Last Interglacial subsurface warming on the Antarctic shelf triggered by reduced deep-ocean convection
Abstract The Antarctic ice-sheet could have contributed 3 to 5 m sea-level equivalent to the Last Interglacial sea-level highstand. Such an Antarctic ice-mass loss compared to pre-industrial requires a subsurface warming on the Antarctic shelf of ~ 3 °C according to ice-sheet modelling studies. Here...
Published in: | Communications Earth & Environment |
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Main Authors: | , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Nature Portfolio
2024
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Subjects: | |
Online Access: | https://doi.org/10.1038/s43247-024-01383-x https://doaj.org/article/f28a62a08a3e451199c6299ed35f36e6 |
Summary: | Abstract The Antarctic ice-sheet could have contributed 3 to 5 m sea-level equivalent to the Last Interglacial sea-level highstand. Such an Antarctic ice-mass loss compared to pre-industrial requires a subsurface warming on the Antarctic shelf of ~ 3 °C according to ice-sheet modelling studies. Here we show that a substantial subsurface warming is simulated south of 60 °S in an equilibrium experiment of the Last Interglacial. It averages +1.2 °C at ~ 500 m depth from 70 °W to 160 °E, and it reaches +2.4 °C near the Lazarev Sea. Weaker deep-ocean convection due to reduced sea-ice formation is the primary driver of this warming. The associated changes in meridional density gradients and surface winds lead to a weakened Antarctic Circumpolar Current and strengthened Antarctic Slope Current, which further impact subsurface temperatures. A subsurface warming on the Antarctic shelf that could trigger ice-mass loss from the Antarctic ice-sheet can thus be obtained during warm periods from reduced sea-ice formation. |
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