A study has found that a temperature rise of 2˚C above pre-industrial levels would thaw about 40% of permafrost which covers almost a quarter of the land of the Northern Hemisphere, releasing billions of tonnes of carbon into the atmosphere.

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A study has found that a temperature rise of 2˚C above pre-industrial levels would thaw about 40% of permafrost which covers almost a quarter of the land of the Northern Hemisphere, releasing billions of tonnes of carbon into the atmosphere.