Well Mr Allegre must have read your post about global warming on Mars (still a ridiculus idea)

You do realize he's a former scientist turned politician (and well past retirement age). And we all know how much we can trust politicians....

For more fun facts
http://www.realclimate.org/index.php/archives/2006/10/con-allegre-ma-non-troppo/

Allègre mentions two scientific examples to demonstrate that there is something fundamentally wrong in the IPCC statements on the reality of climate change. First, he commented on the disappearing glaciers of the Kilimanjaro, sometimes treated as the “Panda” of anthropogenic climate change. Citing a "Nature" study (which was in fact published in Science) by Pierre Sepulchre and colleagues from my laboratory, he claimed that this modelling study demonstrated that Kilimanjaro’s glaciers are controlled by tectonic activity. In fact, the article describes the impact of tectonics of the East African Highlands on Indian ocean moisture transport ---- on a time scale of millions of years! This confuses glacier variability over the last ~100 years with rainfall trends extending back to the time of the early hominids

Allègre's misunderstanding was immediately followed by another one. Citing a recent study on relatively stable Antarctic snowfall over the last 30 years (Monaghan et al, 2006, discussed here) , he highlighted what he thought was a clear contradiction to future climate simulations of global circulation models (melting of the Antarctic ice sheet). However, that's not what they predict. All models predict a comparably stable Antarctic ice sheet for the 21th century in which comparably moderate temperature changes in Antarctica are compensated by slight increase in snowfall. The Monaghan et al study does not contradict these model scenarios.

Nice post, but incomplete. There are a few things you did not say.

Firstly, Allegre was one of the worst ministers of education we've had in the last decades. He managed to have students from high school up in the streets demanding his resignation for a full month, Which had not happened since may of 1968. I should know, I was there in the streets chanting with the others (not in 1968, in 1999)

Secondly, he's not "prominent" anymore. After his bief tenure as minister, he completely faded from th public eye.

Thirdly and finally, he's a geologist, who turned to politics because, frankly, he was no good at science. Since he became a politican, he's stopped doing science. So I wouldn't trust him on anything scientific-related, nor take his opinion as representative of anything but a bad-scientist-turned-bad-politician's opinion.

As for the scientific arguments he made, frankly, neologizer picked at them better than I could, and for a siple reason : this did not make the news in France (so much for the notoriety of Allegre) so I didn't review them.