Warm water is sneaking underneath the Thwaites Glacier — and rapidly melting it
In Antarctica, the warm ocean is stealthily attacking a major glacier through a previously unknown route — undermining its foundation on a daily basis.
As each rising tide lifts the coastal terminus of the southern continent’s Thwaites Glacier a tiny bit off the seafloor, warm salty water squeezes in underneath, satellite measurements reveal. This inrush of seawater forces its way many kilometers inland as it melts the ice from beneath. The melt water and seawater are then flushed back out as the tide falls, researchers report May 20 in the Proceedings of the National Academy of Sciences.
”That is going to greatly accelerate the retreat” of the ice in some places, says Theodore Scambos, a glaciologist at the University of Colorado Boulder who was not part of the study.
The West Antarctic Ice Sheet, where Thwaites Glacier resides, is a fortress besieged by enemies. This dome of ice the size of Alaska sits in a bowl-shaped ocean basin. The edges of the ice sheet, where it rises off the seafloor, are constantly assaulted by warm, dense, salty ocean currents that pour across the seafloor like invading armies.
The thermal assault is especially ferocious along the section of coastline where Thwaites, a rapidly moving corridor of ice 120 kilometers across, empties into the ocean. Thwaites is currently hemorrhaging 75 billion tons of ice per year — accounting for roughly half the ice lost from all of Antarctica. [Continue reading…]