Transcript Chapter One

Population
APHG – Spring 2013
http://www.poodwaddle.com/clocks/worldclock
If we shrank the Earth's population to a village of
100 people, with all of the existing human ratios
remaining the same, there would be:
57 Asians
52 females
21 Europeans
48 males
8 Africans
14 people from the Western Hemisphere
(north and south)
30 Christians
6 U.S. citizens holding
70 Non-Christians
60% of the worlds wealth
70 unable to read
80 living in substandard housing
50 suffering from malnutrition
1 near death
1 near birth
Source: Mercy Housing Midwest, Omaha, NE.
1 with a college education
1 with their own computer
Critical Issues in Population
Geography
• More people are alive today than at any
other time in human history.
• The world’s population increased at a
faster rate during the second half of the
20th century than ever before.
• Virtually all population growth today
occurs in less developed countries
(LDCs)
Key Population Issues
Key Issues
1. Where is the world's population distributed?
2. Where has the world's population
increased?
3. Why is population increasing at different
rates in different countries?
4. Why might the world face an overpopulation
problem?
Population Distribution
Key Issue 1: Where Is the World's Population
Distributed?
 Population concentrations
 Sparsely populated regions
 Population density
The scientific study of population characteristics is demography. At a
global scale,. .. the world's so-called overpopulation problem is not
simply a matter of the total number of people . . . but the relationship
between number of people and available resources. At a local scale,
geographers find that overpopulation is a threat in some regions of the
world but not in others. Regions with the most people are not necessarily
the same as the regions with an unfavorable balance between population
and resources.
Distribution of World Population
Population concentrations
The four largest population clusters (2/3 of
world’s population)
1. East Asia – China, Japan, Korean Penn.
2. South Asia – India, Bangladesh, Pakistan,
Sri Lanka
3. Southeast Asia – Indonesia, Indochina Penn.
4. Europe – Western Europe, Eastern Europe
Other population clusters
1. Northeastern United States
2. Southeastern Canada
3. Western Africa – Half live in Nigeria
Population Distribution
World Population Distribution
World population is very unevenly distributed across the Earth’s surface
and it can be compared to climate distribution.
World Population Cartogram
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.)
Population Distribution
Sparsely populated regions
-The ecumene
-People generally avoid:
Dry lands
Cold lands
Wet lands
 High lands
Expansion of the Ecumene
5000 B.C.–A.D. 1900
The ecumene, or the portion of the Earth with permanent human settlement, has
expanded to cover most of the world’s land area.
World Population Distribution by Region
1800–2050
Population Density
 Arithmetic Density – the total number of people
divided by the total land area ( This measure is also
called population density.) Arithmetic density enables
geographers to make approximate comparisons of
the number of people trying to live on a given piece of
land in different regions of the world.
 There is no relationship between arithmetic density
and standard of living.
Arithmetic Population Density
Arithmetic population density is the number of people per total land area.
The highest densities are found in parts of Asia and Europe.
Effect of Migration on
Population Growth
Q&A. How densely populated is the planet?
 1st Western Europe, 433 people per sq. mile
 2nd Caribbean, 417 people per sq. mile
 Least densely settled region is Oceania: 10 people
per sq. mile
 United States is 78 people per sq. mile
Q. Does high density in urbanized areas equal
environmental degradation????
Population Densities, 2003
Region
World
More Developed Countries
Less Developed Countries
Africa
Sub-Saharan Africa
Northern Africa
Western Africa
Eastern Africa
Middle Africa
Southern Africa
North America
Latin America
Central America
Pop./Sq. Mile
122
61
160
74
76
57
108
107
41
49
42
68
150
Source: Population Reference Bureau, 2003 World Population Data
Caribbean
417
South America
52
Asia
312
Western Asia
112
South Central Asia 376
Southeast Asia
313
East Asia
334
Europe
82
Northern Europe 141
Western Europe 433
Eastern Europe 41
Southern Europe 288
Oceania
10
Physiological Density
 A more meaningful population measure is by looking
at the number of people per area of a certain type of
land in a region.
 The number of people supported by a unit of arable
land is called the physiological density.
 Comparing physiological and arithmetic densities
helps geographers to understand the capacity if the
land to yield enough food for the needs of people.
Physiological Density
Physiological density is the number of people per arable land area. This is good
measure of the relation between population and agricultural resources in a society.
Agriculture Density
 Two countries can have similar physiological
densities, but they may produce different amounts of
food because of different economic conditions.
Agriculture density is the ratio of the number of
farmers to the amount of arable land.
 The Netherlands has a much higher physiological
density than does India but a lower agriculture
density.
 Agriculture density is directly related to standard of
living
Measures of Density
Distribution of World Population
Growth
Key Issue 2: Where has the World’s
Population Increased?
Natural Increase – the percentage by which
a population grows in a year
Crude birth rate (CBR) – the number of
births per 1,000 population
Crude death rate (CDR) – the number of
deaths per 1,000 population
Doubling time – the number of years needed
to double a population
World Population Growth
1950–2010
Total world population increased from 2.5 to 6 billion in this half century. 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.
World Population Growth, 1750–2150
Source: United Nations, World Population Prospects, The 1998 Revision; and estimates by the Population Reference Bureau.
http://www.youtube.com/watch?v=9_9SutNmfFk&feature=BF&list=ULadYPZ59_AUc&index=1
Natural Increase
Q&A: When could world population stop
growing?
First one – half million years: the population
growth rate was about zero
1700s modern era of population growth
began
Between 1850 and 1900, the annual growth
rate reached 0.5 percent
By the mid-1960’s rate surged to 2.0 percent
Dropped to 1.7 percent by the mid-1980s,
and declined to about 1.4 percent by 2000.
Natural Increase Rates
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
The crude birth rate (CBR) is the total number of births in a country per 1,000
population per year. The lowest rates are in Europe, and the highest rates are in
Africa and several Asian countries.
Crude Death Rates
The crude death rate (CDR) is the total number of deaths in a country
per 1,000 population per year. Because wealthy countries are in a late
stage of the demographic transition, they often have a higher CDR than
poorer countries.
Population Growth through Natural Increase,
1775–2000
Total Fertility Rates
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
The infant mortality rate is the number of infant deaths per 1,000 live births
per year. The highest infant mortality rates are found in some of the poorest
countries of Africa and Asia.
World Infant Mortality Rates
in Selected Countries, 2000
Source: Carl Haub and Diana Cornelius, 2000
World Population Data Sheet (Washington, DC:
Population Reference Bureau, 2000).
Life Expectancy at birth
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.
Doubling Time
• Doubling Time of a population (years) :
– 70 / Population Growth Rate (%)
( 70 / 2.0% = 35 years )
– Rule of 70 :determine how long it would
take for a population to double at its
present growth rate.
– divide 70 by the population’s annual
growth rate to determine the years
needed to double the size of the
population.
Human Population Doubling Time
Why has the worlds population
grown at such different rates
throughout history?
3 variables: births, deaths, and migration
Balancing Equation:
A. The difference between births and deaths in a
population produces the natural increase(or decrease)
of a population.
B. Net migration is the difference between the number
of persons entering a geographic area (immigrants)
and those leaving (emigrants)
C. Natural increase usually accounts for the greatest
amount of growth in a population, especially within a
short period of time.
Population increases at
different rates
Key Issue 3: Why is population increasing
at different rates in different countries?
The demographic transition model
Population pyramids
Countries in different stages of
demographic transition
Demographic transition and world
population growth
Demographic Transition Model:
Development & Population Intersect…
Demographic Transition
Stage 1: Early Stationary Stage
 Population growth: slow increase
 Birth rates: high
 Death rates: high
Most of humanity’s several-hundred year occupancy of Earth
was characterized by stage 1. Birth and death rates varied
considerably from one year to the next and from one region to
another, but over the long term they were roughly comparable,
at very high levels.
Between 8000 B.C. and A.D. 1750, Earth’s human population
increased from 5 million to 800 million. The burst of population
growth around 8000 B.C. was caused by the agriculture
revolution. Despite the agriculture revolution, the human
population remained in stage1 of the demographic transition
because food supplies were unpredictable.
Demographic Transition
Stage II: Early Expanding Stage
 Birth rates: high
 Death rates: decreasing
 Population growth: rapid and increasing
After around A.D1750 the world’s population suddenly began to
grow10 times faster than in the past. In stage II, the crude death
rate plummets, while the crude birth rate remains the same as in
stage I. Most African countries are still in a stage II.
With the advent of the Industrial Revolution and the
improvements in technology, population growth rate changed.
Countries in Europe and North America entered stage II of the
demographic transition about 1800, but stage II did not diffuse to
most countries in Africa, Asia, and Latin America until the
1950’s. The late 20th century push of countries into stage II was
caused by the medical revolution.
Percent of Population under 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.
Rapid Growth in Cape Verde
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.
Demographic Transition
Stage III: Late Expanding Stage
 Birth rates: decreasing
 Death rates: leveling off
 Population growth: rapid but slowing
A country moves from a stage II to a stage III when the birth rate
begins to drop sharply. European and North American countries
moved from stage II to a stage III during the first half of the 20th
century. Most countries in Asia and Latin America have moved
to a stage III in recent years.
A society enters a stage III when people decide to have fewer
children. Medical practices introduced in stage II improve the
probability of infant survival, but many years pass before
families react by conceiving fewer babies.
Demographic Transition
Stage III continued……
Economic changes in stage III also induce families to have
fewer offspring. Farmers often consider a large family to be an
asset. In contrast, children living in cities are generally not
economic assets.
About 75% of the world’s population is stranded in stages II and
III.
Q&A: What does improve technology increase?
resource availability
standard of living
health care
?
?
Moderate Growth in Chile
Chile entered stage 2 of the demographic transition in the 1930s, and it
entered stage 3 in the 1960s.
Demographic Transition
Stage IV: Late Stationary Stage
 Birth rates: low
 Death rates: low
 Population growth: low
A country reaches stage IV when the birth rate declines to the
point where it equals the death rate. The condition is called
ZPG. Most European countries have reached stage IV. The
United States has moved slightly below ZPG since 2000. When
families lived on farms, employment and child rearing were
conducted at the same place, but in urban societies parents
leave the home to work.
Changes in lifestyles also encourage smaller families. Several
Eastern European countries, most notably Russia, have
negative natural increase rates, a legacy of Communist rule.