The problem as I understand it is not change of temperature. It's pretty well documented that temperatures have varried on earth since it's existence. Yeah, it's even probably better for life to flourish when it's a little warmer... Think of all the corn you could grow in the antartic for example.
And yes, climate change will transform the landscape of the planet and will destroy some habitats and create some new ones.
The real issue is that evolution, being a slow thing, life is only able to adapt if the temperature shifts are gradual as well. So the analog of what's going on today is more akin to a cataclysm (3 or 4 C in a few hundred years is as abrupt as it gets on a planet with a life span of several billion years), than a regular fluctuation of temperature that the planet would experience under "normal" circumstances... Without those changes there would have not been such a need for evolution.
But we are talking about a revolution. Revolutions are incompatible with evolution, and will lead to the world as we know it to change radically in short period of time. This puts a wrench in my hopes of a Star Trek Next Generation type peaceful, religion, money and war free future for mankind.