Scientists predict that surprising formations under the ice shelf of 'Doomsday Glacier' could increase the rate of melting and rise in sea level.
The Thwaites Glacier, located in West Antarctica, has been nicknamed the "Doomsday Glacier" due to the catastrophic sea level rise it could cause if it were to collapse. The ice shelf acts as a cork, keeping the glacier in place and providing an important buffer against sea level rise. But the ice shelf is highly vulnerable to the warming ocean, and two new studies published in Nature reveal that while the pace of melting underneath much of the ice shelf is slower than previously thought, the deep cracks and "staircase" formations in the ice are melting much faster.
Every year, the Thwaites Glacier sheds billions of tons of ice into the ocean, contributing about 4% of the annual sea level rise. The point where the glacier meets the seafloor has retreated nearly 9 miles (14 kilometers) since the late 1990s, exposing more ice to relatively warm ocean water. Scientists have estimated that if the Thwaites completely collapsed, the global sea level could rise around 10 feet, reports The Conversation
To better understand the reshaping of the remote coastline, a US and British team of 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 (600 meters) deep into the ice and sent down various instruments to take measurements from the glacier. One of these instruments was a torpedo-like robot called Icefin, which allowed them access to areas that were previously almost impossible to survey.
The results of the research revealed a complex picture of how the Thwaites Glacier is changing. While its collapse could take hundreds or thousands of years, it could also happen much sooner, triggering an unstable and potentially irreversible retreat of the glacier. The complete collapse of the Thwaites could lead to a sea level rise of more than 2 feet (70 centimeters). Coastal communities around the world could be devastated by the effects of such a rise, making it even more crucial for scientists to understand the glacier's rapid transformation.
Scientists recently studied the Thwaites Glacier in Antarctica and discovered two shocking findings. The first was that the rate of melting beneath much of the flat part of the ice shelf was lower than expected – averaging between 2 and 5.4 meters a year. The second finding was an underwater glacial landscape much more complex than expected, dominated by strange staircase-like terraces and crevasses. Melting was particularly rapid in these areas.
The research team was able to conclude that melting was being suppressed by a layer of colder, fresher water at the base of the glacier between the ice shelf and the ocean. They also determined that warm, salty water was funneling through and widening cracks and crevasses, contributing to instabilities in the glacier. This melting along the sloped ice of the cracks and terraces may become the primary trigger for ice shelf collapse.
The study provides “the missing pieces” to work out exactly how this change is happening. It also offers “novel insights into how rapidly the bottom of the ice shelf is melting and the mechanisms by which it’s melting” which are very important for improving our understanding and ability to model how Thwaites will change in the future. The findings add a new layer to a slew of alarming studies pointing to the glacier’s rapid melting and the potential for a rapid retreat in the coming years.
The research, while still indicating that the glacier is in trouble, can also help make more accurate projections about sea level rise, which can be fed into efforts to mitigate climate change and protect coastal communities. The scientists hope that the research will prompt people to “sit up and take notice” of the changes that are occurring, as the consequences of what happens on Thwaites will impact everybody.