The global population is predicted by the United Nations to reach 9.7 billion by 2050, with the largest growth figures to be in the world's poorest countries.
The world's population is getting older and growing at a slower pace but is still expected to increase from 7.7 billion now to 9.7 billion in 2050, according to the United Nations
The UN Department of Economic and Social Affairs' Population Division said in a new report that world population could reach a peak of nearly 11 billion around the end of the century.
But Population Division Director John Wilmoth cautioned that because 2100 is many decades away this outcome "is not certain, and in the end the peak could come earlier or later, at a lower or higher level of total population."
The new population projections indicate that nine countries will be responsible for more than half the growth between now and 2050. In descending order of the expected increase, they are: India, Nigeria, Pakistan, Congo, Ethiopia, Tanzania, Indonesia, Egypt and the United States.
In sub-Saharan Africa, population is projected to nearly double by 2050, the report said.
Undersecretary-General for Economic and Social Affairs Lu Zhenmin said in a statement: "Many of the fastest growing populations are in the poorest countries, where population growth brings additional challenges in the effort to eradicate poverty," promote gender equality and improve health care and education.
The report confirmed that the world's population is growing older due to increasing life expectancy and falling fertility levels.
The global fertility rate fell from 3.2 births per woman in 1990 to 2.5 births in 2019 and is projected to decline further to 2.2 births by 2050.
In 2019, the fertility rate in sub-Saharan Africa was the highest at 4.6 births per woman, with Pacific islands, northern Africa, and western, central and southern Asia above the replacement level, said the report.
But since 2010, it said 27 countries or areas have lost one per cent or more of their population.
"Between 2019 and 2050 populations are projected to decrease by one per cent or more in 55 countries or areas, of which 26 may see a reduction of at least 10 per cent," the UN said. "In China, for example, the population is projected to decrease by 31.4 million, or around 2.2 per cent, between 2019 and 2050."
According to the "World Population Prospects 2019: Highlights" report, migration is also a major component of population growth or loss in some countries.
Between 2010 and 2020, it said 14 countries or areas will see a net inflow of more than one million migrants while 10 countries will experience a similar loss.