Growing thirstier by the day.

• Author: Kumar, Supriya
• Position: WORLD WATCHER - Global water scarcity

SOME 1,200,000,000 people--almost one-fifth of the world's population--five in areas of physical water scarcity, while another 1,600,000,000 face what can be called economic water shortage. The situation is expected to worsen as population growth, climate change, investment and management shortfalls, and inefficient use of existing resources restrict the amount of water available to people. It is estimated that, by 2025, 1,800,000,000 individuals will live in countries or regions with absolute water scarcity, with almost half of the world living in conditions of water stress.

Water scarcity has several definitions. Physical scarcity occurs when there is not enough water to meet demand. Its symptoms include severe environmental degradation, declining groundwater, and unequal water distribution. This scarcity occurs when there is a lack of investment and proper management to meet the demand of those who do not have the financial means to use existing water sources. The symptoms in this case normally include poor infrastructure. Large parts of Africa suffer from economic water scarcity.

World population is predicted to grow from 7,000,000,000 to 9,100,000,000 by 2050, putting a strain on water resources to meet increased food, energy, and industrial demands. Yet, there are many other pressures, including increased urbanization and overconsumption, lack of proper management and the threat of climate change. According to the United Nations Food and Agriculture Organization and UN Water, global water use has been growing at more than twice the rate of population increase in the last century.

At the global level, 70% of water withdrawals are for the agricultural sector; 11% are to meet municipal demands; and 19% are for industrial needs. These numbers, however, are distorted by the few countries that have very high water withdrawals, such as China, India, and the U.S.

Agricultural needs account for 44% of total water withdrawal among members of the Organisation for Economic Co-operation and Development, but this rises to more than 60% within the eight OECD countries that rely heavily on irrigated agriculture. In the four transitional economies of Brazil, Russia, India, and China, agriculture accounts for 74% of water withdrawals, but this ranges from 20% in Russia to 87% in India.

Policymakers must introduce a variety of measures to address global water scarcity. One important initiative is to support small-scale farmers. Much of the public...