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When measured across geological timescales that span eons, it’s fair to say the massive Thwaites Glacier in West Antarctica is in the midst of a collapse. Now new data drawn from the seafloor suggests that it could retreat even faster than previously thought, leading to dramatic impacts on global sea levels.
If the entirety of the Florida-sized ice sheet and some surrounding ice were to slide into the ocean, it could raise sea levels by three to ten feet spelling potential devastation for a number of coastal communities worldwide.
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 a number of places. The worst case scenario were we to lose the Thwaites would redraw coastline maps around the world.
New research in Nature Geoscience shows that Thwaites has retreated surprisingly quickly in the past, suggesting it could do so again in the near future.
“Our results suggest that pulses of very rapid retreat have occurred at Thwaites Glacier in the last two centuries, and possibly as recently as the mid-20th Century,” study lead and marine geophysicist Alastair Graham at the University of South Florida said in a statement.
A 3D-rendered view of the multibeam bathymetry (seafloor shape) colored by depth, collected across a … [+]
By analyzing geologic features on the seafloor created during previous retreats of the glacier, the researchers were able to determine that during a period of just a few months at some point in the last two centuries the glacier retreated at a rate of more than 1.3 miles per year. That’s double the rate 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 over small timescales in the future—even from one year to the next—once the glacier retreats beyond a shallow ridge in its bed,” said marine geophysicist and study co-author Robert Larter from the British Antarctic Survey.
Graham says the findings contradict earlier assumptions that Antarctic ice sheets are relatively slow to respond to changes in climate.
“Just a small kick to Thwaites could lead to a big response,” he said.
Next the team hopes to sample sediments from the seafloor to get more accurate dating for the glacier’s previous movements.
