The Doomsday Glacier in Antarctica is melting faster than scientists thought

Antarctica’s “doomsday glacier”, referred to as such for its potential to dramatically raise global sea levels, is melting faster than we thought thanks to warmer sea water passing below it, according to a new study. The researchers, led by glaciologists with the University of California, Irvine (UCI), said in a study published Monday in the Proceedings of the National Academy of Sciences that the Thwaites Glacier may be breaking apart “much faster” than previously believed. The glacier has gotten its nickname because of how much ice it has and how much seas could rise if it all melts — more than two feet over hundreds of years.

Thwaites is on Antarctica’s western half, east of the jutting Antarctic Peninsula, which used to be the area scientists worried most about. For years, experts have worried about the possible demise of the Thwaites, whether by ocean water melting it from below, the glacier unmooring from its attachment to the seabed, or the ice mass cracking and breaking apart. Using satellites and a technique called radar interferometry to track changes in surface elevation, the team found that the glacier appeared to be lifting several centimeters as pressurized tide water moved below it across many miles, further inland than previously thought.

There are places where the water is almost at the pressure of the overlying ice, so just a little more pressure is needed to push up the ice. The water is then squeezed enough to jack up a column of more than half a mile of ice. Warmer seawater working its way under the glacier may help explain the rapid, past, and present changes in ice sheet mass and the slower changes replicated by ice sheet models.

Pressurized seawater will create a “vigorous melt” that will further imperil the glacier.

Thwaites is the most unstable place in the Antarctic and contains the equivalent of 60 centimeters of sea level rise. The worry is that we are underestimating the speed that the glacier is changing, which would be devastating for coastal communities around the world. It is still not clear how much time is left before the ocean water’s damage to the glacier is irreversible, but hopefully the discovery will lead to more accurate models.

It will take many decades, not centuries, for the Thwaites to fully melt. Part of the answer also depends on whether our climate keeps getting warmer or not, which depends completely on us and how we manage the planet. And for the first time, there is visible evidence that shows warm seawater pumping underneath the glacier. The Thwaites, part of the vast West Antarctic Ice Sheet, is one of the world’s fastest-changing and most unstable glaciers.

It has been studied for years as an indicator of human-caused climate change. Study results also suggest the Antarctic Ice Sheet is more vulnerable to a warming ocean than previously thought, and, worryingly, may require a reassessment of sea-level rise projections. To conduct the study, scientists used high-resolution satellite radar data to find evidence of the intrusion of warm, high-pressure seawater many miles beneath the grounded ice of Thwaites.

There is much more seawater flowing into the glacier than had been previously thought.

These intrusions make the glacier more sensitive to ocean warming, and more likely to fall apart as the ocean gets warmer. Future projections of global sea-level rise will have to include this new data. The projections will go up. As it melts, Thwaites could cause ocean levels to rise as much as 2 feet. But the glacier is also a natural dam to other ice in West Antarctica.

If that ice is released into the oceans, levels could rise 10 feet. Such a rise would put many of the world’s coastal cities underwater. It will gravely impact populations in many low-lying areas like Vancouver, Florida, Bangladesh, and low-lying Pacific islands, such as Tuvalu and the Marshall Islands.