Greenland Ice Loss 20% Higher Than Previously Estimated

Nature, 17 January 2024

New measurements reveal that the Greenland Ice Sheet lost 20% more ice over the past four decades than previously thought, with serious implications for global weather patterns, ocean circulation, ecosystems and food security. This study offers the most accurate assessment of Greenland ice loss to-date. While previous research focused on tracking the height and weight of the ice sheet, those methods did not account for ice loss from portions of outlet glaciers that lie below sea level in narrow fjords around Greenland. In this study, authors analyzed four decades of satellite data to track the end position of Greenland’s glaciers every month. Their key finding: Greenland has lost more than one trillion tons of ice along its margins since 1985 due to glacier retreat alone; in other words, not including surface melt on the massive ice sheet itself. Today, Greenland releases 30 million tons of ice every hour, and nearly every glacier in this ice sheet has thinned or retreated over the past few decades. The researchers raised concerns that this tremendous added amount of freshwater pouring into the north Atlantic could trigger slowdown or collapse of the Atlantic Meridional Overturning Circulation (AMOC), a major system of ocean currents. The authors also found that glaciers with large seasonal cycles of winter advance and summer retreat are the most susceptible to climate warming; and caution that these glaciers could undergo dramatic added ice loss should temperatures continue to rise, due to lack of the needed urgent reductions in fossil fuel emissions required to hold global temperature rise close to 1.5°C.

https://www.nature.com/articles/s41586-023-06863-2