Demographic Transition

To stereotype the poorest countries with the custom of large family sizes is to turn a blind eye to history. Most people now living in richer countries will discover similar fecundity in their own families by tracing back just a few generations.

The circumstances might have had much in common with contemporary African countries – poverty and high child mortality, dependence on surviving children for economic support, lack of education or job opportunities for women and the unavailability of any form of contraception.

7 Billion and Counting Why is the world population growing so fast if the annual growth rate has slowed? The demographic transition explained by Population Reference Bureau.

The evolution to lower fertility rates experienced in developed countries correlates with their improving social and economic circumstances. This demographic transition reflects how access to modern medicine combines with greater choice in work, education and lifestyle to lessen the appeal of large families.

In the transition from high to low fertility and mortality rates, the latter has invariably outpaced the former, as more children survive into adulthood and as adults live longer. The consequence is a rapid rise in national population. When the birth rate finally stabilises at its lower level, a country’s population profile will progressively age as the “baby boom” generation matures.

Countries around the world find themselves at very different points within the demographic transition. The apparent headlong rush towards a world population of over eleven billion therefore masks a complex mix of underlying trends.

The 47 Least Developed Countries are at an early stage of the transition, where child mortality and life expectancy indicators are improving but the average fertility rate of 4.3 children per woman remains high. Their aggregate populations are projected to reach 1.9 billion by 2050, almost 20% of the anticipated global population.

The contrast with richer countries is dramatic. The fertility rate in Europe fell so low that latest UN figures show that it has started to increase once again. In no fewer than 83 countries, including Brazil, Iran and Thailand, the fertility rate has fallen below 2.1, the threshold for natural population replacement. 46% of the world’s population is therefore stable or falling.

Global population and the changing shape of world demographics – statistics from The Economist show how older people will represent an increasing proportion of world population

Equally surprising is the UN’s warning that the assumption that fertility rates will continue to fall in some of the world’s poorest countries is very uncertain. The demographic transition in a hard core of about 20 high fertility countries is stalling, with rates remaining stubbornly high. Countries such as Nigeria and Democratic Republic of Congo seem to be  trapped in a demographic vortex of poverty and conflict.


more Population briefings (updated March 2018)
World Population Projections
Demographic Dividend
Population Policies
Opposition to Family Planning
Overpopulation or Overconsumption?
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