We thank the reviewer for their helpful comments, which will be very useful in revising the manuscript. Please see below for our planned changes in response to each comment:

Line 12 – “For 13 km inject,” -> “For the 13 km injection,”

Thanks, we have fixed this typo. 

Line 12-13 – This sentence reads awkward to me. I’m not sure I completely follow what is meant by “tropical cooling per unit global cooling” under a GHG warming scenario. Why is there cooling in a warming scenario – perhaps I just don’t understand this metric.

We agree this was confusingly phrased. We will revise sentence this to read as follows: "tropical temperature change per unit global temperature change is 61-75% of the equivalent ratio under greenhouse-gas forced warming"

Line 22 - The phrase “well above … quantities of SO2” could use a citation (Smith et al., 2024?)

Agreed, we will cite Smith et al. (2024) here, as suggested. 

Line 45 – Exchange the “;” for a “.”

Agreed, we will make this edit.

Line 48 – Change “68N, 10-15 km” to “68N at 10-15 km”?

Agreed, we will make this edit.

Line 100 – citation for CAM

Thanks, on second thoughts we will remove this reference to CAM as potentially confusing given our simulations use only WACCM. So the sentence would now read: The atmospheric component used for these simulations is the Whole Atmosphere Community Climate Model (WACCM6; Gettelman et al., 2019), which uses a finite-volume dynamical core and uses 70 vertical levels, up to approximately 140 km.

In Section 2.2, note somewhere that there is only 1 ensemble member for each HiLLA experiment and that they branch from the SSP2-4.5 r1. … I see “r1” written in some figures and figure captions, but I don’t believe this term is explained in the text.

Thanks, we will add this information by including the following sentence at the end of section 2.2:

"A single ensemble member is run for each simulation, and all simulations branch from the same member of SSP2-4.5. In UKESM1 this SSP2-4.5 simulation is ‘r1i1p1f2’, in CESM2-WACCM it is ‘r1i1p1f1’, and in E3SMv3 a novel control simulation following the SSP2-4.5 scenario was simulated. We refer to this background run as ‘r1’ in each case. For UKESM1 and CESM2-WACCM, we also show the ensemble range and mean in figures below, but in E3SMv3 only a single control member is available."

Figure 3 caption – last sentence: How is the ‘Antarctic’ defined?

Thanks for highlighting this omision - we will add a definition for the Antarctic area as follows: "The `Tropics', `Arctic' and `Antarctic' are defined as (23°S-23°N), >66°N, and >66°S, respectively."

Line 192 – remove “,” after the word cooling

Thanks, we will remove the comma. 

Line 223-224 – Could you explain the purpose of this decomposition, I’m not sure I follow the goal of this analysis

Thanks, yes, we will add additional explanation of the purpose here as follows: "We now decompose the global cooling per unit injection into two components: the global mean AOD per unit injection, and the global mean cooling per unit global mean AOD. This separates the effects of variation in aerosol lifetime and size distribution (which define the AOD per unit injection) from the effects of variation in the combination of SW forcing per unit AOD and temperature sensitivity to that global mean forcing, which together define cooling per unit global mean AOD (Kleinschmitt et al., 2018; Zhang et al., 2024; Duffey et al., 2025a)." 

Line 309 – Specify which relationship is “weaker”

Agreed - we will revise the sentence to specify as follows: "and the relationship between local annual mean temperature and sea-ice area is weaker."

Figure 14 Caption – last sentence, CESM_WACCM should be CESM-WACCM

Thanks, fixed. We also note (as pointed out by the 2nd reviewer) that there were a few inconsistencies throughout the manuscript in model naming (e.g. ‘CESM’, ‘CESM2’, and ‘CESM2-WACCM’ where used in different places) - the revised manuscript will use ‘UKESM1’, ‘CESM2-WACCM’ and ‘E3SMv3’ throughout. 

…

References

Smith, W., Bartels, M. F., Boers, J. G., & Rice, C. V. (2024). On thin ice: Solar geoengineering to manage tipping element risks in the cryosphere by 2040. Earth's Future, 12, e2024EF004797. https://doi. org/10.1029/2024EF004797

Please see the attached pdf.