Population Chapter Two

Chapter Two
Population
Distribution of World Population
• Population concentrations
– The four largest population clusters [East Asia, South Asia,
Southeast Asia, Western Europe]
– Other population clusters [W. Hemisphere, West Africa]
• Sparsely populated regions
• Dry lands – 20% to dry to farm; contain natural resources?
• Wet lands – near equator b/t 20° north & south latitude;
large amounts of rainfall
• Cold lands – covered with ice or permafrost; unsuitable
• High lands – mountains are steep, snow covered
World Population Cartogram
Fig. 2-1: This cartogram displays countries by the size of their population rather than
their land area. (Only countries with 50 million or more people are named.)
World
Population
Distribution
& Climate
Zones
Fig. 2-2: World population is unevenly distributed across the earth’s surface.
Climate is one factor that affects population density.
Expansion
of the
Ecumene
5000 BC AD 1900
Fig. 2-3: The ecumene, or
the portion of the
earth with
permanent human
settlement, has
expanded to cover
most of the world’s
land area.
Ecumene, 5000 B.C.
Ecumene, A.D. 1
Ecumene, A.D.1500
Ecumene, A.D.1900
Population Density
Arithmetic
 total # of people divided by total land area
 Answers the “where” question
Physiological
 # of people supported by a unit area of arable land
 Provides insights into the relationship b/t size of
population & availability of resources in a region
Agricultural
 Ratio of the # of farmers to the amount of arable land
 This measure helps account for economic differences
(MDCs vs. LDCs)
Arithmetic Population Density
Fig. 2-4: Arithmetic population density is the number of people per total land area.
The highest densities are found in parts of Asia and Europe.
Physiological Density
Fig. 2-5: Physiological density is the number of people per arable land area. This
is a good measure of the relation between population and agricultural
resources in a society.
Measures of Population Density
Distribution of World Population Growth
 Natural Increase
 Crude Birth Rate (CBR) – total # of live births per year for
every 1,000 people alive
 Crude Death Rate (CDR) – total # of deaths per year for
every 1,000 people alive
 Natural Increase Rate (NIR) - % by which population grows
in a year [(CBR-CDR)/10 = NIR]
 High base population means small changes in NIR have dramatic
effect
 Doubling Time - # of years needed to double population
assuming constant rate of natural increase
 Virtually 100% of natural increase clustered in LDCs
Distribution of World Population Growth
 Fertility
 Total Fertility Rate – average number of children a woman
will have throughout her child-bearing years
 Vary between LDCs & MDCS
 2.7 for world as whole
 Mortality
 Infant Mortality Rate – annual # of deaths of infants
compared w/ total live births
 Higher rates in poorer countries; reflects country’s healthcare system
 Life expectancy – measures the average # of years a
newborn infant can expect to live at current mortality levels
World Population Growth
1950 - 2005
Fig. 2-6: Total world population increased from 2.5 to over 6 billion in slightly over 50
years. The natural increase rate peaked in the early 1960s and has declined
since, but the number of people added each year did not peak until 1990.
Natural Increase Rates
Fig. 2-7: The natural increase rate (NIR) is the percentage growth or decline in the
population of a country per year (not including net migration). Countries in
Africa and Southwest Asia have the highest current rates, while Russia and
some European countries have negative rates.
Crude Birth Rates
Fig. 2-8: The crude birth rate (CBR) is the total number of births in a country per 1000
population per year. The lowest rates are in Europe, and the highest rates are in
Africa and several Asian countries.
Total Fertility Rates
Fig. 2-9: The Total fertility rate (TFR) is the number of children an average woman in a
society will have through her childbearing years. The lowest rates are in Europe,
and the highest are in Africa and parts of the Middle East.
Infant Mortality Rates
Fig. 2-10: The infant mortality rate is the number of infant deaths per 1000 live births per
year. The highest infant mortality rates are found in some of the poorest
countries of Africa and Asia.
Life Expectancy at birth
Fig. 2-11: Life expectancy at birth is the average number of years a newborn infant can
expect to live. The highest life expectancies are generally in the wealthiest
countries, and the lowest in the poorest countries.
Crude Death Rates
Fig. 2-12: The crude death rate (CDR) is the total number of deaths in a country per
1000 population per year. Because wealthy countries are in a late stage of
the Demographic Transition, they often have a higher CDR than poorer
countries.
Variations in Population Growth
• The Demographic Transition [4 stages]
1. Low growth

agricultural revolution allowed for more people to survive
2. High growth



Industrial revolution spurs movement into stage
CDR decreasing, CBR stable
Medical revolution pushed LDCs into stage in late 20th century
3. Moderate growth


CBR begins to drop, still higher than CDR
People decide to have fewer offspring => decline in mortality & IMR;
economic changes (work in cities)
4. Low growth

CBR = CDR & NIR nears zero (0) => Zero population growth
Variations in Population Growth
• Population pyramids
 Age distribution
 Dependency ratio – larger the % of dependents, the greater
the financial burden on those working
 Sex ratio
 # of males per 100 females; slightly more males born, but have
higher death rates
• Countries in different stages of demographic transition
• Demographic transition and world population growth
The Demographic Transition
Fig. 2-13: The demographic transition consists of four stages, which move from high
birth and death rates, to declines first in death rates then in birth rates, and
finally to a stage of low birth and death rates. Population growth is most
rapid in the second stage.
World Population & Growth
Rates, 400,000 BC - AD 2000
Demographic Transition in England
Fig. 2-14: England was one of the first countries to experience rapid population growth in
the mid-eighteenth century, when it entered stage 2 of the demographic
transition.
Percent of Population under 15
Fig. 2-15: About one-third of world population is under 15, but the percentage by country
varies from over 40% in most of Africa and some Asian countries, to under 20%
in much of Europe.
Population Pyramids in U.S. cities
Fig. 2-16: Population pyramids can vary greatly with different fertility rates (Laredo vs.
Honolulu), or among military bases (Unalaska), college towns (Lawrence), and
retirement communities (Naples).
Rapid Growth in Cape Verde
Fig. 2-17: Cape Verde, which entered stage 2 of the demographic transition in about
1950, is experiencing rapid population growth. Its population history
reflects the impacts of famines and out-migration.
Moderate Growth in Chile
Fig. 2-18: Chile entered stage 2 of the demographic transition in the 1930s, and it
entered stage 3 in the 1960s.
Low Growth in Denmark
Fig. 2-19: Denmark has been in stage 4 of the demographic transition since the
1970s, with little population growth since then. Its population
pyramid shows increasing numbers of elderly and few children.
Will the World Face an
Overpopulation Problem?
Thomas Malthus
 Argued world’s rate of population increase was far outrunning
development of food supplies
 Population increased geometrically, whereas food supply
increased arithmetically
Neo-Malthusians
Medical technology resulted in gap b/t population
growth & resources widening in some countries
World pop. Outstripping variety of resources which
will lead to war & civil violence
Overpopulation Problem
• Critics of Malthus
– Possibilists, Contemporary analysts, Marxists,
Economic, Political leaders
• Declining birth rates
– Malthus theory & reality
• Food production increased more rapidly
• Population increased at a slower rate; NIR declined
– Reasons for declining birth rates
• Economic development
• Distribution of contraceptives
World Health Threats
• Epidemiological Transition – focuses on
distinctive cause of death in each stage of
demographic transition
• Stage 1 – pestilence & famine; Black Plague
• Stage 2 – receding pandemics; Cholera
• Stage 3 – degenerative & human-created
diseases; cardiovascular disease, cancer
• Stage 4 – delayed degenerative diseases
• Stage 5 – reemergence of infectious &
parasitic diseases
Food &
Population,
1950-2000
Malthus vs.
Actual Trends
Fig. 2-20: Malthus predicted population would grow faster than food production,
but food production actually expanded faster than population in the
2nd half of the 20th century.
Crude Birth Rate Decline, 1980-2005
Fig. 2-21: Crude birth rates declined in most countries during the 1980s and 1990s
(though the absolute number of births per year increased from about 120 to
130 million).
Use of Family Planning
Fig. 2-22: Both the extent of family planning use and the methods used vary widely by
country and culture.
Women Using Family Planning
Family Planning Methods
used in three countries
Promoting One-Child Policy in China
Cholera
in
London,
1854
Fig. 2-23: By mapping the distribution of cholera cases and water pumps in Soho, London,
Dr. John Snow identified the source of the water-borne epidemic.
Tuberculosis Death Rates
Fig. 2-24: The tuberculosis death rate is good indicator of a country’s ability to invest in
health care. TB is still one of the world’s largest infectious disease killers.
Avian Flu, 2003 - 2006
Fig. 2-25: The first cases of avian flu in this outbreak were reported in Southeast Asia.
HIV/AIDS Prevalence Rates, 2005
Fig. 2-26: The highest HIV infection rates are in sub-Saharan Africa. India and China
have large numbers of cases, but lower infection rates at present.