They found that at some point during the past two centuries, the base of the glacier has faded from the sea floor and retreated at a rate of 1.3 miles (2.1 kilometres) per year. That’s double the rate scientists have observed in the past decade or so.
This rapid disintegration may have occurred “as recently as the mid-20th century,” Alistair Graham, lead author of the study and a marine geophysicist at the University of South Florida, said in a press release.
He points out that Thwaites have the potential to undergo rapid decline in the near future, once they have retreated beyond a ridge on the sea floor helping to keep them in check.
“Thwaites is really sticking with its 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 retreats beyond a shallow ledge on its bottom,” said Robert Larter, a marine geophysicist and one of the study’s authors. Participants from the British Antarctic Survey, in the statement.
The Thwaites Glacier, located in West Antarctica, is one of the largest on Earth and larger than the state of Florida. But it’s just a faction of the West Antarctic ice sheet, which contains enough ice to raise sea level by as much as 16 feet, according to NASA.
With the acceleration of the climate crisis, this region has been closely watched due to its rapid melting and potential for widespread coastal destruction.
Thwaites Glacier itself has worried scientists for decades. As early as 1973, researchers wondered if it was at risk of collapse. After nearly a decade, they found that — because the glacier rests on the sea floor, rather than dry land — warm ocean currents can melt the glacier from below, destabilizing it from below.
In the 21st century, researchers began documenting Thwaites’ rapid decline in a troubling series of studies.
“From the satellite data, we see these large fractures spreading across the surface of the ice shelf, essentially weakening the texture of the ice; a bit like a windshield crack,” Peter Davis, oceanographer with the British Antarctic Survey, told CNN in 2021. “It slowly spreads across the ice shelf and eventually will break into a lot of different pieces.”
Monday’s findings, which indicate that Thwaites are able to recede much faster than recently thought, were documented on a 20-hour mission in extreme conditions that defined an underwater area the size of Houston, according to a press release.
This research was “truly a one-in-a-lifetime task,” Graham said, 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 in the “doomsday glacier,” which scientists previously assumed would be slow to undergo change — something Graham said this study refutes.
“Just a small kick to the buttocks can lead to a big response,” Graham said.