Climate change is causing 11 billion tons of glacial ice to melt in Iceland every year. The glacial melt, which is happening at a faster rate than earlier believed, results in an annual uplift of 35 mm (1.4 in), as a new study published in Geophysical Research Letters concluded. This may lead to more frequent volcanic eruptions.
“As the glaciers melt, the pressure on the underlying rocks decreases,” Kathleen Compton of the University of Arizona, a geoscientist and one of the paper’s co-authors, explained to TIME. “Rocks at very high temperatures may stay in their solid phase if the pressure is high enough. As you reduce the pressure, you effectively lower the melting temperature.”
“High heat content at lower pressure creates an environment prone to melting these rising mantle rocks, which provides magma to the volcanic systems,” added Arizona geoscientist Richard Bennett, another co-author.
During the last deglaciation period 12,000 years ago—one that took much longer to unfold than the current warming phase—geologic records suggest that volcanic activity across the island increased as much as 30-fold, TIME writes.
The glacial melt and consequential uplift is happening much faster than earlier believed. At the current pace, the researchers predict, the uplift rate in parts of Iceland will rise to 40 mm (15.7 in) per year by the middle of the next decade.
The findings are based on data from 62 GPS sensors that have been arrayed around the country from 1995 to 2009, analyzed by scientists from the University of Arizona and the University of Iceland.
Previous studies have also concluded that the melting of glacial ice in Iceland is causing uplift and may lead to more frequent eruptions.