In a Warmer World, Iceland’s Volcanoes May Get Even Livelier
The volcanic eruption in Iceland that has disrupted air traffic in Europe is also a reminder that other volcanoes in the region could wake up if global warming continues unabated, experts say.
Scientists say that if large icecaps on the island melt, they’ll ease the pressure on the rocks beneath the surface. Lifting the weight off the rocks would allow for more magma production, which could set off other eruptions. Says volcanologist Freysteinn Sigmundsson: “Our work suggests that eventually there will be either somewhat larger eruptions or more frequent eruptions in Iceland in coming decades” [Scientific American].
Scientists clarified that while the current Eyjafjallajokull eruption occurred beneath a small glacier in Iceland, the explosion was not caused by global warming. The Eyjafjallajokull glacier is too small and light to have an impact on local geology, they say.
Sigmundsson and his colleague Carolina Pagli published research in 2008 estimating that the melting of about a tenth of Iceland’s biggest icecap, Vatnajokull, over the last century had caused the land to rise about an inch a year and led to the growth of a vast mass of magma, measuring about a third of a cubic mile, underground [The Telegraph]. The researchers explain that heated rocks can’t melt into magma when they’re under high pressure–for example, when they’re squashed underneath the weight of an icecap. But when the ice melts, the water trickles away, and the pressure eases off, the rocks can then melt into magma, creating prime conditions for volcanic eruptions. The researchers note that the end of the Ice Age 10,000 years ago was marked by an increase in volcanic activity in Iceland.
They warn that if ice sheets shrink, we can expect to see more eruptions in other frozen places like Alaska, Patagonia, and Antarctica. Says Pagli: “The effects would be biggest with ice-capped volcanoes…. If you remove a load that is big enough you will also have an effect at depths on magma production” [Scientific American].
Image: Wikimedia/Chris 73