Along with the social, cultural, and moral arguments for conserving nature, here's one more reason to keep wild areas wild: cold, hard cash. A study in the 9 August 2002 issue of Science, published by the American Association for the Advancement of Science suggests that "a single year's habitat conversion costs the human enterprise, in net terms, on the order of $250 billion that year, and every year into the future."

Although habitat destruction continues unabated throughout the world, mounting evidence suggests that this trend is a bad economic bargain. From tropical forests to ocean reef systems, roughly one-half of an ecosystem's total economic value is lost when that ecosystem is converted from its wild state to human use, according to the Science study.

The Science team estimates that a network of global nature reserves would ensure the delivery of goods and services worth annually at least $4400 billion more than goods and services from their converted counterparts, making the benefit to cost ratio more than 100 to 1 in favor of conservation.

"The economics are absolutely stark. We thought that the numbers would favor conservation, but not by this much," says lead author Andrew Balmford of the University of Cambridge, U.K.

Balmford and colleagues compared the difference in the value of economic benefits provided by relatively intact ecosystems and by converted versions of those ecosystems. Although they reviewed more than 300 case studies of such conversion, they only identified five examples that met their rigorous standards for comparing benefits.

The economic value of an ecosystem can be measured in terms of the "goods and services"--including climate regulation, water filtration, soil formation, and sustainably harvested plants and animals--that the ecos
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Contact: Lisa Onaga
lonaga@aaas.org
202-326-7088
American Association for the Advancement of Science
8-Aug-2002