Transcript Zero pop growth

UNIT TWO:
POPULATION
Population Intro
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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
suffering
• People are living longer – past 50 yrs global
life expectancy has increased by 20 yrs
DEMOGRAPHY
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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
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Ecumene: portion of earth’s surface
occupied by permanent human settlement
• ¾ world pop live on 5% of earth’s
surface….Why?
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2/3 of world pop lives in 4 regions
• 1.) EAST ASIA (E. China, Japan, Taiwan,
Koreas
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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)
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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)
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Indonesia = world #4
Mostly rural
Top 10 Populous Nations
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1.
2.
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China
India
U.S.A.
Indonesia
Brazil
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
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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
mile
• Highest = Bangladesh, Japan,
Netherlands
• Remember high pop (China) not
necessarily high pop density
Pop Density cont’d
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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
2.2 POPULATION GROWTH
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Rule of Thumb….
• Pop increases rapidly where many more
born than die
• Slowly where births barely exceed
deaths
• Decreases where deaths outnumber
births
• Increases when people move in and
decreases when people move out
Pop Change…measured 3 ways
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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.
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3. Natural Increase Rate NIR:
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NIR = CBR – CDR
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
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Econ development
Education
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.
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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
rates
Where are these countries?
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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
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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
MORTALITY
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CDR
Infant Mortality Rate: annual # of deaths
of infants under 1 yr compared w/ total #
of births
• In some parts of SS Africa is 10%
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Life Expectancy: # or yrs a newborn can
expect to live..75 in most MDCs, late 30s
in some parts of Africa
Population Growth Curves
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S Curve – historical growth
J Curve – exponential growth (fixed
percentage)
Demographic Momentum
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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
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4 stage model shows similar process
of pop change in all societies over
time
Every country is at some stage
The model is irreversible…you do not
go back
STAGE ONE: LOW GROWTH
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Very high CBR and CDR cancel each
other out
Almost no long term natural increase
Most of human history spent in stage
one
No country is here today
STAGE TWO: HIGH GROWTH
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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
growth
• LDCs entered stage 2 @1950 when MDCs
diffuse improved medical tech (vaccines) to
LDCs.
• Most of Africa in stage 2 today
STAGE THREE: MODERATE
GROWTH
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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
yrs
STAGE FOUR: LOW GROWTH
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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
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Most Euro countries in stage 4 today
Countries w/ negative NIR…Russia
and Japan (shrinking)
Possible Stage Five?
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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
exist
Generalities of the Model
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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
everywhere
2.4 Population Structure and
Composition
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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
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Eur and NA 95 males: 100 females
World wide 102 males: 100 females
Pop Structure and Composition –
cont’d.
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2.) Age Distribution
• Dependency Ratio: # of people too old or
young to work, compared to # of people in
productive yrs.
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% of pop under 15 = % over 65 divided by % in
between 15-65 multiplied by 100
Tells you how many dependents for every 100
workers
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
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Race and Ethnicity: Hispanics now
largest minority in US (recently
passed African Americans)
• 11% of US pop is foreign born
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50% of that from LA
50% of that from Mexico
What do you see? Why?
Overpopulation and Sustainability
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Should we worry @ overpopulation?
• Thomas Malthus – 1798 wrote “Essay
on the Principle of Pop” and argued
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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
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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
ago)
• Paul Erlich – most prominent neo-Malthusian.
Wrote “Population Bomb” in 1968 – warned of
mass starvation due to overpopulation
http://overpopulationisamyth.com/ov
erpopulation-the-making-of-a-myth
Critics of Malthus
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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
(Moderate approach)
http://overpopulationisamyth.com/ov
erpopulation-the-making-of-a-myth
Population and Sustainability
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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
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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
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Pro-Natalist Policies – government
policies to promote reproduction and
bigger families
• Ex. Tax breaks
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Anti-Natalist – government and
social policies that discourage
reproduction to reduce pop growth
rates
• Tax breaks for sterilization
• One-child policies – may lead to gender imbalance
Control of Population
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Improve local and state economies
• Better school, more eco opportunities
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Reduce CBR through the use of
contraception
• Family planning programs in LDCs
• Why is this sometimes difficult?
Epidemiological Transition Model
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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
Cont’d
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Stage 3: Degenerative and Human
Created Diseases
• Fewer deaths from infectious diseases
• Increase in chronic disease associated w/
aging (heart disease and cancer)
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Stage 4: Delayed Degenerative Diseases –
degenerative diseases linger but life exp is
extended trough medical advances
(bypass, radiation, chemo, etc.)
Epidemiological Transition Model
Cont’d
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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
(AIDS)