According to the latest United Nations projections, more than half of future population growth will live in sub-Saharan Africa – which will create a young continent but could also exacerbate poverty and inequality in the region.
Population is a dynamic area. In recent years, birth rates and population trajectories have changed significantly across countries and continents. However, the global population continues to grow by more than 80 million a year, and if no action is taken, the population will continue to grow for the rest of the century. Rapid population growth, and its causes, will pose a major obstacle to achieving the Sustainable Development Goals, particularly in the areas of eradicating hunger and poverty, achieving gender equality, and improving health and education.
How we got to this point
Current world population: 7,951,913,200 (this number is growing every second, as of 9 a.m. on July 9)
■ Population growth since 1050 / United Nations
Until the time of Napoleon, the population at any point in time on Earth was less than 1 billion. Since World War II, the world's population has increased by 1 billion every 12 to 15 years. The world's population today is more than double that of 1970.
Where we're going
■ UN Population Projections, up to 2100 (95% of the defined range) / 2019 UN data
■ green: + half a child; Blue: Median forecast; Huang: - Half a child / 2019 UN data
Every two years, the United Nations makes projections of future population growth. According to the latest projections, with moderate growth (and most likely), the world's population will reach 9.7 billion by 2050 and 10.9 billion in 2100. Because many factors affect population growth, the United Nations gives a range of projections based on different assumptions. Within a 95 percent definitive range, the gap between the highest and lowest values of the 2100 population projections is nearly 4 billion — more than half of our population today.
The second graph above shows how the population would change under all three conditions, assuming that one of the average two households had one or more children less than the median projection.
This suggests that small changes in household size can lead to large disparities in the total population. If a modest reduction in births could be achieved, more than 3 billion fewer people would be lost by 2100 – and the world's total population would be lower than it is today.
Where population growth will occur
■ UN data on population growth projections for all continents 2020-2100/2019
■ UN data for the most populous countries 2020-2100/2019
By 2050, nine countries will account for more than half of the projected population growth: India, Nigeria, Pakistan, the Democratic Republic of the Congo, Ethiopia, Tanzania, Indonesia, Egypt and the United States.
India is expected to overtake China as the world's most populous country by around 2027.
• It is projected that 55 countries will experience population declines by 2050.
(Data provided by the United Nations Population Fund in 2019)
Rapid population growth and its causes will pose a major obstacle to achieving the Sustainable Development Goals, particularly in the areas of eradicating hunger and poverty, achieving gender equality and improving health and education. Poverty is also an important driver and predictor of population growth. The total population of the "least developed countries" designated by the United Nations is expected to grow from just over 1 billion in 2020 to 1.76 billion in 2050.
For the remainder of this century, more than half of the world's population growth will live in sub-Saharan Africa. While the overall world fertility rate (i.e. the average number of children per woman) is declining, fertility rates remain high in most African countries (see "Reducing fertility rates" below). Because of high fertility rates, the population of sub-Saharan Africa is very young: 60 per cent of the population is under the age of 25. This means that many people are entering childbearing age. At the same time, life expectancy is increasing and child mortality is falling thanks to improved access to health care, which means that more "generations in the same house" families are now emerging.
Projections of the populations of different continents and countries have taken into account the situation of future migration, but this factor is very contingencies. In addition, climate change, poverty and the pressures on the population itself will also lead to high global population movements, with Africa likely to be the largest source of migration.
The impact of inequality
Looking at these numbers, it's important to remember that while the Global South has the highest population growth rates and much of the North has lower population growth rates, consumption, resource use, and carbon emissions are much higher in the world's richest regions. This means that each individual in a rich country has a much higher impact on the global environment than in poor countries – rich countries also have a greater impact on household size and overall population.
■ Per capita carbon dioxide emissions from consumption in 2017
Fertility rate and population
■ Fertility rates in the most populous countries
The "Total Fertility Rate" (TFR), which refers to the amount of fertility per woman's lifetime, indicates changes in family size. When the TFR reaches 2.1, it is called the "replacement rate", and the country's population will eventually stabilize.
The latest UN estimate of global TFR is just under 2.5 (although the most recent estimate is 2.3)
Sub-Saharan Africa has the highest TFR: 4.6
Nearly half of the world's population now lives in countries with a TFR below 2.1.
Fertility rates are expected to decline globally, and by 2050 no country will have more fertility than 5 children per woman.
The population is also affected by mortality, net migration and the proportion of the population of childbearing age. Populations in countries with fertility rates below replacement levels tend to continue to experience natural growth (births minus deaths) over a period of time. Especially in places where recent birth rates are high, when babies born during this period enter childbearing age, they increase the number of families, even if their family size is smaller than the previous generation. This is called "demographic momentum," meaning that the effects of fertility changes often take decades to be reflected in the population.
The impact of immigration
Since net migration is positive, the populations of many countries with low replacement rates are also growing. When immigrants import more than they export, they directly increase the population and also increase the birth rate. This is usually because immigrants are more of working-age young people and are therefore more likely to have children than the average of the existing population, and in some cases, they are more likely to come from countries or cultures that focus on fertility and family size.
In countries with negative net migration, their populations are decreasing, or growing at a slower rate than they should. If the person leaving is of childbearing age (which is usually the case), this can lead to a further decline in fertility in the country. In some cases, fertility rates are already low in such countries (e.g. Bulgaria and Romania).
Reduced fertility
■ Fertility rate 1960-2015
■ Effective national family planning policy
Currently, more than 200 million women in developing countries have unmet needs for voluntary family planning, which means that although they do not want to become pregnant, they do not use contraceptive methods. Research published by the Gutmacher Institute suggests that this is usually because they don't have access to contraceptives, but more often because of misinformation or fear of side effects. Nearly a quarter of the cases are due to the objections of their male partners or people close to them to their use of contraceptives. The provision of contraception must be accompanied by education, support and women's emancipation to be effective.
Another important factor in contraception is the ideal family size. Religious, cultural and social, as well as economic and political factors, all play a role in this. Where the state cannot be fed, people tend to pursue large families to ensure that someone provides them with an old age. Where child mortality rates remain high, there is also a desire to have more children. In these places, the "value" of women and girls may be internalized through the evaluation of the number of children born, and the tradition of valuing the extended family is often internalized.
This article is compiled from the article "Population: the numbers" on the website of the British non-profit organization PopulatIng Matters.