The charts show these up-down-up-down NORMAL fluctuations of just the last thousand of years.
Right now, we're at a level about half way between what the Vikings enjoyed in Greenland and what caused devastation in Europe.
Myself, I'd like to go back to a little warmer period - but truth is, there's just as much science for us heading back to another little ice age as global warming. And I don't think we're going to stop it, either way. the Earth is not a static hunk of rock - It knows what to do when. We need to learn to live with it and compensate. (And don't swallow Kyoto. That wouldn't cut down pollution one whit with China, India and all the other nations that will not be required to sign on. They will continue to pollute, increasingly, and big outfits from 'Kyoto" countries would simply move to the exempt countries.
Ergo, the same amount of pollution in the air, if not more. (Unless, of course, they can guarantee that the air from those countries will be restricted to their air space :o)
I know what caused the carbon dioxide 247 million years ago...George W. Bush!!! It was his fault! He destroyed the world then and hes in the middle of destroying it again!...LOL