Antarctica's Doomsday Glacier Is Close to Becoming Unhinged

 


There’s nothing like sitting through a series of presentations about all the ways one of the most imperiled glaciers on Earth to get the blood flowing.

The American Geophysical Union’s annual meeting kicked off with a splash of news about Thwaites Glacier. If there’s one Antarctic glacier you need to care about, it’s this one. (Though, really why choose one?) Dubbed the “Doomsday Glacier,” Thwaites is in extremely rough shape and a key portion of it could lose its grip on the bedrock by the end of this decade. That, in case it’s not clear, is bad.

“We’re watching a world do things we haven’t seen before,” Ted Scambos, a senior research scientist at the Cooperative Institute for Research in Environmental Science, said on a press call.

What’s happening to Thwaites Glacier is a disaster of epic proportions, and researchers have been racing to chronicle it. The glacier spills down from the West Antarctic ice sheet and extends over the Amundsen Sea. To get a grasp on what’s happening at Thwaites, researchers have undertaken a multi-year study that probes the glacier from above and below and even uses satellites to gauge just what’s going on.

The results have been ominous. The scientists said their measurements show parts of the floating ice shelf are receding at a rate of 1.2 miles (2 kilometers) per year. “It’s a bit unsettling, Scambos said, especially standing on the ice looking at the ice sheet. The horizon is moving at you a mile a year.”


Warm water has also penetrated deep underneath the glacier. That’s resulted in strange deformities in parts of the ice, including large crevasses cutting up into the ice. There’s one particularly beat-up area that Lizzy Clyne, a researcher at Lewis & Clark College who has studied the glacier, said used to be attached to the bedrock a decade ago but is now a huge cavity.

As warm water penetrates deeper under the ice, it means there’s less of it holding fast to solid ground. That can lead to more fracturing and cracking, and, eventually, have the entire ice shelf collapse. That would allow more ice to tumble into the sea. Erin Pettit, a scientist at Oregon State University, said that one of the more stable areas where Thwaites is grounded on bedrock is undergoing rapid changes that “will reduce down to near zero contact by the end of the decade.” It was a location she had chosen to study on the eastern side of the ice because it was one of the “most boring parts” of the glacier. However, satellite images before a field season out there revealed a crack spreading across the face of the ice, one which she worried could cut across their field site. Ultimately, that wasn’t an issue—but it was still an ominous sign of the state of Thwaites.

Pettit likened it to a car windshield with a few cracks. “Then you go over a bump and it causes it to shatter,” she said.

But while you can replace a windshield, there’s no repair service for ice. The floating part of the glacier holds back a basin of land ice that, if dumped in the ocean, would unleash roughly 10 feet (3 meters) of sea-level rise. That won’t come all at once if the ice shelf becomes unmoored. But the collapse of Thwaites would set the world on a dangerous trajectory in the decades and even centuries to come. Whether we’re on that trajectory or not is something the researchers will continue to probe. But the state of things right now is still worrisome.

“There’s going to be a dramatic change to the front of the glacier within less than a decade,” Scambos said. “When that happens, the fast-flow part of Thwaites is likely to widen because bracing on [the] east side may be gone. It may still take a few decades before some of the other processes … [but] it will effectively widen the dangerous part of the glacier.”

gizmodo.com

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