Robot reveals clues behind what’s feeding on Antarctica’s ‘doomsday glacier’

Scientists have seen up close what is consuming part of Antarctica for the first time Thwaite’s Ice Shelfnicknamed the “doomsday glacier” because of how much ice it has and how much seas could rise if it all melts – and that’s both good news and bad news.

Using a 13-foot pencil-shaped robot that swam below the baseline, where the ice first juts out over the sea, scientists saw a glimmering critical point in Thwaites’ chaotic resolution, “where it’s melting so fast, material just flows out of the glacier.” said robot creator and polar explorer Britney Schmidt of Cornell University.

Previously, scientists had no observations from this critical but elusive point on Thwaites Glacier. But when the robot (named Icefin) was lowered into a narrow, 1,925-foot hole, they saw how important fissures are in breaking the ice that takes the greatest toll on glaciers, even more so than melting.

“That’s how the glacier breaks apart. It’s not thinning and disappearing. It’s breaking up,” said Schmidt, the lead author of one of two studies published Wednesday in the journal Nature.

That breach “potentially accelerates the general sinking of this ice shelf,” said Paul Cutler, the National Science Foundation’s Thwaites program director, who returned from the ice last week. “The ultimate mode of failure can be that it falls apart.”

The work is the result of a massive multi-year, $50 million international research effort to better understand this Florida-sized glacierswhich could raise sea levels by more than 2 feet if it melts, although that’s expected to take hundreds of years.

At about 80 miles wide, Thwaites Glacier is the widest on earth. As the planet continues to warm, the ice that makes up the glacier is melting, as is much of the sea ice that surrounds Earth’s north and south poles. The rapid changes in the glacier have occupied scientists for years.

Researchers say the glacier is in a phase characterized by “rapid retreat” or “collapse” when viewed over a broader geologic timeline. A study conducted last year by marine physicist Alastair Graham at the University of South Florida suggested that the glacier’s melting rate is likely to be accelerating soon, despite observations suggesting it has been slowing compared to previous assessment periods.

“Similar rapid pullback pulses are likely to occur in the near future,” the study said.

Thwaites’ melting is dominated by what’s happening below, where warmer water nibbles at the bottom, called basal melting, said Peter Davis, an oceanographer at British Antarctic Survey, who is a lead author of one of the studies.

“Thwaites is a rapidly changing system, much faster than when we started our work five years ago and even since we were in the field three years ago,” said Oregon State University ice researcher Erin Pettit, who was not involved in either study. “I definitely assume that the rapid change will continue and accelerate in the coming years.”

Pennsylvania State University glaciologist Richard Alley, who was also not involved in the studies, said the new work “gives us an important insight into processes affecting the crevasses that could eventually rupture and lose much of the ice shelf.”

Now for the good news: much of the shallow underwater area the scientists have been exploring is melting much more slowly than expected.

But that doesn’t really change how much ice is coming from the land portion of the glacier and raising sea levels, Davis said.

Davis said melting is far from the problem. The more the glacier breaks up or retreats, the more ice floats in the water. When ice is on the ground as part of the glacier it is not part of sea level, but when it breaks off land and then enters the water it contributes to the total water level by displacement, just like ice added to a glass increases water the water level.

And more bad news: The new research comes from the eastern, larger and more stable part of Thwaites. The researchers were unable to safely land a plane and drilled a hole in the ice in the main stem, which breaks up much faster.

The key to seeing exactly how bad conditions are on the glacier would be to go to the main stem and look at the melting from below. But that would require a helicopter to land on the ice instead of a heavier plane, and that would be incredibly difficult, said Eric Rignot of the University of California Irvine.

The glacial surface of the main trunk “is so jumbled with crevasses that it almost looks like a row of sugar cubes. There’s no place to land a plane,” NSF’s Cutler said.

Ted Scambos of the National Snow and Ice Data Center said the recent results are helping to understand how Thwaites is declining.

“Unfortunately, this will still be a big problem a century from now,” Scambos said in an email. “But our better understanding gives us some time to take action to slow sea-level rise.”

As the skinny robot made its way through the hole in the ice – created by a jet of hot water – the cameras showed not only the meltwater, but also the crucial crevasses and the sea floor. It also featured critters, particularly sea anemones, swimming beneath the ice.

“It was really, really cool to find them by accident in this environment,” Schmidt said in an interview. “We were so tired it kind of makes you wonder, ‘Am I really seeing what I’m seeing?'”

“In the background are all these twinkling stars, which are like rocks and sediment and things that have been picked up by the glacier,” Schmidt said. “And then the anemones. It’s really a wild experience.”