You're taking a human centric view here. As misanthropic as it may sound, it's entirely possible that this is just a correction in the tiny fraction of the great span of geologic time we happen to be living in. Similar to how the human body gets a fever to fight off an infection, we have the earth heating up to a level destroys the destructive pathogen - us.

I suppose it's possible that we get wise enough to deserve continue on as a species, but at this point I doubt it. I don't see anything in humanity that would lead me to believe it's capable of making the cohesive decisions to remedy the situation. Something else will come along in a few million years and maybe they'll do a better job of it.