In West Antarctica, scientists predict that ice-sheet collapse could raise global sea levels by 3 meters in the coming centuries. But despite the grim (and what seems inevitable) outlook, researchers are documenting a result of the melting that may temporarily slow the collapse. As the ice melts the weight it exerts on the underlying crust—the bedrock beneath West Antarctica—eases, causing the crust to rise rapidly, Katie Langin reports in Science. Some spots could see the crust rise 8 meters over the coming century, which may protect the ice from the warm seawater melting it from below.
Currently, the West Antarctic sheet lies far below sea level in the form of a giant basin that slopes inland to a depth of more than a kilometer. As warming ocean erodes the glaciers that are snagged on ridges in the sea floor, seawater will pour into the basin, lifting ice off the bedrock. “It may just buy the world a few extra decades,” says Rick Aster, a seismologist and an author of the new study. Geophysicist Natalya Gomez modeled the process, finding that rising bedrock might slow ice retreat by raising the bowl and the ridges that stabilize the glaciers. How effective the process is depends on how fast it takes place, a factor of how hot and gooey the underlying mantle is, Langin explains.
Geophysicist Valentina Barletta led a team that tracked changes in elevation using six GPS sensors fixed to the bedrock in locations around the Amundsen Sea. They noticed soon after how quickly the basin was rising, in some places more than 4 centimeters per year. Still, glaciologist Ted Scambos cautions against premature relief. “It’s not a get out jail free card,” he warns. “It’s more of a refinement on the pace of [ice sheet] collapse.”