Friday, April 16, 2010

Oh no! Climate change 'may cause eruptions'

Does climate change have to horn in on everything? From the Irish Times: A thaw of Iceland's ice caps in coming decades caused by climate change may trigger more volcanic eruptions by removing a vast weight and freeing magma from deep below ground, scientists said today. They said there was no sign that the current eruption from below the Eyjafjallajokull glacier that has paralysed flights over northern Europe was linked to global warming. The glacier is too small and light to affect local geology.

"Our work suggests that eventually there will be either somewhat larger eruptions or more frequent eruptions in Iceland in coming decades," said Freysteinn Sigmundsson, a vulcanologist at the University of Iceland. "Global warming melts ice and this can influence magmatic systems," he said. The end of the Ice Age 10,000 years ago coincided with a surge in volcanic activity in Iceland, apparently because huge ice caps thinned and the land rose.

"We believe the reduction of ice has not been important in triggering this latest eruption," he said of Eyjafjallajokull. "The eruption is happening under a relatively small ice cap". Carolina Pagli, a geophysicist at the University of Leeds, said there were risks that climate change could also trigger volcanic eruptions or earthquakes in places such as Mount Erebus in Antarctica, the Aleutian islands of Alaska or Patagonia in South America.

"The effects would be biggest with ice-capped volcanoes," she said. "If you remove a load that is big enough you will also have an effect at depths on magma production."…

NASA image by Robert Simmon: Iceland’s Eyjafjallajökull Volcano burst into life for the first time in 190 years on March 20, 2010. A 500-meter- (2,000-foot) long fissure opened in the Fimmvörduháls pass to the west of the ice-covered summit of Eyjafjallajökull. Lava fountains erupted fluid magma, which quickly built several hills of bubble-filled lava rocks (scoria) along the vent. A lava flow spread northeast, spilling into Hrunagil Gully. This natural-color satellite image shows lava fountains, lava flows, a volcanic plume, and steam from vaporized snow.

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