It is often claimed that the science of man-made global warming or climate change is settled and there is a consensus to which 97% of (or 4,000) climate scientists subscribe. Yet there is no evidence for this claimed consensus
John McLean analysed IPCC AR4 (the fourth IPCC report published in 2007) papers to determine how many scientists and authors explicitly supported the AGW theory. He found only 60 authors and reviewers could be regarded as explicitly supporting the claims about a significant human effect on climate.
Furthermore, 166 climate scientists issued a challenge to Ban Ki Moon on the eve of the Copenhagen Climate Summit in 2009 to provide proof of human induced global warming, saying
that we are in a period of negative discovery, ie. the more we learn, the less convincing is the argument for anthropogenic (or man-made) global warming.
700 scientists have made submissions to the US Senate expressing dissent from the consensus. If you read their submissions, you will learn that speaking out against man-made global warming risks career and professional standing.
Many scientific organisations have endorsed the so called "consensus" but without reference to their members. Hal Lewis resigned publicly from the Americam Physical Society over its refusal to debate its endorsement statement with the membership many of whom were sceptical of the proposition.
A recent "survey" by John Cook and published on the misnamed skepticalscience blog claimed 97% of climate scientists endorsed the AGW theory (human induced climate change). The study was exposed as totally flawed and demonstrated no such conclusion.
If you follow climate science (rather than the media), you will know there is active debate among scientists on both sides (eg. see IPCC author Judith Curry's blog Climate Etc.) about the levels of uncertainty but this is seldom reported in the media. There is an institutional bias on this issue. The IPCC is a political body, its mission statement refers to "human induced climate change" no AGW, no IPCC - it and the climate science funding (plus a whole industry and funding for NGOs etc.) depends on the consensus holding - if it fails too many people have too much to lose.See groupthink.
Irrespective of consensus, scientific facts are not determined by democratic vote - if that were the case we'd still believe the earth is at the centre of the universe and Galileo would be forgotten.