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Population Intro
Why important to study?
• More people on earth than at any other time in
history (6.5 bill)
• World’s pop increased faster in second half of
20th C than ever before
• Almost all global pop growth is occurring in
LDCs…poorest countries growing fastest…in
some cases leads to famine and human
• People are living longer – past 50 yrs global
life expectancy has increased by 20 yrs
Demography: study of human pop
Most demographers agree world pop
growth is slowing
Project pop will plateau at @ 12 bill
some time in 21st C
Historically pop growth has been
steady but certain events have
checked it…..disease has been and
continues to be biggest threat
2.1 Population Concentrations
Ecumene: portion of earth’s surface
occupied by permanent human settlement
• ¾ world pop live on 5% of earth’s
2/3 of world pop lives in 4 regions
• 1.) EAST ASIA (E. China, Japan, Taiwan,
China has 20 large urban areas, but 2/3 pop is rural
China = world #1
¾ Japan and Korea = urban
4 Populous Regions - contd
• 2.) SOUTH ASIA (India, Pakistan,
Bangladesh, Sri Lanka)
India = world #2
¾ rural
• 3.) EUROPE – E and W…mostly urban
• 4.) SE Asia (islands of Java, Sumatra,
Borneo, Papua New Guinea, Philippines,
Vietnam, Thailand)
Indonesia = world #4
Mostly rural
Top 10 Populous Nations
6. Pakistan
7. Russia
8. Bangladesh
9. Nigeria
10. Japan
• China and India expected to flip flop
• U.S. will stay #3 b/c of immigration
• LDCs taking top spots from MDCs
Population Density
Arithmetic Density: total # of people
divided by total area of land
• Can be misleading b/c is an average
• US = 78/sq mile, but Manhattan is
67,000/sq mile and Loving, TX .1/sq
• Highest = Bangladesh, Japan,
• Remember high pop (China) not
necessarily high pop density
Pop Density cont’d
Physiological Density: ratio of people
to a given unit of cultivable/arable
land (suited for agriculture)
• i.e. can you feed your population?
• Can be high b/c of high pop density or
poor land
• Ex: US 404/sq mile of arable land
Egypt 9,073/sq mile of arable land
Rule of Thumb….
• Pop increases rapidly where many more
born than die
• Slowly where births barely exceed
• Decreases where deaths outnumber
• Increases when people move in and
decreases when people move out
Pop Change…measured 3 ways
1. Crude Birth Rate CBR: total # of
births for every 1,000 alive
2. Total Fertility Rate TFR: average #
of children a woman will have during
child bearing yrs. Affected by:
culture, religion, lifestyle, is child
econ asset or drain, access to birth
control, mother’s educ and career
Pop Change – cont’d.
3. Natural Increase Rate NIR:
Calculates % by which pop grows each yr.
Ex: CBR = 20, CDR = 5, NIR = 1.5%
Excludes migration – only natural increase
A negative NIR means pop decreasing
World NIR peaked in 1963 at 2.2%
World NIR has declined in last 20 yrs.
What determines a nation’s NIR?
Factors to consider
Econ development
Gender Empowerment – status and
power to women
Health Care
Culture (i.e. Catholics or Mormons)
Public Policy (ex: China one child)
Factors determining a nation’s NIR
– cont’d.
Conclusions….countries w/ low econ
development, low educ, low gender
empowerment, but w/ lower infant
mortality rates b/c of improved
health care, cultural traditions
favoring fertility, and no public policy
limiting pop growth..have HIGHEST
Where are these countries?
LDCs: sub Sahara Africa, parts of
Middle East, parts of L. America
In MDCs pop growth is not natural
but due to immigration
Irony – fastest growing places are
least equip to deal w/ the growth
Doubling Time
Doubling Time: # of yrs needed for a pop
to double
• Formula 70/NIR…ex: NIR is 2.6 % DT is 70/2.6
= 27 years
• Pop growth is compounded/exponential (if rate
stays steady at 3% you’ll add more raw
numbers each yr b/c base gets bigger)
• At 3% rate, DT is less than 25 yrs. Taking
place in SS Africa, parts of ME, and parts of
Central America
Infant Mortality Rate: annual # of deaths
of infants under 1 yr compared w/ total #
of births
• In some parts of SS Africa is 10%
Life Expectancy: # or yrs a newborn can
expect to live..75 in most MDCs, late 30s
in some parts of Africa
Population Growth Curves
S Curve – historical growth
J Curve – exponential growth (fixed
Demographic Momentum
The tendency for pop growth to
continue despite strict family
planning b/c of young pop in child
bearing yrs
• Asia and LA 33% of pop under 15
• Africa 40% of pop under 15
• Ex: In 2002 both UK and S. Korea had
fertility rate of 1.6. But projections for
2025, older UK will decline by 2 mill and
youthful SK will add 2 mill.
2.3 Demographic Transition Model
4 stage model shows similar process
of pop change in all societies over
Every country is at some stage
The model is irreversible…you do not
go back
Very high CBR and CDR cancel each
other out
Almost no long term natural increase
Most of human history spent in stage
No country is here today
Rapidly declining CDR but CBR remains
high and = very high NIR
• @ 1750 – late 1800s nations in Ind Rev (Eur
and N. America) moved into stage 2. Improved
agric and health care dropped CDR.
• First time in world history to have significant
• LDCs entered stage 2 @1950 when MDCs
diffuse improved medical tech (vaccines) to
• Most of Africa in stage 2 today
CBR rapidly declines and CDR continues to
decline slowly. NIR begins to moderate
CBR drops b/c of social customs – access
to birth control, infant mortality rate
drops, women in work force, kids become
econ drain
Eur and NA enter - first half of 20th C
Asia and parts of LA moved here in recent
Very low CBR and CDR produce
almost no long-term natural increase
and possibly a decrease
Zero pop growth: CBR and CDR =
• TFR of 2.1 produces zero growth
Most Euro countries in stage 4 today
Countries w/ negative NIR…Russia
and Japan (shrinking)
Possible Stage Five?
In future if higher CDR than CBR
you’ll have irreversible pop decline.
If a country stays in stage 5 without
migration it will eventually cease to
Generalities of the Model
No one in stage 1; only a few have
reached stage 4
Model has 2 big breaks w/ the past
• First break: sudden drop in death rate
(stage 2) from technology and has
taken place everywhere
• Second break: sudden drop in birth rate
(stage 3) comes from changing social
customs and has not taken place
2.4 Population Structure and
Population pyramids…show age and
gender groups. How do MDC’s and
LDC’s differ?
• 1.) Sex Ratio: # of males per 100
females. In general slightly more males
born, but women outlive men
Eur and NA 95 males: 100 females
World wide 102 males: 100 females
Pop Structure and Composition –
2.) Age Distribution
• Dependency Ratio: # of people too old or
young to work, compared to # of people in
productive yrs.
% of pop under 15 = % over 65 divided by % in
between 15-65 multiplied by 100
Tells you how many dependents for every 100
Stage 2 countries: ratio is 1:1 (1 worker for every
dependent) Dependents are young
Stage 4 countries ratio is 2:1 (2 workers for every
dependent) Dependents are young and old
Age Distribution – cont’d
• Graying of the pop in MDCs – more than
¼ of all govn’t expenditures in US,
Canada, Japan, and W. Eur goes to
Social Security, health care, and other
programs for the elderly
• Baby Boomer Cohort in US (born 19461964)…what does this mean for you?
• Generation X = 1965-1980
Population Structure and
Composition – cont’d
Race and Ethnicity: Hispanics now
largest minority in US (recently
passed African Americans)
• 11% of US pop is foreign born
50% of that from LA
50% of that from Mexico
What do you see? Why?
Overpopulation and Sustainability
Should we worry @ overpopulation?
• Thomas Malthus – 1798 wrote “Essay
on the Principle of Pop” and argued
people need food to survive and have
natural desire to reproduce
Food prod increases arithmetically and pop
increases geometrically/exponentially
Predicted pop growth would eventually
outpace people’s ability to produce food
leading to starvation and famine
Malthus and his theory
Neo Malthusians
Argue that 2 characteristics of recent pop
growth make Malthus’ argument even
more frightening
• Esp high growth in LDCs
• Pop growth outpacing econ dev in many LDCs
(i.e. income rises 20% but pop rises 30%, so
some LDCs worse off than they were 30 yrs
• Paul Erlich – most prominent neo-Malthusian.
Wrote “Population Bomb” in 1968 – warned of
mass starvation due to overpopulation
Critics of Malthus
Malthus did not account for ability of
people to increase food prod dramatically
w/ new technology (go to video 3)
Malthus did not foresee family planning
and birth control and drop of CBR/NIR
Malthus did not recognize that famine is
usually NOT related to a lack of food but
to unequal dist of food – Marxist approach
Population and Sustainability
Carrying Capacity: # of people a given
area can maintain…surpassed in densely
populated places
Overpopulation implies a breach of an
area’s carrying capacity. Also involves
Over consumption of resources
Inefficient allocation of goods
Unsustainable land use
MDC’s blame LDC’s – have too many babies
LDCs blame MDCs – consume disproportionate
share of world’s resources
Control of Population
Pro-Natalist Policies – government
policies to promote reproduction and
bigger families
• Ex. Tax breaks
Anti-Natalist – government and
social policies that discourage
reproduction to reduce pop growth
• Tax breaks for sterilization
• One-child policies – may lead to gender imbalance
Control of Population
Improve local and state economies
• Better school, more eco opportunities
Reduce CBR through the use of
• Family planning programs in LDCs
• Why is this sometimes difficult?
Epidemiological Transition Model
At times high CDR have lowered NIR
Stage 1: Pestilence and Famine: i.e.
infectious diseases…ex: Black Plague
1350s kills ½ Eur pop
Stage 2: Receding Pandemics:
improved sanitation, nutrition,
medicine of Ind Rev decreases
spread of infect diseases
Epidemiological Transition Model
Stage 3: Degenerative and Human
Created Diseases
• Fewer deaths from infectious diseases
• Increase in chronic disease associated w/
aging (heart disease and cancer)
Stage 4: Delayed Degenerative Diseases –
degenerative diseases linger but life exp is
extended trough medical advances
(bypass, radiation, chemo, etc.)
Epidemiological Transition Model
Possible Stage 5 – Reemergence of
Infectious and Parasitic Diseases
• Evolution of new strains of bacteria (TB,
polio, malaria)
• Poverty – people cannot afford drug
treatment (TB)
• Improved travel diffuses diseases faster