The Future of Fresh Water.

By 2025 at least 3.5 billion--about half the world's population--will live in areas without enough water for agriculture, industry, and human needs, according to a report released 21 October 2000 by the World Resources Insutute (WRI). Pilot Analysis of Global Ecosystems (PAGE): Freshwater Systems is one of a five-part series being prepared by the WRI to provide a comprehensive assessment of the state of the world's ecosystems. According to the report's authors, worldwide water quality conditions appear to have degraded in almost all regions with intensive agriculture and in large urban and industrial areas.

In developing countries over 90% of raw sewage is discharged directly into rivers and lakes without treatment. As a result, each year about 5 million people die from waterborne diseases such as cholera, and millions more are sickened, according to me report. In some respects, surface water quality in Europe and the United States has improved over the last two decades with advances such as better sewage treatment and reduced use of phosphorus in detergents. But other problems such as nitrate pollution from fertilizer runoff are increasing in these regions and worldwide. In addition to affecting human health, the degradation of the world's rivers, lakes, and groundwater has also caused an alarming decline in aquatic biodiversity. "People hear about the loss of species in the Amazon jungle, but the situation in the world's freshwater systems is much worse," says Carmen Revenga, one of the report's coauthors.

The primary goal of PAGE: Freshwater Systems is to show how sources of fresh water must be managed as systems, says Revenga. "Humans often divert water for a single purpose such as irrigation or power generation without looking at the ways those withdrawals affect the capacity of the system to continue to function and provide water and other goods and services in the future," she says. The authors believe the value of crucial freshwater services such as water purification and flood control is often ignored because such services are not traded like, for instance, agricultural products. "This makes it harder to assess the trade-offs at stake when different uses of a freshwater resource are proposed," they write.

"In general, [PAGE: Freshwater Systems] is an important contribution, a good status report," says Sandra Postel, director of the Global Water Policy Project in Amherst, Massachusetts, which promotes the protection and sustainable use of water. However, in preparing the report the authors often faced the problem of information that was incomplete or incompatible for extrapolation from one region to another. Says Revenga, "The amount of data on water is much scarcer in the 1990s than it was in the 1980s because many governments have reduced or stopped funding for water monitoring."

Highlighting such gaps in information is a major goal of the PAGE reports. The WRI states that the reports lay the groundwork for future efforts to collect more detailed and integrated information about world ecosystems. Findings from the report have already been used by the World Commission on Dams. PAGE: Freshwater Systems is available on the WRI Web site at http://www.wri.org/ wri/wr2000/. The WRI has also released PAGE reports on forests, grasslands, and agroecosystems, and has announced it will soon release a report on coastal ecosystems.