Skinny robot documents forces eroding Doomsday Glacier

Scientists got ir first up-close look at what’s eating away part of Antarctica’s Thwaites ice shelf, nicknamed  Doomsday Glacier because of its massive melt and sea rise potential, and it’s both good and bad news.

Using a 13-foot pencil-shaped robot that swam under grounding line where ice first juts over sea, scientists saw a shimmery critical point in Thwaites’ chaotic breakup, “where it’s melting so quickly re, re’s just material streaming out of glacier,” said robot creator and polar scientist Britney Schmidt of Cornell University. 

Before, scientists had observations from this critical but hard-to-reach point on Thwaites. But with robot named Icefin lowered down a slender 1,925-foot (587-meter) hole, y saw how important crevasses are in fracturing of ice, which takes heaviest toll on glacier, even more than melting. “That’s how glacier is falling apart. It’s t thinning and going away. It shatters,” said Schmidt, lead author of one of two studies in Wednesday’s journal Nature.

That fracturing “potentially accelerates overall demise of that ice shelf,” said Paul Cutler, Thwaites program director for National Science Foundation who returned from ice last week. “It’s eventual mode of failure may be through falling apart.”

work comes out of a massive $50 million multi-year international research effort to better understand widest glacier in world.  Florida-sized glacier has gotten nickname “Doomsday Glacier” because of how much ice it has and how much seas could rise if it all melts — more than 2 feet (65 centimeters), though that’s expected take hundreds of years. 

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

“Thwaites is a rapidly changing system, much more rapidly changing than when we started this work five years ago and even since we were in field three years ago,” said Oregon State University ice researcher Erin Pettit, who wasn’t part of eir study. “I am definitely expecting rapid change to continue and accelerate over next few years.”

Pennsylvania State University glaciologist Richard Alley, who also wasn’t part of studies, said new work “gives us an important look at processes affecting crevasses that might eventually break and cause loss of much of ice shelf.”

good news: Much of flat underwater area y explored is melting much slower than y expected. bad news: That doesn’t really change how much ice is coming off land part of glacier and driving up sea levels, Davis said.

Davis said melting isn’t nearly problem at Thwaites that glacier retreat is. more glacier breaks up or retreats, more ice floats in water. When ice is on ground as part of glacier it isn’t part of sea rise, but when it breaks off land and n goes onto water it adds to overall water level by displacement, just as ice added to a glass of water raises water level.

And more bad news: This is from eastern, larger and more stable part of Thwaites. Researchers couldn’t safely land a plane and drill a hole in ice in main trunk, which is breaking up much faster. And y also found staircase-like steps, those crevasses, in parts of more stable eastern side where break-up is far faster and worse.

key to seeing exactly how bad conditions are on glacier would require going to main trunk and looking at melting from below. But that would require a helicopter to land on ice instead of a heavier airplane and would be incredibly difficult, said studies co-author Eric Rigt of University of California Irvine.

main trunk’s glacier surface “is so messed up by crevasses it looks like a set of sugar cubes almost. re’s place to land a plane,” NSF’s Cutler said.

Ted Scambos of National Sw and Ice Data Center, who wasn’t part of studies, said results add to understanding how Thwaites is diminishing. 

“Unfortunately, this is still going to be a major issue a century from w,” Scambos said in an email. “But our better understanding gives us some time to take action to slow pace of sea level rise.”

When skinny robot wended its way through hole in ice – made by a jet of hot water – cameras showed t just melting water, crucial crevasses and seabed. It showed critters, especially sea anemones, swimming under ice. 

“To accidentally find m here in this environment was really, really cool,” Schmidt said in an interview. “We were so tired that you kind of wonder like, ‘am I really seeing what I’m seeing?’ You kw because re are se little creepy alien guys ( anemones) hanging out on ice-ocean interface. 

“In background is like all se sparkling stars that are like rocks and sediment and things that were picked up from glacier,” Schmidt said. “And n anemones. It’s really kind of a wild experience.”