There's alwas the possibility....
While we humans are very good at trying our damdest to bugger-up the ecology of this planet, whether it be poisoning the sees (not that it matters any more because we've dragged out and and/or killed anything and everything that actually lived in there), raping the rain forests, over-farming fragile local ecologies and turning them to desert, throwing toxic waste all over the place, and pouring oil into the sea, etc etc, it might just be that the planet is actually more robust when it comes to the climate. Could it be that if it wasn't, then we probably wouldn't be here in the first place?
Oh, hang on - where's the tax revenue opportunities with that way of thinking?