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Antarctica’s “Doomsday Glacier,” also known as the Thwaites Glacier, has been a cause for concern among scientists for years, and new research has now revealed unexpected changes that could lead to catastrophic sea level rise.
The Thwaites Glacier is a massive ice sheet located in West Antarctica, roughly the size of Florida. It is held in place by an ice shelf that juts out onto the surface of the ocean, acting like a cork and providing an important defense against sea level rise. But as the ocean warms, the ice shelf is becoming highly vulnerable.
Two recent studies published in the journal Nature have shed light on the ways in which the Thwaites Glacier is rapidly changing. While the pace of melting underneath much of the ice shelf is slower than previously thought, deep cracks and “staircase” formations in the ice are melting much faster than expected. The melting happens at the point where the glacier meets the seafloor, which has retreated nearly nine miles since the late 1990s, exposing a larger slice of ice to relatively warm ocean water.
The Thwaites Glacier is shedding billions of tons of ice into the ocean every year, contributing about 4% of annual sea level rise. The complete collapse of the glacier could lead to sea level rise of more than two feet, which would be enough to devastate coastal communities around the world. Additionally, the Thwaites is acting like a natural dam to the surrounding ice in West Antarctica, and scientists have estimated global sea level could ultimately rise around 10 feet if the Thwaites collapsed.
To better understand the changes happening at the Thwaites Glacier, a team of US and British scientists from the International Thwaites Glacier Collaboration traveled to the glacier in late 2019. Using a hot water drill, they bored a hole nearly 2,000 feet deep into the ice and sent down various instruments to take measurements from the glacier over a five-day period. The instruments included a torpedo-like robot called Icefin, which allowed them access to areas previously almost impossible to survey.
The scientists discovered an underwater glacial landscape much more complex than expected, dominated by strange staircaselike terraces and crevasses — big cracks going all the way through the ice shelf. Melting was particularly rapid in these areas, with warm, salty water funneling through and widening cracks and crevasses, contributing to instabilities in the glacier.
“The glacier is not just melting up, but it’s melting out,” said Britney Schmidt, an associate professor at Cornell University and a lead author on one of the papers.
Melting along the sloped ice of the cracks and terraces “may become the primary trigger for ice shelf collapse,” according to the studies’ authors.
While the Thwaites Glacier is receding, the rate of melting beneath much of the flat part of the ice shelf is lower than expected, with a melt rate averaging 2 to 5.4 meters a year, according to the study. Melting is being suppressed by a layer of colder, fresher water at the base of the glacier, between the ice shelf and the ocean, according to the research.
“The glacier is still in trouble,” said Peter Davis, an oceanographer at the British Antarctic Survey and a lead author on the other paper. “What we have found is that despite small amounts of melting, there is still rapid glacier retreat, so it seems that it doesn’t take a lot to push the glacier out of balance.”
The research can help make more accurate projections about sea level rise, which can be fed into efforts to mitigate climate change and protect coastal communities. However, David Rounce, a glaciologist at Carnegie Mellon University who was not involved in the study, noted that the new research offers “novel insights into the complex dynamics of the Thwaites Glacier,” but there is still much to learn about the ice sheet.
Scientists continue to study the Thwaites Glacier using various tools, including satellite imagery, radar, and computer models. The International Thwaites Glacier Collaboration plans to return to the glacier in the coming years to gather more data and investigate the glacial landscape further.
The Thwaites Glacier is just one of many melting ice sheets contributing to sea level rise around the world. As global temperatures continue to warm due to human-caused greenhouse gas emissions, the rate of ice melt is accelerating, and the impacts of sea level rise are being felt in coastal communities around the world.
The threat of catastrophic sea level rise is one of the many reasons why urgent action is needed to address climate change. Governments, businesses, and individuals must work together to reduce greenhouse gas emissions, transition to clean energy sources, and implement policies and practices that protect vulnerable communities from the impacts of climate change.
The Thwaites Glacier may seem like a remote and distant problem, but its collapse could have far-reaching consequences for the planet. By taking action to address climate change now, we can help protect the Thwaites Glacier and the countless other natural wonders that make our planet unique and beautiful.