Dear Dr. Kemppinen,

I have read with interest the three reviews of your manuscript as well as your responses.
Based on this series of comments, I find that your manuscript may be suitable for publication in "Climate of the Past" after major revisions. It would be greatly appreciated if you could submit both a revised manuscript and a manuscript with changes highlighted, taking into account all the reviewers' comments as mentioned in your response.
In addition, it would be useful to add the Northern Hemisphere ice-sheet contour, for example as an overlay on Figure 11 (e,f).

I look forward to receiving your revised manuscript.

Best wishes,
Laurie Menviel

Dear Dr. Kemppinen,

Your manuscript went for a second round of review with the initial Reviewers. Two of the Reviewers suggest that major revisions are needed before publication. Both reviewers provide good suggestions to improve the manuscript.
Following the main criticisms, a revised manuscript would need to better synthesise the main results of the manuscript. The set-up used to simulate carbon content under ice-sheets would need to be clearly explained. In addition, the current discussion on how such a change in land carbon can be reconciled with carbon isotopes data would clearly need to be amended (e.g. p33, L. 23-25, how can lower SST and reduced marine productivity lead to a significantly lower global ocean d13C?). Finally, the figures need significant improvement, particularly figures 3, 6, 7, 11, 13, 16.
Please provide a point-by-point response to the Reviewer’s comments, indicating how you addressed the changes in the manuscript.
I am sorry I cannot be more positive at the moment, but I am looking forward receiving your revised manuscript,

Best regards,
Laurie Menviel

Dear Dr. Kemppinen,

Thank you for submitting the revised version of your manuscript entitled “Coupled climate-carbon cycle simulation of the Last Glacial Maximum atmospheric CO2 decrease using a large ensemble of modern plausible parameter sets”.
I have attentively read the responses to the referees’ comments as well as your revised version. I would be happy to accept your manuscript for publication after the points listed below have been taken into account:

1) Figures 3 and 7: Please add land contours so that the maps can be read properly. Please note that this was asked upon first submission of the manuscript, and repeated during all stages of review. If needed, please have a look at “Ferret” (https://ferretop.pmel.noaa.gov/Ferret/ ), which would allow you to plot your data and add land contours on your maps easily.

2) The exact same sentence was added at the end of the abstract and conclusion. Please modify them and please make it clearer that oxygen and carbon isotopes are not simulated here.

Other comments (lines and pages refer to the manuscript with track changes on):
- P19, L16-17: reformulate the iron fertilization part as it is not correct as is
- P19, L 24-25: As far as I know stronger westerly winds over the North Atlantic have not been put forward as a possible mechanism to decrease atmospheric CO2 over G-IG cycles.
- P21, L. 31; Please directly start as “Section 2 describes….”
- Section 2.4: When describing the different subsets, could you please add the names of the subsets in parathensis.
- P28, L.31: Please move “however” to the beginning of the sentence
- P38, L.12-14: To me, a difference of 0.1 Sv +/- 1.2 Sv indicate that there is no statistical difference between the LGM and PRE Atlantic AABW.
- P39, L. 3: Do you mean the northern limit of AABW? Why AMOC?
- P39, L. 6: please spell out “less than”
- P43, L. 9-10: I assume here you are referring to an increase in terrestrial carbon due to reduced soil decomposition. Please use this term instead of “growth of biosphere land C”
- Section 3.2.2. Please read the recent manuscript by Jeltsch-Thommes et al. 2019, https://www.clim-past-discuss.net/cp-2018-167/
- P47, L. 7: Please take out “biosphere”
- Table 4: Please add at the beginning of the legend that the estimates shown are for LGM compared to PRE. Please add estimates of Delta TerrC of Jeltsch-Thommes et al. 2019 and Menviel et al., 2017 (Paleoceanography).
- Table 5: I suppose you are referring to carbon stored under ice-sheets
- P53, L. 11: Please rephrase this sentence as its meaning is unclear.
- Figure 14: Please spell out GWS in the legend.
- P61, L. 22-23: The impact of changes in marine productivity on the global oceanic d13C is not that straightforward and would depend on the associated changes in remineralisation and burial. Enhanced accumulation of remineralised carbon in the deep ocean would lower d13C.
- Last sentence of the conclusion: please modify as stated above.

Dear Dr. Kemppinen,
Thank you for submitting a revised version of your manuscript.
I am pleased to accept your paper for publication in Climate of the Past, however some sections are currently missing and would need to be added before the manuscript can be published.
1) Please add a section on Data availability
The results of your simulations have to be deposited in a public directory.
More information is available here:
https://www.climate-of-the-past.net/for_authors/manuscript_preparation.html

Data sets: Authors are requested to follow our data policy including

- the deposit of research data (i.e. the material necessary to validate the research findings) that correspond to journal articles in reliable FAIR-aligned data repositories that assign persistent identifiers (preferably digital object identifiers (DOIs)). Suitable repositories can be found at https://www.re3data.org/;
- the proper citation of data sets in the text and the reference list (see section references);
- the inclusion of a statement on how their underlying research data can be accessed. This must be placed in the section "Data availability" at the end of the manuscript before the acknowledgements. If the data are not publicly accessible, a detailed explanation of why this is the case is required (e.g. applicable laws, university and research institution policies, funder terms, privacy, intellectual property and licensing agreements, and the ethical context of the research);
- the provision of unrestricted access to all data and materials underlying reported findings for which ethical or legal constraints do not apply.

2) Please add Author contribution: Authors are required to add a section "Author contribution" before the acknowledgements in which the contributions of all co-authors are briefly described.

Best regards,
Laurie Menviel

Dear Dr. Kemppinen,
Thank you for adding the necessary sections.
I am pleased to accept your manuscript for publication.
All the best,
laurie