Bog unleashes giant methane cloud
The thawing of the world's largest peat bog will release billions of tons of methane, a potent greenhouse gas, and scientists believe little can be done to stop it.The landscape is rapidly changing in a huge expanse of western Siberia, roughly the size of Germany and France combined, as the frozen tundra, enveloped in permafrost for millennia, turns into a series of shallow lakes.
The worrying development, highlighted in New Scientist this week, has sparked a concerned outcry from environmentalists and renewed calls for urgent reduction in carbon emissions.
Since the onset of climate change temperatures in the Siberian sub-Arctic have risen faster than almost anywhere else in the world and the thaw has now started what Sergei Kirpotin, a botanist from Tomsk State University, described as an 'ecological landslide that is proabably irreversible and is undoubtedly connected to climate warming'.
He told the New Scientist that the dramatic melt had been extremely rapid, happening over just three or four years.
Average temperatures in western Siberia have risen by 3 degrees Celsius over the last 40 years, a rise most scientists put down to a combination of man-made climate change, natural cycles and the fact that as snow and ice melt to reveal land and water the darker, uncovered areas absorb more heat.
The precise impact of the melt is not yet known, but the Siberian bogs hold an estimated 70 billion tonnes of methane, a greenhouse gas 20 times more potent than carbon dioxide.
Campaign group Friends of the Earth has seen the melt as evidence that the Earth is reaching its "tipping point" - the point at which a slight rise in temperature triggers major change and expressed fears the methane could significantly accelerate the climate change process.
Tony Juniper, FoE's executive director, said: "This is clearly very worrying.
"We had not expected to see effects of climate change like this quite so soon - but it shows that there is an urgent need for governments to take international action to stabilize our climate or we will face devastating consequences.
"Tony Blair and other international leaders must pay attention to this stark warning ahead of the Montreal climate talks this December.
"They must agree tough action to tackle man-made greenhouse gas emissions. Time is running out."
By Sam Bond