Water security is a powerful concept that is still in its early days in the field of nutrition. Given the prevalence and severity of water issues and the many interconnections between water and nutrition, we argue that water security deserves attention commensurate with its importance to human nutrition and health. To this end, we first give a brief introduction to water insecurity and discuss its conceptualization in terms of availability, access, use, and stability. We then lay out the empirical grounding for its assessment. Parallels to the food-security literature are drawn throughout, both because the concepts are analogous and food security is familiar to the nutrition community. Specifically, we review the evolution of scales to measure water and food security and compare select characteristics. We then review the burgeoning evidence for the causes and consequences of water insecurity and conclude with 4 recommendations: 1) collect more water-insecurity data (i.e., on prevalence, causes, consequences, and intervention impacts); 2) collect better data on water insecurity (i.e., measure it concurrently with food security and other nutritional indicators, measure intrahousehold variation, and establish baseline indicators of both water and nutrition before interventions are implemented); 3) consider food and water issues jointly in policy and practice (e.g., establish linkages and possibilities for joint interventions, recognize the environmental footprint of nutritional guidelines, strengthen the nutrition sensitivity of water-management practices, and use experience-based scales for improving governance and regulation across food and water systems); and 4) make findings easily available so that they can be used by the media, community organizations, and other scientists for advocacy and in governance (e.g., tracking progress towards development goals and holding implementers accountable). As recognition of the importance of water security grows, we hope that so too will the prioritization of water in nutrition research, funding, and policy. © 2021 The Author(s) 2021. Published by Oxford University Press on behalf of the American Society for Nutrition.

A key challenge for sustainability is protecting water-related ecosystems and the services (WESs) they provide while enhancing food security. Food production usually drives land use change, which results in ecosystem services provision being altered. However, the underlying mechanisms are still unclear and relevant research is scarce. In this study, a spatio-temporal assessment framework was developed to assess the impact of food production-driven land use change on WESs and to analyze tradeoffs between food production and WESs provision, taking Songhua River Basin (SRB) as a case study. The results showed that: 1) food production increased from 0.497×108tons to 0.798×108tons despite area of cultivated land decreasing from 23.61×104km2 to 23.40×104km2 during the study period (2000–2015). 2) Water yield and soil retention both showed a downward trend, while nitrogen and phosphorus exports showed an increasing trend, in 2000–2015.3) Food production showed a trade-off relationship with soil retention and water yield, but a synergistic relationship with nitrogen and phosphorus export. This is important empirical evidence of the impact of food production-driven land use change on WESs. For simultaneous development of food production and WESs, a form of sustainable agricultural production must be established, with intensification of existing land use and establishment of farmland shelterbelts. This critical knowledge can be applied in developing practical ecosystem protection measures and land management strategies for food security in China and beyond.

A near-zero waste treatment system for food processing wastewater was developed and studied. The wastewater was treated using an anaerobic membrane bioreactor (AnMBR), polished using an outdoor photobioreactor for microalgae cultivation (three species were studied), and excess sludge was treated using hydrothermal carbonization. The study was conducted under arid climate conditions for one year (four seasons). The AnMBR reduced the total organic carbon by 97%, which was mostly recovered as methane (~57%) and hydrochar (~4%). Microalgal biomass productivity in the AnMBR effluent ranged from 0.25 to 0.8 g·L⁻¹·day⁻¹. Nitrogen (N) and phosphorous (P) uptake varied seasonally, from 18 to 45 mg·L⁻¹·day⁻¹ and up to 5 mg·L⁻¹·day⁻¹, respectively. N and P mass balance analysis demonstrated that the process was highly efficient in the recovery of nitrogen (~77%), and phosphorus (~91%). The performance of the microalgal culture changed among seasons because of climatic variation, as a result of variation in the wastewater chemistry, and possibly due to differences among the microalgal species. Effluent standards for irrigation use were met throughout the year and were achieved within two days in summer and 4.5 days in winter. Overall, the study demonstrated a near-zero waste discharge system capable of producing high-quality effluent, achieving nutrient and carbon recovery into microalgae biomass, and energy production as biogas and hydrochar.

The focus of this study is to show that by understanding the food-energy-water nexus, potential unforeseen negative outcomes can be avoided in the pursuit of sustainable development. To do this, this paper uses a novel approach to compare a combined farm and short rotation coppice willow system, in which the willow was planted as a riparian buffer, with a food-only and an energy only system. The impact of each system was investigated through the lens of the food-energy-water nexus using life cycle assessment techniques. Data from previous research was adapted in order to quantify the impacts for a typical Irish dairy farm, which is indicative of intensive agriculture across Europe. On a typical Irish dairy farm, the implementation of a short rotation coppice willow riparian buffer strip could reduce total nitrogen and phosphorus leachate by 14% and 9% respectively. Total CO₂eq emissions could be reduced by 16.5% if energy from the willow displaces fossil fuels, while the impact on milk production and profit is minimal. Thus, the use of short rotation coppice willow as a riparian buffer strip has the potential to reduce strain on the entire food-energy-water nexus. By considering the food-energy-water nexus, the negative impacts of the food-only and energy-only systems were also highlighted.The paper also shows how a better understanding of the food-energy-water nexus supports the United Nations Sustainable Development Goals and could help ameliorate the impact of climate change on the food-energy-water ecosystem.

The study explores complex non-linear decisions in land use allocation, focusing on the competition between cash and food crops. We develop an agent-based model to investigate whether the decision to opt for eucalyptus plantation is a rational choice in the perspective of different farmer types. We analyse the negative externalities (i.e. allelopathic effects) caused by the presence of eucalyptus on the productivity of neighbouring plots and the possible spill-over effects. The findings demonstrate that cultivation of eucalyptus as a cash crop may improve the rural populations' well-being only if there are no physical and economical constraints on access to food and services. The model shows that the allelopathic characteristics of eucalyptus strongly affect the soil fertility, inhibiting the possibility to switch to food crops in the future. In addition, the results of policy scenario simulations indicate that government environmental policies can play a key-role in improving awareness of the ecological effects of eucalyptus plantation on soil fertility in fragile socio-economic contexts characterized by high ecological vulnerability.

Demands for water, food, and energy are rising owing to increasing population and growing economy. Agriculture is the main source of food and is the largest consumer of water and has therefore the greatest impact on water security. It also greatly affects energy security and is also the main source of non-point source pollution. Changes in the availability of water, energy, and land are driven by uncertainties in nature and strongly affect food production, with severe implications for the security of water–food–energy nexus (WFEN). Thus, a coordinated and effective management of WFEN in the agricultural sector is needed. This paper therefore proposes an integrated modelling approach for the optimization of agricultural WFEN in a random environment. The approach quantifies the interactions and feedbacks within agricultural water, food and energy subsystems, making tradeoffs between agricultural benefit and environmental impacts, which will serve as sustainability indicators for agricultural systems, including crop farming and livestock farming. The incorporation of stochastic mathematical programming in the modeling framework aids in understanding how strategies and comprehensive benefits change under different scenarios. The approach was applied in a real-world case study in an irrigation district in northeast China. The development and implementation of such an integrated approach are anticipated to be applied in other agriculture-centered regions to guide policies of sustainable water, food, energy and land resources management.

Land, water, and energy resources are coming under unprecedented pressure owing to growing populations, urbanization, industrialization, and changing lifestyles, food habits, and climate. Generally, sectoral approaches are taken to address these challenges that overlook the close linkages between the water, energy and food sectors and resultant cross-sectoral implications. The result is an uncoordinated and unsustainable use of resources that increasingly threatens water, energy, and food securities in many parts of the world. To enhance sustainability in resource use, the use of water-energy-food nexus (WEF) approach has been advocated in recent years. Despite its conceptual appeals, the practical application of this approach in government planning and decision making has remained limited in part due to lack of an appropriate framework to operationalize the concept as a planning and decision-making tool. This paper suggests a framework for operationalizing the nexus concept in planning and decision-making, using South Asia as an example. The framework outlines four steps to evaluate and prioritize nexus issues to improve cross-sectoral planning and coordination using three broad criteria to assess the impact of actions in one sector on another: synergies (co-benefits), trade-offs (externalities), and neutrality. A cross-sectoral coordination body provides the institutional mechanism for ensuring coordination of policy and action. The four steps are: (a) harmonizing policy goals, (b) identifying interactions and critical connections between these sectors in an integrated manner, (c) assessing compatibility of nexus objectives and policy instruments, and (d) screening programs, projects, and investments against nexus goals. The framework is expected to help governments in coordinating the actions of diverse actors across the water, energy and food sectors and designing policies and programs that address trade-offs, while increasing production sustainably, conserving natural resources, and enhancing -water-energy-food nexus outcomes.

Through advancements in technology humans have cultivated more food, used more fossil fuel reserves, polluted the environment, and caused climate change. This was not the case some few decades ago where indigenous technologies were used in exploiting natural resources. Unfortunately, the effects of climate change on the planet are no more distant reality. The melting of glaciers, rising sea levels, extreme rainfall, and prolonged drought are already being experienced. These have affected water resources, land, and food security across the world. The limits of conventional climate change adaptation and mitigation strategies call for the integration of indigenous knowledge and technologies for tackling climate change issues. This is because of the importance that indigenous knowledge and technologies have for identifying the impacts and as well providing effective adaption and mitigation strategies to climate change. Thus, this chapter explores the potential of indigenous knowledge and technologies for the sustainable management of water, land, and food security amidst climate change. The applications of indigenous technologies and knowledge such as agroforestry, the use of sacred groves to conserve water, land, and biodiversity resources, and the practising of conservation-agriculture are discussed as solutions for reducing greenhouse gas emissions, water shortages, land degradation, and pollution. However, these indigenous technologies will be less useful in today's world if not harnessed. Thus also in this chapter, the scientific know-how available to improve the effectiveness of indigenous technologies for the sustainable use of water, land, and food resources have been identified (Robotics, sensors/detectors, internet of things) and discussed.

Food, energy, and water (FEW) are interconnected pillars that underpin the security of people’s livelihoods. In this paper, we propose a decision-support model to better understand and aid management of regional FEW nexus systems under uncertainty. We apply the model to a case study focusing on fluctuations in water supply, which significantly affect production in the agriculture and energy sectors in Shanxi Province, China. We use a two-stage, stochastic, chance-constrained programming approach to the proposed spatially detailed cost-minimizing FEW nexus model under demand and natural resource (land and water) constraints. This approach translates the target reliability level (i.e., the probability that the devised solution can satisfy all constraints) into a penalty that has to be paid in the case of their non-fulfillment. On this basis, robust decisions (i.e., production options suitable for a broad variation in certainty of water supply) are derived. Using this approach, we estimate the penalties required to achieve given levels of reliability by incentivizing the deployment of water-saving technologies. For example, our model predicts that water storage would become cost-effective if the penalty for exceeding the available water supply were 2.5 times higher than the current price for industrial water; this would enable at least 40% reliability compared to 18% if the penalty were at the current water price level. Taking advantage of the differences in water intensity of crops in different sites, our model optimizes the reservoir location, which allows water withdrawal by agriculture to be reduced by 1.23%. We also evaluate the benefits of incorporating uncertainty and missed opportunity due to a lack of perfect information. In the case study, we show that the benefits of including uncertainty in the form of the two-stage stochastic programming approach appear to be quite significant, reaching 4% of the total solution costs. Water-importing costs, taxes, and subsidies are instruments that translate into the penalty in this model; the modeling approach presented here can thus be used to inform cost-effective and robust management of the FEW nexus in Shanxi Province, China, and other water-scarce regions around the world.