The floating ice shelves of northern Greenland, whose role is crucial in regulating the amount of fresh water released into the ocean, have lost more than a third of their volume since 1978, scientists warn in a study published Tuesday.
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Researchers from Denmark, the USA and France used thousands of satellite images, co
Combined with field measurements and modeling to reconstruct the evolution of these platforms that extend the glaciers to the water.
“Since 1978, northern Greenland’s ice shelves have lost more than 35% of their total volume, three of them have collapsed completely,” conclude the authors in the journal Nature Communications of the eight ice shelves present in the region.
“The main reason is that they melted due to the warming of the seawater below,” Romain Millan, researcher at CNRS and the University of Grenoble and lead author of the study, tells AFP.
“We have seen a very significant increase in melting since the 2000s, which is obviously linked to the increase in ocean temperatures in this sector and over this period,” he points out.
Melting of these platforms does not directly contribute to sea level rise.
On the other hand, these platforms play the role of a “dam” that regulates the amount of frozen fresh water poured from the cap into the ocean and, in turn, participates in this phenomenon.
The disappearance of these natural dams therefore has a significant impact on the glaciers, whose anchor points on the ground are receding and which are shedding more ice than before.
“For example, the Zachariæ Isstrøm glacier, which lost its platform in 2003, almost doubled the amount of ice it released into the ocean,” notes Romain Millan.
These conclusions are all the more alarming because the glaciers in this region were previously considered by scientists to be stable, in contrast to other more fragile areas of the polar ice cap, which began to weaken in the mid-1980s.
“What will happen in the future at the poles and at sea level will depend on policy decisions to reduce greenhouse gas emissions,” recalls the researcher about the climate in Dubai a few weeks before COP28 (November 30th – December 12th) . ).