We do not know how sensitive the climate is to CO2 yet so how can we know how much warming will result from a CO2 increase?
We have not understood all the feedbacks yet so we are not even sure if, overall, warming will be caused by increasing CO2. OK, it does in a glass tube but add carboniferous rocks, plants, clouds, thunderstorms, oceans etc, the answer may be different.
It has been warmer in the past and the temperature has changed more quickly in the past. How can we be sure that the current changes are not largely natural?
Finally, if we allow India and China to keep increasing CO2 emissions, even if the science as portrayed by the MSM is 100% correct, we will not fix anything by reducing the West's CO2 output even if we reduce it to zero. Why pretend otherwise?