Greenland's ice sheet melting faster than scientists previously estimated, study finds
Greenland's ice sheet is melting faster than scientists previously estimated, according to a study released Wednesday in the journal Nature, with the loss believed to be 20% worse than previously reported.
Since 1985, Greenland's ice sheet has lost approximately 5,091 square kilometers of ice researchers found using satellite imagery. Scientists said earlier estimates did not track melting at the edges of the ice sheets, known as calving, which measures ice breaking off at the terminus of a glacier.
Greenland's ice sheet loses about 193 square kilometers of ice per year, researchers found.
Study co-author Chad Greene and his colleagues said they qualified the extent of calving, which increased the scope of ice mass lost.
They combined "236,328 observations of glacier terminus positions" compiled from various public data sets to capture monthly ice melt. Their measurements found that between 1985 and 2022, almost every glacier in Greenland experienced some level of loss.
Scientists found that seasonal variability of glaciers could be a predictor of long-term loss of ice mass, with notable differences in melting during the summer and winter. The study found that during the summer, ocean warming and influxes of meltwater raise ice melting rates and can alter the thickness of the glacial ice. During the winter months, "a melange of sea ice and icebergs" can modify the glacial melt rate.
Researchers in the study noted that "this retreat does not appear to substantially contribute to sea level rise" because most of the glacier margins the scientists measured were already underwater. The loss, however, may play a part in ocean circulation patterns, and how heat energy is distributed across the planet.
However, scientists have previously found the Greenland ice sheet is the second-largest contributor to sea level rise. In an earlier study, scientists found that a single sheet melting was responsible for more than 17% of sea level rise between 2006 and 2018.
Glaciers and ice sheets melt faster than they can gather new snow and ice as global temperatures increase — particularly in the oceans, which absorb 90% of warming on the planet. Having both warmer air and warmer ocean water amplifies the loss of ice.
— Li Cohen contributed to this report.