Disentangling the drivers of future Antarctic ice loss with a historically calibrated ice-sheet model
<p>We use an observationally calibrated ice-sheet model to investigate the future trajectory of the Antarctic ice sheet related to uncertainties in the future balance between sub-shelf melting and ice discharge, on the one hand, and the surface mass balance, on the other. Our ensemble of simul...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2024-02-01
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| Series: | The Cryosphere |
| Online Access: | https://tc.copernicus.org/articles/18/653/2024/tc-18-653-2024.pdf |
| _version_ | 1797316409944965120 |
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| author | V. Coulon A. K. Klose A. K. Klose C. Kittel T. Edwards F. Turner R. Winkelmann R. Winkelmann F. Pattyn |
| author_facet | V. Coulon A. K. Klose A. K. Klose C. Kittel T. Edwards F. Turner R. Winkelmann R. Winkelmann F. Pattyn |
| author_sort | V. Coulon |
| collection | DOAJ |
| description | <p>We use an observationally calibrated ice-sheet model to investigate the future trajectory of the Antarctic ice sheet related to uncertainties in the future balance between sub-shelf melting and ice discharge, on the one hand, and the surface mass balance, on the other. Our ensemble of simulations, forced by a panel of climate models from the sixth phase of the Coupled Model Intercomparison Project (CMIP6), suggests that the ocean will be the primary driver of short-term Antarctic mass loss, initiating ice loss in West Antarctica already during this century. The atmosphere initially plays a mitigating role through increased snowfall, leading to an Antarctic contribution to global mean sea-level rise by 2100 of 6 (<span class="inline-formula">−</span>8 to 15) cm under a low-emission scenario and 5.5 (<span class="inline-formula">−</span>10 to 16) cm under a very high-emission scenario. However, under the very high-emission pathway, the influence of the atmosphere shifts beyond the end of the century, becoming an amplifying driver of mass loss as the ice sheet's surface mass balance decreases. We show that this transition occurs when Antarctic near-surface warming exceeds a critical threshold of <span class="inline-formula">+</span>7.5 <span class="inline-formula"><sup>∘</sup></span>C, at which the increase in surface runoff outweighs the increase in snow accumulation, a signal that is amplified by the melt–elevation feedback. Therefore, under the very high-emission scenario, oceanic and atmospheric drivers are projected to result in a complete collapse of the West Antarctic ice sheet along with significant grounding-line retreat in the marine basins of the East Antarctic ice sheet, leading to a median global mean sea-level rise of 2.75 (6.95) m by 2300 (3000). Under a more sustainable socio-economic pathway, we find that the Antarctic ice sheet may still contribute to a median global mean sea-level rise of 0.62 (1.85) m by 2300 (3000). However, the rate of sea-level rise is significantly reduced as mass loss is likely to remain confined to the Amundsen Sea Embayment, where present-day climate conditions seem sufficient to commit to a continuous retreat of Thwaites Glacier.</p> |
| first_indexed | 2024-03-08T03:19:01Z |
| format | Article |
| id | doaj.art-bfefc7dfb2454398b0b9d4f3dcb37b47 |
| institution | Directory Open Access Journal |
| issn | 1994-0416 1994-0424 |
| language | English |
| last_indexed | 2024-03-08T03:19:01Z |
| publishDate | 2024-02-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | The Cryosphere |
| spelling | doaj.art-bfefc7dfb2454398b0b9d4f3dcb37b472024-02-12T12:56:11ZengCopernicus PublicationsThe Cryosphere1994-04161994-04242024-02-011865368110.5194/tc-18-653-2024Disentangling the drivers of future Antarctic ice loss with a historically calibrated ice-sheet modelV. Coulon0A. K. Klose1A. K. Klose2C. Kittel3T. Edwards4F. Turner5R. Winkelmann6R. Winkelmann7F. Pattyn8Université libre de Bruxelles (ULB), Laboratoire de Glaciologie, Brussels, BelgiumPotsdam Institute for Climate Impact Research (PIK), Member of the Leibniz Association, P.O. Box 6012 03, 14412 Potsdam, GermanyInstitute of Physics and Astronomy, University of Potsdam, Potsdam, GermanyInstitut des Géosciences de l'Environnement (IGE), Univ. Grenoble Alpes/CNRS/IRD/G-INP, Grenoble, FranceDepartment of Geography, King's College London, London, UKDepartment of Geography, King's College London, London, UKPotsdam Institute for Climate Impact Research (PIK), Member of the Leibniz Association, P.O. Box 6012 03, 14412 Potsdam, GermanyInstitute of Physics and Astronomy, University of Potsdam, Potsdam, GermanyUniversité libre de Bruxelles (ULB), Laboratoire de Glaciologie, Brussels, Belgium<p>We use an observationally calibrated ice-sheet model to investigate the future trajectory of the Antarctic ice sheet related to uncertainties in the future balance between sub-shelf melting and ice discharge, on the one hand, and the surface mass balance, on the other. Our ensemble of simulations, forced by a panel of climate models from the sixth phase of the Coupled Model Intercomparison Project (CMIP6), suggests that the ocean will be the primary driver of short-term Antarctic mass loss, initiating ice loss in West Antarctica already during this century. The atmosphere initially plays a mitigating role through increased snowfall, leading to an Antarctic contribution to global mean sea-level rise by 2100 of 6 (<span class="inline-formula">−</span>8 to 15) cm under a low-emission scenario and 5.5 (<span class="inline-formula">−</span>10 to 16) cm under a very high-emission scenario. However, under the very high-emission pathway, the influence of the atmosphere shifts beyond the end of the century, becoming an amplifying driver of mass loss as the ice sheet's surface mass balance decreases. We show that this transition occurs when Antarctic near-surface warming exceeds a critical threshold of <span class="inline-formula">+</span>7.5 <span class="inline-formula"><sup>∘</sup></span>C, at which the increase in surface runoff outweighs the increase in snow accumulation, a signal that is amplified by the melt–elevation feedback. Therefore, under the very high-emission scenario, oceanic and atmospheric drivers are projected to result in a complete collapse of the West Antarctic ice sheet along with significant grounding-line retreat in the marine basins of the East Antarctic ice sheet, leading to a median global mean sea-level rise of 2.75 (6.95) m by 2300 (3000). Under a more sustainable socio-economic pathway, we find that the Antarctic ice sheet may still contribute to a median global mean sea-level rise of 0.62 (1.85) m by 2300 (3000). However, the rate of sea-level rise is significantly reduced as mass loss is likely to remain confined to the Amundsen Sea Embayment, where present-day climate conditions seem sufficient to commit to a continuous retreat of Thwaites Glacier.</p>https://tc.copernicus.org/articles/18/653/2024/tc-18-653-2024.pdf |
| spellingShingle | V. Coulon A. K. Klose A. K. Klose C. Kittel T. Edwards F. Turner R. Winkelmann R. Winkelmann F. Pattyn Disentangling the drivers of future Antarctic ice loss with a historically calibrated ice-sheet model The Cryosphere |
| title | Disentangling the drivers of future Antarctic ice loss with a historically calibrated ice-sheet model |
| title_full | Disentangling the drivers of future Antarctic ice loss with a historically calibrated ice-sheet model |
| title_fullStr | Disentangling the drivers of future Antarctic ice loss with a historically calibrated ice-sheet model |
| title_full_unstemmed | Disentangling the drivers of future Antarctic ice loss with a historically calibrated ice-sheet model |
| title_short | Disentangling the drivers of future Antarctic ice loss with a historically calibrated ice-sheet model |
| title_sort | disentangling the drivers of future antarctic ice loss with a historically calibrated ice sheet model |
| url | https://tc.copernicus.org/articles/18/653/2024/tc-18-653-2024.pdf |
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