Rapid, buoyancy-driven ice-sheet retreat of hundreds of metres per day
Batchelor, C.L.; Christie, F.D.W.; Ottesen, D.; Montelli, A.; Evans, J.; Dowdeswell, E.K.; Bjarnadóttir, L.R.; Dowdeswell, J.A. (2023). Rapid, buoyancy-driven ice-sheet retreat of hundreds of metres per day. Nature (Lond.) 617(7959): 105-110. https://dx.doi.org/10.1038/s41586-023-05876-1
In: Nature: International Weekly Journal of Science. Nature Publishing Group: London. ISSN 0028-0836; e-ISSN 1476-4687, meer
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| Auteurs | | Top |
- Batchelor, C.L.
- Christie, F.D.W.
- Ottesen, D.
- Montelli, A.
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- Evans, J.
- Dowdeswell, E.K.
- Bjarnadóttir, L.R.
- Dowdeswell, J.A.
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| Abstract |
Rates of ice-sheet grounding-line retreat can be quantified from the spacing of corrugation ridges on deglaciated regions of the seafloor providing a long-term context for the approximately 50-year satellite record of ice-sheet change. However, the few existing examples of these landforms are restricted to small areas of the seafloor, limiting our understanding of future rates of grounding-line retreat and, hence, sea-level rise. Here we use bathymetric data to map more than 7,600 corrugation ridges across 30,000 km2 of the mid-Norwegian shelf. The spacing of the ridges shows that pulses of rapid grounding-line retreat, at rates ranging from 55 to 610 m day−1, occurred across low-gradient (±1°) ice-sheet beds during the last deglaciation. These values far exceed all previously reported rates of grounding-line retreat across the satellite and marine-geological records. The highest retreat rates were measured across the flattest areas of the former bed, suggesting that near-instantaneous ice-sheet ungrounding and retreat can occur where the grounding line approaches full buoyancy. Hydrostatic principles show that pulses of similarly rapid grounding-line retreat could occur across low-gradient Antarctic ice-sheet beds even under present-day climatic forcing. Ultimately, our results highlight the often-overlooked vulnerability of flat-bedded areas of ice sheets to pulses of extremely rapid, buoyancy-driven retreat. |
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