Optimization of Land-Use Structure Based on the Trade-Off Between Carbon Emission Targets and Economic Development in Shenzhen, China
Round 1
Reviewer 1 Report
This is a very good paper. However, I would see a more explicit explaination on the use of the optimization model adopted in this paper. What is the relevance and applicability to different case studies and more generally to case studies at the larger scale (continental, global). The application proposed here is important, but should be conceptualized better to a wider spatial and temporal scale. The issue of land-use change over time should be incorporated in the model or at least commented more clearly in the discussion section. The state of the art of this paper can benefit from these approaches and can improve quality and readability of the discussion section.
I suggest also to enlarge and enrich the conclusion section.
Author Response
On behalf of my co-authors, we thank you very much for giving us an opportunity to revise our manuscript, we appreciate it very much for your positive and constructive comments and suggestions on our manuscript.We have revised the manuscript according to your kind advices and referee’s detailed suggestions.Some of your questions were answered below.
Point 1: This is a very good paper. However, I would see a more explicit explanation on the use of the optimization model adopted in this paper.
Response 1: Thank you very much for the insightful suggestions and kind appraisal to it as a very good paper. According to the comments, the more explicit explanation on the use of the optimization model has been added exactly in this revised manuscript. Under different scenarios in 2020 and 2025, we mainly adopt the multi-objective linear programming model to optimize the land-use quantity structure. This study suggested to adopt simulation results under the low-carbon economy scenarios in 2020 and 2025. The natural scenario could be applied to monitor the possible rapid changes in land use that the government needs to prevent. Also, the simulation results of the low-carbon scenario, as the most ideal target for low-carbon urban development, can be used to examine the current situation of the land-use structure. What’s more, the optimization model would provide some thresholds of land-use changes for a sustainable path to the future development, which have been added to the discussion part.
Point 2: What is the relevance and applicability to different case studies and more generally to case studies at the larger scale (continental, global). The application proposed here is important, but should be conceptualized better to a wider spatial and temporal scale.
Response 2: Sincerely thanks for the reviewer’s insightful comments. In Discussion part, the extension notes of the method have been added in the revised manuscript. According to carbon emissions for a typical year under the guidance of IPCC in Shenzhen City and the economic benefit coefficients of the various land use types, this study used a MOLP model to optimize land-use structure under different scenarios by setting the local target functions and constraint conditions. This research has been conceived in such a way that the approach can be easily extended to other regions. There is uncertainty in the target functions and constraints in the MOLP model. Therefore, in different case studies, according to the local carbon emissions and development goals, we should further modify the model in order to obtain an optimization scheme for the study area. When this approach is extended to a wider scale, the localization of the objective functions and constraints in the model can also be readjusted in detail. Modification based on the local conditions could help extend the model to a wider spatial and temporal scale.
Point 3: The issue of land-use change over time should be incorporated in the model or at least commented more clearly in the discussion section. The state of the art of this paper can benefit from these approaches and can improve quality and readability of the discussion section.
Response 3: Thank you very much for the instructive and kindly comments. In our study, we defined land as the carrier for the carbon emissions. However, the annual carbon intensity of various land use typess may differ from those in 2016. To discuss this issue, we have modified the discussion part according to your suggestion. In the future research, we would attempt to apply the mean of the long-term annual carbon intensities of various land use types to reduce the impact of annual land-use change.
Point 4: I suggest also to enlarge and enrich the conclusion section.
Response 4: Thank you very much for the instructive comments. According to the comments, the content of the conclusion section has been enlarged and enriched in the revision. For example, in conclusion part, we have added the important results about the annual intensity of carbon emission of different land-use types, as follows: ‘Under the guidance of IPCC, the calculation results of the intensity of carbon emission of farmland, woodland, grassland, water areas, shallows, build-up land, and other land are as follows: 5.13 t C·hm-2·a-1, -0.26 t C·hm-2·a-1, 22.42 t C·hm-2·a-1, 1.10 t C·hm-2·a-1, 240.42 t C·hm-2·a-1, and 0.76×10-3 t C·hm-2·a-1.’
Author Response File: 
Author Response.docx
Reviewer 2 Report
The paper entitled “Optimization of land-use structure based on the trade-off between carbon emission targets and economic development in Shenzhen, China” presents an in-depth assessment of the possible target reduction of the total carbon emissions due to land use change scenarios analysis. Results are based on a comparative analysis of cumulative emission for each land use scenario, and the methodology takes the land use as a proxy of the total carbon emissions. This approach is well-developed in the international bibliography, and land use regression analysis is the standard approach to determine the total carbon emissions at different scales, using the land use associated to a specific emission factor to determine the total amount of air pollution.
I found the article interesting since this approach to determine the air quality from land use emission factors is less analysed than another kind of land use change effects. I wonder what in the article less attention is dedicated to the Ecosystem Service air quality assessment, which in this specific field is a bit missing the possibility to use specific software that use the land use a proxy of air pollution and measure the sustainability of a different scenario. I suggest to the authors to take into account the CICES classification of ES and see that air quality is considered one of the most important functions that are generated at the landscape level and guarantee a healthier condition for citizens.
Overall, I found the article well-written and well-designed. I don’t see substantial flaws of weak points, and English is good. The readability is high and even if the methodology is easy-to-understand and immediately comprehensible also for a non-expert reader.
I can suggest to the authors to consider, in the discussion, to highlights some thresholds of land use changes that guarantee the sustainability of emissions in future. For example stating how much is possible to augment the built-up system reducing another kind of uses to deliver a sustainable future, or how much land for compensation is needed to balance the potential increase of urban futures to reach sustainability. This helps the reader to keep clearly in mind which is the threshold for a sustainable path to the future development.
I also suggest declaring in the paper on the base of what the land use change scenario is drive (I mean natural, low carbon and low carbon economic are contradishtigued by?)
Hereafter some minor mistakes
Line 38 space after [1] see also lines 43, 48, 53, 57, 66, 69, 116, 260, 264, 300
I suggest (line 269) to use the comma to separate numbers (100,400.00)
I suggest reading the text carefully to avoid little mistakes. Nonetheless, I strongly recommend the publication for this paper.
Author Response
Dear Reviewers:
Thank you for your comments concerning our manuscript entitled “Optimization of land-use structure based on the trade-off between carbon emission targets and economic development in Shenzhen, China”. (ID: sustainability-400108). Those comments are all valuable and very helpful for revising and improving our paper, as well as the important guiding significance to our researches. We have studied comments carefully and have made correction which we hope meet with approval. Revised portion are marked in red in the paper. The main corrections in the paper and the responds to your comments are as flowing:
Responds to the reviewer’s 2 comments:
Point 1: I found the article interesting since this approach to determine the air quality from land use emission factors is less analysed than another kind of land use change effects. I wonder what in the article less attention is dedicated to the Ecosystem Service air quality assessment, which in this specific field is a bit missing the possibility to use specific software that use the land use a proxy of air pollution and measure the sustainability of a different scenario. I suggest to the authors to take into account the CICES classification of ES and see that air quality is considered one of the most important functions that are generated at the landscape level and guarantee a healthier condition for citizens.
Response 1: Thank you very much for the insightful suggestions and kind appraisal to it as an interesting work. According to your comments, we re-considered the framework in this study, and your suggestions provide a new perspective to our future research. In our study, we firstly calculated carbon emissions of the typical year under the guidance of IPCC (Intergovernmental Panel on Climate Change). Based on the greenhouse gas inventory of IPCC, sources of the total carbon emissions are usually divided into four sectors: 1) energy consumption, 2) industrial process, 3) forestry, agriculture, land use, and land use/cover change (LUCC), and 4) waste. The IPCC method mainly focuses on the estimation of carbon emissions from surface natural and anthropogenic activities. And our study defined land use as the carrier for carbon emissions. What’s more, according to your great suggestion, our future work could consider expanding up to multiple pollutant gases and analysing the change of their ecosystem services based on the common international classification of ecosystem goods and services (CICES).
Point 2: I can suggest to the authors to consider, in the discussion, to highlights some thresholds of land use changes that guarantee the sustainability of emissions in future. For example stating how much is possible to augment the built-up system reducing another kind of uses to deliver a sustainable future, or how much land for compensation is needed to balance the potential increase of urban futures to reach sustainability. This helps the reader to keep clearly in mind which is the threshold for a sustainable path to the future development.
Response 2: Sincerely thanks for the reviewer’s insightful comments. In Discussion part, the thresholds of land use changes have been reorganized exactly to make it clearer in this revision. Some thresholds of land-use change are shown as follows. According to the optimistic results, by 2020, built-up land was allowed to increase by about 2,554.48 hectares for a sustainable path to the future development. A limited amount of built-up land is expected to be used for urban construction limitation to achieve the goals of land consolidation and functional concentration as much as possible. Approximately 792.00 hectares of other land use types can be converted into built-up land. By 2025, built-up land was allowed to increase by 6,225.02 hectares compared to that in 2016. In addition, woodland needs to increase by at least 1,652.95 hectares and water and shallows by 1,027.88 hectares to counterbalance carbon emissions and urban economic development.
Point 3: I also suggest declaring in the paper on the base of what the land use change scenario is drive (I mean natural, low carbon and low carbon economic are contradishtigued by?)
Response 3: Thank you very much for the instructive comments. According to your comments, the content of the land-use change scenarios has been reorganized in the revised manuscript. We designed three development scenarios to predict land use structure in 2020 and 2025. Firstly, the natural scenario only considered land demand to promote urbanization and economic development, and in which the change trends of the various land-use types were based on the rate of land-use change during 2012-2016. If the government cannot manage or control properly, land-use structure has great potential to develop in this direction, which would hinder the sustainable development of the city. Secondly, the low-carbon scenario, aimed at reducing carbon emissions, was an ideal target for maximizing low carbon development. Last but not least, the low-carbon economy scenario took the requirements of low-carbon targets into account to achieve maximum economic development.
In summary, the above three scenarios are simulations of future land-use development. And we recommend that decision makers adopt simulation results under the low-carbon economy scenarios in 2020 and 2025. Meanwhile, the natural scenario could be applied to monitor the possible rapid land use change that the government needs to prevent. Also, the simulation results of the low-carbon scenario, as the most ideal target for low-carbon urban development, can be used to examine the current situation of the land-use structure.
Point 4: Hereafter some minor mistakes
Line 38 space after [1] see also lines 43, 48, 53, 57, 66, 69, 116, 260, 264, 300
I suggest (line 269) to use the comma to separate numbers (100,400.00)
I suggest reading the text carefully to avoid little mistakes.
Response 4: Thank you very much for the meticulous and kindly comments. According to your suggestions, in the revised manuscript, we have corrected all the mistakes you pointed out. For example, some typical mistakes have been corrected as follows:
Line 41-42: “China, as the largest developing country, joined the Paris Agreement in September 2016 [5].”
Line 261-263: “Considering the rapid development of the economy and land use, it was assumed that 75% of the target 20,669 hm2 would be achieved by 2025, and the upper value was increased according to the lower value (Table 2).”
Line 266-267: “The upper value is 100,400.00 hm2, which is available from the Shenzhen Land Use Plan 2005–2020.”
Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
I think the revision is going in the right direction.
A thorough revision aimed at improving the language usage is the last task to be performed to have published this paper.
Author Response
Dear Reviewers:
Thank you for your comments concerning our manuscript entitled “Optimization of land-use structure based on the trade-off between carbon emission targets and economic development in Shenzhen, China”. (ID: sustainability-400108). We thank International Science Editing ( http://www.internationalscienceediting.com ) for editing this manuscript and have made correction which we hope meet with approval.
Author Response File: Author Response.docx
