Linking water resources to food security through virtual water

The largest use of global freshwater resources is related to food production. While each day we drink about 2 liters of water, we consume (eating) about 4000 liters of “virtual water”, which represents the freshwater used to produce crop-based and livestock-based food. Considering human water consumption as a whole, most part originates from agriculture (85.8%), and only minor parts come from industry (9.6%) or households (4.6%). These numbers shed light on the great pressure of humanity on global freshwater resources and justify the increasing interest towards this form of environmental impact, usually known as “water footprint”. Virtual water is a key variable in establishing the nexus between water and food. In fact, water resources used for agricultural production determine local food availability, and impact the international trade of agricultural goods. Trade, in turn, makes food commodities available to nations which are not otherwise self-sufficient, in terms of water resources or food, and it establishes an equilibrium between food demand and production at the global scale. Therefore, food security strongly relies on international food trade, but also on the use of distant and foreign water resources, which need to be acknowledged and investigated. Virtual water embedded in production and international trade follows the fate of food on the trade network, generating virtual flows of great magnitude (e.g., 2800 km^3 in 2010) and defining local and global virtual water balances worldwide. The resulting water-food nexus is critical for the societal and economic development, and it has several implications ranging from population dynamics to the competing use of freshwater resources, from dietary guidelines to globalization of trade, from externalization of pollution to policy making and to socio-economic wealth. All these implications represent a great challenge for future research, not only in hydrology but in the many fields related to this interdisciplinary topic. Virtual water and water footprint accounting provide the tools for understanding such implications and to describe, quantify, and investigate the inextricable link existing between water resources and food securit

Propagation of crises in the virtual water trade network

The international trade of agricultural goods is associated to the displacement of the water used to produce such goods and embedded in trade as a factor of production. Water virtually exchanged from producing to consuming countries, named virtual water, defines flows across an international network of “virtual water trade” which enable the assessment of environmental forcings and implications of trade, such as global water savings or country dependencies on foreign water resources. Given the recent expansion of commodity (and virtual water) trade, in both displaced volumes and network structure, concerns have been raised about the exposure to crises of individuals and societies. In fact, if one country had to markedly decrease its export following a socio-economical or environmental crisis, such as a war or a drought, many -if not all- countries would be affected due to a cascade effect within the trade network. The present contribution proposes a mechanistic model describing the propagation of a local crisis into the virtual water trade network, accounting for the network structure and the virtual water balance of all countries. The model, built on data-based assumptions, is tested on the real case study of the Argentinean crisis in 2008-09, when the internal agricultural production (measured as virtual water volume) decreased by 26% and the virtual water export of Argentina dropped accordingly. Crisis propagation and effects on the virtual water trade are correctly captured, showing the way forward to investigations of crises impact and country vulnerability based on the results of the model propose

Stochastic description of infiltration between aquifers

Aim of this work is to propose a stochastic description of the leakage between two aquifers separated by a semi-permeable layer with low hydraulic conductivity. The source of uncertainty here considered is the random fluctuation of the phreatic surface of surficial aquifer, originated from random rainfall events. The study focuses on an area surrounding a pumping well penetrating the deep aquifer and impacting its piezometric level, where infiltration from the surficial aquifer can be more harmful. Closed form expressions for the leakage between the surficial and the deep aquifer are used to obtain the long-term probability distribution of leakage flow rate, assuming the shallow phreatic surface dynamics modeled with a Poisson- driven stochastic process. A sensitivity analysis is performed to verify the variability of the probability distribution of leakage within the range of feasible parameter values, then the stochastic model is applied to three field cases where time series of the piezometric levels of the phreatic aquifer are available. Results show that the induced variability of the discharge flowing between aquifers is remarkable and that in general it cannot be neglected despite the low hydraulic conductivity of the semi-permeable layer. The proposed probabilistic model is a useful tool for evaluating the risk associated to contaminant transport into deep aquifers and its fate in relation to groundwater withdrawal

WEIRD Testbeds with Fixed and Mobile WiMAX Technology for User Applications, Telemedicine and Monitoring of Impervious Areas

Wireless Metropolitan Area Networks based on IEEE 802.16d/e standards are soon to be deployed in several countries. However, there is lack of published literature with results from actual test¬beds. This paper introduces the work done in the EU Sixth Framework Programme Project WEIRD to design and set up WiMAX testbeds in four EU countries. We describe the method¬ology followed, detail our implementation and present results from the testbeds, as deployed in the first phase of WEIRD. The testbeds are used to demonstrate how WiMAX technology can be used to extend the connectivity of the pan-European data com¬munications network (GEANT2) to isolated and impervious ar¬eas and, furthermore, to assure end-to-end quality of service to novel applications

WEIRD Testbeds with Fixed and Mobile WiMAX Technology for User Applications, Telemedicine and Monitoring of Impervious Areas

Wireless Metropolitan Area Networks based on IEEE 802.16d/e standards are soon to be deployed in several countries. However, there is lack of published literature with results from actual test¬beds. This paper introduces the work done in the EU Sixth Framework Programme Project WEIRD to design and set up WiMAX testbeds in four EU countries. We describe the method¬ology followed, detail our implementation and present results from the testbeds, as deployed in the first phase of WEIRD. The testbeds are used to demonstrate how WiMAX technology can be used to extend the connectivity of the pan-European data com¬munications network (GEANT2) to isolated and impervious ar¬eas and, furthermore, to assure end-to-end quality of service to novel applications.SIGARCH, Create-NetPublishedInnsbruck, Austria1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attiveope

Food-water security and virtual water trade in the Middle East and North African region

The purpose of this study is to analyse the political economy of food-water security in the water-scarce Middle East and North African (MENA) region. Food-water identifies the water needed to produce food commodities and accounts for 90% of consumptive water use of societies. Given the large water volumes required for food production, water and food security in the region are very closely linked. The study deploys the lens of virtual water trade to determine how the region’s economies have met their rising food-water requirements over the past three decades. MENA food-water security is framed in the wider context of international trade, showing that global economic systems have enabled the MENA countries to access global water resources and to effectively mitigate local water deficits. The study shows that the region’s water and food security currently depend to a considerable extent on water from outside the region, ‘embedded’ in food imports and accessed through trade. The proposed analysis includes blue (surface and ground-) water and green (soil) water resources and it shows that the region’s economies have all become net virtual water importers, with larger fluxes mainly associated with the trade in crops. The study also shows that the largest share of the virtual water import of the region is green and originates from Brazil, the USA and Russia, while a large fraction of virtual water export remains within the region. The dependency of each country on virtual water import is quantified with a specific indicator revealing the greater dependency on external water resources of the most developed economies in the region

Food-water security and virtual water trade in the Middle East and North African region

The purpose of this study is to analyse the political economy of food-water security in the water-scarce Middle East and North African (MENA) region. Food-water identifies the water needed to produce food commodities and accounts for 90% of consumptive water use of societies. Given the large water volumes required for food production, water and food security in the region are very closely linked. The study deploys the lens of virtual water trade to determine how the region’s economies have met their rising food-water requirements over the past three decades. MENA food-water security is framed in the wider context of international trade, showing that global economic systems have enabled the MENA countries to access global water resources and to effectively mitigate local water deficits. The study shows that the region’s water and food security currently depend to a considerable extent on water from outside the region, ‘embedded’ in food imports and accessed through trade. The proposed analysis includes blue (surface and ground-) water and green (soil) water resources and it shows that the region’s economies have all become net virtual water importers, with larger fluxes mainly associated with the trade in crops. The study also shows that the largest share of the virtual water import of the region is green and originates from Brazil, the USA and Russia, while a large fraction of virtual water export remains within the region. The dependency of each country on virtual water import is quantified with a specific indicator revealing the greater dependency on external water resources of the most developed economies in the region