This paper considers whether there will be sufficient water available to grow enough food for a predicted global population of 9 billion in 2050, based on three population and GDP growth modelling scenarios. Under the a low population growth with high GDP growth scenario, global consumptive water demand is forecast to increase significantly to over 6,000 km3, which is approximately 3,000 km3 greater that consumptive use in the year 2000. Also of concern is that rising global temperatures are going to increase potential evaporation, and t us irrigation water demand, by up to 17%. Sustainable intensification of agriculture can provide solutions to this predicament. However, productivity growth i not fast enough and we face considerable risks in the next 20 to 30 years. Concerted action to combat food insecurity and water scarcity is required based on agricultural research and development, policy reform and greater water productivity, if the world is to feed its growing population.

Cities are complex and evolving systems with various factors playing key roles, e.g., population increase, the migration of population, the availability of resources, and the flexibility of policies. Consumers’ socioeconomic status is also an important aspect that needs to be studied in the context of a self-reliant urban city in its resource consumption. In this regard, the association between water–food and socio-economic attributes was analyzed based on the consumer-centric approach for the Hyderabad Metro Development Authority (HMDA) region, India. In this study, the embedded water content in food consumption was estimated and analyzed for nine food groups and twelve economic classes of the HMDA region. The middle economic classes were found to correspond to ~80% of embedded water content in the HMDA region, followed by the upper and lower economic classes. Except for cereals, per capita, the water consumption of all food groups increased with the spending power of the economic class. The green, blue, and grey consumption water footprints (WFs) suggested that much of the water that is being consumed in the HMDA region is precipitation-driven, followed by surface and groundwater resources. Limited water resources, water resource variability, climate change consequences including future climate projections, uncertainty in data, WF estimates, and region’s future growth imply a detailed study in drafting policies to become a self-reliant region.

In this review paper we focus on the dilemma of whether or not current fresh water supply will meet the demand/needs of agricultural crops despite the continuing impact of water scarcity. In addition, we evaluate whether an increase in future population, change in water demand and supply patterns, due to climate change, will allow sustainable food production. With increased scarcity of freshwater, new water conservation technologies and biotechnology were developed, as well as newly developed water sources such as recycled wastewater, and various water institutions, which may help ease water scarcity. With new advancements in farming practices and crop innovations global food supply is still challenged by climate change effects on both water and land resources used for food production.

Population growth, increasing demands for food, ever-growing competition for water, reduced supply reliability, climate change and climate uncertainty and droughts, decline in critical ecosystems services, competition for land use, changing regulatory environments, and less participatory water resources governance are contributing to increasing difficulties and challenges in water resource management for agriculture and food. The need for sustainable food security for our global population and the need for preserving the environment, namely natural and man-made ecosystems and landscapes, have created an increased need for integrated, participative and scalable solutions focusing the various levels of irrigation and nature water management, from the field crop to the catchment and basin scales. Meanwhile, challenges and issues relative to water management for agriculture and food have evolved enormously in the last 30 years and the role of active management of the components of the water cycle is assuming an increased importance since their dynamics are key to assure water use sustainability, mainly agriculture and natural ecosystems sustainability. However, different regions face context-specific challenges associated with water scarcity, climate, governance, and population requirements. The main and first challenge is producing enough food for a growing population, which is intimately related with challenges placed to agricultural water management, mainly irrigation management. This paper revises challenges and progress achieved in the last 30 years focusing on irrigated agriculture, mainly water management, and its contribution to food security and the welfare of rural communities.

Forecasts on population growth and economic development indicate that there will be substantial increases in food demand for the forthcoming decades. We focus here on the water requirements of food production, on the issue of whether there would be enough water to produce sufficient food in the future, and we offer options to face this challenge based on recent trends observed in some agricultural systems. Given the competition for water faced by the agricultural sector, and the uncertainties associated with climate change, improving the efficiency of water use in both rain-fed and irrigated systems is the main avenue to face the challenge. In rain-fed agriculture, managing the risk associated with rainfall variability is a promising option to increase productivity. In irrigated systems, a case study on the improvements in water productivity in Andalusia, Spain, is used to illustrate some of the opportunities to make progress. Progress in reducing irrigation water use in recent decades has been substantial, but decreasing the consumptive use of crops is a much more difficult challenge. The need for more research and technology transfer on improving water-limited crop production is highlighted, and emphasis is placed on interdisciplinary approaches to gain the insight needed to achieve new breakthroughs that would help in tackling this complex problem.

Quantifying the interactions of the food-energy-water (FEW) nexus is crucial to support new policies for the conjunctive management of the three resources. Currently, our understanding of FEW systems in metropolitan regions is limited. Here, we quantify and model FEW interactions in the metropolitan area of Phoenix, Arizona, using the Water Evaluation and Planning (WEAP) platform. In this region, the FEW nexus has changed over the last thirty years due to a dramatic population growth and a sharp decline of cultivated land. We first thoroughly test the ability of WEAP to simulate water allocation to the municipal, agricultural, industrial, power plant, and Indian sectors against historical (1985–2009) data. We then apply WEAP under possible future (2010–2069) scenarios of water and energy demand and supply, as well as food production. We find that, if the current decreasing trend of agricultural water demand continues in the future, groundwater use will diminish by ~23% and this would likely result in aquifer safe-yield and reduce the energy demand for water. If agricultural activities decrease at a lower rate or a multidecadal drought occurs, additional (from 7% to 33%) water from energy-intensive sources will be needed. This will compromise the ability to reach safe-yield and increase energy demand for water up to 15%. In contrast, increasing the fraction of energy produced by solar power plants will likely guarantee safe-yield and reduce energy demand of 2%. This last solution, based on an expanded renewable portfolio and current trends of municipal and agricultural water demand, is also projected to have the most sustainable impacts on the three resources. Our analytical approach to model FEW interconnectivities quantitatively supports stakeholder engagement and could be transferable to other metropolitan regions.

Water, energy, and food security are of critical concern as rising population growth and rapid urbanization place greater pressure on our natural resources. The trade of ‘virtual water’ through agricultural products and its appropriation through foreign direct investment (FDI) in food production have emerged as potential strategies for water-scarce countries seeking food security. In Saudi Arabia, where domestic agricultural enterprise remains a state priority despite extreme water scarcity, a shift to overseas food production to meet domestic demand could have significant implications for water and energy use as well as local labor markets. This study evaluates the growing internationalization of food production in water-scarce countries using the case of Saudi Arabia as a microcosm to illustrate the tradeoffs in resource consumption associated with crop selection and farming practices. This analysis indicates that the implications of different types of large-scale agribusiness must be more explicitly accounted for in government policy given the non-renewable nature of groundwater and energy. This work also quantifies the increase in the import of virtual water through conventional trade, which has significant potential to minimize groundwater pumping for food production in arid environments. A brief, complementary assessment of the growing role of FDI shows that further analysis is needed to ascertain the long-term resource impacts of direct investment in overseas enterprise and to minimize potentially negative impacts on water access and rural livelihoods in target nations. Active engagement of local communities and/or more holistic investment in infrastructure or improving agricultural productivity could also help avoid the potential for conflict and contribute towards long-term sustainability.

The unprecedented surge in urbanization and population growth rates is generating multiple impacts, affecting food, energy and water (FEW hereafter) demands. Moreover, the adverse effects are extending to climate, as well as to human and ecosystem health. Coordinated efforts are often deemed critical to minimize the trade-offs while maximizing the synergies in the use and the effective analysis of the interlinkages among food, energy, and water within urban ecosystems. Data are collected and transformed into useful information through different indicators, which are often applied to guide several policies in the urban domain. However, their different nature now asks for a critical reanalysis to collate them into different groups, understanding their guiding principles and identifying possible gaps for further policy- and design-oriented studies. This paper reviews the state-of-the-art on existing urban FEW nexus indicators. Indicators were found to belong to four main distinct groups, measuring resource fluxes (52%); quantifying environmental impacts (13%), and efficiency aspects (29%). Results highlight a need to develop new indicators, considering the inclusion of all involved factors within new integrated metrics. However, prior to developing an overall sustainability indicator system is presented, it would be vital to incorporate as many flows as possible to represent the entire urban systems.