Intriguing news again came from Antarctica - scientists have established for the first time that the permafrost in Antarctica is melting at an accelerating rate, and this is not associated with global warming, RIA-Novosti reports citing Scientific Reports.
Scientists led by Joseph Levy of the University of Texas at Austin (USA) have collected data on the melting of an underground glacier in the Garwood Valley, located in the McMurdo Dry Valleys region of Victoria Land in Antarctica.
Scientists found that the rate of permafrost melting increased from 2001 to 2012 and is now about 10 times the average rate for the current geological era.
Previously, it was believed that the underground ice of Antarctica is subject only to seasonal fluctuations. However, Levy and his colleagues showed that the permafrost in the Garwood Valley is melting, and there are no geological traces of such processes in the foreseeable past. They found that the 400-meter subsurface glacier in this valley is now losing about 5,000 cubic meters of ice per year and has shrunk by nearly 45,000 cubic meters since 2001-2002.
Scientists don't associate ice melting with warming. In the area of the Dry Valleys from 1986 to 2000, a cooling was observed, after which there was no rise in temperature. Researchers attribute the melting of permafrost to changes in weather conditions that have increased the amount of sunlight reaching the soil in the area.
Sunlight reflects well from the surface of the glacier, but the darker surface of the earth, under which the permafrost is hidden, absorbs more solar energy. A thick layer of sedimentary rocks protects the underground ice from the sun's heat, while a thin layer, on the contrary, heats up and warms the ice underneath.
Melting underground ice is changing the landscape as the soil settles above it.
In some places of the glacier, the subsidence has reached 15 meters since 2001. When the predicted rate of global warming is added to the impact of sunlight, ice melting and landscape shrinkage will accelerate, scientists predict.
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