Demographic Transition:
An Historical Sociological
Perspective
Jump to: [Introduction][Population Energy and Urbanization][Two Demographic Transitions][The
Past Demographic Transition][The Present Demographic Transition][Mitigating Global Environmental
Change][Self-Test]
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Introduction
As the following figure illustrates, historically human population has grown very
slowly. However, this pattern has been disrupted within the last two centuries by
exponential human population growth rates. World population now stands at 6 billion
and is projected to continue growing through this century.
This rapid population growth has been associated with global environmental changes
including:
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increasing greenhouse gas emissions that may produce dramatic climatic
change, and the destruction of tropospheric ozone
toxification of the soil, air, and water
Environmental degradation such as deforestation
Loss of biodiversity
Population Energy and Urbanization
Population growth did not occur in a vacuum. It was closely associated with major
changes in technology and social organization: essentially with the transformation to
fossil fuels and the rise of urban industrial society.
Fossil fuels made possible the rapid growth of population as transportation cost were
reduced and human productivity increased greatly. Along with population growth
came increased demands for energy, while urbanization and the resulting industrial
revolution provided the setting for increased human productivity. Together,
increased energy consumption and population growth have produced major forms of
environmental degradation.
Two Demographic Transitions
To understand this overall pattern of population growth, it is useful to review a basic
condition of demographic history, known as the demographic transition: the
change of a population from high birth and death rates to low birth and death rates.
It is a simple definition, but an exceedingly powerful one, for it shows clearly a major
transformation of human reproduction. The demographic transition generally occurs
in four stages. In the initial stage, both birth and death rates are high, causing only
slow and steady population growth. In the next stage, death rates begin to decline
and birth rates remain high, resulting in faster population growth. In stage three, the
birth rate begins to decline, and in the final stage, birth rates balance death rates.
Population growth stabilizes in this final stage. In some cases, such as Italy,
population growth may cease altogether.
The following two charts illustrate this change.
The Past Demographic Transition
England and Wales experienced a demographic transition characterized by slow and
steady change. From 1700, the death rate began a long gradual decline. The decline
was initially due to three factors: the first was the trade revolution, which introduced
new foods such as potato and maize (corn) from the Americas. The second was the
agricultural revolution that brought about higher yields of food production locally
through the use of new agricultural practices. Finally, the industrial revolution that
made new goods available. All of these changes were gradual, and increased the
general standard of living for the population, without major medical
breakthroughs. While death rates fell, the birth rates remained high, as both
cultural norms and expectations and need for productive labor at home made
immediate downward adjustment in the birth rate difficult to attain. As life in an
urban industrial society made large families neither necessary for labor nor desirable
for cost reasons, the birth rate declined over one or two generations. The
intervening period saw a dramatic rise in the annual rate of population growth, to
about 1 percent per year.
It is important to note that this same transition seen in England and Wales took
place in every industrialized country in the world (all of Europe and Russia, North
America, Australia and New Zealand and Japan). All went from high birth and death
rates in traditional, rural-agrarian societies to low birth and death rates in modern
urban-industrial societies, though the dates and rates of change vary considerably.
The Present Demographic Transition
Today, the same demographic transition is occurring throughout the world’s less
developed countries, though the chart shows some dramatic differences with the
past transition. First, birth and death rates start at higher levels, for reasons that are
not at all clear. Second, death rates have declined much more drastically, moving as
much in one generation as it had in the past in two centuries. Third, the cause of the
mortality decline lies in the development of new medical and public health
technologies, based on anti-bacterial chemicals and insecticides that reduce disease
vectors. Rapid mortality declines without concomitant fertility declines means higher
rates of population growth are occurring. Where growth rates reached one percent
per year in Europe, they have recently reached over 3 percent per year in parts of
Asia, Africa and Latin America. The birth rate is now beginning to fall. When this
happens, as it has in parts of Asia and Latin America, it can come very quickly,
declining from traditional to modern levels in a decade or two, rather than in a
generation or two. Along the same lines as the mortality declines, the fertility
declines are in large part the result of new medical, mainly contraceptive,
technologies.
The mortality declines and the new contraceptive technology have also produced
some revolutionary changes in public policy. Up until 1952 most governments of the
world were pro-natalist, and were actively opposed to any form of birth control. In
1952 India became the first country to adopt an official policy to reduce population
growth by reducing fertility within marriage. This called for the formation of a
national family planning program to spread the new contraceptive technology. Since
1952, almost all less developed regions have undergone the same or a similar policy
change: they now officially permit or are actively attempting to reduce population
growth by reducing fertility.
The results have been mixed. Some countries have experienced a very rapid
fertility decline, experiencing a simultaneous substantial increase in the health of
women and children. Other countries have made almost no progress. They continue
to show high fertility and population growth, along with high levels of maternal and
child mortality and very low levels of education and social welfare.
The following charts show another aspect of these mixed results. They illustrate the
Total Fertility Rate, or roughly the number of children a woman will bear in her
reproductive life.1 China and Thailand show how rapidly the fertility rate can fall.
Today all of East Asia has low fertility. Southeast Asia is close behind, as is most of
Latin America. Africa, especially south of the Sahara is further behind: most
countries still experience high fertility and are just beginning what is expected to be
a decline to low fertility.
Costs of Rapid Population Growth
Rapid population growth impedes economic development, helping to keep a country
poor, and thus further promoting rapid population growth
Rapid population growth reduces health and welfare, especially of women and
children. Rapid growth implies women giving birth from a younger age, experiencing
more pregnancies throughout their lives, and bearing children well into their later
years. All three are known to cause higher rates of infant and maternal mortality.
The first impact of reducing fertility is increasing the health and welfare of women
and children.
Rapid population growth increases number and proportion of young people in the
society. This increases the demand for education and jobs. Where education and jobs
are not available, young people, especially young males, who constitute a highly
volatile population, can easily be swayed to violence by demagogic leaders.
The following chart shows how fertility is related to the growth of the young (15-19
year olds) male population.
Both Thailand and the Philippines began with roughly the same sized population in
1950, 20 million, of which young males accounted for about 10 percent, or 2 million.
Thailand had a slightly lower fertility rate in the 1950s, but the real difference came
in the 1960s when Thailand began what has become one of the world’s most
successful national family planning programs. The Philippines lagged behind because
its family planning program was held hostage to religious resistance. It also had
weak overall public services – education, health and other things – held back by a
pervasive weakness of government. By 1970 Philippines young males were a third
larger in number than their Philippine counterparts (1.7 to 1.4 million). Today (2000)
there are 4 million young male Filipinos against only 2.8 million Thais. Which
country bears greater costs of providing education and jobs? By 2025, Young
Filipino males will number 4.7 million against 2.7 million young Thais. The Philippines
is fostering a large cohort of young men who need schools and jobs to keep them in
society; without those amenities, this population will be vulnerable to leaders who
can use them for their own purposes, ostensibly through providing work and a sense
of belonging.
Wealth and Population
“Population growth, urban industrial society, economic development, environmental
degradation, and loss of biodiversity form a seamless web. Each is both the cause
and effect of the others. None can be effectively addressed in the absence of the
others” (IUCN 1997). We shall examine some relationships between population
measures and economic measures. These will demonstrate some surprisingly strong
relations, which should not be interpreted as simple cause-and-effect, but rather of
the interdependence of economic development and human population. But first, a
brief digression to define our economic measures.
Adam Smith changed how we think about the measurement of wealth. In his book,
“The Wealth of Nations” (1776), he argued that a country’s wealth lies not in its
gold, but in what it produces. This stimulated efforts to measure the output of a
country, leading to National Income Accounting and the idea of Gross National
Product. He also argued that reducing government restrictions and opening a
country to free trade would help make it wealthy.
The Gross National Product of a country is an estimate of the market value of all
the goods and services produced in a given period (usually a year).
The economy is circular: the price paid for a good or service goes to pay the factors
that produced it: Labor earns wages; capital earns interest; land earns rent; and
entrepreneurship earns profit. Thus we can add up all the earnings of the factors
of production, and that will (theoretically) equal the cost people pay for all the goods
and services produced.
Gross National or Gross Domestic Product?
For the most part, we shall treat them as interchangeable, but they are different,
and their differences can be used to examine certain aspects of an economy.
Gross National Product is the sum of all goods and services produced by
the factors of production owned by citizens of a nation.
Gross Domestic Product is the sum of all goods and services produced in
the territory of the nation, regardless of who owns the means of production
that generate the goods or services.
For example, if I invest some money in Mexico and it earns interest for me, it is a
part of the US GNP, since it is produced by US owned capital. But that interest is a
part of Mexico’s GDP, since it was produced in Mexican territory.
If a laborer comes from Mexico to work in the US, his earnings are part of the US
GDP, since they are produced here. But if he sends his earnings back to Mexico,
they are part of the Mexican GNP, since they are wages of a Mexican national.
We can compare countries using their GDP per capita (GDP/cap), and this will show
that there are many more poor countries than rich countries. Statistically, the
frequency distribution is skewed to the low end (think of a grade distribution skewed
toward very low grades but don’t worry, this won’t happen in our course). We often
use a log transformation of skewed data to better see the pattern, and so we will
graph the log (GDP/cap) against some population measures.
Consider the relationship between infant mortality rate and wealth. Wealth means
higher welfare, or lower infant mortality rates. When looking at such a graph,
always ask yourself: (1) what is the pattern here? (2) what might be the
explanation of outlying points. The deviant cases are those with higher or lower
IMR than expected given their level of economic development. Using a regression
line, the diagonal line across the chart, helps to see these clearly. A (linear)
regression line is the one straight line that is closest to all of the points on the chart.
Why are Mali and Sierra Leone higher than expected? Why are Cuba and Vietnam
lower than expected?
The quote just above stated that urbanization is intertwined as well. The next
graph documents that wealthy countries are more urbanized than poor
countries.
Here is another example: Wealthy countries are growing more slowly than
poorer countries. The problem of population growth is located in the poor
countries.
Wealthy countries are growing more slowly because they have lower fertility than
poor countries.
Wealthy countries have lower fertility because more of their people are
using contraceptives. But also look at the deviant cases. Why is Japan using
contraceptives less effectively than expected? Which other rich countries are using
fewer contraceptives than expected? How do you explain this? Which countries are
using more than expected? How do you explain this?
We close this lecture by emphasizing that the level of economic development of a
country is intimately related to the status of its human population. Furthermore,
Economic development has a very large impact on the global environment.
Keep the following ideas in the back of your mind for the rest of the semester.
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Rich countries produce, consume, and pollute far more than do poor
countries.
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high
The rapid population growth of the poor countries is overbalanced by the
individual consumption of the fewer people in the rich countries.
*
HOWEVER: Rich countries are becoming more efficient in energy use, and
are slowing the growth of consumption. Poor countries are increasing
energy consumption and CO2 emissions, and are often getting less efficient
in energy use.
SUMMARY
Human population rates have skyrocketed within the past two centuries and closely
correlate to economic growth and technological advancements. The past
demographic transition of the 1800's can be seen in many of today's developing
countries, however, population stabilization is occurring at a much slower rate. There
has been much concern on the implied socio and environmental impacts of these
population growth rates and their entailed consumption rates. Economic
measurements, such as GDP and GNP, are possible ways to assess these issues.
They can be used as proxies for indicating which nations are in need of the greatest
attention for mediation between the demands of a growing population and the
pressures put on their natural resources. However, there is much speculation as to
how accurate and relevant these measurements are.
Self-Test
Take the self-test for this lecture.
All materials © 2000 by the University of Michigan.