Human Population: Growth, Demography and Carrying Capacity

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Human Population Growth, Demography and
Carrying Capacity
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Human Population Growth Historical Perspectives

• Early Hunter Gatherers
• Nomadic - strong sense of the Earth
• Practiced intentional birth control
• Rise of Agriculture
• Animals became extinct via predation and altered
  habitat
• Agriculture gave rise to cities
• Food became a commodity produced in the country,
  consumed in
• the city
• Food wastes no longer returned to the soil
• Soil becomes less productive
• Waste becomes concentrated in cities

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MI L L I O NS
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Current World Population

• Population Clock Vital Events (per time unit)
• Global population was 6,662,712,508
• On November 8, 2006 at 1200 am
• The global population grows by
• Nearly 2.3 persons per second
• Nearly 8,343 persons per hour
• Over 200,234 persons per day
• Over 73 million persons per year

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How Much is a Billion?

• 1,000 seconds 16.7 minutes
• 1 million sec 16,677 min 11.6 days
• 1 billion se 11,574 days 31.7 years
• 1,000 pennies 88 ounces 5.5 pounds
• 1 million pennies 5,500 pounds (1 Suburban)
• 1 billion pennies 2,750 tons (2 Space
  Shuttles)

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Human Population Dynamics

• Three sources of change in population size
• Fertility
• Mortality
• Migration
• A "natural decrease" refers to population decline
  resulting
• from more deaths than births
• Net migration is number of immigrants - number of
  emigrants
• The rule of 70 gives a good estimate of the
  time needed for
• a population to double in size (e.g., 2 growth gt
  70/2 35
• years to double)

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Fertility

• Total fertility rate (TFR)
• The average number of children born to a woman
• TFR in the U.S. reached its peak in the mid-1950s
• Current average in developed countries 1.5
• Current average in developing countries 3.8
• Worldwide 1990 3.1 2004 2.76
• Replacement fertility rate (RFR)
• The number of children a couple must have to
  replace themselves
• World wide, the RFR is just above 2
• The birth rate in the U.S. has been at or below
  replacement level for about 28 years

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Immigration

• Most countries restrict immigration
• Canada, Australia and the U.S. are the countries
  with the most immigration
• In 2002, legal and illegal immigration accounted
  for 40 of the population growth in the U.S.
• Involuntary immigration results from
• armed conflict
• environmental degradation
• natural disaster
• 1 of developing nations population are
  emigrates
• Migration is also occurring from rural to urban
  areas

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The Population Paradox

• While the population of many industrialized
  nations is aging, the same is not true in
  developing nations
• In 2004, 30 of the worlds population was under
  the age of 15
• China Indias population combined is 38 of the
  global population
• The U.S. is next, with 4.6 of the population
  (300 million)
• The impact on the earths resources can be
  summarized in the following equation I P x A x
  T
• I impact on the environment
• P population (human)
• A affluence
• T technology

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Global Inequities

• Basic needs are not available for 1 in 6 people
  today
• More than 1 billion people survive on less than
  one dollar per day nearly 3 billion people live
  on less than 2 a day
• Situation has worsened since 1980
• The richest 20 of the world
• Consume 45 of all meat and fish
• Consume 58 of total energy
• Have 74 of all telephone lines
• Consume 87 of all paper
• Own 87 of the worlds vehicles
• Worldwide, over 45,000 people die each day of
  starvation, 38,000 of them children

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Wealth Gap U.S.

• Even in the U.S., the wealth gap has grown
  significantly
• The gap between the per capita GNP of the rich,
  middle-income and poor has widened
• Of all the high-income nations, the US has the
  most unequal distribution of wealth
• The richest 1 of Americans combined earned as
  much after taxes as the poorest 100 million
  Americans combined (1999)
• Read Nickel Dimed to see what it is like to
  live on the Federal minimum wage

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Family Planning Goals Reduce Births and
Abortions

• Overall contraceptive use is up from 10 in the
  1960s to 46 in 2004
• FP is responsible for at least 55 of the drop in
  the Total Fertility Rate in developing countries
• FP reduces children's social services needs
• FP reduces risk of childbearing deaths
• FP effectiveness depends on program design and
  funding

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Family Planning Goals Reduce Births and
Abortions

• FP has reduced both legal and illegal abortions
• Women often want to limit their pregnancies but
  have no access to contraceptives
• Services not always accessible to female
  teenagers and sexually active unmarried
  individuals
• In some places includes birth control for men
  (sperm-killing device used in China)
• If developed countries provided 17 billion/year,
  and each person paid 4.80/year, the average
  family size would be 2.1 and world population
  would be 2.9 billion
• Issues with U.S. policy in developing countries

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Empowering women to reduce births

• Women tend to have fewer and healthier children
  when
• they have access to education and paying jobs
  outside home
• their society doesnt suppress womens rights
• Women own less than 1 of the worlds land
• Women do most of the work, however
• they receive only 10 of the worlds income (in
  the U.S., women earn 0.77 for every 1.00 earned
  by men, data from 2002)
• are excluded from economic and political decision
  making (women make up 51 of the U.S. population
  and less than 25 of U.S. senators,
  representatives, state governors and Federal
  judges)