As demands for water hit the limits of a finite supply, conflicts over water are spreading both within and between countries. Although outright "water wars" between nations are unlikely, mounting violence and hostility over water threatens social and political stability in many regions. Within countries, tensions are rising from worsening water stress in the downstream reaches of overtapped rivers, including China's Yellow River, Pakistan's Indus River, and Thailand's Chao Phraya. Between countries, the driving force behind water hostilities is the unilateral attempt-usually by a regional power-to construct a dam or other large development project in the absence of a treaty or other
mechanism that safeguards the interests of other nations in the river basin.

During the next decade, more than 50 countries on five continents could find themselves embroiled in water disputes unless they move quickly to strike agreements on how to share the rivers that flow across international boundaries. Wider use of conservation methods, stronger pricing and regulatory policies, and effective treaties and institutions
are needed to avert greater violence and conflict over water.

Facts and Figures

* Since 1950, the global renewable freshwater supply per person has fallen 58 percent as world population has swelled from 2.5 billion to 6 billion.

* By 2015, nearly 3 billion people-40 percent of the projected world population-are expected to live in countries that find it difficult or impossible to mobilize enough water to satisfy the food, industrial, and domestic needs of their citizens.

* Today Asia has approximately 60 percent of the world's people but only 36 percent of the world's renewable freshwater.

* Currently water-stressed countries in Asia, Africa, and the Middle East account for 26 percent of global grain imports. China, India, and Pakistan - all presently grain self-sufficient-will likely join the ranks of grain importers in the near future because of decreasing water availability per capita.

* On July 6, 2000, thousands of farmers in China's lower Yellow River basin clashed with police over a government plan to recapture runoff from a local reservoir.

* Two or more countries share some 261 of the world's rivers. These international watersheds account for about 60 percent of the world's freshwater supply and are home to about 40 percent of the world's people.

* An analysis of 1,831 international water-related disputes over the last 50 years reveals that two thirds of these encounters were of a cooperative nature while one fourth were hostile. On 37 recorded occasions, rival countries went beyond verbal antagonism and fired shots, blew up a dam, or undertook some other form of military action.

* The only recorded incident of an outright war over water was 4,500 years ago between two Mesopotamian city-states, Lagash and Umma, in the region we now call southern Iraq. Conversely, between the years 805 and
1984, countries signed more than 3,600 water-related treaties.

* Some 51 countries within 17 international river basins are at risk of water disputes over the next decade. Eight of these river basins are in Africa, primarily in the south, while six are in Asia, mostly in the southeast.

* China was just one of three countries that voted against a 1997 United Nations convention that established basic guidelines and principles for the use of international rivers.

* Since agriculture accounts for two-thirds of water use worldwide, and 80-90 percent in many developing countries, increasing the productivity of irrigation water is critical to averting conflict over water.

* Water treaties that provide for effective monitoring and enforcement are often remarkably resilient. The Indus Waters Treaty, signed by India and Pakistan in 1960, survived two wars between the signatories.