Scientists from the University of East Anglia have helped discover an active volcanic heat source under Antarctica’s fastest melting glacier.

They are part of an international team to find that a volcanic heat source under the Pine Island Glacier plays an important role in its movement and melting.

The findings, published in Nature Communications, are critical to understanding the stability of the West Antarctic Ice Sheet of which the Pine Island Glacier is a part.

But the research team say that climate change is still causing the bulk of glacial melt.

The team conducted a major expedition to Antarctica in 2014 and worked aboard an icebreaker, the RRS James Clark Ross, from January to March - Antarctica’s summer.

Prof Karen Heywood, from UEA’s School of Environmental Sciences and chief scientist for the expedition, said: “We measured a gas called helium in the water coming out of the cavity beneath a floating ice shelf.  This gas comes from the earth’s mantle, where there are active volcanoes under the Antarctic ice sheet.

“The discovery of volcanoes beneath the Antarctic ice sheet means that there is an additional source of heat to melt the ice, lubricate its passage towards the sea, and adding to the melting from warm ocean waters.  

“It will be important to include this in our efforts to estimate whether Antarctic ice sheet might become unstable and further increase sea level rise."

Lead researcher Prof Brice Loose from the University of Rhode Island (US) said: “We weren’t looking for volcanism. When we first started seeing high concentrations of helium-3, we thought we had a cluster of bad or suspicious data.”

The West Antarctic Ice Sheet lies atop a major volcanic rift system, but there had been no evidence of current magmatic activity. The last such activity was 2,200 years ago.

And while volcanic heat can be traced to dormant volcanoes, what the scientists found at Pine Island was new.

“You can’t directly measure normal indicators of volcanism — heat and smoke —  because the volcanic rift is below many kilometers of ice,” said Prof Loose.

“When you find helium-3, it’s like a fingerprint for volcanism. We found that it is relatively abundant in the seawater at the Pine Island shelf.”

However, the team have cautioned that the findings do not imply that volcanism is the major source of mass loss from Pine Island. 

On the contrary, “there are several decades of research documenting the heat from ocean currents is destabilizing Pine Island Glacier, which in turn appears to be related to a change in the climatological winds around Antarctica,” said Prof Loose.

Instead, this evidence of volcanism is a new factor to consider when monitoring the stability of the ice sheet.

Heat energy released by the volcanoes and hydrothermal vents suggests that the heat source beneath Pine Island is about 25 times greater than the bulk of heat flux from an individual dormant volcano.

Does that mean that global climate change is not a factor in the stability of the Pine Island Glacier?

No, said Prof Loose. “Climate change is causing the bulk of glacial melt that we observe, and this newly discovered source of heat is having an as-yet undetermined effect, because we do not know how this heat is distributed beneath the ice sheet.”

Other studies have shown that melting caused by climate change is reducing the size and weight of the glacier, which reduces the pressure on the mantle, allowing greater heat from the volcanic source to escape and then warm the ocean water.

“Predicting the rate of sea level rise is going to be a key role for science over the next 100 years, and we are doing that. We are monitoring and modelling these glaciers,” added Prof Loose.

The research was carried out in collaboration with the National Oceanography Centre at the University of Southampton, Arizona State University’s School of Earth and Space Exploration, the Lamont-Doherty Earth Observatory at Columbia University William, the Woods Hole Oceanographic Institution in Massachusetts; and the British Antarctic Survey.

‘Evidence of an active volcanic heat source beneath the Pine Island Glacier’ is published in the journal Nature Communications.