Human Population Growth

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Human Population Growth
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Factors Affecting Human Population Size

• Births
• Deaths
• Migrations
• Immigration individuals moving into a pop.
• Emigration individuals moving out of a pop.
• Population Change
• (birthsimmigration)-(deathsemigration)
• When births and immigration is greater than
  deaths and emigration, the population will
  increase
• http//www.youtube.com/watch?v4BbkQiQyaYc
• http//www.youtube.com/watch?vsc4HxPxNrZ0feature
  related

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World Population

• Rate of annual pop change is expressed as a
  percentage birth rate-death rate 10
• The U.S. had a birth rate of 14.6 live births per
  1,000 population in one year, compared to Indias
  birth rate of 22.2 in that same year. The death
  rate in that year for the U.S. was 8.3 deaths per
  1,000, compared to Indias rate of 6.4.
  Calculate the population growth rates () for
  both countries.
• U.S. 14.6-8.3 0.6 10
• India 22.2-6.4 1.6 10
  
  

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World Population

• Exponential growth has not disappeared, but its
  occurring at a slower rate
• Between 1963 and 2002, the population rose from
  3.2 to 6.2 billion
• 79 million people were added in 2002, compared to
  69 million in 1963 when the worlds pop growth
  rate was at its highest

5
Human Population Growth over Time

• Before agricultural revolution 1-3 million
  humans, hunter/gatherers, Earth Wisdom-natural
  cycles serve as models for human behavior
• 8000 BCE-5000BCE 50 million humans, increases
  due to agricultural revolution
• 5000 BCE-1 BCE 200 million humans, Frontier
  Worldview-undeveloped land as a hostile
  wilderness to be conquered, exploited resources
• 0 BCE-1300 CE 500 million humans
• 1300-1650 CE 600 million humans, plagues
  reduced population growth rate

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Human Population Growth over Time

• 1650-present 7 billion humans, reductions in
  death rates, increase medical technology,
  Planetary Management-as we are the planets most
  important species, we are in charge of earth, we
  will develop new resources so should not worry
  about using them sustainably
• Present-2050 9 billion (?), Earth
  Wisdom-resources are limited so should be
  conserved, we should encourage sustainable use of
  resources because the earth exists for all nature

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Fertility Rates

• Replacement Level Fertility- of children that a
  couple needs to have in order to replace
  themselves (2.1 in developed countries/2.5 in
  developing countries)
• Total Fertility Rate (TFR)-an estimate of the
  of children a woman will have during childbearing
  years (based on the previous year)

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United States Historical Trend in Total Fertility
Rate

• 1910-1930 birth rates dropped due to
  urbanization
• 1930s stayed low because of the Great
  Depression
• 1940s rising again
• 1957 TFR3.7 children/woman, highest
• 1946-1964 Baby Boom
• 1965-1977 Baby Bust
• 1977-2000 Echo Boom

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United States Historical Trend in Total Fertility
Rate
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Factors that Affect Average Birth Rate and TFR

• Children are part of the labor force-
• Urbanization-
• High cost of raising and education children-
• High infant mortality rate-
• Older average age of marriage-

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Factors that Affect Average Birth Rate and TFR

• High availability of pension systems-
• Availability of legal abortions-
• Availability of birth control-
• Men included in child-rearing responsibilites-
• Religious beliefs, traditions, cultural norms

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Factors That Decrease Death Rates

• Increased food supply and distribution
• Better nutrition
• Medical improvements
• Increased sanitation
• Better water supply

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Two Indicators of Overall Health

• Life expectancy average of years people live
• Global life expectancy 76 in developed
  nations/65 in developing nations
• US 77 yrs.
• Africa 55 Yrs.
• Infant Mortality Rate of babies out of 1000
  that die before their first birthday
• High infant mortality rate indicates insufficient
  food, poor nutrition, high incidence of
  infectious disease (water supply)

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Infant Mortality Rates
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Population Age Structure

• The proportion of the pop of each sex at each age
  level used to make pop and economic projections
• Age levels
• Prereproductive (0-14)
• Reproductive (15-44)
• Post reproductive (45 and up)
• Age structure affects population growth
• Countries with a wide base (lots of people below
  15) will increase in size if death rate stays the
  same

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Population Age Structure
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Population Study-Example

• Social security crisis

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Populations Affected by Immigration

• U.S.
• Canada
• Australia

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Cultural Carrying Capacity

• Different from actual of individuals an area
  can support b/c of culture when land is used to
  grow feed for cattle it expends more energy thus
  reducing carrying capacity
• Eating high on the food chain uses up to 50x more
  land than eating a vegetarian diet
• 43 of U.S. is used for grazing or feed for
  livestock meats impact on the environment is
  second only to automobiles

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Demographic Transition

• Demography study of human population
• As countries become industrialized first death
  rates, but then birth rates decline
• Four Stages
• Preindustrial Stage
• Tansitional Stage
• Industrial Stage
• Postindustrial Stage

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Preindustrial Stage

• Little population growth because of harsh
  conditions
• High birth AND death rates

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Transitional Stage

• Population grows rapidly when industrialization
  improves
• High birth rates, lowering death rates
• Stage that developing nations are in currently

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Industrial Stage

• Population growth slows as birth rates drop and
  eventually approach death rates

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Postindustrial Stage

• Birth ratedeath rate
• Zero population growth
• U.S., Japan, Europe (some populations are even
  decreasing)

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Demographic Transition
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India

• 1.1 billion people
• 16 of worlds people, but only 2.3 of worlds
  land resources and 2 of worlds forests
• 70 of water seriously polluted
• Tried family planning, but not very successful
• Why?

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India
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China

• 1.3 billion people
• Since 1970, cut its crude birth rate in half and
  decreased TFR from 5.7 to 1.8 children/woman
• How?
• Free sterilizations/contraception/abortions
• Couples who have only one child receive extra
  food, larger pensions, better housing, free
  medical care, salary bonuses, free school tuition
  for their child, and preferential treatment in
  employment when their child enters the work force

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China

• Projected that Chinas pop will begin to decline
  in 2042, but what about their aging
  population/social security?
• Should other countries impose such severe
  restrictions/limitations on human freedoms to
  achieve pop control?

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China
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Cutting Global Population Growth

• Provide access to family planning services and
  reproductive health care
• Improve health care of infants, children,
  pregnant women
• Implement population policies
• Improve job opportunities for women
• Increase access to education, especially to women
• Increase involvement of men in child-rearing
• Eradicate poverty
• Reduce/eliminate unsustainable patterns of
  production and consumption

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Cutting Global Population Growth

• Goal of Cairo Commitment stabilize pop growth
  at 7.8 billion by 2050 instead of projected 9-11
  billion
• BTW we are already at 6.7 billion..
• World Clock

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World Population