Here's how I see it.
On the one hand, there's the possibility that global warming really is influenced by us and we've contributed a lot to its acceleration. No matter what we and the rest of the First World do in trying to save the world, China, India, and the rest of the industrializing world will fuck it up. In a matter of decades, the world's air and water is going to be so fucked that it will likely decrease our species' overall lifespan due to things like disease and deformity.
On the other hand, if it's all bullshit and completely cyclical, then the warming of the planet is beyond our control and a slow enough process that we'll all be dead by the time the shit really hits the fan. I feel sorry for our descendants, but hey, we can each do the world a favor, and don't bring any kids into this fucked world.
So, there you have it. Enjoy life now for what it is, and hope that you die before it gets too bad.