Why mightn't global warning be natural? The dinosaurs died out due to changed clima, and that certainly was not because of human activities.
More cars and gas to the people.
Without the carbon dioxide produced by cars, etc, it wouldn't happen at the rate it happens. Or are you among the few who think that our last few winters (and summers) have been normal?
The dinosaurs probably died because of a catastrophic change in Earth's climate, yes, as in caused by a rock from outer space. Think of it as global warming on steroids.