Rapid, buoyancy-driven ice-sheet retreat of hundreds of metres per day. ...

• Main Authors: Batchelor, Christine L, Christie, Frazer DW, Ottesen, Dag, Montelli, Aleksandr, Evans, Jeffrey, Dowdeswell, Evelyn K, Bjarnadóttir, Lilja R, Dowdeswell, Julian A
• Format: Article in Journal/Newspaper
• Language: English
• Published: Springer Science and Business Media LLC 2023
• Subjects: glaciology; Scandinavian Ice Sheet; Antarctica; Antarctic Ice Sheet; Corrugation ridges; grounding line; grounding zone; bathymetry; continental shelf; Antarctic; Antarc*; Ice Sheet
• Online Access: https://dx.doi.org/10.17863/cam.95833; https://www.repository.cam.ac.uk/handle/1810/348407

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 change3-5. 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 ...