A draft copy of the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, obtained by The Observer, shows the frequency of devastating storms - like the ones that battered Britain last week - will increase dramatically. Sea levels will rise over the century by around half a meter; snow will disappear from all but the highest mountains; deserts will spread; oceans become acidic, leading to the destruction of coral reefs and atolls; and deadly heatwaves will become more prevalent.

"The really chilling thing about the IPCC report is that it is the work of several thousand climate experts who have widely differing views about how greenhouse gases will have their effect. Some think they will have a major impact, others a lesser role. Each paragraph of this report was therefore argued over and scrutinized intensely. Only points that were considered indisputable survived this process. This is a very conservative document - that's what makes it so scary," said one senior U.K. climate expert.