International audience | Concerns about the water-energy-food (WEF) nexus have motivated many discussions regarding new approaches for managing water, energy and food resources. Despite the progress in recent years, there remain many challenges in scientific research on the WEF nexus, while implementation as a management tool is just beginning. The scientific challenges are primarily related to data, information and knowledge gaps in our understanding of the WEF inter-linkages. Our ability to untangle the WEF nexus is also limited by the lack of systematic tools that could address all the trade-offs involved in the nexus. Future research needs to strengthen the pool of information. It is also important to develop integrated software platforms and tools for systematic analysis of the WEF nexus. The experience made in integrated water resources management in the hydrological community, especially in the framework of Panta Rhei, is particularly well suited to take a lead in these advances.

Food, energy, and water are essential goods for human survival. The three goods are intrinsically connected through economic consumption and production linkages as well as ecological processes. All three are dependent on limited resources which are threatened by global drivers in the form of economic growth, population growth, and climate change that are particularly affecting developing countries. Therefore, a nexus perspective that simultaneously encompasses food, energy, and water has become crucial to avoid resource inefficiencies and to ensure the provision of the three goods for the most vulnerable people. This dissertation contributes to the research on the food-energy-water (FEW) nexus approach through first developing integrated modeling frameworks that capture the linkages between food, energy, and water, in order to secondly identify those policy measures that maximize the synergies for food, energy, and water security and minimize the tradeoffs. To this end, three studies analyze four policies – biofuels production, irrigation expansion, improved cookstoves and agroforestry – that directly affect food, energy, and water security and provide a large scope for realizing synergies. The empirical findings of this dissertation show that policy measures indeed produce some tradeoffs between FEW security, but that – if policies are designed correctly – the tradeoffs can be minimized while simultaneously maximizing the synergies. These findings are an essential contribution to the literature through proving that even in a world with enormous pressures on limited resources, prudent policy making can provide FEW security for all people. Finally, the results demonstrate that the development of integrated modeling frameworks is vital for quantitative analyses of policies that simultaneously affect the economic, social, and environmental spheres to identify the synergies and tradeoffs. This dissertation makes an important methodological contribution to integrated environmental-economic modeling of developing countries and may serve as a starting point for future research on linking the economy and the environment in models. | Nahrungsmittel, Energie und Wasser sind für den Menschen lebenswichtige Güter, die sowohl durch volkswirtschaftliche Produktions- und Konsumverflechtungen als auch durch Umweltprozesse intrinsisch miteinander verknüpft sind. Alle drei Güter sind auf begrenzte Ressourcen angewiesen, die durch globale Antriebsfaktoren wie Wirtschaftswachstum, Bevölkerungswachstum und Klimawandel stark gefährdet sind, welche besonders Entwicklungsländer beeinträchtigen. Eine Nexus-Perspektive, die Nahrungsmittel, Energie und Wasser gleichzeitig betrachtet, ist daher zentral, um ineffiziente Ressourcennutzung zu vermeiden und die Versorgung mit lebenswichtigen Gütern für besonders gefährdete Menschen sicherzustellen. Diese Dissertation zielt darauf ab, einen Beitrag zur Forschung über den Nahrungsmittel-Energie-Wasser (NEW) Nexus zu leisten, einerseits durch die Entwicklung von ganzheitlichen Simulationsmodellsystemen, welche die Verflechtungen zwischen Nahrungsmitteln, Energie und Wasser erfassen, um andererseits solche Politiken zu bestimmen, die sowohl die Synergien zwischen Ernährungs-, Energie- und Wassersicherheit maximieren als auch die Zielkonflikte minimieren. Dazu untersuchen drei Studien vier verschiedene Politiken – Biokraftstoffproduktion, Ausbau von Bewässerung, verbesserte Kochherde und Agroforstwirtschaft, – welche Ernährungs-, Energie- und Wassersicherheit direkt beeinflussen und daher zahlreiche Möglichkeiten für Synergien bieten. Die empirischen Forschungsergebnisse dieser Dissertation zeigen auf, dass Politiken fast immer gewisse Zielkonflikte zwischen Ernährungs-, Energie- und Wassersicherheit hervorbringen, aber dass – wenn Politiken richtig ausgestaltet sind – diese Zielkonflikte minimiert werden können und gleichzeitig Synergien maximiert werden. Diese Resultate bilden einen grundlegenden Beitrag zur empirischen Literatur, da sie belegen, dass sogar unter dem vorherrschenden gewaltigen Druck auf begrenzte Ressourcen eine kluge Politik die Versorgung mit Nahrungsmitteln, Energie und Wasser für alle Menschen erreichen kann. Außerdem manifestieren die Forschungsergebnisse die Notwendigkeit, ganzheitliche Simulationsmodellsysteme für die quantitative Analyse von Politiken zu entwickeln, die gleichzeitig volkswirtschaftliche, gesellschaftliche und ökologische Wirkungsbereiche beeinflussen, um Synergien und Zielkonflikte überhaupt zu identifizieren. Diese Dissertation strebt danach, einen wichtigen Beitrag zur ganzheitlichen ökologisch-ökonomischen Modellierung von Entwicklungsländern zu leisten, und kann als Ausgangspunkt für zukünftige Forschung über die Kopplung von volkswirtschaftlichen und ökologischen Modellen dienen.

The water footprint (WF), defined as the volume of water used per unit food produced, is becoming a popular indicator in a variety of assessments that relate food production to water use. The complexities underlying the phrase “water used” already point to the difficulties in computing an indicator with robust and general meaning. | Peer reviewed

Many modern cities have strongly invested in the sustainability of their urban water management system. Nordic cities like Stockholm or Copenhagen are amongst pioneers in investments towards integrated urban water management. However, cities can never be fully self-sufficient due to their dependency on external (water) resources. In this paper, we quantify this water dependency with respect to food consumption in nine cities located in the five Nordic countries (Sweden, Denmark, Finland, Norway and Iceland), by means of the water footprint concept. Detailed urban water footprint assessments are scarce in the literature. By analysing national nutrition surveys, we find that urban food intake behaviour differs from national food intake behaviour. In large Nordic cities people eat generally less potatoes, milk products (without cheese), meat and animal fats and they drink less coffee than outside city borders. On the other hand, they generally eat more vegetables and vegetable oils and they drink more tea and alcoholic beverages. This leads consistently – for the six large Nordic cities Stockholm, Malmö, Copenhagen, Helsinki, Oslo and Reykjavik – to slightly smaller food related urban water footprints (−2 to −6%) than national average values. We also analyse the water footprint for different diets based upon Nordic Nutrition Recommendations (NNR) for these cities. We assessed three healthy diet scenarios: 1) including meat (HEALTHY-MEAT), 2) pesco-vegetarian (HEALTHY-PESCO-VEG) and 3) vegetarian (HEALTHY-VEG). This shows that Nordic urban dwellers 1) eat too many animal products (red meat, milk and milk products) and sugar and drink too much alcohol and 2) they eat not enough vegetables, fruit and products from the group pulses, nuts and oilcrops. Their overall energy and protein intake is too high. A shift to a healthy diet with recommended energy and protein intake reduces the urban WF related to food consumption substantially. A shift to HEALTHY-MEAT results in a reduction of −9 to −24%, for HEALTHY-PESCO-VEG the reduction is −29 to −37%, for HEALTHY-VEG the reduction is −36 to −44%. In other words, Nordic urban dwellers can save a lot of water by shifting to a healthy diet.

Food and water security are directly linked through the agricultural sector and food production and processing. Increasing stresses on food and water resources, influenced by factors such as population growth and climate change, threaten global food and water security. Previous studies have attempted to address this issue with the development of various modeling frameworks, often combining food security and water security models to address the inter-relationship between the two concepts. This study first introduces some of the background and foundational principles behind food and water security models, then critically reviews models that jointly analyze the two concepts. Initially, the dynamic definitions and historic development of water and food security concepts are reviewed. Current global hydrological models and food production/consumption models are then discussed to provide requisite background on available modeling platforms that separately assess water and food security. This study then focuses on an evaluation of ten models that assess food and water security from an interdisciplinary perspective, providing in-depth analysis regarding input parameters, model processes, advantages and limitations. Results suggest that there is a need to further develop input datasets as well as spatial and temporal resolution in existing food and water security models. This will provide the foundation for the development of effective policies and strategies to mitigate future food and water security issues, while considering the protection of the natural environment.

Emerging interdisciplinary science efforts are providing new understanding of the interdependence of food, energy, and water (FEW) systems. These science advances, in turn, provide critical information for coordinated management to improve the affordability, reliability, and environmental sustainability of FEW systems. Here we describe the current state of the FEW nexus and approaches to managing resource conflicts through reducing demand and increasing supplies, storage, and transport. Despite significant advances within the past decade, there are still many challenges for the scientific community. Key challenges are the need for interdisciplinary science related to the FEW nexus; ground‐based monitoring and modeling at local‐to‐regional scales; incorporating human and institutional behavior in models; partnerships among universities, industry, and government to develop policy relevant data; and systems modeling to evaluate trade‐offs associated with FEW decisions.

Water, energy, and food are among the most important and fundamental resources for human beings and society. Despite the large potential for efficiency and reduction of losses, the demand for these resources is likely to increase due to population growth, changes in lifestyles, climate change, and other aspect of global change. The strong interconnectedness of these three vital resources has been termed the “Nexus” in the scientific literature in recent years. While many papers claim its fundamental importance, few provide specific ideas on how to deal with this Nexus in practice. This paper introduces twenty case-studies that are highlighted in this special issue that explore the practice of the Nexus and its scientific basis with particular focus on the Water-Energy-Food Nexus in the Asia-Pacific Region.

Recent research has documented shifts in per capita trophic interactions and food webs in response to changes in environmental moisture, from the top-down (consumers to plants), rather than solely bottom-up (plants to consumers). These responses may be predictable from effects of physiological, behavioral, and ecological traits on animal water balance, although predictions could be modified by energy or nutrient requirements, the risk of predation, population-level responses, and bottom-up effects. Relatively little work has explicitly explored food web effects of changes in animal water balance, despite the likelihood of widespread relevance, including during periodic droughts in mesic locations, where taxa may lack adaptations for water conservation. More research is needed, particularly in light of climate change and hydrological alteration.