For temperature rise on the low side of the range...
It looks like it may lead to a net increase in food production, but the distribution will be different. IF kansas and nebraska become dustbowls, but siberia more than compensates for it, is that an acceptable change for you?
Droughts and their scale are predicted to increse, as is flooding... this will hurt developing nations the hardest.... we have already seen occasional famines and the instability they bring- are we served by their becoming more common?
You can say climate changes have happened before to humans, and you are right- but changes like what we are anticipating have not happened when we are so reliant on the status quo.