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World
Population Change: Boom or Bust?
This is an e-Lecture
(text and Web links)
version of a presentation on the economics of population change that we have
done at several conferences in Wisconsin and Georgia. This e-Lecture could be
used by teachers for classes in economics, geography, world affairs,
social problems, and other social studies courses. It may be
used either independently or in conjunction with the Web based audio file
interview with the authors .
Y6B
The
year 1999 was designated as Y6B by organizations concerned with world
overpopulation issues. Y6B stands for the year
of 6 billion people. The world population was estimated to reach
that number on October 12, 1999.
As
of July 1, 2001, the U.S. Census estimates world population at 6,157,744,000
people. A good explanation and analysis of the data for world population
is at the U.S. Census Bureau Web
site. Although the world has added one billion people in the last 12 years,
the very important population growth rate has begun to slow down. From a
record high annual growth rate of 2% in 1968, it has declined to 1.4% in
2000. That is a 30% decrease in the rate of growth, and it will have
significant effects on future demographic developments. An excellent source
of
recent world demographic data
is the Web site of the Population Reference
Bureau.
Population:
The First Essay, 1798
One of the first economists
to study population change was
Thomas Robert Malthus
in his extended essay published in 1798. He forecasted a dismal
future for the human race based on mathematical analysis. He postulated
that the human population would grow exponentially while food production would
increase linearly and therefore "the power of
population is indefinitely greater than the power in the earth to produce
subsistence." Eventually population would be checked by
"misery and vice" in the form of famine, disease, and war.
This tragic scenario led to
economics being known as the "dismal science."
See the Web site
by that name The Dismal Scientist.
Contemporary advocates of
Malthus' ideas are referred to as "neo-Malthusians." They expand
his concepts beyond food production to all goods, services, and environmental
quality. (See ZPG
and Worldwatch ).
"From
Malthusian Stagnation to Modern Growth"
In the American Economic
Review, May 1999, Oded Galor and
David Weil categorize past and current population growth into three distinct
regimes: Malthusian,
Post-Malthusian, and Modern Growth.
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The Malthusian
regime consists of very slow
population growth due to high birth rates and high death rates.
This regime dominated human history until approximately 1700-1800. This
regime was characterized by a very low rate of technological change, a stagnant
level of per capita income, and a positive correlation between income and
population growth. Economists would further add a concept called the
"law of diminishing returns." This "law" makes it
difficult for food production to keep up with population growth.
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The post-Malthusian
regime is characterized by high birth rate and low death rates.
This is a dramatic stage of the demographic transition. The population
grows very rapidly, the rate of technological change increases, and
there is a positive relationship between income and population growth.
However, income per capita is generally increasing as technological change
overwhelms diminishing returns. In the 1800s and early 1900s, this regime
characterized European nations and other industrialized regions. Many less developed
countries continue to exhibit these characteristics. Our concern and
preoccupation with the "population explosion" dates from this period.
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The modern growth
regime is characterized by low birth rates and low death rates.
Furthermore, fertility rates (number of births per woman in her lifetime)
decline significantly. Technological change accelerates, and a negative
correlation develops between income per capita and population growth. As
the incomes of families rise, the numbers of children they have declines.
The Population Reference Bureau
put together a history of the world population and trends which are occurring
in the population. The following graphs are from their web
site. The graphs range in size from 28 KB to 35 KB, so expect
a few seconds delay while the images load.
Decline
in World Fertility Rates
As stated above, world fertility rates have been declining dramatically
for the last fifty years. From a high of 5.0 children per woman in 1950,
the fertility rate has decreased by 44% to 2.8 children per woman in
1999.
Even more impressive is the decrease in the fertility rate for women in
the high income countries of the world (More Developed Regions: MDRs) to 1.6
which is well below the replacement level of 2.1. As the chart
indicates, fertility rates in all regions have fallen significantly, with Africa
being the only remaining area with a very high childbearing rate. Some
current fertility rates from a sample of countries are:
United States: 2.06
Italy: 1.18
Spain: 1.15
Ukraine: 1.26
Zambia: 5.62
China: 1.82
India: 3.11
Why did
fertility decline?
There are many reasons why fertility rates have
declined. Reasons that are primarily non-economic
include:
Lower child mortality is
especially important because if the goal of parents is to have a certain number
of surviving children, then they can achieve their goal with less
births. Decline in
Infant Mortality
Economic reasons for the decline in fertility
rates include:
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high rates of urbanization increase the
cost-benefit ratio of children,
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increased education of women has raised their
earning power and increased the "opportunity cost" of child bearing and child
rearing,
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rapid technological change has raised the
rate of return to human capital and education. High rates of return to
human capital and education has raised the incentives of parents to invest in
their children's education and to substitute quality for quantity in family size
decisions.
Urbanization of the population
Future
of population change?
Predicting future demographic trends is highly
uncertain. However, the crucial determinate of long-run trends in the size
of the world's human population is the fertility rate or average number of
children per woman. The trend in that fertility rate is down in virtually
every country in the world. Causing and reinforcing that decline are
several important economic and non-economic variables discussed above.
Although there is powerful momentum in the near future for large increases in
the population because of the large numbers of women of childbearing age, in the
longer run of 100-150 years, there is strong evidence that world population will
stabilize and probably decline from current levels. This optimistic
development is one of three scenarios depicted in the United Nations population
projections . Their projections are highly dependent on future trends in fertility
rates.
Finally, there are important political, social, and economic
consequences of the changes in population discussed above. The much lower
fertility rates in the high income MDRs will vastly increase the proportion of
the world's population that will live in the poor developing nations. The
decline in world fertility rates will create an age distribution much older than
at present with fewer workers available to support the rising numbers of elderly
people. These changes will challenge our domestic social system and our
international political system.
Additional Resources
This e-Lecture may be used
by teachers for classes in economics, geography, world affairs, social problems,
and other social studies courses. It may be used either independently or
in conjunction with the Web based learning resources and
audio file interview
with the authors .
This
presentation was developed by Larry Weiser, Director of the Center for
Economic Education at University of Wisconsin-Stevens Point, in collaboration
with Bob Enright, Professor of Sociology at UW-Stevens Point, and with
additional contributions from George Langelett,
Assistant Professor,
South Dakota State University.
EconomicsWisconsin
Wisconsin Council on Economic Education
161 W. Wisconsin Avenue, Suite 3143
Milwaukee, WI 53203
(414) 221-9400
Fax (414) 221-9790
wicnclee@ameritech.net
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