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 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 res...

Full description

Saved in:
Bibliographic Details
Published in:Nature (London) 2023-05, Vol.617 (7959), p.105-110
Main Authors: Batchelor, Christine L, Christie, Frazer D W, Ottesen, Dag, Montelli, Aleksandr, Evans, Jeffrey, Dowdeswell, Evelyn K, Bjarnadóttir, Lilja R, Dowdeswell, Julian A
Format: Article
Language:English
Subjects:
Antarctic ice sheet
Bathymetric data
Buoyancy
Corrugated sheet
Corrugation
Deglaciation
Ice
Ice sheets
Landforms
Marine geology
Ocean floor
Regions
Ridges
Satellites
Sea level rise
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary: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 km 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 , 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.
ISSN:0028-0836
1476-4687
1476-4687
DOI:10.1038/s41586-023-05876-1