The calls of Antarcticaend of the world glacier” – nicknamed for his high risk of collapse and threat to global sea levels – has the potential to recede rapidly in coming years, scientists say, amplifying concerns about the extreme sea level rise that would accompany its possible disappearance.
The Thwaites Glacier, capable of raising sea levels several feet, is eroding along its underwater base as the planet warms. In A study Published Monday in the journal Nature Geoscience, scientists mapped the glacier’s historical retreat, hoping to learn from its past what the glacier is likely to do in the future.
They found that at some point in the last two centuries, the base of the glacier broke away from the seabed and retreated at a rate of 1.3 miles (2.1 kilometers) per year. That’s double the rate scientists have observed in the last decade or so.
That rapid disintegration possibly occurred “in the middle of the 20th century,” Alastair Graham, lead author of the study and a marine geophysicist at the University of South Florida, said in a news release.
It suggests that Thwaites has the ability to rapidly retreat in the near future, once he recedes past a seafloor ridge that is helping to keep him in check.
“Thwaites is really holding on with his fingernails, and we should expect to see big changes on small timescales in the future, even from one year to the next, once the glacier recedes beyond a shallow ridge in its bed,” Robert Larter, a marine geophysicist and one of the study’s co-authors from the British Antarctic Survey, said in the statement.
Thwaites Glacier, located in West Antarctica, is one of the widest on Earth and is larger than the state of Florida. But it’s only a fraction of the West Antarctic Ice Sheet, which contains enough ice to raise sea levels up to 16 feet, according to NASA.
As the climate crisis has accelerated, this region has been closely monitored due to its rapid melting and capacity for widespread coastal destruction.
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Thwaites Glacier itself has worried scientists for decades. As early as 1973, researchers questioned whether he was at high risk of collapse. Nearly a decade later, they found that because the glacier is grounded on the seafloor, rather than dry land, warm ocean currents could melt the glacier from below, causing it to destabilize from below.
It was because of that research that scientists began calling the region around Thwaites the “weak belly of the West Antarctic Ice Sheet”.
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 grounding line was receding about 0.6 miles (1 kilometer) per year. In 2020, scientists found evidence that in fact, the warm water flowed through the base of the glacier, melting it from below.
And then in 2021, a study showed the Thwaites Ice Shelf, which helps stabilize the glacier and prevent ice from flowing freely into the ocean. could be broken in five years.
“From satellite data, we’re seeing these large fractures spreading across the surface of the ice shelf, essentially weakening the structure of the ice; kind of 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 fracture into many different pieces.”
Monday’s findings, which suggest Thwaites is capable of receding at a much faster rate 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 statement. of press.
Graham said this investigation “was truly a once-in-a-lifetime mission,” but that the team hopes to return soon to collect samples from the seafloor so they can determine when earlier rapid withdrawals occurred. That could help scientists predict future changes to the “doomsday glacier,” which scientists had previously assumed would take time to change, something Graham says this study refutes.
“Just a little kick to the Thwaites could spark a big response,” Graham said.
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