by Antarctica’s Thwaites Glacier, also known as Doomsday Glacier, is melting in unexpected ways that could lead to its rapid collapse, a new study has revealed.
Two teams of scientists have used an underwater robot and drilled deep holes the size of Florida Thwaites Glacier to study the melting patterns in unprecedented detail.
The researchers from the International Thwaites Glacier Collaboration discovered that while the overall melting of ice is slower than expected, melting in cracks and crevices and other vulnerable areas is much faster. Thwaites Glacier is often called the “Doomsday Glacier” because of its collapse catastrophic sea level rise.
“Our results are a surprise, but the glacier is still in trouble,” said British Antarctic Survey oceanographer and research team member Peter Davis. a statement. (opens in a new tab) “If an ice shelf and a glacier are in balance, the ice coming off the continent will match the amount of ice lost through melting and calving of icebergs. What we have found is that despite small amounts of melting, there is still rapid retreat of the glacier . , so it seems that it doesn’t take much to push the glacier out of balance.”
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Thwaites Glacier is located in West Antarctica and covers 74,000 square miles (192,000 square kilometers). One part of the glacier protrudes into the sea and holds back the rest of the ice mass lying on the bedrock, preventing it from sliding from land to sea.
Because the Thwaites Glacier slopes down towards the sea, it is particularly vulnerable to climate and sea temperature changes that can lead to rapid and irreversible ice loss. The collapse of Thwaites would cause sea levels to rise by around 2 feet (65 centimeters). This in turn could destabilize nearby glaciers, potentially raising future sea levels by almost another 3 metres.
To assess Thwaites Glacier’s vulnerability to collapse, the two groups observed ice-melt rates and the properties of the glacier and its surrounding ocean by lowering instruments via a 1,925-foot (587-meter) deep hole drilled into the ice and by launching a torpedo-shaped underwater robot called Icefin under the glacier.
Icefin is particularly useful for examining the grounding zone of Thwaites, the point where the glacier touches the sea floor, which has previously been almost impossible to study. The grounding zone of this glacier has retreated by 8.7 miles (14 kilometers) since the 1990s, making Thwaites one of the fastest changing glaciers in Antarctica. However, the factors that cause this retreat are poorly understood.
The new data provide a clearer picture of the changes taking place under Thwaites, revealing that ice in crevasses above the glacier is melting rapidly. Melting in cracks and crevices is potentially dangerous because when water flows through them, heat and salt can be transferred to the ice. This can result in the expansion of these cracks, causing large tears in the ice shelf. However, fissures and fissures were not the only area of the shelf experiencing rapid melting.
While a layer of cold fresh water below the bottom of the ice shelf and above the underlying warm ocean slows the rate at which the flat parts of the ice shelf melt, the team was shocked to discover that melting above the bottom of the ice shelf has created a staircase-like formation. In these stepped areas, called terraces, Thwaites’ ice also melts quickly.
The melting of ice in these terraces, cracks and fissures may become important factors in the loss of ice from the Thwaites in the future, especially as large rifts cross the ice shelf. This means that these features could become the primary trigger for ice shelf collapse at Thwaites.
“These new ways of observing the glacier allow us to understand that it’s not just how much melting is happening, but how and where it’s happening that matters in these very warm parts of Antarctica,” said Cornell University researcher and Icefin team member Britney Schmid.
The research is published across the board two papers (opens in a new tab) both discussed in the journal Nature.
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