I. Population change
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Transcript of I. Population change
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GEOGRAPHY - CORE THEME #1POPULATIONS IN TRANSITION
2 BILLION
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Population growth since the Stone Age Population growth since 1750
Watch an animated dot map showing the evolution of the human population for the last 2000 years: http://www.youtube.com/watch?v=4BbkQiQyaYc
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The Malthusian ProjectionThomas Malthus, An Essay on the Principle of Population (England, 1798)
[There is a] constant effort towards an increase in population [which tends to] subject the lower classes of society to distress and to prevent any great permanent amelioration of their condition. The way in which these effects are produced seems to be this: we will suppose the means of subsistence in any country just equal to the easy support of its inhabitants. The constant effort towards population (…) increases the number of people before the means of subsistence are increased. The food therefore, which before supplied seven millions, must now be divided among seven millions and half or eight millions. The poor consequently must live much worse, and many of them be reduced to severe distress (…). The power of population is so superior to the power of the earth to produce subsistence for man, that premature death must in some shape or other visit the human race. The vices of mankind are active and able ministers of depopulation. They are the precursors in the great army of destruction, and often finish the dreadful work themselves. But should they fail in this war of extermination, sickly seasons, epidemics, pestilence, and plague advance in terrific array, and sweep off their thousands and tens of thousands. Should success be still incomplete, gigantic inevitable famine stalks in the rear, and with one mighty blow levels the population with the food of the world.
Paul Ehrlich, The Population Bomb, 1968
Population control – or race to oblivion? Overpopulation is now the dominant problem in all our personal, national and international planning. No one can do rational planning, nor can public policy be resolved in any area unless one first takes into account the population bomb (…). The battle to feed all of humanity is over. In the 1970s and 1980s hundreds to millions of people will starve to death in spite of any crash programs embarked upon now (…). Population control is the conscious regulation of the numbers of human beings to meet the needs not just of individual families, but of society as a whole.
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MAIN DEMOGRAPHIC INDICATORSType of indicator Indicator Definition Limitations
BIRTH
Crude Birth Rate (CBR)Number of live births per 1,000 people per year
Affected by age-sex structure
Total Fertility Rate (TFR)
Fertility of an imaginary woman who passes through her reproductive life(15-49) subject to all the age-specific fertility rates for ages 15–49 that were recorded for a given population in a given yearTo see how it is calculated, go to:www.ined.fr/en/everything_about_population/animations/fecondity/
Not based on the fertility of any real group of women
Replacement Fertility Rate
TFR needed to achieve demographic equilibrium (stable population): 2.1 to 2.3 (up to 3.0 for high CMR)
Doesn’t take into account migratory gains/losses
MORTALITY
Crude Death Rate (CDR)Number of deaths per 1,000 people per year Affected by age structure
Infant mortality Rate (IMR)
Number of infants who died before the age of 1 per 1,000 live births
Can be affected when counting mortality linked to infanticides or sometimes miscarriages
Child mortality Rate (CMR)Number of children who died before the age of 5 per 1,000 live births
Life expectancy
Average number of years of life remaining at a given age.To see how it is calculated, go to:www.ined.fr/en/everything_about_population/animations/life_expectancy/
Life Expectancy at Birth (LEB) depends highly on IMR or CMR, so demographers sometimes prefer Life Expectancy at Five (LEF)
NATURAL GROWTH Rate of Natural Increase Natural gain per 1,000 people per year (RNI = CBR – CDR)
Doesn’t take into account migratory gains/losses
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CBR Mexico
CDR Mexico
CBR Sweden
CDR Sweden
Birth and Mortality and Sweden and Mexico(1735-2000)
CBR: Crude Birth Rate (= live birth / 1000 people / year)CDR: Crude Death Rate (= death / 1000 people / year)
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Birth and MortalityIn the Middle East
(1950-2004)
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North America
EastAsia
North AfricaMiddle East Oceania
Europe
Sub-SaharanAfrica
Latin AmericaCaribbean
Central-SouthAsia
Russia
China
India
Brazil
Mexico
SouthAfrica
© 2011 Antoine Delaitre
Developed Countries
Post-Communist Transition
North/South Limit
Main Oil Exporters (OPEC)
Emerging Powers
Intermediary Countries
Least Developed Countries (LDCs)
DEMOGRAPHIC SITUATIONS: PATTERNS AT A GLOBAL SCALE
20% Pop.80% Wealth
80% Pop.20% Wealth
MEDCs (“North”) LEDCs (“South”)
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DEMOGRAPHIC TRANSITIONS (1950-2050)
SUB-SAHARAN AFRICA
2010
20102010
2010
WORLD
EAST ASIA EUROPE
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The Demographic Transition Model(DTM)
AFRICA
ASIA
EUROPE
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DTM stage Pre-Transition Early Transition Middle Transition Post-Transition
CDR / CBRHigh and stable CDR/CBR
(40-50)(“accidents”: famine,
epidemics)
Decreasing CDR (20-30)
High CBR (40-50)
Very low CDR (<10)Decreasing CBR (20-
30)
Moderate increase of CDR 10
Low CBR 10
RNI Low RNI< 10
Very high and increasing RNI
>20High but declining RNI
10-20Low or negative RNI
-5 to 10
Growth Stable or slow growth Very rapid growth Rapid but declining growth
Slow growth or decline?
Examples No examples today Sub Saharan AfricaLatin America, Middle
East, South Asia (India)
World average
Europe, North America, East Asia
(China)
4 STAGES OF THE DEMOGRAPHIC TRANSITION MODEL
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IMPACTING FACTORS MORTALITY FERTILITY
SOCIOCULTURAL FACTORS
Education (linked to healthcare/revenue) Age structure: lower CDR in younger populations (see CDR
Sub-Saharan African 1950-2050) vs higher CDR in older populations (see CDR in Europe 1950-2050)
Gender equality and status of women (measured by GDI – Gender Development Index)
Female education (linked to revenue/healthcare/birth control/professional ambition)
Age of marriage: couples (particularly women) tend to start procreating only once they are married
Residence can contribute to higher CBR:o Rural areas: rigid social pressures on women,
less state control (China), fewer educational opportunities for women
o Slums: young/poor population from rural background
Religion: most religions are opposed to birth control or contraception, but limited impact on actual behavior (ex: Algeria v Yemen, Brazil vs Poland)
ECONOMIC FACTORS
Revenue (affects nutrition, education, healthcare). Ex: Blacks vs Whites in South Africa
Nutrition (2500 cal/day recommended) (linked to revenue) Industrialization and technology (linked to better farming
outputs) Residence: slums (pollution, poverty: Rio de Janeiro), poor
rural areas (low farm productivity: Nordeste Brazil) Hazardous occupations: soldiers, miners, farmers, etc
Revenue: people with no retirement plans or social security in some countries see large families as able a means to increase the family’s workforce (farmers), and a protection for their old age
Standard of living: raising a child is costly in countries with a high standard of living
Professional ambition of women can be incompatible with repeated pregnancies
ENVIRONMENTAL FACTORS Pollution (respiratory diseases), heat (infants and seniors) Pollution may affect fertility (uncertain)
HEALTH FACTORS
Healthcare, primarily for infants (see IMR) or older people (see LEB) (linked to revenue/education)
Infectious diseases (LEDC: malaria, diarrhea, cholera, AIDS, etc) and degenerative conditions (MEDC: cancer, stroke, heart disease, obesity)
Access to clean water
Use of birth control, contraception, abortion (linked to education/healthcare)
Longer breastfeeding -> lower TFR Child’s survival rate (linked to healthcare/revenue):
low survival rate may encourage women to have more children to compensate for their losses.
POLITICAL FACTORS Wars, political instability, man-made famines (Sudan) Non coercitive pro-natalist policies: Western Europe
(limited impact) Strict anti-natalist policies: China, India
First, watch this animation about fertility: www.ined.fr/en/everything_about_population/animations/birth/
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FERTILITY AND ECONOMIC DEVELOPMENTSource: www.gapminder.org
Sub-Saharan Africa
South Asia / Middle East
East Asia
Latin America
Europe / North America
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National/State level TFR IMR LEB
Washington 1.80 5.1 79.4
Mississippi 2.26 10.7 73.9
USA 2.09 5.9 79.2
Uttar Pradesh 3.80 67 58.4
Kerala 1.70 12 73.5
India 2.76 54.6 63.5
Regional level TFR CMR LEBEurope
(East/West) 1.50 9 75.1
North America 2.26 7 79.3
East Asia 1.72 28 74
Latin America 2.04 28 73.4
North Africa / Middle East 2.94 45 70
South Asia 2.60 50 66
Sub-Saharan Africa 5.08 148 51.5
World 2.56 71 67.6
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TOTAL FERTILITY RATE (TFR)
2010 averages: World = 2.49 / MEDC = 1.65 / LEDC = 2.62
< 2
2-3
3-5
5-6
> 6
TFR
Niger: 7.19 Taiwan: 1.14
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INFANT MORTALITY RATE (IMR)
2010 averages: World = 47 / MEDC = 6 / LEDC = 52
Angola: 193
Japan: 3.3
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LIFE EXPECTANCY AT BIRTH
Japan: 82.1
Angola: 38.2
To estimate how many more years an average person like YOU is expected to live (note: it’s only an average!),go to http://calculator.livingto100.com/calculator
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EXAMPLES OF POPULATION PYRAMIDS
2008
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Age-sex ratios Definition Impact
Sex ratio% of men for 100 women
(human biological sex ratio: 105% at birth)
The sex ratio can sometimes be very imbalanced, for sociocultural or economic reasons, with problematic consequences: High sex ratio at birth (cultural preference for boys, abortions:
120% in China): shortage of brides, lower TFR High sex ratio adults (immigration of young men): Saudi Arabia
129% for age 15-64 Low sex ratio of adults (emigration of young men, alcohol,
cancer): shortage of husbands: loneliness of widows, depression. Russia: 92% at age 15-64, 44% for 65+
Ageing ratio # or % of people under 20 compared to people over 65
An ageing ratio too low or too high reveals future strains on public finances (education, retirement, health care) Low ageing ratio (France, Japan): the population is too old ->
challenge for health care and retirement Moderate ageing ratio (USA, Thailand, China): the population is
balanced High ageing ratio (Kenya, Niger): the population is too young ->
challenge for education
Dependency ratio
% of dependents (children+retirees)compared to productive population
(15-64)
High dependency ratio = burden on the working class to educate the young and/or support the elderly.Ex: Kenya, Niger= very high number of children
Low dependency ratio = there is a sufficiently large work force to support young/elderly.Ex: China, Thailand = large work force
France, Japan or USA have a moderate dependency ratio = the growing number of elderly is offset by the declining number of children
Median age The age that divides the populationinto two groups of equal size
Measure the age of a population: SEE TABLE WITH IMPACT OF AGEWorld median age in 2010 = 29.1 (ie: 50% are younger than 29.1)
AGE-SEX IMBALANCES
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TYPICAL POPULATION PYRAMIDS
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Pyramids Developing countries (LEDC) Developed countries (MEDC)
Shape Triangular pyramid Cylinder or spinning top
BaseWide base:
Poverty + poor education -> high TFR(TFR = 2.73, Africa = 7)
Narrow base:Affluence + good education -> low TFR
(TFR = 1.64)
TopNarrow top:
Poor health care -> low life expectancy(LEB = 66)
Widen top:Good health care -> high life expectancy
(LEB = 77)
Significance
“Population explosion”
Low median age + ageing ratio -> Large work force in 10-20 years. This can be beneficial ONLY IF that population can be educated and later find professional opportunities (ex: China), but represents a major challenge in very poor countries (ex: Niger, Uganda: 50% < age 15).
Confronted to those challenges, these countries usually try to adopt anti-natalist policies. But the poorest countries are also the ones who have the least government control to enforce any efficient policy (lack of funds, corruption, civil unrest)
“Population contraction” High median age + ageing ratio -> challenge for shrinking young generations who have to support a growing number of retirees (Germany, Japan) + risk of population contraction UNLESS fertility increases to allow the replacement of generations (>2.1) OR unless the country opens to immigration (double benefit: influx of young pop + immigrants are usually poorer, less educated and therefore tend to have a higher fertility rate) (ex: USA)
Confronted to those challenges, these countries usually try to adopt pro-natalist policies or push back the retirement age (ex: legal retirement age 60 -> 62 in France 2010?), while opening to immigration often remains a sensitive political issue (Japan, Western Europe)
TYPICAL POPULATION PYRAMIDS
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Youthful population(median age < 25)
Ageing population(median age > 35)
Opportunities
Young, dynamic, creative population -> progressivism Large work force in the short term future
Opposite of challenges of youthful population: good infrastructures, resources, food supplies, low unemployment, abundant resources, less social tension and crime.
New market (“third age”, “seniors”) -> active healthy population with free time (need for recreation, artistic or health care jobs)
Challenges
Pressure on infrastructures: housing shortage, slums, roads, water, sewage, etc
Pressure on services: education (crowded classrooms, low schooling rate, high illiteracy rate), health care (high infant mortality and low life expectancy, rapid spread of epidemics), transportation, police, etc
Pressure on food supplies -> malnourishment leading to occasional famine when coupled with civil unrest or climate accident
Pressure on working population (high dependency ratio) -> public debt
Pressure on job market -> unemployment, emigration (males) sometimes leading to unbalanced sex ratio, higher crime rates
Pressure on resources -> smaller farming lots, desertification, lack of water
Pressure on future generations (high population momentum) -> the challenges above will go on for at least a generation
Pressure on idle young men -> “youth bulge” leading to civil unrest, war or terrorism? (controversial theory of Gunnar Heinsohn, 2003)
Lack of dynamism and creativity -> conservatism
Pressure on retirement plans (high ageing ratio) -> reduced benefits, higher taxes, extension of working age
Pressure on health care (high life expectancy) -> increasing medical costs
Pressure on to allow immigration -> sensitive political issue
IMPACT OF AGE ON A POPULATION
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Japan: 44.7 China: 34.2 Kenya: 18.4France: 40.1 India: 25.0 Uganda: 15.0USA: 36.6 Egypt: 23.9 World: 29.1
MEDIAN AGE
Uganda: 15
Japan: 44.7
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Dependency ratio:• DR < 50%: low•DR 50-80%: moderate•DR > 80: high
Ageing ratio:• AR < 3: low•AR 3-5: moderate•AR > 5: high
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Population Momentum Factor:PMF < 1: negative momentum = snowballing effect of ageing population will lead to a decline without immigrationPMF = 1: no momentum = no snowballing effect of youthful/ageing and population can reach equilibrium if nothing changes PMF > 1: positive momentum = snowballing effect of the youthful population which will contribute to continued growth even with low TFR
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POPULATION EXPLOSION, EQUILIBRIUM OR CONTRACTION?
See how fertility (TFR) and life expectancy (LEB) impact the future of a population using your own simulation: www.ined.fr/en/everything_about_population/play_population/population_simulator/
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Wheat yields in developing countries(1950-2004)
Food intake (1964-2030)Recommended: 2,500 calories/day