Greenland ice sheet vulnerability under diverse climatic warming scenarios

Sea-level rise of even one meter will have drastic global impacts. Melting the Greenland Ice 16 Sheet (GIS) would raise sea level by 7.4 meters. There is an urgent need to improve predictions 17 of how quickly the GIS will contribute its first meter of sea-level rise, and from where on the ice 18 sheet that water will come. Estimating the volume of Greenland ice that was lost during past 19 warm periods offers a way to constrain the ice sheet’s likely response to future warming. Here, 20 we assess the sea-level potential across Greenland, based on an ensemble of ice-sheet model 21 simulations that represent a wide range of plausible deglaciation styles. The most vulnerable 22 region of the ice sheet is in West Greenland between approximately 64ºN and 76ºN, ranging 23 from ~10 to ~150 km behind the present-day ice margin. The ensemble spread for the most 24 stable regions of the GIS is sensitive to lithospheric feedbacks, while the most vulnerable GIS 25 region is predominantly sensitive to spatial climatology and precipitation lapse rate. These 26 results can guide future subglacial sampling by identifying regions and locations where such 27 data will have the greatest impact on our understanding of ice-sheet vulnerability/contribution to 28 sea-level rise in a warming world.