Fu*k the dinosaurs. I am not a conservationist, I care about human life. And as many studies have shown (I have only read the Stern Report) increasing average temperatures will overall not be benefical to us. As you said there is a large lag in the system so it is truly a long-run issue.
Of course the distribution isn't even, Greenland might very well become actually green and other cold places become more hospitable to humans (not that Scandinavia is a bad place to live, it's actually one of the best places in the world) but hot places becomes less hospitable or even totally unlivable. Shallow places like islands or Netherland/Belgium might vanish. And there's the extreme weather thingy which has impacted food prices this year. If you are a Westerner a 10% increase in food prices matters little if you only spend 10% of your income on food, that's just a drop of 1%, but if you are a poor fu*k in the third world food scarcity is a life and death issue.
The sad irony is that the First World which emits most per head (and has emitted most per head if you view not merely the flow of emissions but also the stock of CO2 etc in the atmosphere) can fairly easily hedge itself against these risks (Europe might even become colder first if the Gulf Stream stops).
So we are screwed no matter what. If you as well as the scientists who view CO2 emissions as minor cause of global warming are right then we cannot counteract it but it also might not skyrocket as much as mainstream science indicates.