Saturday, September 19, 2009

Is global warming linked to volcanic eruptions?

A team of geologists is trying to gather data in an attempt to understand how global warming will increase the explosiveness of volcanic eruptions.

As increasing atmospheric carbon dioxide levels warm the planet, the problems associated with melting ice won’t just raise sea-levels; they will also uncap volcanoes.

But just when and how these unstable magmatic beasts will blow in a warmer world is hard to predict.

“The fact is we are causing future contemporary climate change. Geological hazards are another portfolio of things we haven’t thought of,” Bill McGuire from the Aon Benfield UCL Hazard Research Centre at University College London told Nature News.

He organized a meeting of volcanologists and oceanographers at the university on September 15-17 to draw attention to the problem.

A priority is to develop global models of how changes in the climate bring about changes in geological activity, and how those processes feed back into the system.

At present, such models just don’t exist, according to David Pyle, a volcano expert from the University of Oxford, UK, who spoke at the meeting.

“As thick ice is getting thinner, there may be an increase in the explosivity of eruptions,” he said.

The problem is complex, exacerbated by the difficulty of separating forcing by the climate from the effects of a volcanic eruption - aerosols emitted by an eruption will have consequences for atmospheric chemistry, which in turn affect the climate.

“The complex consequences of volcanic activity for the atmospheric biosphere remain poorly understood,” Pyle said.

But there is definitely some evidence that less ice means more dramatic eruptions.

“As thick ice is getting thinner, there may be an increase in the explosivity of eruptions,” said Hugh Tuffen from Lancaster University, UK.

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