Rapid, buoyancy-driven ice-sheet retreat of hundreds of metres per day
Rates of ice-sheet grounding-line retreat can be quantified from the spacing of corrugation ridges on deglaciated regions of the seafloor1,2, providing a long-term context for the approximately 50-year satellite record of ice-sheet change3,4,5. 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 satellite3,4,6,7 and marine-geological1,2 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.
Funding
Geological Survey of Norway (NGU)
Humanities and Social Sciences Faculty Research Fund, Newcastle University
Junior Research Fellowship, Peterhouse College, University of Cambridge
Prince Albert II of Monaco Foundation
History
School
- Social Sciences and Humanities
Department
- Geography and Environment
Published in
NatureVolume
617Issue
7959Pages
105-110Publisher
Nature ResearchVersion
- AM (Accepted Manuscript)
Rights holder
© The Author(s), under exclusive licence to Springer Nature LimitedPublisher statement
This version of the article has been accepted for publication, after peer review (when applicable) and is subject to Springer Nature’s AM terms of use, but is not the Version of Record and does not reflect post-acceptance improvements, or any corrections. The Version of Record is available online at: https://doi.org/10.1038/s41586-023-05876-1Acceptance date
2023-02-17Publication date
2023-04-05Copyright date
2023ISSN
0028-0836eISSN
1476-4687Publisher version
Language
- en