Taking advantage of rare ice-free waters in West Antarctica last February, scientists got their first look underneath Thwaites Glacier, a massive and increasingly unstable formation perched at the edge of the continent. What they saw only increased fears of a collapse that could raise global sea levels by more than half a meter. Data gathered by a robotic submarine deployed by scientists with the International Thwaites Glacier Collaboration suggest that warm water from the deep ocean is welling up from three directions and mixing underneath the ice.
“Thwaites has got these three guns pointed right at it,” says Erin Pettit, a glaciologist at Oregon State University in Corvallis and a co-leader of the five-year, US$50-million project to assess the glacier’s stability. “There is warm water coming from all directions.” She presented initial results from the first two years of the project this week at the American Geophysical Union’s ocean science meeting in San Diego, California.
The warm currents could further destabilize the glacier, which is as large as the island of Great Britain and holds enough ice to boost global sea levels by an estimated 65 centimeters (see ‘A precarious position’). If it collapses, Thwaites could take other parts of the western Antarctic ice sheet with it and become the single largest driver of sea-level rise this century.