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OCR for page 49
5
Humanity: An Agent of
Global Environmental Change
The automobile, one of the most pervasive symbols of mod-
ern culture, serves as an apt metaphor for the ways in which
humans change the global environment. Automobiles emit car-
bon dioxide that adds to the buildup of greenhouse gases in the
atmosphere, nitrogen oxides that react in the atmosphere and
rain down as acid deposition, and other gases and particulates
that contribute to smog and local air pollution in our urban
areas.
Today there are 500 million registered automobiles through-
out the world, each of which burns an average of nearly 2
gallons of fuel a day. Automobiles consume one third of the
world's production of oil. As the population grows, so will
the number of automobiles. In addition, the average number
of automobiles per person is going up, and the number of au-
tomobiles is increasing faster than the population, particularly
in developing countries. Some estimate that if current trends
continue, by 2025 there will be 4 times as many automobiles as
there are today.
Paul Ehrlich, a population biologist at Stanford University,
49
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50
THE EARTH AS A SYSTEM
and John P. Holdren, an expert on energy and resources at Berke-
ley, pointed out in the early 1970s that the damage that humans
cause to the environment is a product of three factors: the total
number of people, how much each person consumes to main-
tain his or her standard of living, and how much environmental
damage is incurred in producing the goods consumed. To pur-
sue the automobile metaphor a moment longer, the same can be
said for the environmental damage caused by automobiles or,
for that matter, factories or other manifestations of society. For
instance, the future environmental damage from automobiles
depends not only on the total number of people owning them
and the rate at which the number of automobiles per person in-
creases but also on how much pollution each automobile emits.
There are also signs that trends can be reversed. While ad-
vances in technology in the early 1900s made it possible for the
automobile to preempt the horse as a mode of transportation,
technology has also reduced the amount of pollutants emitted
from each automobile. In the United States, for example, ni-
trogen oxide emissions from automobiles dropped substantially
once catalytic convertors were required In all new cars.
Ehrlich and Holdren's equation embodies a simple and
powerful truth. Our ability to change the global environment in-
creases along with our numbers, our quest for and achievement
of affluence, and our technological and institutional capabilities
(which can also provide means to alleviate environmental ciam-
age). These intertwining factors, the product of decisions made
by individuals and societies around the world, are the main
forces driving change in the global environment.
POPULATION, AFFLUENCE, AND TECHNOLOGY:
HOW HUMANS CHANGE THE ENVIRONMENT
A discussion of the human causes of global environmental
change would not be complete without mention of the pressures
that the sheer numbers of people inhabiting the earth place on
the environment. Between 1950 and 1987, the global population
doubled from 2.5 billion to 5 billion. This increase in the span
OCR for page 51
HUMANITY
11
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1750 1800 1850 1900 1950
YEAR
51
2000 2050 2100
Population growth, 175~2100. (Reprinted, by permission, from Thomas W. Merrick
et al. 1986. "World Population in Transition," Population Bulletin, vol. 42, no. 2, Figure
1, p. 4. Copyright 2) 1986, Population Reference Bureau, Inc.)
of less than 40 years equaled the total increase in the worId's
population from the time the human species first emergect until
the middle of the century. The United Nations estimates that by
2025 our numbers will increase to S.5 billion before stabilizing
at over 10 billion by the end of the coming century. N~nety-
five percent of the population growth will be in developing
countries.
This enormous increase in the numbers of people over the
past century and the eventual stabilization in the total number
of people are the product of the "demographic transition." With
the industrialization that began in the last century in what is
now the developed world, improvements in public health and
medical advances caused death rates to decline. The improved
socioeconomic conditions and access to health care and educa-
tion that followed led to a drop in birth rates. When declining
birth rates catch up with declining death rates, population even-
tually stabilizes. Indeed, the current net population growth in
developed countries is generally very low.
In the developing world, in contrast, death rates have de-
clined, but birth rates have not yet fallen enough to compensate.
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52
THE EARTH AS A SYSTEM
The result is the very rapid population growth in developing
countries that we see today. However, birth rates in many devel-
oping countries have begun to taper off in the past few decades,
although the rate of decline differs among countries. In many
African countries, for example, demographers expect that rates
of population growth will not decline until at least the end of
this century.
Demographers base their predictions of the world's future
population on assumptions about how quickly birth rates will
decline. If the rates do not decline as rapidly as assumed, the
world's population will grow even faster than the United Na-
tions currently predicts.
The explosion in the numbers of people inhabiting the earth
is significant because, at the very least, each of these people re-
quires food, clothing, and shelter. Growing numbers of people
cut forests for land to grow food or graze cattle, with global
consequences for the hydrologic cycle, the ability of the land
to sustain agricultural productivity, and the earth's genetic re-
sources as millions of plant and animal species are driven to
extinction. Growing numbers of people in industrialized and
industrializing societies use energy derived from fossil fuels to
travel, produce goods, and apply advanced agricultural tech-
nologies, with global consequences for atmospheric concentra-
tions of greenhouse gases, climate, and ecosystems.
But the impacts that the expanding numbers of people are
having on the global environment are not solely a matter of
the numbers of people; they also reflect how humans and the
societies they live in use natural resources (which is, in turn,
driven by economic and political structures as well as social
values and norms). Societies use the air, water, and land as
repositories for the waste products from industries that produce
the goods that are consumed. They use fuel to drive cars, heat
homes, and power industries. They convert raw materials such
as wood and metals into consumer products and allocate land
and fodder for animals that become food. If these resources
are used in ways that emit excessive pollutants, clear forests,
or deplete the soil of nutrients, the more societies consume to
OCR for page 53
HUMANITY
53
satisfy their standard of living, the greater the damage to the
environment.
The earth's inhabitants clo not exert equal pressure on the
environment. Each person in an industrialized country uses far
more natural resources and generates far more waste through-
out his or her lifetime than a person in a developing country.
The wealthy countries of the world constitute about one quarter
of the global population but consume 80 percent of the worId's
commercial energy. Stated another way, each person in a devel-
oped country consumes on average about 32 barrels of crude
of} per year, whereas a person in a developing country con-
sumes only about 3.5 barrels. Energy use in many developing
countries has been growing faster than population growth, but
developing countries still consume 4 to 7 times less energy per
person than their counterparts in the developed world.
Thus carbon dioxide, the predominant greenhouse gas pro-
duced as fossil fuel is burned for energy, is disproportionately
emitted as a result of energy consumed in the industrialized
countries. About 40 percent of all carbon dioxide builcting up
in the atmosphere is emitted from seven wealthy countries in
North America and Western Europe. These seven countries
make up only I! percent of the worId's population.
While the numbers of people and their levels of affluence
clearly influence the environment, the kind of technology used
ultimately determines how much pollution is emitted or what
kinds of and how much raw materials are used. In many in-
dustrialized countries, technologies to control emissions have
in recent decades led to significant improvements in the air
quality of many cities and the water quality in many lakes and
rivers. Meanwhile, the amount of energy used to produce a unit
of gross national product known as the energy intensity- has
declined in the industrialized world, by one fifth between 1973
and 1985. In the United States, according to John H. Gibbons,
director of the U.S. Congress's Office of Technology Assessment,
and colleagues, the gross national product grew 40 percent in
these years while energy consumption remained constant.
Many who study technological trends perceive industrial
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HUMANIl-Y
55
economies to be undergoing a process of "dematerialization," a
decline in the weight of materials and the amount of energy con-
sumed in providing a given product or service. Undoubtedly,
many consumer products such as automobiles, televisions, and
calculators have become lighter and smaller. This trend means
people can maintain a certain standard of living while using
smaller amounts of raw materials and energy and creating less
waste. But, as Robert Herman, of the University of Texas at
Austin, and colleagues Siamak Ardekani, of the University of
Texas at Arlington, and Jesse Ausubel, of The Rockefeller Uni-
versity in New York City, note, some trends may counterbalance
these benefits. People migrating from urban to suburban areas
require more roacts, single-unit houses, and automobiles and
demand more products as the definition of "basic necessities"
changes. Such tendencies could offset some of the savings in
waste, energy, and raw materials achieved through dematerial
· -
Gabon.
Continued industrial development has serious implications
for the future global environment, particularly if developing
countries adopt older technologies that generate more pollu-
tion and consume more energy than more modern technologies.
Clearly, though, economic growth is required to break the cycle
of poverty and high birth rates that itself causes severe environ-
mental damage to the soils, water, forests, and wildlife in many
developing countries around the world. The experiences of de-
veloped and developing countries alike indicate that improved
standards of living-adequate shelter, fuel, and clothing, as well
as access to education, health care, and employment led to a
sustained reduction in birth rates. Whether this was because
of improved access to birth control or greater rights for women
or because with socioeconomic development parents no longer
need many children to ensure financial security is a complex
question. Nevertheless, the fact remains: As economies have
grown and standards of living have improved, birth rates have
declined.
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56
THE EARTH AS A SYSTEM
CHANGING THE FACE OF THE EARTH:
AGRICULTURE AND INDUSTRY
Humans do not tread softly on the earth. In fact, the effect
of human activity is so pervasive that In just a few centuries the
earth's surface has been transformed such that in many places
its original state is difficult to imagine, much less restore. This
transformation wrought by the immensity of human numbers,
by increasing affluence, and by technology has captured the
popular imagination in recent years as more people realize that
their world, and their children's futures, may be jeopardized
by unchecked environmental changes. The recognition that hu-
mans are a powerful agent in transforming the earth dates back
much further, however. George Perkins Marsh in the nineteenth
century, the Russian mineralogist W. T. Vernadsky in the first half
of this century, and contributors to the now classic work, Man's
Role in Changing the Face of the Earth (1956), edited by William L.
Thomas, Jr., each expressed the ties between the global environ-
ment and human development.
B. L. Turner Il. who heads the program on The Earth as
Transformed by Human Action, at Clark University, points out
that two types of transformations of the earth most affect the
global environment: changes in how humans use the land, most
notably for agriculture, and changes in industrial capabilities.
Over the past three centuries or so, as the area of land used
for agriculture spread and the global economy expanded, hu-
mans were increasingly prone to adapt land to suit their own
purposes. This control is most visible in the profound changes
in the vegetation that covers the earth's surface. The land area
devoted to cropland has expanded by 450 percent in the past
300 years, amounting to a world increase of about 12.4 million
square kilometers. The net loss of forests due to human action
from the time humans first began cutting trees amounts to 15
to 20 percent of the worId's forested area, or about ~ million
square kilometers. Also in the past three centuries, the popula-
tion of the 40 largest urban areas increased about 25-fold, with
an even greater increase in estimated urban area. Such changes
OCR for page 57
HUMANITY
57
have drastically altered the earth's surface, as well as the en-
ergy balance, the hydrologic cycle, the emissions of biologically
produced gases to the atmosphere, and the vegetation.
Industrial clevelopment, too, has a potent effect on a global
scale, through pollutants and other materials that are introduced
into the biosphere, atmosphere, and oceans. Industrial devel-
opment has vastly improved human well-being, but there have
been unexpected side effects. ChIorofluorocarbons (CFCs) were
invented around 1930 and were hailed, for instance, as safe al
ternatives to ammonia and other coolants that had a tendency
to leak and cause explosions when used in home refrigerators.
No one could foresee the repercussions of these seemingly safe,
stable, and inexpensive compounds on the global environment.
Certainly, no chemist imagined that CFCs destroy the ozone
layer about 25 miles above the earth, which shields us from
solar ultraviolet radiation, or that CFCs contribute roughly 25
percent of the warming caused as greenhouse gases build up in
the atmosphere.
Other examples abound of what Paul Gray, president of
the Massachusetts Institute of Technology, calls the "paradox
of technological development." Writing in the 1989 National
Academy of Engineering publication Technology and Environ-
ment, Gray observed that "New technology will be applied in
ways that transcend the intentions anc! the purposes of its cre-
ators, and new technology will reveal consequences that were
not anticipated." A few decades ago, asbestos fibers were hailed
as a breakthrough for fireproofing ships, schools, and office
buildings, but today they are known to cause Jung cancer. The
"green revolution" that improved food production around the
world and enabled countries such as India to become net ex
porters rather than importers of food has contributed to the
chemical pollution of rivers, lakes, and seas because it relies
heavily on the use of insecticides and fertilizers.
Energy is fundamental to inclustrial development, and the
sources used to derive that energy have had particular impli-
cations for the environment. With the Industrial Revolution In
the early 1800s, fuel wood and water power gave way to coal
OCR for page 58
58
THE EARTH AS A SYSTEM
50
45
40
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30
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1860 1880 1900 1920 1940
YEAR
1960 1980 20~00
Trend for U.S. fossil fuel consumption (in British thermal units, BTUs) since 1850.
Data for 1850 to 1880 from U.S. Bureau of the Census (1975); data from 1880 to
1932 from U.S. Geological Survey, Yearbooks (1880-1932); data from 1933 to 1980
from U.S. Bureau of Mines, Mineral Yearbooks (1933-1980). (Reprinted from National
Research Council. 1986. Acid Deposition: Long-Term Trends. National Academy Press,
Washington, D.C.)
and coal-based technologies such as iron smelting and steam
engines. By the early 19OOs in the United States, coal, which
generates large amounts of carbon dioxide and other pollutants,
supplied most of the energy for the nation's factories. Industri-
alized countries currently generate between 20 and 30 percent of
their energy from coal. Natural gas, which currently provides
about one fifth of the worId's commercial energy, generates
fewer pollutants and less carbon dioxide than any other fossil
fuel.
Today, fossil fuels (oil, natural gas, and coal) supply SS
percent of the worId's commercial energy, and nuclear energy
provides the rest. In many poor countries, noncommercial fuels
such as wood, dung, and crop waste still provide much of
OCR for page 59
HUMANITY
59
the energy for cooking and heating. Clearly, the future of the
global environment depends to a large extent on the sources of
energy for current and future societies and the amount of energy
consumed.
THE FUTURE
The global consequences of industrial development as prac-
ticed today cannot be denied. Waterways, soils, and forests
bear the signature of acid deposition; the annual hole in the
ozone layer marks human-induced depletion of this protective
gas. These environmental changes may be unacceptable costs
of progress, and yet development must continue, albeit in a less
damaging form. The gap between rich and poor can be nar-
rowect only by the economic development necessary to meet the
needs and aspirations of the worId's poor today, as well as the
needs and aspirations of tomorrow's growing population. The
challenge, in the words of km MacNeill, director of the Environ-
ment and Sustainable Development Program at the Institute for
Research on Public Policy in Ottawa, Canada, and a contributor
to Our Common Future, the 1987 report of the U.N. World Com-
mission on Environment and Development, is to "emphasize the
possibilities for a 'new era of growth'-not the type of growth
that dominates today but sustainable growth, growth basect on
forms and processes of development that do not undermine the
integrity of the environment on which they depenct."
In one such approach, Robert Frosch and Nicholas Gal-
lopoulos, of General Motors, suggested in the 1989 Special Issue
of Scientific American that the traditional mode! of industrial
activity in which individual manufacturing processes take in
raw materials and generate products to be sold and waste to
be disposed of should be transformed "into a more Integrated
model: an industrial ecosystem." Like its analog in the biolog-
ical ecosystem, such an industrial ecosystem would optimize
consumption of energy anct materials, minimize waste gener-
ation, and use the effluents of one process whether fly and
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60
THE EARTH AS A SYSTEM
bottom ash from electric-power generation or discarded plas-
tic containers from consumer products as raw materials for
another process.
Just as humans can transform the face of the earth, we can
also mitigate some of the adverse effects. Methods exist that
could shape the future environment, including regulatory con-
tro! and market adjustments in which prices of goods account
for the environmental damage they produce (the price of gaso-
line could, for instance, reflect the costs associated with smog,
global warming, or acid deposition), as well as changes in social
values and norms. William Ruckelshaus, former head of EPA,
notes that history offers examples in which nations have mobi-
lizecl to synthesize short-term interests with longer-term goals.
During World War IT, for instance, when people believed that
the nation's survival was at stake, seemingly impossible politi-
cal and economic changes were accomplished in a remarkably
short time. The entire U.S. population was mobilized: Work pat-
terns changed, prices and supplies of goods were manipulated
and controlled, and the nation's industrial plants were swiftly
reorganized.
Even though government agencies and international organi-
zations are structured to deal with environmental and economic
issues separately, these issues are in fact interlocked. "Global
warming is a form of feedback from the earth's ecological system
to the worId's economic system," MacNeill observes. "So are
the ozone hole, acid rain in Europe and eastern North America,
soil degradation in the prairies, deforestation and species loss
in the Amazon, and many other environmental phenomena."
These phenomena are the faces of global change.
Representative terms from entire chapter:
global environment
