December 22, 2017
WASHINGTON — Climate change fueled by human activity could boost the frequency and severity of volcanic eruptions, a recent scientific study has found.
The reason: As the planet warms and glacial ice melts, pressure on magma in the earth’s crust is relieved. Less pressure can result in more eruptions.
A team of researchers led by Graeme T. Swindles, an associate professor of Earth system dynamics at the University of Leeds, published the study last month in the journal Geology. They looked at how small changes in glacial ice impacted volcanic activity in Iceland 4,500 to 5,500 years ago — a period in which the earth cooled and glaciers grew. They created a timeline of Iceland’s volcanic activity by studying the amount of ash that fell into peatlands and lakes across Europe, then compare that with glacial ice cover in Iceland.
What they found was that as ice cover increased, volcanic eruptions declined. Likewise, when those same glaciers retreated, volcanic activity picked up.
Ice “can affect magma flow and the voids and gaps in the Earth where magma flows to the surface as well as how much magma the crust can actually hold,” Swindles told Scientific American magazine in an article published Thursday. “After glaciers are removed the surface pressure decreases, and the magmas more easily propagate to the surface and thus erupt.”
The lag time between these climatic events and the change in eruption frequency was around 600 years, according to the findings.
The researchers note in their study that “human-induced climate change is causing rapid melting of ice in many volcanically active regions.” The findings, they say, suggest that the warming that has occurred since the Little Ice Age — a cold period that spanned from around 1300 and 1850 — could, in time, result in stronger, more periodic eruptions.
“I think we can predict we’re probably going to see a lot more volcanic activity in areas of the world where glaciers and volcanoes interact,” including the Pacific Northwest and southern South America, Swindles said.