A Scenario Simulation Study on the Impact of Urban Expansion on Terrestrial Carbon Storage in the Yangtze River Delta, China

Round 1

Reviewer 1 Report

- The subject addressed is within the scope of the journal.

- The abstract could become much better if it properly introduces the study from a research standpoint. Also, the main findings could be stated more pointedly in the abstract.

- This paper selects research area of Yangtze River Delta, China, why do you choose this region? What are the differences between  this  region  and  other  regions  in China? What is the benefit of selecting this region for this experiment?

- However, the manuscript, in its present form, contains several weaknesses. Appropriate revisions to the following points should be undertaken in order to justify recommendation for publication.

- Page 8: the following paragraph is unclear, so please reorganize that:

“In contrast, DOC decreased the least to 0.699 Tg, accounting for only 5.298% of the loss of TCS. The annual growth rate of all urban areas decreased, with Shanghai, Suzhou, Nantong, and Nanjing increasing their urban areas by 53, 48, 41, and 87 km2 respectively. Affected by urban expansion, Nanjing's TCS loss in 2030 far exceeded that of Shanghai, Suzhou, Nantong at 0.493 Tg. AGC, BGC, SOC, and DOC decreased by 0.081 Tg, 0.074 Tg, 0.313 Tg, and 0.025 Tg, respectively.”.

- Can the use of other methods presented in some studies improve the accuracy of the results to an acceptable level?

- It is suggested to add articles entitled “Kadhim et al. Urban Landscape Fragmentation as an Indicator of Urban Expansion Using Sentinel-2 Imageries” and “Albasri et al. Prediction of Urban Spatial Changes Pattern Using Markov Chain” to the literature review.

- Some key parameters are not mentioned. The rationale on the choice of the particular set of parameters should be explained with more details. Have the authors experimented with other sets of values? What are the sensitivities of these parameters on the results?

- Conclusion:

•The conclusion section is currently a repeat or rehash of the preceding sections, and  needs to be re-written to improve it, keeping in mind the following suggestions.

•Update the conclusion to include the newly formulated theoretical contributions

•Mention the limitations of the study and prospects for future research.

•Summarize the key results in a compact form and re-emphasize their significance.

•This conclusion could be worded in a manner as to emphatically motivate the academic community to get down to actionable, practical engaged scholarship.

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

Please refer to the attachment.

Comments for author File: Comments.pdf

Author Response

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Author Response File: Author Response.docx

Reviewer 3 Report

This paper focuses on the effect of the urban expansion on terrestrial carbon storage in the Yangtze River Delta. Urban expansion is extracted from the 2000 and 2010 maps from GlobalLand30 through PLUS model; Terrestrial carbon storage is measured by the Carbon module of the InVEST model. Results show that the impact of urban expansion on terrestrial carbon storage is significant.  The author's model selection and application are solid. The relevant description is also very detailed. 

Major issue:

1. Some of the details are not quite related to the main topic. I'm not surprised that urban expansion will occupy agricultural land and thus cause carbon sink reduction. Whether it is necessary to discuss carbon sink reduction by category?

2. Some content needs to be rewritten. For example, "Slope and general road" are the two main drivers that the authors concluded. However, figure 5 provides more drivers. As I see, priority expansion in areas with convenient transportation (road, highway, railway and even river). The authors should reasonably explain the research results and fully reflect the research value in the conclusion. To be more professional!

Minor issues: none.

Author Response

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Reviewer 4 Report

I would like to thank the authors for the interesting and relevant research. Please find some comments for the improvement of the article below.

1.     At the end of the introduction, I suggest presenting the structure of the article.

2.     There is a lack of deeper theoretical substantiation.

3.     The authors should present the results of previous similar studies in more detail.

4.  I propose to present the research results in chapter 3, and to present the discussions in chapter 4. I propose to present the conclusions of the study in chapter 5.

Author Response

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Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

The article has been revised very well, so I would suggest to accept in its present form.

Reviewer 2 Report

I suggest that this paper can be accepted  in this version.