Food security is a high priority issue on the Chinese political agenda. China's food security is challenged by several anthropogenic, sociopolitical and policy factors, including: population growth; urbanization and industrialization; land use changes and water scarcity; income growth and nutritional transition; and turbulence in global energy and food markets. Sustained growth in agricultural productivity and stable relations with global food suppliers are the twin anchors of food security. Shortfalls in domestic food production can take their toll on international food markets. Turbulence in global energy markets can affect food prices and supply costs, affecting food security and poverty. Policy safeguards are needed to shield food supply against such forces. China must make unremitting policy responses to address the loss of its fertile land for true progress towards the goal of national food security, by investing in infrastructure such as irrigation, drainage, storage, transport, and agricultural research and institutional reforms such as tenure security and land market liberalization. The links between water and other development-related sectors such as population, energy, food, and environment, and the interactions among them require reckoning, as they together will determine future food security and poverty reduction in China. Climate change is creating a new level of uncertainty in water governance, requiring accelerated research to avoid water-related stresses.

The areas of energy, water and food policy have numerous interwoven concerns ranging from ensuring access to services, to environmental impacts to price volatility. These issues manifest in very different ways in each of the three “spheres”, but often the impacts are closely related. Identifying these interrelationships a priori is of great importance to help target synergies and avoid potential tensions. Systems thinking is required to address such a wide swath of possible topics. This paper briefly describes some of the linkages at a high-level of aggregation – primarily from a developing country perspective – and via case studies, to arrive at some promising directions for addressing the nexus. To that end, we also present the attributes of a modelling framework that specifically addresses the nexus, and can thus serve to inform more effective national policies and regulations. While environmental issues are normally the ‘cohesive principle’ from which the three areas are considered jointly, the enormous inequalities arising from a lack of access suggest that economic and security-related issues may be stronger motivators of change. Finally, consideration of the complex interactions will require new institutional capacity both in industrialised and developing countries.

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.

The Water-Energy-Food (WEF) nexus is a dynamic and complex system, in which the resources of water, energy, and food are inextricably linked. The system faces a number of threats including man-made hazards, e.g. overpopulation, urbanisation, ageing population, terrorism and geopolitical upheaval, and natural hazards such as climate change and extreme weather events. General indicators for the WEF nexus provide information on current access and availability of water, energy and food to a population. However, in industrialised nations such as the UK, such information is often masked by the consistently high access and availability of WEF resources. This paper proposes a composite WEF resilience index formed by aggregating two sets of indicators: one representing the availability level of WEF resources in terms of three WEF sectors; and the other representing population access to the resources at the household level. The WEF availability and the household accessibility indicators were calculated separately within the water, energy, food, and household sectors. Within each sector, an Analytical Hierarchical Process (AHP) was used for weighting sub-indicators based on experts’ evaluation of the relative importance among the sub-indicators. This allowed us to synthesize individual opinions using expertise level in a group decision-making framework. A pilot study was performed on the UK WEF nexus to measure resilience in recent times. This prototype composite index can be used for exploring the resilience of the WEF systems to shocks and changes in the presence of high WEF access and availability.

In the process of urban agglomeration, water-food security can be deemed as a key to support urban development and human living, but which can be challenged by expanded population growth, accelerated industrialization, unbalance regional economic development and diversity of weather (due to climate changes). In this study, a water resources allocation and food production (WF) optimization is developed for regional sustainability under multiple uncertainties. A hybrid two-stage fuzzy programming with Laplace criterion (TSFL) is proposed into a WF optimization to handle hybrid indeterminacies, which can increase the robustness of decision-making. The WF optimization with proposed TSFL method can be applied to a practical case of Beijing-Tianjin-Hebei (BTH) region. The obtained results associated with water deficits, optimal water allocations, inadequate capacities of food production, rational irrigation schedules, sound livestock scales, optimized agricultural possessing layouts and system benefits under various population-economy regulation scenarios can be obtained. The results can reflect the tradeoff between economic development and water-food safety; meanwhile, they can display risk violation of WF plan under various credibility levels and Laplace criterions (based on TSFL method). All above results can facilitate to produce an optimized water-food plan to support the synergetic development of BTH region in a robust manner.

Water, energy, and food resources are indispensable and irreplaceable resources for the survival and development of human society. This study systematically assessed the three resources system in Guangdong, Hong Kong, and Macao based on constructed direct and nexus-oriented, multi-regional input-output, and ecological network analysis models. Various network analysis (e.g., control, utility, hierarchy, and robustness) was adopted to identify the critical factors of inter-regional resources trade from a perspective of supply-demand. The results indicated that Guangdong, Hong Kong, and Macao have complex control linkages in the three resources trade network, and Guangdong is the key to improving the three resources network structure. The three resources network existed highly competition and exploitation in the three regions. Industrial development is unbalanced and competitive for the three resources. The wholeness water-energy-food trade network of the three regions stayed in a positive environment, but the positive effect level was relatively weak. The three resources network robustness in the three regions is at a medium level. Hong Kong and Macao's water-energy-food network systems have a high vulnerability, and the lowest system robustness was food-related energy in Hong Kong. Finally, we provide some measures to help the sustainable development of the water-energy-food resource system in the three regions, such as cross-regional coordinated management, integration industries development, seawater toilets-flushing, sea rice, and renewable energy.

This paper applies the system archetypes to investigate water, energy, food, and land nexus (WEFLN) in the Jatiluhur reservoir, the largest reservoir in Indonesia. The Jatiluhur reservoir has multiple functions such as hydropower supply and water supply for different end users. Multiple functions and multiple users mean there are tradeoffs in fulfilling the needs of different end users. Through feedback loops, the system dynamics tools concern on the interdependencies and the complexities of the nexus elements. It is found that growth engines such as industrial development and residential development support industrial and residential sectors. However, water availability will be a crucial issue as water supply can bound the growth engines. This situation is called the limits to growth archetype. Another system archetype named the success to successful is also identified. The success to successful archetype reminds us to distribute water and energy properly to sustain the growth in all sectors. Finally, outputs of this study can be a basis to develop a computer model and to support sustainable functions of the other reservoirs.

Irrigation in the Mediterranean region has been used for millennia and has greatly expanded with industrialization. Irrigation is critical for climate change adaptation, but it is also an important source of greenhouse gas emissions. This study analyzes the carbon (C) footprint of irrigation in Spain, covering the complete historical process of mechanization. A 21-fold total, 6-fold area-based, and 4-fold product-based increase in the carbon footprint was observed during the 20th century, despite an increase in water use efficiency. CH₄ emissions from waterbodies, which had not previously been considered in the C footprint of irrigation systems, dominated the emission budget during most of the analyzed period. Technologies to save water and tap new water resources greatly increased energy and infrastructure demand, while improvements in power generation efficiency had a limited influence on irrigation emissions. Electricity production from irrigation dams may contribute to climate change mitigation, but the amount produced in relation to that consumed in irrigation has greatly declined. High uncertainty in CH₄ emission estimates from waterbodies stresses a need for more spatially resolved data and an improved empirical knowledge of the links between water quality, water level fluctuations, and emissions at the regional scale.