“We don’t know how much the ice sheet beneath it is going to melt,” she says. But her team found grim results when they tried to model what might happen. “No matter what scenario we threw at it, Thwaites collapsed,” Medley says.
Scientists aren’t sure how long that will take, and the uncertainty has turned new attention to Thwaites. A deep, narrow trough helps constrain Pine Island Glacier. Thwaites isn’t so lucky. The glacier will widen as it retreats deeper inland. Medley says this geometry means Thwaites will also start to draw more stable ice from neighboring glaciers.
A $25 million expedition next year, funded by the National Science Foundation and the United Kingdom’s Natural Environment Research Council, will collect data on Thwaites that might offer a better expiration date. The field excursion, which scientists are calling “Thwaites invasion,” won’t be easy. The glacier is one of the most hostile places in Antarctica.
Rignot says Operation IceBridge has given his team the data they need to start computing high-resolution models. Their next step is to harness some significant computer power — and pair it with better observations of ocean heat — to try and more precisely forecast sea level rise. “We’ve sort of mapped the heck out of this sector,” Rignot says. “We’ve reached the point now where we have some really nice datasets for the models to run.”
The research from West Antarctica has already prompted the U.S. government to revise its predictions for sea level rise by 2100. A January report by the National Oceanic and Atmospheric Administration reviewed the latest observations from Antarctica and Greenland. It estimated that oceans could rise by 8 feet this century under the worst-case scenario. Their optimistic case: 1 foot. Rignot says the team’s goal isn’t to watch ice sheets collapse. It is to collect evidence so policymakers will listen and take action, even if there’s no way to stop the inevitable.
“We can have an effect on the speed of the retreat of these glaciers,” he says. “If the retreat were to proceed on timescales of 1,000 years instead of a century, it would make a big difference.