World Population Objectives

World Population Objectives

• Explore the historical aspects of population growth.

• Define doubling time and explain its meaning.

• Discuss why the population explosion occurred.

• Explain the effects of urbanization.

• Express the need for family planning and describe planning programs.

• Describe ideal population levels.

• Discuss how to manage human environments.

Earth's Age and Human Impact

• The world is approximately 4 billion years old.

• Significant human-caused environmental degradation has occurred, predominantly in the last 2,000 years.

• The need for courses in planet management, ecosystems management, and human environment management is crucial.

• Humans should act as protectors rather than destroyers of the environment.

Historical Population Trends

• For about 300,000 years, overpopulation was not a major issue due to natural checks such as:

  • Drought

  • Floods

  • Famine

  • Plagues

  • Pestilence

  • War

  • Lack of heating and food preservation

• Large families were necessary to ensure the survival of some children.

• Population milestones:

  • Discovery of America: Approximately 250 million people.

  • 1650: Approximately 500 million people.

  • 1850: Approximately 1.2 billion people.

  • 1920: Just under 2 billion people.

  • 1950: Approximately 2.5 billion people.

  • 1980: Approximately 4.5 billion people (more than a fivefold increase in 300 years).

• The world population continues to increase rapidly, with approximately 3 new children born every second.

  • 227,000 per day

  • 83 million per year

Doubling Time

• The world population increase from 1980 to the present is greater than the increase from 1950 to 1980.

• By 2000, there were 21 cities with over 10 million people, mostly in developing countries, along with numerous global urban areas with over 5 million people.

• It is projected that by 2030, global urban populations will double, with developing countries growing by 160%.

• The world population started increasing more rapidly about 200 years ago, which was initiated by the "Great Awakening" followed by the industrial-medical-scientific revolution.

• Advancements in sanitation, immunization, and public health significantly reduced communicable diseases.

• Examples:

  • 1796: Edward Jenner demonstrated smallpox immunization.

  • Walter Reed discovered that the Aedes mosquito spreads yellow fever.

  • Alexander Fleming discovered penicillin.

• Scientists improved flood control, agricultural and food technology, and public and environmental health practices, reducing plagues and epidemics.

• The culture of large families continued, leading to a rapid population growth.

• Doubling time is decreasing, which can be found using growth rate (Table 1.1 and 1.2).

  • The relationship between growth rate and doubling time depends on exponential growth.

Population Increase Potential

• Developing nations have a greater potential for population increase because more females are entering childbearing ages, leading to further population base and growth potential increases.

• Developing countries often have a stair-step or "Christmas tree" graph for population distribution.

• Developed nations exhibit a "stovepipe" effect in population distribution, with fewer children are born in comparison to adults.

Population Explosion

• Microorganisms multiply by simple division (1 to 2, 2 to 4, 4 to 8, etc.).

• If a test tube with organisms that divide every 24 hours is inoculated on day one, it reaches maximum carrying capacity after 365 days.

• The test tube would be half full on the 364th day.

• If one-fourth of the microorganisms die on day 200 or 240, it would take longer to fill the test tube.

• More deaths equate to a smaller population base.

• Throughout history, floods, droughts, famine, war, and disease have decreased the population.

• The bubonic plague pandemic in 430 B.C. and the 1340s each destroyed approximately one-fourth of the world's population.

• Epidemics and pandemics like smallpox, cholera, typhoid fever, malaria, yellow fever, typhus, tuberculosis, and rabies kept the world population in check until recent years.

• Modern knowledge in medicine, public and environmental health, and agriculture have started to control epidemics.

• More unwanted, unplanned babies are living longer, contributing to a human population explosion.

Population Data and Contrasts

• Table 1.3 provides population data for selected countries (2001).

• In 1996, one-third of humanity was under 15 years of age.

• The most populous nations are shown in Figure 1.3.

• The four most populous nations provide a study in contrasts:

  • China: 344 people per square mile.

  • India: 814 people per square mile.

  • Russia: 22 people per square mile.

  • United States: 77 people per square mile.

• Some cultures value large families for:

  • Agricultural labor

  • Military advantage

  • Political influence

  • Religious reasons

Effects of Overpopulation

• In 1791, Thomas Malthus predicted that population would grow faster than the ability to feed it.

  • Populations grow geometrically (2-4-8).

  • Food production increases arithmetically (1-2-3-4).

• Despite agricultural research, one of every three persons in poor, underdeveloped countries cannot find enough to eat and suffer diseases like kwashiorkor (lack of protein).

• Large families often cannot provide for children properly and do not receive necessary services.

• Approximately 12 million people die of starvation each year.

• Thirty million more people each year suffer from diseases worsened by hunger.

• In the hardest-hit areas, the population doubles every 17 to 30 years.

Efforts to Control Overpopulation

• Slogans such as "zero population growth" (ZPG), "Stop at two," and "How dense can we get?" have raised awareness.

• Until about 1984, the U.S. encouraged worldwide population planning and control activities but cut off contributions to UNFPA in 1985 due to pressure from anti-abortion groups.

• Some countries have legalized abortion and offered free sterilization.

• Many countries have educational programs on family planning and the effects of too many children, which have been somewhat effective in developed countries but less so in less-developed countries (LDCs).

• Overpopulation causes undesirable environmental, social, economic, educational, and political problems.

• Increased technology, a desire for affluence, and a growing population contribute to environmental degradation.

• Refusal to manage effluent from affluent society leads to:

  • Noise pollution

  • Hazardous waste

  • Air pollution

  • Water pollution

  • Land pollution

  • Ozone depletion

  • Crowded, dirty cities

Urbanization

• In 1800, approximately 6% of the U.S. population lived in urban areas; now, over 73% do.

• Worldwide, approximately 28% lived in cities in 1950; by 2020, more than 66% are expected to.

• As families produce more children than they can support, the children migrate to cities in search of work.

• Computer-operated machinery and modern technology reduce the need for manpower, leading to unemployment, drug addiction, alcoholism, crime, and homelessness.

• In some developing country cities, babies are born, live, and die in the streets.

• Much of the population growth results from unplanned and unwanted pregnancies.

• Many cities do not provide shanty towns and slums with adequate drinking water, sanitation, food, health care, housing, schools, and jobs.

• In 1994, the world's biggest cities were growing by one million a week.

• Figure 1.4 shows the largest urban agglomerations in the world.

The Need for Family Planning

• A high percentage of babies born each year are unwanted.

• Many children are born into large families that cannot provide a good quality of life.

• Unwanted babies exacerbate economic, social, and environmental problems.

• John D. Rockefeller, III, stated that population growth intensifies many problems and that a moral consensus is fundamental to addressing the population problem.

• Preventing unwanted pregnancies is crucial.

• Developed nations need to help their own people and those in less-developed countries to prevent unwanted babies through parent education programs.

• Reducing the number of unwanted babies could alleviate overcrowding and many other related problems.

• A family planning program should be available worldwide.

• Parents should be able to have only the number of children they want.

• Planned Parenthood programs focus on family planning and economic growth to decrease birthrates.

• By 1986, programs to reduce birth rates were available to 91% of the population of less-developed countries.

• Effectiveness and funding vary by country.

• President Lyndon B. Johnson: "Five dollars spent on population control is equivalent to one hundred dollars in economic growth."

• Economic development may reduce desired family size by enhancing education, providing economic security, and reducing reliance on children for old-age support.

• Family planning services provide guidance in regulating family size and health.

• Table 1.4 lists common methods of preventing pregnancies (progestational agents).

Ideal Population Levels

• Dr. Theodore Morgan and other ecologists believe the world population will grow until the quality of life is degraded for all.

• Some ecologists believe a "super" world agency will be needed to set and enforce ideal population levels.

• Ideal population levels may be determined by factors such as per-capita income, quality of life, length of growing season, topography, waste disposal facilities, size, technology level, and air and water quality.

• Even if optimum population levels are determined, enforcement will be difficult.

• Population control could be influenced by:

  • A "super agency"

  • Air pollution

  • Water pollution and disease

  • Toxic materials

  • Lack of food

  • Lack of space

  • War

• Controlling population through family planning is preferable to starvation.

Managing Human Environments

• The biosphere's size remains constant, but the population and its desires have increased.

• With more people living longer and demanding more resources, greater demands are placed on the environment.

• The two primary areas of demand are:

  1. Providing resources for a growing population.

  2. Disposing of effluent from the population.

• Solutions may be found in:

  1. Family planning services to prevent unwanted babies.

  2. Worldwide environmental management for a sustainable society.

Summary

• The earth's population is approximately 6.2 billion and increasing at about 83 million per year, necessitating careful planning and management.

• Developing countries have greater potential for population growth due to current health problems with infectious diseases such as malaria, yellow fever, typhus, and tuberculosis.

• Two broad approaches to managing human environments are:

  • Family planning.

  • Environmental management (controlling agents that cause disease).

Key Terms

• Biosphere, p. 12

• Growth rate, p. 2

• Doubling time, p. 2

• ZPG, p. 7

Equations

• Doubling Time Td can be calculated using the growth rate r with the following formula: Td = {\ln(2)}{\ln(1+r)} or approximately T_d \approx {70}{r\%}, where r is the annual growth rate.