Of course, the real problems with the 97% of "all scientists" claim are such that if it were true, it would still be irrelevant to the truth of the matter. First, most scientists are not experts on climatology, so their views are as relevant as those collected in a random survey of the populace at large. Second, scientific truth has never been established by consensus (cf. the history of our understanding of the causation of peptic ulcers and the fate of the book entitled 100 Authors Against Einstein, to the publication of which Einstein remarked "If I had been wrong, one would have sufficed.").
It may well be that 97% of climatologists will assent to some version of anthropogenic causation for recent shifts in climate, but that is not actually evidence of the truth of the matter, any more than the fact that about 10 years ago about 97% of theoretical physicists regarded string theory as the solution to all of the open problems in fundamental physics "proved" string theory was right. Almost no theoretical physicists are working in string theory now, as it simply didn't work as advertised.