Periodic Reporting for period 4 - CWASI (Coping with water scarcity in a globalized world) Reporting period: 2020-01-01 to 2020-12-31 Summary of the context and overall objectives of the project In the Anthropocene, the health of us humans is more closely linked than ever to the health of our planet. Food and water are paradigmatic examples of the close connection between humankind and planet health. While it is obvious that suitable food and water quantity and quality are necessary to human health, we are hardly aware of the effects of food production and water globalization on the environment and, conversely, of the effects of hydroclimatic variability on water and food security. To address this crucial point, we have set the following research questions: What are the global dynamics of water scarcity and how do these depend on the food trade? What drives the food trade and virtual water exchanges? How do local crises propagate into the global system? What are the future scenarios of food production, and how will this impact water resources? Are we heading toward a global water and food crisis? What actions should we take to delay or avoid the crisis?These compelling questions are intrinsically global as the international trade of massive amounts of food makes societies less reliant on locally available water, and entails large-scale transfers of virtual water (defined as the water needed to produce a given amount of a food commodity). The globalization of (virtual) water resources has impacts on short-term solutions to malnourishment, famine, and conflicts, but it also has relevant negative implications for human societies, as it contributes to reduce the resilience of countries to food and water shortage.Thus, as its primary scope, this research project aims at disentangling the dynamics of the global system of water use and trade, and determining the key drivers of the spatial and temporal variability of human reliance on freshwater resources, both at the producers and consumer scales. Such dependency games unavoidably modify the global patterns of water resources exploitation and stress. Therefore, a further primary scope of this research project is the understanding and detailing of those dependency phenomena for the determination of the impacts of any possible import-export crisis on food security and water use. Finally, within this project these global dynamics are set in the socio-economic frame which characterizes the globalization of water resources, thus accounting for market dynamics, demographic growth and policy implementation. Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far We have collected from public databases and validated billions of data concerning with food production, consumption and international trade (300 products, 30 years of coverage for trade and 60 years of coverage for production), with water use in agriculture, with global climatic and economic variables, etc. A set of advanced statistical and stochastic methods, hydrological and environmental-impact models, econometric and complex-network tools have been developed to cope with the challenge of understanding the intertwined water-food dynamics. We have published an open access database with nearly 9 million data on Water Footprint and Virtual Water Trade, by including time variability, adopting a country scale of analysis, and covering 357 primary and derived crops and animal products. We have made available producer-side and consumer-side water use efficiency, in order to cover the whole supply chain of any product. We have published 36 papers in top-ranked scientific journals and books, and researchers from our group have given 11 oral and poster presentations at international scientific conferences to present the project outcomes. Our dissemination efforts have involved more than 10.000 people in 10 national and international-scale events. We have shown that globalization of water is already a reality; that county’s population, economic power, and availability of agricultural land are the main drivers of the food trade; that the food stocks are not decreasing in time, as commonly believed, but they are subject to wide stochastic fluctuations; and we have shown that the vulnerability of the global system to the propagation of local crises has increased over time. We have organized educational projects in school (primary school, high school), including both teaching, education, and the preparation of materials and info-graphics. Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far) We have adopted an innovative, evidence- and data-based approach to address the ambitious research goals of the project. By joining forces of engineers, economists, and physicists, we contributed in placing the challenges of the water-food nexus in a quantitative framework. We have therefore contributed addressing relevant global challenges, including: to quantify the impact on fluvial systems of water withdrawals due to food production; to define the future scenarios of human use of water resources; to predict the future evolution of the food trade network; to understand the resistance and resilience of the future system to local and global crises.