The Population Division of the UN Department of Economic and Social Affairs (UN DESA) recently published its latest population projections for the 21st century. Its central projection is for the world’s population to increase from 8.2bn next year to a peak of 10.3bn in 2084 in 2084 before falling slightly to 10.2bn at the end of the century.

This means that the population will have increased by 2.0bn between 2000 and 2025 and is projected to increase by 1.5bn over the next 25 years to 9.7bn in 2050 and by 0.6bn to 10.3bn in 2075, before gradually starting to fall from 2084 onwards.

Our chart illustrates how this change differs by region, with the population of Africa expected to grow throughout the century from 1.5bn in 2025 to 3.8bn in 2100. South and Central Asia, which has seen its population grow from 1.7bn in 2000 to an anticipated 2.3bn next year, is expected to see further growth to 2.9bn in 2075 before then falling to 2.8bn in 2100, while the population of the Asia-Pacific region is expected to increase from 2.1bn in 2000 to 2.4bn in 2025, is expected to fall gradually from 2030 onwards to 1.5bn in 2100.

The population of the Americas is expected to grow slightly from 1.1bn in 2025 (up from 0.8bn in 2000) to 1.2bn before falling back to 1.1bn by 2100, while Europe and Middle East’s population is expected to increase from 0.9bn in 2025 (up from 0.8bn in 2000) to close to 1.0bn in 2050 and for the rest of the century.

UN DESA says the main driver of global population increase over the next 60 years until it peaks is the momentum created by growth in the past, with increases in the number of women of reproductive age until the late 2050s offsetting a declining fertility rate – currently one child fewer on average than in the 1990s (2.25 live births per woman currently compared with 3.31 in 1990). They also project that the number of people aged 65 will reach 2.2bn in 2080, surpassing the number of children under 18 in that year.

The declining fertility rate is one reason that the UN are projecting that the world’s population in 2100 will be 700m or 6% smaller than they were anticipating a decade ago, despite life expectancy starting to increase again after falling during the COVID-19 pandemic.

For some countries and areas, the declines in population are expected to be quite significant over the remainder of the century, such as the populations of China and Japan, which are expected to reduce from 1,416m to 633m and from 123m to 77m between 2025 and 2100 respectively. Meanwhile India is expected to grow from a population of 1,464m in 2025 to a peak of 1,701m in 2061 before falling to 1,505m in 2100.

Many other countries and areas have already or will shortly see their populations start to decline, except for about 52 countries and areas up until 2054, and 62 up until 2100, where immigration will be the main driver of population growth. The latter includes the UK, where the population is expected to rise from 70m in 2025 to a peak of 76m in 2073 before falling to 74m in 2100, and the US, expected to grow from 347m in 2025 to 421m in 2100.

According to the analysis by the UN, there are around 100 countries and areas (out of the 237 included in their analysis) with relatively youthful populations over the next half century that have a window of opportunity to accelerate their economic development. This ‘demographic dividend’ occurs when the share of the population of working ages is increasing faster than the overall population and a substantial and sustained decline in fertility increases the numbers available to work, assuming the countries concerned can put in the investment needed to take advantage of this opportunity.