"When discomfirmatory (contrary) evidence is presented, Festinger found one condition that often determined whether the belief is discarded or maintained with new fervor by belief with a strongloy held belief. That was whether or not the individual believer has social support. It is unlikely that one isolated believer could withstand strong discomfirming evidence. If, however, the believer is a member of a group of convinced persons who can support one another, you might expect the belief to be maintained and the believers to attempt to proselytice or persuade non-members that the belief is correct even in the face of data suggesting otherwise."
The large number of people who have a vested interest in global warming provide support for those who are merely believers in the concept.
The report by the recent conference by climate skeptics is available online.