Satellite observation data helped to find out what processes are causing the bottom of the Antarctic glaciers to melt faster than before.
A team of scientists from several British universities found that the area of the glaciers surrounding Antarctica is rapidly shrinking due to the flows of warm ocean water, forcing the bottom of the glaciers to melt. 10.7% of the surveyed boundaries "retreat" towards Antarctica at a speed of 25 meters per year or faster. The study is published in the journal Nature Geoscience.
The work is based on satellite observations from 2010 to 2016. Scientists investigated the Antarctic grounding lines - the boundaries of the glacial bed, where the floating parts of the glaciers lie on the ground and intersect. The satellites scanned about 16 thousand kilometers of overlapping lines, that is, about a third of the lines surrounding Antarctica.
The researchers found that each year, the bottom portions of the glaciers lose about 200 square kilometers of ice. It rises to the surface of the water, and the overlapping line recedes towards Antarctica. This process is indirectly related to the rise in the water level in the oceans, which in the long term may threaten the ecological situation in many cities. According to the study, 10.7% of lines retreat relatively quickly, at a rate of 25 meters per year or faster. Only 1.9% of the territories “grow” at the same rate - scientists believe that the glacier growth may be associated with increased snowfall.
Offset of bump lines / Hannes Konrad et al, University of Leeds.
The researchers say that the main reason for the reduction in the area of the bottom parts of the glacier is the streams of warm water that erode the lower part of the ice massif. This process is most rapid in West Antarctica, where the Thwaites Glacier is located. In its central part, the overlap line recedes annually by 300-400 meters. The authors of the new work found that the rate of destruction of the Thwaites Glacier increased significantly from 1996 to 2011. In East Antarctica, scientists are concerned about the Totten Glacier. Previously, it was assumed that it could quickly collapse due to warm winds.
The authors of the work believe that the floating bottom ice affects both the water level in the ocean and the behavior of the glacier lying on the ground. Further research will help to identify the zones where bottom ice is melting most actively.
Natalia Peleznev
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