EGUsphere EGUsphere EGUsphere EGUsphere Copernicus Publications Göttingen, Germany 10.5194/egusphere-2026-6030 Increased future ice loss due to nested ice-climate feedbacks if Antarctic heatwaves intensify Nicola Lena https://orcid.org/0000-0002-1748-7420 1 2 3 4 Beckmann Johanna https://orcid.org/0000-0002-6862-6478 4 5 McCormack Felicity S. https://orcid.org/0000-0002-2324-2120 4 5 Winkelmann Ricarda https://orcid.org/0000-0003-1248-3217 1 2 3 Department of Integrative Earth System Science, Max Planck Institute of Geoanthropology, Kahlaische Str. 10, 07745 Jena, Germany Potsdam Institute for Climate Impact Research (PIK), Member of the Leibniz Association, P.O. Box 60 12 03, 14412 Potsdam, Germany Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht-Str. 24–25, 14476 Potsdam, Germany School of Earth, Atmosphere and Environment, Monash University, Clayton, Kulin Nations, Victoria, Australia Securing Antarctica’s Environmental Future, Monash University, Clayton, Kulin Nations, Victoria, Australia 12 10 2026 2026 1 30 Copyright: © 2026 Lena Nicola et al. 2026 This work is licensed under the Creative Commons Attribution 4.0 International License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/4.0/ This article is available from https://egusphere.copernicus.org/preprints/2026/egusphere-2026-6030/ The full text article is available as a PDF file from https://egusphere.copernicus.org/preprints/2026/egusphere-2026-6030/egusphere-2026-6030.pdf

Record-breaking extreme events, including heatwaves leading to surface melt and extreme snowfall, have been observed in Antarctica in recent years. Such extreme events are generally expected to become more frequent and intense with anthropogenic climate change. However, they are not typically considered in the climatic forcing used as the surface boundary condition for ice-sheet models projecting Antarctic mass changes into the future. With a suite of numerical ice-sheet simulations, we explore the additional Antarctic contribution to future sea-level rise when including atmospheric temperature extremes of varying frequency and intensity in projections. Our results suggest that by 2100, increasingly severe and frequent heatwaves have a limited effect on sea-level rise. However, by 2300, atmospheric extreme events could amplify sea-level rise by more than 2 m as atmosphere impacts on Antarctica contribute, rather than mitigate, ice loss. This study also highlights substantial uncertainties in ice-atmosphere interactions (e.g. the role of surface albedo) that amplify the sea-level rise response in an interlinked manner and play a key role in determining future sea-level rise.

 Studienstiftung des Deutschen Volkes PhD Stipend Carl-Zeiss-Stiftung CZS Research Groups for Earth System Modelling Australian Research Council Special Research Initiative (SRI) Securing Antarctica’s Environmental Future (SR200100005) ARC Discovery Early Career Research Award (DE210101433) HORIZON EUROPE Food, Bioeconomy, Natural Resources, Agriculture and Environment Ocean Cryosphere Exchanges in ANtarctica: Impacts on Climate and the Earth system, OCEAN ICE (101060452)