Review Reports

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The manuscript is excellently crafted and presents a strong argument and thorough analysis. It makes a valuable contribution to ongoing discussions about the relevance and accuracy of SDG 11, particularly in terms of urban density and land consumption metrics. The analysis and newly introduced metrics are insightful. I noticed a few editing issues in the text that can be easily corrected in lines 194, 200-201, 219-220, and 247. The manuscript is ready for publication.

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Author Response

Comment 1: The manuscript is excellently crafted and presents a strong argument and thorough analysis. It makes a valuable contribution to ongoing discussions about the relevance and accuracy of SDG 11, particularly in terms of urban density and land consumption metrics. The analysis and newly introduced metrics are insightful. I noticed a few editing issues in the text that can be easily corrected in lines 194, 200-201, 219-220, and 247. The manuscript is ready for publication.

Response 1: Thank you for the review and generous praise. The line editing issues you highlighted have been reviewed and addressed.  

 

Reviewer 2 Report

Comments and Suggestions for Authors

Dear authors, congratulations for the bold, innovative and competent approach to solve the important methodological issue of appropriate measuring the change in urban land consumption. Your work is practically ready for publication after minor proofreading, but here are some ad hoc questions which you might consider in your future work:

1. Your whole work is based on the hypothesis that there is always an increase in urban land consumption. Generally, there can be not only population degrowth, but as in some cases in Europe, a decline of the urban land consumption expressed in shrinking and even disappearing whole settlements and small towns.

2. When thinking how to interpret the values obtained for Indicator 11.3.1 with all its wide variations, it would not be appropriate to take its global or regional statistical norm for a benchmark for policy purposes, i.e. as a ‘norm’ in a policy sense – see 177 -180. Or otherwise said, the existing statistical norm of something cannot be a sufficient argument to take it as a policy norm.

3. Generally, the ‘efficiency’ of land consumption deserves also additional interpretation taking into account all the four pillars of sustainable development. But obviously, these concerns belong to the future.

    Comments on the Quality of English Language

The style is clear and the language proficiency is high; only a minor proof reading is necessary.

Author Response

Comment 1: Your whole work is based on the hypothesis that there is always an increase in urban land consumption. Generally, there can be not only population degrowth, but as in some cases in Europe, a decline of the urban land consumption expressed in shrinking and even disappearing whole settlements and small towns.

Response 1: Thanks for this comment. This is a limitation of the underlying GHS-BUILT-S dataset, and an important caveat for our results. We have added note of this limitation in lines 309-313. 

Comment 2: When thinking how to interpret the values obtained for Indicator 11.3.1 with all its wide variations, it would not be appropriate to take its global or regional statistical norm for a benchmark for policy purposes, i.e. as a ‘norm’ in a policy sense – see 177 -180. Or otherwise said, the existing statistical norm of something cannot be a sufficient argument to take it as a policy norm.

Response 2: This is a very important point. Thanks for highlighting. We made a related point in passing when presenting the regional variations in results section (lines 340-344), but this should be again emphasized in the discussion. We have done so in a new sentence in lines 458-460. 

Comment 3. Generally, the ‘efficiency’ of land consumption deserves also additional interpretation taking into account all the four pillars of sustainable development. But obviously, these concerns belong to the future.

Response 3: Absolutely. However, the scope of this article is a narrower definition exclusively focused on land consumption per capita. We have added a new sentence to recognize this limitation and make the limitation of our scope more explicit in lines 460-465. 

Reviewer 3 Report

Comments and Suggestions for Authors

The topic of this paper is interesting and meaningful. The following deficiencies require further improvement.

1. The writing of abstract is not standardized. Please rewrite the abstract in the order of "research purpose -- method -- result -- conclusion".

2. What is the research objective of this paper?

3. Compared with previous studies, what are the main innovations of this study?

4. In the discussion section, it is necessary to add the main reasons leading to regional differences in global per capita urban land consumption.

5. It is necessary to supplement the research conclusions and limitations of this paper.

6. The resolution of all figures needs to be further improved.

Author Response

Comment 1: The writing of abstract is not standardized. Please rewrite the abstract in the order of "research purpose -- method -- result -- conclusion".

Response 1: Thanks for this suggestion.  The abstract has been rewritten to put additional emphasis on research purpose and conclusions specifically. 

Comment 2: What is the research objective of this paper?

Response 2: Thanks for point out that this was not clear.  New content has been added to the abstract (lines 14-18) and introduction (lines 42-46) to clarify the research objective. 

Comment 3: Compared with previous studies, what are the main innovations of this study?

Response 3: Thanks for suggesting to state this explicitly. A new sentence has been added in lines 46-48: "To our knowledge, this is the first study to systematically compare the practicality of definitional options for Indicator 11.3.1 and the first to present an analysis of the trends of these indicators at the global scale."

Comment 4: In the discussion section, it is necessary to add the main reasons leading to regional differences in global per capita urban land consumption.

Response 4: Thanks for your interest in this question.  We are interested too.  However, this is outside the scope of this article, as it would require additional methods and research that are worth of another article. We added some additional emphasis regarding this point in the discussion section in line 457-8: "Globally, land consumption has become less efficient, on average, as well as less efficient in smaller cities and more efficient in rapidly growing ones. For the time being, we have no theory or hypotheses that would explain these differences and such questions are outside the scope of this study but are worthy of additional research."

Comment 5: It is necessary to supplement the research conclusions and limitations of this paper.

Response 5: Thanks for highlighting this deficiency. We have added content on one additional limitation in the methods section (lines 309-313: "The GHS-BUILT-S dataset does not allow for assessment of land that may be deurbanizing, as the underlying methods assume that once a pixel is built-up it stays in that state or becomes more intensely built. This prevents the application of our assessment to understanding any land trends related to urban degrowth.") and on three additional limitations in the discussion section (lines 458-467: "These statistical findings should not be interpreted as proposing a global or regional norm for policy purposes, as sustainable development needs are context specific and may call for higher or lower land consumption per capita than current levels. Relatedly, land consumption per capita is only one approach to conceptualize “efficiency” of land use (indeed, there are even many additional dimensions of urban density alone [25]), and many other dimensions of the issue may need to be considered when planning for all pillars of sustainable development, but these other dimensions are outside the narrower focus of this research. These findings, for a single period only, also give us limited insights into the shifting trends over different periods, or over longer or shorter time scales, a shortcoming for future research to address. ")

Comment 6: The resolution of all figures needs to be further improved.

Response 6: All figures have been updated with higher resolution version and in some cases additional edits have been made to make their content more easily interpretable.  

Round 2

Reviewer 3 Report

Comments and Suggestions for Authors

The authors have carefully revised this article according to my suggestions. I agree to accept it.