Melting glaciers could make volcanic eruptions more explosive, scientists warn

Independent

08-07-2025

Dormant volcanoes across the Earth could become more active and erupt more violently as the climate crisis accelerates glacier retreat, scientists warn in a new study.
The research, presented on Tuesday at the Goldschmidt Conference in Prague, assessed six volcanoes in the Chilean Andes and found evidence that rapidly melting glaciers across the planet could set the stage for more explosive and frequent volcanic eruptions.
A link between retreating glaciers and an increase in volcanic activity has been known since the 1970s from studies conducted in Iceland.
However, the latest research is one of the first to establish this association in continental volcanic systems.
'Our study suggests this phenomenon isn't limited to Iceland, where increased volcanicity has been observed, but could also occur in Antarctica,' said volcanologist Pablo Moreno-Yaeger from the University of Wisconsin-Madison.
'Other continental regions, like parts of North America, New Zealand and Russia, also now warrant closer scientific attention,' Dr Moreno-Yaeger said.
The latest findings could help scientists better predict volcanic activity in glacier-covered regions. In the study, researchers conducted crystal analysis across six volcanoes in southern Chile, including the now dormant Mocho-Choshuenco volcano.
They assessed how the advance and retreat of the Patagonian Ice Sheet influenced past volcanic behaviour in the region.
The analysis of crystals found at these sites helped precisely date previous volcanic eruptions.
It also helped determine how the weight and pressure of glacial ice change the characteristics of magma underground.
Scientists found that during the peak of the last ice age – around 26,000–18,000 years ago – thick ice cover suppressed the volume of eruptions and allowed a large reservoir of silica-rich magma to accumulate 10-15 km below the surface.
Then, as the thick ice sheet melted rapidly at the end of the last ice age, the sudden loss of weight caused the crust to relax, and gases in the magma to expand, according to the yet-to-be peer-reviewed study.
As pressure built up from underneath, it triggered explosive eruptions, causing the volcano to form, researchers found.
'Glaciers tend to suppress the volume of eruptions from the volcanoes beneath them. But as glaciers retreat due to climate change, our findings suggest these volcanoes go on to erupt more frequently and more explosively,' said Dr Moreno-Yaeger.
'The key requirement for increased explosivity is initially having a very thick glacial coverage over a magma chamber, and the trigger point is when these glaciers start to retreat, releasing pressure, which is currently happening in places like Antarctica,' he added.
While glacier melting could be happening currently at unprecedented rates due to global warming, researchers say the process of changes in the magma system due to this happens over centuries, giving some time for monitoring and early warning.