As climate change causes glaciers to vanish, scientists are discovering that this loss of ice may be triggering powerful volcanic eruptions.
A new study of six Chilean volcanoes reveals that thick glaciers can suppress eruptions for thousands of years, allowing pressure to silently build in magma chambers deep underground. But once the ice retreats, that pressure is released—sometimes explosively. The findings suggest that Antarctica and other glaciated volcanic regions could see more frequent, intense eruptions in the future, potentially fueling a feedback loop of climate change and volcanic activity.
Glacier Retreat Fuels Future Eruptions
As glaciers melt, they may be quietly setting the stage for more powerful and frequent volcanic eruptions in the future. A new study focused on six volcanoes in the Chilean Andes suggests that climate-driven glacier loss could reawaken hundreds of dormant volcanoes around the world, especially in Antarctica.
The research, presented today (July 8) at the Goldschmidt Conference in Prague, highlights a growing concern among scientists: as glaciers retreat due to climate change, volcanoes that have been sealed beneath thick ice may start to erupt more often and more explosively. While this connection has been studied in Iceland since the 1970s, this is one of the first detailed investigations into how it plays out in continental regions.
Andes Study Reveals Hidden Magma Clues
Scientists from the University of Wisconsin–Madison, working with colleagues from Lehigh University, UCLA, and Dickinson College, studied six volcanoes in southern Chile, including the dormant Mocho-Choshuenco volcano. They used advanced techniques like argon dating and crystal analysis to explore how shifts in the Patagonian Ice Sheet affected volcanic behavior over thousands of years.
By analyzing crystals from past eruptions, the team found that glacial ice plays a major role in shaping volcanic activity. During the height of the last ice age, between 26,000 and 18,000 years ago, thick ice sheets suppressed volcanic eruptions by keeping intense pressure on the Earth’s crust. Beneath this icy lid, a vast reservoir of silica-rich magma slowly built up, trapped deep underground at depths of 10 to 15 kilometers.
When the glaciers began to melt, the pressure dropped. That change allowed gases in the magma to expand, increasing the chances of explosive eruptions. According to the researchers, this same process could now be unfolding in real time as modern glaciers vanish across the planet.
Ice Loss Triggers Explosive Reservoir
As the ice sheet melted rapidly at the end of the last ice age, the sudden loss of weight caused the crust to relax and gasses in the magma to expand. This buildup of pressure triggered explosive volcanic eruptions from the deep reservoir, causing the volcano to form.
Pablo Moreno-Yaeger from the University of Wisconsin-Madison, USA, is presenting the research at the Goldschmidt Conference. He said, “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. 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.
Global Hotspots & Climate Feedback
“Our study suggests this phenomenon isn’t limited to Iceland, where increased volcanicity has been observed, but could also occur in Antarctica. Other continental regions, like parts of North America, New Zealand, and Russia, also now warrant closer scientific attention.”
While the volcanic response to glacial melting is almost instant in geological terms, the process of changes in the magma system is gradual and occurs over centuries, giving some time for monitoring and early warning.
The researchers also note that increased volcanic activity could have global climate impacts. In the short term, eruptions release aerosol (tiny particles in gases) that can temporarily cool the planet. This was seen after the 1991 eruption of Mount Pinatubo in the Philippines, which reduced global temperatures by approximately 0.5 degrees C. But with multiple eruptions, the effects reverse.
Funding, Timeline & Goldschmidt Spotlight
“Over time, the cumulative effect of multiple eruptions can contribute to long-term global warming because of a buildup of greenhouse gases,” said Moreno-Yaeger. “This creates a positive feedback loop, where melting glaciers trigger eruptions, and the eruptions in turn could contribute to further warming and melting.”
The research was funded by the National Science Foundation as part of a grant led by Professor Brad Singer at UW-Madison, and is due to be published in a peer-reviewed journal later this year.
Meeting: Goldschmidt 2025
The Goldschmidt Conference is the world’s foremost geochemistry conference. It is a joint congress of the European Association of Geochemistry and the Geochemical Society (US), and over 4000 delegates attend. It takes place in Prague, Czech Republic, from July 6-11, 2025.
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5 Comments
“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.”
How thick is “very thick?” It appears that their hypothesis is based on evidence from 6 alpine glaciers. Yet, they are making predictions for 1-2-mile thick continental glaciers. That is comparing apples and pineapples. There are no young volcanoes near Chicago, or for that matter, anywhere near the Great Lakes. It seems reasonable to me that IF there are alpine glaciers on the flanks of existing volcanoes, rapid melting will reduce the load and lithostatic pressure on the magma chambers.
The situation is different in West Antarctica. There ARE sub-glacial volcanoes that could be reactivated by massive melting, but the geothermal heat from volcanoes is given no credit for contributing to the melting. It is all blamed on CO2. Interestingly, it appears that what the authors are bringing to the attention of climatologists is that ice loading may be another, previously unappreciated, negative feedback loop that can reduce global surface temperatures for a couple of years for each significant eruption. Another way of looking at this is that glaciation may suppress existing vulcanism, and the associated ash and dust, and thereby contribute to warming. If they could only get past the simplistic way of looking at a complex system and understand that everything is probably interrelated, and it isn’t just anthropogenic CO2 that is changing the world.
Cyclic cold hot periods since earth began
Another example of desperately looking for a influence of man made climate change on naturally occurring phenomena or variations. Studying six Chilean volcanoes that were in the past covered by an ice sheet and then applying the outcome to the whole planet. The studies compares the vast changes during/after ice ages with present day climate change. Disappearing vast ice sheets are not of the same order of disappearing glaciers. The whole article is littered with coulds, mays and suggests. It that science nowadays?
Yes, an ice sheet gives pressure on the underlying crust. It makes sense that this influences the behavior of volcanoes. And yes, today’s climate change makes glaciers melt and it reduces the thickness of ice sheets (a bit). But that’s in the order of some 10s of meters. Nowadays we don’t have melting of complete ice sheets as in Patagonia (1 km thickness) or elsewhere during the ice ages. We don’t have the ice sheet of Antarctica disappearing. At least not in the next 10.000 years. What would be the percentage of pressure reduction of even only 50 meters of ice loss, on a magma chamber building up at 10-15 km depths? I mean, considering on Antarctica the pressure of an average 30 km crust + 3 km ice? Not that significant I think. Projecting the scale of ice age ice loss onto the scale of present day ice loss seems a bit far-fetched.
Something to keep in mind is that rock is typically about 2.5X as dense as ice, meaning that for a given thickness of rock, the lithostatic pressure on the magma chamber is 2.5X as great as an equal thickness of ice.
One might surmise that assorted magma chambers are not necessarily 30kmdeep but that some reside at much shallower depths in the crust. Chilean volcanoes are blessed by emanating from a subduction zone below the Andes. I doubt if Chicago or the Great Lakes benefits from an underlying active subduction zone, and I saw no modern glacial ice-cap in California. New Zealand’s glaciers are not exactly thick and there are no known volcanoes amidst the NZ Southern Alps, which indeed lie along a plate boundary.
A curiosity: there are numerous basaltic volcanic “leaks” gracing the Trans-Antarctic Mountains in the McMurdo Sound region, some of which form “hanging leaks” gracing some valley walls carved out, one presumes, by glacial ice. I don’t know if these have been dated.
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