Claude Allegre is one of France's best known climate change deniers. He's a geochemist, which gives him some measure of scientific expertise, although not in a particularly relevant field. He also thinks asbestos is harmless, and doesn't really get gravity, but nevertheless has been able to raise enough of a stink over the past couple of years (the CRU emails--"Hide the decline!" and so on) that finally, this year, the French Academy of Science took a look at the matter.
Their main conclusion was an obvious one:
"Several independent indicators show an increase in global warming from 1975 to 2003. This increase is mainly due to the increase in the concentration of carbon dioxide," the academy said in conclusion to the report.
"The increase in carbon dioxide, and to a lesser degree other greenhouse gases, is unquestionably due to human activity," said the report, adopted unanimously by academy members.
But note that the report was "adopted unanimously" by members of the academy. Claude Allegre is a member of the academy, and he
...signed off on the report.
"He has the right to evolve," the academy's president Jean Salencon said. Pecresse said: "The debate is over."
Of course, Allegre disputes how much evolving he actually did, noting that the word "uncertainty" is used a number of times in the Academy's report. But when you go from saying that the causes of AGW are a mystery to putting your signature on a statement to the exact opposite effect, its quite something.
PS. This fellow suggests it was less a case of evolution than Allegre having his ass handed to him by the academy. Either way is good with me.