Scientists track rapid retreat of Antarctic glacier
Scientists are warning that apparently stable glaciers in the Antarctic can "switch very rapidly" and lose large quantities of ice as a result of warmer oceans.
Their finding comes after a research team led by Benjamin Wallis, a glaciologist at the University of Leeds, used satellites to track the Cadman Glacier, which drains into Beascochea Bay, on the west Antarctic peninsula. The researchers have published their analysis, "Ocean warming drives rapid dynamic activation of marine-terminating glacier on the west Antarctic Peninsula," in Nature Communications.
Between November 2018 and May 2021, the glacier retreated eight kilometers as the ice shelf at the end of the glacier—where ice extends out into the sea and is anchored onto the sea floor at what is known as the grounding zone—collapsed.
The ice shelf would have acted as a buttress, slowing the movement of the glacier towards the sea.
Surrounded by warmer ocean waters, the scientists believe the ice shelf thinned and became ungrounded, and the ice shelf was no longer able to hold back the glacier.
As a result, the speed at which the glacier was flowing rapidly accelerated—doubling its speed—increasing the amount of ice it discharges into the sea as icebergs, through a process known as iceberg calving.
Wallis said, "We were surprised to see the speed at which Cadman went from being an apparently stable glacier to one where we see sudden deterioration and significant ice loss.
The Cadman Glacier before and after the collapse of the ice shelf. The image on the left was taken in 2017 and shows the ice shelf. An image taken this month, on the right, shows the loss of the ice shelf. Credit: European Commission, European Space Agency, Copernicus Sentinel-2 Data, Benjamin Wallis
The mountainous and icy coastline of the Antarctic Peninsula. A marine terminating glacier in Antarctica. The image shows Antarctica but NOT Cadman Glacier. Credit: Professor Anna Hogg
Mountains and glaciers of the Antarctic Peninsula from above. A marine terminating glacier in Antarctica. The image shows Antarctica but NOT Cadman Glacier. Credit: Professor Anna Hogg