AP Human Geography: Population Growth & Decline Notes
Global Population Trends
- Historical Growth:
- 1800: 1 billion people (after 40,000 years of human existence)
- Present: 8.3 billion people (rapid growth in the last 200 years)
- Current Trend: Overall global growth rate is declining.
Measuring Population Growth
- Crude Birth Rate (CBR): Number of live births per 1,000 people per year.
- Example: A CBR of 20 means 20 births for every 1,000 people in a year.
- Total Fertility Rate (TFR): Average number of children a woman will have in her lifetime.
- Historically high (around 6) due to high child mortality.
- Currently around 2.1 globally.
Factors Influencing TFR
- Development Level:
- Developed countries: TFR generally below 2.1 (e.g., US - 2, Japan - under 2).
- Developing countries: TFR generally higher (4-6 or more).
- Industrial Revolution: Led to increased food production, lower death rates, and eventually lower TFRs in Europe.
- Women’s Education and Empowerment:
- Increased education and workplace equality correlate with lower TFRs (e.g., Japan).
- Example: Between 1990-2007, TFR in developing nations dropped significantly as female education levels rose.
- Economic Development: Economic stability and security can lead to families choosing to have fewer children.
The Demographic Transition Model
Describes the shift in population growth patterns as a country industrializes.
- Stage 1 (Pre-industrial): High CBR, high death rates, slow population growth.
- Stage 2 (Early Industrial): High CBR, declining death rates, rapid population growth.
- Stage 3 (Late Industrial): Declining CBR, low death rates, slowing population growth.
- Stage 4 (Post-industrial): Low CBR, low death rates, stable or declining population.
Consequences of Later Childbirth
- Potential Increase in:
- Mental illnesses and birth defects in children.
- Difficulties conceiving and higher infertility rates in women.
Food Production and Population
- Agricultural Density: Number of farmers per unit of arable land.
- High agricultural density suggests lower efficiency in food production.
- Low agricultural density suggests higher efficiency and technology use (e.g., US).
- Technological Advancements: Improved agricultural technology increases efficiency, requiring fewer farmers and producing more food.
Public Health and Life Expectancy
- Industrialization and Urbanization: Initially led to poor sanitation and disease outbreaks (e.g., cholera, plague).
- Stage 2/3
- Public Sanitation Improvements: Sewer systems, water treatment, and hygiene practices drastically increased life expectancy.
- Stage 3