"those who still doubt that global warming is caused by man - among them, Vice President Dick Cheney - are acting like the fringe groups who think the 1969 moon landing never really happened, or who once believed the world is flat."His arrogance is worthy of those in Galileo's opposition, rather than those who dispute the "consensus" idea as being evidence of a scientific fact.
It is easy to explain if you consider that the 1969 moon landing has occurred. That means that you can either prove it happened, or it did not happen. Global catastrophe as Gore is peddling is a prediction. Predictions are not yet proof. You can say that you have indications that support the prediction, but that still doesn't mean that it is going to happen.
But it is indicative of the weakness of his argument that he resorts to ad hominen attacks. Hey, when all else fails, call the other side stupid. You won't be right, but it will put them on the defense.