Subglacial water amplifies Antarctic contributions to sea-level rise
Antarctica's contribution to global sea-level rise is deeply uncertain, with subglacial water suspected to play a critical role, yet its impact remains unclear. We demonstrate that water at the base of ice sheets influences sliding behaviour and that its exclusion from models can underestimate sea-level rise projections and delay the predicted onset of tipping points. Here we use an Antarctic Ice Sheet model (Elmer/Ice) to explore how different assumptions about water pressure at the ice base affect sea-level rise projections from 2015 to 2300. Our results indicate that incorporating subglacial water can amplify ice discharge across the Antarctic Ice Sheet by up to threefold above the standard approach, potentially contributing an additional 2.2 metres to sea-level rise by 2300. Notably, a smoothly decreasing basal drag near the grounding line more than doubles grounding line flux by 2300 relative to scenarios where effective pressure is simplified into a spatially constant coefficient. Basin-specific responses vary significantly, with some scenarios advancing tipping points by up to 40 years. These findings underscore the critical need to integrate evolving subglacial hydrology into ice sheet models.
Authors
- Poul Christoffersen (ORCID: https://orcid.org/0000-0003-2643-8724)
- Eliot Jager (ORCID: https://orcid.org/0000-0002-6493-0122)
- Justine Caillet (ORCID: https://orcid.org/0000-0001-9435-7585)
- Thomas Zwinger (ORCID: https://orcid.org/0000-0003-3360-4401)
- Chen Zhao (ORCID: https://orcid.org/0000-0003-0368-1334)
- Fabien Gillet‐Chaulet (ORCID: https://orcid.org/0000-0001-6592-3840)
- Matt A. King (ORCID: https://orcid.org/0000-0001-5611-9498)
- Yu Wang (ORCID: https://orcid.org/0000-0002-1809-0492)
- Pierre Mathiot (ORCID: https://orcid.org/0000-0002-2001-0762)
- Rupert Gladstone (ORCID: https://orcid.org/0000-0002-1582-3857)
- Benjamin K. Galton‐Fenzi (ORCID: https://orcid.org/0000-0003-1404-4103)
- Leopekka Saraste (ORCID: https://orcid.org/0009-0004-6548-2968)
Institutions
- Centre National de la Recherche Scientifique (FR)
- University of Tasmania (AU)
- Australian Antarctic Division (AU)
- University of Helsinki (FI)
- Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement (FR)
- Institut des Géosciences de l'Environnement (FR)
- CSC - IT Center for Science (Finland) (FI)
- Institut de Recherche pour le Développement (FR)
- Université Grenoble Alpes (FR)
- University of Lapland (FI)
Publication Details
- Journal
- Nature Communications
- Published
- 2025-04-07
- DOI
- https://doi.org/10.1038/s41467-025-58375-4
- Citations
- 4
- Primary Topic
- Cryospheric studies and observations
- Type
- article
- Field-Weighted Citation Impact
- 5.20
Funders
- Australian Government
- China Scholarship Council