Thursday, April 22, 2010

Scientists call for research on climate link to geological hazards

Experts say suggestions that climate change could trigger more volcanoes and earthquakes are speculative, but there is enough evidence to take the threat seriously

David Adam, environment correspondent, Monday 19 April 2010

Scientists today called for wide-ranging research into whether more volcanoes, earthquakes, landslides and tsunamis could be triggered by rising global temperatures under global warming.

Significant warming of the atmosphere in the distant past can be linked to changes in geological activity, they say. Suggestions that climate change predicted for coming decades could bring similar changes remain speculative, but the scientists say there is enough evidence to take the threat seriously. Some experts have already linked current levels of global warming to rockfalls and landslides in mountain regions.

Richard Betts, a climate modeller at the Met Office Hadley Centre in Exeter, said: "This is a new area of academic research with potentially interesting implications. It was previously assumed there was no link at all between climate change and these events, but it is possible to speculate that climate change might make some more likely. If we do get large amounts of climate change in the long term then we might see some impacts."

He said there was no evidence that current levels of global warming were influencing events such as last week's earthquake in China that killed hundreds of people and the volcanic eruption in Iceland that grounded flights across Europe.

Experts say global warming could affect geological hazards such as earthquakes because of the way it can move large amounts of mass around on the Earth's surface. Melting glaciers and rising sea levels shift the distribution of huge amounts of water, which release and increase pressures through the ground.

These pressure changes could make ruptures and seismic shifts more likely. Research from Germany suggests that the Earth's crust can sometimes be so close to failure that tiny changes in surface pressure brought on my heavy rain can trigger quakes. Tropical storms, snowfall and shifting tides have all been linked to shifts in seismic activity.

Writing in a special series of scientific papers on the topic published today by the Royal Society, Bill McGuire, head of the Benfield Hazard Research Centre at University College London, says: "In relation to anthropogenic climate change, modelling studies and projection of current trends point towards increased risk in relation to a spectrum of geological and geomorphological hazards in a warmer world, while observations suggest that the ongoing rise in global average temperatures may already be eliciting a hazardous response from the geosphere."

He adds: "In order to improve knowledge and reduce uncertainty, a programme of focused research is advocated ... The IPCC [Intergovernmental Panel on Climate Change] is also strongly exhorted to address more explicitly in future assessments the impact of anthropogenic climate change on the geosphere, together with its manifold potentially hazardous consequences."

The papers follow a special meeting on the subject last year and are published in the journal Philosophical Transactions of the Royal Society A. They include studies of the likely impact of rising temperatures on events such as earthquakes and volcanoes, as well as whether the release of gas from undersea deposits called gas hydrates could trigger landslides and tsunamis.

McGuire says: "No increase in the global incidence of either volcanic activity or seismicity has been identified to date ... It may be the case that modulation of potentially hazardous geological processes due to anthropogenic climate change proves too small a signal to extract from the background noise of normal geophysical activity, at least in the short to medium term."

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