The Heterogeneous Effects of Urban Form on CO2 Emissions: An Empirical Analysis of 255 Cities in China
Round 1
Reviewer 1 Report
First line in abstract, what do you mean by Urban form?
In abstract, big words like urban compactness, and urban complexity could not be understood even by researchers in urban studies. Please use plain word which can be understood by laymen easily.
p.2, Our paper speaks to the literature? This is not an English sentence.
p.3, Urban complexity refers to the irregularity of the shape of urban patches, what is urban complexity then?
p.4, our explanatory variables also speak to the literature?
Introduction is too long and lose focus. It is hard to understand what do the authors want to say. Please keep that 1.5 page only and move the remaining parts to literature review. At the end of the introduction, please state what are the remaining parts in the paper.
Move footnote to the main content and shorten the content of those in footnote.
Our study focuses on cities at prefecture level and above in China over five periods: 2000, 2005, 2010, 2015 and 2018. Why even these are not even data?
The authors should change that data to continuous from 2000 to 2022 if not 2023.
If the data is uneven like 103 cities in 2000, 154 cities in 2005, 236 cities in 2010, 231 cities in 2015, and 178 cites in 2018, why not the authors pick cities with all years’ data only?
3.2 Urban Form Metrics, what exactly is this metrics?
P7, big words like patch density (PD), landscape division index (DIVISION), splitting index (SPLIT), percentage of like adjacencies (PLADJ), and patch cohesion index (COHESION). PD equals make the whole paper very difficult to follow.
p.7, what are these “Then we obtain the false color composite images with Band 5 (Red), 4 (Green) and 3 (Blue)”?
Footnote 5, please use citation instead.
Please cite some recent published CO2 related papers: A study on the impact of fiscal decentralization on carbon emissions with U-shape and regulatory effect
3.4 heading is Panel Quantile Regression with Fixed Effects Model, but why Table 2: Notation used in FRAGSTATS algorithms?
Which method did you use?
p.13 result section is also a mess, the authors should state clear by using some headings.
There are too many variables if that regression is used instead of big data related model.
State the originality of the research gap, academic, practical and policy contributions of the paper.
Table 7’s footnote should be shortened.
Cite some more updated top journal articles as citations.
The whole paper needs much rewriting to ensure a smooth reading, now is very difficult to read.
Pack all graphics in the paper to ensure it is easy to read. This journal does not require you to put the paper to the back.
Spatial analysis and panel methods are nothing new. What is the main contribution of the paper here?
Author Response
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Author Response File: 
Author Response.pdf
Reviewer 2 Report
The paper is fine from a geography point of view. However, it theoretises too little the relationship between urban form and climate change, among other hazards. This would permit an assessment of the reproductibility of the method. For the theoretisation of the urban form there are studies in France. Specifically the relationship between urban form and hazards was studied in the RISK-UE project under the urban system exposure keywords. I recommend doing a theoretisation first of which the case study is an example.
Additional Comments:
1. What is the main question addressed by the research?
The paper addresses the question of the influence of urban form on CO2 emissions and consequently climate change.
2. Do you consider the topic original or relevant in the field? Does it address a specific gap in the field?
The relationship between natural hazards including climate change from the point of view of urban planning is little researched, although urban planning, and geography/economy which approach in this paper are social sciences and social sciences are somehow involved. But in particular also economic studies to natural hazards including climate change are rare. Also the point of view is original, starting from CO2 emissions which cause climate change and not from some effects, ex. more precipitations.
3. What does it add to the subject area compared with other published material?
See above.
4. What specific improvements should the authors consider regarding the methodology? What further controls should be considered?
Unfortunately although claiming urban form research, this comes too short. Als already said, a discussion of urban form from the point of view of urban morphology is not sufficiently done. This can be however done using the provided tools, for example different aspects of the urban texture which can be seen in GIS.
5. Are the conclusions consistent with the evidence and arguments presented and do they address the main question posed?
These are consistent with the case study and not so much with the general problem. The global context must be more emphasized.
6. Are the references appropriate?
The references are appropriate, they include both recent national and international literature.
7. Please include any additional comments on the tables and figures.
The tables and figures are suitable, well readable and well referenced.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 3 Report
The article investigates the impact of urban form on CO2 emissions and its efficiency from the perspectives of urban expansion, urban compactness, and urban complexity. Using panel quantile regression with fixed effects, the study shows that the relationship between urban form and CO2 emissions is consistent with previous literature. The partial effects of urban form on CO2 emissions are found to be heterogeneous throughout the conditional distribution of CO2 emissions and its efficiency. Additionally, the interaction effects between socioeconomic factors and urban form vary across cities with different levels of CO2 emissions and its efficiency. The findings provide insights for policy makers to optimize urban form and reduce CO2 emissions effectively.
The paper also investigates the effects of urban form on CO2 emissions and its efficiency using data on CO2 emissions, urban form metrics, and socioeconomic factors for 255 cities in emerging economies from 2000 to 2018. The mean and standard deviation values of CO2 emissions are increasing over time, indicating a general economic development but an increasing discrepancy of this development among different cities. The CO2 emissions per capita and per unit GDP show a pattern of first increasing and then decreasing, with the latter starting to decrease since 2005. The process of CO2 emissions has become much more efficient over time.
In this study there is a selection of representative indices for each categorical map pattern of urban form. The total area (TA) is used as the first main explanatory variable for urban expansion. For urban compactness, the landscape division index (DIVISION) is chosen to represent this categorical map pattern. For urban complexity, the perimeter-area fractal dimension (PAFRAC) is selected. A correlation analysis is conducted to avoid multicollinearity issues in the panel regression. All variables of urban form indices and dependent variables are in the form of natural logarithm.
The results show that urban expansion and less compact urban landscape patterns increase CO2 emissions, while urban complexity has no significant impact. The magnitude of the impact decreases at higher levels of CO2 emissions. The impact of urban complexity is larger than that of urban expansion and urban compactness on the economic efficiency of CO2 emissions. The article concludes that urban complexity has a stronger impact on CO2 emissions at low economic efficiency levels.
Overall the paper is well written: I would imporve the presentation of the equation in the footnote in page 16, it could adapted to the methodology.
Also I would compare the results with waht s available in the literature even in other related works not strictly in the field.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
The title should be changed to better reflect the content of the paper: The Heterogeneous Effects of Urban Formon CO2 Emissions: An Empirical Analysis of 255 Cities in ChinaAbstract, urban expansion, urban compactness, and urban complexity should be urban expansion, compactness, and complexity
Reference 43 please delete URL: https://0-www-sciencedirect-com.brum.beds.ac.uk/science/article/pii/ S0378778815001061
State what are the policies adopted by the Chinese government.
Section 1 Introduction still needs to tighten the contents, it seems it remains a bit losing focus.
Why China? Can the results be generalised?
Is there any figure for Figure 1 that is after 2018?
p.3, a scrutiny of is a wrong collocation?
p.3, Compact city, which is an urban form of high density, this part needs better linkage with the previous part.
p.9, why these words are capitalized: DIVISION, and SPLIT. PLADJ?
p.12, why the is added: We select the population density?
Cite some more related papers published recent year A study on public perceptions of carbon neutrality in China: has the idea of ESG been encompassed?
p.13 higher resolution figure is needed.
Figure 4, The images are composites of Band 5 (Red), 4 (Green), 3 (Blue)? What are 5, 4,3?
Section 3.4, line 2, A little is, delete A
p.13, last two paragraphs. P.14, first two paragraphs have missing citations.
Results section, “The existing empirical work finds urban formto be important determinants of the CO2 emissions. But few studies document how it impacts the CO2 emissions from an aspect of the quantile analysis. Our paper, accordingly, fills this gap by” The research gap should be stated in introduction section (close to the end), but not till section 4.
Section 4.1 title needs to be shortened.
p.15 last paragraph and 16 first line have missing citation.
Figure 5, where do the data come from? Please state the source.
4.2, landscape division index (DIVISION) and splitting index (SPLIT) need more explanation about what these are.
4.2.1, what do you mean by Distributional Effects?
Data summary is needed.
p.21 and 22, shorten the note please.
Pack footnotes to the main paragraph.
p.25, note is too long
Add some heading before the section of conclusion, it is quite difficult to read and catch the main meaning of the paragraphs now.
Urban form needs a separate section to state what exactly that is.
Limitations and future direction should be added in conclusion.
Data summary of 255 cities Table should be added.
Author Response
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Author Response File: 
Author Response.docx
