The authors have done a good job of responding to the reviewers' concerns. The authors have done a nice job of looking at the different factors which cause anomalous CO trends in models relative to observations. This should be acceptable for publication in ACP subject to minor revisions:

You make the statement that the changing balance of local v. hemispheric CO is insufficient to explain the trends in CO. I wonder if it is possible to quantify the contributions from each of these sources to the anomalous trends? At least to approximate (a) the hemispheric contribution, (b) how the mean bias applied to the averaging kernel (equation 3), (c) anomalies in Ozone, and (d) emissions might be contributing. This would strengthen the conclusions if it is possible to pull this out of your analysis. It could just be stated somewhere in a few sentences if possible.