UNIT TWO: POPULATION. Population Intro Why important to study? Why important to study? More people...
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Transcript of UNIT TWO: POPULATION. Population Intro Why important to study? Why important to study? More people...
UNIT TWO: POPULATION
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
• People are living longer – past 50 yrs global life expectancy has increased by 20 yrs
Population Intro (cont.)
• 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
Demography: study of human population
Most demographers agree world pop growth is slowing
Project pop will plateau at @ 12 billion some time in 21st Century
How Get Demographic Information? --The Census
The US Census is taken every 10 years to count the population of the country.
Gender, Age, Race, Income, Disabilities, Education . .
The #’s are important as they determine government funding
Many protest that not all of the population is counted – homeless, undocumented
UN collects data on world population, as well as, The World Bank and Population Reference Bureau
DEMOGRAPHY
Historically, pop growth has been steady but certain events have checked it…..disease has been and continues to be biggest threat
The Plague Spanish Flu
2.1 Population Concentrations
Ecumene: portion of earth’s surface occupied by permanent human settlement• ¾ world pop live on 5% of
earth’s surface….Why?• Dry Lands• Wet Lands• High Lands• Cold Lands
2.1 Population Concentrations 2/3 of world pop lives in 4
regions• 1.) EAST ASIA (E. China,
Japan, Taiwan, Koreas 1/5 of the world’s
population Clustered near the coast China has 20 large urban
areas, but 2/3 pop is rural China = world #1 in
population 3/4 of Japan and Korea is
urban
4 Populous Regions – (cont.d)• 2.) SOUTH ASIA (India,
Pakistan, Bangladesh, Sri Lanka)1/5 of the world’s population
Clustered near riversConfined by natural boundaries (Himalayas . . .)
India = world #2 in population
¾ rural/farmers
4 Populous Regions – (cont.d)
• 3.) EUROPE – E and W…mostly urban
• mostly urban• 1/9 of the world’s population
4 Populous Regions – (cont.d)
• 4.) SE Asia (islands of Java, Sumatra, Borneo, Papua New Guinea, Philippines, Vietnam, Thailand) Indonesia = world #4Mostly ruralMainly islandsClustered near rivers and deltas
Mostly rural, but very congested cities
Top 10 Populous Nations
1. China 6. Pakistan 2. India 7. Russia 3. U.S.A. 8. Bangladesh 4. Indonesia 9. Nigeria 5. Brazil 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 • Highest = Bangladesh, Japan,
Netherlands• Remember high pop (China) not
necessarily high pop density
Problems with Arithmetic Density
Arithmetic Density does not always accurately portray population distribution.
• Can be misleading b/c is an average• Examples: Egypt had a population
of 73.3 million in 2004, and an arithmetic density of 190 per square mile. However, 98% of the population lives on only 3% of the land making the density meaningless.
• US = 78/sq mile, but Manhattan is 67,000/sq mile and Loving, TX .1/sq mile
Population 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
Agricultural Density Definition: ratio of farmers to
the amount of arable land. MDC’s have LOW Agricultural
Density because of technology.
Putting Agriculture and Physiological densities together allows you to look at the relationship between population and resources.
Density Chart
Arithmetic Density
Physiological Density
Agricultural Density
Canada 3 65 1
US 32 175 2
Egypt 79 2296 251
Japan 338 2695 46
India 356 690 163
Netherlands 398 1748 23
Bangladesh 1127 1927 472
2.2 POPULATION GROWTH
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
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 education and career
Population Change (cont.d)
3. Natural Increase Rate “NIR”: • 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
Economic development Education Gender Empowerment – status
and power of 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 education, 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?
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 equipped 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
MORTALITY 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%
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 percentage)
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 time
Every country is at some stage The model is irreversible…you do
not go back
STAGE ONE: LOW GROWTH
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
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
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
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 exist
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 everywhere
2.4 Population Structure and Composition
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 – cont’d.
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 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 1946-1964)…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 ago)
• Paul Erlich – most prominent neo-Malthusian. Wrote “Population Bomb” in 1968 – warned of mass starvation due to overpopulation
http://overpopulationisamyth.com/overpopulation-the-making-of-a-myth
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 (Moderate approach)
http://overpopulationisamyth.com/overpopulation-the-making-of-a-myth
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 rates• 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 contraception • 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 Cont’d
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 Cont’d
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)