66
The Cultural Landscape
In contrast, the sudden drop in the CDR in Africa, Asia,
and Latin America in the twentieth century was accomplished by different means and with less internal effort by
local citizens. For example, the CDR on the island of Sri
Lanka (then known as Ceylon) plummeted 43 percent
between 1946 and 1947. The most important reason for the
sharp drop was the use of the insecticide DDT to control the
mosquitoes that spread malaria. European and North American countries invented and manufactured the DDT and
trained the experts to supervise its use. The spraying of Sri
Lankans’ houses and other medical services, which cost only
$2 per person per year, were paid for primarily by international organizations.
Thus Sri Lanka’s CDR was reduced by nearly one-half in a
single year with no change in the country’s economy or culture.
Medical technology was injected from Europe and North
America instead of arising within the country as part of an economic revolution. This pattern has been repeated throughout
Latin America, Asia, and Africa.
Having caused the first break with the past through diffusion of medical technology, European and North American
countries now urge other countries to complete the second
break with the past—the reduction in the birth rate. However,
reducing the CBR is more difficult. A decline in the CDR can be
induced through introduction of new technology by outsiders,
but the CBR will drop only when people decide for themselves
to have fewer children. Many LDCs, especially in Asia and
Latin America, have moved in recent years to stage 3 of the
demographic transition thanks to rapidly declining birth rates.
Other countries, especially in Africa, have not yet made this
second break with the past and in some cases may be slipping
back into stage 1.
In the past, stage 2 of the demographic transition lasted
for approximately 100 years in Europe and North America,
but today’s stage 2 countries are being asked to move through
to stage 3 in much less time in order to curtail population
growth. When European and North American countries
were in stage 2, the global population was increasing by
only about 6 million per year, compared to 80 million per
year now.
KEY ISSUE 4
Why Might the World
Face an Overpopulation
Problem?
■
■
■
Malthus On Overpopulation
Declining Birth Rates
World Health Threats
Why does global population growth matter? In view of
the current size of Earth’s population and the NIR, will
there soon be too many of us? Will continued population
growth lead to global starvation, war, and a lower quality
of life?
Geographers are particularly well suited to address
these questions because answers require understanding
both human behavior and the physical environment.
Further, geographers observe that diverse local cultural and
environmental conditions may produce different answers in
different places. ■
16
14
Population (billions)
Malthus on
Overpopulation
Population
Resources
12
10
8
6
4
2
0
2000
2025
2050
2075
2100
Year
FIGURE 2-25 Malthus’s theory. Malthus expected population to grow more rapidly than food production.
English economist Thomas Malthus
(1766–1834) was one of the first to
argue that the world’s rate of population
increase was far outrunning the development of food supplies. In An Essay on the
Principle of Population, published in
1798, Malthus claimed that the population was growing much more rapidly
than Earth’s food supply because population increased geometrically, whereas
food supply increased arithmetically
(Figure 2-25).
According to Malthus, these growth rates
would produce the following relationships
between people and food in the future:
Chapter 2: Population
•
•
•
•
•
Today:
25 years from now:
50 years from now:
75 years from now:
100 years from now:
1 person, 1 unit of food
2 persons, 2 units of food
4 persons, 3 units of food
8 persons, 4 units of food
16 persons, 5 units of food
Malthus made these conclusions several decades after England
had become the first country to enter stage 2 of the demographic transition, in association with the Industrial Revolution. He concluded that population growth would press against
available resources in every country, unless “moral restraint”
produced lower CBRs or unless disease, famine, war, or other
disasters produced higher CDRs.
Contemporary Neo-Malthusians
Malthus’s views remain influential today. Contemporary geographers and other analysts are taking another look at Malthus’s
theory because of Earth’s unprecedented rate of natural
increase during the late twentieth century.
Neo-Malthusians argue that two characteristics of recent population growth make Malthus’s thesis more frightening than
when it was first written more than 200 years ago.
1. First, in Malthus’s time only a few relatively wealthy countries had entered stage 2 of the demographic transition,
characterized by rapid population increase. Malthus failed
to anticipate that relatively poor countries would have the
most rapid population growth because of transfer of medical
technology (but not wealth) from MDCs. As a result, the
gap between population growth and resources is wider in
some countries than even Malthus
anticipated. Many LDCs have
expanded their food production
significantly in recent years, but
they have more poor people than
ever before.
2. The second argument made by
neo-Malthusians is that world
population growth is outstripping
a wide variety of resources, not just
food production (Figure 2-26).
Neo-Malthusians Robert Kaplan
and Thomas Fraser Homer-Dixon
paint a frightening picture of a
world in which billions of people
are engaged in a desperate search
for food and energy. They assert
that wars and civil violence will
increase in the coming years
because of scarcities of food as well
as such resources as clean air, suitable farmland, and fuel.
67
population growth and resource depletion sides of Malthus’s
equation.
Many geographers consider Malthusian beliefs unrealistically pessimistic because they are based on a belief that the
world’s supply of resources is fixed rather than expanding.
According to the principles of possibilism discussed in Chapter 1,
our well-being is influenced by conditions in the physical environment, but humans have some ability to choose courses of
action that can expand the supply of food and other resources.
A steady flow of new technology can offset scarcity of minerals
and arable land by using existing resources more efficiently and
substituting new resources for scarce ones.
Contemporary analysts such as Esther Boserup and Simon
Kuznets criticize Malthus’s theory that population growth produces problems. To the contrary, a larger population could
stimulate economic growth and, therefore, production of more
food. Population growth could generate more customers and
more ideas for improving technology.
Julian Simon argued that population growth stimulated economic growth. More people means more brains to invent good
ideas for improving life. Asked Simon, “Does anyone seriously
doubt that Europe is more prosperous with a population of
hundreds of millions than it would be with a population of
hundreds of thousands?”
Marxists maintain that no cause-and-effect relationship
exists between population growth and economic development.
Poverty, hunger, and other social welfare problems associated
with lack of economic development are a result of unjust social
and economic institutions, not population growth.
Malthus’s Critics
Malthus’s theory has been severely criticized from a variety of perspectives.
Criticism has been leveled at both the
FIGURE 2-26 Overpopulation in Mali. A region can be sparsely inhabited yet overpopulated if it has rapid
population growth and limited resources, as is the case in Mali.
68
The Cultural Landscape
Marxist theorist Friedrich Engels (1820–1895) dismissed
Malthus’s arithmetic as an artifact of capitalism. Engels argued
that the world possessed sufficient resources to eliminate
global hunger and poverty, if only these resources were shared
equally. Under capitalism, workers do not have enough food
because they do not control the production and distribution of
food and are not paid sufficient wages to purchase it.
The world is much better off economically with 7 billion people than it was with 1 billion, argue Malthus’s critics, because too
few people can retard economic development as surely as can too
many people. A large population of consumers can generate a
greater demand for goods, which results in more jobs.
Some political leaders, especially in Africa, argue that high
population growth is good for a country because more people
will result in greater power. Population growth is desired in
order to increase the supply of young men who could serve in
the armed forces. On the other side of the coin, more developed countries are viewed as pushing for lower population
growth as a means of preventing further expansion in the percentage of the world’s population living in poorer countries.
twice as fast as Malthus expected (Figure 2-27). Better growing
techniques, higher-yielding seeds, and cultivation of more land
have contributed to the expansion in food supply (see Chapter
10). Many people in the world cannot afford to buy food or do
not have access to sources of food, but these are problems of
distribution of wealth rather than insufficient global production of food, as Malthus theorized.
It is on the population side of the equation, though, that
Malthus has proved to be inaccurate. His model expected population to quadruple during a half-century, but even in India—
a country known for relatively rapid growth (see Case Study
Revisited at the end of this chapter)—population has increased
more slowly than food supply.
However, neo-Malthusians point out that production of
both wheat and rice has slowed in India in recent years, as
shown in Figure 2-27. Without new breakthroughs in food production, India will not be able to keep food supply ahead of
population growth.
Declining Birth Rates
On a global scale, conditions during the past half-century have
not supported Malthus’s theory. Even though the human population has grown at its most rapid rate ever, world food production has consistently grown at a faster rate than the NIR since
1950, according to geographer Vaclav Smil, Distinguished Professor at the University of Manitoba. Smil has shown that
Malthus was fairly close to the mark on food production but
much too pessimistic on population growth.
Overall food production has increased during the last halfcentury somewhat more rapidly than Malthus predicted. In
India, for example, rice production has followed Malthus’s
expectations fairly closely, but wheat production has increased
100
Rice
Production (metric tons)
80
Wheat
60
The Malthus theory seems unduly pessimistic on a global scale,
but geographers recognize the diversity of conditions among
regions of the world. Although the world as a whole may not be
in danger of “running out” of food, some regions with rapid
population growth do face shortages of food.
The NIR can decline for only two reasons—lower birth rates
or higher death rates. Few people wish to see the NIR decline
because of an increase in death rates. The only demographic
alternative is to reduce birth rates. In most countries, the decline
in the NIR has occurred because of a lower birth rate, but in
some countries of sub-Saharan Africa, the CDR is increasing.
The CBR has declined rapidly since 1990 from 27 to 21 in
the world as a whole and from 31 to 23 in LDCs. A substantial decline in the birth rate has been recorded
since 1990 by nearly every country in Asia,
Latin America, and the Middle East, as well as
selected countries in sub-Saharan Africa
(Figure 2-28).
Two strategies have been successful in reducing birth rates. One alternative emphasizes
reliance on economic development, the other on
1.2
distribution of contraceptives. Because of varied
economic and cultural conditions, the most
1.0
effective method varies among countries.
0.8
40
Population
0.6
20
0.4
Population (billions)
Malthus’s Theory and Reality
0.2
0
1960
1970
1980
1990
2000
2008
Year
FIGURE 2-27 Population and food production in India. Production of wheat and rice has
increased at a more rapid rate than has population.
Reasons for Declining Birth
Rates
One approach to lowering birth rates emphasizes the importance of improving local economic conditions. A wealthier community has
more money to spend on education and healthcare programs that would promote lower birth
rates. According to this approach, if more
women are able to attend school and to remain
in school longer, they are more likely to learn
69
Chapter 2: Population
80°
ARCTIC OCEAN
ARCTIC OCEAN
70°
Arctic Circle
60°
60°
50°
50°
50°
50°
PACIFIC
40°
40°
ATLANTIC
OCEAN
30°
40°
40°
OCEAN
30°
30°
30°
Tropic of Cancer
20°
20°
160°
PACIFIC
10°
OCEAN
0°
Tropic of Cancer
20°
ARABIAN
SEA
BAY OF
BENGAL
10°
10°
Equator
50°
0°
60°
70°
80°
INDIAN
10°
20°
30°
10°
CBR DECLINE
1980–2009
140°
90°
10°
120°
20°
150°
OCEAN
20°
150°
160°
170°
CORAL SEA
20°
20°
20°
15 and above
10–14
30°
30°
40°
40°
50°
50°
Tropic of Capricorn
30°
30°
30°
5–9
40°
Below 5
40°
40°
110° 120° 130° 140° 150° 160°
No data
50°
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 2-28 Crude birth rate change, 1980–2008. The crude birth rate has declined in all but a handful of
countries. Declines have been most rapid in the Middle East, Latin America, and South Asia. Still, the number
of births in the world increased during the three decades from about 120 million to 140 million per year.
employment skills and gain more economic control over their
lives. With better education, women would better understand
their reproductive rights, make more informed reproductive
choices, and select more effective methods of contraception.
With improved health-care programs, IMRs would decline
through such programs as improved prenatal care, counseling
about sexually transmitted diseases, and child immunization.
With the survival of more infants ensured, women would be
more likely to choose to make more effective use of contraceptives to limit the number of children.
Reducing Births Through
Contraception
The other approach to lowering birth rates emphasizes the
importance of rapidly diffusing modern contraceptive methods
(Figure 2-29). Economic development may promote lower
birth rates in the long run, but the world cannot wait around
for that alternative to take effect. Putting resources into familyplanning programs can reduce birth rates much more rapidly.
In LDCs, demand for contraceptive devices is greater than the
available supply. Therefore, the most effective way to increase
their use is to distribute more of them, cheaply and quickly.
According to this approach, contraceptives are the best method
for lowering the birth rate.
Bangladesh is an example of a country that has had little
improvement in the wealth and literacy of its people, but 56
percent of the women in the country used contraceptives in
2009 compared to 6 percent three decades earlier. Similar
growth in the use of contraceptives has occurred in other
FIGURE 2-29 Promoting contraceptives in India. An inflatable vending machine
promotes use of condoms in India.
70
The Cultural Landscape
LDCs, including Colombia, Morocco, and Thailand. Rapid
growth in the acceptance of family planning is evidence that in
the modern world, ideas can diffuse rapidly, even to places
where people have limited access to education and modern
communications.
The percentage of women using contraceptives is especially
low in sub-Saharan Africa, so the alternative of distributing
contraceptives could have an especially strong impact there.
Less than one-fourth of women in sub-Saharan Africa employ
contraceptives, compared to more than two-thirds in Asia and
in Latin America (Figure 2-30).
Methods of family planning also vary among countries. The
reason for this is partly economics, religion, and education.
Very high birth rates in Africa and southwestern Asia also
reflect the relatively low status of women. In societies where
women receive less formal education and hold fewer legal
rights than do men, women regard having a large number of
children as a measure of their high status, and men regard it as
a sign of their own virility.
Regardless of which alternative is more successful, many
oppose birth-control programs for religious and political reasons. Adherents of several religions, including Roman
Catholics, fundamentalist Protestants, Muslims, and Hindus,
have religious convictions that prevent them from using some
or all birth-control devices. Opposition is strong within the
United States to terminating pregnancy by abortion, and the
U.S. government has at times withheld aid to countries and
family-planning organizations that advise abortion, even when
such advice is only a small part of the overall aid program.
Analysts agree that the most effective means of reducing
births would employ both alternatives. But LDC governments
and international family-planning organizations have limited
funds to promote lower birth rates, so they must set priorities
and make choices for allocating scarce funds.
80°
ARCTIC OCEAN
ARCTIC OCEAN
70°
Arctic Circle
60°
60°
50°
50°
50°
50°
PACIFIC
40°
40°
ATLANTIC
OCEAN
30°
40°
40°
OCEAN
30°
30°
30°
Tropic of Cancer
Tropic of Cancer
20°
20°
160°
PACIFIC
10°
OCEAN
BAY OF
BENGAL
10°
10°
Equator
0°
20°
ARABIAN
SEA
50°
0°
60°
70°
80°
INDIAN
10°
10°
140°
90°
OCEAN
10°
120°
WOMAN USING
FAMILY PLANNING (%)
20°
20°
75 above
30°
20°
30°
30°
40°
40°
50°
50°
150°
150°
20°
Tropic of Capricorn
30°
160°
170°
CORAL SEA
20°
20°
30°
30°
50–74
25–49
40°
40°
40°
Below 25
110° 120° 130° 140° 150° 160°
No data
50°
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
2%
2% 2%
1%
FAMILY PLANNING METHOD
Pill
IUD
8%
Condom
Female sterilization
Male sterilization
Periodic abstinence and withdrawal
6%
16%
1%
25%
2%
1%
3%
36%
59%
4%
6%
85%
34%
Other
3%
Not using a method
GERMANY
CHINA
FIGURE 2-30 Family planning. More than two-thirds of couples in MDCs use a family-planning method, primarily condoms or birth-control pills. Family-planning practices vary more widely in other regions. China reports
the world’s highest rate of family planning, primarily with the use of intrauterine devices (IUDs) and female sterilization. The lowest rates are in countries of sub-Saharan Africa, such as Nigeria.
NIGERIA
4%
Chapter 2: Population
World Health Threats
Lower CBRs have been responsible for declining NIRs in most
countries. However, in some countries of sub-Saharan Africa,
lower NIRs have also resulted from higher CDRs, especially
through the diffusion of AIDS.
Medical researchers have identified an epidemiologic transition that focuses on distinctive causes of death in each stage of the
demographic transition. The term epidemiologic transition comes
from epidemiology, which is the branch of medical science concerned with the incidence, distribution, and control of diseases
that are prevalent among a population at a special time and are
produced by some special causes not generally present in the
affected locality. Epidemiologists rely heavily on geographic concepts such as scale and connection because measures to control
and prevent an epidemic derive from understanding its distinctive
distribution and method of diffusion.
Epidemiologic Transition
Stages 1 and 2
Stage 1 of the epidemiologic transition, as originally formulated by epidemiologist Abdel Omran in 1971, has been called
the stage of pestilence and famine. Infectious and parasitic
diseases were principal causes of human deaths, along with
accidents and attacks by animals and other humans. Malthus
called these causes of deaths “natural checks” on the growth of
the human population in stage 1 of the demographic transition.
crowded into rapidly growing industrial cities had especially high
death rates. Cholera—uncommon in rural areas—became an
especially virulent epidemic in urban areas during the Industrial
Revolution. A half-million people died of cholera in New York
City in 1832, and one-eighth of the population of Cairo in 1831.
Geographic methods played a key role in understanding the
cause of cholera during the early nineteenth century. The
Report of Sanitary Condition of the Labouring Population of Great
Britain, written in 1842 by Edwin Chadwick (1800–1890),
showed that residents of poorer neighborhoods had a much
higher incidence of cholera and other diseases and died at a
younger age. Dr. John Snow (1813–1858) mapped the distribution of deaths from cholera in 1854 in the poor London neighborhood of Soho (Figure 2-31).
Many in the nineteenth century believed that epidemic victims were being punished for sinful behavior and that most
victims were poor because poverty was considered a sin. Dr.
Snow, however, showed that cholera was not distributed uniformly among the poor. Predating GIS by more than a century,
he overlaid a map of the distribution of cholera victims with a
map of the distribution of water pumps—for poor people the
source of water for drinking, cleaning, and cooking.
Dr. Snow found that a large percentage of cholera victims were
clustered around one pump, on Broad Street (refer to Figure 2-31).
Tests proved that the water at the Broad Street pump was contaminated, and further investigation revealed that contaminated
sewage was getting into the water supply near the pump.
Construction of water and sewer systems eradicated cholera
by the late nineteenth century. However, cholera reappeared a
century later in rapidly growing cities of LDCs as they moved
into stage 2 of the demographic transition.
Water pump
Cholera victim
ET
STRE
D
DE
OXFOR
AN
ET
RE
T
E
RE
ET
EE
TR
ST
RE
RS
ICK
RW
T
ST
NG
ST
RE
ET
ON
GT
XIN
LE
KI
D
OA
BR
ST
BE
OU
RD
WA
ET
RE
ST
GH
OU
OR
LB
AR
.M
GT
NT
GE
RE
ET
RE
ST
EN
LD
GO Q.
S
RW
WA
K
IC
ET
RE
ST
EW
BR
ER
ST
E
RE
T
ET
W
RO
RE
ST
LE
VIL
SA
BLACK PLAGUE. Well documented is the origin and diffusion of history’s most violent stage 1 epidemic—the Black
Plague, or bubonic plague, which was probably transmitted to
humans by fleas from migrating infected rats. The Black Plague
originated in present-day Kyrgyzstan and was brought from
there by a Tatar army when it attacked an Italian trading post
on the Black Sea in present-day Ukraine. Italians fleeing the
trading post then carried the infected rats on ships west to the
major coastal cities of southeastern Europe in 1347.
The plague spread from the coast to inland towns and then
to rural areas. The plague reached Western Europe in 1348 and
northern Europe in 1349. About 25 million Europeans died
between 1347 and 1350, at least one-half of the continent’s
population. Five other epidemics in the late fourteenth century
added to the toll in Europe. In China, 13 million died from the
plague in 1380.
The plague wiped out entire villages and families, leaving
farms with no workers and estates with no heirs. Churches
were left without priests and parishioners, schools without
teachers and students. Ships drifted aimlessly at sea after entire
crews succumbed to the plague.
Stage 2 of the epidemiologic transition has been called the
stage of receding pandemics. A pandemic is disease that occurs
over a wide geographic area and affects a very high proportion
of the population. Improved sanitation, nutrition, and medicine during the Industrial Revolution reduced the spread of
infectious diseases.
Death rates did not decline immediately and universally during the early years of the Industrial Revolution. Poor people
71
FIGURE 2-31 Cholera in Soho, London, 1854. Dr. John Snow mapped the
distribution of cholera victims and water pumps to prove that the cause of the infection
was contamination of the pump near the corner of Broad and Lexington streets.
72
The Cultural Landscape
Epidemiologic Transition
Stages 3 and 4
Epidemiologic Transition Possible
Stage 5
Stage 3 of the epidemiologic transition, the stage of degenerative and human-created diseases, is characterized by a decrease
in deaths from infectious diseases and an increase in chronic
disorders associated with aging. The two especially important
chronic disorders in stage 3 are cardiovascular diseases, such as
heart attacks, and various forms of cancer.
The decline in infectious diseases has been sharp in stage 3
countries. Cases of polio declined in the United States from
14,000 in 1954 to 167 in 1965, 20 in 1975, and 0 in the entire
Western Hemisphere during the 1990s. Worldwide polio cases
declined from 39,000 in 1985 to 6,000 in 1994. The number of
measles cases per year declined in the United States from
760,000 in 1958 to 2,000 during the 1980s and 1,000 during
the 1990s. Fatalities from measles for children under age 15
declined in England from 110 per 100,000 during the nineteenth century to 10 during the 1940s and none during the
1960s. Effective vaccines were responsible for these declines.
As LDCs moved recently from stage 2 to stage 3, infectious
diseases also declined. The number of cases of polio, neonatal
tetanus, diphtheria, and pertussis declined by more than threefourths in Southeast Asia between 1988 and 1994. The number
of cases of leprosy declined from 483,000 in 1990 to 159,000 in
1993 in Africa.
Omran’s epidemiologic transition was extended by S. Jay
Olshansky and Brian Ault to stage 4, the stage of delayed degenerative diseases. The major degenerative causes of death—
cardiovascular diseases and cancers—linger, but the life expectancy
of older people is extended through medical advances. Through
medicine, cancers spread more slowly or are removed altogether.
Operations such as bypasses repair deficiencies in the cardiovascular system. Also improving health are behavior changes such as
better diet, reduced use of tobacco and alcohol, and exercise.
Some medical analysts argue that the world is moving into
stage 5 of the epidemiologic transition, the stage of reemergence of infectious and parasitic diseases. Infectious diseases
thought to have been eradicated or controlled have returned,
and new ones have emerged. A consequence of stage 5 would
be higher CDRs. Other epidemiologists dismiss recent trends as
a temporary setback in a long process of controlling infectious
diseases.
Three reasons help to explain the possible emergence of a
stage 5 of the epidemiologic transition:
80°
ARCTIC OCEAN
ARCTIC OCEAN
70°
Arctic Circle
60°
60°
50°
50°
50°
40°
40°
40°
30°
Tropic of Cancer
30°
ATLANTIC
OCEAN
30°
PACIFIC
OCEAN
0°
50°
40°
30°
Tropic of Cancer
20°
20°
160°
10°
30°
20°
ARABIAN
SEA
BAY OF
BENGAL
10°
10°
50°
60°
Equator
0°
Equator
70°
80°
INDIAN
10°
10°
20°
1. Evolution. Infectious disease microbes have continuously
evolved and changed in response to environmental pressures by developing resistance to drugs and insecticides.
Antibiotics and genetic engineering contribute to the
emergence of new strains of viruses and bacteria.
Malaria was nearly eradicated in the mid-twentieth
century by spraying DDT in areas infested with the mosquito that carried the parasite. For example, new malaria
cases in Sri Lanka fell from 1 million in 1955 to 18 in
1963. The disease returned after 1963, however, and
now causes more than 1 million deaths worldwide annually. A major reason was the evolution of DDT-resistant
mosquitoes.
2. Poverty. Tuberculosis (TB) is an example of an infectious disease that has been largely controlled in relatively developed countries like the United States but
remains a major cause of death in LDCs (Figure 2-32).
An airborne disease, TB spreads principally through
coughing and sneezing, damaging lungs.
TB was one of the principal causes of death among
the urban poor in the nineteenth century during the
Industrial Revolution. The death rate
from TB declined in the United States
from 200 per 100,000 in 1900 to 60 in
1940 and 4 today. However, in LDCs,
the TB rate is more than ten times
higher than in MDCs, and nearly 2 milPACIFIC
lion worldwide die from it annually. TB
OCEAN
is more prevalent in poor areas because
the long, expensive treatment poses a
significant economic burden. Patients
stop taking the drugs before the treatment cycle is completed.
3. Improved travel. A pandemic is a
disease that occurs over a wide geographic area and affects an exceptionally high proportion of the population.
Motor vehicles allow rural residents to
easily reach urban areas and urban residents to reach rural areas. Airplanes
allow residents of one country to easily reach another. As they travel, peoindicator of a country’s
ple carry diseases with them and are
exposed to the diseases of others.
140°
90°
OCEAN
10°
120°
TUBERCULOSIS
DEATH RATE
PER 100,000
20°
20°
30°
30°
20°
Tropic of Capricorn
40°
50 above
40°
40°
50°
10–49
50°
50°
30°
40°
150°
160°
3–9
40°
0
0
20°
30°
30°
110° 120° 130° 140° 150° 160°
50°
170°
CORAL SEA
20°
150°
1,000
2,000
180°
3,000 MILES
1,000 2,000 3,000 KILOMETERS
MODIFIED GOODE'S HOMOLOSINE EQUAL-AREA PROJECTION
Below 3
No data
FIGURE 2-32 Tuberculosis (TB) cases, 2009. Death from tuberculosis is a good
ability to invest in health care, because treating the disease is expensive.
73
Chapter 2: Population
80°
ARCTIC OCEAN
ARCTIC OCEAN
70°
Arctic Circle
60°
60°
50°
50°
50°
50°
PACIFIC
40°
40°
ATLANTIC
OCEAN
30°
40°
40°
OCEAN
30°
30°
30°
Tropic of Cancer
20°
20°
160°
PACIFIC
10°
OCEAN
0°
Tropic of Cancer
20°
ARABIAN
SEA
BAY OF
BENGAL
10°
10°
Equator
50°
0°
60°
70°
80°
INDIAN
10°
20°
30°
HIV/AIDS
ADULT PREVALENCE
PER 1,000
100 and above
10–99
10°
140°
90°
10°
120°
20°
20°
30°
30°
40°
40°
50°
50°
150°
OCEAN
150°
Tropic of Capricorn
30°
160°
170°
CORAL SEA
20°
20°
20°
30°
30°
3–9
40°
Below 3
40°
40°
No data
50°
110° 120° 130° 140° 150° 160°
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 2-33 HIV/AIDS, 2007. The highest rates of HIV infection are in sub-Saharan Africa. India and China
have relatively high numbers of HIV-positive adults, but they constitute a lower percentage of the total population.
Several dozen “new” infectious diseases have emerged over
the past three decades and have spread through travel. Most
prominent currently is H1N1, commonly known as swine flu,
which was first identified in Mexico in early 2009 and spread
around the world very rapidly.
The Bio.Diaspora Project, based at St. Michael’s Hospital in
Toronto, matched the global diffusion of H1N1 to airline travel
patterns. The number of passengers arriving by air from Mexico was a strong predictor of the number of H1N1 cases in a
particular city or country.
AIDS. The most lethal epidemic in recent years has been
AIDS (acquired immunodeficiency syndrome). Worldwide,
25 million people died of AIDS as of 2007, and 33 million were
living with HIV (human immunodeficiency virus, the cause of
AIDS). The distribution of AIDS within the United States
was discussed in Chapter 1 (see Figure 1-22), but 90 percent
of people living with HIV come from LDCs. There were
22 million people infected with HIV in sub-Saharan Africa in
2007, 5 million in Asia, 2 million each in Eastern Europe and
Latin America, and 1 million each in North America and
Western Europe (Figure 2-33).
The impact of AIDS has been felt most strongly in subSaharan Africa. With one-tenth of the world’s population,
sub-Saharan Africa had two-thirds of the world’s total HIVpositive population and nine-tenths of the world’s infected
children. South Africa had the most cases, 6 million, and
Botswana, Lesotho, and Swaziland had the highest rates of
infection—one-fourth of the three countries’ adults were HIVpositive.
CDRs in many sub-Saharan Africa countries rose sharply
during the 1990s as a result of AIDS, from the mid-teens to the
low twenties. The populations of Lesotho and Swaziland are
forecast to decline between now and 2050 as a result of AIDS.
Life expectancy has declined in these two countries, from the
50s during the 1980s to the 40s currently.
SUMMARY
Overpopulation—too many people for the available resources—has
already hit regions of Africa and threatens other countries in Asia and
Latin America. The world as a whole does not face overpopulation immediately, but current trends must be reversed to prevent a future crisis.
Geographers caution that the number of people living in a region is
not by itself an indication of overpopulation. Some densely populated
regions are not overpopulated, whereas some sparsely inhabited areas
are. Instead, overpopulation is a relationship between the size of the
population and a region’s level of resources. The capacity of the land
to support life derives partly from characteristics of the natural environment and partly from human actions to modify the environment
through agriculture, industry, and exploitation of raw materials.
The track toward overpopulation already may be irreversible in Africa.
Rapid population growth has led to the overuse of land. As the land
declines in quality, more effort is needed to yield the same amount of
crops. This extends the working day of women, who have the primary