Well, the number of people that believe that something is true doesn't have any influence on whenever it really is or not. It's a logical fallacy. Like Copernico proposed heliocentrism when everyone believed in geocentrism.
Its for their own sake! The people who deny climate change are backed up by big companies that will be affected if regulations were approved.
Its all about the money i think. Hope we could still reverse the effect before its too late.

Yeah, this can be a cause.