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ESC110 Chapter 4. Human Populations. Some Topics Discussed. Population growth Limits to growth Human demography Demographic transition Family planning and fertility control The future of human populations. Population Growth. World population now over ?? billion. Population = Pollution??.
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ESC110 Chapter 4. Human Populations Some Topics Discussed • Population growth • Limits to growth • Human demography • Demographic transition • Family planning and fertility control • The future of human populations
Population Growth World population now over ?? billion
World pop: • 2003 = 6,271,470,983 • 2004 = 6,345,338,406 • 2005 = 6,413,322,261 At 9AM Jan 18 • US pop: • 2003 = 290,131,722 • 2004 = 292,484,293 • 2005 = 295,279,623 At 9AM Jan 18 1 birth every 8 secs 1 death every 13 secs 1 intnl migrant (net) every 26 secs 1 NET person every 12 secs http://www.census.gov/main/www/popclock.html
Current Birth and Death Rates • Every second: 4 or 5 children are born, while 2 other people die • Net gain: 2.5 humans added to the world population every second • 78 million added every year
Population Growth N Amer Latin Am & Carib Europe Asia & Oceania Africa World Resources 1998-99
P x A x T Environmental Impact = P = population density A = affluence T = technology
P = number of people A = affluence or average resource-use per person T = technology or the beneficial & harmful environmental effects of the technologies used to provide & consume each unit of resource
Projected Population Growth N Amer Latin Am & Carib Europe Asia & Oceania Africa
Stabilization ratio = crude birth rate/crude death rate S&C Amer Africa Dev’g Asia Dev’d
Limits to Growth Varying Perspectives • Overpopulation causes resource depletion and environmental degradation • Human ingenuity and technology will allow us to overcome any problems - more people may be beneficial • Resources are sufficient to meet everyone's needs - shortages are the result of greed, waste, and oppression
Decisions on how many children to have are influenced by many factors, including culture, religion, politics, need for old-age security, and immediate family finances.
Human Demography • Demography - vital statistics about people, such as births and deaths Two demographic worlds • Less-developed countries represent 80% of the world population, but more than 90% of projected growth • Richer countries tend to have negative growth rates
By 2050, India will probably be the world’s most populous country.
Fertility and Birth Rates • Fecundity - physical ability to reproduce • Fertility - the actual production of offspring • Crude birth rate - number of births per year per thousand people • Total fertility rate - number of children born to an average woman during her reproductive life • Zero population growth (ZPG) – occurs when births + immigration = deaths + emigration
Population Growth -Opposing Factors Pronatalist pressures • Factors that increase people’s desires to have children (eg, enjoy family, help earnings, high death rate, help when older, males valued, male pride, etc) Birth reduction pressures • Factors that tend to reduce fertility (eg, educated women & careers, higher family earnings, etc)
Demographic Transition • Optimistic view - world population will stabilize during this century • Pessimistic view - poorer countries of the world are caught in a "demographic trap" - helping poor countries will only further threaten the earth's resources • Social justice view - overpopulation due to a lack of justice, not resources
Birth Control Methods Family Planning
The Future of Human Populations U.N. Projections
Summary: • Population Doubling Times • Role of Technology • Two Demographic Worlds • Fertility and Birth Rates • Mortality and Death Rates • Population Growth Factors • Demographic Transition • Future of Population Growth