I don't. I honestly don't. It's a theory, one that hasn't been entirely proven. I do agree with the idea of "climate change" which is different from "global warming" in that not all areas will get hotter, but that the climates in different ecosystems will change and many species will be adversely affected, and some even completely eliminated. Global warming? Not so much.
But that's not even the real issue here. Even if you disagree with climate change, perhaps you might feel differently about, say, clean air? Many of the same environmental pollutants that cause climate change are also the same particulates and gases that foul our air, cause cancer, ephysema, asthma and infant deaths.
So, even if you don't give a rats ass about global warming or climate change, how do you feel about getting cancer? How big of a tradeoff is sustainable living for your family's health and happiness? We're all dying to know.