(ORDO NEWS) — In West Antarctica, a high rate of glacier retreat due to melting was recorded.
The floating part of these glaciers holds back the mass of ice that is on the coast, and its sliding can lead to a significant rise in sea levels. The researchers’ findings are published in the journal Nature Geoscience.
The area of the Amundsen Sea, into which the Pine Island, Thwaites, Pope, Smith, and Kohler glaciers descend, is known to be a major contributor to sea level rise. It is estimated that the entire mass of ice that is above the coastline is equivalent to a sea level rise of 1.2 meters.
Pine Island and Thwaites glaciers, considered the most dangerous, are losing record amounts of ice, but researchers have noticed that other glaciers are retreating due to a phenomenon called sea ice sheet instability.
It occurs when warm sea waters wash away the ground line – the boundary between the floating part of the glacier and the part that lies on the bottom.
Beginning in 2014, researchers have observed ground line retreat at the Pope, Smith, and Kohler Glaciers using interferometric synthetic aperture radar (InSAR) aboard the COSMO-SkyMed satellites. This data was combined with digital ice surface elevation models generated from observation of the TanDEM-X radar satellite.
It turned out that in 2017, the Pope Glacier retreated 3.5 kilometers in just 3.6 months, that is, the rate was 11.7 kilometers per year. Between 2016 and 2018, the Smith Glacier retreated 2 kilometers per year, while the Kohler Glacier retreated 1.3 kilometers per year.
Although retreat has slowed in 2018-2020, the annual retreat rate is still higher than numerical models suggest and faster than other glaciers in Antarctica and Greenland. Even the Thwaites and Pine Island glaciers are retreating at a slower rate of one kilometer per year.
The authors of the paper attribute the rapid retreat to the melting of ice in the resulting cavities near the ground line, where sea water penetrates.
Although the potential contribution of the studied glaciers to sea level rise is estimated at only six centimeters, scientists emphasize that the processes causing the retreat affect all glaciers in West Antarctica, including the most dangerous ones.
In the future, the results will help to more accurately determine the maximum contribution of this region to sea level rise in the coming decades.
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