Chapter 16, Section 2

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Chapter 16, Section 2

• World Population

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The Problem of Population Growth

• World population figures are a composite of best
  estimates and national census figures
• The quality of census data varies and can be very
  unreliable
• Rapid world population growth is a relatively
  recent phenomena

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The Problem of Population Growth

• The worlds population is expected to reach 8
  billion persons by the year 2025
• The number of years between each doubling of the
  population is called doubling time and is getting
  shorter and shorter
• Population increases exponentially

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Malthus and Population Growth

• In 1798 Thomas Robert Malthus published an essay
  describing relationships between population
  growth and economic development
• Population, if left unchecked, will exceed the
  food supply
• Checks on population can be positive or preventive

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Malthus and Population Growth

• Positive factors are events or conditions that
  increase mortality
• Famine, disease, war
• Preventive factors decrease fertility
• Sexual abstinence, marrying at a later age
• For the poor, any improvement in income is eaten
  up in additional births
• The wealthy and well educated already exercise
  preventive checks

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Malthus and Population Growth

• Believed that positive checks could be avoided
  through education of the poor
• With education the poor would raise their
  standard of living and choose to have smaller
  families

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The Demographic Transition

• The demographic transition theory looks at the
  stages of economic development in a country to
  make predictions about population growth
• Considers two things Malthus did not predict
• Agricultural productivity
• Reliable methods of birth control

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The Demographic Transition

• Demographic transition theory describes four
  stages of population growth
• Both the birth rate and the death rate are high
• The birth rate remains high, but the death rate
  drops sharply
• The birth rate declines sharply but population
  growth is still rapid because the death rate
  continues to go down
• Both birth rate and death rate are low and the
  population grows slowly if at all

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Future World Population Growth

• The annual population growth rate is declining
• The current growth rate is 1.3 compared to 2.04
  in the late 1960s
• However, the worlds population will continue to
  increase
• The annual growth rate is expected to decline
  until world population stabilizes
• Zero population growth deaths are balanced by
  births so the population does not increase

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Future World Population Growth

• Limiting the average family size does not
  immediately produce zero population growth
• Population momentum

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Population Control

• Death rates in the world have already dropped
  dramatically
• Population control refers to the conscious
  attempt to regulate population size through
  national birth control programs
• Voluntary use of population control methods is
  known as family planning

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Population Pyramids

• Population pyramids allow you to see at a glance
  the age and sex composition of a population
• Illustrate the dependency ratio that results from
  different rates of population growth
• Two aspects of the dependency ratio
• Youth dependency
• Old-age dependency

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Population Pyramids

• Developing nations have much higher youth
  dependency than developed nations
• High youth dependency means that national income
  must be diverted from economic development to
  provide food, housing, and education for its
  large young population
• Developed nations have higher old-age dependency

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Population Pyramids

• Rising old-age dependency creates many problems
• There are fewer young people in the labor force
  to support the growing number of older people
• The shift in the US increases the burden put on
  the young to pay for Social Security and Medicare
• The need for increasing health care services and
  institutional arrangements for the long-term care
  of elderly people

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Assignment

• Section 2 Assessment (p. 546) 1-4