This winter's disastrous mudslides in Washington and Oregon were partly traceable to overharvesting of timber, which disrupted the natural flood controls that forests exercise over flows of water, Stanford ecologist Paul Ehrlich said during a Symposium on "Ecosystem Services" held Sunday, Feb. 16, at the annual meeting of the American Association for the Advancement of Science.
The mudslides are a reminder that ecosystem services - the "utilities" that natural systems provide free of charge, like pollination of crops and maintenance of soil fertility - can be lost at great cost to local and global economies. "The loss of nature's services is not some hypothetical future disaster, or something restricted to poverty-stricken regions of the world," Ehrlich said.
"Interference with nature's services comes home to the rich in higher fish prices and loss of sport fisheries; loss of real estate values; higher risks from 'natural disasters' like floods, droughts and possibly other extreme weather events," he said.
When ecosystems are disrupted, affluent North Americans suffer outbreaks of agricultural pests; diseases such as Lyme disease and giardia; acidification and decline of precious forests; and rapid siltation of reservoirs, threatening the sustainability of irrigation and power generation.
"Expansion of the human enterprise is seriously damaging the natural systems that provide the services that underpin our economic security," Ehrlich said. The damage is a product of population growth, increased consumption of resources per person, and the cultural, institutional and technical means through which each unit of consumption is supplied. "Yet a flood of lies and misinformation is being generated by anti-environmental forces that helps keep that fact from decision makers and from the general public," he said.
BrownlashEhrlich coined the term "brownlash" to describe the efforts of those trying to confuse the public about the findings of environmental science. Brownlashers (whose ideas are a backlash against the "green" findings of the scientific community) make a wide variety of claims that he calls "preposterous." These include assertions that the ozone hole is a hoax, that concern about global warming is unwarranted, that there is no extinction crisis and, most outlandish of all, that continued human population growth can be supported for 7 billion years. "Those claims are diametrically opposed to the scientific consensus,"he said.
"Those generating the brownlash are willing to risk nature's crucial services to continue on a business-as-usual course - a course that may be congenial to their personal financial interests. Nature's services are supplied free of charge by ecosystems, in which biodiversity - populations of plants, animals and microbes - are vital working parts. The trees, shrubs and herbs growing on a Washington State hillside, for example, not only help to control erosion and flooding, but they also are involved in maintaining the balance of gases in the atmosphere, cleaning the air and recycling wastes.
"That's why scientists are so concerned with the mass extinction of populations and species now under way," Ehrlich said. "A balance between human activities and safeguards for the natural systems that provide economic prosperity is essential to human health, happiness and survival."
Humanity is causing widespread losses of biodiversity through destruction and alteration of habitats, transporting organisms to new locations, and overharvesting living resources such as fishes, Ehrlich said. "Loss of biodiversity is the most irreversible of the kinds of damage Homo sapiens is inflicting on its environment."
Releasing enormous quantities of toxic substances, failing to conserve soils, overexploiting non-living resources such as groundwater, and modifying large-scale biophysical processes (especially altering climates, thinning the ozone shield and disrupting biogeochemical cycles) also add greatly to the assault that Homo sapiens is mounting on its own life-support systems, he said. He pointed out that humanity causes the extinction of at least one species and thousands of populations of other organisms every day. At the same time humans are using up goods that crippled ecosystems will be unable to replenish, for example by causing the annual loss of some 25 billion tons of soil, and overpumping the southern part of the Ogallala aquifer at roughly 100 times its recharge rate.
"We are busily sawing off the limb on which we are perched - yet that is never mentioned in the brownlash literature that attempts to persuade people that environmental problems are relatively minor or nonexistent," Ehrlich said.
Economic losses in the trillions"The scientific community has just released a comprehensive evaluation of our life support systems in a book, Nature's Services, edited by Gretchen Daily," he said. "It documents their economic value to humanity, showing that ecosystem services are worth trillions of dollars annually.
"This was a critically important effort, " Ehrlich noted, "because it will encourage decision makers to incorporate that value into policy-making. "For instance, the Forest Service should include the costs of floods and mudslides in their calculations of fees for timber harvesting.
"But the dollar value clearly only sets a lower bound on the worth of the services. The value of our ability to feed ourselves or to avoid catastrophic floods cannot be fully expressed in monetary terms. What is the true cost of hundreds of millions of lives cut short or lived in utter misery?
"Although many scientific uncertainties remain," Ehrlich continued, "more than enough is known to allow humanity to start developing and implementing steps to sustain its life-support systems and thus preserve civilization.
Ehrlich outlined measures that would help preserve those systems by reducing the scale of human activities:
- Foster the social and economic conditions that will bring an end to population growth "as quickly as is humanely possible" and begin a slow decline in human numbers.
- Make U.S. consumption sustainable, since we're the most overconsuming society, and the most culturally influential. "We must set an example for the rich, and simultaneously help the poor find ways to increase necessary consumption."
- Wherever possible, develop and deploy more efficient, less environmentally damaging technologies.
"To provide a reasonable chance of averting disaster, much more effort will be required of natural and social scientists to find paths to sustainability," Ehrlich concluded. "Scientists must also put more effort into countering the brownlash. It now threatens seriously to retard progress toward protecting nature's services and thus menaces our grandchildren and the future of our species."
REPORTERS NOTE: Paul Ehrlich will also participate in an AAAS session titled "Biodiversity and Human Responsibility" on Tuesday, Feb. 18. from 8:30 to 11:30 a.m. at the Washington State Convention Center in Seattle. His topic for that session is "Ameliorating the Human Impact on Global Ecosystems and Biodiversity."