Siberia starts to melt

The world's largest frozen peat bog has started to melt for the first time since it was formed 11,000 years ago.

Scientists fear the thawing of a vast expanse of western Sibera could dramatically increase the rate of global warming.

Researchers found that an area of permafrost spanning a million square kilometres - the size of France and Germany combined - has started to melt.

Scientists fear it will release billions of tonnes of methane, a greenhouse gas 20 times more potent than carbon dioxide, into the atmosphere.

The discovery was made by Sergei Kirpotin at Tomsk State University in western Siberia and Judith Marquand at Oxford University and is reported in New Scientist.

Dr Kirpotin told the magazine the situation was an "ecological landslide that is probably irreversible and is undoubtedly connected to climatic warming".

He added that the thaw had probably begun in the past three or four years.

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