A new study raises concerns about a dark and often overlooked consequence of climate change : increased volcanic activity . Melting glaciers due to global warming could trigger more frequent and powerful volcanic eruptions , with climate consequences that could further accelerate the crisis, researchers say.
Hundreds of volcanoes hidden under glaciers in areas such as Antarctica, Russia, New Zealand and North Americamay become active due to the continued rise in global temperatures.
As glaciers retreat due to climate change, the pressure they exert on underground volcanic systems decreases — a condition that, according to geoscientists, can increase the frequency and intensity of volcanic eruptions.
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The findings come from an analysis of six volcanoes in southern Chile, which were studied as part of new research into their behavior during the last glacial period.
"Glaciers tend to suppress the volume of eruptions from volcanoes beneath them. But as glaciers retreat due to climate change, our findings suggest that these volcanoes continue to erupt more frequently and more explosively," said the study's lead author, Pablo Moreno Yaeger, of the University of Wisconsin–Madison.
The science behind the "explosive" cycle
The basic geodynamic principle is simple but powerful: the enormous weight of glaciers compresses the crust Earth's. When they retreat, magma and volcanic gases "lighten" and expand, leading to pressure buildups that fuel powerful eruptions.
This has already been confirmed historically: in Iceland, after the end of the last ice age 10,000 years ago, volcanic activity increased 30 to 50 times.
Global problem
Scientists warn that the global geothermal “trap” includes hundreds of volcanoes covered by or near glaciers, from Antarctica to North America, New Zealand and Russia.
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Specifically, a 2020 study documented 245 possible active volcanoes located under or near ice sheets.
Moreno Yaeger emphasizes that these areas “need more intensive scientific monitoring,” as glacier melting is already underway.
How the past of explosions was deciphered
The risk to continental volcanic systems remains poorly understood. To investigate, geoscientists examined six volcanoes in southern Chile, including the now-dormant Mocho-Choshuenco. They also studied how they responded to the melting of the Patagonian ice sheet thousands of years ago.
They used the radioactive decay of argon, released by volcanic eruptions, as an “isotope clock” and studied crystals that began to form within igneous rocks ejected when the volcanoes erupted. This allowed them to track the volcanic activity of the region and its relationship to the disappearing ice.
They found that 26,000 to 18,000 years ago, during the peak of the last ice age, the ice sheet reduced the volume of eruptions, causing a giant reservoir of magma to build up beneath the surface of the region. When the ice sheet melted, pressure built up inside this reservoir and was eventually released to form the Mocho-Choshuenco volcano.
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From cooling to warming: The double face of volcanic eruptions
In the short term, volcanic eruptions can have an anti-warming effect, as sulfur aerosols reflect solar radiation, temporarily cooling the planet. In many historical cases this has caused cold periods and famines.
But, on a longer time scale, greenhouse gases from these volcanoes contribute to long-term global warming.
"Melting ice causes eruptions, and eruptions amplify warming, which in turn causes more melting," Moreno Yaeger said.
A neglected but critical dimension of the climate crisis
The research reveals a positive feedback mechanism between climate change and geological activity — an area that remains poorly studied, despite the potential impacts on communities, infrastructure, and the global climate.
For the scientific community, this means a need to interconnect the fields of geophysics and climatology. For societies, it means that climate adaptation must also incorporate geodynamic hazards, particularly in areas with volcanic fields beneath glaciers.
Source: www.livescience.com
