- Scientists got their first close-up look at what is eating away part of Antarctica’s Thwaites ice shelf, nicknamed the “doomsday glacier”.
- It is because of how much ice it has and how much seas would rise if it all melts.
- It’s both good and bad news.
Using a 13-foot pencil-shaped robot that swam under the grounding line where ice first just over the sea, scientists saw a shimmery critical point in Thwaites’ chaotic breakup, “where it’s melting so quickly, there’s just material streaming out of the glacier,” said robot creator and polar scientist Britney Schmidt of Cornell University.
Robotic Assistance
Before, scientists had no observations from this critical but hard-to-reach point on the Thwaites Glacier. But with the robot (named Icefin) lowered down a slender, 1,925-foot hole, they saw how important crevasses are in the fracturing of the ice, which takes the heaviest toll on the glacier, even more than melting. That’s how the glacier is falling apart. It’s not thinning and going away. It shatters,” said Schmidt, the lead author of one of two studies published.
That fracturing “potentially accelerates the overall demise of that ice shelf,” said Paul Cutler, the Thwaites program director for the National Science Foundation. The work comes out of a massive $50 million multiyear international research effort to better understand the Florida-sized glacier, which could make sea levels rise more than 2 feet if it melts, though that’s expected to take hundreds of years. At about 80 miles in width, the Thwaites Glacier is the widest on Earth. As the planet continues to warm, ice that composes the glacier is melting, like much of the sea ice that surrounds the Earth’s north and south poles. The glacier’s rapid changes have concerned scientists for years.
Researchers say the glacier is in a phase characterized by “rapid retreat,” or “collapse,” when a broader geological timeline is considered. A study conducted by marine physicist Alastair Graham at the University of South Florida last year suggested that, despite observations indicating the glacier’s melting rate had slowed down compared with previous evaluation periods, it would likely accelerate soon.
Rapidly Changing System
“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 the field three years ago,” said Oregon State University ice researcher Erin Pettit, who wasn’t involved in either study. “I am definitely expecting the rapid change to continue and accelerate over the next few years.” Pennsylvania State University glaciologist Richard Alley, who also wasn’t part of the studies, said the new work “gives us an important look at processes affecting the crevasses that might eventually break and cause loss of much of the ice shelf.”
Davis said the melting isn’t nearly the problem. The more the glacier breaks up or retreats, the more ice floats in water. When ice is on ground as part of the glacier, it isn’t part of sea rise, but when it breaks off land and then goes onto water, it adds to the overall water level by displacement, just as ice added to a glass of water raises water level. The key to seeing exactly how bad conditions are on the glacier would require going to the main trunk and looking at the melting from below. But that would require a helicopter to land on the ice instead of a heavier airplane and would be incredibly difficult, said Eric Rignot of the University of California Irvine.
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Source: Cbsnews
