Imagine that the number of
students in our AP HuG
Class has doubled. List the
effects of this, both positive
and negative. Would you like
to have more, fewer or the
same number of students in
the class as now?
Questions:
1. What services are easier to provide
for an area of high population density?
2. What qualities are desirable about
areas of lower population density?
3. If population continues to grow
locally, what is the impact on
population density?
Population Geography
•
•
•
•
•
•
Distribution of World Population
Population Statistics
Population Pyramids
Demographic Transition Theory
Population Control
Overpopulation
(Malthus and Neo-Malthusians)
Population
• Demography: The study of the Characteristics of human
population
– Demographers look statistically at how people are distributed
spatially by age, gender, occupation, fertility, health, etc.
• The distribution of the worlds population is in one word
“uneven”
A little information about world Population
• 80% of pop. Lives within 500 Mi. of an ocean
• World inhabitants live on only 10% of the land
• 90% of pop. Lives North of the Equator
• 65% lives between 20°N and 60 ° N latitude
Socrative Warmup Questions
1) Cartography is the art and science of
a) demographics.
b) mapmaking.
c) spatial orientation.
d) cognitive imagery.
e) making visualizations.
2) Which one of the following statements is most characteristic
of a refugee?
a) They usually move with official documentation.
b) Their first steps are often made on foot, by boat, wagon, or
bicycle.
c) They take all of their physical possessions with them.
d) Their chief motivation is to get new jobs.
e) They move at a leisurely pace.
3) The three largest population clusters in the world are in
a)
b)
c)
d)
e)
East Asia, South Asia, Southeast Asia
East Asia, South Asia, South America
Africa, South Asia, East Asia
Australia, South Asia, East Asia
Australia, East Asia, Europe
4) The Mercator projection preserves
a)
b)
c)
d)
e)
direction.
area.
shape.
scale.
distance.
Population Concentrations
• 23 countries = 75% of world
population (172)
• 10 Countries have pops. Greater
than 100M
• China, India, United States,
Indonesia, Brazil
World and Country Population Totals
Distribution and Structure: 3/4 of people live on 5% of earth's
surface!
Total: 6.6 billion on planet as of 2007
World Clock!
Five most populous regions and countries
REGION POPULATION COUNTRY POPULATION
•
•
•
•
•
East Asia
South Asia
Europe
SE Asia
East N. Am.
1.5 billion
1.2 billion
750 million
500 million
120 million
China
India
U.S.
Indonesia
Brazil
1.254 billion
986 million
274 million
206 million
168 million
Factors that Shape
Distribution
•
•
•
•
Accessibility
Topography
Soil Fertility
Climate
•
•
•
•
Weather
Water
Political History
Economic
History
Ecumene
Ecumene, or
portion of the
earth’s surface that
has permanent
human settlement
has expanded to
cover most of the
earth’s land area.
Expansion of the Ecumene
5000 BC - AD 1900
Population Density
• Density: numerical measure
of the relationship between
the number of people and
some other unit of interest
(typically space)
Population Density
• 2 Main Types of Densities
–Crude/Arithmetic
–Physiological
Arithmetic Density – the total number of people per a unit of land area.
U.S. = 76/mi2; NYC=1,000,000/mi2; Australia = 7/mi2
Physiological Density – the total number of people per a unit of arable
(farmable) land.
Crude/Arithmetic Density
• Total number of people divided by the total land area (also
called Population Density)
Limitations
• Assumes Uniformity
• One dimensional
• Tells little about opportunities or obstacles contained in the
relationship of people to land
Assumes Uniformity
Example: New York State
• 407.731 People Per Sq. Mile
(6th)
• Remove NY City Population of
8 Million and area of NYC 368
sq mi….
• Density = 240.19 People Per
Sq. Mile
Population Density of Georgia
Physiological Density
• Ratio of population to a given unit
of cultivated land
• Number of people dependant on
each unit of cultivated land
• Excludes agriculturally nonproductive land
• Reflects the “burden of
dependency” or “carrying capacity”
Physiological Density
• United States = 404 people are
supported by 1 sq mile of arable
land
• Egypt = 9,073 people per sq.
Mile
Why is Physiological Density
More meaningful than
Crude/Arithmetic Density?
Answer
• Physiological gives us a better picture
of the population’s strain on the
country’s resources
EXAMPLE
United States
Crude Density = 78 per sq. mi.
Physiological = 404 per sq. mi.
Egypt
Crude Density = 185 per sq. mi.
Physiological = 9,073 per sq. mi.
Population Density – Egypt
•All but 5% of
Egyptian people live
in the Nile River valley
•It is the only area in
the country that
receives enough
moisture to allow
intensive cultivation
of crops
Growth
Growth
In order to understand population
growth and change we must first
create an understanding of 2
significant factors:
- Fertility and Mortality
Measuring Population
• Geographers/Demographers
most frequently measure
population change in a country
through 3 measures
Measuring Population
–Crude Birth Rate (CBR)
–Crude Death Rate (CDR)
–Natural Increase Rate (NIR)
• Natural means excluding
migration
• Crude means looking at society
as a whole
Crude Birth Rate
• Total number of live births in a
year for every 1,000 people alive
–CBR of 20 means that for every
1,000 people in a country 20
babies are born over a oneyear period
–CBR for United States 2005 =
14.1
CBR = number of live births ÷ population x 1000
Crude Death Rate
• Total number of deaths in a year
for every 1,000 people
• CDR for United States 2005 = 8.2
CDR = number of deaths ÷ population x 1000
Natural Increase Rate (NIR)
• Percentage by which a population grows in a year
• Computed CBR – CDR after first converting the
two measures from numbers per 1,000 to % (#
per 100)
• CBR = 20 , CDR = 5
• 20 – 5 = 15 per 1,000 or 1.5% (15÷1000 x100)
Natural Increase
• World NIR for the 1st Half of the
20th Century = 1.3
–Peaked at 2.2 in 1963
–Declined sharply during the past
decade
Natural Increase
• 80 million people are added to the
world’s population annually
• High of 87 million in 1989
• Small % changes in the NIR are
very dramatic because the %
affects such a large base (7.1
billion people)
Rates of Natural Increase
Natural Increase = CBR - CDR
Effects of Natural Rate on a Large Base
Population
Demographic Equations
Growth Rate (%) = (Birth Rate – Death Rate) +/– Migration
(Rate of Natural Increase)
Population Doubling Time (yrs.) = 72  Rate of Natural Increase
Fertility
• Total fertility rate (TFR) average
number of children a woman will have
throughout her childbearing years
(15-49)
• TFR attempts to predict the future
(assumptions of future fertility on
current)
• World TFR is around 3.
–Sub Saharan Africa >6
–Europe <2
Total Fertility Rate (TFR)
Amount of children a women will have
on average during her child bearing
years.
High infant mortality tends to result in
higher fertility rates as families seek
“insurance” for the loss of children.
Fertility Rate = __number of live births during time period__ X 1,000
total population of females age 15-44 at
mid-point of time period
Total Fertility Rate - the average number
of children a women will have in her
childbearing years. This rate varies from
just over 1 (Japan, Italy) to around 7
(Niger, Mali). The U.S. rate is about 2.
2.1 is generally regarded
as the replacement rate
(the rate at which a
population neither grows
nor shrinks) in the
developed world. In less
developed countries this
rate should be higher to
account for so many
children not reaching
childbearing age.
England & Wales
Total Fertility Rate
Influences on Birth Rates
•
•
•
•
•
•
Family planning programs
Contraceptive technology
Role of mass media
Education/opportunities for women
Child mortality rates
Affluence/wealth
Mortality
• Infant mortality rate (IMR) annual #
of deaths of infants under one year
of age, compared with total live
births (usually deaths per 1,000)
Infant Mortality Rate (IMR) = __number of infant deaths during time period__ X 1,000
number of live births during time period
Infant Mortality Rate – the number of deaths of children under the age of one per
thousand live births. The rate ranges from as low as 3 (Singapore, Iceland) to as much
as 150 (Sierra Leone, Afghanistan). The U.S. rate is just over 6. High infant mortality
tends to result in higher fertility rates as families seek “insurance” for the loss of children.
Mortality
• Exceeds 100 in some LDC’s (10%)
–W. Europe < 1%
• Generally a reflection of a
country’s healthcare system
World Death Rates
• Infectious diseases
– HIV/AIDS
– SARS
• Degenerative diseases
– Obesity
– Tobacco use
• Epidemiological transition
– Communicable diseases/pathogens in less
developed countries
– Degenerative diseases in more developed countries
(obesity, heart disease, diabetes, cancer)
Adults and Children Living with HIV/AIDS, mid2006
Epidemiologic Transition
• Stages 1 and 2
– Infectious and parasitic
disease.
– “natural checks” according to
Malthus
• Stages 3 and 4
– Degenerative and human
created disease.
– Increase in chronic disorders
associated with aging (heart
attack, etc)
• Possible Stage 5
– Reemergence of infectious
and parasitic disease.
Life Expectancy
• Average number of years a
newborn infant can expect to live
at current mortality levels
• W. Europe = late 70’s
• Sub Saharan Africa = 40’s
Life Expectancy
Doubling Time
• How long will it take for a population of a
given area to double in size?
• Doubling time assumes the population will
grow at a given annual rate
• Approximated by dividing the annual rate
of population into 72
World = 50
MDC = 550
LDC = 40
Honduras = 22
Denmark = 700
Russia = never?
Example: Bangladesh
72/NIR => 72/2.09 = 34.4
years
Bangladesh with a population of
144.3 million people in 2005 will
have approximately 288.6
million people in 2039, if the
population continues to grow at
current rates.
9/16 Warmup Questions
1. Which of the following demographic statistics best measures
the level of reproduction occurring in a population?
a)
b)
c)
d)
e)
Composite birth statistics
Natal rate
CDR
CBR
TFR
2) Which of the following regions is currently experiencing the
fastest population growth?
a)
b)
c)
d)
e)
East Asia
Tropical Africa
Eastern Europe
The Sunbelt
Northeast United States
3) The demographic accounting equation does NOT take into
account ______________ when calculating a country’s
population.
a)
b)
c)
d)
e)
the death rates
emigration
natural increase over time
instances when natural increase is negative
immigration
The
Demographic
Transition Model
The Demographic Transition Model
• Model that shows changes in natural
increase, fertility, and mortality rates
• A process with several stages
Demographic Transition Model
www.prb.org/pdf04/transitionsinWorldPop.pdf
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.
The Demographic Transition
Model
• Every country in the world is in
one of the stages
• The process has a beginning,
middle, and end
• Once a country moves to a
stage it does not revert back
Demographic Transition Model
The Demographic Transition
• The Demographic Transition
– 1. Low growth
– 2. High growth
– 3. Moderate growth
– 4. Low growth
– 5. Negative growth?
• Population pyramids
– Age distribution
– Sex ratio
• Countries in different stages of demographic
transition
• Demographic transition and world population
growth
Demographic Transition Model
• Stage one
– Crude birth/death rate high
– Fragile population
• Stage two
– Lower death rates
– Infant mortality rate
– Natural increase high
• Stage three
– Indicative of richer developed countries
– Higher standards of living/education
• Stage Four
– CBR and CDR are at equilibrium or almost =
– ZPG= Zero Pop. Growth
– Most Northern and Western Euro countries
Stage/Phase 1: Low Growth (Pre-Industrial)
• Most of human occupancy of Earth occurred in
Stage 1
• CBR and CDR would rise and fall but typically
stayed at very high levels
Stage/Phase 1: Low Growth (Pre-Industrial)
• Therefore the natural increase was virtually zero
• Population remained unchanged (around
500,000)
Stage/Phase 1: Low Growth (Pre-Industrial)
• Between 800 B.C. and 1750 AD population
jumped from 5Million to 800 Million thanks to
agricultural revolution
Stage/Phase 1: Low Growth (Pre-Industrial)
• Humans remained at Stage 1 because of the
unpredictability of the food supply
• No Country is currently in Stage 1
Human Numbers Through Time: A.D. 0
• 2,000 years ago...
...at the dawn of the first millennium A.D. the
world's population was around 300 million
people.
Human Numbers Through Time: A.D. 1000
• 1,000 years later...
...the population had risen by as little as 10 million. And
well into the second millennium, it grew less than 0.1
percent each year. The numbers in Europe even fell in
the 1300s—struck down by the Black Plague. But
beginning in the late 18th century, the Industrial
Revolution would raise living standards and spur growth.
Stage/Phase 2: High Growth (Beginning of
Industrial)
• Around 1750 the natural increase jumped
from .05% to .5%
• Caused by several countries moving into Stage
2
Stage/Phase 2: High Growth (Beginning of
Industrial)
• In Stage 2 the CDR suddenly plummets while
the CBR remains at roughly the same level
(high)
• Causes a High Natural Increase = rapid
population growth
Stage/Phase 2: High Growth (Beginning of
Industrialism)
• Cause of drop in CDR was the Industrial
Revolution (made life better/easier)
• 1800 in Europe and N. America
Stage/Phase 2: High Growth (Beginning of
Industrialism)
• 1950 in Africa, Asia, and Latin America
• Other countries moved into Stage 2 quicker because of the
late 20th Century Medical Revolutions that were implanted
into the LDC’s
• LDC’s were given “Death Control”
• Edward Jenner 1796: Smallpox vaccine
Human Numbers Through Time: 1800
• 800 years later...
...the population had climbed to the landmark level of
one billion people. Almost 65 percent of all people lived
in Asia, 21 percent in a prospering Europe, and less than
1 percent in North America.
Stage/Phase 3: Moderate Growth
(Industrialization Complete)
• Movement from Stage 2 to Stage 3 occurs when the CBR begins
to drop sharply
• CDR is still dropping but not as sharply as CBR
• Pop. Still grows – just at a modest rate
• Europe and North America Enter 1st Half 20th Century
• Asia, Latin America in recent years, Africa – Not yet
What causes the Crude Birth Rate to
Drop?
Change in Social Customs
• People choose to have fewer children
• Parents understand the decline in mortality rates
• More service jobs, less farming jobs
• In urban areas children are not economic assets
• Urban homes are smaller
Stage/Phase 4: Low Growth (PostIndustrial)
• CBR = CDR = Natural Increase of 0 (called zero
population growth ZPG)
• Can still occur when CBR is higher than CDR because
some women die before reaching childbearing years
• Total Fertility Rate (TFR) 2.1 = ZPG
Demographic Transition
Model
Stage 1
Stage 2
Stage 3
Stage 4
Birth rate
Natural
increase
Death rate
Time
Source: Population Reference Bureau; and United Nations, World Population Projections to 2100 (1998).
Why such a low Fertility Rate in
Stage/Phase 4?
•
•
•
•
Women in Stage 4 work
Childcare is needed in order to work
Birth control
Upscale Activities
Stage/Phase 4/5 in other
Countries
Eastern Europe (especially Russia)
• Negative Natural Increase
• High Death Rates: poor pollution controls
during communist control, alcoholism
• Low Birth Rates
– “Family Planning” remains from communism
– In Russia women average 3.5 abortions
– Pessimism about the future
To Review…
Stage One
• Pre-industrial
• CBR and CDR high and
fluctuate according to
natural events and
disasters.
• Population is a constant
and young pop.
Stage Two
• Death rates drop…
improvements in
food supply,
sanitation, etc.
• Birth rates do not
drop… causes an
imbalance so there
is a large increase
in population.
Stage Three
• Birth rates fall
– Access to contraception
– Increase in wages
– Urbanization
– Move away from
subsistence agriculture.
– Education of women
• Population growth begins
to level off
Stage Four
• Low birth AND low
death.
• Birth rates may drop
below replacement
levels (Japan and Italy)
which may lead to
negative population
growth (Stage 5?).
• Large group born during
stage 2 ages… creates
a burden on the smaller
working population.
Soooo….
• A cycle, in a way, from 1 to 4
• Difference= in Stage 1 CBR and CDR are
high… in Stage 4 they are low.
• Difference= total population of a country
is higher in Stage 4 than in Stage 1
Problems with the Demographic
Transition Model
• based on European experience, assumes all countries will
progress to complete industrialization
• many countries reducing growth rate dramatically without
increase in wealth
• on the other hand, some countries “stuck” in stage 2 or stage 3
• it is not an exact science!!!!!!!!
Remember… Demographic
Transition is not only
dependent on CBR and CDR
but also on in and out
migration!!!!
If we are in Stage 4 then why is world
population increasing at such a rapid
rate?
Demographic Transition and
World Population Growth
• Second Half of the 20th Century
population increased rapidly because few
countries were in Stage 1 or 4
• Today no country is in Stage 1 and only a
few (the core) are in Stage 4
• Most countries are Stage 2 or 3; many
countries won’t reach Stage 4 any time
soon
Demographic Transition and World
Population Growth
Stage 4 is caused by 2 “breaks”
1. Drop in the Crude Death Rate
2. Drop in the Crude Birth Rate
•
•
N. America and Europe created their first break by creating the
Industrial Revolution
Therefore society had gradually moved to that point both socially
and economically
Demographic Transition and World
Population Growth
• However, the first break was artificially implanted into many other
countries
• The Regions of Africa, Parts of East Asia, and others were given the
ability to lower their Crude Death Rate
• This caused a massive change in population without the change in
societal structure that came in Europe and North America that would
eventually cause the Drop in the Crude Birth Rate
Causes for drop in Crude Birth
Rate
Change in Social Customs
•
•
•
•
•
•
•
People choose to have fewer children
Parents understand the decline in mortality rates
More service jobs, less farming jobs
In urban areas children are not economic assets
Urban homes are smaller
Women work
Birth Control
Does it Seem like these Changes in Social
Customs are occurring in the countries
that are currently in Stage 2?
Answer
• Only Europe, Australia and Parts of Asia
and North America are in Stage 4
• Other areas with already large population
centers are in Stage 2 or Stage 3
• The problem lies in how to encourage
those areas to reach Stage 4 (P.S. – Why
is staying in Stage 2 or Stage 3 a
“problem?”)
Birth and Death Rates for Sweden, 1740 - 2000
50
45
35
BR
30
25
DR
20
15
10
5
Birth and Death Rates for Mexico, 1900 - 2000
0
50
Birth Rate
Death Rate
45
40
Birth & Death Rates
Birth & Death rates
40
35
30
25
20
15
10
5
0
1900
1910
1920
1930
1940
1950
Birth Rate
1960
Death Rate
1970
1980
1990
2000
• How do the crude birth rate &
the fertility rate differ?
• Why do some analysts criticize
the applicability of the DTM to
all parts of the world?
• What types of geographic questions can be
answered by studying a population’s age and
gender composition?
Population in Demographic Transition
• A country’s stage in Demographic Transition gives it a
distinctive population structure
• The Demographic Transition Influences population
structure in 2 main ways:
• % of population in Each Age Group
• Distribution of males and females
We can visually see these influences by using
Population Pyramids
Population Pyramid
(Age/Sex Pyramid)
• Bar graphs displayed both horizontally and vertically showing
variations within particular subgroups or a population with
respect to certain descriptive aspects, such as birth or deaths
• Population pyramids are typically a representation of the
population based on its composition according to sex and age
Characteristics of Population Pyramids
• Males = left side of the vertical axis
• Females = right side of the vertical axis
• Age = order sequentially with youngest at the bottom and
oldest at the top
• Pyramid allows demographers to identify changes in the age
sex composition of a population
Population Pyramid
Developed Countries
• A country in stage 4 of the
Demographic Transition
Model
• Large number of “older
people”
• Smaller % of young people
Population Pyramid
Developing Countries
• A country in stage 2 of the
Demographic Transition
Model
• Large number of young
people and a smaller older
population
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 outmigration.
Moderate Growth in Chile
Chile entered stage 2 of the demographic transition in the 1930s,
and it entered stage 3 in the 1960s.
Age Distribution
• Dependency Ratio: number
of people who are too young
or too old to work, compared
to the number of people in
their productive years
Sex Ratio
• Sex Ratio: number of males
per hundred females
• In general more males are
born than females
• Males have higher death rates
3 age groupings
• 0-14 = Dependents
• 15-64 = Workers
• 64+ = Dependents
• Stage 2 Countries = 1:1
• Stage 4 Countries = 1:2
Sex Ratio
• Europe and North America =
95:100
• Rest of World = 102:100
Developing Countries
• Have large % of young people –
where males generally
outnumber females
• Lower % of older people –
where females are typically
more numerous
• High immigration = more males
Population Shift
An Aging World
Discussion
What are the implications of an
aging population for:
1. The U.S. housing market?
2. Social security and pension
funds?
3. Public financing of colleges
and universities?
4. Global migration flows?
Overpopulation
• When consumption of natural
resources by people outstrip the
ability of a natural region to replace
those natural resources.
Thomas Malthus
• An Essay on the Principle of
Population (1798)
• Earth’s population was
growing much more rapidly
than the Earth’s food
supply
Thomas Malthus
on Population
Malthus predicted:
• population would
outrun food supply
• decrease in food per
person.
Assumptions
• Populations grow
exponentially.
• Food supply grows
arithmetically.
• Food shortages and
chaos inevitable.
Reason…
• Population increases exponentially
• Food Supply increases arithmetically
Population J-Curve
Reasoning…
• Made prediction following England’s entrance
into stage 2 of DT
• Moral restraint needed to lower CBR or
something needs to increase the CDR
Neo-Malthusians
• Problem of overpopulation
will be even worse than
Malthus predicted
2 Main Reasons
• Malthus failed to anticipate how
many LDC’s would reach stage
2
• Overpopulation outstrips more
than just food production
Population and Resource Consumption
Technology, Energy Consumption, and Environmental Impact
There has been a dramatic increase in:
• individual energy use over time: 3,000 kcal/person - 300,000 kcal/person
• the power of technology to change the environment: think stone axe versus bulldozer versus atomic bomb.
• The scope and severity of environmental impacts.
Population and the
Environment
I=PxAxT
Impact = Population x Affluence x Technology
Population-influenced environmental problems:
• Global Warming
• Habitat Loss / Endangered Species
• Resource Depletion
• Food Shortages? Not globally, but regionally.
Criticism of Malthus
• Assumed world resources are
fixed rather than expanding
• Increased pop. could create
more resources
• Marxist argument that there
are plenty of resources only
an unequal distribution
Jean Antoine
Condorcet
(1743 – 1794)
• predicted that innovation,
resulting in increased wealth, and
choice would provide food and
resources in the future and lead to
fewer children per family
• believed that society was
perfectible
Ester Boserup
• 20th century Danish economist
• Argued that, "The power of
ingenuity would always
outmatch that of demand“
• People would deal with higher
population by using more
intensive agricultural methods
Boserup’s view of food production
Malthus and Reality
• Last half-century has not supported Malthus’s
theory
• Food production & effects of globalization
Malthus and Reality
• Cultural and societal changes
moved societies into stages 3
and 4 quicker
• Consistent drop in the NIR
• Caused by a drop in the CBR
–Economic Development
–Contraceptives