George E. P. Box said that all models were wrong, but some are useful.
I wouldn’t include the AGW/CC models in the “useful” category, except as a political tool for political tools.
Maybe as useful as “horseshoes and hand grenades” yet the models have to be precise otherwise the results are garbage — your note about AGW.
Then additional accuracy is lost when they digitize a nonlinear model (an approximation, in the first place) to make it compatible with a computer simulation. Compound this with the thousand of variables each with their own nonlinearities, plus not clearly understanding the feedback and feed-forward mechanisms of the system and the interactions between the variables and initial conditions having gross error, and your simulation is garbage. Sorry, ranting about AGW again....