West Antarctic Ice Sheet retreat driven by Holocene warm water incursions.

• Main Authors: Hillenbrand, Claus-Dieter, Smith, James A, Hodell, David A, Greaves, Mervyn, Poole, Christopher R, Kender, Sev, Williams, Mark, Andersen, Thorbjørn Joest, Jernas, Patrycja E, Elderfield, Henry, Klages, Johann P, Roberts, Stephen J, Gohl, Karsten, Larter, Robert D, Kuhn, Gerhard
• Format: Article in Journal/Newspaper
• Language: English
• Published: Springer Science and Business Media LLC 2017
• Subjects: Antarctic Regions; Foraminifera; Freezing; Geologic Sediments; Global Warming; History; 19th Century; 20th Century; 21st Century; Ancient; Hot Temperature; Ice Cover; Models; Theoretical; Oceans and Seas; Reproducibility of Results; Seawater; Wind; Antarctic; Amundsen Sea; West Antarctic Ice Sheet; Buttress; Antarc*; Ice Sheet; Ice Shelf; Ice Shelves
• Online Access: https://www.repository.cam.ac.uk/handle/1810/266625; https://doi.org/10.17863/CAM.11512

Glaciological and oceanographic observations coupled with numerical models show that warm Circumpolar Deep Water (CDW) incursions onto the West Antarctic continental shelf cause melting of the undersides of floating ice shelves. Because these ice shelves buttress glaciers feeding into them, their ocean-induced thinning is driving Antarctic ice-sheet retreat today. Here we present a multi-proxy data based reconstruction of variability in CDW inflow to the Amundsen Sea sector, the most vulnerable part of the West Antarctic Ice Sheet, during the Holocene epoch (from 11.7 thousand years ago to the present). The chemical compositions of foraminifer shells and benthic foraminifer assemblages in marine sediments indicate that enhanced CDW upwelling, controlled by the latitudinal position of the Southern Hemisphere westerly winds, forced deglaciation of this sector from at least 10,400 years ago until 7,500 years ago-when an ice-shelf collapse may have caused rapid ice-sheet thinning further upstream-and since the 1940s. These results increase confidence in the predictive capability of current ice-sheet models.