As the sea has shrunk to scarcely half its original size, the rising salt concentration has destroyed all fish, eliminating a rich fishery that once landed 100 million pounds of fish a year. Similarly, the Colorado, the major river in the southwestern United States, rarely ever makes it to the Gulf of California, and the fishery at its mouth has disappeared. The link between food shortages and water shortages is close. Hydrologists estimate that when the amount of fresh water per person in a country drops below 1,700 cubic meters per year the country is facing water stress. Postel estimates that the number of people living in countries experiencing water stress will increase from 467 million in 1995 to over 3 billion by 2025 as population continues to grow.
Water scarcity leads inevitably to competition between urban and rural residents.
Since it takes 1,000 tons of water to produce 1 ton of grain, it's cheaper for a country to divert water to its urban centers and import grain than to have its own farmers use the limited water to grow food. This works fine until a country runs out of money or there's a crash in the world grain market. With more and more countries looking to the world market for food, spreading water scarcity may translate into world food scarcity sooner rather than later. Related Sites Pillar of Sand is available through the Worldwatch Institute. The mission of the International Water Management Institute is to contribute to food security by better management of water resources.