Demographic Transition

updated October 2016

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 many countries of contemporary Africa – 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.

The evolution to improved child health, lower fertility rates and longer life expectancy experienced in developed countries correlates with their improving 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. 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 ten billion therefore masks a complex mix of underlying trends

The 48 Least Developed Countries (LDCs) 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. Only 34% of women of reproductive age have access to modern methods of contraception. More than half of the population of these LDCs is aged under 25 and their aggregate populations are projected to double to 1.9 billion by 2050.

The contrast with richer countries is dramatic. In no fewer than 83 of these 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. The rate in some European countries has fallen so low that the UN’s World Population Prospects 2015 makes the assumption the fertility rates will increase in future years.

Equally surprising is the UN’s warning that the assumption that fertility rates will continue to fall some of the world’s poorest countries is very uncertain. The demographic transition in a hard core of 21 “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 aggravated by climate change.


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.

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

more Population briefings
World Population Projections
Demographic Dividend
Population and Development
Opposition to Family Planning
Overpopulation or Overconsumption?
Source material and useful links

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