Thomas Gasser
Senior Research Scholar
Integrated Assessment and Climate Change Research Group
Energy, Climate, and Environment Program
Senior Research Scholar
Exploratory Modeling of Human-natural Systems Research Group
Advancing Systems Analysis Program
Biography
Thomas Gasser is a senior research scholar jointly associated with the Exploratory Modeling of Human-natural Systems Research Group of the IIASA Advancing Systems Analysis Program and the Integrated Assessment and Climate Change Research Group of the Energy, Climate, and Environment Program. He coordinates the “Earth system modeling” research theme.Gasser’s core expertise is in reduced-complexity modeling of the physical Earth system. His work focuses on improving and expanding reduced-complexity models and emulation techniques, on using these models to investigate policy-relevant aspects of climate change, and on linking physics-based emulators with the socioeconomic modeling tools available at IIASA. He is the main developer of the compact Earth system model OSCAR and a regular contributor to the Global Carbon Budget. He has also contributed to the Intergovernmental Panel on Climate Change (IPCC) Special Report on Global Warming of 1.5 °C and to the IPCC Sixth Assessment Report. He and his team are involved in a number of large-scale European projects, including Nunataryuk, CONSTRAIN, ESM2025: Earth System Models for the Future, and RESCUE (upcoming), as well as in more targeted ones such as the ERM: Medium Complexity Earth System Risk Management project.
Gasser holds a master-level diploma in multidisciplinary science from École Polytechnique, another in environmental engineering from Ponts ParisTech, and a PhD in climate sciences from Université Pierre et Marie Curie, all in France. Prior to working with IIASA, he conducted his doctoral research at the International Center for Development and Environment (CIRED) and his post-doctoral research at the IPSL Sciences Laboratory of Climate and the Environment (LSCE) in France, both on the dual topic of modeling couplings and feedbacks in the Earth system and quantifying the contribution of nations to human-induced climate change.
Google Scholar. ORCID. GitHub.
Last update: 11 FEB 2022
Publications
O’Sullivan, M., Friedlingstein, P., Sitch, S., Pongratz, J., Schwingshackl, C., Gasser, T. , Ciais, P., Arora, V., Kato, E., Knauer, J., Monier, E., Nützel, T., Sun, Q., Yuan, W., Yue, X., & Zaehle, S. (2026). An improved approach to estimate the natural land carbon sink. npj Climate and Atmospheric Science 9 (1) e29. 10.1038/s41612-025-01302-7.
Grassi, G., Ciais, P., & Gasser, T. (2026). China’s land carbon sinks: from improved estimates to opportunities for better management. Science Bulletin 71 (2) 213-216. 10.1016/j.scib.2025.11.031.
Ouyang, Z., Jackson, R.B., Saunois, M., Canadell, J.G., Zhao, Y., Morfopoulos, C., Krummel, P.B., Patra, P.K., Peters, G.P., Dennison, F., Gasser, T. , Archibald, A.T., Arora, V., Baudoin, G., Chandra, N., Ciais, P., Davis, S.J., Feron, S., Guo, F., Hauglustaine, D., Jones, C.D., Jones, M.W., Kato, E., Kennedy, D., Knauer, J., Lienert, S., Lombardozzi, D., Melton, J.R., Nabel, J.E.M.S., O’Sullivan, M., Pétron, G., Poulter, B., Rogelj, J. , Sandoval Calle, D., Smith, P., Suntharalingam, P., Tian, H., Wang, C., & Wiltshire, A. (2025). The global hydrogen budget. Nature 648 (8094) 616-624. 10.1038/s41586-025-09806-1.
Friedlingstein, P., O'Sullivan, M., Jones, M.W., Andrew, R.M., Bakker, D.C.E., Hauck, J., Landschützer, P., Le Quéré, C., Li, H., Luijkx, I.T., Peters, G.P., Peters, W., Pongratz, J., Schwingshackl, C., Sitch, S., Canadell, J.G., Ciais, P., Aas, K., Alin, S.R., Anthoni, P., Barbero, L., Bates, N.R., Bellouin, N., Benoit-Cattin, A., Berghoff, C.F., Bernardello, R., Bopp, L., Brasika, I.B.M., Chamberlain, M.A., Chandra, N., Chevallier, F., Chini, L.P., Collier, N.O., Colligan, T.H., Cronin, M., Djeutchouang, L., Dou, X., Enright, M.P., Enyo, K., Erb, M., Evans, W., Feely, R.A., Feng, L., Ford, D.J., Foster, A., Fransner, F., Gasser, T. , Gehlen, M., Gkritzalis, T., Goncalves De Souza, J., Grassi, G., Gregor, L., Gruber, N., Guenet, B., Gürses, Ö., Harrington, K., Harris, I., Heinke, J., Hurtt, G. C., Iida, Y., Ilyina, T., Ito, A., Jacobson, A. R., Jain, A. K., Jarníková, T., Jersild, A., Jiang, F., Jones, S. D., Kato, E., Keeling, R. F., Klein Goldewijk, K., Knauer, J., Kong, Y., Korsbakken, J. I., Koven, C., Kunimitsu, T., Lan, X., Liu, J., Liu, Z., Liu, Z., Lo Monaco, C., Ma, L., Marland, G., McGuire, P. C., McKinley, G. A., Melton, J., Monacci, N., Monier, E., Morgan, E. J., Munro, D. R., Müller, J. D., Nakaoka, S.-I., Nayagam, L. R., Niwa, Y., Nutzel, T., Olsen, A., Omar, A. M., Pan, N., Pandey, S., Pierrot, D., Qin, Z., Regnier, P. A. G., Rehder, G., Resplandy, L., Roobaert, A., Rosan, T. M., Rödenbeck, C., Schwinger, J., Skjelvan, I., Smallman, T. L., Spada, V., Sreeush, M. G., Sun, Q., Sutton, A. J., Sweeney, C., Swingedouw, D., Séférian, R., Takao, S., Tatebe, H., Tian, H., Tian, X., Tilbrook, B., Tsujino, H., Tubiello, F., van Ooijen, E., van der Werf, G., van de Velde, S. J., Walker, A., Wanninkhof, R., Yang, X., Yuan, W., Yue, X., & Zeng, J. (2025). Global Carbon Budget 2025. Earth System Science Data Discussions 2025 1-139. 10.5194/essd-2025-659. (In Press)
Friedlingstein, P., Le Quéré, C., O’Sullivan, M., Hauck, J., Landschützer, P., Luijkx, I.T., Li, H., van der Woude, A., Schwingshackl, C., Pongratz, J., Regnier, P., Andrew, R.M., Bakker, D.C.E., Canadell, J.G., Ciais, P., Gasser, T. , Jones, M.W., Lan, X., Morgan, E., Olsen, A., Peters, G.P., Peters, W., Sitch, S., & Tian, H. (2025). Emerging climate impact on carbon sinks in a consolidated carbon budget. Nature 649 98-103. 10.1038/s41586-025-09802-5.