Description:
Water is essential not only to survival but is also equally or even more important than nutrients in food production. Agriculture accounts for nearly 70% of the water consumption, with some estimates as high as 85% (Hanasaki et al., 2008a,b). Water scarcity will affect over 1.8 billion people by 2025 (WHO, 2007). This could have major impacts on health, particularly in rural areas, and thus also major impacts on farmer productivity. Although of great significance, such indirect effects are not considered here. Current projections suggest that water demand is likely to double by 2050 (Figure 20). Estimates project water withdrawals to increase by 22– 32% by 2025 (De Fraiture et al., 2003) and nearly double by 2050, for all SRES scenarios (Shen et al., 2008). For poor countries with rapid population growth and depletion of groundwater, water-deficit induced food insecurity is a growing problem (Rosegrant and Cai, 2002; Yang et al., 2003). One major factor beyond agricultural, industrial and urban consumption of water is the destruction of watersheds and natural water towers, such as forests in watersheds and wetlands, which also serve as flood buffers (UNEP, 2005).