Thwaites’ ‘apocalyptic glacier’ holds ‘by its fingernails’, scientists say

The Thwaites Glacier, capable of raising sea levels by several feet, is eroding along its undersea 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 over the past two centuries, the base of the glacier had broken away from the seabed and retreated at a rate of 2.1 kilometers per year. This is double the rate observed by scientists over the past decade.

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

This suggests that the Thwaites has the ability to undergo a rapid retreat in the near future, once it has moved away from a seabed ridge that helps keep it in check.

“Thwaites is really hanging on to his nails today, and we should expect to see big changes on small time scales in the future – even from year to year – once the glacier settles. will retreat past 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.

Rán, a Kongsberg HUGIN autonomous underwater vehicle, near Thwaites Glacier after a 20-hour seabed mapping mission.
The US Antarctic Program research vessel Nathaniel B. Palmer working near the Eastern Thwaites Ice Shelf in 2019.

The Thwaites Glacier, located in West Antarctica, is one of the largest on the planet and is larger than the state of Florida. But that’s just one faction of the West Antarctic Ice Sheet, which contains enough ice to raise sea levels up to 16 feet, according to NASA.

With the climate crisis accelerating, this region has been closely watched due to its rapid melting and capacity for widespread coastal destruction.

The Thwaites Glacier itself has preoccupied scientists for decades. As early as 1973, researchers wondered if it presented a high risk of collapse. Nearly a decade later, they discovered that – because the glacier is anchored to a seabed rather than dry land – warm ocean currents could melt the glacier from below, destabilizing it from below.

It was through this research that scientists began calling the region around the Thwaites the “Weak Underbelly of the West Antarctic Ice Sheet”.
A workboat retrieving the Rán autonomous vehicle from one of the Antarctic Peninsula's fjords during the 2019 Thwaites Glacier expedition.

In the 21st century, scholars began documenting the rapid retreat of the Thwaites in a series of alarming 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 hot water was indeed flowing at the base of the glacier, melting it from below.
World's largest ice cap is collapsing faster than previously thought, satellite imagery shows
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 break in five years.

“From satellite data, we see these large fractures propagating across the surface of the pack ice, essentially weakening the ice fabric; a bit like a crack in a windshield,” said British Antarctic oceanographer Peter Davis. Survey. CNN in 2021. “It spreads slowly over the sea ice and eventually fractures into many different pieces.”

Monday’s findings, which suggest the Thwaites is capable of retreating at a much faster rate than recently thought, were documented during a 20-hour mission in extreme conditions that mapped an area under Houston-sized navy, according to a press release.

Graham said this search “was truly a once-in-a-lifetime mission”, but the team hopes to return soon to collect seafloor samples so they can determine when previous rapid retreats occurred. This could help scientists predict future changes to the “doomsday glacier”, which scientists had previously assumed would be slow to change – something Graham said this study disproves.

“Just a little kick to the Thwaites could lead to a big response,” Graham said.

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