Increase in Subsurface Lakes Under the Greenland Ice Sheet

The Cryosphere, June 29

Across the entire Greenland Ice Sheet, the extent of meltwater reservoirs hidden underneath layers of packed snow and ice increased by 56% from 2018 to 2019. This increase in “buried” lakes was caused by prolonged summer surface melt in conjunction with unusually high temperatures during the autumn. In the southwest region of Greenland, buried lakes form when pools of meltwater on the surface of the ice sheet freeze, and then become insulated by falling snow. In the southeast of Greenland, in contrast these lakes mostly form when meltwater trickles down through layers of snow and accumulates beneath the surface; or when strong sunlight penetrates the top layer of ice and creates slush beneath the surface. Authors emphasize the importance of surface meltwater on ice sheet dynamics, because an influx of meltwater can increase both ice flow velocity and mass loss, accelerating sea level rise.