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Robust projections of future sea-level rise are essential for coastal adaptation, yet they remain hampered by uncertainties in Antarctic ice-sheet projections–the largest potential contributor to sea-level change under global warming. Here, we combine two ice-sheet models, systematically sample parametric and climate uncertainties, and calibrate against historical observations to quantify Antarctic ice-sheet changes to 2300 and beyond. By 2300, the projected Antarctic sea-level contributions range from -0.09 m to +1.74 m under low emissions (SSP1-2.6, outer limits of 5-95% probability intervals), and from +0.73 m to +5.95 m under very high emissions (SSP5-8.5). Irrespective of the wide range of uncertainties explored, large-scale Antarctic ice-sheet retreat is triggered under SSP5-8.5, while reaching net-zero emissions well before 2100 strongly reduces multi-centennial ice loss. Yet, even under such strong mitigation, a significant sea-level contribution could still result from West Antarctica. Our results suggest that current mitigation efforts may not be sufficient to avoid self-sustained Antarctic ice loss, making emission decisions taken in the coming years decisive for future sea-level rise.
Even if net-zero emissions are reached well before 2100, West Antarctic ice-sheet retreat could still drive multi-meter sea-level rise by 2300. Emission reductions in the coming years are critical to limit long-term ice loss from Antarctica.
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; Klose, Ann Kristin 2
; Edwards, Tamsin 3
; Turner, Fiona 3 ; Pattyn, Frank 1
; Winkelmann, Ricarda 4
1 Université libre de Bruxelles (ULB), Laboratoire de Glaciologie, Brussels, Belgium (ROR: https://ror.org/01r9htc13) (GRID: grid.4989.c) (ISNI: 0000 0001 2348 6355)
2 Potsdam Institute for Climate Impact Research (PIK), Member of the Leibniz Association, Potsdam, Germany (ROR: https://ror.org/03e8s1d88) (GRID: grid.4556.2) (ISNI: 0000 0004 0493 9031); Department of Physics and Astronomy, University of Potsdam, Potsdam, Germany (ROR: https://ror.org/03bnmw459) (GRID: grid.11348.3f) (ISNI: 0000 0001 0942 1117)
3 King’s College London, Department of Geography, London, UK (ROR: https://ror.org/0220mzb33) (GRID: grid.13097.3c) (ISNI: 0000 0001 2322 6764)
4 Potsdam Institute for Climate Impact Research (PIK), Member of the Leibniz Association, Potsdam, Germany (ROR: https://ror.org/03e8s1d88) (GRID: grid.4556.2) (ISNI: 0000 0004 0493 9031); Department of Physics and Astronomy, University of Potsdam, Potsdam, Germany (ROR: https://ror.org/03bnmw459) (GRID: grid.11348.3f) (ISNI: 0000 0001 0942 1117); Integrative Earth System Science, Max Planck Institute of Geoanthropology, Jena, Germany (ROR: https://ror.org/00js75b59)