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.

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.

Agriculture accounts for most of the renewable freshwater resource withdrawals in Malawi, yet food insecurity and water scarcity remain as major challenges. Despite Malawi’s vast water resources, climate change, coupled with increasing population and urbanisation are contributing to increasing water scarcity. Improving crop water productivity has been identified as a possible solution to water and food insecurity, by producing more food with less water, that is, to produce “more crop per drop”. This study evaluated crop water productivity from 2000 to 2013 by assessing crop evapotranspiration, crop production and agricultural gross domestic product (Ag GDP) contribution for Malawi. Improvements in crop water productivity were evidenced through improved crop production and productivity. These improvements were supported by increased irrigated area, along with improved agronomic practices. Crop water productivity increased by 33% overall from 2000 to 2013, resulting in an increase in maize production from 1.2 million metric tons to 3.6 million metric tons, translating to an average food surplus of 1.1 million metric tons. These developments have contributed to sustainable improved food and nutrition security in Malawi, which also avails more water for ecosystem functions and other competing economic sectors.

Agriculture accounts for most of the renewable freshwater resource withdrawals in Malawi, yet food insecurity and water scarcity remain as major challenges. Despite Malawi’s vast water resources, climate change, coupled with increasing population and urbanisation are contributing to increasing water scarcity. Improving crop water productivity has been identified as a possible solution to water and food insecurity, by producing more food with less water, that is, to produce “more crop per drop”. This study evaluated crop water productivity from 2000 to 2013 by assessing crop evapotranspiration, crop production and agricultural gross domestic product (Ag GDP) contribution for Malawi. Improvements in crop water productivity were evidenced through improved crop production and productivity. These improvements were supported by increased irrigated area, along with improved agronomic practices. Crop water productivity increased by 33% overall from 2000 to 2013, resulting in an increase in maize production from 1.2 million metric tons to 3.6 million metric tons, translating to an average food surplus of 1.1 million metric tons. These developments have contributed to sustainable improved food and nutrition security in Malawi, which also avails more water for ecosystem functions and other competing economic sectors.

Agriculture accounts for most of the renewable freshwater resource withdrawals in Malawi, yet food insecurity and water scarcity remain as major challenges. Despite Malawi’s vast water resources, climate change, coupled with increasing population and urbanisation are contributing to increasing water scarcity. Improving crop water productivity has been identified as a possible solution to water and food insecurity, by producing more food with less water, that is, to produce “more crop per drop”. This study evaluated crop water productivity from 2000 to 2013 by assessing crop evapotranspiration, crop production and agricultural gross domestic product (Ag GDP) contribution for Malawi. Improvements in crop water productivity were evidenced through improved crop production and productivity. These improvements were supported by increased irrigated area, along with improved agronomic practices. Crop water productivity increased by 33% overall from 2000 to 2013, resulting in an increase in maize production from 1.2 million metric tons to 3.6 million metric tons, translating to an average food surplus of 1.1 million metric tons. These developments have contributed to sustainable improved food and nutrition security in Malawi, which also avails more water for ecosystem functions and other competing economic sectors.

In this study, the water footprint (blue, green and grey WF) and virtual water theory were used to uniform measure the new challenges (population growth, population urbanization, dietary structure change, energy industry development, grain trade and climate change) of food security in Northwest China. Moreover, this study quantified the demand for new challenges to water resources from 2000 to 2016, and then evaluated their impact on water resources and food security in Northwest China. The results showed that in 2000–2016, population growth caused the food consumption WF to increase from 153.8 Gm³ to 159.6 Gm³, with an average annual growth rate of 0.4%. The ratio of per capita consumption of WF of urban residents to rural areas has increased from 80.3% to 120%. The per capita food consumption in the region increased by 1.3% annually due to changes in dietary structure. However, with the increase of water use efficiency, the WF decreased by 0.3% per year. Among them, the total consumption WF of food rations decreased by 51.9%, with an average annual decrease of 4.4%, and that of meat, dairy products and aquatic products increased by 2.4%, 10.8% and 3.0% per year, respectively. From the economic point of view, the development of the energy industry has increased the competition index of energy-grain to water resources from 0.22 to 0.49. Due to climate change, although the precipitation increased at a rate of 3.2 mm/yr, the increase in ET₀ was 3.3 mm/yr, and thus the demand for water resources in agricultural production increased. Based on the results, this paper suggests to carry out measures such as optimizes crop planting structure, adopts effective biological, agricultural technologies, guides healthy food consumption structure, strengthens international food trade and biofuel use and so on to reduce the WF of grain crops and energy industry. Ultimately, the goal of reducing regional water stress and ensuring food security is achieved.

The emerging and least developed countries are expected to absorb virtually all the increase in the world's population. With fast-growing population and ongoing urbanization, population density with reference to cultivated land is increasing significantly. In the emerging countries the increasing standard of living and to a certain extent biofuel production are adding more pressure on the already stressed land and water resources. Currently, most hungry people live in these countries and their number has been increasing for a few years. The least developed countries especially are regular food aid recipients. The future outlook is not promising: 80-90% of the required increase in food production will need to come from existing cultivated land. However, at present only 22% of the cultivated land in emerging and 11% in the least developed countries have irrigation facilities. Drainage development is almost non-existent. Better use of already cultivated land and water resources to ensure the required food production can be the key. The role of effective water management thus is crucial to achieve the objective of food security. This paper substantiates that the improvements in agricultural water management are closely linked to global food production.