leadership, rooted in early policy action, sector-specific strategies, and comprehensive policy instruments. Its leadership trajectory underscores how U2C engagement reinforced, rather than initiated, its existent ambitions. Among early joiners, states such as North Rhine-Westphalia and Schleswig-Holstein also displayed elements of leadership, though their trajectories were constrained by reliance on coal or lower structural pressures for green transition. Bavaria and Thuringia, in contrast, exhibited weaker and more hesitant leadership. Later joiners provide a similarly mixed picture: Rhineland-Palatinate emerged as a proactive legislator, while Lower Saxony, despite structural advantages, remained a follower. Changes in government influenced climate trajectories in both states.
Taken together, the analysis suggests that U2C membership reinforced leadership where favorable domestic conditions already existed—such as political ambition, often signified by Green Party participation in government, or structural pressures from the nuclear phase-out—while having a weaker impact on laggard states. At the same time, the persistence or retreat of climate leadership has been highly sensitive to political transitions and economic pressures, exemplifying the contingent nature of subnational climate action.
References
Behnke, N. (2020). Administrative autonomy of the German Länder over seven decades of the Basic Law. In F. Knüpling, M. Kölling, S. Kropp, & H. Scheller (Eds.), Reformbaustelle Bundesstaat (pp. 187–202). Springer Fachmedien Wiesbaden. https://doi.org/10.1007/978- 3- 658- 31237- 4_12
Beveridge, R., & Kern, K. (2013). The Energiewende in Germany: Background, developments and future challenges. Renewable Energy Law and Policy Review, 4(1), 3–12.
Eckersley, P., Kern, K., Haupt, W., & Müller, H. (2021). The multi-level context for local climate governance in Germany: The role of the federal states (No. 3; IRS Dialog). Leibniz-Institut für Raumbezogene Sozialforschung (IRS). https:// www.econstor.eu/bitstream/10419/237056/1/1765950244.pdf
Eckersley, P., Kern, K., Haupt, W., & Müller, H. (2023). Climate governance and federalism in Germany. In A. Fenna, S. Jodoin, & J. Setzer (Eds.), Climate governance and federalism: A Forum of federations comparative policy analysis (1st ed., pp. 150–176). Cambridge University Press. https://doi. org/10.1017/9781009249676
Gadani, G., Galarraga, I., & Sainz De Murieta, E. (2020). Regional climate change policies: An analysis of commitments, policy instruments and targets. Economics and Policy of Energy and the Environment, 2, 49–74. https://doi.org/10.3280/ EFE2019- 002003
Goers, S., Rumohr, F., Fendt, S., Gosselin, L., Jannuzzi, G. M., Gomes, R. D. M., Sousa, S. M. S., & Wolvers, R. (2020). The role of renewable energy in regional energy transitions: An aggregate qualitative analysis for the partner regions Bavaria, Georgia, Québec, São Paulo, Shandong, Upper Austria, and Western Cape. Sustainability 2021, 13(76), 1–30.
Irepoglu, C. Y. (2019). Problem‐Solving Across Literatures: Comparative Federalism and Multi‐Level Governance in Climate Change Action. European Policy Analysis, 5(1), 117-134. https://doi.org/10.1002/epa2.2019.5.issue-1 10.1002/epa2.1066
Jacob, K., & Kannen, H. (2015). Integrated strategies for climate policy integration and coherence: The case of Germany (pp. 1–25). Forschungszentrum für Umweltpolitik. Freie Universität Berlin. ISSN 1612-3026.
Jahn, D., & Korolczuk, S. (2012). German exceptionalism: The end of nuclear energy in Germany! Environmental Politics, 21(1), 159–164. https://doi. org/10.1080/09644016.2011.643374
Jänicke, M., & Wurzel, R. K. W. (2019). Leadership and lesson-drawing in the European Union’s multilevel climate governance system. Environmental Politics, 28(1), 22–42. https://doi.org/10.1080/09644016.2019.1522019
Joas, F., Pahle, M., Flachsland, C., & Joas, A. (2016). Which goals are driving the Energiewende? Making sense of the German energy transformation. Energy Policy, 95, 42–51. https://doi.org/10.1016/j.enpol.2016.04.003
Monstadt, J., & Scheiner, S. (2016). The federal states in national energy and climate policy: Spatial distribution effects and federal policy-making for the energy transition [Die Bundesländer in der nationalen Energie- und Klimapolitik: Räumliche Verteilungswirkungen und föderale Politikgestaltung der Energiewende]. Raumforschung Und Raumordnung | Spatial Research and Planning, 74(3). https://doi.org/10.1007/s13147- 016- 0395- 6
Schneider, V. (2025). Germany’s energy and climate policy as an ecology of games. Politics and Governance, 13, 10023. https://doi.org/10.17645/pag.10023
Steuwer, S., & Hertin, J. (2020). Climate policy in Germany: Pioneering a complex transformation process. In R. K. W. Wurzel, M. S. Andersen, & P. Tobin (Eds.), Climate governance across the globe: Pioneers, leaders and followers (1st ed., pp. 160–181). Routledge. https://doi.org/10.4324/9781003014249
Von Hirschhausen, C. (2014). The German “Energiewende”—An introduction. Economics of Energy & Environmental Policy, 3(2). https://doi.org/10.554 7/2160- 5890.3.2.chir
Walker, T. (2021, September 4). Yes, we can do it! Energy transition in Baden- Württemberg [Doch, wir schaffen das! Energiewende in Baden-Württemberg]. DIE	ZEIT.	https://www.zeit.de/2021/36/energiewende- baden- wuerttemberg- gruene- klimapolitik- thekla- walker/komplettansicht
Wurster, S. (2017). Energy transition in Baden-Württemberg: Scope and consequences [Energiewende in Baden-Württemberg: Ausmaß und Folgen]. In F. Hörisch & S. Wurster (Eds.), The green-red experiment in Baden-Württemberg [Das grün-rote Experiment in Baden-Württemberg] (pp. 251–278). Springer Fachmedien Wiesbaden. https://doi.org/10.1007/978- 3- 658- 14868- 3_10
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CHAPTER 6	
Spain
Abstract This chapter examines climate policy efforts across six Spanish Autonomous Communities that joined the Under2 Coalition at different timepoints: founding member Catalonia, early joiners Basque Country and Foral Community of Navarre, and later joiners Andalusia, Community of Madrid, and Galicia. Operating within Spain’s multilevel governance system, these regions filled a policy vacuum created by limited national climate action at the national level prior to 2021. Catalonia demonstrates the clearest leadership profile, combining cognitive, entrepreneurial, and exemplary dimensions through pioneering legislation and transnational diplomacy. The Basque Country exhibits strong entrepreneurial orientation through sustained policy-based climate action, while Navarre shows entrepreneurial impulses undermined by implementation deficits. Among later joiners, Andalusia displays cognitive leadership rooted in two decades of strategic planning, Madrid remains comparatively incremental in its approach to climate policy despite economic capacity, and Galicia demonstrates increasing dynamism following strategically timed Under2 Coalition accession during COP 26. The analysis reveals that Under2 Coalition membership reinforced pre-existing leadership among founding and early members through reputational incentives, while its influence on later joiners appears to serve primarily to formalize existing commitments rather than catalyze transformation toward carbon neutrality.

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© The Author(s) 2026
J. Tosun et al., Subnational Climate Leadership Dynamics Among Under2 Coalition Members, Palgrave Studies in Sub-National
Governance, https://doi.org/10.1007/978-3-032-12610-8_6
Keywords Climate leadership • Reputational incentives • Spanish multilevel governance • Subnational climate diplomacy • Territorial politics
Introduction
Climate policy in Spain operates across multiple levels of government, with responsibilities in areas such as transport, industry, agriculture, and the environment shared between the central administration and the regional governments, also known as Autonomous Communities (Vargas- Amelin & Pindado, 2014). This multilevel structure has proven particularly significant in shaping the country’s climate response.
Spain’s approach to climate policy has evolved from passivity to an active, albeit lagging, stance (Costa, 2011). Until the mid-2010s, it often followed the EU’s ambitious policy guidelines without pursuing more ambitious national-level climate policy (Solorio, 2016). However, beginning in 2018, the country strengthened its commitment by adopting a number of climate policies. The most notable of these was its first national Framework Law on Climate Change and Energy Transition, ratified in 2021 (Law 7/2021) (Rodrigo et al., 2023).
This delayed national response to climate change created a policy vacuum that some regions moved quickly to fill. In the absence of a general framework prior to 2021, several regions used their decentralized competences to pursue more ambitious climate action than the central administration (Cocciolo, 2020). Most notably, Catalonia adopted Law 16/2017 on climate change, Andalusia enacted Law 8/2018 on measures against climate change and for the transition to a new energy model, and the Balearic Islands passed Law 10/2019 on climate change and energy transition (Camargo et al., 2020).
These climate policy acitivities at the subnational level are also reflected in the participation of Spanish regions in U2C. Catalonia became a founding member in May 2015, followed by the Basque Country and the Foral Community of Navarre as early participants later that year. Andalusia, the Community of Madrid, and Galicia joined subsequently between 2016 and 2021.
Existing literature suggests that subnational climate policy in Spain is often driven by territorial motives, such as bolstering international visibility as “nation-states-in-waiting” (Cornago, 2010)—regions with strong national identities seeking greater autonomy—which extend beyond climate-related objectives in the narrow sense (Conversi & Friis Hau, 2021). This chapter addresses a key gap in understanding: whether and how U2C membership has enhanced regional climate policy effort in Spain, with particular attention to how the timing of joining (founding, early, or late) has influenced both initial commitments and long-term policy development.
Founding Member
Catalonia
Catalonia is Spain’s second-largest regional economy, characterized by a high degree of industrialization and a powerful service sector. The region faces distinctive climate vulnerabilities: its densely populated coastline is highly susceptible to sea-level rise and water scarcity, while its mountainous areas in the Pyrenees are experiencing the impacts of climate change on snow-dependent water resources and tourism.
These environmental pressures intersect with significant political capacity for action. Catalonia’s constitutional status as a “nationality”—a designation within the Spanish framework that grants extensive self-governing powers—has provided the region with substantial authority to adopt environmental and climate policies. This constitutional autonomy enabled Catalonia to take a pioneering role in pursuing policy-based climate action, exemplified by its adoption of Spain’s first framework law on climate change, enacted before the central state’s Law 7/2021 (Rodríguez Beas, 2019).
However, Catalonia’s approach to climate policy cannot be understood solely through a policy-specific lens. Recent research has linked the development of the climate policy agenda to the region’s demands for greater autonomy, revealing that climate policy serves dual purposes: addressing climate change while simultaneously asserting political distinctiveness vis- à- vis the central government (Enguer & Navarrete, 2025). This intersection of policy-based climate action and territorial politics shapes the complex—and at times contentious—relationship between Catalonia and the central government in Madrid.
Early Joiners
Basque Country
The Basque Country possesses a strong industrial base and ranks among Spain’s most economically developed regions, with an income level among the highest in the country. Located along the Cantabrian Sea, the region faces distinct climate vulnerabilities: coastal threats including sea-level rise and storm surges, as well as increasing urban temperatures inland.
Like Catalonia, the Basque Country holds constitutional recognition as a nationality with substantial autonomy, supported by a well-established regional government and institutional framework capable of designing and implementing climate policies. A pivotal shift in the region’s climate agenda occurred following the 2009 regional elections, when the Socialist Party formed a single-party government (De la Peña, 2013). This marked the first time in over a decade that climate policy was not relegated to junior coalition partners, enabling the development of the region’s first comprehensive sustainable development strategy and signaling a new prioritization of climate action.
As with Catalonia, the Basque Country’s climate policy profile reflects motivations that extend beyond climate concerns. The region’s international commitments to fighting climate change—including its early participation in U2C—have been shaped by domestic political dynamics and aspirations to project the region internationally through identity-driven climate diplomacy (Enguer, 2025). Climate action in the Basque Country thus has been both a strategy for adressing climate change and a vehicle for asserting regional distinctiveness on the international stage.
Foral Community of Navarre
The Foral Community of Navarre is a small but economically advanced region with a diversified industrial base. Key sectors include automotive and pharmaceutical manufacturing, as well as wind-turbine production— reflecting the region’s strength in producing renewable energy. Agriculture and hydroelectric and wind power generation remain important in rural areas. Geographically, Navarre spans a climatic gradient from wet Pyrenean mountains in the north to semi-arid Ebro river valleys in the south, creating divergent climate vulnerabilities: water scarcity and drought in the south, and flood risks in the north.
Navarre’s status as a “Foral Community”—a designation that grants it exceptional fiscal and political autonomy within the Spanish state—has been instrumental for its pioneering role in renewable energy development (López González et al., 2007). This autonomy has also allowed the region to pursue policy-based climate action independently, transitioning from fragmented initiatives toward a more structured governance framework beginning in 2010. However, unlike Catalonia and the Basque Country, Navarre’s climate policy profile has been marked by internal political challenges. Progress has at times been constrained by divergences in political will between the regional executive and legislature, as well as by implementation delays (Alenza, 2023), suggesting that institutional capacity alone does not guarantee consistent climate leadership.
Later Joiners
Andalusia
Andalusia is Spain’s most populous region, with an economy deeply tied to agriculture and tourism. Its climate ranges from Mediterranean to semi-arid, and the region regularly endures extreme heat waves and droughts. Geographically diverse—spanning the Sierra Nevada mountains, the Guadalquivir plain, and extensive Atlantic and Mediterranean coastlines—Andalusia faces acute vulnerabilities to water scarcity, desertification, and wildfires.
In recent years, the region’s energy mix has undergone rapid transformation, shifting from historical dependence on fossil fuels toward growing reliance on renewable energy. This transition represents both a response to climate risks and a strategy for economic modernization and diversification, capitalizing on Andalusia’s abundant solar resources to position itself as a leader in Spain’s energy transition (Román-Collado & Colinet Carmona, 2021). Significantly, Andalusia became the second Autonomous Community to adopt a framework law on climate change—following only Catalonia and preceding the central state’s Law 7/2021 by three years (De la Varga, 2022). This proactive stance suggests that the region’s climate policy ambition was driven as much by economic opportunity as by the need to respond to the materialzing impacts of climate change.
Community of Madrid
The Community of Madrid serves as Spain’s economic engine, with the highest economic activities in absolute terms. Unlike other regions presented here, Madrid’s climate challenges stem primarily from its intense urban and metropolitan character. The service-dominated economy makes energy consumption in buildings, transportation, and services the critical focus for climate change mitigation efforts. The region experiences a continentalized Mediterranean climate, and its high population density—concentrated in the capital and surrounding metropolitan area—creates a pronounced urban heat island effect and heightened vulnerability to heat waves.
The region’s wealth and substantial governance capacity enable major climate policy efforts, including building an extensive public transit network, providing EV incentives, and establishing low-emission zones. However, Madrid’s energy profile presents a significant obstacle to deeper decarbonization. Despite recent rapid expansion of solar photovoltaic capacity, the overall share of renewables in Madrid’s energy mix remains among the lowest in Spain, as the region grapples with exceptionally high baseline energy demand from transport and buildings (Alonso et al., 2016; Montoya et al., 2014). This gap between governance capacity and energy transition progress distinguishes Madrid from other regional leaders.
Galicia
Galicia’s economy, historically rooted in agriculture and fishing, is now supported by a diverse industrial base that includes textiles, automotive manufacturing, and a shipbuilding sector increasingly diversifying into offshore wind energy. The region’s Atlantic location creates significant climate vulnerabilities, particularly coastal flooding, erosion, and sea-level rise.
Galicia’s constitutional status as a nationality provides a favorable competency framework for adopting climate policies. This has facilitated a recent renewal of its climate change mitigation goals, marking a departure from an outdated policy framework exemplified by the still-active but obsolete Law 1/1995 on Environmental Protection (Calatayud, 2009). Unlike Madrid, Galicia benefits from an advantageous energy profile: most electricity generation already derives from renewable sources, notably wind and hydropower, placing it above the national average (Castro- Santos & Filgueira-Vizoso, 2023; Simón, 2012). This existing renewable
energy foundation provided Galicia with a stronger starting point for ambitious climate policy than many other Spanish regions.
Comparative Analysis
Policies
The Spanish subnational entities increasingly adopted climate policies following their incorporation into U2C (Fig. 6.1). This pattern is particularly pronounced among founding and early members. All climate change framework laws adopted by these regions—Catalonia, the Basque Country, and the Foral Community of Navarre—were enacted after 2015. The Basque Country stands out as the only region to have adopted two such laws, one in 2019 and another in 2024, suggesting sustained climate policy commitment.

Fig. 6.1 Adoption of climate policies

Regarding climate plans, the temporal pattern also points toward postmembership intensification, though with some nuance. While Catalonia adopted an equal number of plans before and after signing the U2C MoU (three in each period), both the Basque Country (four plans) and the Foral Community of Navarre (two plans) adopted all their plans after 2015. The single exception—Navarre’s Climate Change Strategy 2010–2020, enacted in 2011—holds limited significance for assessing policy ambition, as it was withdrawn just months after approval, reflecting political disagreement over the level of climate policy effort.
Among later joiners, the relationship between U2C membership and policy adoption is less straightforward. Only Andalusia adopted a climate change framework law, enacted two years after joining U2C. While each of the later joiners has adopted two climate-related plans since membership, the majority of their planning activity preceded their participation: Madrid adopted five plans before joining, Andalusia four, and Galicia three. This suggests that for later joiners, U2C membership may represent recognition of existing climate policy effort rather than a catalyst for new policy development.
Catalonia’s early commitment to climate policy was distinguished by cognitive leadership—deploying ideas and participatory processes to reframe climate action as a cross-sectoral priority. This approach was evident in the 2008 Framework Plan for Climate Change Mitigation, crafted through an extensive participatory process involving 800 individuals and 500 organizations. The plan helped embed a shared vision of climate action as a socioeconomic project rather than a narrow concern to mitigate climate change. Building on this foundation, the 2012–2020 Energy and Climate Change Plan exemplified further cognitive innovation by explicitly subordinating energy policy to climate objectives, marking a significant recalibration of policy priorities.
Parallel to this cognitive dimension, Catalonia displayed entrepreneurial qualities. From joining The Climate Group’s States & Regions network in the 2000s to co-founding U2C in May 2015, Catalonia actively brokered alliances and used diplomacy to amplify its influence beyond its territorial boundaries. Such moves demonstrate the region’s ability to draw attention to its climate policy agenda and build transregional coalitions.
Catalonia’s post-U2C co-founding policy record contains significant elements of exemplary leadership. The sequence of policy outputs— including Law 16/2017 on climate change, the 2019 declaration of a climate emergency, and Decree-Law 16/2019 introducing binding measures to promote renewable energy—shows a willingness to implement innovative measures that other subnational actors can observe and learn from (De la Varga, 2018). The 2023 Energy Outlook further consolidates this long-range vision, positioning Catalonia as a demonstrator of pathways to carbon neutrality by mid-century (Casanova et al., 2023).
Even before officially joining U2C in 2015, the Basque Country had exercised entrepreneurial leadership by strategically negotiating its entry into transnational networks such as ENCORE (1993), NRG4SD (2002), and Climate Group (2010). After 2015, U2C membership offered additional platforms for multilevel and multi-stakeholder dialogues, fostering consensus around ambitious climate action (Orkestra et al., 2021). This sustained participation in transnational networks can be regarded as exemplary leadership, positioning the region as a model of identity-driven environmental diplomacy (Kerr, 2024).
Alongside its transnational engagement, the Basque Country also demonstrated cognitive leadership through the development of influential strategic frameworks. Comprehensive, long-term strategies (KLIMA 2050, Euskadi 2030) and landmark legislation (the Law on Public Administration Energy Sustainability and the Law on Energy Transition and Climate Change) charted a credible path toward decarbonization. More than merely internal roadmaps, these documents articulate an integrated model of sustainable development capable of inspiring the agendas of other subnational governments.
The climate policy path of the Foral Community of Navarre demonstrates a distinct form of entrepreneurial leadership, characterized by diplomatic engagement to build momentum for climate action. This was most evident when the region endorsed the Paris Agreement and joined U2C in 2015, decisions that served to draw attention to its international commitments. This continued with the incorporation of the SDGs in 2016–2017 and the launch of a participatory process for its Climate Change Roadmap (HCCN-KLINa) in 2018, showcasing an effort to broker consensus and propose a structured path forward after earlier political setbacks.
Despite these advances, Navarre’s climate policy profile has been undermined by implementation deficits. Its 2019 climate emergency declaration proved largely symbolic and produced no major new measures, while the Foral Law 4/2022 on Climate Change and Energy Transition deferred most binding actions by two to eight years and failed to meet first-year targets (Alenza, 2023). Consequently, the region’s accession to U2C in 2015 and SDG adoption (2016–2017) appear largely reactive—reflecting alignment with global norms rather than proactive leadership. Navarre thus exemplifies the limits of entrepreneurial diplomacy when divorced from structural implementation capacity.
Andalusia’s climate policy progression reflects a strong cognitive leadership profile, built on two decades of strategic planning and technical consolidation. Beginning with the Andalusian Strategy for Climate Change (2002), followed by the Climate Action Plan (2007) and the parallel Energy Sustainability Plan, and continuing through later iterations such as the Energy Strategy 2020 and Energy Strategy 2030, the region has consistently produced sector-spanning frameworks. These policy outputs demonstrate sustained capacity to generate evidence-based roadmaps shaping decisions across land use, transport, waste, agriculture, industry, and the energy system.
This cognitive core has been complemented by entrepreneurial outreach. Andalusia’s accession to U2C in September 2016 and its alignment with EU and Paris-consistent approaches to policy-based climate action highlight outward-facing diplomacy designed to stimulate policy learning and lend legitimacy to domestic measures. There are also elements of exemplary leadership—most notably the region’s legislative framework (Law 8/2018) and the 2021–2030 Andalusian Climate Action Plan—which position Andalusia as a potential demonstrator of integrated mitigation and energy transition pathways.
The Community of Madrid’s climate policy profile is defined less by transformative shifts than by a persistent, energy-centered approach built through successive, technically detailed plans. Beginning with the Energy Plan 2004–2012 and continuing through the Energy Plan 2016–2020 and targeted measures such as the Energy Saving and Efficiency Plan for Public Buildings (2017, updated 2022), the region consistently emphasized energy diversification, efficiency, and renewables. Parallel road- maps—the Blue Plan+ (2013–2020) and its 2016 review, the Decarbonization and Environmental Protection Plan 2021–2024, and the integrated Energy, Climate and Air Strategy 2023–2030—illustrate an incremental layering of measures across air quality, transport, buildings, industry, and natural systems.
This trajectory reflects primarily structural leadership: Madrid’s strength lies in its capacity for technical planning and policy design, generating credible roadmaps and public sector measures that structure regional decision- making. However, Madrid lacks the exemplary dimension seen in earlier-joining regions, with its policy approach remaining largely technocratic rather than pioneering.
Galicia’s climate policy profile demonstrates pronounced cognitive leadership that has been progressively reinforced by entrepreneurial and structural approaches since 2018. The region’s foundational Galician Energy Guidelines 2018–2020 established early cognitive reframing by linking renewable energy development to job creation, positioning decarbonization as a socioeconomic opportunity. This cognitive foundation expanded with the Galician Climate Change and Energy Strategy 2050 (2019), which embedded climate action within broader regional development goals (Pérez et al., 2022).
By strategically timing its U2C accession during COP26, Galicia exhibited entrepreneurial skill, leveraging global visibility to accelerate domestic reform. Concurrently, the implementation of binding measures through the Integrated Regional Plans (2019–2023 and 2030) reflects growing structural leadership. What most clearly distinguishes Galicia is the mutually reinforcing dynamic between its cognitive reframing and entrepreneurial networking—a combination that has enabled the region to transition from policy planning to meaningful implementation.
Policy Instruments
Spain’s U2C members implemented a diverse set of climate policy instruments through various laws and plans over the past decade (Fig. 6.2). However, unlike the clear temporal pattern observed in policy adoption dates, the distinction between founding, early, and late U2C members is less clear when examining the variety and timing of policy instruments.
The regions deploying the most varied policy instruments are the Foral Community of Navarre (8 types), the Community of Madrid (7), and Catalonia (6). Notably, the founding and early members among these began implementing measures considerably earlier than Madrid. While Madrid only initiated its portfolio of instruments in 2023, Catalonia introduced its first climate tax in 2010, followed by public procurement, standards, bans, and information and training measures in 2017. That same

Fig. 6.2 Policy instruments to reduce regional GHG emissions year, Navarre also adopted taxes, public procurement, and standards, demonstrating early experimentation with binding measures.
A second tier comprises two later joiners—Andalusia and Galicia— alongside one early member, the Basque Country. Interestingly, the Basque Country has been the least active, deploying only three instrument types despite its early U2C membership. Equally notable is that Andalusia was the earliest of all six regions to implement climate policy instruments, introducing standards, certifications and labels, and information and training as far back as 2007—eight years before joining U2C and nine years before Catalonia adopted its framework law.
The temporal relationship between U2C membership and instrument adoption differs markedly between cohorts. With few exceptions—such as a voluntary agreement in the Basque Country and a tax in Catalonia—founding and early members adopted most of their instruments after joining U2C, suggesting the coalition may have catalyzed diversification of their policy toolkits. The opposite pattern characterizes later joiners: both Andalusia and Galicia already had multiple policy instruments in place before accession, while Madrid compressed its entire instrument portfolio into a single year (2023) after joining. This suggests that for later members, U2C accession may represent formalization or international recognition of existing domestic efforts rather than a stimulus for new action.
Catalonia emerged as an early adopter of fiscal instruments, introducing climate taxes as early as 2010. Following its U2C co-founding in 2015, the region significantly expanded its policy toolkit from 2016 onward, incorporating a broader suite of regulatory and support measures including standards, public procurement, bans, and training programs. This diversification suggests that U2C membership may have encouraged experimentation beyond the fiscal measures Catalonia had already pioneered.
Similarly, the Basque Country’s initial approach centered on voluntary agreements (circa 2010–2012), but its U2C membership coincided with a gradual shift toward fiscal and regulatory instruments around 2020–2022. The Foral Community of Navarre, having joined the coalition in 2015, began consistently deploying a comprehensive mix of economic, regulatory, and voluntary instruments from the late 2010s onward. For both regions, the timing suggests U2C participation may have reinforced a transition toward more binding policy approaches.
Andalusia’s strategy began with “soft” instruments such as standards, certifications, and training initiatives (circa 2007–2010), predating its climate framework law and U2C membership by nearly a decade. After joining U2C in 2016, it incorporated additional instruments including public procurement and voluntary agreements in the mid-to-late 2010s, though the incremental nature of this expansion suggests continuity rather than transformation.
The Community of Madrid demonstrates a markedly different pattern. Despite joining U2C in 2019, concentrated deployment of multiple instruments occurred only much later, peaking in the 2022–2024 period with a sudden proliferation of subsidies, public procurement, standards, bans, certifications and labels, voluntary agreements, and training programs. This delayed, compressed adoption suggests factors other than U2C membership—perhaps political shifts or EU-level pressures—drove Madrid’s policy intensification.
Galicia’s trajectory shows a later but concentrated adoption of instruments, mostly around 2019–2021, a period that directly overlaps with and immediately follows its U2C accession in 2021. This temporal alignment is among the strongest observed across Spanish regions, suggesting that for Galicia, coalition membership may have served as a catalyst for rapid policy instrument diversification.
Targets
The Spanish regions examined in this study established GHG emissions reduction targets across different timeframes through a combination of policy plans and laws, implemented both before and after their U2C accession (Fig. 6.3). Comparative assessment demonstrates that founding and early U2C members implemented a greater total number of GHG emissions reduction targets compared to later joiners. While the number of medium-term targets is identical across cohorts, differences in short- and long-term targets clearly distinguish the founding and early members as more ambitious.
Specifically, Catalonia, the Basque Country, and the Foral Community of Navarre have each adopted two short-term emissions targets, matching

Fig. 6.3 Greenhouse gas emissions reduction targets
Andalusia (two targets) and surpassing Galicia (one target) and the Community of Madrid (which has yet to adopt any short-term target). All six regionsadopted two medium-term targets, indicating parity on this dimension. However, the contrast becomes most pronounced in longterm targets: all founding and early members adopted two distinct longterm GHG emissions reduction targets, while among later joiners, only Galicia matches this level of ambition. Andalusia adopted one long-term target, while Madrid adopted none.
The temporal relationship between U2C membership and target adoption reveals divergent patterns across cohorts. Notably, Andalusia set the earliest short- and medium-term targets in the dataset, dating back to 2007—nine years before joining U2C—highlighting its pioneering role in GHG emissions reduction planning despite its late accession to the coalition. Similarly, Catalonia established its initial short- and medium-term targets before U2C was created in 2015. However, all subsequent GHG emissions reduction targets adopted by Catalonia and the other founding and early members came after their entry into U2C, suggesting the coalition may have reinforced target-setting ambition and encouraged adoption of long-term horizons.
Later joiners display a more varied pattern that suggests U2C membership played a less catalytic role. Andalusia adopted three targets before joining and only one afterward, indicating continuity with its pre-existing policy profile. The Community of Madrid adopted one target before and one after membership, showing minimal intensification. Only Galicia presents a pattern consistent with U2C influence, having adopted one target prior to joining and two afterward—both of them long-term targets that align with the coalition’s emphasis on mid-century decarbonization pathways. This suggests that for most later joiners, U2C accession formalized rather than transformed existing target-setting practices.
Catalonia first set a 2050 net-zero GHG emissions target in Law 16/2017, though this was later annulled by constitutional challenges from the central government. Despite this setback, its early U2C engagement (2015) appears to have supported renewed ambition over time, leading to the adoption of a 29% GHG reduction target for 2030 in 2025. This trajectory illustrates both the constraints of multilevel governance conflicts and the resilience of subnational climate ambition.
The Basque Country’s GHG trajectory evolved substantially over time, shifting from a 14% emissions cap above 1990 levels (2008–2012) to legally binding net-zero GHG emissions by 2050. Interim targets also tightened, progressing from a 40% reduction by 2030 (2015) to 45% by 2030 in subsequent legislation. This escalating ambition coincides with the region’s U2C membership and sustained participation in transnational climate networks.
The Foral Community of Navarre’s GHG emissions reduction framework surged from a 45% reduction target by 2030 (2017) to 55% by 2030, with carbon neutrality advanced to 2040. This represents one of the most ambitious target-setting trajectories among Spanish regions, though as noted earlier, implementation challenges have undermined the credibility of these commitments.
Among later joiners, Andalusia’s GHG emissions reduction target jumped dramatically from 18% by 2030 (2018) to 55% by 2030 (2022), aligning the region with the requirements stipulated by EU law following its U2C accession. The Community of Madrid’s targets remained notably more incremental—rising from only 20% reduction by 2020 to 23% by 2030—reflecting the region’s comparatively modest climate ambition despite its economic capacity and late U2C membership.
Galicia’s GHG emissions reduction ambition increased most significantly of all regions examined, escalating from a 24.6% reduction by 2030 (2019) to 75% by 2030 (2025). Its carbon neutrality target advanced from 2050 (2022) to 2040 (2025), making it among the most ambitious Spanish regions. This occurred during and immediately after its U2C accession in 2021, suggesting the coalition may have provided both legitimacy and impetus for strengthening the regional government’s commitment to climate action.
Leadership
The six Spanish Autonomous Communities that are U2C members present a remarkably uneven but analytically coherent map of subnational climate leadership. Catalonia represents the clearest and most sustained leadership profile. Its cognitive leadership has been evident since the late 2000s, when climate policy was reframed as a cross-sectoral socioeconomic project. This image of climate policy was steadily reinforced by entrepreneurial diplomacy—joining international networks, co-founding U2C, and actively extending its influence beyond regional borders. Exemplary leadership emerged through pioneering policies such as Law 16/2017, which initially set a net-zero target for GHG emissions to be reached by 2050. Though this law was annulled by constitutional challenge, Catalonia’s ambition persisted, leading to a 29% reduction target for 2030 (2025), demonstrating sustained commitment shaped by its early U2C engagement.
The Basque Country also demonstrates multidimensional leadership, though with a somewhat different balance. Its strong entrepreneurial orientation was expressed through decades of active participation in transnational networks, long before its entry into U2C as an early member in 2015. This external engagement was matched internally by cognitive leadership, visible in long-range strategies like KLIMA 2050, which combined decarbonization with a wider sustainable development model. The evolution of its GHG emissions reduction targets—moving from an early emissions cap above 1990 levels to a legally binding net-zero target, with interim 2030 targets tightening from 40% to 45% GHG emissions reduc- tions—further reflects its leadership aspirations in ambitious target- setting. Additionally, the Basque Country’s transition from voluntary agreements to regulatory and fiscal tools demonstrates exemplary leadership in the development of climate policy instruments.
The Foral Community of Navarre presents a less consistent profile. Its entrepreneurial impulses have been clear in symbolic acts such as endorsing the Paris Agreement, joining U2C in 2015, and launching participatory processes to craft strategic roadmaps. This diplomatic activism is reflected in a significant surge in GHG emissions reduction ambition, from a 45% reduction by 2030 (2017) to 55% (2022) and carbon neutrality by 2040. Yet Navarre’s record of climate policy implementation has been uneven, with delayed or under-delivered commitments undermining the credibility of these targets. While Navarre has experimented broadly with policy instruments—deploying the most diverse toolkit among all Spanish regions examined—deficits in follow-through suggest that its leadership often leaned toward reactive alignment with global norms rather than proactive innovation.
Andalusia reflects a distinctive cognitive leadership, rooted in two decades of comprehensive planning that consistently integrated climate concerns across economic sectors. It set the earliest short- and mediumterm GHG emissions reduction targets in the group, dating back to 2007—nine years before joining U2C. Its strategies and action plans reveal sustained capacity to generate technical knowledge and policy frameworks, culminating in a notable jump in its GHG target from 18% (2018) to 55% by 2030 (2022). Complementary entrepreneurial leadership traits are visible in its engagement with U2C in 2016 and alignment with EU requirements, while exemplary leadership emerges in legislative milestones such as Law 8/2018. For Andalusia, U2C membership appears to have formalized and amplified pre-existing climate commitments rather than catalyzed new directions.
The Community of Madrid has primarily relied on structural leadership, expressed through administrative capacity to develop successive energy-focused plans and roadmaps. These have been characterized by technical expertise but have generally lacked ambitious reframing or outward- facing entrepreneurship, as reflected in Madrid’s incremental GHG emissions reduction targets—rising from only 20% by 2020 to 23% by 2030. Madrid’s climate policy profile has remained comparatively modest in scope and ambition, suggesting that being a country’s capital region and possessing economic and administrative capacity alone does not translate into strong climate policy leadership.
Galicia, by contrast, has shown increasingly dynamic climate policy development since 2018. Cognitive reframing positioned decarbonization as an engine of socioeconomic development, while entrepreneurial leadership was displayed in its strategically timed U2C accession during COP26. The region’s leadership has grown through the adoption of binding plans and a dramatic increase in its ambition for reducing GHG emissions, from a 24.6% reduction by 2030 (2019) to 75% (2025), while committing itself to achieving carbon neutrality in 2040 instead of 2050. Galicia’s trajectory suggests that late entry into transnational coalitions such as U2C need not preclude strong leadership, provided sufficient capacity, favorable energy profiles, and strategic political timing align.
Conclusion
Spain’s climate policy at the national level has evolved from merely implementing EU requirements to actively developing its own approach (Costa, 2011; Solorio, 2016). This policy shift at the central level—most visibly embodied in the adoption of Law 7/2021—occurred rather late and now interacts with a situation in which Spanish regions have developed their own climate policy approaches, largely in response to the absence of ambitious national climate policy.
Against this backdrop, we examined the various forms of leadership displayed by one Spanish founding member of U2C (Catalonia), two early members (the Basque Country and the Foral Community of Navarre), and three regions that joined later (the Community of Madrid, Andalusia, and Galicia). We traced the evolution of policy-based climate action in these territories both before and after joining the coalition. In doing so, we assessed the book’s two central propositions (see Chap. 2): that founding and early members of transnational organizations such as U2C face the strongest reputational incentives, which induce them to demonstrate elevate levels of climate policy activity and create long-term pressures to sustain and enhance those commitments.
U2C membership has indeed often reinforced pre-existing leadership among Spain’s founding and early member regions. Catalonia exemplifies this pattern, leveraging its founding status to amplify cognitive and entrepreneurial leadership, subsequently adopting pioneering policies that served an exemplary function for other Spanish regions. Similarly, the Basque Country used its early U2C membership to pursue identity-driven climate policy efforts. Even the Foral Community of Navarre, despite significant policy implementation deficits, utilized its 2015 U2C accession to generate entrepreneurial momentum, aligning itself with global norms and substantially increasing its stated GHG emissions reduction ambi- tions—though credibility gaps remained.
In contrast, the climate policy profiles of U2C later joiners are more varied. Andalusia had established strong cognitive leadership through strategic planning years before joining U2C in 2016, with climate targets dating back to 2007. U2C membership served primarily to complement and lend external legitimacy to its region-specific approach to climate action rather than to develop new directions for climate policy. The Community of Madrid’s late accession and its subsequent concentrated adoption of policy instruments in 2023 reflect modest ambition despite the region’s high-profile status as the country’s capital and its economic and administrative capacity. Galicia, meanwhile, presents a more complex case: by coupling strategically timed accession at COP26 with growing cognitive capacity and favorable renewable energy endowments, it converted late entry into elevated climate policy ambition.
In summary, U2C founding and early members have consistently demonstrated higher climate policy effort in both the short and long term. However, this relationship is conditional on favorable regional conditions such as the capacity to produce renewable energy. Policy implementation shortfalls as in Navarre demonstrate that reputational incentives do not automatically translate into policy delivery, while the offsetting effects of institutional capacity, favorable energy profiles, and strategic timing (as in Galicia) show that later joiners can achieve high ambition.
References
Alenza, J. F. (2023). Navarra (2022): El despertar indolente de la legislación climática de Navarra [Nvarre (2022): The slow awakening of climate legislation in Navarre]. Anuario de Derecho Ambiental. Observatorio de Políticas Ambientales, 1, 1025–1054.
Alonso, P. M., Hewitt, R., Pacheco, J. D., Bermejo, L. R., Jiménez, V. H., Guillén, J. V., Bressers, H., & De Boer, C. (2016). Losing the roadmap: Renewable energy paralysis in Spain and its implications for the EU low carbon economy. Renewable Energy, 89,	680–694.	https://doi.org/10.1016/j. renene.2015.12.004
Calatayud, A. (2009). Localización: Análisis y reflexiones sobre el Derecho Ambiental en	Galicia.	20–25. https://derechopublicoglobal.es/wp- content/ uploads/2013/10/Analisis_y_Reflexiones_sobre_el_Derecho_Ambiental_en_ Galicia.pdf
Camargo, J., Barcena, I., Soares, P. M., Schmidt, L., & Andaluz, J. (2020). Mind the climate policy gaps: Climate change public policy and reality in Portugal, Spain and Morocco. Climatic Change, 161(1), 151–169. https://doi. org/10.1007/s10584- 019- 02646- 9
Casanova, A., Esteve, J., & Margarit, J. (2023). Energy outlook of Catalonia by 2050 (PROENCAT50). Institut Català d’Energia (ICAEN). https://icaen. gencat.cat/web/.content/10_ICAEN/17_publicacions_informes/ PROENCAT/20230512_Proencat- 2050_web_Acc.pdf
Castro-Santos, L., & Filgueira-Vizoso, A. (2023). The decarbonisation of Galicia using renewable marine energy. RE&PQJ, 19(1). https://doi.org/10.24084/ repqj19.231
Cocciolo, E. (2020). Cambio climático en tiempos de emergencia. Las comuni- dades autónomas en las veredas del “federalismo climático” español. Revista Catalana de Dret Ambiental, 11(1). https://doi.org/10.17345/rcda2868
Conversi, D., & Friis Hau, M. (2021). Green nationalism. Climate action and environmentalism in left nationalist parties. Environmental Politics, 30(7), 1089–1110. https://doi.org/10.1080/09644016.2021.1907096
Cornago, N. (2010). On the normalization of sub-state diplomacy. The Hague Journal of Diplomacy, 5(1–2),	11–36. https://doi.org/10.116 3/1871191x- 05010102
Costa, O. (2011). Spanish, EU and international climate change policies: Download, catch up, and curb down. In R. K. W. Wurzel & J. Connelly (Eds.), The European Union as a leader in international climate change politics (pp. 179–194). Routledge.
De la Peña, A. (2013). Políticas de mitigación del cambio climático en la Comunidad Autónoma del País Vasco. Un análisis comparado con Escocia, Cataluña y Flandes. XI Congreso de la AECPA, Sevilla. https://www.recp.es/files/view/ docx/congress- papers/11- 0/835/
De la Varga, A. (2018). Estudio de la ley catalana 16/2017, de 1 de agosto, de cambio climático, y análisis comparativo con otras iniciativas legislativas subestatales. Revista Catalana de Dret Ambiental, 9(2). https://raco.cat/index. php/rcda/article/view/348629
De la Varga, A. (2022). Las medidas autonómicas para mitigar y adaptar el cambio climático. Análisis comparativo de las leyes autonómicas de Catalunya, Andalusía e Illes Balears. Anuario de La Facultad de Derecho de La Universidad Autónoma de Madrid, 26, 251–268.
Enguer, J. (2025). Comparing regional and national climate policy preferences: An analysis of political parties in the Basque country and Catalonia. Publius: The Journal of Federalism, 55(1), 30–57. https://doi.org/10.1093/pub- lius/pjae035
Enguer, J., & Navarrete, R. M. (2025). Protecting the climate to challenge the centre? Secessionism and climate policy preferences in Catalonia. Regional & Federal Studies, 35(2), 205–228.	https://doi.org/10.1080/1359756 6.2023.2263834
Kerr, S. (2024). Greening self-government? Incorporation of environmental justifications into sub-state nationalist claim making in Spain. Ethnicities, 24(5), 659–680. https://doi.org/10.1177/14687968231171168
López González, L. M., Sala Lizarraga, J. M., Míguez Tabarés, J. L., & López Ochoa, L. M. (2007). Contribution of renewable energy sources to electricity production in the autonomous community of Navarre (Spain): A review. Renewable and Sustainable Energy Reviews, 11(8), 1776–1793. https://doi. org/10.1016/j.rser.2006.01.002
Montoya, F. G., Aguilera, M. J., & Manzano-Agugliaro, F. (2014). Renewable energy production in Spain: A review. Renewable and Sustainable Energy Reviews, 33, 509–531. https://doi.org/10.1016/j.rser.2014.01.091
Orkestra, Fernández Gómez, J., & Larrea Basterra, M. (2021). Fostering green financing at the subnational level. The case of the Basque Country. Ekonomiaz. Revista Vasca de Economía,	99(1),	150–181. https://doi. org/10.69810/ekz.1391
Pérez, S., Piñeiro, I., & Macho, M. (2022). Estrategia Gallega de Cambio Climático y Energía 2050. 733–741. https://aeclim.org/wp- content/ uploads/2023/01/RETOS_CAMBIO_CLIMATICO_PerezCastellanos_ 733- 741.pdf
Rodrigo, S. G., Alda-Fernandez, M., & Kölling, M. (2023). Climate governance and federalism in Spain. In A. Fenna, S. Jodoin, & J. Setzer (Eds.), Climate governance and federalism (1st ed., pp. 263–284). Cambridge University Press. https://doi.org/10.1017/9781009249676.014
Rodríguez Beas, M. (2019). El conflicto competencial sobre cambio climático entre España y Cataluña: Avances y retrocesos a la luz de la reciente Sentencia del Tribunal constitucional 87/2019, de 20 de junio, sobre la Ley 16/2017, de 1 de agosto, de cambio climático. A&C – Revista de Direito Administrativo & Constitucional, 19(77), 59. https://doi.org/10.21056/aec.v19i77.1212
Román-Collado, R., & Colinet Carmona, M. J. (2021). Energy efficiency’s key role in explaining the performance of energy consumption in Andalusia (Spain). Environmental Science and Pollution Research, 28(16), 20188–20208. https:// doi.org/10.1007/s11356- 020- 11829- 2
Simón, X. (2012). Eolic energy and rural development: An analysis for Galicia. Spanish Journal of Rural Development,	13–28. https://doi.org/ 10.5261/2012.GEN3.02
Solorio, I. (2016). Spanish climate change policy in a changing landscape. In R. K. W. Wurzel, J. Connelly, & D. Liefferink (Eds.), The European Union in international climate change politics (1st ed., pp. 183–196). Routledge.
Vargas-Amelin, E., & Pindado, P. (2014). The challenge of climate change in Spain: Water resources, agriculture and land. Journal of Hydrology, 518, 243–249. https://doi.org/10.1016/j.jhydrol.2013.11.035
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CHAPTER 7	
United Kingdom
Abstract This chapter examines climate policy efforts across four UK jurisdictions that joined the Under2 Coalition at different timepoints: founding member Wales, early joiner Scotland, and later joiners Northern Ireland and Isle of Man. Operating within the UK’s constitutionally asymmetric devolution framework, these subnational entities demonstrate varied climate leadership trajectories shaped by differential legislative powers, political contexts, and institutional capacities. Wales exhibits normative and cognitive leadership through pioneering an innovative intergenera- tional approach to climate action despite constitutional entanglement with English law limiting implementation capacity. Scotland, though only an early Under2 Coalition joiner, demonstrates the strongest climate ambition of all nations, driven by independence aspirations and serving as European Under2 Coalition co-chair, though recent difficulties in meeting the GHG emissions reduction target prompted the adoption of carbon budgets. Northern Ireland’s delayed policy-based climate action reflects post-conflict recovery priorities and repeated Assembly suspensions, while Isle of Man exemplifies followership through policy emulation and reliance on external expertise. The findings reveal mixed support for our two propositions regarding founding member advantages, highlighting how constitutional autonomy and political stability prove more decisive than membership timing in determining climate policy profiles.

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© The Author(s) 2026
J. Tosun et al., Subnational Climate Leadership Dynamics Among Under2 Coalition Members, Palgrave Studies in Sub-National Governance, https://doi.org/10.1007/978-3-032-12610-8_7
Keywords Climate Change Act • Climate followership • Climate leadership • Constitutional asymmetry • Devolved climate governance
Introduction
The UK has been described as a “paradoxical climate leader” (Rayner & Jordan, 2010). Despite being the first nation to enshrine carbon emissions reduction in law through the Climate Change Act 2008, climate policy development has since oscillated between the Conservative derogation of “green crap” and championing of net-zero delivery (Carter & Pearson, 2024). In short, a fundamental tension underlies the country’s enhanced climate ambitions and its record of inadequate policy delivery.
While valuable, this national-level focus has left subnational UK climate leadership in the shadows. When research does address it, subnational government is often presented as a singular, monolithic entity. This overlooks substantive “constitutional asymmetry”: the varied distribution of legislative and executive powers shaping subnational climate action (Royles & McEwen, 2015). In fact, UK subnational climate action is distinct from that of other political systems due to long-standing “Westminster pathologies”: short-termism, reactivity, fragmentation, siloed working practices, incrementalism, and top-down policymaking (Diamond et al., 2024).
Against this backdrop, this chapter explicates how four actors—three UK subnational devolved administrations and one British Crown Dependency—have developed their “climate actorness” in distinct ways, exemplified by their varied engagement with U2C. It probes Liefferink and Wurzel’s (2017; see also Chap. 2) four ideal types of subnational climate leadership—structural, entrepreneurial, cognitive, and exemplary— alongside followership (emulating the activities of leaders) to examine the extent to which a U2C co-founder (Wales) adopted more ambitious climate measures than early (Scotland) and later joining (Northern Ireland, Isle of Man) subnational counterparts.

For a valuable account of the different types of climate leadership exhibited by the UK in seeking to develop its own distinct “climate actorness”, see Moulton (2020).

Founding Member
Wales
Since 1998, Wales has been “entrained” in political devolution, receiving the most limited settlement of any UK devolved administration. This arrangement provided only secondary legislative powers, constrained financial autonomy, and continued reliance on Westminster, thereby restricting independent policymaking. In fact, of all the UK’s devolved administrations, Wales is the most intertwined with English Law (Cowell, 2017, p. 1248).
Nonetheless, Welsh climate ambition often exceeds that of the UK Government and other subnational actors (Royles & McEwen, 2015). In particular, Wales has leveraged subnational law to challenge economic primacy in favor of intergenerational thinking (Wallace, 2019). As Burns et al. (2018, pp. 7–8) put it, Wales has “re-fashioned environmental governance” by developing “distinctive institutions” and passing “innovative environmental legislation”—including the Wellbeing of Future Generations (Wales) Act 2015 and the Future Generations Commissioner for Wales. These (legislative) developments have been attributed to entrepreneurial subnational climate policy actors effectively negotiating contextspecific policy innovation (Messham & Sheard, 2020).
The existing literature also attributes Welsh climate activity to factors including: (1) the historic prioritization of environmental issues, including an early statutory duty to promote “sustainable development” across all subnational functions (Williams, 2006); (2) significant renewable energy (hydropower) capacity; (3) a desire to (re-)assert a distinctive subnational identity; (4) sustained political will for climate action, evident from sustained cross-party consensus across the Welsh Assembly; and (5) a stable governance framework which has enabled coherent, long-term climate policy development (Newman et al., 2024).
Furthermore, U2C membership provides opportunities to share solu- tions—including diverting 98 percent of municipal waste away from landfill in the two decades preceding 2022—and learn from others (e.g., on delivering a just industrial transformation; Irranca-Davies, 2024).
Early Joiner
Scotland
Scotland has implemented some of the most ambitious climate policies in the world. This activity has been attributed to contextual factors including substantive fiscal and renewable energy capacities and independence aspirations (McEwen & Bomberg, 2014).
Scottish decarbonization is inextricably linked to tensions between “old” (carbon-intensive) and “new” (renewable) energy sources. Advocacy for enhanced renewable energy capacity (from offshore wind to green hydrogen) juxtaposes Scotland’s reliance on substantive (and lucrative) North Sea oil and gas reserves.
Saliently, Scotland has prioritized a just net-zero transition, championed by ex-First Minister Nicola Sturgeon (Santos Ayllón & Jenkins, 2023). This echoes the deleterious legacy of 1980s coal mine closures—an archetypal unjust transition (Toulmin, 2025).
Others have likened Scottish climate ambition to Green Nationalism: a political ideology combining nationalist principles with climate action to consolidate claims to territorial distinctiveness and self-governance by adopting climate targets which exceed (inter)national ambitions. McEwen and Bomberg (2014) capture the situation well, describing how “the election of an autonomist, pro-independence party to the Scottish Government was associated with a step-change in the scale of ambition in the emissions reduction and renewable energy programmes. For parties seeking greater political autonomy or independent statehood, like the Scottish National Party […] climate ambition provides an opportunity to nurture perceptions of national prosperity and self-sufficiency, and to engage in ‘paradiplomacy’ to assert national autonomy and nurture their perception internationally as ‘nation-states in waiting’” (2014, p. 81). Similarly, Nash suggests Scottish climate policy echoes a logic of “anything Westminster can do [Holyrood] can do better” (Nash, 2021).
Ultimately, Scotland has diverged from, and regularly exceeded, UK climate policy ambitions. Despite (only) resembling an early joiner (having joined U2C in July 2015, two months after the founding signatories), Scotland is an important coalition member, serving as European co-chair. While climate action has seemingly been shuffled down the list of priorities following Sturgeon’s resignation, U2C offers a vehicle through which Scotland may maintain or step up its climate leadership.
Later Joiners
Northern Ireland
Northern Ireland has been described as displaying a “deficit in leadership” on climate policy vis-à-vis other UK subnational counterparts (Brennan et al., 2017, p. 3) and only joined U2C in 2021.
This deficit has been attributed to the Troubles and Northern Ireland’s ensuing reputation as a “post-conflict society” (Barry, 2009, p. 46) that prioritizes national security and economic recovery over climate action.
This status even led to Northern Ireland being dubbed the “dirty corner” of the (former) “Dirty Man of Europe” due to its lack of environmental and climate governance architectures (Brennan et al., 2017). Hwang describes relevant governance reforms as “piecemeal, ineffective, and sometimes retrogressive” and as precipitating environmental crises (2024, p. 30).
These interlocking governance challenges have been exacerbated by repeated suspension of the Northern Ireland Assembly. There have been significant periods—roughly one-third of its lifespan since 1998—when climate policy has been delivered without Assembly oversight.
Nonetheless, the opportunity still exists to intertwine climate action with (post-conflict) economic growth (Barry, 2009, p. 46), while U2C membership could help fill a growing “capability/expectation gap” in climate governance (Gravey et al., 2025).
Isle of Man
The Isle of Man has been “late to respond” to climate change, echoing an island saying of “Traa dy Liooar” (literally, “time enough”), whereby decisions are slow to be implemented (McCartney, 2023, p. 1134). The island only joined U2C in 2021.
As a British Crown Dependency, Isle of Man occupies “a unique and liminal space” vis-à-vis climate action: despite being self-governed, it is often aggregated within the UK for data collection purposes, obscuring its (largely) independent status (McCartney, 2023, p. 1134).
Climate change vulnerability and energy security are salient local issues. While several power stations do exist on the island—including Pulrose (a diesel and gas-fired energy plant), Sulby (a hydroelectric plant), Peel (a source of backup/peak demand energy), and a waste-to-energy
plant—Isle of Man imports 92 percent of its energy. Consequently, the subnational entity’s renewable capacity is minimal; the island’s “productive potential” goes largely unrealized (Watt & Wilby, 2025, p. 2). Compounding this, Isle of Man-UK trading relations favor path dependency: potential economic sanctions incentivize the use of (carbonintensive) energy sources with predictable outputs to fulfill expected export quotas.
Isle of Man became the only island jurisdiction to be acknowledged by the UN as a Biosphere Reserve. This protective designation directly shapes climate action: it requires policy to “respect the natural environment” (Watt & Wilby, 2025, p.3) and has propelled peatland restoration, woodland planting, and blue carbon efforts.
Manx climate ambition is also reliant on external expertise. A commissioned report (Curran, 2019) expounds cross-sectoral recommendations to step up climate action. The report author has since served as an external climate policy advisor, (seemingly) shaping climate ambitions by, for example, advocating for a just transition, much as Scotland has.
Comparative Analysis
Policies
As a founding member, Wales exhibits similar legislative activity to—and has even been exceeded by—Scotland and Northern Ireland, reflecting its status as the devolved administration most intertwined with English law (see Fig. 7.1). On plan adoption, Scotland was by far the most active from the early 2010s onward (often exceeding UK ambitions), with Wales adopting the fewest plans. While Isle of Man did not adopt any climate legislation until after 2015—coinciding with the Paris Agreement—and has since remained the least prolific actor, it adopted a (relatively) similar number of plans to the UK devolved administrations before 2010 and has, following a 2012 Scoping Study, accelerated plan adoption.
Notably, all subnational entities exhibited (relatively) low legislative activity levels prior to 2015, indicative of limited devolved competencies and/or capacity constraints. The actors’ higher plan adoption rates exemplify their function as a (relatively) soft indicator of climate ambition. Nonetheless, all four jurisdictions (further) increased legislative activity around the time of the 2015 Paris Agreement and stepped up plan adoption post-2020 after declaring climate emergencies.

Fig. 7.1 Adoption of climate laws and plans

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Despite (only) being an early joiner, Scotland adopted the most climate policies (particularly plans), underscoring its status as a long-standing climate leader, while Wales and Northern Ireland have steadily increased their policy adoption over time. In contrast, Isle of Man has stepped up climate policy adoption more recently and has engaged in substantive planning post-2012. The following subsection expands on these findings, comparing the climate policy adoption of Wales to Scotland, Northern Ireland, and Isle of Man.
Welsh climate policy activity predates its co-founding of U2C. While successive Government of Wales Acts have ceded powers downwards, Welsh climate policy resembles a UK-wide pattern of persistent, yet differentiated, “cross-domain differences”: while “functional pressures” have enabled profound decentralization of some policy areas (waste, building, planning, agriculture), “obstinate centralization” dominates others, especially energy, where Wales has no devolved authority (Tatham & Lemaire, 2024, p. 23).
Despite limited powers, Wales has adopted several innovative climate policies. While some were adopted before co-founding U2C, coalition accession has (seemingly) helped maintain and step up climate ambitions.
Nonetheless, Wales has adopted fewer climate policies than Scotland and Northern Ireland, administrations that are less intertwined with the English legal system.
The Scotland Act 1998 commenced a devolution process which has ceded greater constitutional autonomy to Scotland than other devolved administrations, facilitating “distinctive and ambitious” climate policy development (Royles & McEwen, 2015, p. 1041).
While successive National Planning Frameworks have entrenched crosssectoral climate ambitions, Scottish planning accelerated in the 2010s following legislation of a 2009 Climate Change Act, which exceeds the 2008 UK Act in climate ambition. Scotland’s landmark Climate Change Plan 2018–2032 articulates over 100 policies for a just net-zero transition, while a 2023 National Just Transition Planning Framework formalizes climate justice ambitions.
Overall, Scotland has adopted more climate laws and plans than the three other actors. While several policies were adopted before joining U2C, most were adopted after. U2C membership has even been described as key to “Scotland’s international capacity building engagement” (Scottish Government, 2024, p. 160) and as a tool for stepping up climate action.
In contrast, Northern Ireland has been slow to exhibit climate ambition. It was the last devolved administration to adopt a sustainable development strategy in 2006 (McClenaghan, 2008) and only established its Environment Agency in 2008 (the other UK devolved administrations did so in 1996).
While the Northern Ireland Act 1998 established the nation’s primary governance architecture—the Assembly and the Executive—it did not stipulate climate action. However, the Good Friday (or Belfast) Agreement 1998 enshrined environmental governance as an area of cross-border cooperation.
Climate policy adoption increased after joining U2C, coinciding with the 2020 declaration of a “New Decade, New Approach”, whereby Northern Ireland aligned with the Paris Agreement, published a just transition- focused Energy Strategy, and legislated a 2022 Climate Change Act. The Act codified net-zero by 2050 across three budgetary periods (spanning 2023–2037), 48% emissions reduction targets for 2030 and 2040, and climate action plans every five years.
Overall, while Northern Ireland adopted several climate policies prior to joining U2C, the most consequential, including the Act, were adopted after joining.
Various climate policy developments commenced in 2006 with early recognition of energy- and climate change-related challenges. This was bolstered by a 2010 report describing “significant untapped” renewable energy deployment and export potential. Cross-sectoral reforms and ambitious benchmarks for increasing the share of renewables in the island’s energy mix were outlined in 2013, signifying a shift from exploratory to strategic climate action.
A 2016 climate change mitigation framework moved Isle of Man closer to (inter)national norms (by setting specific transport, buildings, energy, and waste targets) and championed measurable policy outcomes. A 2020 plan necessitated “immediate” GHG emissions reduction, increased natural carbon capture, and operationalization of net-zero pathways analysis. In 2021, shortly after joining U2C, a landmark Climate Change Act legislated net-zero by 2050 and mandated five-year climate action plans. Prior to this, Isle of Man lacked specific climate change legislation or obligations: while the UK Government extended its ratification of the 1997 Kyoto Protocol in 2006 and the 2015 Paris Agreement in 2015 to include Isle of Man, the island has never been subject to the 2008 UK Climate Change Act. A 2022 plan identified energy, transport, residential buildings, and agriculture as key emitting sectors, alongside forestry and land use as a carbon sink. It also articulated cross-sectoral and sector-specific targets alongside an explicit desire to replicate legislative solutions adopted across the UK (including Wales’ intergenerational approach).
Therefore, while Isle of Man articulated broad visions before joining U2C, it adopted more substantive, measurable policies afterward, emulating others.
Policy Instruments
This subsection examines the climate policy instruments adopted by each subnational actor relative to U2C membership (see Fig. 7.2).
Wales responded to its housing stock amassing 21 percent of national carbon emissions and ranking among the oldest and least efficient in Europe by prioritizing energy efficiency measures, including Building and Housing Quality standards.

Fig. 7.2 Policy instruments to reduce regional GHG emissions
It also operationalized various subsidies to incentivize renewable energy generation, increase public sector building energy efficiency, and reduce fuel poverty. Similarly, funding supports public sector energy efficiency and decarbonization projects, while the government provides financial support to public sector organizations and community enterprises working on energy efficiency and renewable energy projects.
Wales prioritized action on waste by adopting 70% (by 2025) and 100% (by 2050) recycling targets (Cowell et al., 2020) and a Circular Economy Fund (although Hobson (2022) describes this as a “rebadging” of preexisting resource governance initiatives). It was also among the first to implement carrier bag charging (Thomas et al., 2016). In 2022, Net Zero Industry Wales was established to support industrial decarbonization, while a Net Zero Challenge Group was established (2023) to commission and share relevant expertise.
Wales has also supported hydropower—including establishing Dinorwig Power Station, a pumped storage hydroelectric power station—given the potential for hydropower to make a significant (about 15 percent) contribution to renewable energy generation capacities (Bere et al., 2017).
Overall, Welsh climate policy instruments target energy- and building- related decarbonization. While some instruments were implemented before co-founding U2C, most were implemented after. Nonetheless, most Welsh policy instruments are technologically specific, mirroring national-level instruments (Wade et al., 2022).
Scotland has adopted an array of climate policy instruments, including flagship fiscal mechanisms to promote climate justice. Between 2008 and 2022, Scotland sponsored a Climate Challenge Fund to support community- scale decarbonization. In 2010, the Scottish government launched the Community and Renewable Energy Scheme which has provided over £58m to over 600 projects.
A 2012 Climate Justice Fund (£24m) positioned Scotland as the first nation to proactively prioritize climate justice. In 2018, Scotland launched a Just Transition Commission to scrutinize relevant plans. In 2021, Scotland committed to treble its Climate Justice Fund contribution (£36m until 2026), while as COP26 host nation, it became the first global North country to pledge finance (one million pounds) to address Loss and Damage.
In 2022, Scotland announced a 180 million pounds Emerging Energy Technologies Fund to develop hydrogen and carbon capture and storage sectors between 2022 and 2026. This fund included a 10 million pounds stream to support renewable hydrogen solutions. This was bolstered in 2023 by a 90 million pounds Green Hydrogen Fund. Scotland has prioritized vehicle fleet decarbonization, contributing to an U2C-affiliated ZEV Community to accelerate ZEV uptake by sharing best practices. Finally, Scotland has prioritized peatland restoration since 2012, recognizing that this significant carbon sink covers over 20 percent of Scottish land (Ferretto et al., 2019).
In summary, Scotland has adopted various policy instruments to reduce GHG emissions, aided by its 2009 Climate Change Act and U2C membership. Several instruments (e.g., on climate justice) were implemented before joining U2C and others afterward (e.g., a Loss and Damage Fund).
Northern Ireland has introduced a limited number of policy instruments, including a 2010 8 million pounds Sustainable Energy Program, 80 percent of which supports implementation of domestic/business energy efficiency schemes through boiler upgrades, low-emission light fitting, and insulation installation for vulnerable individuals. It also adopted energy efficiency standards for new public authority buildings in 2019— expanding this to public and private buildings in 2020—prioritized peatland restoration, and, in 2020, committed to planting 18 million trees on 9000 hectares of new woodland by 2030. A 2022 Northern Ireland Climate Change Act created a Just Transition Commission (to develop climate resilient, environmentally sustainable jobs and low carbon investment) and a Just Transition Fund for Agriculture (to provide specific advice and financial assistance), echoing the activities of Wales and Scotland.
Despite being the smallest UK devolved administration, Northern Ireland wields significant power over energy (Muinzer & Ellis, 2017). This, however, has sparked controversy, exemplified by a 2012 Renewable Heat Incentive Scheme designed to “stimulate increased derivation of heat from renewable sources” (Muinzer, 2017). Despite successful rollout across other parts of the UK, Northern Ireland adjusted the scheme’s financial mechanisms in a maladaptive way, introducing inappropriate tariffs (subsidy rates were set higher than the cost of wood pellets, incentivizing businesses to burn pellets to earn money), and overlooking cost controls (no budget cap or tiered payment schemes were implemented), and oversight mechanisms (which enabled abuse of the system, including intentional overheating of empty farm buildings). These shortcomings shaped a projected overspend of about 490 million pounds (over 20 years), derision of the scheme as “Cash for Ash”, and the 2017 collapse of the devolved government.
Overall, Northern Irish climate policy instruments focused on the energy, waste, and forestry and land use sectors. While measures were implemented before joining U2C, Northern Ireland’s Climate Act was adopted afterward and stipulates several ambitious policy instruments (e.g., on climate justice). However, these are (largely) still to be implemented.
Isle of Man introduced climate policy instruments at a slower rate than the devolved administrations analyzed in this chapter. Instruments include a 2018 Sustainable Financing Framework (financing expenditure by issuing climate bonds), a 2018 Energy Efficiency Scheme (to incentivize low- carbon home improvements), and a 2021 Green Living Grant Scheme (to lower residential carbon emissions and energy bills through home energy audit and grant support). The government moved to institutionalize climate ambition in 2020 by forming a Climate Change Transformation team, establishing two climate funds—on Environment Protection and a Climate Change Mitigation—and prohibiting peat extraction from the island’s only public turbary.
In 2024, Isle of Man introduced renewable energy and sustainable technology training, government carbon literacy training, and a carbon credit project focused on natural carbon sequestration (whereas Wales, Scotland, and Northern Ireland contribute to EU/UK emissions trading schemes).
Finally, Isle of Man introduced several bans, including a 2023 ban on the sale, supply, and distribution of ten single-use plastics (following an EU directive), a 2024 (temporary) ban on bottom trawling three fishing sites, and a 2025 ban on fossil fuel heating system installation in new buildings.
Overall, Isle of Man adopted several specific instruments to reduce GHG emissions, most of which were introduced after joining U2C.
Targets
The following section explicates the GHG emissions reduction targets adopted by each subnational government. Unless specified otherwise, targets refer to a 1990 emissions reduction baseline.
All four jurisdictions adopted targets with various time frames (see Fig. 7.3). Short- and medium-term targets are considered the most ambitious as they put immediate pressure on policymakers to take action. The findings exhibit no clearly discernable link between U2C membership and target adoption. While Scotland adopted all three target types in 2009 before U2C participation, Wales adopted short- and long-term targets shortly after co-founding U2C (seemingly leveraging it to counteract

Fig. 7.3 Greenhouse gas emissions reduction targets constitutional capacity constraints), while Northern Ireland adopted short- and long-term targets shortly after joining in 2021, and Isle of Man set short- and long-term targets before joining in 2021, and adopted a medium-term target shortly after.
In short, while U2C membership may aid target adoption, this is often also shaped by subnational political, institutional, and legal factors. While Northern Ireland and Isle of Man exhibit some followership traits (by adopting targets shortly after joining U2C), Scotland has shouldered significant responsibilities within the coalition (as European co-chair) and was the first to adopt targets across all time frames (including a 2009 net- zero target).
The findings partially support the central propositions of this book presented in Chap. 2: that founding (and early) U2C members set more ambitious climate targets than later joiners due to stronger reputational incentives. The remainder of this subsection details the targets adopted by each subnational entity.
Wales adopted ambitious targets prior to co-founding U2C. In 2010— under the 2008 UK Climate Change Act, the primary legislative framework operating in Wales at the time (Muinzer, 2019)—Wales committed to 3% annual emissions reductions across areas of devolved competence vis-à-vis a 2006–2010 baseline. This covered about 70% of Welsh emissions, reflecting shared climate policy competencies across Assembly (about 30%) and UK and EU (about 40%) decision-making arenas. The remaining about 30% of emissions were to be realized by Welsh businesses, the public sector, and community actions. A GHG emissions reduction target of 40% by 2020 covering all Welsh GHG emissions was adopted in 2010, alongside sector-specific targets.
Welsh target-setting stepped up following adoption of the 2016 Environment (Wales) Act, which legislated emissions reduction targets of 45% by 2030, 67% by 2040, and 80% by 2050 as well as five-yearly carbon budgets.
In 2019, Wales adopted three cross-sectoral GHG emissions reduction targets: (1) 27% by 2020; (2) 45% by 2030; and (3) 67% by 2040. In 2021, following the UK’s Climate Change Committee’s (CCC; for details, see Seibicke, 2025) advice (2020), Wales adopted more ambitious tar- gets—63% by 2030, 89% by 2040, and net-zero GHG emissions by 2050—plus corresponding carbon budgets covering 2021–25 (about 37% reduction) and 2026–30 (about 58% reduction).
Overall, Wales has adopted increasingly ambitious targets. While several targets were set prior to U2C co-founding, target-setting stepped up post-2016.
After implementing a 2009 Climate Change Act, Scotland set comprehensive, annual net-zero targets for 2010–2022 to facilitate regular scrutiny of progress. In 2023, further annual targets were set for 2028–2032. An updated 2019 Act—including a headline net-zero commitment by 2045 (up from 90% by 2050) and five years ahead of the UK—ratcheted up Scotland’s ambitions. Interim targets were also set, including a 75% GHG emissions reduction by 2030 (up from 66%) and 90% by 2040 (up from 75%).
In 2017, Scotland pledged to collaborate with U2C co-founder California to step up subnational climate action (by sharing best-practice offshore wind solutions) in response to President Donald Trump’s diminution of US national-level climate action. A 2022 CCC review recommended adjusting Scotland’s annual targets to reflect significant changes to the treatment of peatland emissions within emissions inventories. In response, Scotland revised its 2021–2029 targets accordingly.
The CCC went further in 2024, describing Scotland’s 2030 climate goals—specifically its 75% GHG emissions reduction target—as lacking credibility. Ultimately, it failed to meet 9 of the 13 targets adopted between 2010 and 2013 under the 2009 Act.
To restore credibility, Scotland withdrew its 2030 and 2040 interim targets and committed to drawing up new carbon budgets every five years for the period covering 2026–2045, emulating (sub)national approaches in the UK and Wales. Multi-year carbon budgets were deemed appropriate given the susceptibility of annual targets to annual GHG emissions fluctuations. Despite these changes, Scotland retained its headline net-zero GHG emissions by 2045 target.
In summary, Scotland has adopted targets with varying temporal horizons. While some were set before joining U2C (aided by stability provided by the 2009 Climate Change Act), others were adopted after. Scottish target-setting is intertwined with CCC guidance: while ambitions have regularly exceeded those of other UK devolved administrations, they have also been critiqued as overly ambitious.
Northern Ireland adopted GHG emissions reduction targets in 2007, committing to a 25% carbon footprint reduction by 2025. In 2011, Northern Ireland committed to a GHG emissions reduction of at least 35% by 2025. After joining U2C in 2021, Northern Ireland committed to an 82% GHG emissions reduction by 2050.
The 2022 Northern Ireland Climate Change Act legislated a net-zero GHG emissions target by 2050 (although methane was not required to be reduced by more than 46%). In 2024, two statutory instruments stipulated successive carbon budgets at an average annual reduction of 33% (2023–27), 48% (2028–31), and 62% (2033–37), as well as a GHG emissions reduction target of 77% by 2040.
Northern Ireland has therefore adopted progressively ambitious targets, supported by increasingly ambitious legislative solutions. Of these, one target was set before joining U2C and the rest afterward, reflecting a receding tendency to prioritize economic development over climate action.
Isle of Man formulated early targets, including a 2013 target of reducing GHG emissions by 80%. Over time, targets have become increasingly ambitious and precise.
In 2021, a landmark Climate Change Act legislated a net-zero emissions target by 2050 relative to a 2018 baseline, emulating the UK. A 2022 Strategy set two intermediate targets, namely, (1) a 35% GHG emissions reduction by 2030 and (2) a 45% one by 2035.
Overall, while a GHG emissions reduction target was set before joining U2C, increasingly ambitious targets were adopted after joining, (seemingly) to emulate other subnational actors.
Leadership
All four UK subnational governments used U2C membership to maintain and/or step up climate ambitions to varying degrees, displaying distinct, context-specific leadership/followership trajectories.
As a self-proclaimed climate leader (Irranca-Davies, 2024), Wales presents strong normative and cognitive leadership anchored in long-term thinking. The Wellbeing of Future Generations (Wales) Act 2015 garnered international recognition by embedding intergenerational equity into law and even influenced the UN Pact for the Future (Irranca-Davies, 2024). However, despite being a U2C co-founder, Wales enacted fewer climate policies than its devolved counterparts: structural constraints, including entanglement with English law, hindered its ability to decisively legislate. This finding aligns with portrayals of Welsh climate leadership as hampered by a lack of “implementation mechanisms” (Newman et al., 2024, p. 11) and centrally determined, annualized budgets (Wallace, 2019)	. Burns et al. (2018, p. 8) even caution against uncritical appraisal of Welsh climate ambitions, citing poor performance on issues including air quality. Nonetheless, Wales (broadly) exhibits climate leadership (notably on climate justice) and has used U2C, where feasible, to step up climate action.
As an early joiner, Scotland offers a contrasting example of climate leadership (McEwen & Bomberg, 2014; Royles & McEwen, 2015): adopting the most climate policies, adopting ambitious GHG emissions targets, leading on climate justice implementation, and even launching a Loss and Damage Fund. These activities are intertwined with a broader political narrative: policy-based climate action bolsters independence aspirations by exceeding national-level ambitions. However, this approach has limitations: multiple missed annual targets prompted a 2024 switch to carbon budgets every five years, resembling followership (by emulating UK and Welsh approaches).
Northern Ireland only recently demonstrated climate leadership potential: delayed U2C engagement reflects historic policy fragmentation and political instabilities centered around post-conflict recovery. Northern Ireland’s landmark 2022 Climate Act is indicative of wider climate policy emulation. While past environmental crises and scandals highlight enduring risks to credibility, a distinct opportunity remains to realize growing public expectations on climate action.
While Isle of Man stepped up climate action in the 2020s, it resembles a climate follower. U2C membership coincided with a wider proliferation of climate policy activity, including legislation of a 2021 Climate Act. Cognitive and entrepreneurial leadership was also limited: external expertise informed prioritization of climate justice, emulating exemplary Scottish leadership on this issue. In short, despite capacity constraints, Isle of Man leveraged protective designation, external expertise, and U2C membership to step up action.
Ultimately, all four subnational governments displayed different modes of climate leadership and/or followership, using U2C membership to shape climate ambitions to varying degrees. This illustrates that while U2C membership can shape policy-based climate action, subnational contexts also matter.
Conclusion
This chapter examined the extent to which a U2C co-founder (Wales) adopted more ambitious climate policies, instruments, and targets than one early joiner (Scotland) and two later joiners (Northern Ireland and Isle of Man). With reference to the existing literature on leadership and followership, it has addressed the central proposition of this book: that founding (and early) members face the strongest reputational incentives vis-à-vis later joining national counterparts due to a drive to maintain and enhance reputations as climate leaders.
The overall findings are mixed. While Welsh climate ambition (largely) exceeds that of later joiners (Northern Ireland and Isle of Man), Scotland, an early joiner, demonstrates the greatest climate ambition. Although Wales demonstrably used U2C to articulate leadership ambitions (e.g., on a just transition; Irranca-Davies, 2024), Scotland also resembles a climate leader despite (only) being an early joiner, and it remains to be seen whether Welsh climate justice ambitions are simply emulating Scotland’s pioneering work on this issue prior to joining U2C.
This reflects the complexities of the UK climate governance landscape in a microcosm, underlining the consequential nature of devolved autonomy and landmark climate acts for maintaining and stepping up climate action. While U2C membership may well provide (varied) reputational incentives to develop distinct “climate actorness”, the corresponding ability to seize opportunities to step up climate ambitions is context-specific.
Scotland exhibited the greatest climate policy ambition of all four actors, epitomized by its leadership role as European U2C co-chair. This activity is closely intertwined with historic state-building ambitions and comparatively greater devolved autonomy. In contrast, Northern Ireland and Isle of Man were slower to embrace climate action, prioritizing postconflict economic recovery and internal capacity constraints, respectively. Nonetheless, both subnational entities raised their climate policy ambitions after joining U2C by legislating landmark climate acts, indicative of climate followership.
Overall, it remains difficult to definitively disentangle the extent to which U2C membership provides a mechanism for climate leadership and/or followership associated with reputational incentives, as the increase in climate policy adoption following U2C participation might simply reflect the growing salience of subnational climate action post Paris. Future research should explore this as a priority.
References
Barry, J. (2009). ‘It ain’t easy being green’: Sustainable development between environment and economy in Northern Ireland. Irish Political Studies, 24(1), 45–66. https://doi.org/10.1080/07907180802551084
Bere, J., Jones, C., Jones, S., & Munday, M. (2017). Energy and development in the periphery: A regional perspective on small hydropower projects. Environment and Planning C: Politics and Spaces, 35(2), 355–375. https:// doi.org/10.1177/0263774X16662029
Brennan, C., Purdy, R., & Hjerp, P. (2017). Political, Economic and Environmental Crisis in Northern Ireland: The True Cost of Environmental Governance Failures and Opportunities for Reform. Northern Ireland Legal Quarterly, 68(2), 123–158.
Burns, C. J., Carter, N., Cowell, R., Eckersley, P., Farstad, F., Gravey, V., Jordan, A., Moore, B., & Reid, C. (2018). Environmental policy in a devolved United Kingdom. Challenges and opportunities after Brexit. https://irep.ntu.ac.uk/ id/eprint/34975/
Carter, N., & Pearson, M. (2024). From green crap to net zero: Conservative climate policy 2015–2022. British Politics, 19(1), 154–174. https://doi. org/10.1057/s41293- 022- 00222- x
Cowell, R. (2017). Decentralising energy governance? Wales, devolution and the politics of energy infrastructure decision-making. Environment and Planning C, 35(7), 1242–1263. https://doi.org/10.1177/0263774X16629443
Cowell, R., Flynn, A., & Hacking, N. (2020). Conceptualising environmental governance in turbulent times: Insights from Brexit and waste in the UK. Political Geography,	81, 102217.	https://doi.org/10.1016/j. polgeo.2020.102217
Curran, J. (2019). IMPACT (IoM Programme for Achievement of Climate Targets) https://www.gov.im/media/1368097/gd20190102_james-curran- report.pdf.
Diamond, P., Newman, J., Richards, D., Sanders, A., & Westwood, A. (2024). ‘Hyper-active incrementalism’ and the Westminster system of governance: Why spatial policy has failed over time. The British Journal of Politics and International Relations, 26(4), 1185–1210. https://doi. org/10.1177/13691481241259385
Ferretto, A., Brooker, R., Aitkenhead, M., Matthews, R., & Smith, P. (2019). Potential carbon loss from Scottish peatlands under climate change. Regional Environmental Change, 19(7), 2101–2111. https://doi.org/10.1007/ s10113- 019- 01550- 3
Gravey, V., Ruddock, D., & McCallister, J. (2025). Review of environmental governance in Northern Ireland interim report | Department of Agriculture, Environment and Rural Affairs. DEARA. https://www.daera-ni.gov.uk/pub- lications/review- environmental- governance- northern- ireland-interim- report
Hobson, K. (2022). The limits of the loops: Critical environmental politics and the Circular Economy. In Trajectories in Environmental Politics. Routledge.
Hwang, J. (2024). After Mobuoy: Co-designing environmental governance in Northern Ireland? Irish Political Studies, 39(1), 24–46. https://doi.org/1 0.1080/07907184.2023.2254259
Irranca-Davies, H. (2024, October 1). Written statement: Wales’s global climate leadership. https://www.gov.wales/written- statement- waless- global- climate- leadership
Liefferink, D., & Wurzel, R. K. W. (2017). Environmental leaders and pioneers: Agents of change? Journal of European Public Policy, 24(7), 951–968. https:// doi.org/10.1080/13501763.2016.1161657
McCartney, C. (2023). SDG advocacy on the Isle of Man: Business versus biosphere perspective. In W. Leal Filho, M. A. P. Dinis, S. Moggi, E. Price, & A. Hope (Eds.), SDGs in the European region (pp. 1133–1176). Springer International Publishing. https://doi.org/10.1007/978- 3- 031- 17461- 2_74
McClenaghan, A. (2008). Ecological modernisation in the UK: Northern Ireland’s sustainable development strategy in context. Environmental Politics, 17(5), 804–814. https://doi.org/10.1080/09644010802422537
McEwen, N., & Bomberg, E. (2014). Sub-state climate pioneers: The case of Scotland. Regional & Federal Studies, 24(1), 63–85. https://doi.org/10.108 0/13597566.2013.820182
Messham, E., & Sheard, S. (2020). Taking the long view: The development of the Well-being of Future Generations (Wales) Act. Health Research Policy and Systems, 18(1), 33. https://doi.org/10.1186/s12961- 020- 0534- y
Moulton, J. F. G. (2020). Lessons from climate action in the UK: The limitations of state leadership. In R. K. W. Wurzel, M. S. Andersen, & P. Tobin (Eds.), Climate governance across the globe (pp. 182–199). Routledge.
Muinzer, T. L. (2017). Incendiary developments: Northern Ireland’s Renewable Heat Incentive, and the collapse of the devolved government. Elaw Newsletter, 99. https://dspace.stir.ac.uk/handle/1893/26067
Muinzer, T. L. (2019). Climate and energy governance for the UK low carbon transition: The climate change act 2008. Springer International Publishing. https:// doi.org/10.1007/978- 3- 319- 94670- 2
Muinzer, T. L., & Ellis, G. (2017). Subnational governance for the low carbon energy transition: Mapping the UK’s ‘Energy Constitution’. Environment and Planning C, 35(7), 1176–1197. https://doi.org/10.1177/2399654416687999
Nash, S. L. (2021). ‘Anything Westminster can do we can do better’: The Scottish climate change act and placing a sub-state nation on the international stage. Environmental Politics, 30(6),	1024–1044. https://doi.org/10.108 0/09644016.2020.1846957
Newman, J., Mukherjee, A., & Hoole, C. (2024). Constraints and enablers of regional environmental policy: Governance challenges in England and Wales. Journal of Environmental Policy & Planning, 26(1), 1–13. https://doi.org/1 0.1080/1523908X.2023.2297793
Rayner, T., & Jordan, A. (2010). The United Kingdom: A paradoxical leader? In The European Union as a leader in international climate change politics. Routledge.
Royles, E., & McEwen, N. (2015). Empowered for action? Capacities and constraints in sub-state government climate action in Scotland and Wales. Environmental Politics, 24(6),	1034–1054. https://doi.org/10.108 0/09644016.2015.1053726
Santos Ayllón, L. M., & Jenkins, K. E. H. (2023). Energy justice, just transitions and Scottish energy policy: A re-grounding of theory in policy practice. Energy Research & Social Science, 96, 102922. https://doi.org/10.1016/j. erss.2022.102922
Scottish Government. (2024). Climate change: Scottish National Adaptation Plan 2024–2029.	https://www.gov.scot/publications/ scottish- national- adaptation- plan- 2024- 2029- 2/
Seibicke, H. (2025). The Institutional Design of Scientific Advisory Boards on Climate Change: A Comparison at the Intergovernmental, Supranational, and National Level. Global Challenges, 9(9), 1–11. https://doi.org/10.1002/ gch2.202400371
Tatham, M., & Lemaire, P. (2024). Mapping domestic climate authority: Insights from the UK’s multi-scale institutional architecture. British Politics, 20, 549–576. https://doi.org/10.1057/s41293- 024- 00268- z
Thomas, G. O., Poortinga, W., & Sautkina, E. (2016). The Welsh Single-Use Carrier Bag Charge and behavioural spillover. Journal of Environmental Psychology, 47, 126–135. https://doi.org/10.1016/j.jenvp.2016.05.008
Toulmin, C. (2025, May 1). What is a just transition for Scotland? The global policy response. Royal Society of Edinburgh. https://rse.org.uk/resource/ what-i s- a- just- transition- for- scotland- the- global- policy- response/
Wade, F., Webb, J., & Creamer, E. (2022). Local government capacities to support net zero: Developing comprehensive heat and energy efficiency strategies in Scotland. Energy Research & Social Science, 89, 102544. https://doi. org/10.1016/j.erss.2022.102544
Wallace, J. (2019). Wales: Wellbeing as sustainable development. In I. J. Wallace (Ed.), Wellbeing and devolution (pp. 73–101). Springer International Publishing. https://doi.org/10.1007/978- 3- 030- 02230- 3_4
Watt, B., & Wilby, R. L. (2025). A whole island approach to scoping renewable energy sites and yields. Area, 57(2), e70003. https://doi.org/10.1111/ area.70003
Williams, P. (2006). The governance of sustainable development in Wales. Local Environment, 11(3), 253–267. https://doi.org/10.1080/13549830 600558754
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CHAPTER 8	
Comparative Assessment
Abstract This chapter provides a comparative assessment of climate policies, policy instruments, and greenhouse gas emissions reduction targets across subnational jurisdictions in the United States, Canada, Germany, Spain, and the UK that joined the Under2 Coalition at different timepoints. The analysis reveals that while founding members generally demonstrate sustained climate policy effort, the relationship between membership timing and climate ambition is mediated by domestic political contexts, institutional capacity, and structural factors. Under2 Coalition membership functions primarily as an amplifying mechanism rather than a transformative catalyst, reinforcing existing climate policy trajectories through reputational incentives, policy learning networks, and international visibility. Evidence of policy diffusion emerges through adoption of California’s vehicle emission standards, institutional emulation of climate laws, and transfer of innovative mechanisms like Scotland’s Climate Justice Fund. However, some early joiners match or exceed founding member performance, while certain later joiners demonstrate a remarkable acceleration of policy-based climate action, challenging simple assumptions about first-mover advantages. Political transitions, constitutional arrangements, and economic factors prove more decisive than coalition entry sequencing in determining actual policy outcomes.

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© The Author(s) 2026
J. Tosun et al., Subnational Climate Leadership Dynamics Among Under2 Coalition Members, Palgrave Studies in Sub-National
Governance, https://doi.org/10.1007/978-3-032-12610-8_8
Keywords Comparative climate governance • Institutional capacity • Policy diffusion • Political dynamics • Under2 Coalition
Introduction
In this chapter, we focus on the comparative assessment of the climate policies, policy instruments, and targets for reducing GHG emissions across these diverse subnational jurisdictions investigated in Chaps. 3 through 7. We discuss the insights for the leadership-focused dimension of our analysis in Chap. 9, where readers will find a detailed exploration of how different types of climate leadership manifest across the case studies.
The comparative empirical findings reveal a complex picture, where timing of U2C accession matters yet it is mediated by domestic political contexts, institutional capacity, and structural factors specific to each region. While founding members generally demonstrate sustained climate policy effort, some early joiners match or exceed their effort, and certain later joiners show remarkable acceleration in policy-based climate action post-membership.
United States
Founding Members
In the United States, founding members exhibited the most sustained policy effort, with California leading with more than 40 policies in place by 2024. All founding members increased their climate policy activity post-2015, though California’s policy trajectory was already steep pre- U2C. Vermont and Washington showed the most dramatic policy growth after co-founding U2C, while Oregon’s was more gradual. California also deployed the most comprehensive mix of policy instruments. Other US founding members introduced fewer new instruments post-2015, suggesting U2C membership reinforced existing trajectories rather than fundamentally redirecting them. All founding members established comprehensive GHG emissions reduction targets early, with California setting 2030 and 2045 benchmarks that influenced targetsetting by other US states.
Early Joiners
Connecticut, Massachusetts, Minnesota, New Hampshire, New York, and Rhode Island—as the group of early joiners—exhibited markedly varied climate policy trajectories, with some matching founding members’ performance while others lagging far behind.
Massachusetts and New York emerged as the early joiners that demonstrated the highest level of climate policy ambition, with Massachusetts accumulating the highest number of policies among all studied states. Both states leveraged existing RGGI participation and robust state capacity to expand comprehensive climate policy frameworks post-2015. New York’s Climate Leadership and Community Protection Act (2019) mandates zero-emissions electricity by 2040 and exemplifies how early joiners could exceed the climate policy ambition of founding members. Massachusetts similarly built on its foundational 2008 Global Warming Solutions Act through successive climate plans and its landmark 2021 Next-Generation Roadmap legislation.
Connecticut and Rhode Island showed steady but more modest progress. Connecticut pioneered climate finance innovation through the nation’s first state green bank (2011). However, the state’s withdrawal from the Transportation & Climate Initiative in 2021 and its postponed adoption of California’s Advanced Clean Cars II revealed limitations in sustained ambition. Rhode Island maintained consistent participation in regional initiatives, such as the RGGI, while gradually strengthening its legal framework through its 2021 Act on Climate.
New Hampshire failed to adopt binding GHG emissions reduction targets or meaningful EV programs despite early U2C membership. Minnesota experienced a prolonged plateau (2008–2018) before momentum resumed, missing its 2015 targets and only aligning with peer net- zero commitments in 2023.
Early joiners showed diverse instrument adoption patterns. Massachusetts and New York each implemented 7–8 instrument types, including standards, cap-and-trade, subsidies, and information measures. Connecticut’s green banking model was an innovative financial instrument that later diffused nationally. However, several early joiners relied heavily on federal and regional frameworks, particularly the RGGI, rather than developing distinct, state-level innovations.
Target adoption by the early joiners varied significantly. Massachusetts and New York adopted binding statutory targets early and strengthened them post-U2C accession. New Hampshire notably lacked any binding GHG targets, representing clear followership failure.
Later Joiners
Colorado pioneered methane regulations for oil and gas operations (2014) that later influenced federal policy, while Hawaii’s early binding GHG emissions reduction targets (2007) and 100% renewable electricity mandate (2015) positioned it as a climate leader well before joining U2C in 2018.
Maine and New Jersey displayed resurgence patterns following Republican gubernatorial periods that stalled climate action. Maine’s climate governance stagnated under Governor Paul LePage (2011–2018) before accelerating rapidly under Governor Janet Mills, who joined Maine to U2C (2021) and passed comprehensive climate legislation. New Jersey similarly paused climate action under Governor Chris Christie (2010–2018) before re-entering the RGGI and adopting ambitious offshore wind targets under Democratic leadership.
Nevada adopted minimal climate policies until 2019, when it established renewable energy standards and ZEV requirements. The state’s late but intensive policy burst demonstrates how later joiners can quickly catch up given sufficient political will.
Virginia illustrated the vulnerability of later adopters to political backsliding. Despite joining U2C in 2017 and enacting comprehensive climate legislation before 2022, Glenn Youngkin’s Republican gubernatorial victory resulted in attempted withdrawal from the RGGI and the decision to halt adoption of Californian vehicle standards, highlighting the fragility of late-developing climate frameworks.
Most later joiners showed limited instrument diversification compared to founding members and proactive early joiners. Energy generation and building standards dominated, with fewer comprehensive, economy-wide approaches. However, several adopted innovative instruments, like Nevada’s renewable energy storage requirements and Maryland’s environmental justice provisions in climate legislation.
Few late joiners adopted short-term targets, reflecting lower immediate accountability pressure. However, medium- and long-term targets proliferated post-U2C membership, particularly net-zero by 2050.
Canada
Founding Members
British Columbia established comprehensive climate policies before cofounding U2C. In particular, its landmark 2008 Climate Plan introduced three transformative instruments: a carbon tax, the Clean Energy Standard banning coal generation, and the Low Carbon Fuel Standard. The province expanded its policy framework post-2015 through the CleanBC program, garnering U2C recognition for innovative climate solutions. However, political volatility undermined sustained leadership—the carbon tax was repealed in 2025 despite initial success in reducing GHG emissions.
Ontario’s early policy innovations included a coal phase-out (completed 2014), feed-in-tariff programs, and the Green Energy and Green Economy Act (2009). The province briefly joined the California-Québec cap-and-trade system (Western Climate Initiative) in 2018, but the 2018 Progressive Conservative Party’s victory in the provincial elections led to withdrawal from the cap-and-trade program, the cancelation of 750 renewable energy projects, and elimination of the GEGEA entirely, showing how electoral transitions can rapidly reverse climate progress.
Both Canadian jurisdictions implemented carbon pricing mechanisms, though design varied significantly. British Columbia led with early carbon taxes and cap-and-trade, while Ontario’s brief participation demonstrated regional integration potential. Both founding members adopted comprehensive GHG emissions reduction targets early. However, in the case of Ontario, policy durability proved challenging given partisan opposition and economic framing of climate policies as burdens rather than opportunities.
Early Joiner
In 2014, Québec and California linked their cap-and-trade programs, creating North America’s first multisectoral carbon market. Québec also pioneered ZEV mandates in 2016, becoming the first Canadian province to establish ZEV requirements without major automotive industry presence. Québec adopted multiple climate policies between 2001 and 2023, with several sector-specific initiatives (ZEVs and sustainable mobility) emerging after U2C accession. The province established medium- and long-term GHG emissions reduction targets and became an early adopter of net-zero commitments (2020), though implementation remains intertwined with large infrastructure projects.
Later Joiner
The Northwest Territories exhibited limited legislative activity compared to the Canadian foundering members, adopting the lowest number of climate policies while producing the most climate plans of all Canadian jurisdictions. This pattern reflects territorial focus on strategic planning over binding policies, with successive Greenhouse Gas Strategies (2001–2015) prioritizing corporate emissions over jurisdiction-wide targets.
The territory’s policy instruments remained limited but innovative, focusing on community-specific solutions like the Capital Asset Retrofit Fund and Arctic Energy Alliance. The 2012 Energy Charrette represented successful multi-stakeholder consensus-building around renewable energy transitions, while subsequent carbon pricing (2019) included extensive exemptions recognizing northern economic realities.
Target adoption showed late but accelerating ambition: Northwest Territories established long-term GHG emissions reduction goals only after joining U2C.
Germany
Founding Member
Baden-Württemberg emerged as Germany’s strongest and most consistent climate leader, demonstrating sustained ambition both before and after co-founding U2C in 2015. Post-U2C foundation, Baden- Württemberg sustained momentum through revised renewable heating legislation (2023), an updated Climate Protection and Climate Change Adaptation Act (2023), and sector-specific strategies spanning freight transport, public transit, waste management, and energy planning. It implemented Germany’s most comprehensive policy instrument mix, including the first state-level carbon shadow price for government buildings (2023) as well as extensive information services through the Climate Protection and Energy Agency. In 2013 Baden-Württemberg established one of the first legally binding state-level GHG emissions reduction targets in Germany.
Early Joiners
North Rhine-Westphalia initially defied expectations by adopting Germany’s first comprehensive climate protection law (2013) despite heavy coal dependence and large industrial sectors. Schleswig-Holstein leveraged coastal advantages for wind power leadership, adopting ambitious renewable energy goals and comprehensive energy transition legislation (2017). The state exhibited sustained policy effort before and after U2C membership, though sectoral diversification beyond energy generation and efficiency remained limited.
Hesse combined early leadership with municipal support strategies, establishing energy efficiency frameworks and substantial funding programs. The state was slower to adopt binding climate legislation, waiting until 2023 despite the adoption of earlier sustainability strategies. Thuringia initially lagged behind the other early joiners but significantly raised its level of ambition following ratification of the Federal Climate Protection Law in 2018. The state became particularly active in 2024 with the adoption of multiple sectoral sustainability plans and wind energy participation legislation. Bavaria was slow to adopt binding GHG emissions reduction targets (2020 Climate Protection Law) and implemented fewer policy instruments than its peers.
Early joiners showed varied instrument adoption. North Rhine- Westphalia and Hesse led with comprehensive subsidy programs and regulatory standards, while Schleswig-Holstein focused on energy-specific instruments. Most states implemented photovoltaic installation requirements and energy efficiency standards post-2015, suggesting U2C accession reinforced existing trajectories.
Target adoption varied significantly among the early joiners. Most established medium- and long-term targets after joining U2C, with timing correlating to legislative frameworks and Green Party participation in government.
Later Joiners
Lower Saxony showed low overall policy activity and adopted a Climate Protection Act (2020) that neglected major sectors like agriculture and transport. The state implemented fewer policy instruments compared to earlier joiners, focusing primarily on renewable energy subsidies and, recently, building efficiency standards. It adopted a carbon shadow price for government purchases, following Baden-Württemberg’s model, but overall instrument diversification remained limited.
Rhineland-Palatinate adopted Germany’s third comprehensive Climate Protection Act in 2014, preceding most early joiners, and maintained high policy activity through successive sustainability strategy updates and sectoral legislation. Rhineland-Palatinate’s 2025 Climate Protection Law revision established carbon neutrality targets for 2035 and created binding control mechanisms with economic incentives. The state implemented diverse policy instruments including solar installation requirements (2021) and carbon shadow pricing, demonstrating a comprehensive approach despite late coalition membership.
Spain
Founding Member
Catalonia laid the foundations of its climate policy with its Framework Plan for Climate Change Mitigation (2008–2012), which brought together 800 individuals and 500 organizations to build consensus around climate action. The region integrated energy and climate policy through its 2012–2020 Energy and Climate Change Plan, subordinating energy choices to GHG emissions reduction targets. In 2017, Catalonia adopted Spain’s first regional climate framework, establishing net-zero targets by 2050 and comprehensive sectoral measures. Despite constitutional challenges that struck down key provisions in 2019, Catalonia demonstrated resilience through rapid recovery via Decree Law 16/2019, which revived mandates and streamlined renewable energy deployment and set new targets.
Catalonia adopted short-, medium-, and long-term GHG emissions reduction targets before and after founding U2C, further signifying its sustained ambition to take climate action.
Early Joiners
The Basque Country adopted the legislative projects EcoEuskadi 2020 (2011) and KLIMA 2050 (2015) as well as comprehensive sectoral plans, culminating in two climate laws: the Public Administration Energy Sustainability Law (2019) and the foundational Energy Transition and Climate Change Law (2024). Policy instruments were limited but strategically focused: early smart-grid public-private partnerships (2011), binding fiscal tools (2021), and innovative emissions monitoring using satellite technology (2022). Target evolution showed accelerating ambition: from 14% emissions above 1990 levels (2008–2012) to legally binding net-zero by 2050 with 45% reduction by 2030.
In 2010, the Foral Community of Navarre adopted the Climate Change Strategy, which, however, was revoked within months by the regional parliament. Then in 2018, it established long-term objectives for GHG emissions reduction by 2030 and 2050 and introduced fiscal instruments that generated €3.5 million for environmental action. The 2022 Climate Change and Energy Transition Law deferred most binding measures by two to eight years and failed to meet first-year targets. The Foral Community of Navarre implemented diverse policy instruments including taxes, public procurement, and standards, but these were faced by opposition. The 2019 Climate Emergency Declaration proved largely symbolic. Target ambition surged from a 45% reduction by 2030 (2017) to 55% by 2030 and carbon neutrality by 2040.
Later Joiners
Andalusia was Spain’s first region to adopt GHG emissions reduction standards, certifications, and training programs. Two years after joining U2C, it also established binding frameworks that enabled the implementation of the 2021–2030 Climate Action Plan. Nonetheless, Andalusia adopted a limited set of policy instruments post-U2C membership, focusing on consolidating existing approaches rather than innovation. GHG emissions target evolution showed accelerating ambition from an 18% reduction (2018) to 55% (2022) by 2030.
The Community of Madrid adopted policy frameworks spanning energy planning (2004–2012), efficiency standards (2017–2022), and comprehensive decarbonization strategies (2021–2024). After entering U2C in 2019, it adopted the Energy, Climate and Air Strategy (2023–2030), aligning with international frameworks while maintaining focus on technical increments rather than transformative reframing. The region implemented diverse policy instruments primarily in 2023, including subsidies, standards, and voluntary agreements. Progression in its GHG emissions reduction targets remained incremental (20% to 23% by 2030).
Galicia demonstrated the most dramatic late-joiner transformation, strategically timing U2C accession during COP 26 (2021) to leverage global visibility for domestic reform acceleration. The timing of accession coincided with the adoption of Integrated Regional Plans aiming to facilitate a 19.5% net emissions reduction (2019–2025). The 2030 plan comprises 93 measures spanning mitigation, adaptation, research, and social dimensions, demonstrating comprehensive sectoral integration. The ambition of its GHG emissions reduction targets strongly increased from 24.6% (2019) to 75% (2025) by 2030, with carbon neutrality advancing from 2050 to 2040.
United Kingdom
Founding Member
Wales’ Well-being of Future Generations Act of 2015 garnered international recognition. However, Wales enacted fewer climate policies than other UK devolved administrations due to constitutional entanglement with English law and its limited devolved competencies, which cover only about 30% of Welsh emissions.
The Welsh approach prioritized waste management excellence, achieving 98 percent municipal waste diversion from landfill by 2022, and its housing efficiency standards addressed some of Europe’s oldest and least efficient building stock. Policy instruments targeted energy efficiency measures through Buildings and Housing Quality standards, subsidies, and circular economy initiatives including early carrier bag charging.
Post-U2C founding, Wales leveraged available powers effectively while using coalition membership to amplify limited structural authority. The 2016 Environment Act established binding GHG emissions reduction targets (45% by 2030, 67% by 2040, 80% by 2050) with five-year carbon budgets, demonstrating sustained ambition within constitutional constraints.
Target evolution reflected an early comprehensive approach, with 2010 commitments encompassing all Welsh emissions (40% reduction by 2020). Post-2021 targets became more ambitious (63% by 2030, 89% by 2040, net-zero by 2050) following Climate Change Committee advice.
Early Joiner
Scotland demonstrated the strongest UK climate ambition despite only being an early adopter, using U2C membership to reinforce independence aspirations and exceed national-level commitments. Scotland’s climate leadership predated U2C membership through the landmark 2009 Climate Change Act, which exceeded the 2008 UK Act in stated ambition thanks to comprehensive annual net-zero targets (2010–2022).
The number of climate policies adopted exceeded that of all other UK jurisdictions, with Scotland adopting comprehensive planning frameworks and just transition mechanisms. The Climate Challenge Fund (2008–2022) supported community-scale decarbonization, while flagship initiatives included the world’s first Climate Justice Fund (2012), a Just Transition Commission (2018), and Loss and Damage financing commitments as COP 26 host nation.
Scotland’s policy instruments showed innovation and large-scale ambition early. However, implementation challenges emerged, leading the Climate Change Committee to describe Scotland’s 2030 goals as lacking credibility. As a consequence, Scotland had to scale back its interim targets, emulating UK and Welsh approaches. Nonetheless, it retained a headline net-zero by 2045 commitment.
Later Joiners
Northern Ireland exhibited delayed policy-based climate action, which is attributable to post-conflict recovery priorities and repeated Assembly suspensions totaling one-third of its existence since 1998. However, its 2021 U2C accession coincided with a remarkable increase in climate policy effort through “New Decade, New Approach” commitments that align with Paris Agreement objectives. The landmark 2022 Climate Change Act legislated net-zero by 2050, an 82% reduction by 2050, and carbon budgets spanning three periods (2023–2037) with 33–62% average annual reductions. Northern Ireland’s policy instruments remained limited but targeted.
Isle of Man’s climate action accelerated following its U2C accession in 2021. Early policy development commenced in 2006 with its recognition of energy challenges, which evolved through a renewable energy potential assessment (2010), strategic frameworks (2013–2016), and comprehensive planning (2020). The 2021 Climate Change Act, adopted shortly after U2C membership, legislated net-zero by 2050 with five-year action plans following the UK model. The Isle of Man’s policy instruments focused on financing and regulatory approaches, encompassing a Sustainable Financing Framework (2018), an Energy Efficiency Scheme (2018), a Green Living Grant Scheme (2021), and innovative measures including bans on single-use plastics (2023), bottom trawling restrictions (2024), and fossil-fuel heating prohibitions for new buildings (2025). The evolution of its GHG emissions reduction targets was marked by increasing ambition. A first long-term target of 80% GHG emissions reduction by 2050 set in 2013 was replaced by a net-zero emissions target by 2050 in 2021. Intermediate targets of 35% GHG emissions reduction by 2030 and 45% by 2035 complement the Isle of Man’s long-term strategy since 2022.
Cross-Regional Patterns and Insights
The analysis confirms that founding and early members of U2C generally demonstrate more climate policy effort, but these incentives interact in complex ways with domestic factors that shape their climate policy trajectories.
Rather than initiating new climate commitments, U2C membership typically reinforced existing climate policy trajectories among member jurisdictions. This pattern is evident in the cases of Baden-Württemberg, British Columbia, and Catalonia, all of which had already established substantial climate policy frameworks before joining the coalition. This suggests that U2C membership serves more as a platform for amplifying pre-existing commitments than as a catalyst for initial climate action.
However, sustained climate leadership requires institutional stability, which proves vulnerable to changes in the political setting in which policymaking takes place. This challenge is particularly evident in the cases of Ontario and North Rhine-Westphalia, where rapid policy reversals and reduced ambition following electoral transitions highlight the fragility of climate commitments in the face of changing political landscapes.
The capacity for sustained leadership is also significantly influenced by geographic and economic factors unique to each jurisdiction. Scotland’s substantial renewable energy potential, Baden-Württemberg’s strong technological base, and California’s extensive regulatory authority all facilitated their ability to maintain climate leadership over time. These inherent advantages provide a foundation for ambitious climate policies that transcends political cycles.
Beyond these governance dynamics, clear evidence emerges of policy diffusion through U2C networks, demonstrating the coalition’s role as a conduit for knowledge transfer. California’s vehicle emission standards exemplify direct policy transfer, with multiple states subsequently adopting these regulations, even across national boundaries. Similarly, Scotland’s Climate Justice Fund has influenced the prioritization of comparable climate justice initiatives in Wales and other UK jurisdictions. Furthermore, later adopters frequently reference existing climate laws from other U2C members when developing their own legal frameworks, creating a pattern of institutional emulation across the network.
This interconnected web of policy learning and adaptation illustrates how U2C functions not merely as a symbolic commitment platform, but as an active mechanism for the diffusion of climate governance innovations across subnational jurisdictions. Global participation patterns of U2C signatories demonstrate that the platform has helped not only founding and early joiners sustain climate action, but also to lead by encouraging other states and regions to join the network and implement ambitious polices, instruments, and targets.
Temporal Patterns and Membership Dynamics
The founding members generally exhibited climate frameworks predating U2C establishment, suggesting the coalition emerged from existing leadership. California’s trajectory epitomizes this pattern: its Global Warming Solutions Act of 2006 established comprehensive GHG emissions reduction targets and regulatory architecture nearly a decade before U2C formation. The state’s subsequent climate policies, including cap-and-trade implementation and successive scoping plans, built on this foundation rather than on U2C membership.
Baden-Württemberg similarly demonstrated early leadership with Germany’s first renewable heat mandate for existing buildings in 2008 and a comprehensive climate protection law in 2013. The state’s post-2015 activities—revised legislation, sectoral strategies, and expanded policy instruments—represent continuation and deepening of existing trajectories rather than new directions prompted by U2C participation.
However, founding membership provides no guarantee of sustained leadership. Ontario’s experience is particularly instructive: despite cofounding U2C and implementing an ambitious cap-and-trade program linked with California and Québec, the 2018 election brought a Progressive Conservative government that swiftly dismantled climate policies, withdrew from carbon pricing, and canceled renewable energy projects. This reversal, despite the reputational costs of abandoning a flagship U2C initiative, illustrates how domestic political dynamics can overwhelm international commitments.
Early adopters, joining July 2015–2016, exhibit remarkably varied trajectories that complicate simple categorization. Scotland—technically an early adopter, having joined two months after founding—demonstrates leadership exceeding that of many founding members. Its role as European co-chair, its pioneering of climate justice initiatives—including the world’s first Climate Justice Fund—and its ambitious targets (net-zero by 2045, five years ahead of the UK) position it as a de facto climate leader.
Massachusetts and New York leveraged early membership to amplify existing policy frameworks while developing new initiatives. Both states built on their RGGI participation to develop comprehensive legislation— Massachusetts’ Next-Generation Roadmap (2021) and New York’s Climate Leadership and Community Protection Act (2019)—that established some of the United States’ most ambitious subnational targets. Their post-2015 acceleration of climate action suggests U2C membership provided legitimacy and learning opportunities that facilitated policy expansion.
Conversely, several early joiners demonstrate persistently low levels of climate policy effort. New Hampshire adopted minimal policies and lacks binding targets despite joining in 2015. Minnesota experienced a decadelong plateau (2008–2018) with little progress. Bavaria, despite early U2C membership and favorable conditions following nuclear phase-out, remains a climate laggard among German states. These cases suggest that membership timing alone does not determine ambition levels.
Later entrants, joining 2017–2024, present the most diverse patterns, challenging assumptions that late adoption indicates lower ambition. Some jurisdictions, like Rhineland-Palatinate, had established comprehensive frameworks before joining—its 2014 Climate Protection Act preceded membership by three years—suggesting strategic timing rather than followership. The state used U2C primarily for international visibility and legitimacy rather than policy learning.
Galicia exemplifies entrepreneurial use of late membership, deliberately timing its November 2021 accession to coincide with COP 26 for maximum visibility. The conjunction of international attention and domestic momentum created policy windows that earlier membership might not have provided.
Other late entrants display clearer patterns of followership. Northern Ireland’s 2021 accession followed decades of climate policy neglect— attributable to post-conflict priorities and institutional instability. Its subsequent Climate Change Act (2022) closely emulates Scottish and Welsh approaches, suggesting followership. The Northwest Territories similarly used 2017 membership to import southern Canadian approaches while adapting them to Arctic contexts.
Conclusion
This analysis reveals that while U2C membership timing influences climate policy effort, the relationship is mediated by complex domestic factors that often prove more decisive than coalition entry sequencing. Founding members generally demonstrate sustained leadership trajectories, establishing comprehensive policy frameworks and maintaining climate action through political transitions. However, some early joiners match or exceed their performance through strategic leveraging of existing institutional capacity and favorable political contexts, while certain later adopters show remarkable acceleration that challenges simple assumptions about first-mover advantages.
Evidence suggests U2C functions primarily as an amplifying mechanism rather than as a transformative catalyst, reinforcing existing climate policy trajectories and providing reputational incentives for sustained action. The coalition appears most effective when subnational governments already possess foundational climate commitments, institutional capacity, and political will. In these contexts, U2C membership offers external validation, policy learning networks, and international visibility that strengthen domestic climate governance. Conversely, U2C membership alone proves insufficient to overcome weak political commitment or institutional constraints, as demonstrated by the laggard performance of some early joiners.
In short, domestic political contexts, institutional capacity, and structural factors remain decisive in determining actual policy outcomes. States and regions with robust institutional frameworks, cross-party consensus, and effective framing of economic co-benefits exhibit greater policy durability. Constitutional arrangements also significantly influence outcomes. Federal systems—such as those in Canada, Germany, and the United
States—enable more autonomous climate action than quasi-federal systems like Spain or more centralized systems like the UK. Nevertheless, intra-country variations suggest that local political factors often override these structural constraints.
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CHAPTER 9	
Conclusion
Abstract This concluding chapter synthesizes findings from comparative analysis of subnational governments across the United States, Canada, Germany, Spain, and the UK to assess whether Under2 Coalition founding members demonstrate greater climate leadership than later joiners. The analysis reveals mixed support for propositions linking reputational incentives to climate policy effort: California, Baden-Württemberg, and Catalonia exhibited sustained leadership consistent with theoretical expectations, while cases like Ontario and Scotland complicate straightforward temporal patterns. Beyond membership timing, constitutional arrangements, partisan composition, economic context, and institutional capacity emerge as critical mediating factors. The study identifies four leadership types—structural, cognitive, entrepreneurial, and exemplary—manifested across jurisdictions, while recognizing followership as strategically significant, with some actors using it as a calculated pathway toward eventual leadership. Key limitations include conceptual simplification of leader- ship/followership dynamics, exclusive focus on high-income democracies, and case selection biased toward Under2 Coalition members. The chapter alludes to future research which could expand geographic scope to Latin America and other regions, develop more nuanced theoretical frameworks integrating multilevel governance and network effects, and incorporate non-member jurisdictions for comprehensive comparison.

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© The Author(s) 2026
J. Tosun et al., Subnational Climate Leadership Dynamics Among Under2 Coalition Members, Palgrave Studies in Sub-National
Governance, https://doi.org/10.1007/978-3-032-12610-8_9
Keywords Climate followership • Climate leadership • Constitutional arrangements • Subnational leadership dynamics • Transnational climate networks
Introduction
The proliferation of transnational networks connecting subnational governments represents a noteworthy development in contemporary climate governance (Bäckstrand et al., 2017; Francesco et al., 2020; Heikkinen et al., 2019; Tosun et al., 2023; Unger & Thielges, 2021). These networks enable knowledge sharing, peer learning, and collective action among jurisdictions that might otherwise operate in isolation (Boyd, 2017).
This book investigated the U2C and sought out to examine whether founding members of U2C demonstrate greater climate leadership and policy effort compared to subnational governments that joined the coalition later. Through detailed case studies we assessed climate policy effort across multiple dimensions and over time. Our research design specifically addressed the temporal dimension of climate policy effort, recognizing that leadership manifests itself not only in early policy adoption but also in maintaining ambitious policies despite changing economic, social, and political contexts. In this concluding chapter, we are now positioned to provide answers to our central research questions.
Main Findings
Assessment of the Propositions
Our first proposition formulated in Chap. 2 argued that reputational incentives are linked to levels of climate policy effort, influencing both the scope of activity and level of ambition. We further argued that U2C founding members should be particularly susceptible to reputational costs if they lower their climate policy effort. This effect should be present for early joiners but less so for later joiners. The second proposition rests on the same argument but applies it to the temporal stability of climate policy effort over time: reputational incentives should help to maintain the level of climate policy effort by founding members and—though possibly to a lesser extent—by governments that joined U2C later.
For the United States, California’s policy development fully aligns with both propositions, though the empirical picture is more mixed for the other U2C founding members and for early joiners in the United States. Even so, the US data showed that later joiners demonstrate less policy effort than founding members and early joiners.
The findings for Canada revealed that U2C founding members maintained and enhanced their subnational climate policy effort—with the exception of Ontario. This reversal, despite the reputational costs of abandoning a flagship U2C initiative, illustrates how domestic political dynamics can overwhelm international commitments.
In Germany, Baden-Württemberg, as a founding member, has also been more eager to show sustained climate policy effort than the other states, whereas Bavaria and Thuringia have exhibited less climate policy effort despite being early joiners.
Broader support for the proposition was observed for the subnational governments in Spain, with Catalonia demonstrating particularly high climate policy ambition. This observation is even more remarkable considering that Catalonia’s Law 16/2017 on Climate Change was partially struck down by the Constitutional Court in 2019 due to ambiguities in the constitutional rights of the autonomous communities in Spain. This forced the Catalonian government to pursue climate objectives through decree laws and alternative mechanisms.
The UK emerged as a noteworthy case since Scotland, an early joiner, consistently demonstrated higher climate policy effort than Wales, a founding member. An important element in explaining this is the UK’s constitutional asymmetry, which creates distinct challenges and opportunities across its constituent nations. Scotland’s greater autonomy, secured through successive devolution settlements, enables climate policy exceeding UK ambitions, whereas Wales remains deeply entangled with English policy (Royles & McEwen, 2015).
The chapters on Canada, Spain, and the UK explicitly examined whether the climate policy effort made by the subnational entities could be attributed to their U2C membership. While we cannot establish a causal connection, it is worth noting that Northern Ireland and the Isle of Man, two later joiners, increased their climate policy effort following their entry into the coalition, indicating that U2C participation may serve as one contributing factor among many in driving enhanced climate action at the subnational level. On the other hand, the U2C membership of Andalusia happened at a point in time when it already had a high level of climate policy effort, suggesting that membership is not the driving force behind its climate policy effort.
Overall, the empirical insights support the proposition that U2C membership influences climate policy effort over time, but they also revealed that we must pay attention to several additional factors. One of these fac- tors—as already discussed above—refers to the constitutional setup in the countries where subnational governments operate, which defines the formal opportunity structure for their climate policy efforts.
The analyses of subnational governments in Canada, Germany, and the United States elucidated the importance of the regional government’s ideological composition. In Canada, Ontario’s cap-and-trade program was repealed following a change in partisan control, where the Progressive Conservative Party replaced the Liberal Party in government. In Germany, states with Green Party participation in government consistently demonstrate higher climate policy effort. Baden-Württemberg’s sustained leadership under Green Party Prime Minister Winfried Kretschmann exemplifies this pattern and contrasts sharply with Bavaria’s persistent lagging despite having favorable structural conditions for climate action. Notably, Bavaria’s weaker performance coincides with the fact that the Green Party has never participated in its state government, reinforcing the importance of ideological composition in driving ambitious climate policies.
However, partisan composition is not the only way how political parties and their ideologies matter. The case of Oregon demonstrates that constitutional requirements for policymaking can also constrain political parties’ power. Ambitious climate policy bills failed despite Democrats holding majorities in both the Oregon State Senate and House of Representatives, as Republicans exploited a two-thirds quorum requirement to block legislation.
Furthermore, several chapters illustrated the importance of economic context for climate policy effort and how it has evolved over time. North Rhine-Westphalia’s heavy reliance on coal, despite its early U2C leadership, limited its policy options and constrained stakeholder support for ambitious climate action. Conversely, the analysis showed that jurisdictions with “cleaner” economic structures faced fewer barriers to policy implementation. For instance, service-dominated economies like Madrid and renewable-disposed regions like Québec encountered less economic resistance to higher climate policy effort. This structural variation suggests that effective climate governance requires differentiated approaches that account for local economic contexts rather than ones which pursue uniform ambition levels across jurisdictions.
The assessment of Spain broadened the analytic perspective by highlighting the critical importance of policy implementation, revealing that some subnational governments exhibit high effort in policy formulation but fall short in execution due to insufficient institutional capacity. More precisely, the Foral Community of Navarre’s small administrative apparatus illustrates how size limitations can constrain implementation regardless of political will. The chapter on Spain was not the only one to address constraints in institutional capacity. For instance, the Isle of Man depends heavily on external consultants, while the Northwest Territories in Canada lack technical expertise. Northern Ireland’s unique post-conflict governance arrangements, which include power-sharing requirements and periodic assembly suspensions, create additional implementation challenges that are absent in other UK nations.
Types of Climate Leadership
The chapters offered valuable insights into different types of climate leadership as defined by Wurzel et al. (2019). Structural leadership emerges most clearly in jurisdictions combining constitutional authority, economic resources, and natural advantages. California’s unique CAA waiver exemplifies how constitutional arrangements can enable subnational leadership—no other state possesses this authority to set vehicle emission standards, yet all states can choose to adopt California’s. These elements form the bedrock of California’s structural leadership.
Cognitive leadership through reframing climate action proves particularly powerful in overcoming structural disadvantages. For example, both the Basque Country and Galicia successfully reframed climate policy as economic modernization essential for regional competitiveness and the creation of jobs. This cognitive reframing aligned climate action with regional development priorities, generating broader political support for it.
Entrepreneurial leadership depends on effective coalition building and strategic positioning, which the governments of Québec and California demonstrated when establishing the joint cap-and-trade system in 2014. This innovative arrangement enables the mutual recognition and trading of emissions allowances between the two jurisdictions to address GHG emissions. Galicia exemplifies entrepreneurial use of late membership, deliberately timing its November 2021 accession to coincide with COP26 for maximum visibility. This strategic approach facilitated rapid and comprehensive domestic reform of its GHG emissions reduction targets. The conjunction of international attention and domestic momentum created climate policy windows that earlier membership might not have provided.
Exemplary leadership through policy innovation creates templates for replication across jurisdictions. Connecticut’s green bank model, established in 2011, has been replicated across numerous US states and U2C members, as has Hawaii’s 100% renewable electricity target, which was initially dismissed as unrealistic. Another example is Scotland’s Climate Justice Fund, which provided a model for integrating equity concerns into climate finance.

This information is taken from the following website: https://www.cesa.org/ projects/100-clean-energy-collaborative/guide/table-of-100-clean-energy-states/ and https://www.theclimategroup.org/under2-coalition/region/victoria (last access 11 September 2025).

Followership
The empirical analysis revealed that followership is a relevant phenomenon even for U2C members. In this context, our analysis has provided two important insights. First, some subnational governments join U2C to be better able to follow the policy effort of climate leaders. Our analyses did not identify these entities as having the ambition to become leaders within their respective country or the U2C context. Northern Ireland’s 2021 accession followed a decades-long dearth of subnational climate policy, which we can attribute to post-conflict priorities and institutional instability. Its subsequent Climate Change Act (2022) closely emulates Scottish and Welsh approaches, suggesting membership facilitated policy transfer. However, the Climate Change Act does not exceed the level of policy effort demonstrated by Scotland and Wales. The Northwest Territories in Canada similarly used 2017 membership to import southern Canadian approaches while adapting them to Arctic contexts.
Second, some subnational governments strategically positioned themselves as followers initially in order to emerge later as leaders, with Vermont in the United States serving as a compelling example. Initially, Vermont’s government deliberately followed California’s established leadership by adopting and adapting its proven climate policies. This strategic mimicry allowed Vermont to build institutional capacity and policy expertise while avoiding the costs and risks associated with pioneering untested approaches. Eventually, this foundation put Vermont in a strong position to act as a climate leader in its own right, particularly within the context of another transnational collaborative framework: the NEG-ECP. This trajectory suggests that strategic followership can serve as a calculated pathway to leadership, where subnational actors leverage the experiences of pioneers to develop their own capacity for innovation and regional influence.
Our observations regarding the relevance of followership suggest that engaging more profoundly with this group of subnational governments would allow us to acquire a better understanding of climate leadership, which aligns with the main conclusion in the pertinent literature (Tobin et al., 2023; Torney, 2019; Underdal, 1998; Wurzel et al., 2019).
Limitations
We acknowledge that this study, while providing valuable insights into subnational climate leadership dynamics within U2C, operated within certain analytic constraints that have inevitably shaped our findings and conclusions. For one, the analysis’ conceptual engagement with leadership was limited. As explained in Chap. 2, we simply assumed that subnational governments strive to act as leaders, but did not actually test this. Furthermore, we assessed the different types of leadership according to the relevant literature; however, leadership as a concept requires more comprehensive engagement and critical reflection. Even more importantly, although we engaged with followership in the country chapters, we did not theorize its complex relationship with leadership. Consequently, more theorizing is needed to better understand the dynamic relationship between leaders and followers, as well as which factors shape the transition from leader to follower and vice versa (see Torney, 2019).
Moreover, we acknowledge that our analysis does not cover the full range of U2C members and their diverse contexts. Most importantly in this regard, this book focuses exclusively on high-income democracies; we therefore cannot draw meaningful conclusions for subnational units operating in less affluent countries and/or countries that are anocracies or even autocracies, which are substantively represented within the U2C membership. For instance, several subnational entities in Latin American countries partake in U2C and other transnational climate governance initiatives (Tosun et al., 2023). This geographic and political-economic limitation significantly constrains the generalizability of our findings and highlights the need for expanded comparative research that encompasses the full spectrum of U2C participants across different developmental and governance contexts.
However, rather than viewing these limitations as shortcomings, we recognize them as productive starting points for future research endeavors that could substantially enhance our understanding of subnational climate policy across three interconnected dimensions: conceptual, theoretical, and empirical.
Future Research Directions
Our conceptual framework, while grounded in established scholarship on climate leadership and followership, reveals several areas where future research could refine and expand our understanding of leadership and followership in the context of subnational climate governance. First, our conceptualization of climate leadership focused primarily on policy outputs, target-setting, and temporal sequences of action, but future studies could develop more nuanced conceptualizations that incorporate qualitative dimensions of leadership, such as policy innovation as well as the strategies leaders adopt for advocacy and to influence other jurisdictions. Additionally, our distinction between founding members, early joiners, and later joiners represents a necessary simplification for a comparative analysis that accounts for timing, but future research could explore more sophisticated categorizations that take into account the motives determining the decision over whether and when to join climate governance coalitions.
The concept of followership also deserves greater conceptual attention, as our analysis suggests that later joiners may exhibit different forms of climate commitment that do not necessarily represent inferior performance but rather alternative pathways to climate policy effort. In this regard, it was interesting to observe that some of the later joiners initially followed leaders with the ultimate aim of becoming leaders themselves—a dynamic for which we did not account in our conceptual framework.
From a theoretical perspective, our reliance on leadership, while productive, represents only one lens through which to understand the climate policy effort made by subnational governments within transnational networks. Future theoretical development could integrate auxiliary mechanisms to better explain how transnational networks like U2C shape members’ behavior at a particular point in time as well as over time. The empirical chapters have shown that economic, social, and political factors need to be considered alongside the constitutional foundation of countries and how much leeway they leave subnational governments to embrace climate policy and exceed what is defined at the central level.
The multilevel governance literature offers another promising theoretical avenue for expanding our framework. Our analysis controlled for national-level variables but did not systematically theorize the complex interactions between local, regional, national, and transnational governance levels. However, all our case studies have suggested that this interaction is important for explaining the dynamics of climate policy effort at the subnational level. Future research could develop more sophisticated theoretical models that specify how these interactions shape subnational climate policy effort.
Network theory presents additional opportunities for theoretical advancement. While we examined U2C members’ performance, we did not systematically analyze network effects, peer influence, or the role of network position in shaping climate action. Future theoretical development could incorporate social network analysis to understand how relationships within and across transnational climate networks affect policy adoption, implementation, and effectiveness.
Our empirical analysis, while comprehensive within its defined scope, suggests several directions for future research that could significantly enhance our understanding of subnational climate policy effort. First, geographic expansion beyond our European and North American focus represents a crucial next step. As noted, jurisdictions like the Mexican states of Baja California and Jalisco, and the Brazilian state of Acre, offer important opportunities for examining climate leadership dynamics in Latin American contexts, where different political, economic, and institutional conditions may produce distinct patterns of subnational climate action (see, e.g., Tosun et al., 2023).
Geographical extension within the countries from which subnational units participate would also provide valuable empirical opportunities. We are aware that our case selection hinged on the dependent variable, that is, we only assessed subnational entities that participate in U2C. While this perspective has enhanced our understanding of the climate policy effort made by U2C-affiliated subnational governments, we cannot draw any conclusions for those that did not join the coalition. We consider it plausible that U2C members worldwide demonstrate higher levels of climate policy effort; however, our analysis lacks the scope to prove this.
Conclusion
Overall, our analysis revealed that U2C membership is often associated either with existing, high levels of climate policy effort or with increased effort after joining. However, in some instances, subnational governments also reduced their efforts after joining. This latter finding suggests that reputational incentives arising from U2C membership play a role, but they cannot overcome deliberate political action to scale back climate policy or economic or structural constraints (Patterson, 2023). California, Baden- Württemberg, Scotland, and Catalonia stood out in our analysis as U2C members with particularly high and sustained levels of climate policy effort. These jurisdictions share a similar combination of economic, social, and political factors that predisposes them to higher climate policy effort.
The varied outcomes challenge our initially deterministic narratives about climate leadership. Founding membership neither guarantees sustained leadership nor precludes later joiners from ambitious action. For instance, structural advantages like renewable resources or economic strength prove insufficient without political commitment. These findings underscore the importance of understanding subnational climate action as embedded within specific contexts rather than as responding uniformly to transnational dynamics (Dubash, 2021). Nonetheless, transnational collaboration and leveraging favorable domestic conditions also matter.
As climate governance increasingly depends on subnational implementation, these insights become crucial for developing more effective approaches to climate governance which accelerate GHG emissions reductions (Boasson et al., 2025). Rather than assuming uniform ambition or capability, effective multilevel strategies must account for the fact that constitutional variations, political dynamics, and economic structures all shape subnational action. The U2C and similar networks can facilitate learning and legitimacy but must also recognize their limitations in overcoming domestic constraints. Future climate governance architectures should therefore emphasize flexible, context-appropriate approaches that enable diverse pathways toward shared objectives while acknowledging the persistent challenges revealed by this comparative analysis.
References
Bäckstrand, K., Kuyper, J. W., Linnér, B.-O., & Lövbrand, E. (2017). Non-state actors in global climate governance: From Copenhagen to Paris and beyond. Environmental Politics, 26(4), 561–579.
Boasson, E. L., Peters, G. P., & Tosun, J. (2025). Policy-driven acceleration of climate action. PLOS Climate, 4(5), 1–12. https://doi.org/10.1371/journal. pclm.0000626
Boyd, B. (2017). Working together on climate change: Policy transfer and convergence in four Canadian provinces. Publius: The Journal of Federalism, 47(4), 546–571. https://doi.org/10.1093/publius/pjx033
Dubash, N. K. (2021). Varieties of climate governance: the emergence and functioning of climate institutions. Environmental Politics, 30(sup1), 1–25. https://doi.org/10.1080/09644016.2021.1979775
Francesco, F. D., Leopold, L., & Tosun, J. (2020). Distinguishing policy surveillance from policy tracking: Transnational municipal networks in climate and energy governance. Journal of Environmental Policy & Planning, 22(6), 857–869. https://doi.org/10.1080/1523908X.2020.1785280
Heikkinen, M., Ylä-Anttila, T., & Juhola, S. (2019). Incremental, reformistic or transformational: What kind of change do C40 cities advocate to deal with climate change? Journal of Environmental Policy & Planning, 21(1), 90–103. https://doi.org/10.1080/1523908X.2018.1473151
Patterson, J. J. (2023). Backlash to Climate Policy. Global Environmental Politics, 23(1), 68–90. https://doi.org/10.1162/glep_a_00684
Royles, E., & McEwen, N. (2015). Empowered for action? Capacities and constraints in sub-state government climate action in Scotland and Wales. Environmental Politics,	24(6),	1034–1054. https://doi.org/10.108 0/09644016.2015.1053726
Tobin, P., Torney, D., & Biedenkopf, K. (2023). EU climate leadership: Domestic and global dimensions. In T. Rayner, K. Szulecki, A. J. Jordan, & S. Oberthür (Eds.), Handbook on European Union climate change policy and politics (pp. 187–200). Edward Elgar Publishing. https://doi. org/10.4337/9781789906981.00025
Torney, D. (2019). Follow the leader? Conceptualising the relationship between leaders and followers in polycentric climate governance. Environmental Politics, 28(1), 167–186. https://doi.org/10.1080/09644016.2019.1522029
Tosun, J., Saad, E. L., Glückler, J., Irigoyen Rios, A., & Lehmann, R. (2023). Country-specific participation patterns in transnational governance initiatives on sustainability: Preliminary insights and research agenda. Global Challenges, 7(8), 2300012. https://doi.org/10.1002/gch2.202300012
Underdal, A. (1998). Leadership in international environmental negotiations: Designing feasible solutions. In A. Underdal (Ed.), The politics of international environmental management (Vol. 4, pp. 101–127). Springer Netherlands. https://doi.org/10.1007/978- 94- 011- 4946- 4_6
Unger, C., & Thielges, S. (2021). Preparing the playing field: Climate club governance of the G20, Climate and Clean Air Coalition, and Under2 Coalition. Climatic Change, 167(3–4), 41. https://doi.org/10.1007/ s10584- 021- 03189- 8 Wurzel, R. K. W., Liefferink, D., & Torney, D. (2019). Pioneers, leaders and followers in multilevel and polycentric climate governance. Environmental Politics, 28(1), 1–21. https://doi.org/10.1080/09644016.2019.1522033
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A
Australia
South Australia, 7

B
Brazil
Acre, 5, 7, 14, 183
Amazonas, 8
Mato Grosso, 7, 8
São Paulo, 7, 8
C
Canada
British Columbia, 5, 12, 72–73, 76–78, 81, 82, 84–87, 163, 170
Northwest Territories, 8, 12, 72, 75–77, 80, 81, 83–85, 87, 88, 164, 173, 179, 180

Ontario, 5, 12, 72–74, 76–79, 82, 84–87, 163, 170, 171,
177, 178
Québec, 7, 12, 72, 74–77, 79–81, 83–87, 163, 171, 178, 179
Capacity, 9, 28–30, 41, 45, 47, 65, 75, 86, 117, 119, 120, 124, 130–133, 139, 140, 142, 144, 150, 153, 154, 160, 161, 170, 173, 179, 180
China
Jiangsu, 7
Sichuan, 7
Climate framework law, 39, 99–102, 104, 116, 117, 119, 122, 126, 127, 164–166, 171, 172
Climate Group's States & Regions Alliance (CGSRA), 6
Climate Pathway Project
(CPP), 8

1		Note: Page numbers followed by ‘n’ refer to notes.
© The Editor(s) (if applicable) and The Author(s), under exclusive	187
license to Springer Nature Switzerland AG 2026
J. Tosun et al., Subnational Climate Leadership Dynamics Among
Under2 Coalition Members, Palgrave Studies in Sub-National
Governance, https://doi.org/10.1007/978-3-032-12610-8
E
Economic pressure, 27, 30, 110–112, 178
Electoral cycle, 26, 95, 118, 163, 170
European Union (EU), 13
F
Followership, 10, 11, 13, 24, 40, 41, 65, 66, 87, 88, 110, 111, 138, 150, 152–154, 162, 172,
173, 180–182
France
Aquitaine, 7
Brittany, 7
Occitanie, 7
Poitou-Charentes, 7
Rhône-Alpes, 6, 7
G
Germany
Baden-Württemberg, 4, 4n1, 6, 7, 9, 12, 94–111, 164, 166, 170, 171, 177, 178, 184
Bavaria, 7, 94–97, 99–102, 105–110, 112, 165, 172, 177, 178
Hesse, 7, 94, 96, 97, 99–102, 105–110, 165
Lower Saxony, 94, 97, 102–104, 107–109, 111, 112, 165
North Rhine-Westphalia, 7, 96, 99–102, 105–107, 165, 170, 178
Rhineland-Palatinate, 94, 97, 102–104, 107–109, 111, 112, 166, 172
Schleswig-Holstein, 7, 94, 96,	97, 99–102, 105–110, 112, 165
Thuringia, 7, 94, 96, 97, 99–102, 105–107, 109, 110, 112, 165, 177
Governors' Climate & Forests Task Force (GCF), 5, 7
Greenhouse gas (GHG) targets long-term, 40, 44, 45, 48, 62–65, 74, 84, 85, 101, 102, 108, 109, 117, 123, 128, 129, 133, 139, 149, 150, 152, 162–167, 170 medium-term, 62, 84, 102, 109, 128, 129, 131, 149, 150, 162, 163, 165, 166 net-zero, 44, 46, 50–53, 56, 64, 85, 100, 103, 104, 129–131, 144, 145, 150–152, 161–163, 166–170, 172 short-term, 62, 84, 85, 108, 128, 129, 149, 150, 166
Green party, 27, 95, 97, 103, 104, 109–112, 178
I
Italy
Emilia-Romagna, 7
Lombardy, 7
Piedmont, 7
Sardinia, 7
J
Japan
Gifu, 7
L
Leadership, 3, 10–14, 20, 23–31
cognitive, 24, 25, 28, 31, 41, 43, 45, 49–54, 65, 86, 87,
109–111, 122–125, 130, 131, 133, 138, 152, 179 entrepreneurial, 25, 28, 31, 44, 65, 86,	109, 122–125, 130–133, 138, 139, 153, 172, 179 exemplary, 25, 28, 31, 42, 44, 45, 48–50, 54, 65, 109–111, 123–125, 130–133, 138, 153,	180 structural, 25, 28, 31, 48, 65, 86, 109, 110, 125, 138, 179
M
Mexico
Baja California, 5, 14, 183
Jalisco, 5, 14, 183
Madre de Dios, 8
Mexico State, 7
Querétaro, 8
Quintana Roo, 8
Multilevel governance (MLG), 20–23
Morocco, 7
Multilevel, 2, 10, 11, 14, 20, 22, 28,
31,		38, 72, 94, 116, 123, 129,
183, 184
N
Nepal
Kathmandu Valley, 7
Netherlands
Drenthe, 7
Network of Regional Governments for
Sustainable Development
(NRG4SD), 6, 123
P
Pacific Coast Collaborative (PCC), 5
Peru
Ucayali, 7
Pioneer, 23, 24, 181
Policy backlash, 28, 86, 170, 172
Policy diffusion, 161, 171
Policy effort, 2, 4, 10–13, 20, 23,
29–31, 66, 160, 165, 169, 170, 172, 173, 176–178,
180,		182–184
Policy instruments
ban, 58, 61, 82, 125, 127, 149 cap-and-trade, 38–40, 43, 58–60, 63,	73, 74, 78, 82–84, 86, 88, 161, 163, 171, 178, 179 certification, 58, 126, 127, 167 information, 58, 59, 84, 104, 106–108, 125, 126, 148, 161, 164 public procurement, 58, 59,	125–127 standard, 39–42, 44, 46, 48–50, 53, 58, 59, 84, 101, 104, 107, 125–127, 145, 147, 161, 162, 165, 167, 168, 171, 179 subsidy, 58, 59, 73, 74, 78, 82, 86, 104, 106, 127, 146, 161, 165, 167, 168 tax, 58, 59, 61, 72, 82, 84, 86, 104, 125, 126, 163, 164, 172 voluntary agreement, 58, 84, 104, 126, 127, 131, 167
Political transition, 27, 109, 111, 112, 173
Polycentric, 22, 31, 38
Portugal
Azores, 7
Madeira, 7
Proposition, 21, 28–31, 66, 76, 111, 133, 154, 176–178
Public opinion, 26
R
Regional Greenhouse Gas Initiative (RGGI), 5, 7, 38, 43, 44, 46–48, 50, 51, 53, 56, 59, 60, 63, 65, 66, 161
Reputation, 29–31, 66, 76, 86–88, 133, 150, 154, 172, 173, 176, 177, 184
S
Spain
Andalusia, 12, 116, 119, 122, 124, 126, 127, 129–133, 167 Basque Country, 7, 12, 116, 118, 119, 121–123, 126–129, 131–133, 166, 179
Catalonia, 5–7, 12, 116–119, 121–123, 125–133, 166, 170, 177, 184
Galicia, 12, 116, 120–122, 125–130, 132, 133, 168, 172, 179 Madrid, 12, 116, 117, 120, 122, 124, 125, 127–130, 132, 133, 167, 178
Navarre, 7, 12, 116, 118–119, 121–128, 130–133, 167, 179
Sweden
Härjedalen, 7
Jämtland, 7
T
Technological development, 26
U
United Nations (UN), 2, 142, 152
Conference of Parties (COP), 3, 125, 132, 133, 147, 168, 169, 172, 179
Paris Agreement, 3, 9n2, 10, 75, 80, 83, 123, 131, 142, 144, 145, 169
UNFCCC (Framework Convention on Climate Change), 2, 3, 9n2
United Kingdom
Isle of Man, 8, 12, 138, 141–143, 145, 148–150, 152–154, 169, 177, 179
Northern Ireland, 8, 12, 138, 141–145, 147–154, 169, 173, 177
Scotland, 12, 138, 140, 142–144, 147–151, 153, 154, 169–172, 177, 180, 184
Wales, 5, 12, 138, 139, 142–146, 148–154, 168, 171, 177, 180
United States
California, 4–7, 12, 38–44, 39n1, 46, 48–55, 58, 62, 65, 66, 160, 161, 163, 170, 171, 176, 179, 180, 184
Colorado, 49, 56, 58, 59, 64–66, 162
Connecticut, 7, 43–44, 56, 59, 63, 66, 161, 180
Hawaii, 50, 56, 58–60, 62, 64–66, 162
Maine, 50–51, 56, 58–60, 62, 64–66, 162
Maryland, 51–52, 56, 58, 60–62, 64, 66, 162
Massachusetts, 7, 44–45, 55, 56, 59, 63, 65, 66, 161, 162, 172
Minnesota, 7, 45–46, 56, 59, 63, 65, 66, 161, 172
Nevada, 52, 56, 58–60, 64, 66, 162 New Hampshire, 7, 46–47, 56, 59, 63, 65, 66, 161, 162, 172 New Jersey, 52–53, 56, 58, 60, 62, 64, 162
New York State, 7, 47–48, 55, 59, 63, 65, 66, 161, 162, 172 Oregon, 5, 12, 38, 40–41, 55, 59, 62,	65, 66, 160, 178
Rhode Island, 7, 48–49, 56, 59, 63,	66, 161
Vermont, 5, 12, 41–42, 55, 59, 62, 66,	160, 180
Virginia, 53–54, 56, 58–61, 64, 66, 162
Washington, 5, 12, 38, 42–43, 54, 55, 59, 63, 65, 66, 160
W
Western Climate Initiative (WCI), 5, 7

Fig. 3.9 Greenhouse gas emissions reduction targets by later-joining signatories

Fig. 3.8 Greenhouse gas emissions reduction targets by early-joining signatories