First, to mean anything, one would need assurances that negative articles would have an equal chance of publication (they do not)...
Second, one would need assurances that there would be no reprisals taken on those scientists who disagree (reprisals would be nearly certain in some circles, one suspects)... and
Third, I suspect multiple counting of authors (ol suspicious moi)....
Fourth, for this count comparison to have validity, there would need to be no profit or prestige incentive for one's research to support such a politically correct notion (such incentives are more than obvious).
It would be much more, ahem, "scientific" to invite critics to address an hypotheses (which global climate change might not even qualify to be), than to count the "ins" and "me too's".
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You're right to be suspicious. I'd also be willing to bet that many of those who are being counted aren't scientists at all, or are "scientists" in non-climate related disciplines. A previous poll (1990s) of 3,000 "scientists" who said AGW was real, turned out to be a handful of actual climatologists and meteorologists, and a whole slew of social workers, grad students, and so on. Wish I could find a link to the article which exposed it.
Scouts Out! Cavalry Ho!