Global Climate Change Science News

[Brian Peacock]

Discussion of planetary boundaries between Mark Lynas and Johan Rockström:

[L'Emmerdeur]

Perhaps we needn't worry overmuch about methane clathrates but it looks like there may be a different sort of long term vicious cycle to consider.

'Melting glaciers could trigger more explosive eruptions globally, finds research'

Melting glaciers may be silently setting the stage for more explosive and frequent volcanic eruptions in the future, according to research on six volcanoes in the Chilean Andes.

Presented today [Tuesday 8 July] at the Goldschmidt Conference in Prague, the study suggests that hundreds of dormant subglacial volcanoes worldwide – particularly in Antarctica – could become more active as climate change accelerates glacier retreat.

The link between retreating glaciers and increased volcanic activity has been known in Iceland since the 1970s, but this is one of the first studies to explore the phenomenon in continental volcanic systems. The findings could help scientists better understand and predict volcanic activity in glacier-covered regions.

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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.

“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.

“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.”

[Brian Peacock]