Al Gore and many others believe in global warming through a process through the green house effect. Others have the theory that it, likecoming out of the ice age, is a natural warming process that the Earth has to go through after a certain period of time.
IMO, I think it's a little of both.
Yes I do believe that part of natual cosmic cycles the Earth goes through which we have no control over, but that's not to say I don't believe in a man made contribution to global warming. I don't think the level of carbon dioxide emissions we produce helps in any way, but to say that it's the sole reason for the state we are in right now is stetching it a bit. I believe I read a fact somewhere that when Mt Saint Helen's erupted in the 80's it produced more carbon dioxide emissions in
days, than humanity has ever done since the start of the Industrial Revolution.
I'm not saying to forget about it and do what you want cause it doesn't matter, I think it does. No-one likes to walk about in air filled with smog and smoke, but on the scale of things, we've probably affected the Earth much less than what the Earth does to itself.