A study published in The Lancet
last week found that fertility fell dramatically in many countries over the past 70 years but that the global population is still rising. On average, women in 1950 were having 4.7 children in their lifetime on average and by 2017, that had had halved to 2.4 children per woman. During the same period, the global population nearly tripled from 2.6 billion to 7.7 billion. 91 of the countries in The Lancet's study are experiencing a "baby bust" and that means their birth rates have fallen below the levels needed to sustain their population size.
The total fertility rate at which a population replaces itself between generations without migration is known as "replacement" and the rate stands at 2.05 live births. Nearly half the world's countries are below that threshold
, meaning their populations will decline if nothing changes. Most of the countries losing fertility are developed and reasons for the trend include declining childhood mortality, greater access to contraception and more women being educated and heading to work.
The story is different in the developing world where higher rates of fertility
are fueling global population growth. Illustrating the gulf in global fertility, the West African country of Niger has a fertility rate of 7.1 while Japan and Singapore have a rate of just 1.3. The following infographic shows the top-10 countries with the highest rates of fertility worldwide in comparison with a selection of developed nations that have seen their rates plunge since the middle of the 20th century.