Antarctic ice shelf disintegration triggered by sea ice loss and ocean swell

• Published in: Nature
• Main Authors: Massom, RA, Scambos, TA, Bennetts, LG, Reid, P, Squire, VA, Stammerjohn, SE
• Format: Article in Journal/Newspaper
• Language: English
• Published: Nature Publishing Group 2018
• Subjects: Earth Sciences; Physical geography and environmental geoscience; Glaciology; Antarctic; The Antarctic; Wilkins; Antarc*; Ice Sheet; Ice Shelf; Ice Shelves; Sea ice
• Online Access: https://doi.org/10.1038/s41586-018-0212-1; http://www.ncbi.nlm.nih.gov/pubmed/29899449; http://ecite.utas.edu.au/129182

Understanding the causes of recent catastrophic ice shelf disintegrations is a crucial step towards improving coupled models of the Antarctic Ice Sheet and predicting its future state and contribution to sea-level rise. An overlooked climate-related causal factor is regional sea ice loss. Here we show that for the disintegration events observed (the collapse of the Larsen A and B and Wilkins ice shelves), the increased seasonal absence of a protective sea ice buffer enabled increased flexure of vulnerable outer ice shelf margins by ocean swells that probably weakened them to the point of calving. This outer-margin calving triggered wider-scale disintegration of ice shelves compromised by multiple factors in preceding years, with key prerequisites being extensive flooding and outer-margin fracturing. Wave-induced flexure is particularly effective in outermost ice shelf regions thinned by bottom crevassing. Our analysis of satellite and ocean-wave data and modelling of combined ice shelf, sea ice and wave properties highlights the need for ice sheet models to account for sea ice and ocean waves.