Demographic Transition (College Board AP® Environmental Science): Revision Note

Demographic transition model

What is the demographic transition?

• The demographic transition is the shift from high birth and death rates to lower birth and death rates as a country develops economically

  • This transition is illustrated through the demographic transition model (DTM)

  • This model originally consisted of four stages and was based on the development of the UK

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Stages of the demographic transition model

Stage 1: Pre-industrial society (high stationary)

• High birth rates due to lack of contraception and high infant mortality

• High death rates due to disease, poor medical care, and food shortages

• Population growth is slow because birth and death rates are both high

• Example: No modern countries are in this stage, but some remote tribal societies may exhibit these characteristics

Stage 2: Early industrialization (early expanding)

• Death rates decline due to improvements in medicine, sanitation, and food supply

• Birth rates remain high, leading to rapid population growth

• Agricultural advancements increase food availability

• Example: Many developing countries, such as Niger, are in this stage

Stage 3: Mature industrialization (late expanding)

• Death rates remain low

• Birth rates begin to decline due to increased access to contraception, urbanization, and improved women’s education, leading to slowing population growth

• Economic changes shift societal focus from agricultural-to-industrial-based economies

• Example: Countries like Mexico and India are in this stage

Stage 4: Post-industrial society (low stationary)

• Both birth and death rates are low, leading to population stabilization

• Higher living standards and economic stability contribute to low fertility rates

• Aging populations may emerge due to lower birth rates

• Example: The United States and most European nations are in this stage

Characteristics of developing countries

Key characteristics of developing countries

Higher infant mortality rates

• Limited access to healthcare, nutrition, and sanitation leads to increased infant deaths

• Example: Countries with weak healthcare systems, such as Chad, experience high infant mortality

More children in the workforce

• Economic necessity, where families rely on children's labor for survival due to financial hardship, forces many children to work instead of attending school

• Example: In some developing nations, children work in agriculture or informal labor markets

Lower literacy rates

• Limited access to education, particularly for women, affects literacy levels

• Example: Countries like Afghanistan have lower literacy rates due to barriers to education

Agriculture-based economies

• Many developing nations rely on subsistence farming rather than industrial production

• Example: A large percentage of the population in Ethiopia is engaged in agriculture

Limited infrastructure

• Many developing countries lack clean water, reliable electricity, and modern sanitation

• Example: Rural areas in countries like Haiti struggle with inadequate infrastructure

Characteristics of developed countries

Key characteristics of developed/industrialized countries

Lower birth and death rates

• Both birth rates and death rates fall to low, stable levels as a country industrialises (Stage 4 of the demographic transition model)

• Example: most Western European countries, Japan, and the United States have crude birth rates of around 8–12 per 1,000 and crude death rates of around 8–10 per 1,000

Lower total fertility rate (TFR)

• The total fertility rate (average number of children per woman) often falls below the replacement level of ~2.1, driven by widespread access to contraception, women's participation in higher education and the workforce, and later age of first marriage

• Example: South Korea, Italy, and Japan have TFRs below 1.5, leading to long-term population decline without immigration

Higher life expectancy and lower infant mortality rates

• Advanced healthcare, vaccination programmes, clean water, and reliable nutrition reduce deaths across all age groups

• Example: Japan and Singapore have life expectancies above 84 years and infant mortality rates below 3 per 1,000 live births

Aging populations

• A combination of low birth rates and long life expectancy produces a larger proportion of elderly people, placing pressure on healthcare systems, pensions, and the working-age tax base

• Example: in Japan and Germany, more than 20% of the population is aged 65 or over

Higher literacy rates

• Universal compulsory education, including for girls and women, produces near-universal literacy and longer average schooling, which itself reinforces lower fertility rates

• Example: most developed countries report adult literacy rates above 99%

Service-based and industrial economies

• Most workers are employed in services (finance, healthcare, education, IT) and manufacturing, rather than subsistence agriculture

• Example: in Germany, the United States, and the UK, the service sector makes up over 70% of GDP

Robust infrastructure

• Reliable electricity, clean piped water, modern sanitation and sewage treatment, and well-developed transport networks support high living standards in both urban and rural areas

• Example: countries such as the Netherlands and South Korea have near-universal access to clean water and electricity