Global Water Demand and Supply Projections

Abstract

This paper provides the results from the modeling framework presented by Cai and Rosegrant (2002), including projections of water demand and supply for domestic, industrial, livestock, and irrigation water use at the basin or country level in the global scope, during 1995 to 2025. Water demand is projected to grow rapidly for domestic and industrial uses, and relatively slowly for agriculture. The developing world is projected to have much higher growth in total water demand than the developed world, and about 93 percent of the additional demand will occur in developing countries. Moderate increases are projected for water supply capacity expansion, management improvement, and irrigation development. It is found that for the developing world, there will be increasing scarcity of water for irrigation, with a declining fraction of potential irrigation demand being met over time. Particularly large declines are found in dry basins that face rapid growth in domestic and industrial sectors. Variability in irrigation water supply due to climate variability tends to increase over time. Following presentation of the “best-estimate” baseline scenario, alternative scenarios are examined for changes in infrastructure investment, non-irrigation water demand growth, and groundwater pumping.