The climate has changed before - so what?

Over at Skeptical Science, they have posted a simple, easily digested explanation of the climate we have evolved in response to. It seems our species has experienced a couple of colder periods - glaciations - but we have never been through a climate hotter than we experienced last century. As we are set fair to warm the planet with our CO₂, it is sobering to realise that we are heading into uncharted waters and there is no way back. We are committed and all we can do now is hang on for the ride. Such fun.