ESM2025 is an ambitious European project on Earth System Modelling that aims to develop the next generation of Earth System Models (ESMs)

Developing a novel generation of ESMs will provide relevant climate simulations for the design of comprehensive climate change mitigation and adaptation strategies, in line with the Paris Agreement. This next generation of ESMs will include an improved representation of the full Earth-system response to anthropogenic emissions, with a particular focus on human land-use change.

ESM2025 is funded by the H2020 European Commission programme for 4 years. Led by Météo France-CNRM, it is carried out by an interdisciplinary team of 20 partners from 7 countries across Europe (Austria, Belgium, France, Germany, Norway, Sweden, Switzerland, and the UK) and Australia. The team is composed of Earth-system scientists and model developers, experts in machine learning and data-driven hybrid modelling, model evaluation and feedback analysis, as well as specialists in integrated assessment models, climate education and science-policy communication.

Project activities are divided into 4 core themes, ranging from scientific activities to knowledge exchange and outreach. The first three core themes are dedicated to research activities (from component development, process parameterization, couplings, to interactions with the Integrated Assessment Modelling community); the 4th is devoted to the dissemination and exchange of knowledge with stakeholders and the general public. Interactions between the 4 core themes are facilitated by dedicated cross-cutting actions and decision-making boards that link the different activities of the project to ensure their smooth running.

IIASA is a key contributor to WP11+12 Improving reduced-complexity carbon-cycle and climate models, that are part of the third core theme that aims to connect improved high-complexity ESMs with Integrated Assessment Models (IAMs) through the development and improvement of reduced-complexity models. IIASA also contributes to WP13 Assessment of robust and resilient climate action, that is part of the fourth core theme about operationalizing the Paris Agreement, outreach and knowledge exchange.

Partners

European Union © European Union

This project has received funding from the European Union’s Horizon 2020 Research and Innovation Programme under Grant Agreement No 101003536.

Published papers:

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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.

Tavoni, M., Bauer, N., Drouet, L., Fujimori, S. , Paltsev, S., Pirani, A., Riahi, K. , Rogelj, J. , Schaeffer, R., van Vuuren, D., Weitzel, M., & Kriegler, E. (2026). Implications of overshoot for climate mitigation strategies. Nature Climate Change 16 (3) 261-272. 10.1038/s41558-026-02563-7.

Gasser, T. , Rezai, A., Cheritel, C., Baklanov, A. , & Obersteiner, M. (2026). Negative emissions to mitigate Earth system risks. Nature Communications 10.1038/s41467-026-69896-x. (In Press)

Beath, H., Smith, C. , Kikstra, J. , Dekker, M.M., Gidden, M. , & Rogelj, J. (2026). A weighting framework to improve the use of emissions scenario ensembles of opportunity. Nature Climate Change 10.1038/s41558-026-02565-5. (In Press)

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.

Bodirsky, B.L., Beier, F., Humpenöder, F., Leip, D., Crawford, M.S., Chen, D.M.-C., von Jeetze, P., Springmann, M., Soergel, B., Nicholls, Z. , Strefler, J., Lewis, J. , Heinke, J., Müller, C., Karstens, K., Weindl, I., Stevanović, M., Rein, P., Sauer, P., Mishra, A., Bacca, E.J.M., Köberle, A.C., Wang, X., Singh, V., Hunecke, C., Collignon, Q., Schreinemachers, P., Dietz, S., Kanbur, R., Dietrich, J.P., Lotze-Campen, H., & Popp, A. (2025). A food system transformation pathway reconciles 1.5 °C global warming with improved health, environment and social inclusion. Nature Food 6 (12) 1133-1152. 10.1038/s43016-025-01268-y.

Zehrung, A., King, A.D., Nicholls, Z. , Zelinka, M.D., & Meinshausen, M. (2025). Standardising the “Gregory method” for calculating equilibrium climate sensitivity. Geoscientific Model Development 18 (23) 9433-9450. 10.5194/gmd-18-9433-2025.

Nauels, A. , Nicholls, Z. , Möller, T., Hermans, T.H.J., Mengel, M., Kloenne, U., Smith, C. , Slangen, A.B.A., & Palmer, M.D. (2025). Multi-century global and regional sea-level rise commitments from cumulative greenhouse gas emissions in the coming decades. Nature Climate Change 15 1198-1204. 10.1038/s41558-025-02452-5.

Nauels, A. , Nicholls, Z. , Möller, T., Hermans, T.H.J., Mengel, M., Kloenne, U., Smith, C. , Slangen, A.B.A., & Palmer, M.D. (2025). Multi-century global and regional sea-level rise commitments from cumulative greenhouse gas emissions in the coming decades. 10.5281/zenodo.16572777.

Dunne, J.P., Hewitt, H.T., Arblaster, J.M., Bonou, F., Boucher, O., Cavazos, T., Dingley, B., Durack, P.J., Hassler, B., Juckes, M., Miyakawa, T., Mizielinski, M., Naik, V., Nicholls, Z. , O'Rourke, E., Pincus, R., Sanderson, B.M., Simpson, I.R., & Taylor, K.E. (2025). An evolving Coupled Model Intercomparison Project phase 7 (CMIP7) and Fast Track in support of future climate assessment. Geoscientific Model Development 18 (19) 6671-6700. 10.5194/gmd-18-6671-2025.

Li, M., Wang, R., Zheng, X., Wang, C., & Rogelj, J. (2025). Repository for publication "Sharing emissions and removals for meeting the Paris Agreement through a distributive and corrective justice lens". 10.5281/zenodo.15649050.

Li, M., Wang, R., Zheng, X., Wang, C., & Rogelj, J. (2025). Sharing emissions and removals for meeting the Paris Agreement through a distributive and corrective justice lens. Environmental Research Letters 20 (10) e104028. 10.1088/1748-9326/adff2e.

Munday, G., Jones, C.D., Steinert, N.J., Mathison, C., Burke, E.J., Smith, C. , Huntingford, C., Varney, R.M., & Wiltshire, A.J. (2025). Risks of unavoidable impacts on forests at 1.5 °C with and without overshoot. Nature Climate Change 15 650-655. 10.1038/s41558-025-02327-9. (In Press)

Schöngart, S., Nicholls, Z. , Hoffmann, R., Pelz, S. , & Schleussner, C.-F. (2025). High-income groups disproportionately contribute to climate extremes worldwide. Nature Climate Change 15 627-633. 10.1038/s41558-025-02325-x.

Tang, G., Nicholls, Z. , Norton, A., Zaehle, S., & Meinshausen, M. (2025). Synthesizing global carbon–nitrogen coupling effects – the MAGICC coupled carbon–nitrogen cycle model v1.0. Geoscientific Model Development 18 (7) 2193-2230. 10.5194/gmd-18-2193-2025.

Tang, G., Nicholls, Z. , Jones, C., Gasser, T. , Norton, A., Ziehn, T., Romero-Prieto, A., & Meinshausen, M. (2025). Investigating carbon and nitrogen conservation in reported CMIP6 Earth system model data. Geoscientific Model Development 18 (7) 2111-2136. 10.5194/gmd-18-2111-2025.

Pelz, S. (2025). Replication archive for: "Using net-zero carbon debt to track climate overshoot responsibility". 10.5281/zenodo.14915596.

Pelz, S. , Ganti, G. , Lamboll, R., Grant, L., Smith, C. , Pachauri, S. , Rogelj, J. , Riahi, K. , Thiery, W., & Gidden, M.J. (2025). Using net-zero carbon debt to track climate overshoot responsibility. Proceedings of the National Academy of Sciences 122 (13) e2409316122. 10.1073/pnas.2409316122.

Ganti, G. , Pelz, S. , Klönne, U., Gidden, M.J. , Schleussner, C.F. , & Nicholls, Z. (2025). Fair carbon removal obligations under climate response uncertainty. Climate Policy 1-13. 10.1080/14693062.2025.2481138. (In Press)

Li, M., Pelz, S. , Lamboll, R., Wang, C., & Rogelj, J. (2025). A principle-based framework to determine countries’ fair warming contributions to the Paris Agreement. Nature Communications 16 (1) 10.1038/s41467-025-56397-6.