Water is essential for growing food; for household water uses, including drinking, cooking and sanitation; as a critical input into industry; for tourism and cultural purposes; and for its role in sustaining the earth's ecosystems. But this essential resource is under threat. Growing national, regional, and seasonal water scarcities in much of the world pose severe challenges for national governments and international development and environmental communities. The challenges of growing water scarcity are heightened by the increasing costs of developing new water, degradation of soil in irrigated areas, depletion of groundwater, water pollution and degradation of water-related ecosystems, and wasteful use of already developed water supplies, often encouraged by the subsidies and distorted incentives that influence water use.
Water development is critical for food security in many regions of the world. Today's 250 million hectares of irrigated area, worldwide, is nearly five times the amount that existed at the beginning of the twentieth century. Without irrigation, increases in agricultural yields and outputs that have fed the world's growing population would not have been possible. Further, irrigation has stabilised food production and prices by enabling greater production control and scope for crop diversification. Thus, irrigation has been vital to food security and sustainable livelihoods, especially in developing countries during the Green Revolution, through increased income and improved health and nutrition, locally, and by bridging the gap between production and demand, nationally.
Continued rapid growth of domestic and industrial water uses, growing recognition of environmental demands for water, and the high cost of developing new water resources threaten the availability of irrigation water to meet growing food demands. A crucial and urgent question for the world, therefore, is whether water availability for irrigation — together with feasible production growth in rainfed areas — will provide food to meet growing demand and ultimately improve national and global food security. This book attempts to answer this question by addressing the relationship between water availability and food production including the following key issues:
- How will water availability and demand evolve over the next three decades, accounting for availability and variability in water resources, water supply infrastructure and irrigation and nonagricultural water demands?
- How will water scarcity affect food production and the availability of water for environmental purposes?
- How much of future food production will come from rainfed and irrigated areas?
- What are the impacts of alternative water policies and investments on water supply and demand, food production and demand, and food security?
