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When measured on geological time scales spanning eons, it is fair to say that the massive Thwaites Glacier in West Antarctica is in the midst of a collapse. Now, new data from the seafloor suggests it could recede even faster than previously thought, causing dramatic impacts on global sea levels.
If all of the Florida-sized ice sheet and some of the surrounding ice were to slide into the ocean, it could raise sea levels between three and ten feet, potentially causing devastation to several coastal communities all over the world
For context, we’ve seen less than a foot of sea level rise over the past three decades, and that’s been enough to increase flooding in several places. Worst case if we lost the Thwaites it would redraw the coastline maps around the world.
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New research in Nature Geoscience shows that Thwaites has retreated surprisingly quickly in the past, suggesting it may do so again in the near future.
“Our results suggest pulses of very rapid retreat have occurred on Thwaites Glacier in the last two centuries, and possibly as recently as the mid-20th century,” said study leader and marine geophysicist Alastair Graham of the University of South Florida in a statement. .
A 3D view of multibeam bathymetry (shape of the seafloor) colored by depth, collected through a … [+] seafloor ridge, just in front of the Thwaites Ice Shelf.
Alastair Graham/University of South Florida
By analyzing geological features on the seafloor created during previous retreats of the glacier, the researchers were able to determine that over a period of just a few months sometime in the last two centuries, the glacier retreated at a rate of over 1.3 miles per course. That’s twice the rate at which satellites documented its retreat between 2011 and 2019.
“Thwaites is really holding on today by its fingernails, and we should expect to see big changes on small time scales in the future, even from year to year, once the glacier retreats beyond a shallow ridge in its bed,” said the marine geophysicist. and study co-author Robert Larter of the British Antarctic Survey.
Graham says the findings contradict previous assumptions that Antarctic ice sheets are relatively slow to respond to climate changes.
“Just a small kick to Thwaites could cause a big response,” he said.
Next, the team hopes to sample seafloor sediments to get a more precise dating of the glacier’s past movements.