Volcanoes beneath Antarctic ice sheet melting glaciers

Not only climate change, subglacial volcanoes below the West Antarctic ice sheet are also contributing to the melting of Thwaites Glacier - a major river of ice that flows into Antarctica's Pine Island Bay, a study suggests.

"Areas of the glacier that sit near geologic features thought to be volcanic are melting faster than regions farther away from hotspots," said Dustin Schroeder, a geophysicist at the University of Texas at Austin.

The researchers built on a previous study that mapped out the system of channels that flow beneath the Thwaites Glacier, a fast-flowing glacier that scientists say is vulnerable to global warming.

Using data from airborne radar, the researchers were able to figure out where these subglacial streams were too full to be explained by flow from upstream.

"The swollen streams revealed spots of unusually high melt," Schroeder said.

The minimum average heat flow beneath Thwaites Glacier is 114 milliwatts per square metre (or about 10 square feet) with some areas giving off 200 milliwatts per square metre or more, the study showed.

"In comparison, the average heat flow of the rest of the continents is 65 milliwatts per square metre," Schroeder said.

"The extra melt caused by subglacial volcanoes could lubricate the ice sheet from beneath, hastening its flow toward the sea," Schroeder said.

To understand how much the volcanic melt contributes to this flow - and what that means for the future of the West Antarctic ice sheet - glaciologists and climate scientists will have to include the new, finer-grained findings in their models, Live Science reported.

The findings appeared in the journal Proceedings of the National Academy of Sciences.