An Index-Based Assessment of Perceived Climate Risk and Vulnerability for the Urban Cluster in the Yangtze River Delta Region of China

Round 1

Reviewer 1 Report

The paper creates the Index-based climate risk assessment method to assess the climate risks for cities in the Yangtze River Delta, which demonstrated a meaningful approach in urban climate studies. However, it is certainly not the first index-based approach in this study field. The literature overview is very weak. The paper must identify clearly what’s the difference and added value of this study to existed research. Acknowledging the strong effort put in by the authors, the reviewer would suggest considering the manuscript after a major revision. The detailed comments are given as follows.

 

It would be better to use “urban cluster” rather than “city cluster” in the title.

After reading the paper, it is clear that the climate risk assessment is strongly based on interview data from experts and stakeholders. Thus the climate risk is “perceived risk” from people’s experience, knowledge, and feelings.  Physical climate and environment data are very limited in this study. The authors must introduce this clearly in title, abstract and main texts.  

The literature support is very weak. First of all, what have been studied regarding climate risk assessment? There are huge amount of papers assessing climate risk and many methods were used, including index-based methods. Why is this study valuable? what is the added value of this study regarding the index method?

Second, why do you choose cities not rurals? What are the general climate risks in urban clusters at other countries and regions? Why do you choose the Yangtze River delta? What are the unique characteristics of the area?  These must be evidenced with literature review in the introduction of the paper.

·         Carlos Tapia, et al. Profiling urban vulnerabilities to climate change: An indicator-based vulnerability assessment for European cities. Ecological Indicators. Volume 78, July 2017, Pages 142-155. https://doi.org/10.1016/j.ecolind.2017.02.040

Liang Yang, et al., 2015.      Climate-related Flood Risks and Urban Responses in the Pearl River Delta,      China. Regional Environmental Change. 15(2):379-391. DOI:      10.1007/s10113-014-0651-7

 

There are already huge amount of papers assessing climate risk in city areas, including heat wave, air pollution, floods, and typhoons. And, some studies also concluded that urbanization can benefit living environment in cities. So, what is the added value of this study regarding urban climate risks?

·         Liang E. Yang, Peter Hoffmann, Jürgen Scheffran, 2017. Health impacts of smog pollution: the human dimensions of exposure. Lancet Planetary Health, 2017,1(4):e132-e133.

·         Xiaoqing Song, Kang-tsung Chang, et al., 2016. Change in Environmental Benefits of Urban Land Use and Its Drivers in Chinese Cities, 2000-2010. International Journal of Environmental Research and Public Health,13(6):535. doi:10.3390/ijerph13060535

 

Section 2, there needs a map of the studied cities in the Yangtze River Delta. YRD covers 26 cities, why do you choose only the 6 cities, which 6 cities?

Are the experts asked to score all the 5 infrastructure sectors for the 6 cities? If yes, how reliable is it if an expert of transportation scores water infrastructures? If not, how could it be comparable and how did you integrate the various assessments of different experts on different infrastructure sectors?

Even in one infrastructure sector, e.g. transportation, an experts on subway systems may know very few about port terminals or airport systems. Also, hospital expert may know nothing about police and schools. How could the experts evaluate them?

Among the 67 experts, how many of them come from each of the 6 cities? How many of them can represent each infrastructure sectors?

The authors didn’t consider adaptive capacity in risk assessment, which is a big deficit of the paper. Actually, different groups of people have different capabilities to cope with climate impacts, thus their perceived risks are different. The interviewed experts may have higher education level and income level, thus their risk assessment may not represent the risks of poor people. I guess it is very difficult for the authors to consider this issue in the present paper, but at least this must be discussed with literature review. These papers may be useful and worthy of reference.

·         Liang E. Yang, et al, 2018. An agent-based modeling framework for simulating human exposure to environmental stresses in urban areas. Urban Science, 2018, 2(2):36. doi: 10.3390/urbansci2020036

·         L. E. Yang, et al, 2018. Assessment of Flood Losses with Household Responses: Agent-based Simulation in an Urban Catchment Area. Environmental Modelling and Assessment, https://doi.org/10.1007/s10666-018-9597-3

 

Section 3.1, line 92: Is “accumulation” a climate related disaster?

There needs reference for the model “UK Met Office, HadGEM2-ES” in section 3.2

Line 98, it should be RCP4.5 and RCP8.5

What are the observatory data (section 3.1) and climate model (section 3.2) used for? I don’t find any analysis or results from this data.

Please fill in Table 1 and table 2 with example values, rather than leaving them empty.

Line 177-191: contents here should move to an earlier place, for example, in section 2 and the beginning of section 3.3.

Section 4.1 including table 3 can be moved to section 2.  The contents in Section 4.1 are not “result” of the authors’ study but are just general information. And, there needs references when introducing the 4 major meteorological hazards.

Section 4.2, line 228-229, why does transportation in Nanjing have the highest exposure? Readers want to know why, but not just the statement. This applies also for other infrastructures, people want to know why the city has highest exposure level.

Section 4.2, the authors often say “the projected climate change in the 2050s”. But I didn’t find any climate projection in this paper. The authors must introduce what are the projected climate changes in the 2050s.

Transportation system in Hefei has lowest exposure but highest vulnerability, why? Water system in Shanghai has the highest exposure level but the lowest vulnerability level, why? Energy system in Shanghai also has the highest exposure level but the lowest vulnerability level, why?  Why theses cities have converse exposure and vulnerability?

Section 4.3 has the headline “climate risk assessment”, and the authors introduced risk as the function of severity and likelihood. But the section 4.3 has nothing about risk, severity or likelihood.

Author Response

Dear Reviewer 1

Please find attached the file for our response to your constructive comments. 

Best

Huan

Author Response File: Author Response.docx

Reviewer 2 Report

As Index-based climate risk assessment is Your added value I suggest to highlight this in the title.

Could You reconsider this fragment: The framework serves as an effective way to consolidate diverse opinions of various stakeholders on their assessments of sector-specific risks posed by climate change, and to aggregate these opinions into intuitive and comparable graphs. ? and write it more comprehensibly ?

Abstract suggests (as far as understood Your intentions) that You developed some aggregated risk index. The results are presented basing on the matrix concept? What is Your innovation?

Inappropriate style of citation. Follow the MDPI’s instructions for Authors please.

Provide explanations of the all acronyms, please.

Please enhance literature review. Update the sources. Could to provide some references, which examine interplaying problems of climate change (pluvial, thermal issues) with the newly urbanised and developed lands (urban sprawl)? You will find some cases in MDPI Water and Sustainably 2018. Discuss the relevant literature on newest tools and assessment frameworks.

Provide original references for all used or mentioned circulation models.

I’m confused… in one place You declare nameless Index-based climate risk assessment framework, in the other it‘s Climate and Infrastructure Assessment Tool (CIAT). I suppose it the same, anyway I strongly suggest to unify the nomenclature and use it consequently. Therefore consider to use CIAT name I the title and abstract...

Provide research workflow scheme please. Methodology is not clear. You mention about mapping (line 93) the meteorological conditions – how the maps are used on the next steps? Detail workflow chart could be fruitful.

Line 140: provide the criteria of expert selection, how did you evaluate “comprehensive (…) experience and (…) high awareness”. Avoid non-precise descriptions.

Line 112 – discus relevant literature;

Section 4.3 probably improper figure numbering. Please do not start the section with chart presentation. Good practise is to introduce the visualisation in the text body, at the first.

Section 5. Discussion need to be enhanced. Refer Your methodology to the others.

Author Response

Dear Reviewer 2

Thanks for your constructive comments for our paper. Please refer to our report for our responses. 

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

I appreciate that the authors responded to my former comments and revised the manuscript. However, still several key problems of the paper are not well addressed (see below the details).  Thus I suggest the authors to make another major revision.

The abstract is lack of research findings. It is necessary to show the most important research results in the abstract with 2-3 sentences.

Page 1, line 39. IPCC (2012) defined ….

The literature review is still very weak. What kind of index-based methods have been used in climate risk assessment? What’s the difference between your index method and the existing methods? The author only referred to two index-method papers and didn’t discuss that index-methods at all. This is far less sufficient. The authors could better compare several index-methods and point out the deficits of them, and thus propose own index-method.

·         Liang Yang, et al., 2015.   Climate-related Flood Risks and Urban Responses in the Pearl River Delta,      China. Regional Environmental Change. 15(2):379-391.

The authors didn’t address my former comment: There are already huge amount of papers assessing climate risk in cities and other, including heat wave, air pollution, floods, and typhoons. What are the typical serious climate risks and hazards in YRD? Why didn’t the authors mention any of such studies? For example:

·         Liang E. Yang, Peter Hoffmann, Jürgen Scheffran, 2017. Health impacts of smog pollution: the human dimensions of exposure. Lancet Planetary Health, 2017,1(4):e132-e133.

·         Analyzing explanatory factors of urban pluvial floods in Shanghai using geographically weighted regression. Stochastic Environmental Research and Risk Assessment. September 2017, Volume 31, Issue 7, pp 1777–1790

The paper studies climate risks in the YRD cities, but the authors cited only two papers on urban heat island in YRD.  Are there not any paper about floods, typhoon, drought, air pollution in YRD? Why those studies were not mentioned?

The line 63-71, there needs some references to evidence climate risks in the studied cities. It is very weak if the authors introduce these without any literature supports.

Line 71-79: this is the method and data collection, which can be moved to section 3.

Figure 1: please change miles to kilometer. And, please differentiate the 6 case cities and others in the map.

Figure 2, the texts are too small. Please use bigger text. Figure 3, 4, 5 also need bigger texts.

 

Section 3.1: what are the climate model and projection results? The authors said that the assessment outcomes of climate models and the projected climate change in the 2050s were presented at the beginning of each focus-group meetings and therefore served as the base for focus-group discussions. But still, readers also want to know the climate model outcomes and the climate projections. It is necessary to show them in the paper.

Table 3 confuses people. Please clarify what are the table head? Why many repeated contents in the table? Is this table a questionnaire to stakeholders, or is it the answered questionnaire? How did you use these qualitative information?

In section 5, the authors only talked about importance of the method, but there are not any contents about the research results. The authors should clearly conclude what are the findings/results of this study, and what are the climate risk and vulnerability in the YRD cities.

 

Line 80, there needs a “the” before “study area”.   

Line 177, please change “;” to “,”.   

Line 205, vulnerability please use small “v”.  

Line 282 “Now let’s compare the exposure…” this language is very unusual in scientific papers    …………..  

There are many such kind of small mistakes or in-appropriate usage of words in the text. The English language needs to be further improved, better by native English speaker.

Author Response

Dear Reviewer

Thanks for your constructive comments. Please see attached the point-to-point responses to your comments. We believe that we have carefully incorporated your advice in our revision and appreciate your feedback.

Author Response File: Author Response.pdf

Reviewer 2 Report

Thank You for all improvements. Although I think, that review could cover more articles, I’m satisfied.

Please study the labels of blocks in fig. 2 – there some flaws that need to be corrected.

Author Response

Dear Reviewer

Thanks for your positive feedback to our revision. Please see attached the response for the second round of our revision. 

Author Response File: Author Response.docx

Round 3

Reviewer 1 Report

Thanks for the authors efforts in revising the manuscript, which has been greatly improved.  

I suggest the paper be considered for publish after better editing and laying-out the Table 2 and 3.  There are too much information in table 3 which confuses readers. And, some more words are needed in the main text to introduce the tables.