KNOXVILLE, Tenn.– Assigning a monetary value to the world’s ecosystems and the services they provide sounds like an impossible task, but a group of scientists does just that in the May 15 issue of the journal Nature.
Dr. Robert Costanza of the University of Maryland and a team of economists and ecologists estimate that the dollars-and-cents value of nature exceeds that of the gross national product. Costanza’s study says the annual value of ecosystem services is an average of $33 trillion, 1.8 times the current GNP.
University of Tennessee ecologist and species extinction expert Dr. Stuart Pimm, writing the lead “News and Views” piece in the same issue of Nature, says these estimates have a value of their own. Hard numbers may persuade people to protect the environment when ethical and emotional considerations do not.
“What the environment does for us — and how we value it — is difficult to price. But the value is so huge that we must be aware of it as we make decisions for the future,” Pimm says in the article. “Many regions are losing money by converting assets into marketable commodities.”
The short sighted view has real economic implications, he notes. Draining wetlands may yield more land to grow soybeans, but destroy forever the ecosystem services the wetlands provide– services no one can afford to replicate.
Current prices assigned to such services do not accurately predict future value, Pimm says. “The price of an essential resource like water will rise non-linearly as it becomes scarce,” he says. “We already use half the global supply of fresh water.”
The study argues for responsible environmental decision-making based on both ecological and economic data, Pimm says.
“To ecologists, prices are woefully incomplete measures of nature’s value that poorly anticipate the consequences of humanity’s exponential growth,” Pimm says. “For economists, the challenge is how to assess an ecosystem’s non-market values and predict their future trends.”
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Contact: Dr. Stuart Pimm (423-974-1981)