One of Antarctica’s Biggest Glaciers Is Eroding Faster Than Thought
Climate change is going to make one of Antarctica’s biggest glaciers unstable over the coming years, which could lead to it contributing much more to global sea-level rise than previously realized.
According to a study published this week in Nature, East Antarctica’s Totten Glacier could cross an irreversible threshold within the next century. Researchers predict that by that point, the glacier will withdraw more than 180 miles inland, releasing so much water in the process that it could cause a rise in global sea levels of up to 9.5 feet.
The news follows two previous studies on the Totten Glacier. The first, published in March 2015, found that the glacier was thinning because of warm ocean waters. The second, published last October, confirmed that finding and concluded that the glacier was retreating, although not as fast as the most commonly studied glaciers in West Antarctica.
The new study used radar, magnetic, and gravity measurements to understand what is happening beneath the surface of Totten Glacier. Researchers found a history of erosion caused by glacial advances and retreats over the millennia. With this evidence in hand, they concluded that further retreat over the next century could make Totten fundamentally unstable. If it crossed that point, the scientists warned, further retreat could become irreversible.
Lead author Alan Aitken of the University of Western Australia, who also contributed to the March 2015 study, said the results of the new study were not what was expected. “Although our work evolved gradually over months, I was very surprised to see the deeply eroded inland area, as my initial hypothesis was that this would not be so deeply affected by erosion,” he said. “This result was a real mind-opener as to how such a large glacier might show fairly rapid change with attendant influences on global sea level.”
Eric Rignot of the University of California, Irvine, and NASA’s Jet Propulsion Laboratory, who was part of last October’s study but not affiliated with the new research, said Aitken’s research adds to the understanding of sea-level rise and not in a good way. “The traditional view that only West Antarctica is at risk needs to be revised,” he said, adding that most projections of sea-level rise ignore the impact of melting in East Antarctica. That means that most current models may underestimate the worldwide risk. “The Wilkes Land sector of East Antarctica is also vulnerable, and it holds far more ice altogether than West Antarctica,” he said.
Rignot led a study in 2014 that found that melting in East Antarctica could contribute to global sea-level rise by four feet. That now appears to be just one part of the bigger picture.
He pointed out that the warm waters driving the Totten Glacier retreat are an issue because the southernmost continent is “not warming as fast as the rest of the world, and the ozone hole is cooling Antarctica.”
Aitken said that researchers are continuing to study Totten and hope to resolve questions about how past changes may offer additional clarity into how it will respond to future change. One of the most important things to resolve, he said, is how melting along Antarctica’s coast may cause large-scale glacial retreats such as the one identified in the new paper. Researchers also hope to look at offshore sediment to provide a better understanding of the timing and rate of past collapses.