The Demographic Transition

Lumen Learning

151 The Demographic Transition

Lumen Learning

Learning Outcomes

Describe the demographic transition theory of human population growth.

Demographic Transition Theory

Societies develop along a predictable continuum as they evolve from unindustrialized to postindustrial. Demographic transition theory (Caldwell and Caldwell 2006) suggests that population growth develops along a predictable four-stage model.

In Stage 1, birth, death, and infant mortality rates are all high, while life expectancy is short. An example of this stage is the 1800s in the United States. As countries begin to industrialize, they enter Stage 2, where birthrates are higher while infant mortality and the death rates drop. Life expectancy also increases. Afghanistan is currently in this stage. Stage 3 occurs once a society is thoroughly industrialized; birthrates decline, while life expectancy continues to increase. Death rates continue to decrease. Mexico’s population is at this stage. In the final phase, Stage 4, we see the postindustrial era of a society. Birth and death rates are low, people are healthier and live longer, and society enters a phase of population stability. Overall population may even decline. For example, Sweden is considered to be in Stage 4.

The demographic transition in five stages. The graph shows how stage 1 has high birth and death rates, then in stage two the death rate falls rapidly while birth rates rise, causing a natural increase. This continues into Stage 3, then in stage 4, there are low birth rates and low death rates, and in stage 5 birth rates begin to slowly increase again.

Figure 1. This shows how the changes in birth and death rates affect total population during the demographic transition stages.The United Nations Population Fund (2008) categorizes nations as high fertility, intermediate fertility, or low fertility. The United Nations (UN) anticipates the population growth will triple between 2011 and 2100 in high-fertility countries, which are currently concentrated in sub-Saharan Africa.

A graph projecting the growing population of Africa. It shows that in 1950, the population was around 200 million, and is expected to rise to over 4 billion by 2100. — **Figure 2. Projected Population in Africa:** This graph shows the population growth of countries located on the African continent, many of which have high fertility rates. (Graph courtesy of USAID)

For countries with intermediate fertility rates (the United States, India, and Mexico all fall into this category), growth is expected to be about 26 percent.

A bar graph predicting the growing population of the United States. It shows that in 1950, the population was at around 150 million, and is expected to rise to over 450 million by 2100. — **Figure 3. Projected Population in the United States:** The United States has an intermediate fertility rate, and therefore, a comparatively moderate projected population growth. (Graph courtesy of USAID)

And low-fertility countries like China, Australia, and most of Europe will actually see population declines of approximately 20 percent.

A graph predicting the growing population of Europe. It shows that in 1950, the population was at around 550 million, then rose to 740 million in 2013, and is expected to fall to around 600 million by 2100. — **Figure 4. Projected Population in Europe:** This chart shows the projected population growth of Europe for the remainder of this century. (Graph courtesy of USAID)

GLOSSARY

carrying capacity:: the amount of people that can live in a given area considering the amount of available resources

demographic transition theory:: a theory that describes four stages of population growth, following patterns that connect birth and death rates with stages of industrial development

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