Well…
The IPCC/Global warming GCM models illustrate that the current ability to model climate is substandard for prediction purposes.
The range of future CO2 levels and the confidence range for GHG forcing is so broad as to be essentially useless.
The claims that more warming is bad, more CO2 in on net bad, that weather will be worse etc. are unsupportable.
The situation is that the future effects of more CO2 are so badly bounded it is like predicting an asteroid strike and not specifying if it is 1 meter or 10 kilometers.
Future CO2 levels and GHG forcing need to be more reasonably bounded and the effect of these better bounded estimates investigated before an intelligent discussion of policy can start.
It is hard to persuade someone with the argument “we think something bad will happen” and no supporting facts or details. That is where the climate change discussion is at the moment.
Right now empirical measurement and realistic assessment of future emissions would indicate that there will be a small future change due to CO2.