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Human Populations: Population Dynamics
IB syllabus: Ch 12 Video: Population connection video Population Paradox – world in the balance
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Syllabus Statements 3.1.1: Describe the nature and explain the implications of exponential growth in human populations 3.1.2: Calculate and explain, from given data, the values of crude birth rate, crude death rate, fertility , doubling time and natural increase rate 3.1.3: Analyze age/sex pyramids and diagrams showing demographic transition models 3.1.4: Discuss the use of models in predicting the growth of human populations
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vocabulary Crude birth rate Crude death rate Demographic transition Doubling time Fertility Rate of natural increase
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Factors Effecting Population Size
3 factors effecting population birth, death, & migration Population change = (Birth + Immigration) – (Deaths + Emigration) Rates more often used Crude Birth rate = # live births / 1000 people in year population Crude Death rate = # deaths / 1000 people in year population
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World 21 9 All developed countries 11 10 All developing 24 8
Average crude birth rate Average crude death rate World All developed countries All developing Developing (w/o China) 21 9 11 10 24 8 29 © 2004 Brooks/Cole – Thomson Learning
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© 2004 Brooks/Cole – Thomson Learning
Africa Latin America Asia Oceania United States North Europe 38 14 23 6 20 7 18 15 9 10 11 © 2004 Brooks/Cole – Thomson Learning
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World Population Change
Worldwide birth and death rates dropping Death rate dropping faster than birth rate 216,000 people added to world population daily Exponential population growth still occurring but slower - Population counter But base number still increasing 79 x 106 people added per year
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World Population over the Centuries
9,000 human beings added to the planet every hour
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<1% 1-1.9% 2-2.9% 3+% Data not available Annual world
population growth <1% 1-1.9% 2-2.9% 3+% Data not available
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Reasons for the Human Population Explosion
Death rates dropping faster because of Causes of disease recognized Improvements in nutrition Discovery of antibiotics Improvements in medicine Increase in number of women who actually reach child-bearing age % Survival Age Birth Death A B Survival changed from B to A
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Implications of Exponential Growth
Biotic potential exceeds environmental resistance: birth rates exceed death rates Outstrip our resource base – nonrenewable gone, renewable maybe used faster than replaced Increase strain on the environment – pollution, sanitation needs, biodiversity loss Increase food production & land under production
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Average Number of Children, Grandchildren, and Great Grandchildren
14 5 258 America West Germany Africa
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Fertility Replacement fertility – number of children a couple must bear to replace themselves – roughly 2.1 Reaching replacement fertility now would still cause population growth for another 50 years Total fertility rate (TFR)= # of children a woman will have in her childbearing years (15-49) TFR = 1.6 in developed countries, 3.1 in developing countries
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Calculating Fertility Rates and Doubling Times
(CBR – CDR)/10 = Rate of increase or decrease in population per 1,000 per year 70/Rate of Increase = Doubling Time
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Calculating Fertility Rates and Doubling Times: Practice
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Calculating Fertility Rates and Doubling Times: Answers
350
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Worldwide TFR in 2002 Births per woman < 2 4-4.9 2-2.9 5+ 3-3.9
Data not available Worldwide TFR in 2002
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Population (billions)
Population projections based on TFR (H = 2.6, M = 2.1, L = 1.7) 12 11 High High 10.9 10 Medium Low 9 Medium 9.3 8 Population (billions) 7 6 Low 7.3 5 4 3 2 1950 1960 1970 1980 1990 2000 2010 2020 2030 2040 2050 Year
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Births per thousand population
US fertility and the “baby boom” 4.0 3.5 3.0 2.5 2.0 2.1 1.5 1.0 0.5 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 Year Births per woman Baby boom ( ) 32 30 28 26 24 22 20 18 16 14 Births per thousand population 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 Year Demographic transition Depression End of World War II Baby boom Baby bust Echo baby boom
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Factors effecting Birth & TFR
Importance of children for labor higher in developing countries & rural areas Urbanization more family planning resources, less need for children in cities Cost of raising or educating children more expensive to raise in developed areas Education & Employment for women less opportunity outside of house higher TFR 5. Infant mortality rate When infant mortality lower fewer children needed Average age at marriage Fewer children when 25 or older for marriage Availability of pension Eliminate need for kids to take care of you Availability of Legal abortion Availability of & Reliability of birth Control Religious beliefs, traditions, cultural norms
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Life & Death Infant mortality and Life Expectancy are good indicators of health in a country Global life expectancy is increasing Poorest countries it may still be low or even falling (AIDS in Africa) Infant mortality encompasses nutrition & health care so it’s a good measure Still 8 million infants worldwide dieing of preventable causes in first year of life US – teen pregnancy rate highest of all industrialized countries
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Infant deaths per 1,000 live births
<10 10-35 36-70 71-100 100+ Data not available
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Different Worlds Rich nations, poor nations
Population growth in rich and poor nations Different populations, different problems
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Population (2002) Population projected (2025) Infant mortality rate
United States (highly developed) 288 million 174 million Brazil (moderately developed) 130 million Nigeria (less developed) Population projected (2025) 346 million 219 million 205 million Infant mortality rate 6.8 33 75 Life expectancy 77 years 69 years 52 years Fertility rate (TFR) 2.1 2.2 5.8 %Population under age 15 21% 33% 44% % Population over age 65 13% 5% 3% Per capita GNI PPP (2000) $34,100 $7,300 $800 © 2004 Brooks/Cole – Thomson Learning
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Economic Categories Based on Per Capita Gross National Income
High-income, highly developed, industrialized countries United States, Japan, Canada Average GNI per capita = $26,710 Middle-income, moderately developed countries Latin America, South Africa, China Average GNI per capita = $1,850 Low-income, developing countries Western and central Africa, India, central Asia Average GNI per capita = $430
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Disparities Developed countries Low-income developing countries
16% of the world’s population Control 81% of the world’s wealth Low-income developing countries 41% of the world’s population Control 3.4% of the world’s gross national income Difference in per capita income: 62 to 1!
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Population Increase in Developed and Developing Countries
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© 2004 Brooks/Cole – Thomson Learning
Developed Countries 50 © 2004 Brooks/Cole – Thomson Learning 40 Rate of natural increase Rate per 1,000 people 30 Crude birth rate 20 Crude death rate 10 Rate of natural increase = crude birth rate – crude death rate 1775 1800 1850 1900 1950 2000 2050 Year
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© 2004 Brooks/Cole – Thomson Learning
Developing Countries 50 Crude birth rate © 2004 Brooks/Cole – Thomson Learning 40 Rate of natural increase Rate per 1,000 people 30 Crude death rate 20 10 1775 1800 1850 1900 1950 2000 2050 Year
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Population Age Structure
Analysis by sex, of the proportion of population at each age level 3 main age categories Prereproductive: 0 – 14 years Reproductive: 15 – 44 years Postreproductive: 45 and up Represent a good comparison between countries Compare Growth Rapid, Slow, Zero, Negative
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© 2004 Brooks/Cole – Thomson Learning
Male Female Male Female Rapid Growth Guatemala Nigeria Saudi Arabia Slow Growth United States Australia Canada Ages 0-14 Ages 15-44 Ages © 2004 Brooks/Cole – Thomson Learning
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© 2004 Brooks/Cole – Thomson Learning
Male Female Male Female Zero Growth Spain Austria Greece Negative Growth Germany Bulgaria Sweden Ages 0-14 Ages 15-44 Ages © 2004 Brooks/Cole – Thomson Learning
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Age Structure & Population Growth
Country with many people under 15 has large potential for population increase Depends on the number of females as well In % of world population was below 15 (33% in developing countries) Population has stabilized or declining in most developed countries Many developing countries expected to double or triple before stabilizing Mexico, Ethiopia, Nigeria, Pakistan, Brazil
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Population Momentum Countries like Iraq will continue to grow for 50–60 years even after the total fertility rate is reduced to replacement level.
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Projections of Population and Economics
Track the baby boomers through age pyramids Currently ½ of adult Americans Dominate demand for goods, services, & control politics and laws The social security problem – Paid for by current workers, fewer than boomers Future impact = later retirement, more taxes, …
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© 2004 Brooks/Cole – Thomson Learning
Age Females Males 2015 20 16 12 8 4 Millions Age Females Males 1955 16 12 8 4 20 Millions Age 24 20 16 12 8 4 Females Males 1985 Millions Age 24 20 16 12 8 4 Females Males 2035 Millions 20 © 2004 Brooks/Cole – Thomson Learning
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Number of workers supporting each Social Security beneficiary
40 1945 41.9 workers 30 20 Number of workers supporting each Social Security beneficiary 1950 16.5 10 2075 1.9 1945 2000 2050 2075 Year
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Problems with Population decline
If many populations stable now At some future time they will begin to decline By 2050 – 39 countries are expected to be in decline If rapid, can cause problems (1) consume public services, health care, social security; (2) labor shortage, increased reliance on immigrant labor
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40 35 30 25 20 15 10 5 1950 1970 1990 2010 2030 2050 2070 2090 2110 2130 2150 Year Age Distribution (%) Global Aging Under age 15 Age 60 or over Age 80 or over
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Population decline from rising death rates
HIV epidemic in Africa kills 6000 daily Kills mostly young adults Sharp decrease in average life expectancy Loss of productive workers Rise in numbers of orphans Drop in food production with loss of laborers Need new Marshall Plan Reduce HIV spread: education, health services Restore economic progress: aid as $ & volunteers
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Is the world overpopulated?
Wrong question? What is the optimum number of people that can be sustainably supported by the earth without further environmental degradation Optimum would allow people to live comfortably without harming future generations
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Solutions Reducing births!
Violation of personal and religious freedoms Viewed as a form of genocide by some ethnic groups BUT We currently don’t provide basic needs for 1/6 of the world population Increasing environmental harm & death rates Life span longer today so we have a greater per person impact too
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Demographic Transition Hypothesis
As countries become industrialized first death rate then birth rate will decline Preindustrial Stage harsh living conditions = little population growth, high B & D Transitional Stage industrialization starts, better healthcare & food = population growth is rapid, high B & lower D Industrial Stage Industry continues = population grows but slowly, B > D by a little Postindustrial Stage population growth stops, B = D (13% of world) then B < D an may start to decline (this may be stage 5)
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Relative population size Birth rate and death rate
Stage 1 Preindustrial Stage 2 Transitional Stage 3 Industrial Stage 4 Postindustrial Low High Relative population size (number per 1,000 per year) Birth rate and death rate 80 70 60 50 40 30 20 10 Birth rate Death rate Total population Low growth rate Increasing growth rate Very high growth rate Decreasing growth rate Low growth rate Zero growth rate Negative growth rate Time
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Demographic Transition Comparisons
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Demographic Transition Hypothesis
Most developing countries today have death rates declining more than birth rates Still in Transitional stage Fear that population growth in these areas will overcome economic growth Demographic Trap: get stuck in a stage Countries lack skilled workers, capital & resources, drop in economic assistance
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Can we reduce Birth rates
Doing so will reduce abortion rates & save lives as well Family Planning – info on birth spacing, birth control and prenatal care Empowering women – education, job opportunities, womens rights Women work 2/3 all hours worked, 10% income Economic Rewards & Penalties – payments to individuals who use contraceptives
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Global Contraceptive Use Condom 5% Male sterilization 5% Pill 8% Other
methods 10% No method 43% IUD 12% Female sterilization 17%
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India: A Case Study World’s first national family planning program
After 50 years it is still the second most populous country in world (1 billion) GNIPP is $2,340 a year Unemployment = 50% 40% population, 50% children suffer malnutrition 16% world population, 2% resources ½ cropland degraded, 70% water seriously polluted Overall, program disappointing & poorly done
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China: A Case Study cut crude birth rate in half, TFR from 5.7 to 1.8 children per woman Encourage late marriage & 1 child per family Contraception. Sterilization, Abortion = FREE Reward Food, $$$, School tuition, Medical care UN projects population drop by 2042 It was either population control or starvation Population still growing, mass environmental impact But projected to be on the decline by 2040
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India China Percentage of world 16% population 21% Population (2000)
1 billion 1.3 billion Population (2025) (estimated) 1.4 billion 1.4 billion Illiteracy (%of adults) 47% 17% Population under age 15(%) 36% 25% Population growth rate (%) 1.8% 0.9% Total fertility rate 3.3 children per woman (down from 5.3 in 1970) 1.8 children per woman (down from 5.7 in 1972) Infant mortality rate 72 31 Life expectancy 61 years 71 years GNP per capita (1998) $440 $750
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Cutting Global Population Growth
UN encouraging world population stability Universal access to family planning Improve health care – infants, children, women Social & Economic plans for countries Increase access to education Eradicate poverty Eliminate unsustainable patterns of production and consumption
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The use of Models We can’t see the future
But we have good predictive power based on current numbers Using birth & death rates, fertility and extrapolation we can model populations into the future Models based on mathematical calculations of future predictions
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Computer Simulations View Population connection simulation
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Demographic Tables
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Projecting Future Populations: Age/Sex Pyramids
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Graphical Extrapolation: World Population
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Review Topics
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Are these characteristics of Developing or Developed Nations?
High fertility rates High consumptive lifestyles: use 80% of world’s wealth Intense poverty Eat high on the food chain Long doubling times High environmental degradation Twenty percent of the world’s population
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Compare Projected Populations in Developing and Developed Countries
Fertility Rate > 2 < 2
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Plumpy nut Life straw
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Consequences of Exploding Populations
deforestation resource depletion loss of agricultural land disease population migration Irrigation biodiversity pest resistance wetlands More Population Causes MORE LESS
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