In the first round of reviews, both reviewers raised substantial concerns about the novelty and validity of the methods and results, as well as the quality of writing, and both declined to review the revised manuscript further. The authors had regardless attempted to address those concerns to some extent, but the quality of writing was still lacking. In the second round of reviews, two other reviewers reviewed the revised manuscript; one was positive about the manuscript but their comments were too brief and unspecific to represent a full reevaluation of the quality of the paper, and, most importantly, the second reviewer in the second round was again critical of the novelty and validity of the manuscript. We therefore do not recommend the publication of this manuscript.

Reviewer #4 has raised substantial concerns about the validity and significance of the revised manuscript. We would like to request for one more round of review as we deem it appropriate to request one more reviewer to assess the manuscript, since reviewers #1 and #2 have both refused to re-review the revised manuscript.

The fifth reviewer has recommended a rejection, and raised concerns, like the previous three reviewers, about the methodological approach and assumptions behind. While we acknowledge that the authors have made an effort to address the comments from the first round of reviews, the revised results are not sufficient to convince independent referees of the value of the study. There seems to be a fundamental lack of understanding and/or of convincingly illustrating the purpose and methodology of using the drought indices to derive the presented conclusions.

The authors are given the chance to respond to the second round of reviews (#3 through #5), but are reminded that the outcome of a further revision will not necessarily lead to acceptance despite the one positive review, and that as the fifth reviewer also declined to re-review any revised manuscript, any resubmission will likely experience another delay in the manuscript processing due to difficulty in finding more reviewers.

After carefully reviewing the responses from the authors and the full revised manuscript, we agree that the authors have made a serious and conscientious effort to address the points raised by all referees. Although a few second‑round reviews maintained a critical tone, we find that most of the substantive methodological and interpretive concerns have been adequately handled in this revision. The authors have clarified the scientific scope and methodological rationale, emphasizing the study’s focus on moisture‑based hydroclimatic controls (soil moisture and evapotranspiration) rather than direct air‑pollution processes. The revised methods section now provides a more precise explanation of the counterfactual inference approach, the use of statistical significance testing, and the consistency between the “PCH” and “NP” ensembles. Issues of terminology, figure clarity, and statistical interpretation highlighted by reviewers have been substantially corrected. Importantly, the authors added clarification regarding GPP responses, demonstrating consistency between the GPP simulations and the soil‑moisture‑based drought indices, which strengthens the overall interpretation of plant productivity responses. Several textual and structural edits have also improved the readability and transparency of the manuscript.

In our view, while some critiques, particularly regarding the interpretation of drought indices and specific physical processes, remain matters of scientific judgement, they do not compromise the overall validity or utility of the study. The manuscript now constitutes a complete and well‑documented contribution that fits within the scope of Atmospheric Chemistry and Physics, offering new insight into the ecohydrological consequences of the 1991 Mt. Pinatubo eruption through a carefully implemented Earth system modeling framework.

The authors should however note that ACP now follows a rigorous guideline for the abstract and concluding section, as outlined here:
https://www.atmospheric-chemistry-and-physics.net/policies/guidelines_for_authors.html
The current abstract and concluding section have missed several elements, and the authors are recommended to revise these sections before the manuscript can be published. In particular:
- In the abstract, it does not explicitly state what was known before and how this study advances the field; it does not emphasize concrete scientific or societal implications;
- In the concluding section, an integrated interpretation beyond a summary of numerical results is recommended; the broader atmospheric–climate significance (e.g., what this means for Earth‑system functioning, carbon–climate feedbacks, or comparisons to other volcanic events) should be made more explicit; there is little discussion of how these findings affect climate understanding (e.g., coupling between radiative forcing and land hydrology), nor do they specify implications for future or larger eruptions or for climate‑geoengineering analogues.

After the abstract and concluding section are improved, the manuscript can potentially be published.