This paper shows that water scarcity is a complex problem when it affects countries with a semi‐arid climate, ie countries for which there are fluctuations between a dry season and a season when rain occurs. The paper discusses the general vulnerability of the semi‐arid zone in terms of four different types of water scarcity, the effects of which are being superimposed on each other: two are natural (type A, arid climate, type B, intermittent drought years) and two are man‐induced (type C, desiccation of the landscape driven by land degradation, and type D, population‐driven water stress). When fuelled by a rapid population increase, a risk spiral develops, manifesting itself in social and economic collapse during intermittent drought years. The paper concludes that many countries in Africa are heading for severe water scarcity ‐in fact two‐thirds of the African population will live in severely water‐stressed countries within a few decades. This severe water stress will largely be the result of unfettered population growth.

Conventional approaches to food security are questionable due to their emphasis on food production and corresponding neglect of the huge amount of food losses and waste. We provide a comprehensive review on available information concerning China's food losses and waste. The results show that the food loss rate (FLR) of grains in the entire supply chain is 19.0% ± 5.8% in China, with the consumer segment having the single largest portion of food waste of 7.3% ± 4.8%. The total water footprint (WF) related to food losses and waste in China in 2010 was estimated to be 135 ± 60 billion m(3), equivalent to the WF of Canada. Such losses also imply that 26 ± 11 million hectares of land were used in vain, equivalent to the total arable land of Mexico. There is an urgent need for dialogue between actors in the supply chain, from farmer to the consumer, on strategies to reduce the high rates of food losses and waste and thereby make a more worthwhile use of scarce natural resources.

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Although high‐level attention has been drawn to the escalating world water problems, few changes are noticeable in terms of actual management of the water resource. Politicians continue to be misled by the apparent simplicity of water. The environment‐oriented community tends to focus only on problems arising from man‐induced side‐effects, and most people tend to take water for granted. The double challenge of providing adequate water supplies and meeting increasing food requirements of expanding populations, in addition to already existing water management problems, requires special attention. In addition, the intensifying pollution of water systems will have to be dealt with. Considerable human adaptation to physical realities as well as ingenious action are needed. There is a brief discussion of the risk of hydrocide, a condition of serious water‐quality degradation where available water is no longer sufficient, or cannot be used for the purposes needed. However, the main focus of the paper is on water quantity issues, highlighting the confusion arising from different methods of assessing water scarcity. Levels of regional water scarcity predicaments are discussed in terms of distinct regional clusters. Attention is drawn to the limitations of dry climate regions to achieve food self sufficiency, and the emerging need in many areas to import food; related trade and price aspects are also discussed. A distinction is made between efficiency of use and efficiency of allocation. The need for a global ethic regarding upstream–downstream water‐sharing is stressed, especially in cases of consumptive (evaporative) use of water for cultivating crops, which may deplete river flows available to downstream users. In conclusion, four key concerns are highlighted that call for global consensus.

The Okavango basin comprises the Cuito and Cubango active catchment areas in Angola, in addition to the Kavango-Okavango non-active catchment in northern Namibia and Botswana. The Okavango River water and its ecosystem resources are critically important sources of livelihoods for people in the basin. Pressures from livelihoods and development are already impacting on the environment. These pressures may increase in the future due to the rapid increase in population, the peace process and associated resettlement activities in Angola, and major development initiatives in Botswana and Namibia. For instance, possible future increase in water abstraction from the Okavango River may affect the long-term environmental sustainability of the Okavango Delta by minimizing channel shifting and thereby reducing spatial biodiversity. The paper argues that while conservation of the natural environment is critical, the pressing development needs must be recognized. The reduction of poverty within the basin should be addressed in order to alleviate adverse effects on the environment. The paper recommends that the development of sustainable tourism and community-based natural resource management initiatives may be appropriate strategies for reaching the Millennium Development Goals of poverty alleviation and achievement of environmental sustainability in the Okavango Basin. These initiatives have a comparative advantage in this area as demonstrated by the performance of the existing projects.