Climate change could trigger more volcanic eruptions

Posted by Kate Taylor

As if hurricanes and heat waves weren't enough, a new study indicates that climate change can cause volcanic eruptions too.

The evidence comes from a ten-year research project into the volcanoes of Central America.

"Among other pieces of evidence, we have observations of ash layers in the seabed and have reconstructed the history of volcanic eruptions for the past 460,000 years," says GEOMAR volcanologist Dr Steffen Kutterolf. "There were periods when we found significantly more large eruptions than in others."

And after comparing these patterns with the climate history, there was a clear match, with periods of high volcanic activity following fast global temperature increases and rapid melting of ice. The team followed up by studying other cores from the entire Pacific region, which showed precisely the same pattern.

"In times of global warming, the glaciers are melting on the continents relatively quickly. At the same time the sea level rises," says GEOMAR geophysicist Dr Marion Jegen.

"The weight on the continents decreases, while the weight on the oceanic tectonic plates increases. Thus, the stress changes within in the Earth to open more routes for ascending magma."
The rate of global cooling at the end of the warm phases is much slower, so there are less dramatic stress changes during these times.

"If you follow the natural climate cycles, we are currently at the end of a really warm phase. Therefore, things are volcanically quieter now," says Kutterolf. "The impact from human-made warming is still unclear based on our current understanding."