June 19, 2025 - Today, the United States’ top subnational climate action coalitions – America Is All In, the U.S. Climate Alliance, C40 Cities, and Climate Mayors – announced a joint delegation of prominent leaders from across the country that will attend major climate events in the weeks ahead and share the critical progress local communities are delivering to advance ambitious climate goals.

At a moment when the U.S. federal government is stepping back from leadership on climate action, this diverse coalition of cities, states, corporations and academic institutions, is stepping up to reaffirm America’s sustained commitment to working with the global community to achieve the goals of the Paris Agreement at a series of events and meetings, including the UNFCCC June Climate Meetings in Bonn (June 16-26), London Climate Action Week (June 21-29), and a Paris Agreement 10-year anniversary event on June 23. Delegation members include:

• Mayor Kate Gallego, Climate Mayors Chair, C40 Steering Committee and Phoenix Mayor
• Secretary Yana Garcia, California Environmental Protection Agency
• Secretary Serena McIlwain, Maryland Department of the Environment
• Elizabeth Lien, Program Director for America Is All In
• Kate Wright, Executive Director, Climate Mayors
• Nathan Hultman, Director of the Center for Global Sustainability 
• Laura Tierney, Vice President of International Programs, Business Council for Sustainable Energy

"Cities like Phoenix are on the frontlines of climate change, and mayors have a unique responsibility—and opportunity—to drive meaningful solutions. Our actions at the local level not only protect our communities but also set the pace for global progress,” said Mayor Kate Gallego, Climate Mayors Chair, C40 Steering Committee and Phoenix Mayor. “By partnering with other local leaders around the world, we can exchange ideas, scale innovations, and build a united front for meaningful action. Together, we can turn bold commitments into tangible results and ensure a prosperous, sustainable future for generations to come."

“As the impacts of climate change grow more urgent, resolute climate action at the state and local level has never been more critical. California’s climate policies demonstrate that bold innovation can drive environmental progress and economic growth. Under Governor Newsom's leadership, California has added approximately 7,000 megawatts (MW) of new clean energy in 2024 alone; and greenhouse gas emissions in the state are down 20% since 2000, even as the state’s GDP increased 78% in that same period,” said Secretary Yana Garcia, California Environmental Protection Agency. “By advancing ambitious climate solutions and inspiring others to follow, California reaffirms its commitment to a sustainable future and to empowering a global movement for climate leadership where it matters most—on the ground, in our communities, and across industries.” 

"Maryland stands at the forefront of climate action, leading with innovation, resilience, and a steadfast commitment to protecting our environment for future generations. As we confront the challenges of a changing climate, collaboration is our greatest strength,” said Secretary Serena McIlwain, Maryland Department of the Environment. “By partnering with the international community, we can share solutions, amplify impact, and ensure a sustainable future that transcends borders. Together, we can build a greener, healthier, and more equitable world."

"Subnational action is the heartbeat of climate progress—it's where innovation meets implementation, and where bold commitments become real-world impact. At America Is All In, we see the power of cities, states, businesses, and communities coming together to drive change from the ground up. International climate events like these provide an unparalleled opportunity to amplify these efforts, foster collaboration across borders, and share solutions that can accelerate progress globally,” said Elizabeth Lien, America Is All In Program Director. “By working together, we can turn the tide on climate change and show the world that collective action is not only possible but unstoppable."

“American cities are feeling the impacts of climate change in real-time. Our mayors are taking action now to protect their communities while implementing forward-thinking solutions to reduce pollution at the source,” said Kate Wright, Executive Director of Climate Mayors. “Local leaders in the U.S. have demonstrated their unique ability to move further and faster on climate progress and remain steadfast in their commitment to build stronger communities and economies by confronting the climate crisis with ambition and imagination. Climate Mayors are ready to continue this progress and join forces with other local actors across the globe to create stronger cities where future generations can thrive.”

“Addressing the climate crisis requires action at every level, and subnational actors—cities, states, businesses, and communities—are critical drivers of meaningful change. Their leadership not only delivers impactful solutions locally but also builds momentum that inspires national and global action,” said Nathan Hultman, Director of the Center for Global Sustainability. “At this pivotal moment, it’s essential to continue advancing ambitious climate initiatives, leveraging research and innovation, and fostering collaboration to scale progress. By acting decisively at the subnational level, we can chart a path toward a more sustainable, resilient, and equitable future for all."

Secretary McIlwain and Director Nate Hultman will participate in roundtables, dialogues and workshops throughout the Bonn meetings. Secretary Mcllwain, Secretary Garcia, Mayor Gallego, Climate Mayors Executive Director Kate Wright, and All In Program Director Elizabeth Lien will represent the U.S. at London Climate Action Week, focusing on the conference’s impact goal of “whole of society” engagement. Secretary Garcia and Mayor Gallego will also attend Cities at the Forefront, the 10th anniversary celebration of the Paris Agreement, hosted by the City of Paris. 

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About America Is All In
America Is All In is the most expansive coalition of leaders ever assembled in support of climate action in the United States. Mobilizing thousands of U.S. cities, states, tribal nations, businesses, schools, and faith, health, and cultural institutions, the coalition is focused on developing and delivering an ambitious, all-in national climate strategy that meets the urgency of the climate crisis; scaling climate action around the country to accelerate the transition to a 100 percent clean energy economy; and promoting the leadership of non-federal actors on the world stage. America Is All In champions a whole-of-society mobilization to deliver the transformational change that science demands, with the goal of a healthy, prosperous, equitable, and sustainable future. To learn more or get involved, visit www.americaisallin.com and follow us on X, LinkedIn, Instagram, and Bluesky.

About Climate Mayors
Climate Mayors is a bipartisan network of nearly 350 mayors, demonstrating climate leadership through meaningful actions in their communities since 2014. Representing 46 states and nearly 60 million Americans, Climate Mayors reflects U.S. cities’ commitment to climate progress. For more information, visit our website and follow Climate Mayors on X, Bluesky, and LinkedIn.

About C40 
C40 Cities is a network of nearly 100 mayors of the world’s leading cities working to deliver the urgent action needed right now to confront the climate crisis and create a future where everyone, everywhere, can thrive. Mayors of C40 cities are committed to using a science-based and people-focused approach to limit global heating in line with the Paris Agreement and build healthy, equitable and resilient communities. We work alongside a broad coalition of representatives from labour, business, the youth climate movement and civil society to support mayors to halve emissions by 2030 and help phase out fossil use while increasing urban climate resilience and equity.

The current co-chairs of C40 are Mayor Sadiq Khan of London, United Kingdom, and Mayor Yvonne Aki-Sawyerr of Freetown, Sierra Leone; three-term Mayor of New York City Michael R. Bloomberg serves as President of the Board. C40’s work is made possible by our three strategic funders: Bloomberg Philanthropies, Children’s Investment Fund Foundation and Realdania.

To learn more about the work of C40 and our cities, please visit our website, or follow us on X/Twitter, Instagram, Facebook and LinkedIn.

About the U.S. Climate Alliance 
Launched on June 1, 2017 by the governors of Washington, New York, and California to help fill the void left by President Trump’s initial decision to withdraw the U.S. from the Paris Agreement, the Alliance has grown to include 24 governors from across the U.S. representing approximately 60% of the U.S. economy and 55% of the U.S. population. Governors in the Alliance have pledged to collectively reduce net greenhouse gas emissions by at least 26-28% by 2025, 50-52% by 2030, and 61-66% by 2035, all below 2005 levels, and collectively achieve overall net-zero greenhouse gas emissions as soon as practicable, and no later than 2050. 

The Alliance’s states and territories will continue to advance innovative and impactful climate solutions to grow the economy, create jobs, and protect public health, and have a long record of action and results. In fact, the Alliance reduced its collective net greenhouse gas emissions by 19% between 2005 and 2022, while increasing collective GDP by 30%, and is on track to meet its near-term climate goal by reducing collective GHG emissions 26% below 2005 levels by 2025. The coalition’s states and territories are employing more workers in the clean energy sector, achieving lower levels of dangerous air pollutants, and preparing more effectively for climate impacts and executing more pre-disaster planning than the rest of the country.