Chapter 2: Population
To understand the relationship between population and
resources in a country, geographers examine a country’s physiological and agricultural densities together. As shown in Table
2-1, the physiological densities of both Bangladesh and the
Netherlands are high, but the Dutch have a much lower agricultural density than the Bangladeshi. Geographers conclude
that both the Dutch and Bangladeshi put heavy pressure on the
land to produce food, but the Dutch agricultural system utilizes
fewer farmers than does the Bangladeshi system.
Similarly, the Netherlands has a much higher physiological
density than does India but a much lower agricultural density.
This difference demonstrates that, compared with India, the
Dutch have extremely limited arable land to meet the needs of
their population.
Recall from Chapter 1 how the Dutch have built dikes and
created polders, areas of land made usable by draining water
from them. The highly efficient Dutch farmers can generate a
large food supply from a limited resource.
KEY ISSUE 2
Where Has the World’s
Population Increased?
■
■
■
Natural Increase
Fertility
Mortality
After identifying where people are distributed across
Earth’s surface, we can describe the locations where the
numbers of people are increasing. Population increases
rapidly in places where many more people are born than
die, increases slowly in places where the number of births
exceeds the number of deaths by only a small margin,
and declines in places where deaths outnumber births.
The population of a place also increases when people
move in and decreases when people move out. This element of population change—migration—is discussed in
Chapter 3. ■
53
Natural Increase
Geographers most frequently measure population change in a
country or the world as a whole through three measures—
crude birth rate, crude death rate, and natural increase rate.
• Crude birth rate (CBR) is the total number of live births in
a year for every 1,000 people alive in the society. A CBR of
20 means that for every 1,000 people in a country, 20 babies
are born over a 1-year period.
Crude
death rate (CDR) is the total number of deaths in
•
a year for every 1,000 people alive in the society. Comparable to the CBR, the CDR is expressed as the annual number
of deaths per 1,000 population.
• Natural increase rate (NIR) is the percentage by which a
population grows in a year. It is computed by subtracting
CDR from CBR, after first converting the two measures from
numbers per 1,000 to percentages (numbers per 100). Thus
if the CBR is 20 and the CDR is 5 (both per 1,000), then the
NIR is 15 per 1,000, or 1.5 percent. The term natural means
that a country’s growth rate excludes migration.
The world NIR during the early twenty-first century has been
1.2, meaning that the population of the world had been growing
each year by 1.2 percent. The world NIR is lower today than its
all-time peak of 2.2 percent in 1963, and it has declined sharply
since the 1990s. However, the NIR during the second half of the
twentieth century was high by historical standards.
About 80 million people are being added to the population of
the world annually (Figure 2-8). That number represents a decline
from the historic high of 87 million in 1989. The number of people added each year has dropped much more slowly than the NIR
because the population base is much higher now than in the past.
World population increased from 3 to 4 billion in 14 years,
from 4 to 5 billion in 13 years, and from 5 to 6 billion in
12 years. As the base continues to grow in the twenty-first century, a change of only one-tenth of 1 percent can produce very
large swings in population growth.
The rate of natural increase affects the doubling time,
which is the number of years needed to double a population,
assuming a constant rate of natural increase. At the early
twenty-first-century rate of 1.2 percent per year, world population would double in about 54 years. Should the same NIR
continue through the twenty-first century, global population
World population (billions)
4
80
Annual increase (millions)
60
2
40
Natural increase rate (%)
20
1950
1960
1970
1980
1990
2000
2
1
2010
NIR
(%)
Population increase (million)
6
Population
(billion)
FIGURE 2-8 World population growth, 1950–2010.
100
The percentage by which the population grew (that is, the
natural increase rate [NIR]) declined during the late
twentieth century from its historic peak in the early
1960s, but the number of people added each year did not
decline very much, because with world population
increasing from 2.5 billion to nearly 7 billion people
during the period, the percentage was applied to an ever
larger base.
54
The Cultural Landscape
in the year 2100 would reach 24 billion. When the NIR was
2.2 percent back in 1963, doubling time was 35 years. Had the
2.2 percent rate continued into the twenty-first century,
Earth’s population in 2010 would be nearly 10 billion instead
of nearly 7 billion. A 2.2 percent NIR through the twenty-first
century would have produced a total population of more than
50 billion in 2100.
More than 95 percent of the natural increase is clustered in
LDCs (Figure 2-9). The NIR exceeds 2.0 percent in most countries of sub-Saharan Africa and the Middle East, whereas it is
negative in Europe, meaning that in the absence of immigrants,
population actually is declining. About one-third of the world’s
population growth during the past decade has been in South
Asia, one-fourth in sub-Saharan Africa, and the remainder
divided about equally among East Asia, Southeast Asia, Latin
America, and the Middle East.
Regional differences in NIRs mean that most of the world’s
additional people live in the countries that are least able to
maintain them. To explain these differences in growth rates,
geographers point to regional differences in fertility and mortality rates.
Fertility
The world map of crude birth rates (Figure 2-10) mirrors the
distribution of NIRs (compare with Figure 2-9). As was the
case with NIRs, the highest CBRs are in sub-Saharan Africa,
and the lowest are in Europe. Many
sub-Saharan African countries have a
CBR over 40, whereas many European
countries have a CBR below 10.
The word crude in crude birth rate
and
crude death rate means that we are
PACIFIC
concerned with society as a whole
ATLANTIC
OCEAN
OCEAN
rather than a refined look at particular
individuals or groups. In communities
PACIFIC
with an unusually large number of peoOCEAN
ple of a certain age—such as a college
INDIAN
OCEAN
town—we may study separate birth
rates for women of each age. These
NATURAL INCREASE
RATE (%)
numbers are age-specific birth rates
2.0 and above
rather than CBRs.
1.0–1.9
Geographers also use the total fer0.0–0.9
tility rate (TFR) to measure the numBelow 0
ber of births in a society (Figure 2-11).
The TFR is the average number of chilFIGURE 2-9 Natural increase rate (NIR). The natural increase rate is the percentage by which the
dren a woman will have throughout her
population of a country grows in a year. The world average is currently about 1.2 percent. The countries with
childbearing years (roughly ages 15
the highest natural increase rates are concentrated in Africa and Southwest Asia.
through 49). To compute the TFR,
demographers assume that a woman
reaching a particular age in the future
will be just as likely to have a child as
are women of that age today. Thus, the
CBR provides a picture of a society as a
whole in a given year, whereas the TFR
PACIFIC
ATLANTIC
OCEAN
attempts to predict the future behavior
OCEAN
of individual women in a world of rapid
cultural change.
PACIFIC
OCEAN
The TFR for the world as a whole is
2.6, and, again, the figures vary between
INDIAN
OCEAN
MDCs and LDCs. The TFR exceeds 6.0
in many countries of sub-Saharan
CRUDE BIRTH RATE
(PER 1,000 PERSONS)
Africa, compared to less than 1.9 in
35 and above
most European countries.
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Tropic of Capricorn
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0
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3,000 MILES
1,000 2,000 3,000 KILOMETERS
MODIFIED GOODE'S HOMOLOSINE EQUAL-AREA PROJECTION
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20–34
15–19
Below 10
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50°
0
0
1,000
2,000
180°
3,000 MILES
1,000 2,000 3,000 KILOMETERS
MODIFIED GOODE'S HOMOLOSINE EQUAL-AREA PROJECTION
FIGURE 2-10 Crude birth rate (CBR). The crude birth rate is the total number of live births in a year for
every 1,000 people alive in the society. The global distribution of crude birth rates parallels that of natural
increase rates.
Mortality
Two useful measures of mortality in
addition to the CDR already defined are
the infant mortality rate and life
55
Chapter 2: Population
expectancy. The infant mortality rate
(IMR) is the annual number of deaths of
infants under 1 year of age, compared
with total live births (Figure 2-12). As
PACIFIC
was the case with the CBR and CDR, the
ATLANTIC
OCEAN
OCEAN
IMR is usually expressed as the number
of deaths among infants per 1,000 births
PACIFIC
rather than as a percentage (per 100).
OCEAN
The global distribution of IMRs folINDIAN
OCEAN
lows the pattern that by now has become
familiar. The highest rates are in the
TOTAL WORLD
LDCs of sub-Saharan Africa, whereas the
FERTILITY RATE
lowest rates are in Europe. The IMR
4.0 and above
approaches 100 in sub-Saharan Africa,
3.0–3.9
meaning that nearly 10 percent of all
2.0–2.9
Below 2.0
babies in the region die before reaching
their first birthday. The IMR is less than
5 percent throughout Western Europe.
FIGURE 2-11 Total fertility rate (TFR). Total fertility rate is the number of children a woman will have
throughout her childbearing years. Again, the highest rates are in sub-Saharan Africa and the Middle East,
In general, the IMR reflects a country’s
whereas the lowest are in Europe.
health-care system. Lower IMRs are
found in countries with well-trained
doctors and nurses, modern hospitals,
and large supplies of medicine.
Although the United States is well
endowed with medical facilities, it suffers from a higher IMR than Canada
and every country in Western Europe.
PACIFIC
ATLANTIC
OCEAN
African Americans and other minoriOCEAN
ties in the United States have IMRs that
PACIFIC
are twice as high as the national averOCEAN
age, comparable to levels in Latin
America and Asia. Some health experts
INDIAN
OCEAN
attribute this to the fact that many
poor people in the United States, espeINFANT MORTALITY RATE
cially minorities, cannot afford good
(PER 1,000 LIVE BIRTHS)
health care for their infants.
60 and above
Life expectancy at birth measures the
20–59
average number of years a newborn
6–19
Below 6
infant can expect to live at current mortality levels (Figure 2-13). Like every
FIGURE 2-12 Infant mortality rate (IMR). The infant mortality rate is the number of deaths of infants
other mortality and fertility rate disunder age 1 per 1,000 live births in a year. European and North American countries generally have infant
cussed thus far, life expectancy is most
mortality rates of under 10 per 1,000, whereas rates of more than 100 per 1,000 are common in Africa
favorable in the wealthy countries of
Western Europe and least favorable in
world’s highest and lowest CDRs is much less extreme than
the poor countries of sub-Saharan Africa. Babies born today
the variation in CBRs. The highest CDR in the world is 23 per
can expect to live to around 80 in Western Europe but only to
1,000, and the lowest is 1—a difference of 22—whereas CBRs
around 50 in sub-Saharan Africa.
for individual countries range from 7 per 1,000 to 53, a spread
Natural increase, crude birth, total fertility, infant mortality,
of 46.
life expectancy—the descriptions have become repetitious
Why does Denmark, one of the world’s wealthiest counbecause their distributions follow similar patterns. MDCs have
tries, have a higher CDR than Cape Verde, one of the poorlower rates of natural increase, crude birth, total fertility, and
est? Why does the United States, with its extensive system of
infant mortality, and higher average life expectancy. Higher nathospitals and physicians, have a higher CDR than Mexico
ural increase, crude birth, total fertility rates, and IMRs and
and nearly every country in Latin America? The answer is
lower average life expectancy are found in LDCs.
that the populations of different countries are at various
The final world map of demographic variables—CDR—
stages in an important process known as the demographic
does not follow the familiar pattern (Figure 2-14). The comtransition, upon which we focus in the third key issue of this
bined CDR for all LDCs is actually lower than the combined
chapter.
rate for all MDCs. Furthermore, the variation between the
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3,000 MILES
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MODIFIED GOODE'S HOMOLOSINE EQUAL-AREA PROJECTION
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1,000 2,000 3,000 KILOMETERS
MODIFIED GOODE'S HOMOLOSINE EQUAL-AREA PROJECTION
56
The Cultural Landscape
FIGURE 2-13 Life expectancy at birth. Life
expectancy at birth is the average number of years a
newborn infant can expect to live. Worldwide, babies
born this year are expected to live until their mid-sixties.
Life expectancy for babies ranges from the 40s in several
African countries to the 80s in some MDCs.
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ATLANTIC
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LIFE EXPECTANCY
AT BIRTH (IN YEARS)
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80 and above
40°
70–79
50°
60–69
40°
40°
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110° 120° 130° 140° 150° 160°
50°
0
0
Below 60
FIGURE 2-14 Crude death rate (CDR). Crude death
rate is the total number of deaths in a year for every
1,000 people alive in the society. The global pattern of
crude death rates varies from those for the other
demographic variables already mapped in this chapter.
The demographic transition helps to explain the
distinctive distribution of crude death rates.
150°
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1,000 2,000 3,000 KILOMETERS
MODIFIED GOODE'S HOMOLOSINE EQUAL-AREA PROJECTION
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OCEAN
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10°
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SEA
PACIFIC
140°
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CRUDE DEATH RATE
(PER 1,000 PERSONS)
30°
20°
150°
OCEAN
20°
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15 and above
40°
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10–14
5–9
40°
110° 120° 130° 140° 150° 160°
50°
Why Is Population
Increasing at Different
Rates in Different
Countries?
■
■
■
■
The Demographic Transition
Population Pyramids
Countries in Different Stages of
Demographic Transition
Demographic Transition and World
Population Growth
All countries have experienced some changes in natural
increase, fertility, and mortality rates, but at different times
and at different rates. Although rates vary among countries,
0
0
Below 5
KEY ISSUE 3
40°
1,000
2,000
180°
3,000 MILES
1,000 2,000 3,000 KILOMETERS
MODIFIED GOODE'S HOMOLOSINE EQUAL-AREA PROJECTION
a similar process of change in a society’s population,
known as the demographic transition, is operating.
Because of diverse local cultural and economic conditions,
the demographic transition diffuses to individual countries
at different rates and produces local variations in natural
increase, fertility, and mortality. ■
The Demographic Transition
The demographic transition is a process with several stages,
and every country is in one of them. The process has a beginning, middle, and end. Historically, once a country has moved
from one stage of the process to the next, it has not reverted to
an earlier stage. However, a reversal may be occurring in some
African countries because of the AIDS epidemic. The four
stages are shown in Figure 2-15.
Stage 1: Low Growth
Most of humanity’s several-hundred-thousand-year occupancy
of Earth was characterized by stage 1 of the demographic transition. Crude birth and death rates varied considerably from