[Paleopsych] NYT: How Much Is Nature Worth? For You, $33 Trillion
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Thu Jul 7 14:47:47 UTC 2005
How Much Is Nature Worth? For You, $33 Trillion
The New York Times, 97.5.20
[Note the date. I found this when doing some Spring cleaning. No,
I won't say which spring!]
By WILLIAM K. STEVENS
HOW much is nature worth?
Some say the question is unanswerable, that it is impossible to
calculate a dollar value for the natural world. Others say the question
should not even be asked; that nature, like human life, is priceless and
should not be devalued as if it were a mere commodity.
But economists and ecologists are searching for the answer anyway.
Nature performs valuable, practical, measurable functions, they say;
without them the human economy could not exist, and in many cases people
could not duplicate them as cheaply -- or at all. And they say it is time
that the value of these functions is considered when economic decisions
One notable example of nature's economic value that they cite is the
purification of New York City's water supply by microorganisms as the
water percolates through the soil of the Catskills. The city plans to
spend $660 million to preserve that watershed in good health; the
alternative, a water treatment plant, would have cost $4 billion to build.
Nature performs a long list of other economic services as well. Flood
control, soil formation, pollination, food and timber production,
provision of the raw material for new medicines, recreational
opportunities and the maintenance of a favorable climate are among them.
But like a well that is taken for granted until it runs dry, these
ecosystem services, as ecologists call them, have long been overlooked
until they either no longer work or are gone -- as, for instance, when the
widespread destruction of Midwestern wetlands meant they could no longer
perform their natural function of sponging up water from disastrous floods
like those of recent years.
And to the extent ecosystem services are noticed at all, people have
tended to regard them as free.
Now, as human activity gradually uses up or destroys this natural
capital and eats away at the natural systems that provide many of the
services, many experts are insisting that the worth of ecosystem services
must be calculated and heeded.
The results of the latest and in some ways the most ambitious effort to
place a dollar value on natural capital and services were announced last
Thirteen ecologists, economists and geographers, in a report in the
journal Nature, estimated the present global value of 17 ecosystem
services at $16 trillion to $54 trillion a year, with a likely figure of
at least $33 trillion. Most of this, they said, lies outside formal
markets and is therefore not reflected in market prices, the customary
gauge of economic value. Their estimate, they said, compares with $18
trillion for the gross national product of the world, which is all the
goods and services produced by people each year.
The researchers, who based their conclusion on other published studies
and their own calculations, freely point out that their estimate is a
rough approximation, a first step that is mainly intended to determine
whether ecosystem services amount to "big potatoes or small potatoes," in
the words of Dr. Robert Costanza, an ecological economist at the
University of Maryland who headed the study. "We come away from this
thinking this is a minimum estimate," Dr. Costanza said.
Virtually everyone agrees that without the natural world, the human
economy and indeed human life could not exist. In this sense, the value of
nature is infinite, immeasurable. To some conservationists, this is all
that needs to be said. "Common sense and what little we have left of the
wisdom of our ancestors tells us that if we ruin the earth, we will suffer
grievously," said Dr. David Ehrenfeld, a conservation biologist at Rutgers
University. He said he accepted the results of the Costanza study, which
he regards as conservative, but added: "I am afraid that I don't see much
hope for a civilization so stupid that it demands a quantitative estimate
of the value of its own umbilical cord."
Dr. Ehrenfeld and some other conservationists believe that moral
arguments for saving nature are more persuasive than economic ones. But in
the view of Dr. Costanza and others, moral and economic arguments should
be pursued in parallel.
People make economic choices involving nature all the time, according
to this view, but they do so without taking all the costs into account.
For example, the dollar value of a wetland's flood-protection and water
cleansing abilities has not traditionally been considered when it is lost
to a shopping center. The result is a creeping depletion of natural
If such costs were reflected in day-to-day transactions, these
theorists say, society would pay more attention to what is lost when land
"We can't wait until we've disrupted the planet's life-support system
beyond repair," said Dr. Gretchen C. Daily, a conservation biologist at
Stanford University. She is the editor of a recent collection of papers on
the subject, "Nature's Services; Societal Dependence on Natural
Ecosystems," published as a book by Island Press. Once gone, she noted,
many of these ecological assets would be difficult, if not impossible, to
replace; it can take thousands of years to recharge depleted aquifers or
Until now, fledgling efforts at what is called "green accounting" have
been pursued largely at the national level. In a widely applauded attempt
of this kind, Dr. Robert Repetto, senior economist at the World Resources
Institute, a Washington-based research organization, has analyzed the
economies of Indonesia and Costa Rica. In Indonesia, he and colleagues
calculated that losses from soil erosion reduced the net value of crops by
about 40 percent and that the loss of value from deforestation was four
times as high as the value of the timber extracted. They also concluded
that depletion of Costa Rica's soils, forests and fisheries resulted in a
25 percent to 30 percent reduction in potential economic growth.
A nascent effort to introduce a measure of natural-resource accounting
into the United States' official calculation of economic worth was made in
1993, but it is on hold pending a Congressionally ordered study of the
soundness of the approach by the National Academy of Sciences. A report is
due this year.
The new Costanza study is not really an exercise in green accounting,
and some experts question its practical usefulness while others express
skepticism about its basic finding.
"There's no way of knowing how good this number is," Dr. Repetto said
of the study's estimate of $33 trillion for the global value of ecosystem
services. "They've made some heroic assumptions. I suppose it's useful for
rhetorical purposes." But the number, he said, is less important than the
fundamental point made by the study "that ecosystem services are
important; I don't think reasonable people would deny that."
Other experts see more utility in the analysis. The study has succeeded
in providing "a conservative estimate of what the environment does for
us," said Dr. Stuart Pimm, an ecologist at the University of Tennessee who
wrote a commentary on the Costanza study in Nature. "So often," he said,
"people concerned with protecting the environment go up against these very
highly detailed economic analyses and feel they don't have anything in
kind with which to respond." In the tables of specific ecosystem services
that accompany the study, he said, "what Costanza et al. has done is
provide a checklist" that national and local policy makers can use in
attempting to make a rough gauge of the economic worth of their natural
One table, for instance, lists specific ecosystem services, and their
supposed value, for 11 biomes, or types of natural areas. These include
the open ocean, estuaries, seagrass and algae beds, coral reefs,
continental shelves, tropical forests, temperate forests, grasslands and
rangelands, tidal marshes and mangroves, wetlands and flood plains and
lakes and rivers.
The next step, Dr. Costanza says, is to delineate more clearly the
explicit linkages between particular local ecosystems and local economies.
For example, how much of the value of the Louisiana shrimp catch is
attributable to the wetlands in which the shrimp reproduce and grow? But
since wetlands perform other services as well, the wetlands' value as a
shrimp nursery would be only a minimum indication of their overall value.
The same applies, for example, to the Catskill watershed, which serves
other economic functions besides providing and cleaning New York City's
water -- attracting tourists, for instance. "Nobody thinks the Catskills
are worth only $4 billion," Dr. Daily said, referring to the cost of
replacing the Catskills' water-cleansing function.
Assuming the value of ecosystem services could eventually be
established, how might economic policies be changed? For openers, Dr.
Daily and others say, government subsidies that distort the value of
natural resources -- in fisheries and logging, for example -- should be
abolished. Also, tax incentives might be given to landowners to protect
the long-term assets represented by natural capital rather than using them
for short-term gain.
Some experts advocate applying traditional economic arrangements to
ecosystem services. For instance, Dr. Graciela Chichilnisky and Dr.
Geoffrey Heal, economists at Columbia University, have proposed selling
investment shares in a given ecosystem. Using the Catskill watershed as an
illustration, they say that the capital thus raised would pay for
preserving the watershed. Returns to investors would come either from a
share of the costs saved by not having to build a treatment plant or, if
the investment were private, by actually selling ecosystem services. In
the case of a watershed, clean water would be sold.
But, says Dr. Daily, "the first thing is getting the prices right."
GRAPHIC: Chart: "The Value of the Natural World"
A new attempt by 13 scientists to assign dollar vlues to essential
services performed for the human economy by the natural world divides the
services into the following 17 Categories.
Carbon dioxide/oxygen balance, ozone for ultraviolet protection
Greenhouse gas regulation
Storm protection, flood control, drought recovery
Provision of water for irrigation, mills or transportation
Provision of water by watersheds, reservoirs and aquifers
Erosion control and sediment Retention
Prevention of soil loss by wind, runoff, etc; storage of silt in lakes and
Weathering of rock and accumulation of organic material
Pollution control, detoxification
Pollinators for plant reproduction
Predator control of prey species
Nurseries, habitat for migratory species
Production of fish, game, crops, nuts and fruits by hunting, fishing, gathering
of subsistence farming
Production of lumber, fuel or fodder
Medicines, Resistance genes for crops, ornamental plant species, pets
Ecotourism, sports fishing, other outdoor recreation
Esthetic, artistic, educational, spiritual and/or scientific values of
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