I don't believe in global warming. Well, I do believe it's warming, but it has been since the last ice age. I remember the democrats ranting during the Carter administration about global cooling and the coming ice age. They stated with certainty that by the year 2000 wheat couldn't be grown north of Louisiana, the evil corporations had would use up the last of the oil so we couldn't warm ourselves, and the shipping lanes would be choked with ice. Everyone that could would move to the equator and die from malaria.
I think people don't live long enough to understand weather cycles. I also think there's something in the human psyche that predicts a doomsday---the second coming of Christ, nuclear holocaust, the superflu, global warming.
Here's what I believe. The world will still be here, with healthy people on it, thousands of years from now. Furthermore, I believe as communications improve, we head towards a global utopia. Small societies will collapse and there will be wars, but the general direction will be towards improvement. I believe studying history proves this out.