Climate change may trigger more volcanic eruptions

Climate change could spark more volcanic eruptions, earthquakes and landslides, say scientists.

In papers published by the Royal Society today, researchers warned that predicted consequences of rising temperatures such as melting ice, rising sea levels and even increasingly heavy storms and rainfall could affect the Earth's crust.

Even small changes in the environment could trigger activity such as earthquakes and tsunamis and some evidence suggests the consequences of climate change were already having an impact on geological activity in places such as Alaska, say researchers writing in the journal the Philosophical Transactions of the Royal Society A.

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Bill McGuire, of the Aon Benfield UCL Hazard Research Centre at University College London, and the author of a review in the journal of research in the area, said warming temperatures melted ice from ice sheets and glaciers and increased the amount of water in the oceans.

The land "rebounds" back up once the weight of the ice has been removed – by as much as a kilometre ( 0.6 of a mile) in places such as Greenland and Antarctica. In the worst case scenario, all the ice were to melt it could trigger earthquakes.

The increase in seismic activity could, in turn, cause underwater landslides that spark tsunamis. A potential additional risk is from "ice-quakes" generated when the ice sheets break up, causing tsunamis which could threaten places such as New Zealand, Newfoundland and Chile.

The reduction in the ice could also stimulate volcanic eruptions, according to the research.

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The greater weight of the water in the oceans where sea level has risen as ice melts could "bend" the Earth's crust. This produces magma and causes volcanic and seismic activity in coastal or island areas – where the majority of 550 volcanoes whose eruptions have been historically documented are found.

Increased volcanic activity could cause more landslides, and have impacts well beyond the area where the volcano is situated – for example by releasing sulphur clouds into the atmosphere or by affecting air travel.

Prof McGuire said the changes could occur in the coming decades or over centuries, rather than thousands of years, depending on factors such as how quickly sea levels rose.

He warned: "The rise you may need may be much smaller than we expect. Looking ahead at climate change, we may not need massive changes."

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His review said there was mounting evidence of seismic and volcanic activity being triggered by small changes.

Prof McGuire said that in Taiwan the lower air pressure generated by typhoons was enough to "unload" the crust by a small amount and trigger earthquakes.

Other impacts of rising temperatures include glacial lakes bursting rock dams and causing flash flooding in regions such as the Himalayas.

The Philosophical Transactions of the Royal Society A deals with mathematical, physical and engineering sciences.