Atmospheric Warming Combined with Meltwater Increases Ocean Melting of Greenland Glaciers

Nature Geoscience, 3 October 2022

While it was previously thought that ocean temperatures were the primary cause of melting along the ocean-based edges of the Greenland ice Sheet, new research suggests that atmospheric warming is equally important in this underwater melting, through the effects of meltwater running off the surface. Rising air temperatures increase melting on the ice sheet, producing streams of warm water that trickle through the ice. Once this meltwater reaches the ocean, it rises upwards in a plume of warm water that transfers its heat into the end of the glacier. Warm fjord waters are also carried up by these fast-moving freshwater plumes and further speed ice loss. In this way, atmospheric warming plays an essential role in controlling glacier retreat and iceberg production. This process appears to play a dominating role at least in northwest Greenland, and other regions of the Greenland Ice Sheet may be similarly vulnerable to these warm freshwater surges driven by surface melting. This study underscores the close interconnection of ice sheet health with its atmospheric surroundings, and emphasizes the need for urgent emission reductions to slow Greenland’s contribution to global sea level rise.

https://www.nature.com/articles/s41561-022-01035-9