Nature Communications, 7 November 2023
The glaciers of North Greenland hold enough ice to raise sea level by 2.1 meters, but have long been considered stable because of their protective ice shelves; which serve as a barrier between the main ice sheet and the ocean. However, a new study shows that this stability no longer holds. By analyzing thousands of satellite images, climate models, and field measurements, researchers found that ice shelves in North Greenland have lost more than 35% of their total volume since 1978, with three of them collapsing completely. The loss of these critical ice buffers is due primarily to a warming ocean, melting the ice shelves from beneath. As they become thinner, there is less resistance holding back the inland ice sheet. As a result, researchers observed an increase in ice discharge into the ocean, contributing further to sea level rise. As the ocean is only projected to warm further unless greenhouse gas emissions are radically reduced, the basal melting of ice shelves in North Greenland will only accelerate. Further ice shelf loss may destabilize sections of the ice sheet, leading to unstoppable future sea-level rise over several centuries.