Population and Society 4 Major Causes of Environmental Change



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Population and Society

4 Major Causes of Environmental Change

  • Population change
  • Institutions
  • Attitudes, values, belief systems
  • Technological change

Carrying Capacity

  • The maximum number of organisms an environment can support.
  • But highly dependent on technology, there is no set carrying capacity, technology increases production

Thomas Malthus (1766-1834)

  • An Essay on Population (1798).
  • Wrote at beginning of the 19th century, when population growth and industry were raising demands for food faster than English agriculture could respond.
  • Human population would always increase exponentially (the larger it gets the faster it grows) while the supply of food and land would only increase “arithmetically” (additively)
  • Scarce farmland
  • Overuse of resources
  • Poverty and human misery
  • Each increase in food supply only meant that more people could live in poverty

Cultural Carrying Capacity

  • “There should be no more people in a country than could enjoy a daily glass of wine and a piece of beef for dinner.” --Thomas Malthus
  • Cultural carrying capacity is smaller
  • than simple carrying capacity.

World Population Growth Rates

  • Population growth rates measured by annual increase in a country’s population are highest in
  • Africa and Middle East. Growth rates are flat in U.S., Europe, and former Soviet Union

World Population Growth Doubling Time

  • 1800-1850 1 billion
  • 1930 2 billion
  • 1960 (30 years) 3 billion
  • 1974 (14 years) 4 billion
  • 1986 (12 years) 5 billion
  • 1999 (13 years) 6 billion
  • The current increase of the Earth’s human population in either absolute or relative terms, vastly exceeds the average increases over most of human history.
  • Nobody saw this coming.
  • In 1936 demographers predicted that the world population 2.645 billion people by the end of the 21st century (we hit that by 1955).
  • 1950 estimate 3.3 billion by 2000 (off by 50%.)

World Population Growth

  • Growth rate was at all time peak of 2.1% between 1965-1970 (The Population Bomb by Paul Ehrlich, 1968).
  • Predicted "in the 1970s and 1980s and 1980 hundreds of millions of people will starve to death", that nothing can be done to avoid mass famine greater than any in the history, and radical action is needed to limit the overpopulation. ( a neo-Malthusian position)
  • The growth rate has since declined to about 1.2% per year.
  • Global fertility rates are falling: from 5 children per woman per lifetime in 1950-55 to 2.7 children in 2000-2005
  • Absolute annual increase in population peaked around 1990 at 86 million and has fallen to 77 million.
  • In 1960, five countries had total fertility rates at or below the required level required to replace the population in the long run.
  • By 2000 there were 64 such countries with 44% of world population

Beginning-High Birth rates, high death rates

  • Beginning-High Birth rates, high death rates
  • Transition-High birth rates, low death rates (By 1900, life expectancy at birth was 40-50 years, today it is 78 years for women and 71 for men and rising rapidly).
  • Third Stage-low death rates, low birth rates
  • The Demographic Transition Model

Why has the world’s population increased by so much?

Demographic Transition Continued What makes the death rate decrease?

  • Increased productivity: agriculture can support larger populations than before
  • Advances in the control of epidemic diseases and improvement in public health, death control: antibiotics, biocide DDT to control insect vectors of infection, vaccines against smallpox, measles, whooping cough, and drugs that cured tuberculosis and malaria

Demographic Transition Continued What makes the birth rate decrease?

  • As people become urbanized children go from being an economic asset, to becoming an economic burden
  • Cultural norms that encouraged a women to have large numbers of children weakened.
  • Increasing opportunities for women: low status of women=economic dependence and higher birthrates.

The Six Commandments of Population Control

  • 1. Promote Contraceptives.
  • 2. Develop Economies
  • 3. Save Children
  • 4. Empower and Educate Women
  • 5. Educate Men
  • 6. Do all of the above

The Population Debate

  • Neo-Malthusian: our capacity to produce food cannot keep up with our reproductive capacity.
    • Population growth is a severe threat
    • There are limits to the physical capacity of the planet to sustain growth
    • Population growth is also a major cause of environmental degradation

Explaining World Hunger

  • Agricultural modernization perspective argues that the world hunger problem is caused by not enough food produced by traditional agriculture
  • Another major factor lies not in the quantity of food, but the distribution of food.

Where is most population growth in the US from?

  • According to the census bureau, post-1970 immigrants and their descendents will account for over 80% of US population growth between now and mid 21st century.

Migration: Population Growth in the US

  • 1994: US Commission on Immigration Reform declared: “We disagree with those who would label efforts to control immigration as being inherently anti-immigrant. Rather it is both a right and a responsibility of a democratic society to manage immigration so it serves national interest.”

Population growth in the US

  • According to surveys by the Wall Street Journal and the Latino National Political Survey: Clear majorities of African Americans and Latinos favor reductions in legal and illegal immigration.

The Politics of Population

  • 1974: The First UN Conference on Population
  • Developing countries rejected the Neo-Malthusian position, that poor countries are poor because of overpopulation.
    • Instead, poverty causes overpopulation.
    • Redistribution of wealth is needed.
    • Birth control vs. wealth control
  • Today, many developing countries are actively trying to limit population.
  • China’s one child policy

Today’s World Population

  • World POPClock Projection
  • According to the International Programs Center, U.S. Bureau of the Census,
  • http://opr.princeton.edu/popclock/

Will Malthus always be wrong? Current Declines in World Population Growth Rate

How Big will the Population Get? Trends

  • The global total fertility rate fell from 5 children per woman per lifetime in 1950-55 to 2.7 children in 2000-2005.
  • Absolute annual increase in population peaked around 1990 at 86 million, and more recently is at 77 million
  • 64 countries with 44% of total population now have fertility rates below those needed to replace population

More Trends

  • More than half of the annual increase currently occurs in six countries: India, China, Pakistan, Bangladesh, Nigeria, and the US (but US only 4%).

Population Growth Scenarios

  • Fertility at current levels= 12.8 billion by 2050.
  • Medium projection-8.9 billion by 2050 assumes family planning efforts will continue and suceed, fertility continues to drop..
  • Most optimistic prediction7.066 billion
  • More than half of annual increase in six countries: India, China, Pakistan, Bangladesh, Nigeria, and the US (mostly from immigration)

Will Food Production Keep Up? Will Malthus always be Wrong?


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