POPULATION - LECTURE NOTES

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Introduction

• World population situation in a nut shell.
  • On the face of the earth are approaching a population of 6 billion people
  • Over 1/3 of the individuals are under the age of 15.
  • Thus, billions of individuals are just coming into their most fertile reproductive age range.
  • Numbers of people, represent power/influence. In other words, the more people in your army, organization, etc., the more power/influence you have.
• Consequences
  • The question is what force(s) will bring the worlds population growth rate under control?
  • Nature?
  • Humans?
  • To date we have not acknowledged a need to do so.
• Strong feelings polarize individuals
  • One side feels that people are a natural resource and the crisis is an economic and political one. A second group involves religious groups, who contend that any proposals related to artificial birth control and abortion are counter to their religious beliefs, an example is that they undermine traditional family values.
  • at the opposite pole are those who feel that indeed there is a crisis and we must bring it under control quickly.
• Goal
  • My goal, during this hour, will be to bring to your attention the facts, relative to population growth, as I have been able to discern them.

Numbers of People

• The 1st billion
  • Number of years
    • occurred somewhere around yr. 1850 (approximately 150 years ago)
    • depending upon which anthropologist or archeologist book you read, estimates range from 250,000 to two million years-
  • Significant milestones
    • Agricultural revolution
      • For that time period (up to two million years) humans hunted and gathered food. The population of earth probably never exceeded 5-10 million people. Estimations based on densities of hunting and gathering tribes indicate that the population probably never exceeded 5 to 10 million people.
      • Between 8,000 and 6,000 BC humans learned to grow their own food-momentous change-- humans could support vastly larger numbers. Resulted in clusters, settlements, villages, etc. eventually cities.
      • Increasing portion of earth's biomass devoted by humans. to humans
    • Take off point
      • occurred somewhere around 1650
• The 2nd, 3rd, and 4th billions
  • 2nd billion - 80 years 1930
  • 3rd billion - 30 years 1960
  • 4th billion - 15 years 1975
  • 5th billion - 11-14 years 1986-90
• Perspective of current expansion rate
  • World
    • Every day add approximately 200,000 to the worlds population.
  • U.S. 6300 per day (2,000 from immigration)
• Future projections
  • The current growth rate will continue in immediate future
    • in less than 25 years:
      • Africa will have to accommodate 535 million more people.
      • Lat. Am. 440 million
      • Asia 2+ billion
  • Now Africa, Latin America, and Asia have 11, 8, & 58% of the worlds population, respectively.
    • current growth rate can't continue over a long period of time.
    • 500 years: - 1 person/sq. yd of land area
    • 1000 years: - 5100 people/sq. yd of land area and we'd be expanding outward at the speed of light

Demographic terms

• Births and Death rates
  • crude birth rate - total live births per 1000 people
  • crude death rate - total deaths per 1000 people
• Growth rate
  • growth rate - represents the difference of the two
  • + immigration ÷ beginning pop
  • example: U.S. 91 pop growth = 4 million births-2.1 million deaths + 725 K (.725 million) net migration/250 million.
  • Thus, beginning population U.S. 1992 ~253.6 million

Recent major demographic trends

• Decline in death rates in countries undergoing industrialization.
  • Began in 1600's - slow till 1800's - accelerated in mid-1800's through 1900
  • Characterized by a group of transformations internal origin which together resulted in the industrial revolution.
    • Industrialization resulted in urbanization. The transformations included advances in:
      • Education
      • Agricultural Mechanization
      • Transportation
      • Public Health
• Decline in birth rates following industrialization -Why?
  • Agrarian Society - children economic asset - I.E. extra hands on farm and old age insurance for parents.
  • Urban Industrial Society - children are consumers. Thus, to certain extent economic liabilities particularly in city and to some extend on farm Cost of raising one urban child to age of 18 was estimated to be between $125,000 to $150,000.
• Dramatic decline in death rates in underdeveloped countries - around the time of WW II
  • primarily due to export of modern drugs and public health measures.
  • major point to remember - drop in death rate rapid; major force (a humanitarian one) originated outside their boundaries and was not accompanied by a change in their social or economic structure which would result in a drop in birth rates.

Population growth factors

• more to population than sizes and growth rates
• population have structure - most important factor is composition or age makeup of population - usually by 5 yr.... intervals.

  

• Numbers of people in age groups (age structure diagrams or population histograms)
  • Replacement fertility level - the average number of live births necessary for the producing population to replace itself.
  • It ignores effects of immigration and in U.S. this figure is 2.11 (women age's 15-44)
    • -2.1 because infant mortality of females and fewer females born than males
    • < age 5 males- 104.7 to 100
    • > 65 67.6 to 100 females.
    • fact - U.S. below replacement fertility rate yet we continue to grow
    • a population does not cease to grow until birth rates equal death rates -- Zero Population Growth (ZPG)
• Factors which influence future population growth in the US
  • Number of women in child bearing age group and their fertility rate
  • Desired family size
    • Education
    • Contraceptive technology and availability
    • Age of marriage
    • Economic environment
    • Traditions
  • Net migration
  • Longevity
• Future
  • Effect of immigration
  • Effect of all factors

Dr. Don Stucky's class notes. Last revised 7/9/97.