Humans
have gravely altered the chemistry, biology and physical structure
of the Earth’s land and water, according to the latest
findings on the “human footprint on Earth.” The
data showed that nearly half of the land surface of Earth
has been changed, and some 50 “dead zones” (areas
with little or no oxygen) have developed in the Earth’s
coastal waters. The latest findings, analyzed by Drs. Jane
Lubchenco of Oregon State University and Harold A. Mooney
and Peter M. Vitousek of Stanford University, show a “disturbing
negative trend in the Earth’s ability to maintain the
quality of human life,” Lubchenco stated.
Among
the findings are:
+ Close to 50 percent of the land surface of the planet has
been transformed by humans, such as filling in wetlands, converting
tall grass prairies into cornfields, or converting forests
into urban areas.
+ Humans have more than doubled the amount of available nitrogen
in the environment because of excess fertilizer use and burning
of fossil fuel.
+ Rates of extinction are 100 to 1000 times what they would
be without human-induced changes in the planet. On land, this
is largely caused by habitat loss and species invasions that
are crowding out native species. In water, this is caused
by overfishing, as well.
+ The year 1998 was Earth’s hottest on record, as human
activities continue to increase the concentrations of carbon
dioxide and other heat-trapping gases in the atmosphere.
The
Dead Zones:
Lubchenco pointed out that while human domination of land
masses is clear, the new data also indicates a dramatic alteration
of Earth’s oceans. There are now some 50 “dead zones”
in the world’s coastal areas, she reported. The largest
in the Western Hemisphere is in the Gulf of Mexico, caused
by excess nitrogen and phosphorus flowing down the Mississippi
River. “We’ve long thought of oceans as having
an infinite ability to provide food and other goods and services
to humans. But the massive human-wrought changes in our oceans
are impairing their ability to function as we assume they
will,” stated Lubchenco, who is a Distinguished Professor
of Zoology at Oregon State University. “We’re
degrading the water, changing our coastlines, filling in our
estuaries, and changing our rivers,” Lubchenco said.
“And we’re witnessing many signals of the problems
that will result from these changes, including toxic algal
blooms, coral bleaching and sudden disappearance of fish from
key fisheries.”
Human
Degradation of Waterways:
Lubchenco reported on a number of indications of the human
degradation of the Earth’s waterways:
+ Half of the mangrove forests, which serve as estuaries in
the tropics, have been lost to a combination of coastal development
and conversion to aquaculture.
+ Global aquaculture now accounts for more than one-quarter
of all fish consumed by humans. In the case of shrimp and
salmon – the fastest growing segment of aquaculture –
two to three pounds of fish are needed to grow one pound of
the raised seafood. Thus this practice is depleting the oceans
of food for wild fish, birds, and marine mammals.
+About 3000 species of marine life are in transit in ballast
water of ships around the world, resulting in a serious invasion
of non-native species in our waterways. A minor but increasing
contributor to the problem is escape of non-native fish and
plants from aquariums.
Changes
Will Disrupt Range of Services:
According to Lubchenco, the global-scale changes that
we have set in motion will impair the Earth’s ability
to provide a wide range of services to human life. “In
addition to the direct services of food, fiber, shelter, and
medicines, many other interdependent services are being disrupted,”
Lubchenco stated. For example, forests, grass-land and coral
reefs contribute to flood control and climate regulation.
Mangroves, estuaries, coral reefs, and kelp forests protect
shores from erosion and provide nursery areas or spawning
habitat for economically important species. Massive changes
in the Earth’s environment have far-reaching implications
that result in con-flicts across political boundaries, Lubchenco
said. “Scarce resources such as water or fishing rights
lead to battles between states and nations. Environmental
degradation resulting in food shortages lead to civil unrest
and migration into neighboring countries,” Lubchenco
explained.
Increasing economic inequities
in the world raise a host of new issues, according to the
researcher. “Inhabitants of poorer nations are less
able to buy supplies such as bottled water if the water is
polluted, less able to influence important policy decisions
such as the choice of a site for a toxic waste dump,”
Lubchenco said. The groundbreaking 1997 work of Lubchenco
and her colleagues documented that we now live on a human-dominated
planet, with the growth of the human population and the amount
of resources used are altering Earth in unprecedented ways.
Her current analysis updates these findings. “The
dramatic rise in our population simply exacerbates the problems,”
Lubchenco stated, noting that as of July 17, 1999, there are
reportedly six billion people on Earth, a doubling in less
than 40 years.
Signs
of Hope:
Lubchenco did see hopeful signs in the increasing number
of people who are concerned about the environment and are
willing to take action. She noted that “it is encouraging
that there is an increasing focus on the part of the private
sector, religious groups, and individual citizens to take
responsibility and undertake innovative action. As
inhabitants of earth, we need to take stock of these massive
changes, understand their impli-cations, and change our direction,
” Lubchenco said. “We are currently inattentive
stewards. It is in our best interests to be more fully engaged
in ensuring our own health, prosperity and well-being.”
Lubchenco strongly advocated additional research “so
that we can make more informed decisions about our ecosystems.”
Substantial
research across all disciplines is called for in a new policy
report, from the National Science Board, Environmental Science
and Engineering for the 21st Century: the Role of the National
Science Foundation. Lubchenco, who chaired the Board’s
Task Force on the Environment which prepared the report, equates
the need for scientists to focus on environmental research
today with the nation’s past decisions to invest in science
to con-quer disease, win the Cold War, or win the “space
race.”
