Impact of sliding laws and surface mass projections on Greenland outlet glacier dynamics at 100-year timescales

The Greenland Ice Sheet (GrIS) contributed to 10.6 mm to global sea level rise between 1992 and 2018, making it crucial to accurately forecast its near future ice losses. Here, we assess the relative importance of two major sources of uncertainty in GrIS ice loss, namely the choice of sliding law and SMB forecasts. To do this we use the ice flow model Úa to perform a series of model experiments using different formulations of the sliding law, and different projections of future surface mass balance (SMB). We conducted this work at three major Greenland outlet glaciers, to assess the variability in the importance of sliding laws and/or SMB forecasts between different types of glacier. Our results show that the choice of sliding law had a small impact on ice loss from our study glaciers, whereas the choice of SMB forecast produced major differences in sea level rise estimates.