Dear Franka and co-authors,

Thank you for submitting your point-by-point replies to the reviewer comments. Both reviewers requested minor revisions, which I think you have comprehensively addressed in your replies. I would like to invite you to upload a revised version of the manuscript at your earliest convenience, taking into account all the comments raised by both reviewers, preferably implemented as tracked changes.

All the best,
Jan De Rydt – topical editor

Dear Dr Jesse and co-authors,

Thank you for submitting a revised manuscript, and my apologies for the delay in handling your submission. I believe most reviewer comments were addressed in a comprehensive way, and the manuscript is close to being ready for publication. When going through the revised text I did pick up a few minor points, however, which I would like you to consider before submitting the final version. They are listed below, with line numbers now referring to your revised text with tracked changes. I would like to thank you for choosing The Cryosphere to publish your work, and extend my sincere thanks to Xylar Assay-Davis and Rupert Gladstone for their excellent support.

Best regards,
Jan De Rydt - topical editor

===========================
L440-445: Melt-driven retreat down a retrograde slope should not be confused with MISI. To show MISI, as done by e.g. Rosier et al. 2021 and Reed et al. 2024, a dedicated set of experiments is needed to demonstrate that no stable locations of the grounding line exist. In fact, Gudmundsson et al. 2012 showed that for this domain and geometry, the grounding line can be stable on the retrograde slope.

L533-540: You currently allow the ice thickness to become zero in originally ice-covered regions, at least in LADDIE (also in IMAU-ICE?). You could test the sensitivity to this choice and preserve the heat and momentum all the way to the ice front by imposing a minimum ice thickness in both models. I’m not suggesting this as an additional simulation for this paper, but it could be something to look at in the future.

L565-575: Although the reviewer has asked for cross sections of ice draft and a discussion about the sensitivity of the basal slope to the choice of basal sliding law, I’m not sure how much you can say about that without doing simulations with different sliding laws. The statement “In contrast to power-law sliding laws such as that of Weertman (1957), the Coulomb-limited Schoof sliding law used in our study yields stronger surface gradients across the grounding line, which may influence the melt–geometry feedback.” either needs a reference or should be shown explicitely from model simulations with different sliding laws. I’m not sure why one would expect “a flatter draft … under power-law sliding”.

L601 and following: how do you define and diagnose buttressing here? Do you look at the instanteneous change in the velocities when ice is removed?

References

* Gudmundsson, G. H., Krug, J., Durand, G., Favier, L., and Gagliardini, O.: The stability of grounding lines on retrograde slopes, The Cryosphere, 6, 1497–1505, https://doi.org/10.5194/tc-6-1497-2012, 2012
* Reed, B., Green, J.A.M., Jenkins, A. et al. Recent irreversible retreat phase of Pine Island Glacier. Nat. Clim. Chang. 14, 75–81 (2024). https://doi.org/10.1038/s41558-023-01887-y
* Rosier, S. H. R., Reese, R., Donges, J. F., De Rydt, J., Gudmundsson, G. H., and Winkelmann, R.: The tipping points and early warning indicators for Pine Island Glacier, West Antarctica, The Cryosphere, 15, 1501–1516, https://doi.org/10.5194/tc-15-1501-2021, 2021