Dear Marie-Luise Kapsch and co-authors,

Due to a conflict of interest, Olaf Eisen has asked me to take over the editorial responsibilities for this manuscript. From now on I will be handling your submission.

Thanks a lot for providing detailed answers to the reviewer's comments. I now invite you to resubmit an updated manuscript in which you incorporate the changes that you mention in AC1 and AC2. Please also provide a manuscript in which the performed changes are highlighted.

Many thanks for your efforts, and looking forward to receiving the new manuscript.

Best regards,
Harry

Dear authors,

Your manuscript was reviewed again by one of the original reviewers. The reviewer was generally happy with your rebuttal and the updated manuscript and suggested a few final/minor comments that need to be addressed. Please pay particular attention to the comment regarding the albedo and density evolution sections, which should be further clarified.

Many thanks for your efforts.

Best wishes for the end of the year,
Harry

Dear Marie-Luise Kapsch and co-authors,

I am very pleased to accept for your manuscript for publication in The Cryosphere. The work is very well presented, with strong and clear visualizations, and I greatly enjoyed reading through this final version. Below, I have formulated a few final comments/suggestions, which I recommend you to consider and incorporate when submitting your manuscript for further processing.

l. 9-11: “...The increase in insolation and associated warming early in the deglaciation result in an ELA and SMB increase. The SMB increase is caused by compensating effects of melt and accumulation, as a warmer atmosphere precipitates more?”: this is an intriguing finding, which makes it quite difficult to understand for the reader (especially at this stage in the abstract). When you speak about ‘compensating’ effect, I would expect both processes kind out keeping each other in balance. But my understanding here is that the increase in precipitation outweighs the increase in melt overall (due to which the SMB increases)? And given that the ELA moves to higher elevation, do I understand it correctly that the increase in SMB mainly occurs at high elevation, while at lower elevation the SMB decreased (to a lesser extent)? As you explain elaborately in lines 396-392, this whole process is rather “counter-intuitive”. It is therefore important to be really clear in the introduction, to not immediately raise questions related to this finding. May be worth to rephrase to something like: the SMB increase occurs at high elevation (due to increased precipitation) and this effect outweighs the decrease in SMB that occurs at low elevation and causes the ELA to rise.

Several occurrences where I had to read the sentence several times before understanding it. Here could likely be solved by adding a “,” at the correct location, e.g.:
• l.30-31: had to read the sentence several times before I understood it: suggest adding a ‘,’: “...and climate change, output from...”
• l.69: “... long-term climate simulations the coupled...”  “long-term climate simulations, the coupled...”
• l.220: “For grid cells over land melt water...”  “For grid cells over land, melt water...”

l.64-65: “A thorough evaluation of the long-term model simulations and their forcing data sets used here is subject to a future study (Kapsch et al., in preparation)”: here, at the end of the introduction you start referring to future work, which you did not perform here yet. Would recommend leaving this out of introduction. A related question: in the last sentence you refer to a dataset that will be made available to the community: does this refer to the work you present here (if so, refer to ‘this dataset is made available’), or also to future work you plan to perform (if so, also best to remove this from the introduction).

In section 2.1, the subdivision of the subsections is not entirely clear: some subsections are not numbered but presented in bold (‘height correction’ and ‘surface mass and energy balance calculation’), or given in italic bold (‘Albedo’ and ‘Vertical advection and density evolution’). Would recommend numbering all the subsections (potentially introducing new subsections also), otherwise difficult to follow what belongs to what. Another option could consist of removing the all subheading without numbering. Same goes for the non-numbered sections in 2.3 and in section 3.

l.234-235: “we branched off a last millennium simulation at 950 a BP (years before present)”: without any explanation, the choice for branching off 1000 years before 1950 seems arbitrary. Why is the branching off for instance not happening 2 or 0.5 ka before 1950? Could you provide a short explanation (one or two sentences should do) why the branching off occurs over last millennium? (maybe a common approach in your field? If so, would then be good to specify this for a non-expert)

l.260: “(see Section 2.3 Nowicki et al., 2016; Fettweis et al., 2020)”  “(see Section 2.3; Nowicki et al., 2016; Fettweis et al., 2020)”

l.261: in this section, you explain that for the evaluation you rely on ERA-Interim. However, since some time now, ERA5 is out, which is from many perspective a better product than ERA-Interim, which you describe as: “one of the best reanalysis products available” (l. 266-267). Any reason for using ERA-Interim (4th generation product) and not the newer ERA5 (5th generation product)? Especially because you use the new CMIP6 data, I was also expecting to have ERA5 for the past. But maybe this is because the time period available for ERA5 was problematic? Or because ERA5 was not available at the time of analysis (like you mention for instance in earlier section at one point in l.239: “For the years beyond 2010, the forcing fields in the desired resolution were not available at the time of the analysis”). Or because MAR was also forced with ERA-Interim? I am just guessing here, so would be good to shortly mention this in text / provide a brief explanation.

l.331: ‘melt’ section: for consistency reasons, would it be possible to make a short / qualitative comparison with RACMO here in the text, as you did for the precipitation by referring to Noël et al. (2019): i.e. just include a sentence on the RACMO value that you give in Table 3, and how this compares to your model simulations.

l. 345-350: you explain some problems occurring with ERA-Interim related to e.g. an “unrealistic representation of cloud optical properties” and “low surface albedos”. Out of curiosity: do you think this is better represented with ERA-5, and would this change the outcome of your comparison? If so, potentially worth adding a comment on this.

l.353-355: long and difficult sentence to understand. Consider splitting the sentence in two to increase its readability.

l. 403: “Although melt and accumulation again partly compensate, ...”, do you mean that these two compensate one another? Maybe specify to be even clearer: “Although melt and accumulation again partly compensate one another,...”

l.414-422: here you describe the state of the ice sheet around the Holocene Thermal Maximum, but you do not explicitly refer to this period / this terminology. Any reason for this? If you think this is adequate, would support a short reference to this period, potentially including references to some studies/observations that have quantified the extent of the ice sheet during this period.

l.528: “In the future, we will utilize the EBM in...”: well, one never knows 100% how things turn out in science and what will happen. Seems really interesting, and hope you can do this, but would suggest having a slightly more conservative/tentative wording: “In the future, we plan to utilize the EBM in...”

Thank you once again for submitting your work to TC and for fruitfully interacting with the two anonymous reviewers (please acknowledge their help in ‘acknowledgments’ section also).

Best regards,
Harry