getty When measured on geologic time scales spanning centuries, it is fair to say that the massive Thwaites Glacier in West Antarctica is in the midst of collapse. Now new data pulled from the sea floor suggests it could recede even faster than previously thought, leading to dramatic effects on global sea levels. If the entire Florida-sized ice sheet and some surrounding ice were to slide into the ocean, it could raise sea levels by three to ten feet, causing potential disaster for some coastal communities around the world. For context, we’ve seen less than a foot of sea level rise in the past three decades, and that’s been enough to increase flooding in some places. Worst case scenario if we lost the Thwaites we would redraw coastline maps around the world. MORE FROM FORBES ‘Doomsday Glacier’ The size of Florida could begin to collapse this decade, recreating coastlines worldwide By Eric Mack 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 on Thwaites Glacier over the past two centuries, and possibly into the mid-20th century,” study leader and marine geophysicist Alastair Graham of the University of South Florida said in a statement. . A depth-colored 3D rendering of multibeam bathymetry (seafloor mapping), collected in a … [+] Seabed ridge, just in front of the Thwaites Ice Shelf. Alastair Graham/University of South Florida By analyzing geological features on the sea floor 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 greater than 1.3 miles per year. That’s twice the rate at which satellites documented its retreat between 2011 and 2019. “Thwaites is really holding on today by its claws, and we should expect to see big changes at short intervals in the future – even from one year to the next – when the glacier retreats past a shallow ridge in its bed.” , said 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 change. “Just a small kick to Thwaites could lead to a big response,” he said. Next, the team hopes to sample sediments from the sea floor to get more precise dating for past glacier movements.
