They found that at some point in the last two centuries, the base of the glacier broke away from the sea floor and retreated at a rate of 1.3 miles (2.1 kilometers) per year. This is twice as much as scientists have observed in the last decade.
Alastair Graham, the study’s lead author and a marine geophysicist at the University of South Florida, said this rapid break-up “happened in the middle of the 20th century.”
This suggests that Thwaites has the ability to retreat rapidly in the near future once the seafloor retreats past the ridge that helps keep it in check.
“Thwaites is really holding on today, and once the glacier retreats to the edge of the shallow ridge in its bed, we should expect to see big changes on small time scales in the future,” he said. Larter, a marine geophysicist and one of the co-authors of the British Antarctic Survey, said in a statement.
Thwaites Glacier, located in West Antarctica, is one of the largest glaciers on Earth and is larger than the state of Florida. But that’s just part of the West Antarctic Ice Sheet, which holds enough ice to raise sea levels by 16 feet, according to NASA.
As the climate crisis accelerates, the region is being watched closely for its ability to rapidly melt and destroy vast coastlines.
Thwaites Glacier itself has puzzled scientists for decades. As early as 1973, researchers were questioning whether it was at high risk of collapse. About a decade later, they found that — because the glacier rests on the seafloor, not dry land — warm ocean currents can melt the glacier from below, destabilizing it from below.
In the 21st century, researchers began to document Thwaites’ rapid retreat in an alarming series of studies.
“From the satellite data, we see that these large fractures that spread across the surface of the ice shelf significantly weaken the texture of the ice; a bit like a windshield crack,” said Peter Davis, an oceanographer at the British Antarctic Survey. CNN in 2021. “It’s slowly spreading across the ice shelf and will eventually break up into many different pieces.”
Monday’s findings, which show that Thwaites is capable of retreating at a faster rate than recently thought, were documented during a 20-hour mission in extreme conditions that mapped an underwater area the size of Houston, according to a news release.
Graham said the study is “really a once-in-a-lifetime mission,” but the team hopes to return soon to collect samples from the seafloor, 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 undergo change — something Graham said the study disproves.
“A small blow to Thwaites can cause a big reaction,” Graham said.
