I remember reading an interview with Julian Simon where he tried to fathom why the pessimists (notably Paul Ehrlich) were drawing crowds while he was addressing small roomfuls of listeners. Bob Nelson suggests that it is the attraction of "Calvinism without God."
AEI's Joel Schwartz ("Air Pollution and Health: How Do Popular Portrayals Reflect the Scientific Evidence?") addresses the latest batch of environmental bad news bearers.
There is always piling on by the high-minded. I attended a grade school "winter sing" in Los Angeles a couple of years ago where the poor kids were made to sing about recycling. Parents and teachers around the room appeared to be quite comfortable with the substitution of modern concerns for the seasonal cheer that they may have grown up with.