Greenland ice melting a major risk – 11/07/2023 – Environment

The floating ice shelves of northern Greenland have lost a third of their volume in the last four decades, shows a study published this Tuesday (7). This situation could generate a “dramatic” rise in sea level, according to the research authors.

These floating platforms play a crucial role in regulating the flow of ice from the region’s glaciers into the ocean. These glaciers contain enough ice to raise sea levels by 7 feet.

Since 1978, these platforms have lost more than 35% of their total volume, and three of them have completely collapsed, according to the study.

Because of global warming fueled by the use of fossil fuels, ice shelves are “extremely vulnerable” to further retreat and may even be doomed to collapse, according to the study published in Nature Communications.

“This could have dramatic consequences in terms of sea level rise,” the authors said.

Melting ice shelves themselves do not contribute to sea level rise, since they are already in the water. But they function like dams that regulate the discharge of ice into the ocean. If these natural barriers disintegrate, glaciers could end up dumping more ice into the oceans.

In the past, the glaciers in this region were considered stable by scientists, unlike other parts of the Greenland ice sheet, which began to weaken in the mid-1980s.

The study authors found, however, that the glaciers began to discharge ice in response to the weakening of the shelves, which have been melting at their bottom due to warming oceans.

“We identified a very significant increase in melting since the 2000s, which clearly corresponds to an increase in ocean temperatures in this area during that period,” said lead author Romain Millan, a researcher at the National Center for Scientific Research (CNRS, in French).

The researchers, from Denmark, France and the United States, used thousands of satellite images combined with field measurements and climate models to reconstruct the nature of the floating glaciers.

North Greenland’s glaciers have only begun to destabilize in the last 20 years, meaning more ice has been lost than gained. The Greenland ice sheet now accounts for approximately 17% of the sea level rise observed from 2006 to 2018.