Melting of Greenland’s glaciers poses a ‘dramatic’ risk to the planet, study finds | Climate and science

Scientists believed that northern Greenland’s glaciers were stable, but a new study, published on Tuesday, showed that the region’s ice shelves have lost more than a third of their volume in the last 50 years. The area has enough ice to raise sea levels by more than two meters.

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Researchers analyzed thousands of satellite images and climate models. The study published in Nature Communications revealed that, since 1978, due to rising temperatures, the ice shelves in northern Greenland have lost more than 35% of their total volume. If the scenario continues, the consequences for the planet could be “dramatic”.

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.

Ice shelves are parts of a glacier form, which float on water. In northern Greenland, three of them collapsed and, of the five main ones that follow, there was a “general increase” in the amount of mass lost, mainly due to warming seas. According to researchers, one of the platforms, called Steenbsy, shrank to just 34% of its previous area between 2000 and 2013.

“The observed increase in melt coincides with a distinct increase in ocean potential temperature, suggesting strong oceanic control on ice shelf changes. We are able to identify a widespread and ongoing phase of weakening of the last remaining ice shelves in this sector,” say the authors in the study.

Melting ice underneath can also “play a complex and crucial role in shelf thinning.” When the layer becomes too thin, the structure is more likely to fracture.

“This makes them extremely vulnerable to unstable ice shelf retreat and collapse. If ocean thermal forcing continues to increase, which is likely to be the case over the next century, the consequences in terms of sea level rise will be dramatic”, continue the researchers.

Melting ice shelves themselves do not contribute to sea level rise since they are in the water. But they function as “dams” that regulate the discharge of ice into the ocean from the ice sheet. If these natural barriers disintegrate, glaciers could dump more ice into the oceans.

The researchers, based in Denmark, France and the United States, used thousands of satellite images combined with field measurements and climate models to reconstruct the nature of these floating glacier tracts.

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 currently accounts for around 17% of the sea level rise observed between 2006 and 2018.