Energy

Volcanic Heat Found Under Antarctica’s Fastest-Melting Glacier

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A group of scientists at the University of Rhode Island stumbled on something unexpected when analyzing data brought back from a 2014 expedition to western Antarctica.

Scientists found an abundance of the noble gas Helium-3, indicating there is a volcanic heat source beneath the Pine Island glacier — the fastest-melting glacier in the South Pole. The findings were published in a study in the journal Nature Communications.

“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,” chemical oceanographer Brice Loose, the study’s lead author, said in a statement.

“The volcanic heat sources were found beneath the fastest moving and the fastest melting glacier in Antarctica, the Pine Island Glacier,” Loose said. “It is losing mass the fastest.”

Previous research has identified a network of volcanic rifts beneath Western Antarctica that could be contributing to the ice sheet’s instability. A 2014 University of Texas study concluded that “large areas at the base of Thwaites Glacier are actively melting in response to geothermal flux consistent with rift-associated magma migration and volcanism.”

The Thwaites Glacier is another retreating Antarctic glacier. The heat source beneath Pine Island is 25 times greater than an individual volcano, scientists said.

Loose’s study found that “helium isotope and noble gas measurements provide geochemical evidence of sub-glacial meltwater production that is subsequently transported to the cavity of the Pine Island Ice Shelf.”

Loose and his colleagues cautioned against attributing most of Pine Island’s retreat to volcanic activity. Scientists have warned that global warming will increasingly destabilize Antarctic ice sheets and raise sea levels.

“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,” Loose said.

However, research by the British Antarctic Survey (BAS) found the Pine Island glacier began melting in the 1940s, during a strong El Nino warming event. Pine Island’s melt actually continued through subsequent decades, despite a slight cooling trend through the 1970s.

A separate BAS study from 2014 found the Pine Island glacier thinned at rates similar to 2018 about 8,000 years ago — thousands of years before massive amounts of carbon dioxide emissions were released into the atmosphere.

Still many scientists and activists have sounded the alarm on Antarctic ice melt. A recent assessment of Antarctic data found that ice melt had dramatically increased in recent years, but critics said that work did not take into account modeling errors of the movement of the Earth beneath the ice sheets.

NASA glaciologist Jay Zwally said correcting the model error shows the increased ice melt in western Antarctica is offset by the expansion of the eastern ice sheet.

“Basically, we agree about West Antarctica,” Zwally said. “East Antarctica is still gaining mass. That’s where we disagree.”

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