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Purpose: Low water resource utilization rate, water environment pollution, and water ecology deterioration are unfavorable factors restricting the high-quality development of the Yellow River basin and the coordinated development of the region, and industrial linkage is an important mechanism to promote the regional "pole-diffusion" effect. Currently, the water resource constraints of the Yellow River basin are close to the upper limit; in this context, how to enhance the industrial linkage between regions, promote the coordinated development of resources and economy in the Yellow River basin, and construct new "growth poles" of high-quality development has become an important proposition. Methods: By analyzing the mechanism of water resource constraints affecting industrial linkage and constructing a mediation effect model, we investigate the transmission mechanism of water resource constraints affecting industrial linkage through virtual water trade and optimization of industrial structure. Results: The results show that water resource constraints significantly inhibit the development of industrial linkage in the whole basin, but enhance the development of industrial linkage through the promotion of virtual water trade and optimization of industrial structure; in terms of subregions, there are differences in the mediation effect in the Yellow River basin in the regions with advantages in agriculture and animal husbandry, in the regions with advantages in the energy industry, and in the regions with advantages in the emerging industry and advanced manufacturing industry. Inspiration: This study has several aims: first, the rational use of the virtual water trade model of the Yellow River basin; second, use of the basin as a whole to promote the upgrading of industrial structure; third, the development of water resource rigid constraints in accordance with local conditions to promote the sustainable development of the economy; and fourth, promotion of the construction of the industrial community of the whole basin to realize the synergistic high-quality development of the Yellow River basin. Marginal contribution: In the study of high-quality development in the Yellow River basin, the existing literature focuses on the optimization of the industrial layout and industrial structure based on the theory of resource advantage and industrial division of labor. Based on this, this article analyzes the impact of water resource constraints on the industrial linkage of regions with advantages in agriculture and animal husbandry, energy industry, and emerging industry and advanced manufacturing industry from the perspective of the adaptability of water resources to the layout of productive forces and puts forward the proposal of coordinating the linkage development of industries in the whole river basin, which promotes the research on the relationship between water resources and industries. [ABSTRACT FROM AUTHOR]

Cotton, the world's most widely cultivated fiber crop, is associated with a multitude of environmental impacts, particularly the intensive use of water resources. While previous studies have assessed cotton's water usage through the water footprint concept, they largely focused on spatial variability, leaving temporal dynamics and the issue of unsustainable water use underexplored. This global study addressed these gaps by examining both the spatial and temporal variability of cotton's water footprint and assessing the unsustainable water footprint over time. Additionally, it explored the potential of flax as a water-efficient alternative for fiber production. Using a global gridded crop model, the study simulated yield and water use of flax and cotton from 1972 to 2018 at 30 arcmin resolution. The results showed that the global average blue, green, and total water footprint of cotton decreased by 37%, 48%, and 43%, respectively, due to yield improvements driven by improved crop cultivars, fertilizers, and better water management practices, with climate playing a minor role in these reductions. Despite this, the total water footprint of cotton production increased by 5%, with the blue water footprint rising by 17%. Additionally, unsustainable blue water usage in cotton cultivation increased from 59.3 km³/y to 70.9 km³/y between 1972-1976 and 2014–2018, with 71.1% of the unsustainable water traded virtually. USA, Pakistan, and India accounted for over 60% of this unsustainable virtual water trade. Flax, with its substantially lower water footprint, emerged as a promising alternative to reduce water consumption in fiber production. These findings offer critical insights for formulating strategies to mitigate unsustainable water use in global fiber production.

Argentina stands as the leading producer and exporter of olive products in the Americas, with the province of La Rioja as its main productive area. Since the 1990s, the olive grove cultivated area and related agro-industry in La Rioja have expanded. However, the resulting wastewater has generally been neglected. The water footprint (WF) provides information about the water volume consumed and polluted by a production process. Since the 1990s, agricultural and agro-industrial activities in La Rioja have experienced substantial growth. This study aims to analyze the generation, quality, and management of Oil Mill Wastewater (OMWW) using the grey WF of chloride and nitrate as an indicator and focusing on two olive mills (OM) in La Rioja. Additionally, it seeks to examine the relationship between the international trade of provincial olive oil and the estimated grey WF. For the diagnosis of OMWW generation, a description of the production process was made coupled with flow and physico-chemical characterization. The total grey WF was 8.69 and 45.5 L water/L olive oil for OM 1 and OM 2, respectively. Nitrate was identified as the critical pollutant. The grey virtual water export related to the export of olive oil was 5569 m3 for OM 1 and 28,000 m3 for OM 2. The provincial grey virtual water export related to olive oil was 161,955 m3 with major trade destinations including Spain, the United States, and Brazil. The article analyses for the first time the grey WF of olive oil industries and assess the related grey virtual water exports. This research represents a step forward in the knowledge of wastewater management in the olive oil sector and facilitates the search for solutions to minimize negative environmental impacts while promoting cleaner production. [ABSTRACT FROM AUTHOR]

China faces severe water resource shortages due to the uneven distribution of water resources and ever-increasing water demand driven by rapid industrialization and urbanization. The virtual water trade (VWT) is a potential solution to conserve water resources by transferring water from water-abundant/water-productive regions to water-scarce/less water-productive regions. Based on the inter-provincial input-output model, the provincial VWT of China was estimated at the sectoral level. The relationship of VWT with water resources in 30 provinces was analyzed in relation to the water stress index (WSI). It was found that (1) total inter-provincial VW trade showed a downward trend during the study period, with 363.91 km3 in 2002, 283.72 km3 in 2007, and 285.23 km3 in 2012. Overall, the primary industry dominated the VWT for most provinces. (2) China's virtual water flowed from the relatively underdeveloped central and western regions to the east with a relatively developed economy from the inter-provincial level. This trend became increasingly prominent. (3) In many instances, VW was transferred from water-poor to water-rich areas. These results imply that China needs to improve its water use efficiency and optimize its regional industrial structure. Additionally, establishing an ecological compensation mechanism is considered a valuable measure for China to alleviate regional water resource pressure. [ABSTRACT FROM AUTHOR]

Qatar is a severely water-stressed country. Despite Qatar's aridity and its lack of freshwater resources, its per capita water consumption is one of the highest in the world, and it is expected to increase in the coming decades. Therefore, understanding water consumption and use through space and time becomes paramount. By employing water footprint assessment (WF) and analysis of virtual water trade (VWT), this research comprehensively examines Qatar's water consumption patterns both domestically and internationally on a sectorial level (agricultural, industrial and urban sectors) between 2010 and 2021. The findings show that, internally, the urban sector contributed the most to the WF, followed by the industrial and the agricultural sectors with an annual average WF of 3250, 1650, and 50 million m3/y, respectively. Although Qatar exports large amounts of VW (1450 million m3/y), its VW imports (7530 million m3/y) are very high, reflecting the country's agricultural demand, making Qatar a net VW importing country. Qatar exhibits a national WF of consumption of 11,900 million m3/y, with a water dependency index of 56% and a self-sufficiency index of 44%. Additionally, Qatar has a significant water export fraction of 20%, while only 3% of its water consumption relies on its natural resources. This study pinpoints sectors and areas where WFs can be reduced; the outcomes serve as a foundation for strategic planning, enabling Qatar to make informed decisions to optimize its water resources, enhance water use efficiency, and secure a sustainable water future in the face of escalating water stress. This study's methodology and findings not only pave the way for more efficient water resource management in Qatar, but also offer a replicable framework for other arid and semi-arid countries to assess and optimize their water footprint and virtual water trade, contributing significantly to global efforts in sustainable water use. [ABSTRACT FROM AUTHOR]

In order to quantify trade-associated virtual water flows and evaluate their impact on regional water systems, this paper used the multi-region input-output model to reveal the pattern and structure of the virtual water trade inside and outsided of the Yellow River Basin in 2012,2015 and 2017 and used LMDI method to analyze the impact of the virtual water net output of the watershed relative to others, and used the QAP model to analyze the impact factors of the virtual water trade among provinces within the watershed. The results show that a) the Yellow River Basin as a whole presents a virtual water net input state, but the Yellow River Basin net exports virtual water to Beijing, Tianjin, Hebei and other 12 regions. b) The virtual water trade export industry is mainly the production and supply of agriculture, electricity, gas and water. c) Structure effect and intensity effect are important driving factors of virtual water net output in the watershed. d) QAP regression outcomes prove that economic development level, geographic distance and water use intensity differences are the main factors affecting the virtual water trade. [ABSTRACT FROM AUTHOR]

Water scarcity has received global attention in the last decade as it challenges food security in arid and semi-arid regions. This study employs water scarcity indices to assess water resources in the agricultural sector of Iran's Jazmourian watershed. Overall, we find that the watershed is experiencing a “very high stress” water situation. This is primarily due to intensive water usage for diverse crops, which has resulted in a negative net virtual water balance and contributed to a rise in water stress and poverty levels. The water stress index is 0.88, and the agricultural water stress is 1.25. The agricultural water footprint is 2,018.53 million cubic meters (MCM), with the share of blue, green and gray water footprints being 80.21, 6.08, and 13.72%, respectively. The region possesses 3,210 MCM of available water for crops, with 17.1% sourced from green waters and 82.9% from blue waters. Despite low annual rainfall and limited water resources, the region excessively exploits water for diverse crops. The net virtual water balance is negative, indicating high virtual water export (1,112–1,605 MCM) compared to imports (58–265 MCM). With declining water availability and increasing crop production, the region experiences rising water stress. The spatial analysis of sub-watersheds reveals diverse patterns of water stress and poverty, as detailed in the study. HIGHLIGHTS Water scarcity indices were quantified using water resource availability and the water footprint in the watershed scale.; The agricultural Water Stress Index was estimated based on agricultural water footprint and agricultural water resources.; The AWSI and blue water scarcity increased from 2008 to 2019 in the agricultural production of the Jazmurian watershed.;

This study delves into the intricate dynamics of South Korea's grain production and trade, specifically scrutinizing water resource management and sustainability trends from 1991 to 2022. The primary objective was to assess the temporal evolution of South Korea's agricultural virtual water trade in maize, soybeans and wheat. Employing the virtual water flows assessment method, water stress index, and an unsustainable import fraction (UIF) analysis, this research aimed to uncover key patterns and dynamics within the agricultural grain trade landscape. Utilizing comprehensive datasets encompassing grain trade, as well as water and land footprint data, this study assessed the intricate interplay between agricultural production, trade, and resource utilization. Results showed a reduction in local production for soybeans and a slight increase in domestic wheat production over the study period. In addition, the study revealed an overall increase in the virtual water imports associated with grain crops, with maize exhibiting the steepest upward trend in comparison with the other grains (wheat and soybeans). Furthermore, the study demonstrated that the import of maize contributed the highest amount of water and land savings, implying that this grain crop had the most significant impact on conserving local water and land resources. Environmental impact assessments, including water stress indices and the unsustainable import fractions, contributed to a comprehensive understanding of grain trade sustainability with concrete result values and insights, highlighting the intricate interplay of international grain trade and local water resource conservation in South Korea. By scrutinizing the virtual land and water dimensions of grain trade, this research offers valuable insights for policymakers and researchers striving to navigate the nexus of agriculture, trade, and resource management. The findings hold significance in the context of ensuring food security, optimizing resource allocation, and fostering sustainable agricultural practices in a dynamically evolving global landscape. [ABSTRACT FROM AUTHOR]

Water cycle is important for maintaining the dynamic balance of regional water resources. Here, based on the input–output water circulation flux accounting model, we take Xinjiang as a case area to empirically explore the mechanism of the 'nature‐society‐trade' ternary water cycle. The results show that the water transferred out was much larger than the transferred in in Xinjiang. The scale of water resources development and utilization and the social water cycle fluxes have been constantly expanding, but there was a mismatch between the hydrological system and the socio‐economic system in terms of water resource utilization. From 2007 to 2017, agriculture had always been the department with the largest amount of direct water consumption and virtual water transfer in Xinjiang, which mainly transferred virtual water to the light industry and service sector where the production of final products requires large amounts of agricultural products as raw materials or intermediate products. In Xinjiang, the virtual water transferred outside through trade in products and services was much larger than the virtual water transferred in from other regions, and it was thus always in a state of net virtual water outflow as a whole. In inter‐provincial trade of China, Xinjiang mainly transferred virtual water to areas with abundant water resources, developed economies and dense populations in eastern China. Lastly, we put forward targeted suggestions on the optimal allocation of water resources to promote the sustainable development of Xinjiang and we hope that our study will be instructive for water resources management in other arid inland river basins. [ABSTRACT FROM AUTHOR]

Due to international agriculture crops trade, significant virtual water flows are transferred between nations, known as virtual water trade. Virtual water trade affects the sustainability of freshwater resources worldwide. However, there is presently no sustainable virtual water usage classification that might serve as the basis for global virtual water management. This study's primary objective is to address this research gap. This work attempts to develop a novel virtual water trade classification to achieve freshwater resources' global sustainability. To classify VWT, the research presents a global analysis of the global trade of wheat virtual water. Our findings show that the global trade of wheat annually translocated an average of 268.5 billion m3 of virtual water among the nations, of which 89.33% was green water, 2.65% was blue water, and 8.02% was gray water. A classification of global virtual water trade based on this work is divided into three sustainability states: "strong sustainability," "balanced sustainability," and "fragile sustainability," as well as four unsustainable states, including "critical unsustainability," "high unsustainability," "moderate unsustainability" and "low unsustainability." [ABSTRACT FROM AUTHOR]

As key water suppliers and natural channels, large rivers have prospered production and trade. However, the emerging trade brought virtual water flows, which will change the physical water distribution. Accordingly, previous policies for water resources management at different scales should be adjusted to take this into account. Taking the Yangtze River Economic Belt (YREB) as a case study, a multi-scale analysis framework is here constructed to analyze the internal, domestic inter-regional and cross-border virtual water flow patterns. That is the base for the following policy design discussions. The World's and Chinese Muti-regional Input-output tables are nested and drivers for regional differences in virtual water flows are further disentangled by Structural decomposition analysis (SDA). Results show that current virtual water flows in the large-river economic belts worsen water distribution inequality if no management controls are implemented. Within the basin, net virtual water flows from the water-deficient reaches to upstream regions with abundant water. At an inter-regional scale, the YREB absorbs a net import of 8.44 × 109 m3 from the north with water shortage, but supplies about 6.7 × 108 m3 to the south. From a cross-border perspective, water stress in the YREB is strengthened by developed countries and alleviated by new emerging countries. Industrial structure effect and scale effect decide the direction of virtual water flows at a national scale, while regional structural effect counts more at a global scale. The water embodied in trades matters when carrying out water rights allocation, water transfer projects and water border adjustment mechanisms. [ABSTRACT FROM AUTHOR]

Cross-regional water allocation within the river basin, coupled with the development of specialized industries based on comparative advantages, can effectively mediate overall water use efficiency. The uneven distribution of water resources and structural contradictions in water usage hinder the sustainable development of water resources in the Yangtze River Economic Belt (YEB). This study aims to address these issues from the perspective of virtual water trade, to facilitate cross-regional water resource allocation and guide structural adjustments in industrial water use, ensuring water security. In this study, we developed a dynamic multi-regional input–output model (MRIO) to explore dynamic change of virtual water trade pattern in the YEB that evolves over time. This model sheds light on evolving virtual water transfer patterns and the nuances of water resource pressure transmission. Additionally, it quantifies sectoral water use variations, pinpointing the cornerstone industries across different regions. The findings are as follows: (1) The pattern of virtual water transfer predominantly towards the developed downstream regions remains unchanged, but regional disparities are gradually diminishing. (2) The upstream regions of the YEB transfer more water resource pressures externally, while the downstream regions do not experience excessive external transfers of water resource pressures. (3) The pattern of Agriculture-driven virtual water transfers is gradually being disrupted. While the upstream regions continue to rely on Agriculture as their pillar industries, the downstream regions are progressively shifting towards tertiary industries such as Service. These results indicate that economic development is the primary driver of changes in the the pattern of virtual water transfer, and economic disparities are a key factor in shaping the latest virtual water transfer. Based on existing policies, there is a need for comprehensive coordination of water resource allocation and strengthening of virtual water trade exchanges between regions to address the uneven distribution of water resources. Additionally, it is necessary to resolve structural water use conflicts by developing specialized economic strengths based on the main industries for virtual water in each region.

China's Yellow River, the nation's second-longest, grapples with severe water scarcity, impeding the high-quality development of its basin. Our study meticulously examines the intricate virtual water trade network inside and outside the basin, providing essential insights to combat its acute water scarcity. We calculated water consumption coefficients for seven pivotal sectors across diverse Chinese provinces, forming the foundational data for quantifying virtual water trade both inside and outside the basin. Utilizing the 2015 Multi-Regional Input-Output Table, we assessed the Yellow River Basin's reliance on external water resources. Despite enduring chronic water scarcity, the basin annually exports a substantial 27.2 billion m3 of virtual water, equivalent to half of its yearly runoff. This outflow predominantly flows to the economically advanced eastern coastal region, with Agriculture and Manufacturing sectors dominating. Significantly, an irrational industrial layout leads to a substantial transfer of virtual water from economically disadvantaged areas to more affluent regions, exacerbating water scarcity in the basin's less privileged areas. Our study yields critical insights for mitigating water shortages in the Yellow River Basin and provides a transferrable framework for regions worldwide grappling with analogous challenges. [ABSTRACT FROM AUTHOR]

Xinjiang had been suffering from acute water scarcity, which is an important constraint factor for its economic sustainability. Virtual water plays an important role in its sustainable development, and this paper tries to re-investigate the role of virtual water trade among the generalized trade framework in its sustainable development. The term generalized trade encompasses both physical and virtual trade. Physical trade refers to the transfer of commodities in monetary or barter form, and virtual trade refers to the transfer of inputs embodied in physical form (e.g., virtual water, energy, or land). It was in the water-scarce status, but it transported a net volume of about 13.1 billion tons of water to other economies, 94.6% of which was transported to other provinces. This phenomenon is contradictory to the comparative advantage theory. Water is a critical input in the production of commodities, but it is only one factor from the perspective of generalized trade. It is rich in energy resources but imports a large amount of external virtual energy from other provinces. Many labors come to Xinjiang both in physical and virtual senses. This situation indicates that generalized trade plays a more important role, and suggests that it should continue to improve its industrial system and optimize its business environment. [ABSTRACT FROM AUTHOR]

Freshwater is fundamental for all aspects of human well-being and sustainable development. The supply of freshwater resource largely depends on the natural water cycle, leading to extremely unequal distribution over the world. This uneven distribution and increasing freshwater demand results in spatial and temporal physical freshwater shortage. By discussing the limitations of desalination techniques and the shortcomings of existing pathways for freshwater transfer including water transfer projects, bottled water market, and virtual water trade, we suggest that international freshwater trade as an additional pathway is necessary. The analysis of the cost structure of freshwater production and transportation and the hypothetical examples between potential exporting and importing countries show the feasibility of international freshwater trade. The establishment of a global freshwater market is confronted with six challenges, namely, natural sustainability, ecological safety, opinions of stakeholders, market access mechanism, pricing mechanism, and infrastructure system. We conclude that a global freshwater market is expected to make contributions to achieving SDG 6 by mitigating spatial and temporal freshwater scarcity and by resolving transboundary freshwater conflicts and managing local freshwater consumptions. [ABSTRACT FROM AUTHOR]

Global water resources are constantly flowing in the process of industrial trade, and changes in water resource production and consumption demand not only affect the total consumption and flow pattern of water resources but also the stable development of the economic system. How to achieve the goals of water conservation and the spatial balance of water resources while promoting social and economic stability and sustainable development has become an important prerequisite for the coordination and sustainable development of water resources and economic systems. Therefore, this paper starts with the industrial correlation effect of the downstream consumption side of the industrial linkage path, and uses the multi-regional input–output model, power-of-pull approach and industrial correlation effect model to deeply analyze the important path of the coordinated and sustainable development of China's water resources and economic system. The results show that: The relevant sectors of industry and service always have a stable and low pull index on the water consumption end, which had a small pulling effect on the water production end. Moreover, the flow of the industrial virtual water trade linkage path did not increase when total economic output value increased, making it an important development industry for the coordinated development of water resources and economic systems. Additionally, comparing the virtual water flow and flow direction of the industrial linkage path with the industry's total economic and trade output value, it is found that the unreasonable industrial pulling effect and pushing effect have become one of the important obstacles affecting the spatial balance of water resources and coordinated economic development of China. Therefore, the regulation of virtual water trade pattern can not only be judged from the flow of the link path, but also need to combine the different correlation effects in the industrial link path to promote the coordinated and sustainable development of water resources and economic system more reasonably. [ABSTRACT FROM AUTHOR]

The virtual water trade in a region is affected by both natural factors and human activities. In order to quantitatively study the influence of human activities to the virtual water trade, a new quantitative comparative analysis method was proposed in this paper. By adjusting the natural climate factors into a uniform standard, this paper quantitatively analyzed the impact of the increase and decrease of external water diversion and the strictest water resources management policies on the virtual water trade in agricultural and industrial sectors by year and inter-year. Taking Shandong Province as an example, this study applied this method to make a quantitative analysis of virtual water trade in Shandong Province in the past 20 years. The results show that with the development of economy, the net output curves of agricultural and industrial virtual water are U-shaped and irregular inverted U-shaped, respectively. Virtual net water output can adversely affect the local water environment. In 1997, when the Yellow River stopped flowing, the decrease of water diversion reduced the net virtual water output of agriculture and industry by 20.13% and 49.67%, respectively. In 2017, the input of the South-to-North Water Diversion Project increased the net virtual water output of agriculture and industry by 1.32% and 41.99%, respectively, compared with that without the diversion, while the implementation of the strictest water resources management policy reduced it by 10.01% and 20.39%, respectively. [ABSTRACT FROM AUTHOR]

This paper examines intraregional bilateral trade in virtual water embedded in cereal flows between the Southern Africa Development Community (SADC) states. A gravity model is employed to examine whether annual bilateral trade depends on differences in water endowments, but also includes socio-economic and political determinants that affect trade. There is evidence that the abundance of water resources in a country influences trade for a product that is water dependent. Thus, the adverse effect of water scarcity in a country may be ameliorated by encouraging exports of water-intensive cereal crops where water is in abundance and imported where water is scarce. [ABSTRACT FROM AUTHOR]

At present, China is facing a relatively serious water security problem, and virtual water trade is an important means to alleviate the shortage of water resources. It is of great practical significance for China to analysis of the multi-scale near-long-distance flow of virtual water between regions. In this paper, the multi-regional input-output model was used to measure the virtual water near-long-range transfer of 17 departments in eight regions in 2012 and 2017 in China. The measured results are further discussed in the context of K-means and structural decomposition analysis (SDA) methods. The results show that from 2012 to 2017, the overall trend of interregional virtual water flow and import and export volume of various regions and departments in China showed a downward trend, and there were significant differences in inflow, outflow, and distribution. In 17 sectors, the agricultural sector has a much higher virtual water flow than other sectors, particularly in the north-west and central regions. In addition, the food and tobacco industry and construction industries in most regions also have the characteristics of high outflows. This paper argues that China should Fully exploit the effect of industrial structure on the suppression of virtual water rise. At the same time, it is necessary to improve the virtual water trade pattern, especially the virtual water trade pattern of the agricultural sector, and then gradually optimize the distribution pattern of regional water resources in China. [ABSTRACT FROM AUTHOR]

Virtual water trade can generate an aggregate value gain or loss when there is a regionally disparity in the value of water resources. This paper proposes a novel integrated model to evaluate the impact of virtual water trade on the gain and loss in both environmental and economic dimensions. Environmentally, when virtual water flows from regions rich in water to regions short of water, the scarcity of water resources at the aggregate level is alleviated and positive gains are obtained. Economically, as virtual water is transferred from economically less developed regions to those that are economically developed, the marginal economic value of water resources is enhanced, resulting in a positive gain. China is characterized by significant disparities in the degree of water scarcity and the level of economic development in different areas of the country. This study therefore focuses on China as a case of how interregional virtual water trade leads to a loss or gain in aggregate value. We employ a Multi-regional Input–Output model to analyze the virtual water flows within China and adopt the Data Envelopment Analysis to evaluate the water shadow price. Results show that the virtual water flow in China in 2015 was mostly from water-scarce to water-rich regions, resulting in a loss of 8 billion m3 of scarce water; however, at the same time, economically developed areas received large amounts of virtual water from less developed areas, thereby generating a net economic gain of 8.5 trillion CNY. In particular, the virtual water trade from Heilongjiang to Shandong yielded the largest of environmental gains, saving 1.65 billion m3 of scarce water, and the virtual water trade from Xinjiang to Guangdong produced the largest of economic gains, hitting 479 billion CNY. This paper aims to serve as an inspiration for regional, national and even global virtual water trade practices. [ABSTRACT FROM AUTHOR]

As a semi-arid/arid country located in the northwest of Africa, Morocco is facing serious water scarcity driven by the dual stresses of decreasing availability of water resources and increasing water demands. Virtual water trade could be an effective tool to alleviate water scarcity. The paper presents an analysis of the relationships between agrarian productions, foreign trade, and the water sector in Morocco by deriving a comprehensive estimate of virtual water export and import in Morocco's foreign trade of 40 crop products during the period from 2000 to 2017. Our objectives include determining the intensity of water consumption of exported and imported crop products and quantifying the water consumed and saved, respectively, by locally producing and importing these products. To this end, FAO's Penman-Monteith climate model was used to estimate crop water requirements based on data on meteorological factors. The results show that Morocco was a net virtual water importer during the study period. The deficit was 595.74 Gm3. The tendency of total virtual water export was on a rising trend, while the total virtual water import was on a downward trend. The main exported virtual water was from vegetables (68.87 Gm3, 72.47%) and the main imported virtual water was from cereals (679.68 Gm3, 98.4%). Regarding crop product's water intensity, we found that the exported crop products were excessively concentrated on water-intensive products such as mandarins and clementines, figs, oranges, apricots, plums, citrus fruits, olives, tomatoes, asparagus, peas, and artichokes. On the other hand, the agricultural policy of 2009–2020 increased the production of water-intensive products. This finding seems to be going against the virtual water trade theory, which states that water-poor countries should import water-intensive products and produce local products with lower water requirements. [ABSTRACT FROM AUTHOR]

Irrigated agriculture is the highest water user in Sri Lanka. Therefore, when there is an increasing demand of other sectors such as drinking, industries, environment etc., it is required to reallocate water from the irrigated agriculture sector to meet this increased demand. However, this needs to be done while ensuring the food security of the nation using the virtual water concept, which is defined as the embedded water in a product. Therefore, this study is conducted with the objective of assessing the, i) virtual water of agricultural production, ii) virtual water of food imports and exports, iii) virtual water trade and iv) water footprint of the nation. The data on crop water requirements, extent cultivated, imported, and exported agricultural products were collected from secondary sources and the analysis was made according to the globally accepted methodology. The annual virtual water value of domestic production is found to be 8.13 Gm³ of which paddy contributes 54.7%. The average virtual water value of paddy in Maha season is less than that in the Yala season whilst the virtual water value of paddy in minor schemes are higher than that in the major schemes in both seasons implying that more water is required to produce 1kg of paddy in minor schemes. The net import of Virtual water is 3.8 Gm³ per year. The water footprint of Sri Lanka is 12.0 Gm³ per year with a per capita water footprint of 535.22 m3 per year. The water required for domestic production is about 15.8% of the surface runoff of the country indicating the possibility of meeting the food demand with the available water resources. [ABSTRACT FROM AUTHOR]

International trade can spur economic growth, but it can also deplete the water resources needed to produce traded goods. This is crucial for Egypt as a lower-middle income country where boosting agricultural exports is encouraged to promote the sustainable agriculture development strategy. The objective of this paper was to quantify Egypt's virtual water flows contributing to agricultural trade with one of its main trading partners, the European Union. We considered calculating virtual water of exports since 2001 as it represents Egypt-EU's implementation of the association agreement. We focused on the five governorates of the Nile Delta. These governorates are major producers of the five major crops exported to the European Union. This study used long-term trade trends, and changes in crop composition to analyze the implications for virtual water outflows and economic water use efficiency. By decomposing the virtual water of exports, we were able to identify the trend of virtual water outflows and the factors affecting this trend. From both an economic and water perspective, our results suggest that adopting a policy aimed at saving water resources at the national level and focusing on high-yield exports at the international level will promote the development agenda of Egypt. [ABSTRACT FROM AUTHOR]

In order to promote the rational allocation of water resources in Shaanxi Province and the Yellow River Basin and ensure regional water security, based on virtual water theory and inter-regional input-output table of China, this paper calculated the water consumption coefficients of three major industries virtual water volume in Shaanxi Province, and the virtual water trade volume between this province and other provinces in China in 2007, 2010, 2012, 2015 and 2017 with the help of input-output model, and explored the main factors affecting the change of virtual water volume in Shaanxi Province by using gray correlation model. Further, the inter-industry allocation characteristics of virtual water in Shaanxi Province were analyzed and the virtual water trade network between Shaanxi Province and other provinces were established. The results show that a) the coefficient of direct water consumption and complete water consumption coefficient of the primary industry in Shaanxi Province are higher than that of the secondary and tertiary industries, but all show a decreasing trend over this time, indicating that the province’s water use efficiency are constantly improving. b) The primary and secondary industries account for the majority of the virtual water supply in Shaanxi Province, and the level of agricultural technology, population size, urbanization rate, food production, industry and construction development level are the main factors affecting the virtual water supply of the primary and secondary industries in the province. c) More than 70% of the virtual water in Shaanxi Province are consumed by itself and transported to other provinces mainly are Guangdong, Shanghai, Tianjin, Hebei, Shandong, Shanxi, Inner Mongolia and Henan provinces. It mainly exports to the primary industry. More than 90% of the virtual water input derives from the secondary and tertiary industries of Jiangsu, Guangdong, Shanghai, Anhui, Zhejiang and Hunan provinces. d) Shaanxi Province has maintained net input state for a long time in the inter-provincial trade; compared with the actual water resources trade net virtual water trade between Shaanxi Province and Sichuan, Liaoning, Jilin and other provinces is unreasonable. Shaanxi Province should promote the spatial and temporal matching of virtual water and physical water by adjusting the industrial structure and optimizing the inter-provincial trade network, which is of great significance for the rational use of water resources at the Yellow River Basin scale and even at the national scale. [ABSTRACT FROM AUTHOR]

From the perspective of value-added trade, this paper divides the virtual water consumption and trade in different provinces of China into five major paths according to the input-output relationship. In 2012 and 2015, most provinces' water resources were implicitly used in the final products to meet the local demand. In addition, the volume of virtual water trade in the complex domestic value chain is greater than that in the traditional domestic trade value chain and the simple domestic trade value chain. In both years, judging from the sum of virtual water trade volumes in the three major value chains, there is virtual water net inflow in Beijing-Tianjin and the northern, eastern and southern coastal areas, and virtual water net outflow in the northeast, central and northwest areas. In the course of this research, the virtual water net outflow turned into net inflow in the southwestern area. [ABSTRACT FROM AUTHOR]

Limited and declining water resources, increasing demand of water resources from different sectors, has posed a major challenge for maintaining water sustainability and thus overall sustainability for a populous and water-scarce country like India. Over extraction and changing climate have put additional pressure to maintain water sustainability. Therefore, there is a need for proper planning of utilization and management of water resources. Recently, virtual water trade has received much attention and become an important tool for balancing the water budget. On the other hand, virtual water trade may also adversely affect the water balance of the exporter's country as well as the economy. Analysis of the virtual water trade with its implications for water resources is missing; hence, there is a need for such analysis that will help in management of water resources. In this study an attempt is made to present a quantitative analysis of the virtual water trade and its implications for water sustainability. For this study, the rice crop is considered only due to its characteristics as rice is a major water consumer crop and water exporter crop from India. HIGHLIGHTS Total water required for production of rice is 318 billion m3, 16.67% of total water available.; Virtual water export is about 32 billion m3, while the virtual water import is negligible.; The net virtual water content export is about 4.8 billion m3 which is irreversible in the system and leads to loss of water sustainability.; The net export of virtual water is about 32 billion m3, a large volume of water export.;

Water resources are under increasing pressure from population growth, socio-economic development, and climate change. The main user of freshwater is the agriculture sector, accounting for 70–80% of global water use. Consequently, increasing water productivity and reducing water use in this sector are vital for alleviating water scarcity. It has been alleged that domestic or international trade of water-consumed products from wet-provinces or countries to arid and semi-arid provinces or countries is one possible path to mitigate water shortage. In this regard, virtual water flows and their determinants in Iran are investigated in this paper. This study examines the main determinants of bilateral virtual water flows associated with international trade in agricultural goods among Iran and other countries using a gravity model of trade. The impacts of climate change and socio-economic change scenarios on the virtual water trade are simulated. The result of the gravity model indicated that bilateral virtual water trade flows are influenced by the classical determinants and all the mass-related variables (gross domestic product and population) are significant with expected signs. Finally, the result obtained from the simulation of climate and socio-economic change scenarios showed that under the pessimistic scenario of climate change and population growth rate of 0.98 and 0.44%, VW trade between Iran and other countries would increase by 41 and 66% in the periods of 2016–2045 and 2070–2099, respectively. As a consequence, identifying the appropriate countries for business interactions and adopting effective trade policies are very important and need attention soon. HIGHLIGHTS Bilateral virtual water trade flows are influenced by the classical determinants and all the mass-related variables (gross domestic product and population).; The size of the future virtual water flows was predicted under the climate and population change scenarios.; The average annual temperature and the population of Iran, as the determinants of virtual water flows, have a positive and significant effect on the net virtual water flows.;

The original intention of virtual water trade (VWT) is to help water-scarce areas adjust the crop trade structure to alleviate the water shortage problem. However, China's existing virtual water trade (VWT) must effectively alleviate the problem. This paper's structural features and stability of the VWT network (VWTN) in China's major crop trade between 2000 and 2017 were characterized using complex network theory. The results in terms of time scale showed that the total content of VW in China's major crops increased by ~23.6% for 18 years. Trade relations among most regions remained stable, whereas a few areas changed: Jilin, Henan, and Heilongjiang played essential roles in the output network, and so did Guangdong, Shanghai, and Fujian in the input network. Attributed to policy adjustment, Henan and Jilin became more prominent in the output network with the gradual decline of Jiangsu's position. Regarding spatial scale, the cumulative distribution of degrees consistent with the power–law relationship showed high variability and vulnerability of China's VWTN, especially when nodes were weighted. Since areas with more VWT partners/content provided connectivity to those with fewer partners/content, it is worthwhile to focus on developing protection policies for critical areas. The virtual water trade from North China (water-poor) to South China (water-rich) is contrary to the distribution of water resources. A similar situation showed in a global world that the long-term supply relationship would aggravate the water resources shortage and food security. Furthermore, we suggest combining network theory and VWT to lay the foundation for the invulnerability research of VWTN and the optimal regulation of crops. [ABSTRACT FROM AUTHOR]

The world's sustainable growth is being severely hampered by the inefficient use of water resources. Despite the widely acknowledged importance of trade in global and regional water and food security, societal reliance on local production, as well as international trade, remains inadequately assessed. Therefore, using South Korea as a case study, this study fills in this research gap by applying the virtual water concept, the logarithmic mean divisia index (LMDI) method, and the Tapio decoupling model. The virtual water concept was used to estimate South Korea's net virtual water trade for major grain crops from 1992 to 2017. Then, the LMDI method was utilized to assess the driving factors causing changes in net virtual water trade. Lastly, the Tapio decoupling model was used to investigate the decoupling relationships between economic growth and the driving factors of net virtual water trade. The results showed that South Korea remains a net importer of virtual water flows with respect to grain crops, with an average import of 16,559.24 million m3 over the study period. In addition, the change in net virtual water trade could be attributed to the water intensity effect, product structure effect, economic effect, and population effect. However, water intensity and economic effects were the major decisive factors for decreases and increases in net virtual water trade, respectively, while the population and product structure effects had minor positive influences on the net virtual water trade. Furthermore, water intensity and economic growth showed a strong decoupling in most periods, while the decoupling state between product structure and economic growth was observed as expansive negative decoupling. Likewise, population size and economic growth showed a weak decoupling in most periods. The results reveal South Korea's status as it concerns the virtual water trade of grain crops, thus providing valuable insights into the sustainability of trade activities for the management of local water resources. [ABSTRACT FROM AUTHOR]

Central Asia exports large amounts of virtual water through agricultural trade, a key factor for overexploitation of water resources in the region. Most studies analyze Central Asia's virtual water outflows to the outside world, while ignore the agricultural trade within the region and the varying impacts of virtual water flows on the individual countries. In this study, the changes in virtual water flows embedded in trade with outside regions (external) and Central Asia countries (internal) were analyzed for the period 2000–2018 for wheat, cotton, and livestock. The results show that while Central Asia exported, respectively, 194.3 and 101.8 km3 of virtual water to the outside world through cotton and wheat trade, it imported 53.7 km3 of virtual water via livestock trade. Also, while cotton‐based virtual water outflows decreased, wheat‐based virtual water outflows increased. Total virtual water flows in internal trade reached 71.2 km3, with flow originating mainly from Kazakhstan and heading to other four countries through wheat trade.Kazakhstan was the largest net exporter of virtual water through wheat trade, Uzbekistan was the second‐largest net exporter through cotton trade. Green water (precipitation water used by crops) was dominant in virtual water flow related to wheat and blue water (surface water or groundwater used by crops) was dominant in virtual water flow related to cotton. Uzbekistan and Turkmenistan were most directly influenced by the virtual water trade. [ABSTRACT FROM AUTHOR]

Improper use of water resources for agricultural production has led to a global decline in freshwater resources because more than 80% of the world's freshwater resources are used for agricultural purposes. Most countries can compensate for the water restrictions for food production by importing virtual water through international trade of agricultural commodities by which virtual water is transferred from the production regions to the consumption regions. The present research aimed to investigate the possibility of national savings in freshwater consumption in Iran by importing virtual water of agricultural products (cereals) over the period of 2001–2018. The results show that importing cereals has contributed to national savings on freshwater consumption in Iran, amounting to 21 167 million m3 per year. The total saving is estimated at 381 011 million m3 out of which 53.18% is green water, 34.09% is blue water, and 12.73% is grey water. [ABSTRACT FROM AUTHOR]

This study reviews groundwater status and management based on the existing literature regarding its resource endowment, hydrogeology, challenges and issues of management and policy suggestions for India. Efficient management requires decoupling groundwater rights from land-ownership rights, changes in electricity pricing and metering, aquifer-based plans for storage and replenishment, and empowerment of participatory irrigation management for local management. Issues of water-food-energy nexus, climate change, carbon footprint of groundwater extraction and virtual water trade are also important for ensuring sustainable management of groundwater resources. [ABSTRACT FROM AUTHOR]

In order to help solve the water resources issues that restrict the high-quality development of the Yellow River Basin, based on the multi-regional input-output table of China, this paper calculated the virtual water of the nine provinces in the Yellow River Basin from 2012 to 2015 by building a multi-regional input-output（MRIO） model, and analyzed its flow pattern and trend. The results show that a)the Yellow River Basin changes from virtual net water outflow area to inflow area between 2012 and 2015. The upstream area is always the virtual water outflow area, the downstream area is always the virtual water inflow area, and the midstream area is transformed from the virtual water inflow area to outflow area. The flow pattern of virtual water is not coordinated with water resources. b)Virtual water flow sectors have great industry similarities. However, there are differences in the trade structure of virtual water in different regions. c)In the virtual water trade within the Yellow River Basin, Shaanxi, Shanxi and Henan are the main virtual water consumers, while Qinghai and Ningxia are the main virtual water suppliers. The virtual water flowing out of the Yellow River Basin mainly flows to the northeast and Beijing-Tianjin-Hebei region. Finally, the suggestions are proposed to promote the optimization and allocation of water resources and help the high-quality and coordinated development in the Yellow River Basin. [ABSTRACT FROM AUTHOR]

Attention to water resources and consumption in Iran's industrial sector is important due to the existence of severe tensions in the country's water resources. Therefore, the purpose of this study is to evaluate the virtual water trade in the oil industry of Iran. For this purpose, the technical-basic approach has been used to measure virtual water and the special water demand and virtual water trade of Iran's oil sector has been calculated from 1978 to 2019. The results show that due to the high volume of oil exports, Iran is a net exporter of virtual water. The amount of water consumed in the oil industry and the process of extraction and production of crude oil in the years under review averaged 594 million cubic meters per year and the amount of virtual water that left the country following the export of crude oil in these years averaged 356 million cubic meters per year. Also, the export value of virtual water in the oil sector has a value of 1838 thousand Rials per cubic meter. To manage the country's water resources and the leading crises in this sector of the industry, it is possible to greatly increase water efficiency in this sector by modifying production processes and updating equipment, facilities, and methods used to optimally consume water in this sector. .

With water scarcity increasingly becoming a growing global risk, it is prevalent to explore water supply-demand interaction within and beyond national borders driven by global virtual water trade and its effects on water sustainability. However, there is little study on system integration of differential environmental impacts of various types of trade. Based on metacoupling framework highlighting human-nature interactions across space- within a place (intracoupling), between adjacent places (pericoupling), and between distant places (telecoupling), this study quantified the linkages and intensities of three kinds of coupling processes during global virtual water trade for the first time. Correspondingly, water stress changes under a set of trade scenarios were evaluated based on the indicator of UN SDG 6.4.2 to distinguish the influence of trade taking place on different spatial scales. Results show that during 2005–2015, local water resources supported 80% of global water consumption. Distant virtual water import was about 5 times in volume as large as adjacent virtual water import, alleviating 99.8% of global average water stress. Virtual water trade reduced water stress in 86% of developed countries and increased that in 71% of developing countries in 2005. Owing to trade, water stress in many countries with poor water resources endowment declined while that of many with relatively good endowment went up from 2005 to 2015. Our findings can help to systematically understand the influence of virtual water trade on water stress change and provide scientific guidance for sustainable water management and regional regulations.

A dynamic multi-region computable general equilibrium (CGE) model is used to analyze virtual water and its effect in the Huaihe River basin, which includes Jiangsu, Anhui, Shandong and Henan provinces. The baseline scenario was first constructed to describe the trade situation and virtual water among different regions and sectors from 2009–2020. Then two hypothetical policy scenarios were set to analyze the economic, water consumption and virtual water trade impacts under different policy shocks. The results show that (1) the Huaihe River basin was a net virtual water outflow region, with 13.977 × 109 m3 virtual water transferred outside the river basin in 2009, and 26.653 × 109 m3 VW transferred to outside in 2020. Jiangsu is the largest virtual water outflow province (mainly flows to outside), followed by Anhui. Anhui suffers from severe water shortage, but provides a net virtual water outflow to Henan, Jiangsu and Shandong and outside; (2) reducing Anhui's agricultural output (S1 scenario) and Anhui's agricultural virtual water outflow (S2 scenario) can not only reduce virtual water trade but also save water, but S1 scenario reduced net virtual water outflow by more, and saved more water. S1 had a positive effect on gross domestic product (GDP), but reduced the employment rate. HIGHLIGHTS Role of VWT analyzed using a CGE.; CGE based on 12 years of data (2009–2020).; VW study not only focused on agriculture, but also included industry and service sectors.; Two hypothetical scenarios were set to analyze the economic, water consumption and VWT impact.; Assessment of VW will change water usage and trade in different upstream and downstream regions of the Huaihe watershed.;

As a semi-arid/arid country located in the northwest of Africa, Morocco is facing serious water scarcity driven by the dual stresses of decreasing availability of water resources and increasing water demands. Virtual water trade could be an effective tool to alleviate water scarcity. The paper presents an analysis of the relationships between agrarian productions, foreign trade, and the water sector in Morocco by deriving a comprehensive estimate of virtual water export and import in Morocco’s foreign trade of 40 crop products during the period from 2000 to 2017. Our objectives include determining the intensity of water consumption of exported and imported crop products and quantifying the water consumed and saved, respectively, by locally producing and importing these products. To this end, FAO’s Penman-Monteith climate model was used to estimate crop water requirements based on data on meteorological factors. The results show that Morocco was a net virtual water importer during the study period. The deficit was 595.74 Gm3. The tendency of total virtual water export was on a rising trend, while the total virtual water import was on a downward trend. The main exported virtual water was from vegetables (68.87 Gm3, 72.47%) and the main imported virtual water was from cereals (679.68 Gm3, 98.4%). Regarding crop product’s water intensity, we found that the exported crop products were excessively concentrated on water-intensive products such as mandarins and clementines, figs, oranges, apricots, plums, citrus fruits, olives, tomatoes, asparagus, peas, and artichokes. On the other hand, the agricultural policy of 2009–2020 increased the production of water-intensive products. This finding seems to be going against the virtual water trade theory, which states that water-poor countries should import water-intensive products and produce local products with lower water requirements.

Study region: The Yellow River Basin (a water-deficient region) in China. Study focus: To establish whether the virtual water trade (VWT) is beneficial for water-deficient regions we conducted an integrated assessment of the local and distant VWT of the Yellow River Basin (YRB). We adopted a modified input–output analysis model and applied multiregional input–output tables of 31 provinces in China (2017) to estimate the dependence of the YRB on water from other regions and to determine the VWT status. We calculated the total water consumption coefficient of 29 sectors in the YRB, investigated the water-use intensity of various sectors, and analyzed the water footprint and per capita usage of each province. Furthermore, we revealed the VWT among downstream, midstream, and upstream regions of the YRB. New hydrological insights for the region: This study revealed that virtual water flow is unidirectional from downstream and midstream regions to upstream regions, and that the trade structures among these three regions of the YRB differ notably, which has rarely been addressed in previous literature. Furthermore, the VWT exacerbates water resource shortages in the YRB. The irrational industrial structure is the main reason for the need for transfer of water resources. This information could inform the development of effective policies both for alleviating regional water shortages and for developing a viable virtual water strategy for the YRB.

The world’s sustainable growth is being severely hampered by the inefficient use of water resources. Despite the widely acknowledged importance of trade in global and regional water and food security, societal reliance on local production, as well as international trade, remains inadequately assessed. Therefore, using South Korea as a case study, this study fills in this research gap by applying the virtual water concept, the logarithmic mean divisia index (LMDI) method, and the Tapio decoupling model. The virtual water concept was used to estimate South Korea’s net virtual water trade for major grain crops from 1992 to 2017. Then, the LMDI method was utilized to assess the driving factors causing changes in net virtual water trade. Lastly, the Tapio decoupling model was used to investigate the decoupling relationships between economic growth and the driving factors of net virtual water trade. The results showed that South Korea remains a net importer of virtual water flows with respect to grain crops, with an average import of 16,559.24 million m3 over the study period. In addition, the change in net virtual water trade could be attributed to the water intensity effect, product structure effect, economic effect, and population effect. However, water intensity and economic effects were the major decisive factors for decreases and increases in net virtual water trade, respectively, while the population and product structure effects had minor positive influences on the net virtual water trade. Furthermore, water intensity and economic growth showed a strong decoupling in most periods, while the decoupling state between product structure and economic growth was observed as expansive negative decoupling. Likewise, population size and economic growth showed a weak decoupling in most periods. The results reveal South Korea’s status as it concerns the virtual water trade of grain crops, thus providing valuable insights into the sustainability of trade activities for the management of local water resources.