The public tends to trust "Science" to tell us the truth. Put a lab coat and a stethoscope on someone and we tend to trust them more than we normally would trust a stranger. Society respects the hard work that was required to earn that lab coat, whether a true scientist is wearing it or an actor who "plays one on T.V." Looking the part and fulfilling the role are two different things.
Some "scientists" (better called pseudo-scientists) stick to their guns and defend bad theory long after reason and common sense dictate other actions are more rational for two reasons - peer pressure and funding. It's tough to go against the flow of conventional wisdom and tell the world that global warming is a farce.
Bjorn Lomborg was an established and respected liberal scientist who believed completely in global warming and for that reason set out to disprove the theories of American economist Julian Simon. Simon claimed the world's environment was improving and not getting worse.