Despite a continuing slowdown in the rate of population growth, it is “almost inevitable” that the number of people on the planet will rise from 7.3 billion today to 9.7 billion in 2050, according to the latest UN projections.
Ten years ago, the world population was growing by 1.24% annually; today, the percentage has dropped to 1.18% – or roughly another 83 million people a year. The overall growth rate, which peaked in the late 1960s, has been falling steadily since the 1970s.
The UN report attributes the slowdown to the near-global decline in fertility rates – measured as the average number of children born to a woman over her lifetime – even in Africa, where the rates remain the highest.
However, that fall is being offset by countries in which populations are already large, or where high numbers of children are born. According to the study, nine countries will account for half the world’s population growth between now and 2050: India, Nigeria, Pakistan, the Democratic Republic of Congo, Ethiopia, Tanzania, the US, Indonesia and Uganda.
“Continued population growth until 2050 is almost inevitable, even if the decline of fertility accelerates,” says the report, World Population Prospects: the 2015 revision.
“There is an 80% probability that the population of the world will be between 8.4 and 8.6 billion in 2030, between 9.4 and 10 billion in 2050 and between 10 and 12.5 billion in 2100.”
By 2050, six countries – China, India, Indonesia, Nigeria, Pakistan and the US – are expected to have populations of more than 300 million.
The report suggests that Africa alone will drive more than half of the world’s population growth over the next 35 years, during which time the population of 28 of the continent’s countries will more than double. It is predicted that by 2050, Nigeria’s population will surpass that of the US, making the west African nation the third most populous country in the world.
If current birthrate trends persist, Africa, which contains 27 of the world’s 48 least developed countries, will be the only major area still experiencing substantial population growth after 2050. Consequently, its share of the global population is forecast to rise to 25% in 2050 and 39% by 2100. Asia’s share, meanwhile, will fall to 54% in 2050 and 44% in 2100.
“Regardless of the uncertainty surrounding future trends in fertility in Africa, the large number of young people currently on the continent who will reach adulthood in the coming years and have children of their own, ensures that the region will play a central role in shaping the size and distribution of the world’s population over the coming decades,” says the report.
John Wilmoth, director of the population division in the UN’s department of economic and social affairs, said the new projections laid bare the scale of the task facing the world as it prepares to agree the development framework for the next 15 years.
“The concentration of population growth in the poorest countries presents its own set of challenges, making it more difficult to eradicate poverty and inequality, to combat hunger and malnutrition, and to expand educational enrolment and health systems, all of which are crucial to the success of the new sustainable development agenda,” he said.
Wilmoth explained that although population growth rate had declined “gradually but steadily” since the 1970s, it had done so at different speeds in different parts of the world.
“Africa is currently the region of the world where population growth is still rather rapid due to continued high levels of fertility, but even there we see the sorts of changes that were predicted and expected in the sense that, once populations start to have a higher level of life expectancy, they also come to realise that there’s not the same need to produce as many children,” he said.
“With increasing child survival, it just doesn’t make as much sense to have such large families as it did in the past.”
China, the world’s most populous country with 1.4 billion people, is expected to be overtaken by India (1.3 billion) within the next seven years. From 2030, when its population is projected to reach 1.5 billion, India is likely to experience several decades of growth. China, on the other hand, is set to experience a slight decrease after the 2030s.
Of all the world’s major regions, only Europe can expect a steady decline in its population over the remainder of this century, with its total inhabitants expected to shrink from 738 million people now to 646 million in 2100.
Almost half the people in the world (46%) live in countries with low levels of fertility, where women have fewer than 2.1 children on average during their lifetimes. Such countries include all of Europe and northern America, 20 Asian countries, 17 Latin American or Caribbean ones, three in Oceania and one in Africa.
Another 46% live in “intermediate fertility” countries – such as India, Indonesia, Pakistan, Bangladesh, Mexico and the Philippines – where women have on average between 2.1 and five children.
The remainder live in “high-fertility” countries, where fertility declines have been only limited and where the average woman has five or more children over her lifetime. All but two of the 21 “high-fertility” countries are in Africa; the largest are Nigeria, the Democratic Republic of the Congo, Tanzania, Uganda and Afghanistan.
The slowdown in population growth provoked by the overall fall in fertility will also cause the proportion of older people to increase over time: the number of older people in the world is projected to be 1.4 billion by 2030, 2.1 billion by 2050, and could rise to 3.2 billion by the turn of the next century.
In Europe, 34% of the population is predicted to be over 60 by 2050 (up from 24% today); in Latin America and the Caribbean, the proportion of people in the same age group will more than double to reach 25% by the middle of the century. The population of Africa, which has the youngest age distribution of any area, will age rapidly, with the proportion of people aged over 60 increasing from 5% today to 9% by 2050.
Although the report predicts that the global population will reach 8.5 billion in 2030, 9.7 billion in 2050 and 11.2 billion in 2100, the UN acknowledges that its predictions could be skewed by slower-than-projected declines in fertility.
It currently estimates that global fertility will fall from 2.5 children a woman in 2010-2015 to 2.4 in 2025-2030 and 2.0 in 2095-2100. Steep declines are also projected for the world’s least-developed countries, with the average dropping from 4.3 in 2010-2015 to 3.5 in 2025-2030, and 2.1 in 2095-2100.
However, should fertility rates not decline along the predicted lines – if, for example, all countries had a rate that was half a child above the medium variant – the global population in 2100 could swell to 16.6 billion people, more than five billion more than the current estimate.
“To realise the substantial reductions in fertility projected … it is essential to invest in reproductive health and family planning, particularly in the least-developed countries, so that women and couples can achieve their desired family size,” says the report.
“In 2015, the use of modern contraceptive methods in the least-developed countries was estimated at around 34% among women of reproductive age who were married or in union, and a further 22% of such women had an unmet need for family planning, meaning that they were not using any method of contraception despite a stated desire or intention to avoid or delay childbearing.”
The latest projections are based on the previous report, the 2010 round of national population censuses and recent demographic and health surveys.
