About Ilissa Ocko

Ilissa Ocko

Senior Climate Scientist II, Barbra Streisand Chair of Environmental Studies


Areas of expertise:

Near-term climate change, short-lived climate pollutants (methane, hydrogen, aerosols), climate modeling, climate metrics, net zero


Dr. Ilissa Ocko is an applied climate scientist passionate about identifying and facilitating the most effective and pragmatic solutions to the current climate crisis. Her research explores the impacts of human-emitted climate pollutants and their mitigation on climate change both during our lifetimes and for generations to come. Dr. Ocko works closely with policy and business experts, economists, lawyers, and other scientists to translate the best available climate science into actionable strategies to curb climate change particularly in the coming decades. She is extremely passionate about communicating climate change science to non-experts using plain language, powerful visuals, and storytelling, and an avid creator of her own graphics and animations.


Dr. Ilissa Ocko leads Environmental Defense Fund’s climate science team. She earned a Ph.D. and M.A. in Atmospheric and Oceanic Sciences from Princeton University, and a B.S.E. in Earth System Science and Engineering from the University of Michigan. Dr. Ocko also holds a certificate in Science, Technology, and Environmental Policy from the Princeton School of Public and International Affairs. As an undergraduate she was a weather anchor on the university’s television network, and as a graduate student she began freelancing as a science graphic designer for organizations and universities. In 2016, Dr. Ocko won a U.S. science communications contest hosted by NASA, and went on to represent the U.S. in the international contest, advancing to the finals. In 2021, Dr. Ocko gave a TED talk on the fastest way to slow climate change, which now has over 2 million views.


  • Ph.D. and M.A., Atmospheric and Oceanic Sciences, Princeton University
  • B.S.E., Earth System Science and Engineering, University of Michigan — Ann Arbor


Esquivel-Elizondo, S, AH Mejia, T Sun, E Shrestha, SP Hamburg, IB Ocko, Wide range in estimates of hydrogen emissions from infrastructureFrontiers in Energy Research, 11 (2023)

Cohen-Shields, N, T Sun, SP Hamburg, IB Ocko, Distortion of sectoral roles in climate change threatens climate goals, Front. Clim. 5:1163557 (2023)

Ivanovich, CC, T Sun, DR Gordon, IB Ocko, Future warming from global food consumption, Nat. Clim. Chang. 13, 297–302 (2023)

Ocko, IB, SP Hamburg, Climate consequences of hydrogen emissions, Atmos. Chem. Phys., 22, 9349–9368 (2022)

Sun, T, IB Ocko, SP Hamburg, The value of early methane mitigation in preserving Arctic summer sea ice, Environ. Res. Lett., 17, 044001 (2022)

Allen, MR, GP Peters, KP Shine, C Azar, P Balcombe, O Boucher, M Cain, P Ciais, W Collins, PM Forster, DJ Frame, P Friedlingstein, C Fyson, T Gasser, B Hare, S Jenkins, SP Hamburg, DJA Johansson, J Lynch, A Macey, J Morfeldt, A Nauels, I Ocko, M Oppenheimer, SW Pacala, R Pierrehumbert, J Rogelj, M Schaeffer, CF Schleussner, D Shindell, RB Skeie, SM Smith, K Tanaka, Indicate separate contributions of long-lived and short-lived greenhouse gases in emission targets, npj Climate and Atmospheric Science, 5, 5 (2022)

Sun, T, IB Ocko, E Sturcken, SP Hamburg, Path to net zero is critical to climate outcome, Scientific Reports, 11, 22173 (2021)

Ocko, IB, T Sun, D Shindell, M Oppenheimer, AN Hristov, SW Pacala, DL Mauzerall, Y Xu, SP Hamburg, Acting rapidly to deploy readily available methane mitigation measures by sector can immediately slow global warming, Environ. Res. Lett., 16, 054042 (2021)

Ocko, IB, SP Hamburg, Climate Impacts of Hydropower: Enormous Differences among Facilities and over Time, Environ. Sci. Tech., 53(23), 14070-14082 (2019)

Ivanovich, CC, IB Ocko, P Piris-Cabezas, A Petsonk, Climate benefits of proposed carbon dioxide mitigation strategies for international shipping and aviation, Atmos. Chem. Phys., 19(23), 14949-14965 (2019)

Ocko, IB, V Naik, D Paynter, Rapid and reliable assessment of methane impacts on climate, Atmos. Chem. Phys., 18, 15555-15568, doi:10.5194/acp-18-15555-2018 (2018)

Ocko, IB, SP Hamburg, DJ Jacob, DW Keith, NO Keohane, M Oppenheimer, JD Roy-Mayhew, DP Schrag, SW Pacala, Unmask temporal trade-offs in climate policy debates, Science, 356, 6337, p.492-493 (2017)

Ocko, IB, and PA Ginoux (2017), Comparing multiple model-derived aerosol optical properties to spatially collocated ground-based and satellite measurements, Atmos. Chem. Phys., 17, 4451-4475, doi:10.5194/acp-17-4451-2017.

Ocko, IB, V Ramaswamy, Y Ming (2014), Contrasting climates responses to the scattering and absorbing features of anthropogenic aerosol forcings, J. Clim., 27, 5329-5345, doi:10.1175/JCLI-D-13-00401.1

Ocko, IB, V Ramaswamy, P Ginoux, Y Ming, and LW Horowitz (2012), Sensitivity of scattering and absorbing aerosol direct radiative forcing to physical climate factors, J. Geophys. Res., 117, D20203, doi:10.1029/2012JD018019.

Ocko, IB, Hot Seat in Our Warming World, Science, 337, 6092, p. 296, doi:10.1126/science.1224878 (2012)

Bankuti, M, B Ellis, M Frades, D Kanter, J Losh, I Ocko, J Roy-Mayhew, P Shevlin, C Sierawski, A Wasserman, J Zuckerman, D Mauzerall, Complements to carbon: Opportunities for near-term action on non-CO2 climate forcers, Policy Report, Princeton University (2011)