scholarly journals Analysis of the characteristics of global virtual water trade network using degree and eigenvector centrality, with a focus on food and feed crops

2016 ◽  
Author(s):  
Sang-Hyun Lee ◽  
Rabi H. Mohtar ◽  
Jin-Yong Choi ◽  
Seung-Hwan Yoo

Abstract. This study aims to analyse the characteristics of global virtual water trade (GVWT) such as connectivity of each trader, vulnerable importers, and influential countries using degree and eigenvector centrality during the period 2006–2010. The degree centrality was used to measure the connectivity and eigenvector centrality was used to measure the influence on entire GVWT network. Mexico, Egypt, China, Korea Rep., and Japan were classified to vulnerable importers because they imported a lot of virtual water with the low connectivity. Especially, Egypt had 15.3 Gm³ year-1 blue water savings effects through GVWT, thus the vulnerable structure could cause the water shortage problem in importer. The entire GVWT network could be changed by a few nodes which call influential traders, and we figured out the influential traders using eigenvector centrality. In GVWT for food crops, the USA, Russian Federation, Thailand, and Canada had high eigenvector with a large volume of green water trade. In case of blue water trade, western Asia, Pakistan, and India had high eigenvector centrality. For feed crops, the green water trade in the USA, Brazil, and Argentina was the most influential. However, Argentina and Pakistan used the high proportion of internal water resource for virtual water export (32.9 and 25.1 %), thus rest of traders should consider the water resource management in these exporters carefully.

2016 ◽  
Vol 20 (10) ◽  
pp. 4223-4235 ◽  
Author(s):  
Sang-Hyun Lee ◽  
Rabi H. Mohtar ◽  
Jin-Yong Choi ◽  
Seung-Hwan Yoo

Abstract. This study aims to analyze the characteristics of global virtual water trade (GVWT), such as the connectivity of each trader, vulnerable importers, and influential countries, using degree and eigenvector centrality during the period 2006–2010. The degree centrality was used to measure the connectivity, and eigenvector centrality was used to measure the influence on the entire GVWT network. Mexico, Egypt, China, the Republic of Korea, and Japan were classified as vulnerable importers, because they imported large quantities of virtual water with low connectivity. In particular, Egypt had a 15.3 Gm3 year−1 blue water saving effect through GVWT: the vulnerable structure could cause a water shortage problem for the importer. The entire GVWT network could be changed by a few countries, termed "influential traders". We used eigenvector centrality to identify those influential traders. In GVWT for food crops, the USA, Russian Federation, Thailand, and Canada had high eigenvector centrality with large volumes of green water trade. In the case of blue water trade, western Asia, Pakistan, and India had high eigenvector centrality. For feed crops, the green water trade in the USA, Brazil, and Argentina was the most influential. However, Argentina and Pakistan used high proportions of internal water resources for virtual water export (32.9 and 25.1 %); thus other traders should carefully consider water resource management in these exporters.


2014 ◽  
Vol 06 (02) ◽  
pp. 141-148 ◽  
Author(s):  
F. Mohammadi-Kanigolzar ◽  
J. Daneshvar Ameri ◽  
N. Motee

2014 ◽  
Vol 18 (12) ◽  
pp. 5025-5040 ◽  
Author(s):  
B. J. Dermody ◽  
R. P. H. van Beek ◽  
E. Meeks ◽  
K. Klein Goldewijk ◽  
W. Scheidel ◽  
...  

Abstract. The Romans were perhaps the most impressive exponents of water resource management in preindustrial times with irrigation and virtual water trade facilitating unprecedented urbanization and socioeconomic stability for hundreds of years in a region of highly variable climate. To understand Roman water resource management in response to urbanization and climate variability, a Virtual Water Network of the Roman World was developed. Using this network we find that irrigation and virtual water trade increased Roman resilience to interannual climate variability. However, urbanization arising from virtual water trade likely pushed the Empire closer to the boundary of its water resources, led to an increase in import costs, and eroded its resilience to climate variability in the long term. In addition to improving our understanding of Roman water resource management, our cost–distance-based analysis illuminates how increases in import costs arising from climatic and population pressures are likely to be distributed in the future global virtual water network.


2011 ◽  
Vol 347-353 ◽  
pp. 2949-2956
Author(s):  
Ai Min Tian ◽  
Ning Dong ◽  
An Xi Jiang

water footprint and virtual water emerge as new concepts of international water resource studies in recent years and they also become prevailing topics in the study of international water resource at present. These concepts liberate the studies from the limitation of real water viewpoint and introduce the perspective of virtual water, which makes a vital contribution to the study of sustainable use of water resource. This paper introduces the internationally leading water resource footprint model and calculation method of virtual water into the water resource system of Jinan for the first time, giving a quantified measurement of the amount of virtual water contained in the main agricultural products and industrial products of Jinan. According to the calculation and analysis based on water footprint model of Jinan, it is concluded that Jinan is a net exporter of virtual water with an import dependence factor of 0, which directly endangers the water resource security of Jinan. Therefore, it is suggested to make adjustments on virtual water trade structures and strategies to upgrade industrial structures and increase the export volume of industrial products which contained less water, so as to use the water resource in a sustainable and effective way; with limited water resource, Jinan must seek innovations on water resource management concepts in addition to saving water and making better use of water resource, to alter consumption modes and implement the strategy of virtual water by introducing “outer source”, aiming to relieve water resource shortage through virtual water trade with no efforts spared.


2014 ◽  
Vol 11 (6) ◽  
pp. 6561-6597 ◽  
Author(s):  
B. J. Dermody ◽  
R. P. H. van Beek ◽  
E. Meeks ◽  
K. Klein Goldewijk ◽  
W. Scheidel ◽  
...  

Abstract. The Romans were perhaps the most impressive exponents of water resource management in preindustrial times with irrigation and virtual water trade facilitating unprecedented urbanisation and socioeconomic stability for hundreds of years in a region of highly variable climate. To understand Roman water resource management in response to urbanisation and climate variability, a Virtual Water Network of the Roman World was developed. Using this network we find that irrigation and virtual water trade increased Roman resilience to climate variability in the short term. However, urbanisation arising from virtual water trade likely pushed the Empire closer to the boundary of its water resources, led to an increase in import costs, and reduced its resilience to climate variability in the long-term. In addition to improving our understanding of Roman water resource management, our cost-distance based analysis illuminates how increases in import costs arising from climatic and population pressures are likely to be distributed in the future global virtual water network.


Water ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 671
Author(s):  
Xiaoying Zhou ◽  
Feier Wang ◽  
Kuan Huang ◽  
Huichun Zhang ◽  
Jie Yu ◽  
...  

Predicting and allocating water resources have become important tasks in water resource management. System dynamics and optimal planning models are widely applied to solve individual problems, but are seldom combined in studies. In this work, we developed a framework involving a system dynamics-multiple objective optimization (SD-MOO) model, which integrated the functions of simulation, policy control, and water allocation, and applied it to a case study of water management in Jiaxing, China to demonstrate the modeling. The predicted results of the case study showed that water shortage would not occur at a high-inflow level during 2018–2035 but would appear at mid- and low-inflow levels in 2025 and 2022, respectively. After we made dynamic adjustments to water use efficiency, economic growth, population growth, and water resource utilization, the predicted water shortage rates decreased by approximately 69–70% at the mid- and low-inflow levels in 2025 and 2035 compared to the scenarios without any adjustment strategies. Water allocation schemes obtained from the “prediction + dynamic regulation + optimization” framework were competitive in terms of social, economic and environmental benefits and flexibly satisfied the water demands. The case study demonstrated that the SD-MOO model framework could be an effective tool in achieving sustainable water resource management.


2021 ◽  
Author(s):  
Elena De Petrillo ◽  
Marta Tuninetti ◽  
Francesco Laio

<p>Through the international trade of agricultural goods, water resources that are physically used in the country of production are virtually transferred to the country of consumption. Food trade leads to a global redistribution of freshwater resources, thus shaping distant interdependencies among countries. Recent studies have shown how agricultural trade drives an outsourcing of environmental impacts pertaining to depletion and pollution of freshwater resources, and eutrophication of river bodies in distant producer countries. What is less clear is how the final consumer – being an individual, a company, or a community- impacts the water resources of producer countries at a subnational scale. Indeed, the variability of sub-national water footprint (WF in m<sup>3</sup>/tonne) due to climate, soil properties, irrigation practices, and fertilizer inputs is generally lost in trade analyses, as most trade data are only available at the country scale. The latest version of the Spatially Explicit Information on Production to Consumption Systems model  (SEI-PCS) by Trase provides detailed data on single trade flows (in tonne) along the crop supply chain: from local municipalities- to exporter companies- to importer companies – to the final consumer countries. These data allow us to capitalize on the high-resolution data of agricultural WF available in the literature, in order to quantify the sub-national virtual water flows behind food trade. As a first step, we assess the detailed soybean trade between Brazil and Italy. This assessment is relevant for water management because the global soybean flow reaching Italy may be traced back to 374 municipalities with heterogeneous agricultural practises and water use efficiency. Results show that the largest flow of virtual water from a Brazilian municipality to Italy -3.52e+07 m<sup>3</sup> (3% of the total export flow)- comes from Sorriso in the State of Mato Grosso. Conversely, the highest flow of blue water -1.56e+05 m<sup>3</sup>- comes from Jaguarão, in the State of Rio Grande do Sul, located in the Brazilian Pampa. Further, the analysis at the company scale reveals that as many as 37 exporting companies can be identified exchanging to Italy;  Bianchini S.A is the largest virtual water trader (1.88 e+08 m<sup>3</sup> of green water and 3,92 e+06 m<sup>3</sup> of blue water), followed by COFCO (1,06 e+08 m<sup>3</sup> of green water and 6.62 m<sup>3</sup> of blue water)  and Cargill ( 6.96 e+07 m<sup>3</sup> of green water and 2.80 e+02 m<sup>3</sup> of blue water). By building the bipartite network of importing companies and municipalities originating the fluxes we are able to efficiently disaggregate the supply chains , providing novel tools to build sustainable water management strategies.</p>


2014 ◽  
Vol 18 (6) ◽  
pp. 2103-2111 ◽  
Author(s):  
L. J. Zhang ◽  
X. A. Yin ◽  
Y. Zhi ◽  
Z. F. Yang

Abstract. China is a water-stressed country, and agriculture consumes the bulk of its water resources. Assessing the virtual water content (VWC) of crops is one important way to develop efficient water management measures to alleviate water resource conflicts among different sectors. In this research, the VWC of rice, a major crop in China, is taken as the research object. China covers a vast land area, and the VWC of rice varies widely between different regions. The VWC of rice in China is assessed and the spatial characteristics are also analysed. The total VWC is the total volume of freshwater both consumed and affected by pollution during the crop production process, including both direct and indirect water use. Prior calculation frameworks of the VWC of crops did not contain all of the virtual water content of crops. In addition to the calculation of green, blue and grey water – the direct water in VWC – the indirect water use of rice was also calculated, using an input–output model. The percentages of direct green, blue, grey and indirect water in the total VWC of rice in China were found to be 43.8, 28.2, 27.6, and 0.4%. The total VWC of rice generally showed a roughly three-tiered distribution, and decreased from southeast to northwest. The higher values of direct green water usage were mainly concentrated in Southeast and Southwest China, while the values were relatively low in Northwest China and Inner Mongolia. The higher direct blue water values were mainly concentrated in the eastern and southern coastal regions and Northwest China, and low values were mainly concentrated in Southwest China. Grey water values were relatively high in Shanxi and Guangxi provinces and low in Northeast and Northwest China. The regions with high values for indirect water were randomly distributed but the regions with low values were mainly concentrated in Northwest and Southwest China. For the regions with relatively high total VWC the high values of blue water made the largest contribution, although for the country as a whole the direct green water is the most important contributor.


2006 ◽  
Vol 10 (3) ◽  
pp. 455-468 ◽  
Author(s):  
A. K. Chapagain ◽  
A. Y. Hoekstra ◽  
H. H. G. Savenije

Abstract. Many nations save domestic water resources by importing water-intensive products and exporting commodities that are less water intensive. National water saving through the import of a product can imply saving water at a global level if the flow is from sites with high to sites with low water productivity. The paper analyses the consequences of international virtual water flows on the global and national water budgets. The assessment shows that the total amount of water that would have been required in the importing countries if all imported agricultural products would have been produced domestically is 1605 Gm3/yr. These products are however being produced with only 1253 Gm3/yr in the exporting countries, saving global water resources by 352 Gm3/yr. This saving is 28 per cent of the international virtual water flows related to the trade of agricultural products and 6 per cent of the global water use in agriculture. National policy makers are however not interested in global water savings but in the status of national water resources. Egypt imports wheat and in doing so saves 3.6 Gm3/yr of its national water resources. Water use for producing export commodities can be beneficial, as for instance in Cote d'Ivoire, Ghana and Brazil, where the use of green water resources (mainly through rain-fed agriculture) for the production of stimulant crops for export has a positive economic impact on the national economy. However, export of 28 Gm3/yr of national water from Thailand related to rice export is at the cost of additional pressure on its blue water resources. Importing a product which has a relatively high ratio of green to blue virtual water content saves global blue water resources that generally have a higher opportunity cost than green water.


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