Review Reports

Round 1

Reviewer 1 Report

The manuscript entitled “How does the population structure changes of China affect carbon emissions? An empirical study based on ridge regression analysis” analyzes the relationship between carbon emissions and population size, age structure, consumption structure, and employment structure. The procedure of data analysis is quite standard, and the results are in general reasonable. I only have few comments on the manuscript.

Lines 16-18: I would explain the implications of these positive/negative values here.

Lines 58-59: Unclear what the “long-run equilibrium relationship from population to carbon dioxide emissions” is.

Section 2.2: The authors gave a good literature review here but failed to provide the rationale.

Line 168: “we took the logarithm of both sides of the model at the same time.” – this would yield lnY = ln(β0 + β1X1 + β2X2 + β3X3 + β4X4 + μ).

Table 1: The authors selected only one variable to represent population age structure (consumption structure and employment structure). Will such selection influence the results? Are the results robust enough to different variables to support the conclusion?

Lines 195-197: “If the Engel coefficient decreased”, will carbon emission decrease or increase?

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

The comments are reported in the attached file

Comments for author File: Comments.pdf

Author Response

Response to Reviewer 2 Comments

Dear reviewer:

Thank you very much for reviewing the paper and the constructive comments on the paper. Your suggestions helped us regulate the details of the paper and inspired us a lot. Based on your suggestions, we made a further revision targeting to adjust article much reasonably. All of changes were clearly highlighted by using the “Track Changes” function in Microsoft Word. The specific revisions and responses are as follows:

Point 1: In order to complete the analysis, also consider the mitigation aspects discussed in the study: Mitigation strategies for reducing air pollution.

DOI: 10.1007/s11356-020-08647-x

Response 1: According to your suggestion, we have added the mitigation aspects in the study. (lines 186-188).

Point 2: Format the table correctly

Response 2: As suggested, we have formatted the Table 1 correctly. (line 214)

Point 3: Clarify this coefficient better

Response 3: Thank you for your suggestion, we have clarified the coefficient in more detail. (lines 264-267)

Point 4: Format the table correctly

Response 4: As suggested, we have formatted the Table 2 correctly. (line 276)

Point 5: Implement an exponential annotation

Response 5: As suggested, we have redrawn the figures and readjusted the units of measurement. (lines 295-297)

Point 6: Format the table correctly

Response 6: As suggested, we have formatted the Table 4 and Table 5 correctly. (line 350, line 355)

Point 7: Improve the general quality of the image, in particular: -reduce the zeroes on the axes-enlarge the writing.

Response 7: As suggested, we have improved the general quality of the image, reduced the zeroes and enlarged the writing. (lines 379-380)

Point 8: Format the table correctly

Response 8: As suggested, we have formatted the Table 8 correctly. (line 384)

In the end, we sincerely thank you again for the valuable suggestions. We look forward to discuss with you again so that we could make further amendments and improvement to our research.

Reviewer 3 Report

DEar Authors,

The paper entitled "How does the population structure changes of China affect carbon emissions? An empirical study based on ridge regression analysis" is rigorously written and presents some interesting results. It could be accepted after some minor revision about english language and style. Please correct them.

Author Response

Dear reviewer:

    Thank you very much for reviewing the paper and the constructive comments on the paper. Your suggestions helped us regulate the details of the paper and inspired us a lot. We sincerely thank you again for the valuable suggestions. We look forward to discuss with you again so that we could make further amendments and improvement to our research.