In 2017, the UN Population Division released a revision of its "World Population Prospects," a regularly-issued report that analyzes world population changes and other world demographics, estimated out to 2100. The recent report revision noted that the world population increase has slowed a bit, and is expected to continue to slow, with an estimated 83 million people added to the world every year.

Population Overall Grows

The United Nations forecasts the global population to reach 9.8 billion in the year 2050, and growth is expected to continue until then, even assuming that the decline in fertility would increase. An aging population overall causes fertility to decline, as well as women in more developed countries not having the replacement rate of 2.1 children per woman. If the fertility rate of a country is lower than the replacement rate, population declines there. The world fertility rate was 2.5 as of 2015 but declining slowly. By 2050, the number of people over age 60 will more than double, as compared with 2017, and the number over 80 will triple. Life expectancy worldwide is projected to rise from 71 in 2017 to 77 by 2050.

Overall Continent and Country Changes by 2050

More than half of the forecast growth in world population will come in Africa, with an estimated rise in population of 2.2 billion. Asia is next. Asia is expected to add more than 750 million people between 2017 and 2050. Next are the Latin America and Caribbean region, then North America. Europe is the only region anticipated to have a lower population in 2050 as compared with 2017.

India is expected to pass China in population in 2024, China's population is projected to stay stable and then to slowly fall, while India's is rising. Nigeria's population is growing the most quickly and is forecast to take over the United States' number three position in world population around 2050.

Fifty-one countries are projected to see a decline in population by 2050, and ten are estimated to drop by at least 15 percent, though many of them are not largely populated. The percentage per person is higher than in a country with a large population, such as Bulgaria, Croatia, Latvia, Lithuania, Poland, Moldova, Romania, Serbia, Ukraine, and the U.S. Virgin Islands (territory counted independently from the United States' population).

The least-developed countries grow more quickly than those with mature economies, but also send more people as immigrants to the more developed nations.

What Goes Into the List

Following is a list of the 20 most populous countries in the year 2050, presuming there are no significant boundary changes. Variables that go into the projections include trends in fertility and its rate of decline over the next decades, infant/child survival rates, numbers of adolescent mothers, AIDS/HIV, migration, and life expectancy.

Largest Populations by Country in 2050

India: 1,659,000,000 China: 1,364,000,000 Nigeria: 411,000,000 United States: 390,000,000 Indonesia: 322,000,000 Pakistan: 307,000,000 Brazil: 233,000,000 Bangladesh: 202,000,000 Democratic Republic of the Congo: 197,000,000 Ethiopia: 191,000,000 Mexico: 164,000,000 Egypt: 153,000,000 Philippines: 151,000,000 Tanzania: 138,000,000 Russia: 133,000,000 Vietnam: 115,000,000 Japan: 109,000,000 Uganda: 106,000,000 Turkey: 96,000,000 Kenya: 95,000,000

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