Warming hits 'tipping point'
Siberia feels the heat It's a frozen peat bog the size of France and Germany combined, contains billions of tonnes of greenhouse gas and, for the first time since the ice age, it is melting
Ian Sample, science correspondent
Thursday August 11, 2005
A vast expanse of western Siberia is undergoing an unprecedented thaw that could dramatically increase the rate of global warming, climate scientists warn today.
Researchers who have recently returned from the region found that an area of permafrost spanning a million square kilometres - the size of France and Germany combined - has started to melt for the first time since it formed 11,000 years ago at the end of the last ice age.
The area, which covers the entire sub-Arctic region of western Siberia, is the world's largest frozen peat bog and scientists fear that as it thaws, it will release billions of tonnes of methane, a greenhouse gas 20 times more potent than carbon dioxide, into the atmosphere.
It is a scenario climate scientists have feared since first identifying "tipping points" - delicate thresholds where a slight rise in the Earth's temperature can cause a dramatic change in the environment that itself triggers a far greater increase in global temperatures....