Page 211 - Environment: The Science Behind the Stories

Is population growth a problem? part, to the way we have intensified food production in recent
decades (pp. 263–265). Population growth has indeed con-
Our spectacular growth in numbers has resulted largely from tributed to famine, disease, and conflict—but as we shall see,
technological innovations, improved sanitation, better medical enhanced prosperity, education, and gender equality have also
care, increased agricultural output, and other factors that have helped to reduce birth rates.
brought down death rates. These improvements have been Does this mean we can disregard the concerns of Malthus
particularly successful in reducing infant mortality rates, the and Ehrlich? Some Cornucopians (p. 165) say yes. Under the
frequency of children dying in infancy. Birth rates have not Cornucopian view that many economists hold, population
declined as much, so births have outpaced deaths for many growth poses no problem if new resources can be found or
years now. Thus, our population explosion has arisen from created to replace depleted ones (pp. 165–167). In contrast,
a very good thing—our ability to keep more of our fellow environmental scientists recognize that not all resources can
human beings alive longer! Why then do so many people view be replaced. Once a species has gone extinct, for example, we
population growth as a problem? cannot replicate its exact functions in an ecosystem or know
Let’s start with a bit of history. At the outset of the what benefits it might have provided us. Land, too, is irre-
industrial revolution (p. 22), population growth was univer- placeable; we cannot expand Earth like a balloon to increase
sally regarded as a good thing. For parents, high birth rates the space we have in which to live.
meant more children to support them in old age. For soci- Even if resource substitution could hypothetically
ety, it meant a greater pool of labor for factory work. How- enable our population to grow indefinitely, could we main-
ever, British economist Thomas Malthus (1766–1834) had tain the quality of life that we desire for ourselves and
a different view. Malthus (Figure 8.5a) argued that unless our descendants? Unless the availability and quality of all
population growth were controlled by laws or other social resources keeps pace forever with population growth, the
strictures, the number of people would eventually outgrow average person in the future will have less space in which to
the available food supply. Malthus’s most influential work, live, less food to eat, and less material wealth than the aver-
An Essay on the Principle of Population, published in 1798, age person does today. Thus, population growth is indeed a
argued that if society did not limit births (through absti- problem if it depletes resources, stresses social systems, and
nence and contraception, for instance), then rising death degrades the natural environment, such that our quality of
rates would reduce the population through war, disease, and life declines (Figure 8.6).
starvation.
In our day, biologists Paul and Anne Ehrlich of Stanford
University have been called “neo-Malthusians” because they Some national governments now
too have warned that our population may grow faster than fear falling populations
our ability to produce and distribute food. In his best-selling
1968 book, The Population Bomb, Paul Ehrlich (Figure 8.5b) Despite these considerations, many policymakers find it dif-
predicted that population growth would unleash famine and ficult to let go of the notion that population growth increases a
conflict that would consume civilization by the end of the nation’s economic, political, and military strength. This notion
20th century. has held sway despite the clear fact that in today’s world, pop-
Although human population quadrupled in the past ulation growth is correlated with poverty, not wealth: Strong
100 years—the fastest it has ever grown (see Figure 8.3)— and wealthy nations tend to have slow population growth,
Ehrlich’s forecasts have not fully materialized. This is due, in whereas nations with fast population growth tend to be weak
and poor. While China and India struggle to get their popula-
tion growth under control, many other national governments
are offering financial and social incentives that encourage
their own citizens to produce more children.
Much of the concern is that when birth rates decline, a
population grows older. In aging populations, larger numbers
of elderly people will need social services, but fewer work-
ers will be available to pay taxes to fund these services. Such
concerns about the sustainability of the Social Security pro-
gram in the United States, for example, led some in the media
to call for an emphasis on increased fertility when it was
reported that the U.S. birthrate in 2011 had reached its lowest
level in recorded history.
Moreover, in nations with declining birth rates that are
also accepting large numbers of foreign immigrants, some
native-born citizens may worry that their country’s culture is
(a) Thomas Malthus (b) Paul Ehrlich
at risk of being diluted or lost. For both these reasons, govern-
Figure 8.5 Thomas Malthus and Paul Ehrlich each argued ments of nations now experiencing population declines (such
that runaway population growth would surpass food supply as many in Europe) feel uneasy. According to the Population
and lead to disaster. Reference Bureau, two of every three European governments
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