Scientists of the Intergovernmental Panel on Climate Change (IPCC) are quite certain: by using fossil fuels man is currently destroying the climate and our future. We have one last chance, we are told: quickly renounce modern industrial society – painfully but for a good cause.

For many years, I was an active supporter of the IPCC and its CO2 theory. Recent experience with the UN’s climate panel, however, forced me to reassess my position. In February 2010, I was invited as a reviewer for the IPCC report on renewable energy. I realised that the drafting of the report was done in anything but a scientific manner. The report was littered with errors and a member of Greenpeace edited the final version. These developments shocked me. I thought, if such things can happen in this report, then they might happen in other IPCC reports too.

Good practice requires double-checking the facts. After all, geoscientists have checked the pre-industrial climate, over the past 10,000 years: this isolates natural climate drivers. According to the IPCC, natural factors hardly play any role in today’s climate so we would expect a rather flat and boring climate history.

Far from it: real, hard data from ice cores, dripstones, tree rings and ocean or lake sediment cores reveal significant temperature changes of more than 1°C, with warm and cold phases alternating in a 1,000-year cycle. These include the Minoan Warm Period 3,000 years ago and the Roman Warm Period 2,000 years ago. During the Medieval Warm Phase around 1,000 years ago, Greenland was colonised and grapes for wine grew in England. The Little Ice Age lasted from the 15th to the 19th century. All these fluctuations occurred before man-made CO2.