@Wazikashi: fire, the red flower , can devastate forests quite fast. I think the wood used wasn't really wood but coal, so I should have clarified that I meant that these trees weren't necessarily chopped down, but sometimes also burnt down. Still, there's the same important phenomenon we get back to - sometimes a small action from humans alters a balance so that nature itself causes things to spiral away into much more than we had intended, or were responsible for.

The triassic jurassic and mesozoic eras were indeed hotter, there was very little ice etc. Since then, much of the coal and what later became fossile fuels was bound into the earth, allowing a lower temperature. The problem is that we are trying to take up more coal and fossile fuels from below ground than the amounts that were in the air during these periods.