Benjamin Andrew Keisling, Joerg M. Schaefer, Robert DeConto, Jason P. Briner, Nicolás E. Young, Caleb Walcott, Gisela Winckler, Allie Balter-Kennedy , Sridhar Anandakrishnan

Sea-level rise of even one meter will have drastic global impacts. Melting the Greenland Ice Sheet (GIS) would raise sea level by 7.4 meters. There is an urgent need to improve predictions of how quickly the GIS will contribute its first meter of sea-level rise, and from where on the ice sheet that water will come. Estimating the volume of Greenland ice that was lost during past warm periods offers a way to constrain the ice sheet’s likely response to future warming. Here, we assess the sea-level potential across Greenland, based on an ensemble of ice-sheet model simulations that represent a wide range of plausible deglaciation styles. The most vulnerable region of the ice sheet is in West Greenland between approximately 64ºN and 76ºN, ranging from ~10 to ~150 km behind the present-day ice margin. The ensemble spread for the most stable regions of the GIS is sensitive to lithospheric feedbacks, while the most vulnerable GIS region is predominantly sensitive to spatial climatology and precipitation lapse rate. These results can guide future subglacial sampling by identifying regions and locations where such data will have the greatest impact on our understanding of ice-sheet vulnerability/contribution to sea-level rise in a warming world.