Thwaites Glacier in West Antarctica Melting from Below

Volcanic activity beneath the West Antarctic Ice Sheet is accelerating collapse of the Thwaites Glacier, a new study finds.

Thwaites Glacier is West Antarctica's largest unstable glacier. Recent research has shown that global warming has accelerated calving of the Thwaites glacier. The new study by scientists at the University of Texas at Austin (UTIG) suggests that the glacier isn't just being eroded by warm oceans, but also by volcanic activity.

Scientists knew that geothermal activity beneath the ice sheet was contributing to the collapse of Thwaites. However, current models and data weren't enough to understand how the volcanic activity was affecting the glacier.

UTIG researchers used radar techniques to map how water flows under the ice sheets. Researchers were able to find the ice melt rates as well as identify major sources of thermal activity under the Thwaites Glacier.

The team found that the thermal sources were hotter than previously assumed and they were distributed over a large area.

According to researchers, the crust beneath the West Antarctic ice sheet is rifting, which is the geological term for being pulled apart. This divergence is associated with the movement of magma and volcanic activity beneath the glacier.

Other researchers had assumed that the heat beneath the surface was uniform. However, the new study suggests that the heat is unevenly distributed, which might explain why different parts of the glacier are melting at different rates.

"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." Dusty Schroeder is the lead author of the study.

Researchers have found that the minimum average heat flow beneath the glacier is about 100 milliwatts per square meter. The hotspots register over 200 milliwatts per square meter. To put the numbers in perspective, the average heat flow of the Earth's continents is less than 65 milliwatts per square meter.

Why Study the Thwaites Glacier?

The glacier's interior connects to the West Antarctic ice sheet. The retreat of the "gateway" glacier would expose the ice sheet to a warm ocean. According to researchers, the collapse of the Thwaites glacier could lead to a sea level rise of 1 to 2 meters.

"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 in a news release.

The study is published in the journal Proceedings of the National Academy of Sciences.