Dear authors,
In the view of the previous interactions we had where I requested a side-by-side handling of your two companion papers, ms. gmd-2015-140 has received a new review that have some bearing on both manuscripts. I thus copy that new review here below as well as my comments in the non-public section.

Best wishes,
Didier Roche

Review received:

I have now read the revised version of Law et al., as well as the response of the authors to the earlier referees’ comments. In addition, I have read the companion paper of Ziehn et al., also in discussion in GMD.
I’d like to start by stating that the material presented in these 2 paper (description of the model, comparison to observations, intercomparison to other CMIP5 models) is clearly very well suited for GMD, and could indeed be presented in 2 companion papers, as proposed here by the team of authors. In addition, I’d like to assert that concentration-driven simulations are suitable enough to evaluate the carbon cycle components of an ESM. To my view, it is not a shortcoming not to have emission-driven simulations.

That said, I have a few reservations that prevents me to recommend acceptation of the present manuscript (Law et al.) in its actual form.
Whereas I find Ziehn et al. quite well balanced between ocean and land carbon cycle components, it is clearly not the case for the Law et al. manuscript. Here are a few obvious examples :
- a clear focus on evaluation for the ocean vs. sensitivity tests / variability for the land carbon.
- as well, the analysis of the quasi-equilibirum for the carbon cycle components is done very differently for the land and for the ocean.
- on a a less important note perharps, the figures are also not homogeneous at all between the land / and ocean sections.

Overall, this gives the impression of a merge (ocean + land) without much smoothing of 2 sub-studies.

If the authors go on with 2 companion papers, one focused on pre-industrial, the other one on the historical simulation, I would clearly recommend to revise the first one by Law et al. to propose an homogenized approach of the ocean and land carbon cycle. The evaluation part could be moved in the second paper (historical + evaluation), the first paper (Law et al.) focusing on a detailed description of the model, on the equilibration of the carbon cycle, and on sensitivity tests / natural variability.

Dear Tilo Ziehn,

I am happy to accept the manuscript for final publication.

Thanks for your patience and for submitting your work to GMD.

Best wishes,
Didier (Roche)