The argument that economies that face acute water scarcity problems can and should meet their water demand for food through cereal imports from water-rich countries; and that virtual water trade can be used to achieve water securities has become dominant in global water discussions. Analysis of country level data on renewable freshwater availability and net virtual water trade of 146 nations across the world shows that a country's virtual water trade is not determined by its water situation. Some countries have the advantage of high "economic efficiency" in food production and have surplus water, but resort to food import, whereas some water scarce countries achieve high virtual water trade balances. Further analysis with a set of 131 countries showed that virtual water trade increased with increase in gross cropped area. This is because of two reasons: First, when access to arable land increases, the ability to utilize available blue water for irrigation increases. Second, increasing access to arable land improves the access to water held in the soil profile as "free good", a factor not taken into account in assessing water availability. Hence, many of the humid, water-rich countries will not be in a position to produce surplus food and feed the water scarce nations; and virtual water often flows out of water-poor, land rich countries to land-poor water-rich countries. This means that "distribution of scarcity" and "global water use efficiency", are goals that are difficult to achieve through virtual water trade in a practical sense. For a water-poor, but land rich country, virtual water import offer little scope as a sound water management strategy as what is often achieved through virtual water trade is improved "global land use efficiency". The important policy inferences emerging from the analyses are two: First, assessing the food security challenges posed to nations in future purely from a water resource perspective provides a distorted view of the food security scenario. National policies on food security should take into account "access to arable land" apart from water availability. Second, analysis of water challenges posed by nations purely from the point of view of renewable water availability and aggregate demands will be dangerous. Access to water in the soil profile, which is determined by access to arable land, would be an important determinant of effective water availability.

The food, energy, and water (FEW) nexus has gained increased attention, resulting in numerous studies on management approaches. Themes of resource use, and their subsequent scarcity and economic rents, which are within the application domain of the World Trade Model, are ripe for study, with the continuing development of forward- and backward-facing economic data. Scenarios of future food and energy demand, relating to supply chains, as well as direct and indirect resource uses, are modelled in this paper. While it is possible to generate a substantial number of economic and environmental scenarios, our focus is on the development of an overarching approach involving a range of scenarios. We intend to establish a benchmark of possibilities in the context of the debates surrounding the Paris Climate Agreement (COP21) and the Green New Deal. Our approach draws heavily from the existing literature on international agreements and targets, notably that of COP21, whose application we associate with the Shared Socioeconomic Pathway (SSP). Relevant factor uses and scarcity rent increases are found and localized, e.g., on the optimal qualities of water, minerals, and land. A clear policy implication is that, in all scenarios, processes of energy transition, raw material use reduction, and recycling must be strengthened.

Resumen Objetivo: Proporcionar un marco conceptual de la esquematización del nexo agua-alimentos-comercio internacional utilizando el modelo actancial, basado en el análisis cualitativo de las relaciones que se presentan entre sus participantes con un enfoque integrador. Diseño metodológico: Se explica bajo la lógica del modelo actancial centrado en la descripción y clasificación de personajes, o bien, llamados actantes. El análisis se basó en la revisión de artículos que exponen el contexto y debate de los elementos del modelo actancial, que permitieran identificar las principales características que explican al actante y sus interrelaciones a través de la esquematización en el nexo de estudio. Resultados: Permiten comprender de manera esquemática y cualitativa las relaciones que subyacen entre los elementos que componen el nexo agua-alimentoscomercio internacional con una visión novedosa, argumentando el rol que desempeñan cada uno de los componentes de los actantes y los ejes del nexo. Esto es relevante debido a que la comercialización de agua virtual, puede conducir a serios problemas de dependencia hidro-alimentaria, por lo que se necesita de la formulación de políticas públicas estratégicas y efectivas en el corto y largo plazo. Limitaciones de la investigación: Se sugiere complementar esta investigación con un análisis cuantitativo bajo una perspectiva de la complejidad de redes que pueda valorar los efectos de estas interrelaciones desde una postura teórica y práctica e incorporar otros agentes que determinan la política hídrica y comercial de manera estratégica hacia una menor dependencia hidroalimentaria. Hallazgos: Estas interrelaciones son diversas e intensivas, destacando la importancia y compresión del nexo a escala global y nacional. | Abstract Purpose: To provide a conceptual framework for the schematization of the water-food-international trade nexus using the actantial model, based on the qualitative analysis of the relationships that occur among its participants with an integrative approach. Methodological Design: It is explained under the logic of the actantial model, centered on the description and classification of characters, also known as actants. The analysis was based on the review of articles that present the context and discussion of the elements of the actantial model, enabling the identification of the main characteristics that explain the actant and its interrelationships through schematization in the study’s nexus. Results: The results provide a schematic and qualitative understanding of the underlying relationships among the elements comprising the water-food-international trade nexus, offering a novel perspective and arguing for the roles played by each actant component and nexus axes. This is significant because virtual water trade can lead to serious issues of hydro food dependency, necessitating the formulation of strategic and effective public policies in both the short and long term. Research Limitations: It is suggested to complement this research with a quantitative analysis from a network complexity perspective. This analysis would allow for the assessment of the effects of these interrelationships both theoretically and practically, while also integrating other agents that strategically shape water and trade policies, aiming to reduce hydro-food dependence. Findings: These interrelationships are diverse and intensive, underscoring the significance of global as well as national scale comprehension of the nexus.

Recent years have shown increased awareness that the use of the basic resources water, food, and energy are highly interconnected (referred to as a ‘nexus’). Spatial scales are an important but complicating factor in nexus analyses, and should receive more attention – especially in the policy-oriented literature. In this paper, we ‘unpack' the nexus concept, aiming to understand the differences between water, food and energy resources, especially in terms of spatial scales. We use physical indicators to show the differences in terms of absolute magnitude of production and the distance and volume of physical trade, for seven resource categories: water withdrawal, crops, animal products, bio-energy, coal, oil, and natural gas. We hypothesize that the differences in trade extent are related to physical characteristics of these resources: we expect high priced, high density, geographically concentrated resources to be traded more and over longer distances. We found that these factors, taken together, can explain some of the differences in trade extent (and thus spatial scale involved), although for each individual factor there are exceptions. We further explore the spatial scales by showing the bidirectional physical trade flows at the continental scale for crops, animal products, bio-energy and fossil fuels. We also visualize how nexus resources are directly dependent on each other, using a Sankey diagram. Since both direct dependencies and physical trade are present, we investigate the role of resource-saving imports, which is a form of virtual trade. The resource-saving imports highlight the importance of continental and global scales for nexus analyses.

At global scale, the majority of world water withdrawal is for the agricultural sector, with differences among countries depending on the relevance of agri-food sector in the economy. Virtual water and water footprint could be useful to express the impact on the water resources of each production process and good with the objective to lead to a sustainable use of water at a global level. International trade could be connected to the virtual water flows, in fact through commodities importation, water poor countries can save their own water resources. The present paper focuses on the bilateral virtual water flows connected to the top ten agri-food products traded between Italy and China. Comparing the virtual water flow related to the top 10 agri-food products, the virtual water flow from Italy to China is bigger than the water flow in the opposite direction. Moreover, the composition of virtual water flows is different; Italy imports significant amounts of grey water from China, depending on the different environmental strategies adopted by the two selected countries. This difference could be also related to the fact that traded commodities are very different; the 91% of virtual water imported by Italy is connected to crops products, while the 95% of virtual water imported by China is related to the animal products. Considering national water saving and global water saving, appears that Italy imports virtual water from China while China exerts pressure on its water resources to supply the exports to Italy. This result at global scale implies a global water loss of 129.29millionm3 because, in general, the agri-food products are traded from the area with lower water productivity to the area with the higher water productivity.

Exploring the environmental impact of dietary consumption has become increasingly important to understand the carbon-water-food nexus, vital to achieving UN sustainable development goals. However, the research on diet-based nexus assessment is still lacking. Here, we developed an Environmentally Extended Multi-Regional Input-Output (EE-MRIO) model with compiling a global MRIO table based on the latest Global Trade Analysis Project (GTAP) 10 database, where we specifically constructed a water withdrawal account and matched it to each economy at the sectoral level. The regional heterogeneity and synergy of carbon-water nexus affected by dietary patterns in nine countries was explored. The results show that: (1) Dietary consumption is the main use of water withdrawal for each country; Japan, the US, South Korea, and India have a high per capita dietary water footprint. Mainly due to consumption of processed rice, Japan has the highest per capita value of 488 M³/year, accounting for 63.4% of the total water footprint. (2) The total dietary carbon footprints in China, India, and the US are high, which is mainly caused by the high consumption of animal products (including dairy) either due to the large population (China, India) or animal-based diet (the US). Americans have the highest per capita dietary carbon footprint, reaching 755.4 kg/year, 2.76 times that of the global average. (3) Generally, imported/foreign footprints account for a greater share in dietary water and carbon footprints of developed countries with an animal-based diet. (4) In the nexus analysis, the US, Japan, and South Korea are key-nexus countries, vegetables, fruit and nuts, tobacco and beverages, and other food products are selected as key-nexus sectors with relatively high dietary water and carbon footprint. Furthermore, dietary consumption choices lead to different environmental impacts. It is particularly important to find a sustainable dietary route adapted to each country considering that heterogeneity and synergism exist in key-nexus sectors to achieve the relevant Sustainable Development Goals.

Global food trade entails virtual flows of agricultural resources and pollution across countries. Here we performed a global-scale assessment of impacts of international food trade on blue water use, total water use, and nitrogen (N) inputs and on N losses in maize, rice, and wheat production. We simulated baseline conditions for the year 2000 and explored the impacts of an agricultural intensification scenario, in which low-input countries increase N and irrigation inputs to a greater extent than high-input countries. We combined a crop model with the Global Trade Analysis Project model. Results show that food exports generally occurred from regions with lower water and N use intensities, defined here as water and N uses in relation to crop yields, to regions with higher resources use intensities. Globally, food trade thus conserved a large amount of water resources and N applications, and also substantially reduced N losses. The trade-related conservation in blue water use reached 85km³y⁻¹, accounting for more than half of total blue water use for producing the three crops. Food exported from the USA contributed the largest proportion of global water and N conservation as well as N loss reduction, but also led to substantial export-associated N losses in the country itself. Under the intensification scenario, the converging water and N use intensities across countries result in a more balanced world; crop trade will generally decrease, and global water resources conservation and N pollution reduction associated with the trade will reduce accordingly. The study provides useful information to understand the implications of agricultural intensification for international crop trade, crop water use and N pollution patterns in the world.

Virtual water flows, incorporated in global food trade has increased the last decade. The drivers and consequences are complex. These complex relations between humans and water resources are studied from different perspectives. In this article, an overview of four such perspectives on water in global food production and trade is provided. These four perspectives are: (1) More crop per drop for increasing production, (2) Less drop per crop for reducing impacts, (3) National food security and import dependency; and (4) Local values and implications of water used in export food production. Each of the perspectives is valuable in the sense of representing different value frameworks, which represent contrasting norms and convictions, belief systems, and discourses; which are often incommensurable.

As the most populous country over the world, China has great pressure on food and resources security. In this study, we set the national economy of China as a whole system, and apply supply chains analysis based on the input-output structures, to identify the food-water linkage, food-energy linkage, and the energy-water linkage in the system. The results show that agriculture and animal husbandry contribute most use of resource in supply chains. Animal husbandry sector, agriculture, slaughtering and processing of meat contribute large amount of embodied water consumption. While agriculture, other food sector and animal husbandry sector consumes most embodied primary energy, although the direct primary energy use by animal husbandry sector is not significant. Meanwhile, by importing or exporting resources, international trade impacts on the resources flow through input-output structures. When making polices, the interactions of various resources and international trade should be considered by applying food energy water nexus (FEWN) approach.