The Correlation between Economics and Population Growth: The Demographic Transition Theory

As the earth teeters on the edge of 6.5 billion inhabitants and counting, fertility rates are plummeting world wide. How is this possible, if we are still growing at an alarming rate? McNeil et al. (2000) claims the world has experienced at least two doublings of the world’s populations since 1500. Academia has used the demographic transition theory to explain the population explosion of the last century, and attribute economic growth as the cause.
The demographic transition theory separates population growth and reduction into four stages. Keyfits (1992) explains that in n the first stage a nation’s birth rates and death rates are both extremely high, keeping population growth low. The high birth rate is attributed to little family planning and the economic need for large families attributed to a primarily agricultural economy. Families need more hands in the fields. Death rates are high because of lack of adequate health care. As a nation begins to become more complex and possibly influenced by the global economy, they move into stage two. In stage two, western medicine reduces the death rate while the birth rate remains high due to the persistence of the agricultural economy. Less people are dying while still more are born. As the country industrializes, they move into stage three, where death rates continue to decline and birth rates plummet. As a society urbanizes, large families become costly. Where it used to be adaptive to have large families to cultivate farms, now urban structures make large families cumbersome, expensive, and maladaptive. As a country becomes fully industrialized, contraceptives and family planning become more available and the birth rate remains low and stable, as does the death rate.

In this transition, the nation experiences an explosion in population due to the low death rate and continued high birth rates. Although most of the developed world (ex. Sweden) has already completed the transition, many nations are still stuck in the second and third stages of the demographic transition (ex. Mexico). Some nations (ex. African nations) are still in the first stages and will be preparing to start their transition shortly (). There are some controversies over whether economic development is the cause of the population growth due to ambiguous data. However, Keyfitz asserts that the initial trigger of the decrease in death rate is most definitely due to the beginning of the country’s increased economic development (1992). Regardless, we can expect the world’s population to continue to explode for at least another century.

Keyfitz, N. “Completing the Worldwide Demographic Transition: The Relevance of Past Experience.” Ambio, 21. 1, (1992): 26-30. 10 Nov. 2009

Pluijim, B. v.d. "Population Growth over Human History Lecture" Image: "The Demographic Transition" 2000. U. Michigan.

McNeil, J. R. An Environmental History of the Twentieth-Century World: Something New Under the Sun. W.W. Norton&Company, Colorado, 1-17.