Arctic & Antarctica
The image above depicts the mountainous and icy coastline of the Antarctic Peninsula. Credit: Professor Anna Hogg

Antarctica - Unstable Ice: Antarctic Glacier's Sudden Collapse Rattles Scientists

A recent study led by glaciologist Benjamin Wallis has revealed the alarming instability of the Antarctic’s Cadman Glacier, which rapidly lost significant ice due to ocean warming.

This highlights the urgent need for extensive ocean monitoring and raises concerns about other glaciers potentially facing similar rapid changes.

Scientists have found that even seemingly stable glaciers in the Antarctic can “switch very rapidly” and lose large quantities of ice as a result of warmer oceans. This alert follows a study by a team led by glaciologist Benjamin Wallis from the University of Leeds. Using satellite data, the team observed significant changes in the Cadman Glacier, located in the Beascochea Bay area of the West Antarctic Peninsula.

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.


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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.

Cadman Glacier
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

“What was also curious was that the neighboring glaciers on this part of the west Antarctic Peninsula did not react in the same way, which may hold important lessons for the way we can better project how climate change will continue to affect this important and sensitive polar region.

“Our study brought together data from three decades, nine different satellite missions, and in-situ oceanographic measurements to understand the changes happening in Antarctica. This demonstrates how important it is to have long-term monitoring of the Earth’s polar regions with a range of sensors which all tell us a different piece of the story.”

According to the scientists, the Cadman Glacier is now in a state of “substantial dynamic imbalance”. The ice on the glacier has continued to thin, with elevation being lost at a rate of around 20 meters a year. That is equivalent to a loss in height of a five-story building each year.

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