Research on the Measurement and Influencing Factors of Implicit Water Resources in Import and Export Trade from the Perspective of Global Value Chains
Round 1
Reviewer 1 Report
The manuscript analysed the Virtual Water Trade in China by data from the World Input-Output Database and identified the influencing factors of change by the SDA decomposition. Data of three years (2007-2010-214) were considered.
General comments:
After carefully reading the manuscript, I suggest a major review before its publication on this journal.
In the abstract and in the conclusions the novelty of the work should be highlighted to discriminate which are its real contributions and which are re-elaborations of well-known concepts.
I would suggest improving the presentation of the paper. In this version paragraphs 3.2.1 and 3.2.2 are very similar and repetitive and contain lots of numbers, which makes it hard for the reader to follow the description of results.
It is not clear to me how the authors set the years 2007, 2010 and 2014, this choice should be justified.
The authors should check the use of punctuation marks and capital letters (lines 71, 120, 232, 236, 256, 315, 318).
Specific comments:
line 192: "virtual water" is to be erased
Figures: Please, add the titles of the axes in the graphs
lines 280-283: Please, check this sentence as in the first stage the department 1 have an impact larger than the department 4 (Figure 2)
line 374: I think it should be "import industry sructure"
line 378: I think it should be "positive effect" and not "negative effects"
line 381: there is a missing negative value
Figure 5: the graph is trimmed (see value of department 17)
line 445: Please, define R&D technology
Author Response
Response to Reviewer Comments
Thank you for spending valuable time providing quite useful comments on our work (manuscript number: Water-1174222). It is amazing that you have devoted so much time on our paper and your comments really help us to further improve it. We have carefully revised the manuscript according to reviewer’s comments, and the revised portion is clearly highlighted. Our responses to several comments are listed below:
Point 1:In the abstract and in the conclusions the novelty of the work should be highlighted to discriminate which are its real contributions and which are re-elaborations of well-known concepts.
Response: Thank you for your valuable suggestions. This article specifically explains the innovation and contribution of the article in the abstract and conclusion. For details, please refer to the original abstract and conclusion.
Point 2: I would suggest improving the presentation of the paper. In this version paragraphs 3.2.1 and 3.2.2 are very similar and repetitive and contain lots of numbers, which makes it hard for the reader to follow the description of results.
Response: Thank you for your valuable suggestions. We have carefully revised the article, and made significant changes to 3.2.1 and 3.2.2. The specifics have been displayed in the revision pattern in the main text.
Point 3: It is not clear to me how the authors set the years 2007, 2010 and 2014, this choice should be justified.
Response: Due to space limitations, we will select the years before and after the 2008 global financial crisis and the latest 2014 data results for analysis. Because before and after the financial crisis, it can clearly reflect the changing characteristics of world trade, and it can reflect the true situation of trade hidden water resources from the perspective of global value chain trade.
Point 4: The authors should check the use of punctuation marks and capital letters (lines 71, 120, 232, 236, 256, 315, 318).
Response: Thank you for your valuable suggestions.We had already checked the use of punctuation marks and capital letters,please see lines 65,114,244. The lines were changed, because the content of the article is modified or deleted.
Point 5: Specific comments:
(1)line 192: "virtual water" is to be erased
Response:"virtual water" has been deleted in new line186.
(2)Figures: Please, add the titles of the axes in the graphs
Response:Thank you for your valuable suggestions.However, in the paper writing specification, when there is a title under the graph, there is no need to add the titles of the axes in the graphs in the graph, otherwise it will affect the appearance of the graph. If it is very necessary, we will modify, Thank you so much.
(3)lines 280-283: Please, check this sentence as in the first stage the department 1 have an impact larger than the department 4 (Figure 2)
Response:Thank you for your valuable suggestions.We had modified it, please see new line 268-271.
(4)line 374: I think it should be "import industry sructure"
Response:This part of the structure of the import industry will be covered later. Please see line 380.
(5)line 378: I think it should be "positive effect" and not "negative effects"
Response:Thank you for your valuable suggestions.We had modified in line 323.
(6)line 381: there is a missing negative value
Response:Because the sentence has been deleted, I am sorry you can’t see the changes.
(7)Figure 5: the graph is trimmed (see value of department 17)
Response:We had made changes in Figure 5.
(8)line 445: Please, define R&D technology
Response:The define of R&D technology is:Technologies for improving efficiency and resource utilization in the production process of products
At last: Thank the referee for providing all these detailed errors and we have gone through them and revised them in the manuscript. If there is still a lack of modify, we will continue to make positive corrections.
Reviewer 2 Report
Please consider the suggestions that are included in the attached pdf file
Particularly
State some evidence about China's trade growth and water needs (line 45)
Use the term "virtual water trade" throughout the text (line 66)
Clearly state A*gd (domestic intermediate input structure effect) differences (lines 160-162)
Comments for author File: 
Comments.pdf
Author Response
Response to Reviewer Comments
Thank you for spending valuable time providing quite useful comments on our work (manuscript number: Water-1174222). It is amazing that you have devoted so much time on our paper and your comments really help us to further improve it. We have carefully revised the manuscript according to reviewer’s comments, and the revised portion is clearly highlighted. Our responses to several comments are listed below:
Point 1:Please provide some data or references that underpin this statement.
See for example OECD stats.
Response:Thank you for your valuable suggestions,for the sentences you mentioned, we had quoted the corresponding references to support.
Point 2: The term "virtual water trade" is more accurate and understandable. Please correct throughout the study.
Response: Thank you for your valuable suggestions,We have adopted "virtual water trade" and replaced it in the full text.
Point 3: Clearly state A*gd (domestic intermediate input structure effect) differences (lines 160-162),What is the difference between the two highlighted parts?
Response: Agd is domestic intermediate input-output structure effect,and A-gd is other domestic intermediate input-output structure effect.We had modified the article on lines 158-160, thank you for your reminder.
At last: Thank the referee for providing all these detailed errors and we have gone through them and revised them in the manuscript. If there is still a lack of modify, we will continue to make positive corrections.
Author Response File: 
Author Response.doc
Reviewer 3 Report
The paper adopts a value-added decomposition of trade on multi-region (global) input-output tables. The value is in providing trends overtime of "virtual water" in production, consumption and trade across countries while discussing possible drivers of the same trends.
I have five main concerns about this paper:
A) At this stage, it is very difficult to read and follow the arguments. Starting from the (too long!) abstract, the authors need to be more concise. Just as an example, when reporting results, leave the smaller details about descriptive statistics later in the text while leaving upfront the novelty of the method and the general trends.
B) The novelty of the paper lies in the application of a decomposition à la Koopman et al to the specific field of "virtual water". I find the idea intriguing. Yet the authors need to specify better if and how their analysis differentiates from other similar and more general studies for all goods and services, while possibly recalling better the related literature on Global Value Chains. If I did not know before how such decompositions were used, I would not have understood the value of the paper.
C) More recently world input-output tables have been used also to catch "input centrality" on a global scale. See for example Rungi, Fattorini and Huremovic (2020) on 'Measuring the Input Rank in Global Supply Networks'. Centrality, as a network dimension, is demonstrated to be complementary to position dimensions, like the ones that authors propose. I am sure it would be interesting for the readers to catch the (direct and indirect) relevance of "virtual water" also after considering the complexity of the international supply structures.
D) Personally, I do not understand the role of Shapley values in the analyses. Please explain better the pros and cons of using them. The text does not provide a proper justification for implementing them on computations from input-output tables.
E) Finally, conclusions should better frame the utility of findings from a policy perspective. To simplify, observed trends apparently show that there has been some efficacy of saving policy. For example, can the authors at least speculate in conclusion that, given actual policies, we could foresee a further decrease in virtual water usage? Did we touch the bottom of the trend?
Author Response
Response to Reviewer Comments
Thank you for spending valuable time providing quite useful comments on our work (manuscript number: Water-1174222). It is amazing that you have devoted so much time on our paper and your comments really help us to further improve it. We have carefully revised the manuscript according to reviewer’s comments, and the revised portion is clearly highlighted. Our responses to several comments are listed below:
Point 1: At this stage, it is very difficult to read and follow the arguments. Starting from the (too long!) abstract, the authors need to be more concise. Just as an example, when reporting results, leave the smaller details about descriptive statistics later in the text while leaving upfront the novelty of the method and the general trends.
Response:Thank you for your valuable suggestions. This article has made some efforts in concise aspects such as abstracts. Please refer to the original text for details. This is the new Abstract:
Based on Multi-Region Input-Output tables, China's Virtual Water Trade were Measured, and its Influencing Factors of Change were decomposed. The results reveal that: Virtual Water exports and Imports Increased from 161.5 Billion Tons and 114.07 Billion Tons in 2007 to 193.31 Billion Tons and 157.1 Billion Tons in 2014. Eight economies account for more than 50% of China's total virtual water exports and imports, the total of the United States, Japan and Europe Even reached 44% (exports) and 31.3% (imports). Export scale, export of intermediate products, export industry structure, domestic water consumption coefficient and domestic intermediate input structure are the main factors of the change of virtual water export. The growth of export scale is the primary reason for the growth of virtual water export，The decline of domestic water consumption coefficient is the primary reason for restraining the growth of virtual water export. Import scale, import of intermediate products, import industry structure, water consumption coefficient of foreign countries and the correlation between domestic industries are the main factors affecting the change of virtual water import. The growth of import scale is the primary reason for the growth of virtual water import in most sectors, The decline of water consumption coefficient abroad is the primary reason for restraining the growth of virtual water import.
Point 2: The novelty of the paper lies in the application of a decomposition à la Koopman et al to the specific field of "virtual water". I find the idea intriguing. Yet the authors need to specify better if and how their analysis differentiates from other similar and more general studies for all goods and services, while possibly recalling better the related literature on Global Value Chains. If I did not know before how such decompositions were used, I would not have understood the value of the paper.
Response: Thank you for your valuable suggestions. The research of Koopman and Wang and others have indeed inspired many scholars. Since then, many scholars have combined this decomposition method to make the basis for related fields, but it is more in the field of macroeconomics and sectoral economics,the research in the field of virtual water has not been in-depth yet, this research will do some efforts to expand in this field. (Please see line 59 of the article for details )
Point 3: More recently world input-output tables have been used also to catch "input centrality" on a global scale. See for example Rungi, Fattorini and Huremovic (2020) on 'Measuring the Input Rank in Global Supply Networks'. Centrality, as a network dimension, is demonstrated to be complementary to position dimensions, like the ones that authors propose. I am sure it would be interesting for the readers to catch the (direct and indirect) relevance of "virtual water" also after considering the complexity of the international supply structures.
Response: Thank you for your valuable suggestions. The exploration of "input centrality" in the use of input-output tables in this article is indeed inspiring to this article. It has been cited and identified in the article.
Rungi A , Fattorini L , Huremovic K . Measuring the Input Rank in Global Supply Networks[J]. Social Science Electronic Publishing, 2020.
Point 4: Personally, I do not understand the role of Shapley values in the analyses. Please explain better the pros and cons of using them. The text does not provide a proper justification for implementing them on computations from input-output tables.
Response: The shapley method used in this research is mainly to solve the problem of residual items in the decomposition process. Thank you for your suggestion.
Point 5: Finally, conclusions should better frame the utility of findings from a policy perspective. To simplify, observed trends apparently show that there has been some efficacy of saving policy. For example, can the authors at least speculate in conclusion that, given actual policies, we could foresee a further decrease in virtual water usage? Did we touch the bottom of the trend?
Response: Thank you for your valuable suggestions. This article has made additions and modifications in the corresponding sections.As follows:
In this study, the value-added decomposition analysis method is applied to the study of virtual water.Trade scale as the primary factor affecting the virtual water trade volume, can reduce the consumption of resources by optimizing the export structure, although its scale is difficult to control. The SDA decomposition results of this paper also show that the import and export industry structure has an important impact on the virtual water trade volume. As an important factor to restrain the growth of virtual water, the reduction of water consumption coefficient has achieved remarkable results in recent years, and will remain a feasible and important scheme in the future. The trade proportion of intermediate products and the forward and backward correlation with other countries all have an important impact on the virtual water trade volume. Therefore, actively participating in the division of labor in the global value chain, enhancing the level of R&D technology and promoting its position in the global value chain are not only of great significance in terms of economic effects, but also very urgent in terms of resource conservation and utilization. In addition, the domestic intermediate input-output structure is also a factor that needs attention, so it is very important to improve the efficiency of intermediate input and optimize the structure of intermediate input products.It is foreseeable that with the growth of economic and trade scale, virtual water consumption will still increase, but advances in technology and structure will ease this growth to a greater extent. In the new era, as a responsible big country, the breadth and depth of participating in international division of labor and international trade are bound to expand constantly, and it is increasingly important to develop an open economy with high quality. The data and related policy suggestions obtained in this paper deserve attention.(see line 443-465 for details)
At last: Thank the referee for providing all these detailed errors and we have gone through them and revised them in the manuscript. If there is still a lack of modify, we will continue to make positive corrections.
Round 2
Reviewer 1 Report
I carefully read the author's answers and the new version of the manuscript.
The authors made changes in the text improving the language and style, but English still needs to be improved for the publication of the manuscript.
Furthermore, there are some punctuation errors throughout the manuscript that need to be corrected (e.g. lines 283, 328, 384, 441).
Comments:
Please, check the sentences at lines 252 ("industrial linkages among other countries") and 388 ("other domestic industries are related");
Figure 1: Please, avoid overlapping text;
Figures 2-5: in my opinion the caption of the figure does not describe the quantities that are represented on the x and y axes;
line 467: there is still a missing value after sign minus
Author Response
Thank you for spending valuable time providing quite useful comments on our work. Your comments have helped us to further improve the manuscript. We have carefully revised the manuscript according to reviewer’s suggestions. Please find our revisions as follows:
Point 1:I carefully read the author's answers and the new version of the manuscript.
The authors made changes in the text improving the language and style, but English still needs to be improved for the publication of the manuscript.
Response: Thank you for your valuable suggestions.We will continue to modify the language issues of the article during the proofreading process.
Point 2:There are some punctuation errors throughout the manuscript that need to be corrected (e.g. lines 283, 328, 384, 441).
Response: Thank you for your valuable suggestions. We have corrected the punctuation errors on lines 283, 328, 384, and 441.
Point 3: Please, check the sentences at lines 252 ("industrial linkages among other countries") and 388 ("other domestic industries are related").
Response: Thank you for your valuable suggestions. We have checked the sentences at lines 252 ("industrial linkages among other countries") and 388 ("other domestic industries are related"), modified "industrial linkages among other countries" as "industrial linkages among the other countries" in the main text.
Point 4: Figure 1: Please, avoid overlapping text.
Response: We have modified the overlapping text in Figure 1. You can view the PDF document.
Point 5: Figures 2-5: in my opinion the caption of the figure does not describe the quantities that are represented on the x and y axes.
Response: Thank you for your valuable suggestions.We have described in content of the article, if describe quantities in the caption, the caption will be very long.
Point 6: line 467: there is still a missing value after sign minus
Response: Sorry, line467 is a reference, we did not find the missing value after sign minus.
At last: Thank the referee for providing all these detailed errors and we have gone through them and revised them in the manuscript. If there is still a lack of modify, we will continue to make positive corrections.
Author Response File: Author Response.pdf
Reviewer 3 Report
I appreciate the efforts of improving after my comments and suggestions. In my opinion, the contribution is well in the scope of the journal, and it can be published right after good English proofreading. I still find some grammar mistakes and sentences that are difficult to read.
Author Response
Thank you for spending valuable time providing quite useful comments on our work. Your comments have helped us to further improve the manuscript. We have carefully revised the manuscript according to reviewer’s suggestions. Please find our revisions as follows:
Point 1: I appreciate the efforts of improving after my comments and suggestions. In my opinion, the contribution is well in the scope of the journal, and it can be published right after good English proofreading. I still find some grammar mistakes and sentences that are difficult to read.
Response: Thank you for your valuable suggestions.We will continue to modify the language issues of the article during the proofreading process.
At last: Thank the referee for providing all these detailed errors and we have gone through them and revised them in the manuscript. If there is still a lack of modify, we will continue to make positive corrections.
Author Response File: Author Response.pdf
