Well, I'm not a climatologist, and even climatologists aren't sure what exactly is going on with the whole global warming thing, so I'm reserving judgment on this one. But when they tell me there's a 90% chance global warming is being caused by, or made more severe by, human activity, I think we ought to take them seriously. Unless, of course, we want to become experts in climatology ourselves, and I don't think you're any more keen than I am to go through the years of intensive study required to get a good grasp of the subject.