Demography and Population
LEARNING OBJECTIVES
By the end of this section, you will be able to:
Understand demographic measurements like fertility and mortality rates
Describe a variety of demographic theories, such as Malthusian, cornucopian, zero population
growth, and demographic transition theories
Be familiar with current population trends and patterns
Calculate the population using the exponential growth formula
Between 2011 and 2012, we reached a population milestone of 7 billion humans on the earth’s
surface. The rapidity with which this happened demonstrated an exponential increase from the time it
took to grow from 5 billion to 6 billion people. In short, the planet is filling up. How quickly will we go
from 7 billion to 8 billion? How will that population be distributed? Where is population the highest?
Where is it slowing down? Where will people live? To explore these questions, we turn
to demography, or the study of populations. Three of the most important components that affect the
issues above are fertility, mortality, and migration.
The fertility rate of a society is a measure noting the number of children born. The fertility
number is generally lower than the fecundity number, which measures the potential number of
children that could be born to women of childbearing age. Sociologists measure fertility using the
crude birthrate (the number of live births per 1,000 people per year). Just as fertility measures
childbearing, the mortality rate is a measure of the number of people who die. The crude death rate
is a number derived from the number of deaths per 1,000 people per year. When analyzed together,
fertility and mortality rates help researchers understand the overall growth occurring in a population.
Another key element in studying populations is the movement of people into and out of an area.
Migration may take the form of immigration, which describes movement into an area to take up
permanent residence, or emigration, which refers to movement out of an area to another place of
permanent residence. Migration might be voluntary (as when college students study abroad),
involuntary (as when Syrians evacuated war-torn areas), or forced (as when many Native American
tribes were removed from the lands they’d lived in for generations).
Population Growth
Changing fertility, mortality, and migration rates make up the total population composition, a
snapshot of the demographic profile of a population. This number can be measured for societies,
nations, world regions, or other groups. The population composition includes the sex ratio, the
number of men for every hundred women, as well as the population pyramid, a picture of population
distribution by sex and age.
This population pyramid shows the breakdown of the 2010 U.S. population according to age and sex.
(Graph courtesy of Econ Proph blog and the U.S. Census Bureau)
Varying Fertility and Mortality Rated by Country
Population (in Fertility Mortality Sex Ratio Male
Country
millions) Rate Rate to Female
Afghanistan 31.8 5.4% 14.1% 1.03
Sweden 9.7 1.9% 9.6% 0.98
United States of
318.92 2.0% 8.2% 0.97
America
As the table illustrates, countries vary greatly in fertility rates and mortality rates—the
components that make up a population composition. (Chart courtesy of CIA World
Factbook 2014)
Comparing the three countries in this table reveals that there are more men than women in
Afghanistan, whereas the reverse is true in Sweden and the United States. Afghanistan also has
significantly higher fertility and mortality rates than either of the other two countries. Do these
statistics surprise you? How do you think the population makeup affects the political climate and
economics of the different countries?
Demographic Theories
Sociologists have long looked at population issues as central to understanding human
interactions. Below we will look at four theories about population that inform sociological thought:
Malthusian, zero population growth, cornucopian, and demographic transition theories.
Malthusian Theory
Thomas Malthus (1766–1834) was an English clergyman who made dire predictions about
earth’s ability to sustain its growing population. According to Malthusian theory, three factors would
control human population that exceeded the earth’s carrying capacity, or how many people can live
in a given area considering the amount of available resources. Malthus identified these factors as
war, famine, and disease (Malthus 1798). He termed them “positive checks” because they increase
mortality rates, thus keeping the population in check. They are countered by “preventive checks,”
which also control the population but by reducing fertility rates; preventive checks include birth control
and celibacy. Thinking practically, Malthus saw that people could produce only so much food in a
given year, yet the population was increasing at an exponential rate. Eventually, he thought people
would run out of food and begin to starve. They would go to war over increasingly scarce resources
and reduce the population to a manageable level, and then the cycle would begin anew.
Of course, this has not exactly happened. The human population has continued to grow long
past Malthus’s predictions. So what happened? Why didn’t we die off? There are three reasons
sociologists believe we are continuing to expand the population of our planet. First, technological
increases in food production have increased both the amount and quality of calories we can produce
per person. Second, human ingenuity has developed new medicine to curtail death from disease.
Finally, the development and widespread use of contraception and other forms of family planning
have decreased the speed at which our population increases. But what about the future? Some still
believe Malthus was correct and that ample resources to support the earth’s population will soon run
out.
Zero Population Growth
A neo-Malthusian researcher named Paul Ehrlich brought Malthus’s predictions into the
twentieth century. However, according to Ehrlich, it is the environment, not specifically the food
supply, that will play a crucial role in the continued health of planet’s population (Ehrlich 1968).
Ehrlich’s ideas suggest that the human population is moving rapidly toward complete environmental
collapse, as privileged people use up or pollute a number of environmental resources such as water
and air. He advocated for a goal of zero population growth (ZPG), in which the number of people
entering a population through birth or immigration is equal to the number of people leaving it via death
or emigration. While support for this concept is mixed, it is still considered a possible solution to
global overpopulation.
Cornucopian Theory
Of course, some theories are less focused on the pessimistic hypothesis that the world’s
population will meet a detrimental challenge to sustaining itself. Cornucopian theory scoffs at the
idea of humans wiping themselves out; it asserts that human ingenuity can resolve any environmental
or social issues that develop. As an example, it points to the issue of food supply. If we need more
food, the theory contends, agricultural scientists will figure out how to grow it, as they have already
been doing for centuries. After all, in this perspective, human ingenuity has been up to the task for
thousands of years and there is no reason for that pattern not to continue (Simon 1981).
Demographic Transition Theory
Whether you believe that we are headed for environmental disaster and the end of human
existence as we know it, or you think people will always adapt to changing circumstances, we can
see clear patterns in population growth. Societies develop along a predictable continuum as they
evolve from unindustrialized to postindustrial. Demographic transition theory (Caldwell and
Caldwell 2006) suggests that future population growth will develop along a predictable four-stage
model.
In Stage 1, birth, death, and infant mortality rates are all high, while life expectancy is short. An
example of this stage is the 1800s in the United States. As countries begin to industrialize, they enter
Stage 2, where birthrates are higher while infant mortality and the death rates drop. Life expectancy
also increases. Afghanistan is currently in this stage. Stage 3 occurs once a society is thoroughly
industrialized; birthrates decline, while life expectancy continues to increase. Death rates continue to
decrease. Mexico’s population is at this stage. In the final phase, Stage 4, we see the postindustrial
era of a society. Birth and death rates are low, people are healthier and live longer, and society enters
a phase of population stability. Overall population may even decline. For example, Sweden is
considered to be in Stage 4.
The United Nations Population Fund (2008) categorizes nations as high fertility, intermediate
fertility, or low fertility. The United Nations (UN) anticipates the population growth will triple between
2011 and 2100 in high-fertility countries, which are currently concentrated in sub-Saharan Africa. For
countries with intermediate fertility rates (the United States, India, and Mexico all fall into this
category), growth is expected to be about 26 percent. And low-fertility countries like China, Australia,
and most of Europe will actually see population declines of approximately 20 percent. The graphs
below illustrate this trend.
Population Ecology
Population ecology is study of factors that influence:
1. Population size
a. increases - decreases
b. (Birth rate – death rate) + (immigration – emigration)
(B-d) + (i-e)
2. Population growth rate
Exponential Growth Rate Formula : A = Pert (review your MMW subject)
Where
e = 2.71828
A = future value
P = present value
r = rate of increase
t = number of years over which growth is to be measured
Example:
Project the world population in 2017 given the 1997 mid-year population of 5.85 billion
and a growth rate of 1.36% per year
A = Pert
A = (5.85 x 109) e(0.0136 x 20)
A = 7.679 x 109
The population in 2017 will be 7.679 billion
3. Density - # individuals per unit area (e.g., 1 duck per square meter, 100 oak trees per square
kilometer)
4. Population regulation
a. Carrying capacity – as above
b. Density dependent – population limiting factor that intensifies as density increases E.g.,
competition for food, nesting territory
Reflected by – decreased birth rate or increased death rate
c. Density independent – population limiting factor not related to density E.g., fire, fall
freeze, hurricane
Reflected by rapid death
5. Age structure - Proportion of individuals in different age groups (E.g., 10% population under 5
yrs old, 15% between 5-9, etc.)
Philippine Population as of 2020
The current population of the Philippines is 109,296,285 as of Wednesday, April 22, 2020,
based on Worldometer elaboration of the latest United Nations data.
The Philippines 2020 population is estimated at 109,581,078 people at mid-year according to
UN data.
The Philippines population is equivalent to 1.41% of the total world population.
The Philippines ranks number 13 in the list of countries (and dependencies) by population.
The population density in the Philippines is 368 per Km2 (952 people per mi2).
The total land area is 298,170 Km2 (115,124 sq. miles)
47.5 % of the population is urban (52,008,603 people in 2020)
The median age in the Philippines is 25.7 years.
ACTIVITY NO. 3 (LAST ACTIVITY FOR SEMI-FINALS)
1. Given what we know about population growth, what do you think of China’s policy that limits
the number of children a family can have? Do you agree with it? Why, or why not? What other
ways might a country of over 1.3 billion people manage its population?
2. Describe the effect of immigration or emigration on your life or in a community you have seen.
a. What are the positive effects?
b. What are the negative effects?
3. Discuss the positive and negative effects of the COVID-19 in the population of the Philippines
today and in the future?
4. The population of Henderson City was 3,381,000 in 1994, and is growing at an annual rate of
1.8%. If this growth continues, what will the approximate population of Henderson City be in the
year 2000?
