Roughly measuring the size of Florida, the Thwaites Glacier is one of the most rapidly melting ice formations in Antarctica, having retreated more than eight miles since the 1990s. Scientists refer to it as the “doomsday glacier” due to concerns about its collapse, which could raise global sea levels by more than a meter, causing devastation along coastal cities and communities. 

According to two papers published in the journal Nature, researchers are learning more about the driving forces behind the glacier’s rapid retreat, thanks in part to a robot deployed through a 600-meter-deep borehole in the glacier. Although melting has increased beneath the ice shelf, the current melt rate is slower than many computer models had estimated. A layer of fresh water between the bottom of the ice shelf and the ocean below slows the rate of melting along flat parts of the shelf. 

Scientists discovered that the melting had produced a stepped topography across the bottom of the ice shelf, resembling a staircase, as well as cracks in the ice where rapid melting was taking place. “Our results are a surprise, but the glacier is still in trouble,” says Dr. Peter Davis, oceanographer at the British Antarctic Survey and lead author of one of the papers.