Human Populations and Urban Systems - SL

Human Population Dynamics

Calculating Population Size

• Demographic tools include:

  • Crude Birth Rate (CBR)

  • Crude Death Rate (CDR)

  • Total Fertility Rate (TFR)

  • Doubling Time (DT)

  • Natural Increase Rate (NIR)

Population Inputs and Outputs

• Inputs: Births and immigration.

  • Crude birth rate: Number of live births per 1,000 people per year.

  • Immigration rate: Number of immigrants per 1,000 population per year.

• Outputs: Deaths and emigration.

  • Crude death rate: Number of deaths per 1,000 people per year.

  • Emigration rate: Number of emigrants per 1,000 population per year.

Total Fertility Rate (TFR)

• Average number of births per woman of childbearing age.

• TFR > 2.0: Population increase.

• TFR < 2.0: Population decrease.

• Replacement fertility ranges from 2.03 in MEDCs to 2.16 in LEDCs (due to infant mortality).

Life Expectancy

• Average number of years a person is expected to live from birth, assuming demographic factors remain constant.

Natural Increase Rate (NIR)

• NIR = Birth Rate - Death Rate

• Expressed per 1,000 or as a percentage.

Doubling Time (DT)

• Time it takes for a population to double at its current growth rate (NIR).

• DT = 70 / NIR

Human Population Prediction

• UN projection models:

  • High Fertility Scenario: Fertility remains higher than the median.

  • Probabilistic Median: Most likely scenario, considers current trends.

  • Low Fertility Scenario: Fertility declines faster than expected.

Factors Influencing Family Size

• High infant and childhood mortality.

• Security in old age.

• Children as an economic asset.

• Status of women.

• Unavailability of contraception.

National and Development Policies

• Population policies (anti-natalist or pro-natalist) manage growth rates.

• Address birth rates, immigration, and emigration.

Direct Influence on Population Growth

• Financial incentives for more children.

• Extended parental leave.

• Tax breaks for families.

• Sex education in schools.

• Access to contraception.

Anti-Natalist Case Study – China

• One-child policy (1979-2015).

• Advocates a three child policy now.

Pro-Natalist Case Study – Singapore

• Shifted from anti-natalist to pro-natalist in the 1980s.

• Offered incentives for families to have three or more children.

Indirect Influence on Population Growth

• Investment in education, especially for girls.

• Gender equality in the workforce.

• Improved public health care.

• Urbanization.

• Increased awareness of family planning.

Immigration and Population Growth

• Policies encourage immigration to fill labor gaps.

• Migrant workers seek employment, better pay, healthcare, and education.

Immigration Benefits

• Destination country gains workforce and tax revenue.

• Country of origin benefits from remittances.

Immigration Policies

• European countries encourage immigration.

• Asian countries restrict immigration.

Age-Sex Pyramids

• Model population composition showing the proportion of each gender in age groups.

Demographic Transition Model (DTM)

• Describes changes in birth and death rates through stages of development.

• Stage 1: High stationary (high birth and death rates).

• Stage 2: Early expanding (death rate drops, birth rate remains high).

• Stage 3: Late expanding (birth rates fall, population levels off).

• Stage 4: Low stationary (low birth and death rates).

• Stage 5: Declining (population decline).

Limitations of the DTM

• Based on industrialized countries.

• Doesn't account for all factors affecting birth and death rates.

• Doesn't consider rapid industrialization in some economies.