Everyone knows that volcanoes are exceptionally hot things – that’s why no one expects to find a glacier near, say, Hawaii. However, nowhere on Earth is 100% insulated from geothermal activity: Researchers from the University of Texas at Austin have determined that subglacial volcanic activity, along with climate change, is contributing to the melting of the West Antarctic ice sheet.

The findings significantly change the understanding of conditions beneath the West Antarctic Ice Sheet where accurate information has previously been unobtainable.

“It’s the most complex thermal environment you might imagine,” said co-author Don Blankenship, a senior research scientist at UTIG and Schroeder’s Ph.D. adviser. “And then you plop the most critical dynamically unstable ice sheet on planet Earth in the middle of this thing, and then you try to model it. It’s virtually impossible.”

For the Thwaites Glacier in particular, collapse has gone from “probable” to “inevitable.” Scientists are now more interested in how fast the glacier is melting, and what impact it will have on sea levels when it eventually collapses. Though scientists were aware of subglacial geothermal activity to some degree, lead author Dusty Schroeder and his colleagues used radar techniques to show that the community had previously underestimated the degree of influence geothermal activity was having.

Rather than low, even heat distribution across the bottom, the researchers liken it more to a multi-burner stove, with “hotspots” distributed below the glacier. Not only is it contributing to the melting of Thwaites Glacier, but it also explains why the ice sheet seems to be sliding at such an accelerated rate. The faster it slides into the ocean, the less stable it becomes.

“The combination of variable subglacial geothermal heat flow and the interacting subglacial water system could threaten the stability of Thwaites Glacier in ways that we never before imagined,” Schroeder said.

The collapse of the Thwaites Glacier would cause an increase of global sea level of between 1 and 2 meters, with the potential for more than twice that from the entire West Antarctic Ice Sheet.