Copy of Notes - Human Population and Demographics

Overview of Human Population

  • The Earth is seen as a living organism affected by rapid human population growth.

Early Human History

  • Initial population was low, existing as hunter-gatherers.

  • Population limited by environmental factors: food, water, predators, disease.

Migration and Agriculture

  • 130,000 years ago: Homo sapiens migrated from Africa.

  • The Fertile Crescent had high biodiversity and was pivotal in agricultural development with:

    • Eight "founder crops" (e.g., flax, wheat).

    • Ancestors of four major livestock species.

  • Development of irrigation due to two major river systems noted.

  • This shift marked the Agricultural Revolution: Move from nomadic to settled lifestyles, increasing food control and population growth.

Population Growth from Middle Ages to Industrial Revolution

  • By 1800 CE, human population reached around 800 million.

  • Density-dependent limiting factors included:

    • Famines (e.g., Western Europe 400-800 CE, Great Potato Famine).

    • Diseases (e.g., malaria, Black Plague).

Industrial Revolution (1760-1840s)

  • Technological advancements led to significant healthcare improvements:

    • Introduction of antibiotics, vaccines, water treatment.

  • Resulted in a massive drop in infant mortality and an increase in life expectancy:

    • Pre-industrial life expectancy in Britain: 25-40 years.

    • Current worldwide: 68-73 years.

  • Industrialization spurred exponential population growth.

Exponential Growth Analysis

  • Population growth accelerated with:

    • Time taken to reach 1 billion: 70,000 years.

    • Rapid growth to 7 billion in just 11 years.

  • Doubling time reduces as growth accelerates.

Human Demography

  • Demography involves analyzing births, deaths, gender, race, economic status.

    • Developing countries: younger, poorer, faster growth.

    • Developed countries: older, wealthier, potential decline.

  • Demographic characteristics such as:

    • Life expectancy, total fertility rate (TFR), and GDP per capita play critical roles.

Population Projections

  • Population growth distribution varies; migration trends impact demographic statistics.

  • Developed countries often counter declining populations through immigration.

Population Pyramids

  • Understanding gender and age distributions via population pyramids is essential for making demographic projections.

  • The shape provides insights into growth rates and potential future trends.

Demographic Transition Model

  • Stages of Demographic Transition:

    • Stage 1: High death and birth rates.

    • Stage 2: Decreasing death rates; high birth rates.

    • Stage 3: Birth rates fall; population growth slows.

    • Stage 4: Birth rates drop below replacement level; population decline.

Future Population Trends

  • Projections suggest stabilization of world population within the century, estimating:

    • Low: 8 billion

    • Medium: 9.3 billion

    • High: 13 billion.

Impact of Population Growth on Natural Capital

  • Human growth affects ecological footprint and cultural carrying capacity.

  • Degradation of natural capital includes:

    • Loss of biodiversity, increased genetic resistance, reliance on fossil fuels.

    • Notably, altering natural systems to meet human needs.