Environmental Governance Pressure and the Co-Benefit of Carbon Emissions Reduction: Evidence from a Quasi-Natural Experiment on 2012 Air Standards

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This is a well-conceived and rigorously executed empirical study that investigates the impact of environmental governance pressure on the synergistic reduction of carbon emissions. The authors cleverly utilize the 2012 Ambient Air Quality Standards as a quasi-natural experiment, employing a continuous DID approach to identify causal effects.  The findings are supported by a comprehensive set of checks, and provide clear and meaningful policy implications.

1. The relationship between gep, open, and pressure in Section 3.2 is somewhat ambiguous. The equation provided could be more explicit about the gep term being an interaction between a policy dummy and a continuous pressure variable.
2.  The current mechanism analysis (Table 9) primarily regresses each mediator on the treatment. While informative, this only establishes correlation and not a strict causal chain.
3.  The current policy recommendations (e.g., "strengthen the pressure mechanism", "optimize assessment indicators") are somewhat general.
4. Some figures (e.g., Figure 3) and their captions contain non-English text (e.g., Chinese labels for axes), which is inconsistent with the English manuscript format.

Comments on the Quality of English Language

This paper should be reviewed by English editor before further publication. 

Author Response

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Reviewer 2 Report

Comments and Suggestions for Authors

This paper presents a well-structured and empirically robust investigation into the critical issue of synergistic carbon emission reduction driven by environmental governance pressure on local governments. Leveraging a quasi-natural experiment and a rich panel dataset, the study provides compelling evidence on the mechanisms and effectiveness of such pressure. The topic is highly relevant, the methodology is sophisticated, and the policy implications are significant. However, several minor aspects require to enhance the paper.

1. ​​ The paper frequently mentions the "green paradox" as a counteracting mechanism but does not explicitly define how it is measured or identified in the empirical analysis beyond the theoretical model. The mechanism analysis in Table 9 shows environmental regulation intensity increases with pressure (gep), but the text (e.g., Conclusion) states this did "not expand the green paradox." This apparent contradiction needs resolution. Please clarify how the absence of a green paradox is empirically tested and verified, not just theorized.
2. ​​ The core results in Table 2 become significant only after excluding carbon trading pilot cities. The argument that the carbon market's "dominant emission reduction effects" attenuate the results requires stronger justification. Is this theoretically expected? Could there be an interaction effect? Please provide a more detailed rationale for this sample selection decision and discuss potential implications for the generalizability of your findings.
3. ​​ The core explanatory variable gepis an interaction term (time * pressure). The measure for pressure(keyword frequency in government work reports) is innovative. However, please provide more detail on the text analysis methodology: Were the reports processed for synonyms? How was word frequency normalized (e.g., by report length)? A brief discussion on the validity of this proxy beyond its correlation with ranking pressure (Fig. 2C) would strengthen the methodology section.
4. ​​ The mechanism analysis in Table 9 is valuable. To strengthen it, consider discussing the relative importance of the different channels (energy structure, industrial structure, innovation). Which mechanism appears to be the primary driver of the synergistic effect based on the coefficient sizes or potential further analysis?
5. ​​ The study focuses on city-level effects. Given that environmental policies and pollution can have spatial spillover effects (e.g., pollution moving to neighboring cities with lower pressure), have the authors considered testing for or discussing this possibility? Accounting for spatial dependence could be a valuable extension or a point for discussion. The authors should add more recently published related papers about low-carbon development and spatial spillover effects as complementary references, such as: doi.org/10.1080/09640568.2021.1945552.
6. ​​ The paper effectively uses a continuous DID to capture heterogeneity in pressure. Beyond this, were there analyses conducted on whether the effects differ significantly across city types (e.g., by region, initial pollution level, industrial base)? Such an analysis could provide deeper insights into where these policies are most effective.

 

Author Response

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Author Response File: Author Response.docx

Reviewer 3 Report

Comments and Suggestions for Authors

The paper discussed   environmental governance pressure and the co-benefit of  carbon emission reduction: evidence from quasi-natural   experiment on 2012 air standards. This is considered as  the main question addressed by the study.  The purpose of the study was to examine the reasons why  the synergistic emission reduction effect of air pollutants and carbon dioxide is not significant. However, achieving a significant reduction in air pollutants and carbon dioxide emissions is of   the utmost importance for facilitating a sustainable and environmentally-friendly societal transformation. Furthermore, the study leverages a quasi-natural experiment based on the implementation of the 2012 Ambient Air Quality Standard, employing a continuous difference-in-differences  method with a panel dataset of 250 prefecture-level cities from 2009 to 2022. The research methodology  is clear and sufficient. The findings indicate that heightened environmental governance pressure on local governments significantly reduces total regional carbon emissions, demonstrating a clear synergistic effect  on carbon reduction.

 The conclusions consistent with the evidence and arguments presented in the text and give answers about the main question. Finally,  all the references cited are appropriate.  Some additional comments are as follows:

 

1.Line 71-72:  Please give some details what do you mean with poorly designed environmental governance policies.

2.Line 84-86:   please give some details about end-of-pipe and source-based approaches. 

3.Line 111-112: The authors wrote" Environmental governance pressure, coupled with well-designed ecological and environmental policies". Please explain the method.

4. Line 173: The authors wrote" air quality information (AQI). Please give details.
5. Line 501: How do you  measure the Degree of Openness to the outside world.
6. Please give justification why the ratio of the number of students enrolled in general higher education in the region to the total population of the region at the end   of the year as control variable. In Table 1, this variable was not existing
7. Please provide a flow chat to show the clear policy implication that presented in the study.

Author Response

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Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

The structure of the article is clear and the process is explained well here. However, it could be improved in some detail.

1. The abstract is too long and not easy to follow. Moreover, the font size is small that results in inconvenience of reading.
2. The Contributions of this paper shall be enhanced. Now it is relative weak in the Introduction.
3. The literature review should be more carefully written. Some important papers have been omitted.The authors should add more recently published related papers about low-carbon development as complementary references, such as: doi.org/10.1080/09640568.2021.1945552.
4. The dissection of empirical results needs to be supplemented with more profound insights. For example, economic realities corresponding to the results should be found to corroborate them.
5. Thorough proofreading is recommended, especially the language.

 

Author Response

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