It’s concerning enough that glaciers in Greenland and Antarctica—including the infamous Doomsday Glacier —are melting at a fast rate causing the ocean’s great “conveyor belt” to pump the brakes. But according to new research, all that melted ice could lead to an unexpected phenomenon here on land. Without sufficient ice cover to suppress the world’s magma stores, volcanoes could begin to erupt more freely.

In the 1970s, researchers linked a surge of volcanic activity in Iceland to the retreating glacier known as Sandfellsjökull, which is part of the Mýrdalsjökull ice cap. Because Mýrdalsjökull rests above the country’s Katla volcano, they theorized that as its glaciers melt, pressure on the volcano’s magma chambers decreases, making it easier for eruptions to occur. Until just recently, though, no one had studied the connection between melting glaciers and continental volcanoes.  

In a presentation at the Goldschmidt Conference on geochemistry this Tuesday, a team of researchers from California, Pennsylvania, and Wisconsin noted that the dynamic between Sandfellsjökull and Katla likely occurs between other glaciers and volcanoes. They studied six volcanoes scattered throughout southern Chile, curious as to whether the advance and retreat of the Patagonian Ice Sheet might have influenced their behavior. Using argon dating, the team mapped the volcanoes’ previous eruptions. Then they used crystals wedged within erupted rocks to trace how weight and pressure changes in above-ground ice altered the magma deep within the volcanoes’ chambers. 

Their work revealed a startling timeline. A thick layer of ice that existed 18,000 and 26,000 years ago—during the peak of the Pleistocene Epoch, otherwise known as the last ice age—had suppressed any potential eruptions, leading to the accumulation of silica-rich magma between 10 and 15 kilometers (6 and 9 miles) beneath the surface. But as the ice age came to a close, the ice cover retreated. Earth’s crust relaxed, and the magma reservoir expanded, eventually leading to a series of eruptions that formed the volcanoes themselves. 

“Our study suggests this phenomenon isn’t limited to Iceland, where increased volcanicity has been observed, but could also occur in Antarctica,” said University of Wisconsin-Madison graduate student Pablo Moreno-Yaeger, who was involved in the research. “Other continental regions, like parts of North America, New Zealand and Russia, also now warrant closer scientific attention.”

Moreno-Yaeger and his colleagues believe that as glaciers around the world continue to melt at an increased rate, volcanoes could follow Katla’s lead. That “creates a positive feedback loop,” he said, “where melting glaciers trigger eruptions, and the eruptions in turn could contribute to further warming and melting.”