HOW A CONSENSUS IS REACHED
CONSENSUS? Yes. And No.
The Miriam Webster dictionary defines consensus as "group solidarity in sentiment and belief". By this definition, there certainly is a "consensus" that man-made CO2 is causing "global warming". The people that espouse this are a "group", they have "solidarity", and it is a "sentiment or belief."
BUT, that don't make it true. The definition of "science" is "knowledge as distinguished from ignorance or misunderstanding".
What exists at this time on the issue of "man-made global warming" are two camps. In one are the celebrities, hollywood types, often uneducated at all let alone in scientific rigor, agenda driven politicians and garden variety nutjobs who adhere to a "belief". Also included in this camp are the so-called "environmental modelers" who all seem to have computers and little else. Most of them deal merely with the speculative "consequences" of a given climate scenario, lacking the ability to actually predict any scenario. It is a childs game of "what if?"
On the other side are actual scientists who, based on actual unedited data, develope hypotheses and attempt to test them. Within this group one may actually find rational thought, minus the hysteria, sane analysis of the data that we do have, and a lack of wild fear-mongering to achieve a left wing, big goverment, anti-capitalist, anti-personal property agenda.