The alarmists ala' Al Gore, are as big a part of the problem as those in complete denial about the effects mankind has on our environment. By running around screaming "We're all gonna die if we don't do something NOW!!!!", they gave ammunition to the deniers.
The issue is so muddied with rhetoric and politics that the ordinary American with an 11th Grade knowledge of Science doesn't know who to believe.
The effect of mankind on our environment:
and thus cows, pigs, buffalo, beefalo, horsemeat if you want, and all those other goodies that only an advanced technological and industrialized civilization can provide to support eight billion people.
Without the human's ability to modify his environment for his pleasure, the human race would consist of a few thousand filthy savages hiding from scavengers and not having enough sense to realize they're only living some 30 years.
But to pretend human kind is both able to heat the entire planet, and to pretend that a warmer planet would be worse, when historical evidence proves otherwise, is the hieght of hubristic ignorance.