More than 40% of Antarctica’s floating ice shelves have shrunk in the past 25 years, a phenomenon that could weaken their role as a barrier to continental ice sheet erosion, according to a study published Thursday in the American journal Science Advances scientist was published.
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Seventy-one of the White Continent’s 162 ice shelves shrank in volume between 1997 and 2021, releasing 7.5 trillion tons of melted water into the ocean, researchers estimated by analyzing more than 100,000 satellite images.
These freshwater platforms, an extension of the continent’s glaciers, act as a barrier between the sea and the continental cap, slowing the flow of glaciers into the ocean. These platforms can be hundreds of meters thick and as they shrink, their barrier function weakens, accelerating the melting of continental glaciers.
“Currently, Antarctica contributes only a relatively small proportion (6%) to sea level rise, but this proportion could increase significantly in the future if ice shelves continue to deteriorate,” he told AFP. Benjamin Davison, researcher at the University of Leeds (UK) and lead author of the study.
The melting particularly affected platforms in the west of Antarctica, which were exposed to warmer water, while those in the east, protected by a band of cold water, remained stable or increased in volume, the study said.
“Many ice shelves have deteriorated significantly: 48 of them have lost more than 30% of their original mass in 25 years,” Anna Hogg, co-author of the study and a professor at the university, said in a statement from Leeds.
“This is further evidence that Antarctica is changing as the climate warms,” she added.
The authors note that the reduction or disappearance of ice shelves could weaken deep-sea circulation, which plays an important role in the ocean’s absorption of carbon and heat.
“The ocean absorbs a lot of carbon and atmospheric heat, and the Southern Ocean, which surrounds Antarctica, is the largest contributor and is therefore an extremely important regulator of the global climate,” Mr Davison points out.
The Antarctic ice shelf, which is created by the freezing of seawater, has also been suffering from massive melting for several years. In February, in the middle of southern summer, it reached its historic low of 1.79 million square kilometers.