I am not arguing that all actions designed to limit or reduce ‘greenhouse gas’ emissions are necessarily pointless or misguided. Given past history and the present situation, I am in favour of a carbon tax, provided that it can be made to work and is kept revenue-neutral. Again, I do not take the position that prevailing scientific opinion is wrong: there is a clear and well recognized difference between questioning and denial, between being an agnostic and being an atheist All the same, I have come to the view that today’s received opinion on climate change issues is not well founded. I believe that it incorporates three mutually reinforcing and unwarranted presumptions. These are 1) That the official policy consensus, as widely interpreted today by governments and international agencies, mirrors prevailing scientific opinion and goes no further than it would warrant 2) That prevailing scientific opinion must now be viewed as no longer open to serious question 3) That the process of review and inquiry from which prevailing scientific opinion has emerged, and in particular the IPCC process as its leading element, are professionally above reproach ll these beliefs are unfounded. They show a lack of awareness respectively of the present extent of overstatement, overconfidence, and ingrained bias.