Effects of extreme melt events on ice flow and sea level rise of the Greenland Ice Sheet
Abstract. Over the past decade, Greenland has experienced several extreme melt events, the most pronounced ones in the years 2010, 2012 and 2019. With progressing climate change, such extreme melt events can be expected to occur more frequently and potentially become more severe and persistent. So far, however, projections of ice loss and sea-level change from Greenland typically rely on scenarios which only take gradual changes in the climate into account. Using the Parallel Ice Sheet Model (PISM), we investigate the effect of extreme melt events on the overall mass balance of the Greenland Ice Sheet and the changes in ice flow, invoked by the altered surface topography. As a first constraint, this study estimates to the overall effect of extreme melt events on the cumulative mass loss of the Greenland Ice Sheet. We find that the sea-level contribution from Greenland might increase by 2 to 45 cm by the year 2300 if extreme events occur more frequently in the future, and the ice-sheet area might be reduced by an additional 1500 to 18000 km2 by 2300 in comparison to future warming scenarios without extremes. We conclude that both changes in the frequency and intensity of extreme events need to be taken into account when projecting the future sea-level contribution from the Greenland Ice Sheet.
