Population and Demographics

1
Population and Demographics

• Where is the worlds population distributed and
  where has it increased?
• Why is population increasing at different rates
  in different countries ?

2
Distribution of World Population

• Population concentrations
• The four largest population clusters
• East Asia, South Asia, Southeast Asia Western
  Europe
• Other population clusters
• Sparsely populated regions
• Dry lands Cold lands
• Wet lands High lands
• Population density
• Arithmetic density
• Physiological density
• Agricultural density

3
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.)
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World Population Distribution Climate Zones
Fig. 2-2 World population is unevenly
distributed across the earths surface. Climate
is one factor that affects population density.
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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 worlds land area.
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Ecumene, 5000 B.C.
8
Ecumene, A.D. 1
9
Ecumene, A.D.1500
10
Ecumene, A.D.1900
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Measures of Population Density

• Arithmetic density the total number of people
  divided by total land area.
• Physiological density the number of people
  supported by a unit of areas of arable land.
• Agricultural density the ratio of the number of
  farmers to the amount of arable land.

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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.
13
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.
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Distribution of World Population Growth

• Natural Increase this is now 1.2 per year,
  but regional differences mean that most of the
  worlds additional people live in countries that
  are least able to maintain them.
• Fertility this is 2.7 for the world today, but
  varies greatly by region with many sub-Saharan
  countries exceeding 6 compared to less than 2 in
  nearly every European country.
• Mortality is related to infant mortality (the
  annual number of deaths of infants under 1 year
  of age compared with total live births) and life
  expectancy (at birth measures the average number
  of years a newborn can expect to live)

15
World Population Growth1950 - 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.
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Frequent Measures of Population Change

• Crude birth rate (CBR) the total number of live
  births in a year for every 1,000 people alive in
  the society.
• Crude death rate (CDR) the total number of
  deaths in a year for every 1,000 people alive in
  the society.
• Natural increase rate (NIR) the percentage by
  which a population grows in a year.

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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.
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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.
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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.
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Changes in Fertility Rates
21
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.
22
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.
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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.
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Variations in Population Growth

• The Demographic Transition
• 1. Low growth 3. Moderate growth
• 2. High growth 4. Low growth
• Population pyramids
• Age distribution
• Sex ratio
• Countries in different stages of demographic
  transition
• Demographic transition and world population growth

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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.
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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.
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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.
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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).
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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.
30
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.
31
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.
32
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).
33
Use of Family Planning
Fig. 2-22 Both the extent of family planning use
and the methods used vary widely by country and
culture.
34
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.
35
Tuberculosis Death Rates
Fig. 2-24 The tuberculosis death rate is good
indicator of a countrys ability to invest in
health care. TB is still one of the worlds
largest infectious disease killers.
36
Avian Flu, 2003 - 2006
Fig. 2-25 The first cases of avian flu in this
outbreak were reported in Southeast Asia.
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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.
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Where is the Worlds Population Distributed?

• Global population is concentrated in a few
  places.
• Human beings tend to avoid those parts of Earths
  surface that they consider to be too wet, too
  dry, too cold or too mountainous.
• The capacity of Earth to support a much larger
  population depends heavily on peoples ability to
  use sparsely settled lands more effectively.

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Where has the Worlds Population Increased?

• Virtually all the worlds natural increase is
  concentrated in the relatively poor countries of
  Africa, Asia and Latin America.
• In contrast, European and North American counties
  now have low population growth rates, and some
  are experiencing population declines.
• The difference in natural increase between MDCs
  and LDCs is attributable to differences in crude
  birth rates rather than in crude death rates.

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Why is Population Increasing at Different Rates
in Different Countries?

• The demographic transition is a change in a
  countrys population.
• A country moves from a condition of high birth
  and death rates, with little population growth,
  to a condition of low birth and death rates, with
  low population growth.
• During this process the total population
  increases enormously, because the death rate
  declines some years before the birth rate does.

41
Key Terms and Concepts

• Natural increase
• Fertility (total fertility rate)
• Mortality (infant mortality rate)
• Life expectancy
• Doubling time the number of years need to
  double a population, assuming a constant rate of
  natural increase (54 years at 1.2/year).

42
Will the World Face an Overpopulation Problem?

• Malthus on overpopulation
• Population growth and food supply
• Malthus critics
• Declining birth rates
• Malthus theory and reality
• Reasons for declining birth rates
• World health threats
• Epidemiological transitions

43
Food Population, 1950-2000Malthus 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.
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Key Concepts

• Population density
• Arithmetic density
• Physiological density
• Agricultural density
• Natural increase
• Total fertility rate
• Mortality
• Infant mortality
• Life expectancy
• Doubling time
• Zero population growth

• Crude birth rate
• Crude death rate
• Natural increate rate
• Demographic transition
• Population pyramids
• Malthusian catastrophe
• The principle of population
• Epidemiologic transition
• Pandemics
• The Olduvai Theory