Zeb Nicholls
Guest Research Scholar
Integrated Climate Impacts Research Group
Energy, Climate, and Environment Program
Biography
Zebedee Nicholls is an expert in reduced complexity climate modeling currently associated with the Integrated Assessment and Climate Change Research Group of the IIASA Energy, Climate, and Environment Program. His research focuses on the development, evaluation, and application of reduced complexity models with a particular focus on the Model for the Assessment of Greenhouse Gas Induced Climate Change (MAGICC). Alongside Associate Professor Malte Meinshausen, he leads the Reduced Complexity Model Intercomparison Project (RCMIP). To facilitate this work and enhance reproducibility, he is committed to developing open-source scientific software and contributes to a number of projects (see github.com/znicholls and gitlab.com/znicholls).In the Intergovernmental Panel on Climate Change (IPCC) Sixth Assessment Report (AR6), he led the writing of Cross-Chapter Box 7.1 on reduced complexity models used for scenario classification in AR6, was a contributing author to Working Group 1 Chapters 1, 4, 5, 6, 7 and the Technical Summary, and Working Group 3’s Summary for Policy Makers, Chapter 3, and Annex C.
Nicholls completed his PhD at the Climate and Energy College within the University of Melbourne’s School of Geography, Earth, and Atmospheric Sciences in 2021. Prior to that, he completed his undergraduate Master’s course in Physics at St. John’s College, University of Oxford, where his thesis was supervised by Professor Myles Allen. He is currently working on the next phase of RCMIP, taking MAGICC open source and developing more regionally detailed emulators.
Last update: 14 SEP 2022
Publications
Aubry, T.J., Toohey, M., Khanal, S., Chim, M.M., Verkerk, M., Johnson, B., Schmidt, A., Kovilakam, M., Sigl, M., Nicholls, Z. , Thomason, L., Naik, V., Rieger, L., Stiller, D., Ziegler, E., Durack, P., & Smith, I.H. (2026). Stratospheric aerosol forcing for CMIP7 – Part 1: optical properties for pre-industrial, historical, and scenario simulations. Geoscientific Model Development 19 (9) 3725-3756. 10.5194/gmd-19-3725-2026.
Scheifinger, K. , Riahi, K. , Clarke, L., Huppmann, D. , Hasegawa, T., Luderer, G., Smith, C. , Kriegler, E., Rogelj, J. , Nicholls, Z. , van Vuuren, D., van Ruijven, B. , Dekker, M., Verpoort, P., Beath, H., & Sher, G. (2026). Key Benchmarks of Global Emissions Scenarios 2025: Annual update of integrated assessment scenarios and related benchmarks for limiting global warming. DOI:10.5194/egusphere-egu26-12960. In: EGU General Assembly 2026, 03 May - 08 May 2026, Vienna.
Lamb, W.F., Andrew, R.M., Jones, M., Nicholls, Z. , Peters, G.P., Smith, C. , Saunois, M., Grassi, G., Pongratz, J., Smith, S.J., Tubiello, F.N., Crippa, M., Gidden, M., Friedlingstein, P., Minx, J., & Forster, P.M. (2026). Differences in anthropogenic greenhouse gas emissions estimates explained. Earth System Science Data 18 (4) 2549-2572. 10.5194/essd-18-2549-2026.
Van Vuuren, D.P., O'Neill, B.C., Tebaldi, C., Sanderson, B.M., Chini, L.P., Friedlingstein, P., Hasegawa, T., Riahi, K. , Govindasamy, B., Bauer, N., Eyring, V., Fall, C.M.N., Frieler, K., Gidden, M.J. , Gohar, L.K., Högner, A. , Jones, A.D., Kikstra, J. , King, A., Knutti, R., Kriegler, E., Lawrence, Peter, Lennard, C., Lowe, J., Mathison, C., Mehmood, S., Nicholls, Z. , Prado, L.F., Zhang, Q., Rose, S.K., Ruane, A.C., Sandstad, M., Schleussner, C.-F. , Seferian, R., Sillmann, J., Smith, C., Sörensson, A.A., Panickal, S., Tachiiri, K., Vaughan, N., Vishwanathan, S.S., Yokohata, T., Zecchetto, M., & Ziehn, T. (2026). The Scenario Model Intercomparison Project for CMIP7 (ScenarioMIP-CMIP7). Geoscientific Model Development 19 (7) 2627-2656. 10.5194/gmd-19-2627-2026.
Tang, G., Zaehle, S., Nicholls, Z. , Norton, A., Ziehn, T., & Meinshausen, M. (2026). Understanding the Drivers of Carbon–Nitrogen Cycle Variability in CMIP6 ESMs With MAGICC CNit v2.0: Model and Calibration Updates. Journal of Advances in Modeling Earth Systems 18 (1) e2025MS005270. 10.1029/2025MS005270.