Human Population - Lecture

Tragedy of the Commons

  • Process by which publicly open resources are dumped and/or overused

    • depleted —> ecological footprint

      • ex: Easter Island, Greek and Roman Empire

        • forests, air, water, soil

Population Growth

  • How Do We Use Less With a Growing Population?

    • It took nearly 200,000 years for humans to reach 1 billion people

    • It took only 100 years to go from 2 billion to 7 billion people

  • Doubling Time

    • Rule of 70:

      • 70/% Growth

  • Population Bomb - 1968

    • Paul Ehrlich: predicted civilization would end by end of 20th century

      • wrong due to technology and intensified food production

  • Population Impact: IPAT

    • I (impact): population x Affluence x Technology x Sensitivity

Population Demographics

  • Population size

    • doesn’t tell whole story

  • Density and Distribution

    • high density: found near water, large cities, urban sprawl

    • low density: extreme environment

  • Age Structure:

    • relative numbers in each age

      • wide base: high reproduction, rapid population growth

      • bullet: stable, even age distribution

      • narrow base: decline in population

  • Sex Ratio

    • females vs males

  • Fertility Rates

    • how populations change

      • TFR: total fertility rate

        • number of children born

      • replacement fertility: TFR that keeps population stable

    • CNA: 1.9, Africa: 4.7

  • Birth vs Death Rates

    • Birth - Immigration

    • Death - Emigration

  • Other Factors That Change Populations

    • Affluence, education, technology, war environmental degradation, industrialization

Key Approaches to Population Control

  • Family planning, birth control, empowering women (education) affluence

Demographic Transition

  • Model of economic and cultural change

    • explains declining death and birth rates in industrialized nations

  • Four Styles

    • 1. Pre-Industrial

      • birth and death rate high

    • 2. Transitional

      • decreasing death due to medical care and food production

    • 3. Industrial

      • birth rates fall due to education of women

    • 4. Post-Industrial

      • low and stable birth and death rates