Issue of
July 30, 1997
 
|
|
The whole world
really is in our hands,
leading ecologists assert
BY JANET BASU
And God blessed them,
and said unto them, "Be fruitful, and multiply, and
replenish the earth, and subdue it: and have dominion
over the fish of the sea and over the fowl of the air,
and over every living thing that moveth upon the
earth." Genesis 1:28
It took a strong dose of chutzpah
for the writer of Genesis to imagine that Adam and
Eve held dominion over "every living thing,"
over beasts as ungovernable as tigers and whales, forces
as terrifying as plague and drought. Now, thousands of
years later, some of the world's most respected
scientists are saying that this dominion is now
accomplished. Human activities have so much impact that
we have become a "force of nature" in our own
right.
Related
Information:
In a special section of
the July 25 issue of Science, scientists from
Stanford and elsewhere document the ways in which humans
are transforming the land, the water and even the
atmosphere of Earth more rapidly and at a greater scale
than these things have been changed at any time in the
history of our species. They suggest actions that can be
taken to slow the pace of change by using resources more
sustainably.
"In a very real
sense, the world is in our hands. . . . Humanity's
dominance of Earth means that we cannot escape
responsibility for managing the planet," say the
authors of the lead article. They are Stanford biological
sciences Professors Peter Vitousek and Harold Mooney;
ecologist Jerry Melillo of the White House Office of
Science and Technology Policy; and marine ecologist Jane
Lubchenco of the University of Oregon, who is past
president of the American Association for the Advancement
of Science.
The special issue of Science
includes five other scientific papers documenting the
extent to which ecosystems are dominated by humans, plus
a news section and an editorial by Gro Harlem Brundtland,
a leading environmentalist and the former prime minister
of Norway.
Every organism modifies
its environment, said Vitousek, who is the Clifford G.
Morrison Professor of Population and Resources Studies,
and when it comes to humanity's impact, we usually think
of "human-dominated ecosystems" in terms of
plowed fields, harvested forests and urban landscapes.
"Now, that term applies with greater or lesser force
to all of Earth," he said. "Many ecosystems are
dominated directly by humanity, and no ecosystem on
Earth's surface is free of pervasive human
influence."
Lubchenco said, "We
tend to think of the forces of nature as being massive
geological cataclysms like volcanoes or floods or
hurricanes. Humans, by virtue of our numbers and our
technical capabilities, have emerged upon the scene as a
major force of nature [as well]. It has happened very
quickly, and it already has resulted in unanticipated,
major consequences."
Lubchenco spoke in a
telephone interview from Washington, D.C. By coincidence,
on July 24, the day before the Science special
issue was published, she and six other scientists,
including Stanford climatologist Stephen Schneider,
briefed President Clinton and Vice President Gore on one
aspect of human-caused global change (see
related story).
In their Science article,
Vitousek, Mooney, Lubchenco and Melillo present an
overview of the major ways that the human enterprise has
transformed the planet, and suggest methods to manage
this transformation so that the species and ecosystems we
depend on can be sustained for the future.
Among their examples of
human impact:
- The carbon dioxide
concentration in the atmosphere has increased by
nearly 30 percent since the beginning of the
Industrial Revolution.
- More than half of all
accessible fresh water is used by humans.
"Of all the environmental security issues
facing nations, an adequate supply of clean water
will be the most important," the scientists
predict.
- One-third to one-half
of Earth's land surface has been transformed by
human action. Some changes have been to
humanity's benefit; some have altered or
destroyed ecosystems that we depend on, both on
land and in nearby waterways.
- About a quarter of
the bird species on Earth have been driven to
extinction.
- Two-thirds of marine
fisheries are fully exploited, over-exploited or
depleted.
- Humans have deposited
long-lasting, toxic chemicals in soil and water
around the globe; we've also rearranged the
world's living organisms with global transfers of
invasive species that crowd out the natural
habitats of birds and animals.
- Humanity fixes more
nitrogen from the air than is fixed by all
natural processes combined. Nitrogen, essential
for plants to grow, must be chemically altered or
"fixed" to be usable. While abundant
usable nitrogen is good for crops, it also
supports invasive species. Along coastlines,
nitrogen from fertilizer run-off feeds algal
blooms including toxic "red tides."
Mooney, who is the Paul S.
Achilles Professor of Environmental Biology, said that it
is both the massive scale of global change and the
rapidly accelerating rate of change that scientists are
concerned about. Mooney, past president of the Ecological
Society of America and currently secretary-general of the
International Council of Scientific Unions, the
"United Nations" of scientific societies, said
that given time, most ecosystems adjust to change. But
too much change at an accelerated rate could leave vast
areas depleted of key species and the complex web of life
that they and we depend on.
"The rates, scales,
kinds and combinations of changes now are fundamentally
different from those at any other time in history,"
Mooney and his co-authors write. "We are changing
Earth more rapidly than we are understanding it."
They called for work to reduce the rate of change, to
stabilize the human "footprint" on the planet
at a level that can sustain most species. That would
involve slowing human population growth, and using
resources efficiently so the wastes and byproducts of
human activity do less harm to the environment.
They also called for
accelerated efforts to understand human-caused global
change, with more ecological research as well as more
work to understand the social, economic and cultural
forces that drive human actions on the environment.
"The message from the
scientific community is clear," said Lubchenco.
"We are beyond arguing about the science. We know
enough to act. Our future and the quality of our future
depends on the extent to which we recognize our impact
[on the Earth] and take responsibility for using this
power wisely." SR
|
