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.

Water is a factor input for many food system activities such as agriculture, food processing and consumption. However, food system activities also affect water resources. Moreover, the shift in focus of food security in Low- and Middle-Income Countries (LMICs) from producing enough staple foods toward healthy diets stimulates local production of fresh food such as fruit, vegetables and fish even in water scarce regions. To secure local production, polluted water is used for food production, processing and consumption, which might jeopardize human health. However, scientific evidence is still scattered and fragmented. The aim of this study is to systematically investigate the empirical tested impacts of water quality on the food system activities and vice versa. Using a comprehensive framework, we sketch the inter-relationships between water quality and food systems based on a literature study. Food system activities included food production (crop production, livestock and aquaculture), food processing, and food consumption. Multiple contaminants were incorporated such as nitrogen, phosphorus, pesticides, pathogens, cyanotoxins, and heavy metals. Moreover, we considered different water sources such as groundwater, surface water, wastewater and coastal water. We found that food system activities contaminate water in several ways, and these differ between food system activity and type of food produced. The impact of water quality on the food system depends on the food produced, the type of contaminant and techniques of food preparation. In addition, food is contaminated in multiple ways along the food system. Irrigation with polluted water may sound familiar, but polluted water is sometimes also used in food processing (cleaning of equipment or food products), and in food preparation (at home or by street vendors). Hygiene in food consumption is crucial to prevent fecal-oral transmission. However, water, sanitation and hygiene (WASH) received little attention in relation to food consumption. If local production of fresh food is encouraged to improve food security, all aspects of water quality should be analyzed to avoid undesirable consequences.

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.

N-nitrosamines are potent carcinogens, particularly N-nitrosodimethylamine (NDMA) and N-nitrosodiethylamine (NDEA), which are commonly found in a variety of foods and drinking water. We calculated the food and drinking water intakes of NDMA, NDEA, and total volatile nitrosamines (TVNA) by Chinese residents in different provinces by multiplying the reported total diet study results by the nitrosamine contents in food and drinking water. The weighted content of nitrosamines in each category of foods and the concentration of nitrosamines in drinking water was obtained through literature review. The exogenous NDMA, NDEA and TVNA intakes of adult residents in 20 provinces ranged from 171 to 425 ng/d, 41 to 140 ng/d and 373 to 1028 ng/d, respectively. The main contributors to NDMA and TVNA intakes were vegetables, cereals, aquatic products, and meats while the main sources of NDEA intake were vegetables and cereals. The average total NDMA intake per capita in China (251 ng/d) was similar to that in Germany in 1991 (231 ng/d) but higher than that in the United States (136 ng/d), Canada (87.6 ng/d) and France (188 ng/d). Large differences in nitrosamine intakes were observed between the coastal provinces and inland provinces. Drinking water was estimated to contribute 13.1%, 1.3% and 10.8% of the exogenous intakes of NDMA, NDEA and TVNA, respectively. Based on our results, we recommend setting the NDMA drinking water criterion of 40 ng/L. Overall, this study presents basic information regarding nitrosamines intake via food and drinking water in China that will facilitate risk assessment, generation of health advisories and policy making.

South Asia is energy-poor, water-stressed, and food-deficient, and these problems are expected to intensify with high population growth, rapid economic growth and industrialization, urbanization, and changing climate. Although the water, energy, and food security challenges are interconnected, they are dealt with in isolation, which fails to address the challenge of trade-offs and exacerbates the problems. The increased resource scarcity underlines the need for integrated solutions which ensure optimal resource use and maximize benefits. This article uses a nexus perspective to explore possible integrated solutions that support multiple uses of water at different scales and times. The analysis shows that the potential of water resources is underdeveloped and synergies between water, energy, and food are not fully harnessed. With proper coordination and management, water resources can generate multiple benefits for both upstream and downstream areas, including regional public goods such as regional connectivity and flood and drought management.

Water, food, energy, climate change and land subsystems are closely intertwined, and play remarkable roles in regional resources management system. Quantification of connections, synergies, and tradeoffs across these subsystems is needed in a more integrated and comprehensive manner, which is challenging due to the complexities and uncertainties involved therein. This paper proposed an inexact optimization approach from a novel water-food-energy-climate change-land (WORLD) nexus perspective, which has potential to promote social-economic development, guarantee livelihood security, and achieve low-carbon target. The approach is capable of (1) helping decision makers identify optimal policy alternatives among water, land, and energy, balancing economic benefit, water supply guarantee rate, hydroelectric generation, water-land utilization, crop yield, and greenhouse gas emission, via a multi-objective non-linear optimization model; (2) providing decision makers insights into in-depth analysis of optimal water-land resources allocation strategies associated with different levels of water supply, optimistic-pessimistic attitude, and climate change and where the effort could be made towards regional sustainability; (3) dealing with fuzzy uncertainties simultaneously occurring in objective functions and constraints as well as tracking fluctuating attitudes of decision-makers. The effectiveness of proposed model was verified in a real-world case in Zhanghe Irrigation District, Hubei Province, China. The changing range of economic benefit, crop yield, energy production, and environmental impacts were obtained based on optimal water-land resources allocation under different confidence levels and risk attitudes. Results under climate change scenarios show that climate change exacerbated local water shortage, especially in RCP 8.5, which requires 4.24 × 10⁸ m³ of compensatory external water. Results also show that CO₂ emission contributed 94.9% of GHGs emission, while fertilizers application contributed to 58% of total CO₂ emission amount, calling for effective fertilizer utilization management. Compared with single objective models, proposed model performs better on providing coordinated policy solutions. The proposed approach can help manage resources in WORLD nexus system in a sustainable way, and is portable to other similar regions to promote sustainable development.

peer reviewed

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.

Global agricultural production is expected to double by 2050 due to both global population increase and changes in diets as a consequence of growing incomes. This also means more pressure on water resources, as agriculture accounts for 70 % of global water withdrawal and for energy production as the entire food supply chain accounts for about 30 % of total global energy consumption. Although there are ongoing discussions related to the sustainability of food, water, and energy sectors, integrating these sectors is still rare and challenging. We investigated the effects of agricultural practices on the Food, Water and Energy (F-W-E) nexus security systems by evaluating the results reported in scientific literature. Focusing on the Brazilian Atlantic Forest biome as a study case, our main goals were 1) to elucidate the impacts of rural conservation practices on food, water, and energy production based on literature analysis, 2) to propose F-W-E attributes and evaluate how they are addressed by rural practices. Our findings demonstrated, in general, a positive impact of agricultural conservation practices on F-W-E security attributes. Indeed, 76 % of the combination between a conservational practice with a F-W-E attribute was positive. Some agricultural practices, such as no tillage are very well documented (45 % of all combinations), especially regarding their effects on soil quality parameters. We found few results connecting agricultural practice and energy aspects. These results are key elements that corroborate with the agriculture multifunctionality approach, and the results can better guide the planning of strategies in the agricultural sector and subsidize decision making.

The COVID-19 pandemic offers an opportunity to examine the impacts of system-wide crises on key supply sectors such as water, energy and food. These sectors are becoming increasingly interlinked in environmental policy-making and with regard to achieving supply security. There is a pressing need for a systematization of impacts and responses beyond individual disruptions. This paper provides a holistic assessment of the implications of COVID-19 on the water–energy–food (WEF) nexus. First, it integrates the academic literature related to single cases and disruptions to provide a broader view of COVID-19 demand- and supply-side disruptions and immediate effects. Then, the major, long-term impact categories of medicalization/hygienization, (re)localization of production, and demand fluctuations are highlighted. These impacts result in priority cross-links such as irrigation, energy requirements for local food production, energy use for water and wastewater treatment, or water for energy use. Finally, sector-level insights on impacts and responses are provided, drawing from illustrative cases. The analysis of impacts of COVID-19 on the WEF nexus reflects heterogeneous experiences of short-term adaptations, and highlights the revaluation of the water–food–trade nexus. Revived debates on food sufficiency can benefit from green applications to minimize expected trade-offs. The current crisis also reveals some gaps in the WEF nexus debates with regard to the lack of risk-based perspectives and the need for a better consideration of spatial aspects in resource integration. Regarding resource-security issues in the WEF nexus, the COVID-19 stress test boosts debates concerning the adequacy of the production value chains (e.g., contingency and storage, diversification, and self-sufficiency) and the value of cross-border integration (e.g., trade, globalization, and aid).