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Nathan Hultman

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Nate Hultman is the founder and director of the Center for Global Sustainability at the University of Maryland, and professor in the School of Public Policy. Hultman’s work focuses on developing, setting and achieving ambitious national climate goals, including nationally determined contributions under the Paris Agreement. This work includes diverse analytical and policy approaches to national climate strategies, including climate target setting, assessment, implementation and Nationally Determined Contributions (NDCs) under the Paris Agreement; U.S. NDCs and long-term net-zero strategy; international climate policy; the role of subnational actors to support national  and global climate action; U.S.-China bilateral climate engagement; non-CO2 greenhouse gas reductions; and national climate strategies in China, Indonesia, Brazil, India, Korea and others.

Hultman has served in government several times. From June 2024 to January 2025, he was distinguished senior advisor for climate ambition in the Office of the Special Presidential Envoy for Climate at the U.S. Department of State, where he contributed to the 2035 U.S. NDC, bilateral country engagements on NDCs and the COP29 Baku climate negotiations. Previously, from 2021-22, Hultman served as senior advisor in the Office of the Special rom June 2024 to January 2025, Hultman was on leave from the University of Maryland, serving as distinguished senior advisor for climate ambition in the Office of the Special Presidential Envoy for Climate at the U.S. Department of State, where he led the writing of the 2021 U.S. Long-Term Strategy and helped negotiate the U.S.-China Joint Glasgow Declaration at COP26. In the Obama White House, he helped develop the 2025 U.S. NDC and participated in the Lima and Paris climate negotiations.

Hultman has participated in the UN climate negotiations as a non-governmental observer for over 27 years, starting with the Kyoto meeting. He founded CGS in 2016 to support the cycle of ambition and action under the Paris Agreement and has supported its growth to a research organization of over 60 people. He has also been a nonresident senior fellow at the Brookings Institution in Washington, DC and a visiting fellow at the University of Oxford. He holds a B.A. in Physics from Carleton College and a Ph.D. in Energy & Resources from the University of California, Berkeley.

Areas of Interest
  • National climate strategies and NDCs under the Paris Agreement; energy policy and rapid transitions away from fossil fuels; international climate policy

Successfully addressing the climate crisis while achieving sustainable development goals will require carefully constructed strategies to enact rapid economic transitions to a cleaner economy—tailored to national circumstances and priorities. The Center for Global Sustainability has deep expertise in country-specific analytical and policy approaches across key sectors and in support of a 1.5°C-pathway.

Learn More about National Climate Strategies

After the U.S. withdrew from the Paris Agreement in 2017, CGS led the analysis of commitments from the more than 4,000 cities, states, businesses, universities, communities of faith, and more who pledged to support the goals of the Paris Agreement in their own capacity. Since the U.S. officially rejoined the Paris Agreement in March 2021, CGS has continued working with U.S. subnational and international partners to deliver analysis that informs how an "all-of-society" ambitious and achievable U.S. climate strategy can drive actionable and feasible policy. CGS informs U.S. climate policy from the local to global through developing integrated modeling and climate scenarios for the federal government, advising on international discussions to ramp up ambition, and collaborating from the bottom-up to move the resources necessary to set and achieve ambitious climate goals.

Learn More about U.S. Program

Rising to meet the ambition set out by our global climate commitments demands accelerated actions and commitments between all actors across our society: states, cities, businesses, universities, faith groups, and more. These sum-of-society actors have incredible leverage to impact the trajectory of greenhouse gas emissions, innovate across our economy, and accelerate the speed of the global clean energy transition.

Learn More about Subnational Climate Ambition Program
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School Authors: Christoph Bertram, Yiyun 'Ryna' Cui, Nathan Hultman, Gokul Iyer

Other Authors: Elina Brutschin, Laurent Drouet, Gunnar Luderer, Bas van Ruijven, Lara Aleluia Reis, Luiz Bernardo Baptista, Harmen-Sytze de Boer, Vassilis Daioglou, Florian Fosse, Dimitris Fragkiadakis, Oliver Fricko, Shinichiro Fujimori, Kimon Keramidas, Volker Krey, Elmar Kriegler, Robin D Lamboll, Rahel Mandaroux, Pedro Rochedo, Joeri Rogelj, Roberto Schaeffer, Diego Silva, Isabela Tagomori, Detlef van Vuuren, Zoi Vrontisi, Keywan Riahi