Achim Steiner

Achim Steiner was appointed Senior Fellow at the Oxford Martin School, University of Oxford, in January 2026, where he leads a global programme on ‘Security Futures’. He previously served as United Nations Under-Secretary-General and Administrator of the United Nations Development Programme (2017–2025), leading the UN’s largest development agency across more than 170 countries.

Earlier, he served as Executive Director of the United Nations Environment Programme (2006–2016), where he pioneered green economy policies and helped establish the UN Environment Assembly. His career has also included leadership roles at IUCN, the World Commission on Dams, the UN Office at Nairobi and the University of Oxford.

Steiner currently chairs the Hamburg Sustainability Conference and serves on several international councils and boards. Born in Brazil and holding Brazilian and German nationality, he studied at Oxford and SOAS and IDOS.

Amber D. Miller

Amber D. Miller is president of the $13 billion charitable William and Flora Hewlett Foundation, which invests in creative thinkers and problem solvers in more than 1,000 grantee organizations working to ensure meaningful opportunities to thrive for people, communities, and the planet. Before joining the foundation, Amber served as dean of the University of Southern California (USC) Dornsife College of Letters, Arts and Sciences, the largest school at USC, where she was responsible for managing a multidisciplinary institution with nearly 2,000 faculty and staff. Previously, she served as the inaugural dean of science at Columbia University, where she enhanced connections across science, engineering, medicine, and other specialties. Amber’s academic research has focused primarily on experimental cosmology. A California native, Amber received her bachelor’s degree in astronomy and physics from the University of California, Berkeley, and her doctorate in physics from Princeton University.

Suman Sureshbabu

In her role as VP, Suman works across program areas to guide strategy and collaboration. She brings over 20 years of global experience in philanthropy and inclusive economic development. Suman’s previous work includes renewable energy and jobs investments at the Global Energy Alliance for People and Planet (GEAPP) and economic opportunity in Africa and Asia at the Rockefeller Foundation. Suman holds a master’s from Princeton University.

Kerem Yilmaz

As a director of Advisory & Insights, Kerem leads efforts to advance knowledge and empower funders to make informed, high-impact decisions. His work focuses on addressing funding gaps and uncovering opportunities to accelerate climate action through strategic investments. Kerem has extensive experience in driving systemic change for climate mitigation and resilience, and holds a master’s from the University of Southern California.

Gabriel Francisco

As associate director, Gabriel coordinates the work of the Global Energy Transition Initiative in Latin America to achieve a low-carbon economy with an ecological transformation, focusing on Mexico, Colombia, and Brazil. Gabriel brings over a decade of experience as an energy policy advisor for the United States and Norway. He holds a master’s from the University of London.

Nikita Mistry

Nikita is an associate director and was previously the Deputy Director of Strategy for the UN Climate Change Conference in Dubai (COP28). She holds experience in the COP26 Presidency, Cabinet Office and other UK Government positions with a deep knowledge of philanthropy and environmental affairs. Nikita holds an bachelor’s from the University of Birmingham and a master’s from the School of Oriental and African Studies (University of London).

Sebastian Castellanos

Sebastian is the associate director of emerging economies at the Drive Electric Campaign. Sebastian’s expertise lies at the nexus of sustainable mobility, new technologies, and climate change governance. Previously, he supported governments’ transition to low-carbon transportation and led electric mobility teams. Sebastian holds master’s degrees from the École des Mines de Saint-Étienne and the University of Leeds.

Jonathan Pershing

Jonathan Pershing has extensive experience at the highest level of U.S. climate policy and has played a key role in creating international climate agreements. He has held significant positions in the U.S. Department of State — including as the U.S. Special Envoy for Climate Change — and at the U.S. Department of Energy, as well as leadership roles in the World Resources Institute and the International Energy Agency. Most recently, he has been the Director of the Environment Program at the Hewlett Foundation. As of January 2026 he has joined LSE’s Global School of Sustainability as the Inaugural Dean.

Justin Sylvester

Justin leads our Just Transition program to support energy transition initiatives in the Global South. With over 15 years of experience in philanthropy, he has led program strategies that foster accountable governance for local communities at the Ford Foundation and others. Justin holds a master’s from the University of Cape Town and is an independent Board member of Oxfam International.