They found that at some point in the past two centuries, the base of the glacier had moved away from the seafloor, retreating at a rate of 1.3 miles (2.1 kilometers) per year. That’s more than twice the rate scientists observed in the past decade.
That rapid decay “probably occurred in the mid-20th century,” Alastair Graham, the study’s lead author and a marine geophysicist at the University of South Florida, said in a news release.
That suggests that thwaites have the ability to quickly retreat in the future, once it passes a seafloor ridge, helping to keep it under control.
“Thwaites is really holding on today by its fingernails, and we should expect big changes on small timescales in the future — from one year to the next — as the glacier recedes beyond a shallow ridge in its bed,” said Robert Larder, a marine geophysicist with the British Antarctic Survey. from one of the study’s co-authors said in the release.
Thwaites Glacier, located in West Antarctica, is the widest on Earth and larger than the state of Florida. But that’s just one section of the West Antarctic Ice Sheet, which contains enough ice to raise sea levels by up to 16 feet, according to NASA.
As the climate crisis accelerates, the region is being watched closely because of its potential for rapid melting and widespread coastal destruction.
Thwaites Glacier has worried scientists for decades. As early as 1973, researchers questioned whether it was in danger of collapsing. Nearly a decade later, they found that — as the glacier lands on a seafloor instead of dry land — warm ocean currents melt the glacier from beneath, disrupting it from below.
In the 21st century, researchers began documenting Thwaites’ rapid retreat in an alarming series of studies.
“From the satellite data, we see these large fractures spreading across the surface of the ice sheet, essentially weakening the fabric of the ice; it’s like a windscreen crack,” said Peter Davies, an oceanographer at the British Antarctic Survey. CNN in 2021. “It slowly spreads across the ice sheet, and eventually it breaks up into different pieces.”
Monday’s findings suggest that the thwaites are capable of retreating much faster than recently thought, according to a news release, documenting a 20-hour mission under extreme conditions that mapped an underwater region.
Graham said the research is “really once in a lifetime,” but the team hopes to soon collect samples from the ocean floor so they can determine when previous rapid retreats occurred. That could help scientists predict future changes in the “doomsday glacier,” which scientists previously thought would be slow to undergo change — something Graham said the study rejects.
“A little kick to the thwaites can lead to a big response,” Graham said.