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Thwaite’s “doomsday glacier” is “holding by his fingernails,” scientists say

Thwaite's "doomsday glacier" is "holding by his fingernails," scientists say
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CNN

The so-called AntarcticaDoomsday Glacier” – nickname because of his high risk of collapse and threats to global sea levels — has the potential to retreat rapidly in the coming years, scientists say, adding to concerns about it extreme sea level rise that would accompany its eventual demise.

Thwaites Glacier, which can raise sea levels by several feet, is eroding along its underwater base as the planet warms. in the a study Scientists, published Monday in the journal Nature Geoscience, mapped the glacier’s historic retreat in hopes of learning from its past what the glacier is likely to do in the future.

They found that sometime in the last two centuries, the glacier’s base broke away from the sea floor, retreating at a rate of 2.1 kilometers per year. That’s double what scientists have observed in the past decade.

This rapid decay may have occurred “as late as the mid-20th century,” said Alastair Graham, the study’s lead author and a marine geophysicist at the University of South Florida, in a press release.

The floating ice edge at the edge of Thwaites Glacier in 2019.

It suggests that the Thwaites have the ability to retreat quickly in the near future once they retreat past a seafloor ridge that helps keep them in check.

“Thwaites is really holding on to its fingernails today, and we should expect big changes on small timescales going forward – even from one year to the next – as the glacier retreats over a flat ridge in its bed,” said Robert Larter, a Marine geophysicists and one of the study’s co-authors from the British Antarctic Survey said in the press release.

Rán, a Kongsberg HUGIN autonomous underwater vehicle, near Thwaites Glacier after a 20-hour mission mapping the seabed.

The US Antarctic Program research vessel Nathaniel B. Palmer works near the eastern Thwaites Ice Shelf in 2019.

Thwaites Glacier in West Antarctica is one of the widest on earth, larger than the state of Florida. But it’s only a fraction of the West Antarctic ice sheet, which NASA says contains enough ice to raise sea levels by as much as 16 feet.

As the climate crisis has accelerated, this region has been closely monitored for its rapid melting and capacity for widespread coastal destruction.

Thwaites Glacier itself has occupied scientists for decades. As early as 1973, researchers asked whether there was a high risk of collapse. Nearly a decade later, they found that because the glacier is grounded on a sea floor, not dry land, warm ocean currents could melt the glacier from below and destabilize it from below.

Because of this research, scientists began Calls the region around the Thwaites the “weak bottom of the West Antarctic Ice Sheet”.

A workboat recovering the Rán autonomous vehicle in one of the fjords of the Antarctic Peninsula during the 2019 Thwaites Glacier expedition.

In the 21st century, researchers began documenting the rapid retreat of the Thwaites in an alarming series of studies.

In 2001, satellite data showed that the ground line was receding at about 1 kilometer per year. In 2020, scientists found evidence of this indeed warm water flowed over the base of the glacier and melts it from below.

And then, in 2021, a study showed that the Thwaites Ice Shelf, which helps stabilize the glacier and prevent the ice from flowing freely into the ocean, could break within five years.

“We see from the satellite data that these large fractures are propagating across the ice shelf surface, essentially weakening the tissue of the ice; a bit like a crack in the windshield,” Peter Davis, an oceanographer with the British Antarctic Survey, told CNN in 2021. “It’s slowly spreading across the ice shelf and will eventually break up into a lot of different pieces.”

Monday’s results, which suggest the Thwaites are capable of retreating much faster than recently thought, were documented on a 20-hour mission in extreme conditions that mapped an underwater area the size of Houston, according to a news release.

Graham said that this research “was really a one-off mission,” but that the team hopes to return soon to collect samples from the seafloor so they can determine when the previous rapid retreats occurred. That could help scientists predict future changes to the “doomsday glacier,” which scientists had previously assumed would change only slowly — something Graham says this study disproves.

“Just a little kick for the Thwaites could result in a big reaction,” said Graham.

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