Green and blue water accounting in the Limpopo and Nile basins: implications for food and agricultural policy

Water scarcity is a critical issue for food production in the poor developing countries because agriculture is the primary consumer of the dwindling freshwater around the globe. This paper calls for strategies for the sustainable use of water in agriculture. Most food in the world is produced using soil moisture from precipitation - known as &ldquo;green&rdquo; water. Irrigation is the source of &ldquo;blue&rdquo; water. <br /><br />This paper analyses alternative water futures using a combined green and blue water accounting framework embedded within the water simulation components of IFPRI&rsquo;s International Model for Policy Analysis of Agricultural Commodities and Trade (IMPACT). It uses a series of scenario results to 2050 for the Limpopo and Nile River Basins, which are representative of the wide range of irrigation and rainfed agricultural conditions.<br /><br />The paper presents the following policy recommendations:<br /> an accounting framework that distinguishes between green and blue water should be included in projections to enable enhanced analysis of alternative policies for improving agricultural production in the face of growing water scarcity. to identify policy options an examination of the relative contribution of precipitation to total water consumption and that by irrigated areas can be useful. alternative investments in agricultural productivity and irrigation expansion, can lead to major water savings from both irrigation and precipitation. In the Limpopo Basin, growing water scarcity suggests the need for investment in technologies aimed at enhancing irrigated and rainfed crop yields while in the Nile Basin, the focus needs to be on expanding irrigated areas and improving rainfed crop productivity. many existing technologies should be embedded into the support and extension systems to enable new research and development addressing rainfed crop water use to benefit the rural poor in developing countries. an integrated approach for the development of strategies aimed at helping humanity adapt to climate change and increased climate variability should be adopted. The authors conclude that an approach that combines blue- and green-targeted water management strategies with other complementary rural agricultural development investments, has the potential to positively impact the lives of many poor people.