Figure ASatellite images from 2022 (Main image) and 1985 (Figure A) capture the retreat of Jakobshavn Isbrae, a glacier on Greenland's western coast, as icebergs broke off its edge over nearly four decades. In a recent study in Nature, researchers from NASA's Jet Propulsion Laboratory in Southern California calculated that Jakobshavn lost an estimated 97 billion tons (88 billion metric tons) of ice in the period between the two images.
The earlier image was taken by the Thematic Mapper instrument on the Landsat 5 satellite on Sept. 5, 1985, while the later image was captured by the Operational Land Imager on the Landsat 8 satellite on Sept. 4, 2022. Of the 207 glaciers analyzed in the study, Jakobshavn lost the second most ice mass, trailing only Zachariae Isstrom, a glacier in northeast Greenland.
Figure B is an annotated version of the 2022 image.
Figure BFigure C is an annotated version of the 1985 image.
Figure CThe study took a comprehensive look at glacial retreat around the edges of the entire Greenland Ice Sheet from 1985 to 2022 and found that 179 glaciers retreated significantly since 1985, 27 held steady, and just one advanced slightly.
The study found that overall the ice sheet shed about 1,140 billion tons (1,034 billion metric tons) of ice from 1985 to 2022, one-fifth more mass than previously estimated, as icebergs fell into the ocean at an accelerating rate.
Most of the ice loss came from below sea level, in fjords on Greenland's periphery. Once occupied by ancient glacial ice, many of these deep coastal valleys have filled with seawater – meaning the ice that broke off made little net contribution to sea level. But the loss likely accelerated the movement of ice flowing down from higher elevations, which in turn added to sea level rise. It also added previously unaccounted-for fresh water to the North Atlantic Ocean, which could have impacts on global ocean currents.
