My belief is such, much like that as "Is there a God?"..." I'd rather believe there is a God and find out there isn't," than "I'd rather believe there isn't a God and find out there is." In other words, what's the harm believing global warming is due to it's humanly inhabitants and take action to protect her and one another? Even if the catastrophic effects of global warming wipes out mother earth and ourselves as we know it, at least we'll go caring about how are actions affect the earth and thus ourselves more... what can that hurt?