Although nutritionists have long been aware of the importance of clean drinking water and sanitation, water is becoming part of the international political agenda only after a slow realization of its scarcity. This is mainly because water has been taken for granted in industrialized countries except during periods of drought. in many areas of developing countries, water shortages already exist. Even with improved management, new sources of water will have to be developed at higher costs per project. Provision of clean water and sanitation has been rendered difficult by rapid urbanization since the middle of the twentieth century. Although cities have managed to provide a water supply, they have not been able to provide sewage and wastewater treatment. Meanwhile, irrigated agriculture uses nearly 70% of world water. in the future, food security will become even more dependent on irrigation. Poor management, due mostly to low salaries and political interference, is one of the main reasons for inefficient water systems. Underpricing of water in towns and on farms discourages conservation. Furthermore, people who do not have access to tap water in developing countries pay 10 times more than those who have taps.

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.

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.

Present water shortage is one of the primary world issues, and according to climate change projections, it will be more critical in the future. Since water availability and accessibility are the most significant constraining factors for crop production, addressing this issue is indispensable for areas affected by water scarcity. Current and future issues related to “water scarcity” are reviewed in this paper so as to highlight the necessity of a more sustainable approach to water resource management. As a consequence of increasing water scarcity and drought, resulting from climate change, considerable water use for irrigation is expected to occur in the context of tough competition between agribusiness and other sectors of the economy. In addition, the estimated increment of the global population growth rate points out the inevitable increase of food demand in the future, with an immediate impact on farming water use. Since a noteworthy relationship exists between the water possessions of a country and the capacity for food production, assessing the irrigation needs is indispensable for water resource planning in order to meet food needs and avoid excessive water consumption.

In the developing world’s irrigated areas, water management and planning is often motivated by the need for lasting food security. Two important policy measures to address this need are improving the flexibility of water appropriation rules and developing irrigation storage infrastructure. Little research to date has investigated the performance of these two policy measures in a single analysis while maintaining a basin wide water balance. This paper examines impacts of storage capacity and water appropriation rules on total economic welfare in irrigated agriculture, while maintaining a water balance. The application is to a river basin in northern Afghanistan. A constrained optimization framework is developed to examine economic consequences on food security and farm income resulting from each policy measure. Results show that significant improvements in both policy aims can be achieved through expanding existing storage capacity to capture up to 150 percent of long-term average annual water supplies when added capacity is combined with either a proportional sharing of water shortages or unrestricted water trading. An important contribution of the paper is to show how the benefits of storage and a changed water appropriation system operate under a variable climate. Results show that the hardship of droughts can be substantially lessened, with the largest rewards taking place in the most difficult periods. Findings provide a comprehensive framework for addressing future water scarcity, rural livelihoods, and food security in the developing world’s irrigated regions.

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.

Relying on published literature, we reviewed water-energy-food issues in Lao PDR in the context of a policy shift to more sustainable ‘green growth’ and significantly increased infrastructure investment resulting from China’s Belt and Road Initiative. The BRI provides the prospect for the country to address its infrastructure deficit and transform from a ‘land-locked’ to a ‘land-linked’ country. However, great care is needed to ensure that future investments do not result in further environmental degradation and harm to communities. An integrated ‘nexus’ approach, in which enhanced water management is central, is a prerequisite for more inclusive and sustainable development.

PR | IFPRI4; CRP2 | EPTD; PIM | CGIAR Research Program on Policies, Institutions, and Markets (PIM)