Melting from Under Greenland’s Ice Sheet Also Contributes to Sea-Level Rise

Nature Communications, June 8

Although most ice loss from Greenland comes from either surface melting, or icebergs breaking from outlet glaciers; a significant amount apparently is coming from melting occurring at the very bottom of the ice sheet, where it rests against bedrock. Some of this so-called “basal melting” occurs due to heat from geo-thermal activity, some from friction between the ice sheet and bedrock, and some from meltwater incursion. Although Greenland has been one of the largest sources of sea-level rise since the turn of the century, previous assessments have not included basal melt. Friction between the ice sheet and ground contributes about half of all basal melt, which currently totals about 20 gigatons each year, around 8% of total Greenland ice loss. Under a high-emissions scenario, these basal melt rates are expected to become five to seven times greater. Basal melt as the Arctic warms will accelerate the rate of both ice flow and surface melt, thus increasing the rate of Greenland ice loss.

https://www.nature.com/articles/s41467-021-23739-z