We have been told by Senator Al Gore and others that "the debate is over. Global Warming is definitely man-made. There is no doubt about it. Over two thousand five hundred of the world's top scientists agree about this."
Hm! I wonder.
Quite apart from the fact that science does not work by consensus and "scientific facts" are not and never have been established by majority vote, allow me to drill down a little into what the senator actually means - or to be more exact, the basis for his statement, which I have no doubt he believes as sincerely as any professional politician believes anything.
Over 2500 of the world's top scientists
are listed by the
IPCC as having contributed papers to its deliberations. The IPCC's findings are, however, their own and do not necessarily reflect the conclusions of the contributing scientists. I believe that Senator Gore's assertion should more accurately read something like "over 2500 of the world's top scientists are listed in IPCC's bibliographies as having contributed. IPCC's conclusions are that the debate is over and that global warming is definitely man-made and IPCC claims that all those scientists believe so, too, on the basis that they have contributed and are listed as such."
Just a touche different, to my mind.
I would put a different gloss on it - but this is just my "take", so make up your own minds before you decide whether you want a cynical old ****** like me on the council for another four years - as follows:
IPCC, a political body with a mission to find evidence for human influence behind global warming, does no original research and does not measure anything (see here for IPCC's Terms of Reference), but reserves the right to draw its own conclusions from original research submitted to it by research scientists, regardless of whether its (IPCC's) conclusions are shared by the contributors. IPCC then claims the backing of all the scientists who have done the research for its own conclusions.
At least one contributor is on public record as having asked for his name to be withdrawn from IPCC's list "because they didn't listen to what I said". He further said that he had to threaten legal action before they reluctantly agreed to take him off the list.
So, when you are told that there is a scientific consensus about the causes of the rather pleasant prospect of a repeat of the Mediaeval Warm Period, when harvests were so plentiful that there was labour to spare from tilling the fields to build most of the great early mediaeval cathedrals ...
Updated 12 Apr 07