Before acceptance of this preprint as an ACP Letter, as Executive Editor I requested that the authors clarify that that the approach they have taken to estimating ERFaci is only one of several others. Several other studies have applied multiple constraints simultaneously and reached different conclusions about the tightness of constraint. Reliance on one or a small number of constraints might lead to over-constraint, which I was concerned may be the reason for the overly tight constraint that is presented. In particular, ignoring conflicting constraints can lead to over-constraint. I requested that the author make clear that the tightness of constraint is inconsistent with other approaches in which a larger number of constraining observation types are used. Based on those alternative approaches, a larger uncertainty range remains plausible. Based on the added text drawing comparisons with previous similar and alternative studies, I am happy to accept it as a Letter based on the novelty and advancement in our quantification of aerosol radiative forcing.