Review of "Quantifying and attributing the role of anthropogenic climate change in industrial-era retreat of Pine Island Glacier" by Bradley et al

This study applies a uncertainty quantification framework called "calibrate-emulate-sample" to the multi-centennial evolution of Pine Island Glacier.

The motivation for the "calibrate-emulate-sample" method is its iterative nature, which results in more members that agree with observations, compared to the standard Latin Hypercube Sampling plus Importance Sampling. The experimental design is very thoughtful, the manuscript is very well written and the authors do an excellent job highlighting potential caveats when necessary. The methods are clearly explained, and I was able to understand the gist of the "calibrate-emulate-sample" framework (I am not an expert in this field and thus not qualified to assess the details of the method).

Main comments:

- Focusing only on Figure 7a, one is tempted to conclude that all four ensembles explain the two observations of grounding line position equally well. This makes me wonder how robust your attribution to anthropogenic climate change really is. Are there any additional observations that could be used to further constrain the ensembles? (e.g. Sentinel images that provide the front position, observed velocities). How well does your ice sheet model reproduce reality besides retreat, e.g., velocities, dhdt?  In addition, mapping grounding line position onto a center-line is a relatively weak metric. Would you get a different result by using the floating/grounded mask and a Jaquard Score?

- You construct three emulators, one for each target (GL 1930, 2015, Volume 2015). Would your findings change if you used one emulator that predicts all three targets?

Kind regards,

Andy Aschwanden

University of Alaska Fairbanks

Minor comments:

Melt prefactor vs Sliding prefactor. The sampler seems most opinionate about these two parameters, are they strongly anti-correlated?

L 135: "which premultiplies the . $A_$..." (remove ".")

L 219 and 220: There is no Figure 2d, I assume you mean 2c.

L 343 ...by Cleary et al (2021)...

L 393 (and elsewhere) "hasn't" -> "has not"

Figure 3: "...as a function of (c-e) model and (f-h) climate parameters..." I think those are switched, (c-e) are climate and (f-h) are model parameters.