IPCC's Fritz Vahrenholt: "I realised that the drafting of the report was done in anything but a scientific manner. The [IPCC renewable energy] report was littered with errors and a member of Greenpeace edited the final version. These developments shocked me"

Global warming: second thoughts of an environmentalist - Telegraph

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.

...The choice is no longer between global warming catastrophe and economic growth but between economic catastrophe and climate sense.