Just as we get the good news of Arnie signing an historic deal on climate change in California, there are more dire predictions on the issue from the scientists. This time from Professor Peter Cox, of Exeter University in the UK, who told the Royal Geographical Society annual conference that temperatures could rise 8C by 2100 because of a “compost effect” which could see carbon dioxide levels increase 50 per cent faster than previously estimated.

Currently, around one quarter of carbon emissions are absorbed by the soil and one quarter by the oceans. It had previously been assumed that these proportions would remain the same. But Professor Cox said that global warming is damaging the soil’s ability to absorb carbon emissions.

He said this vicious circle would reach crisis point in 2050 when a key threshold would be passed. After this point the land would begin to release carbon into the atmosphere. He predicted that this “compost effect” would lead to carbon dioxide levels rising from the current 380 parts per million to more than 1,000 parts per million by 2100.

At that point we are in real trouble. Sobering thoughts.