|
Ecologists and economists have been debating for years about the economic value — if any — of wild species. In recent years, however, there has been growing recognition that natural landscapes, including the plants and animals they support, provide critical "ecosystem services" to human communities worth $33 trillion a year.
After Hurricane Katrina raged across the U.S. Gulf Coast in 2005, biologists contended that the damage was so severe because development had eliminated much of the Gulf of Mexico's natural coastal wetlands that normally would have absorbed some of the storm's fury. A recent study, moreover, catalogs the storm's unprecedented destruction of 320 million trees in the region. Similarly, scientists say coastal damage from a 2004 tsunami that killed more than 200,000 people in Southeast Asia was greatest along coastlines where mangrove swamps that once buffered storms have been replaced by shrimp farming ponds. Around the globe, the loss of natural biological diversity similarly may be eroding the benefits of nature that once were taken for granted, such as clean water and air, flood control, disease prevention and healthful foods.
"Ecosystem services are essential to human existence and operate on such a grand scale and in such intricate and little-explored ways, that most could not be replaced by technology," Stanford University ecologist Gretchen C. Daily wrote. "Yet, escalating impacts of human activities on natural ecosystems imperil their delivery."
In 2005, the Millennium Ecosystem Assessment study commissioned by the United Nations found that economic development around the world has begun to curtail the Earth's ability to provide for future generations. Drawing on the findings of nearly 1,400 experts, the project assessed 24 benefits that provide materials, regulate environmental conditions or enhance human spiritual and aesthetic values. It concluded that only four functions — farming, livestock grazing, fish farming and sequestering carbon dioxide — have improved in the last half-century. Fifteen are in decline. In addition, ecosystem damage has degraded nature's ability to purify water and air, control floods, prevent soil erosion and pollinate crops.
The assessment's board declared that a potential massive wave of species extinctions is "threatening our own well-being. The loss of services derived from ecosystems is a significant barrier to the achievement of (U.N.) goals to reduce poverty, hunger and disease."
The problem, Daily says, is that "until now there has been little incentive to measure or manage natural capital: It has been treated as essentially inexhaustible." A decade ago, a team of scientists came up with an estimate that ecosystems supply services worth $33 trillion a year to the global economy. In one effort that showed how natural services benefit even the largest cities, New York City saved $10 billion on a new water filtration plant by investing $1.5 billion in protecting its Catskill Mountains watershed against development. Costa Rica in 1996 began taxing fossil fuels to pay landowners to leave tropical forest intact, while an electric utility, water companies and a brewery now pick up the cost of protecting the watershed of Quito, Ecuador. The Chicago Climate Exchange now brokers carbon trades that reward landowners for maintaining forests and rangelands that absorb and store carbon dioxide from the atmosphere.
Economists, meanwhile, are trying to sort through how to define and measure ecological services and account for them in a "green" gross national product. "The benefits of nature are too important and too large to be 'left off the table' of national accounting," writes James Boyd, a senior fellow at Resources for the Future.
Some biologists and environmental groups caution that calculating ecological services can never replace conserving nature for its own sake. Indeed, they doubt financial markets will ever be capable of keeping up with technological change or protecting predators that kill people or livestock and other species. For example, scientists calculated that native bees provided $60,000 a year in pollination services to a Costa Rican coffee plantation. After coffee prices dipped, however, the owners shifted to growing pineapples that don't require pollination. "If we oversell the message that ecosystems are important because they provide services, we will have effectively sold out nature," wrote biologist Douglas J. McCauley, a Stanford graduate student.
But ecologists are now working on other methods to quantify the economic contributions of ecosystems and devise market-based mechanisms to conserve them. In 2006, Stanford teamed with The Nature Conservancy and World Wildlife Fund to undertake the Natural Capital Project, a 10-year venture to demonstrate how the value of ecological services can encourage conservation in such diverse habitats as China's Yangtze River Basin, Tanzania's mountain rain forests and California's Sierra Nevada Mountains.
Calculating the value of ecosystems, scientists hope, will encourage governments, industries and native communities to keep them intact. But the calculations will be arduous, and meanwhile development in many regions is accelerating.
"I worry that we're not going to have enough time," Daily says.
|
Read the Full Report (Subscription Required)
