Our planet is always on the move, but sometimes it is more restless than usual. As the last ice age came to an end, around 10,000 years ago, there was a surge in volcanic activity as ice caps melted, decreasing pressure on the Earth’s crust.
Since then our planet has reached a steady state, with around 50 volcanoes erupting each year and around 150 earthquakes greater than magnitude six. But geo-hazards expert Bill McGuire is concerned that human-induced climate change may bring a resurgence in activity in the coming centuries. “In areas of major ice loss, such as Alaska, Iceland, the Andes and Himalayas we may see a rise in earthquakes, volcanism and landslides” says McGuire, who describes this scenario in Waking the Giant. “It only takes the pressure of a handshake to trigger a quake or volcanic blast in a primed system.”
Indeed, evidence from the Arctic shows that changes are already afoot. Using aerial photos and satellite imagery Trevor Lantz, from the University of Victoria in Canada, and his colleagues have revealed that landslips have increased up to fourfold over the last fifty years. “Warm summer temperatures increase thaw and higher summer rain can cause slope instability which may initiate slumps,” says Lantz, whose findings are published in Environmental Research Letters.
But volcanologist Dave McGarvie, from The Open University, doubts that current global warming will be enough to stir things up beneath the crust. “The volcanism after the last glaciation was different because it was a relentless and one-way change, with over one kilometre of ice removed over a period of centuries,” he says.
