UNITED NATIONS, June 13 (Xinhua) -- The number of people in the world is hurtling to the 9.6 billion mark by 2050 from the present estimate of 7.2 billion, with most of the increase coming in developing countries, the United Nations projected on Thursday.
India will eclipse China as the most populated nation around 2028, while Nigeria could outrank the United States by 2050, UN Department of Economic and Social Affairs (DESA) said during the launch of "World Population Prospects: The 2012 Review," its most recent revision of the official UN population estimates and projections.
Developing regions are projected to increase from 5.9 billion in 2013 to 8.2 billion in 2050, said John Wilmoth, director of DESA's Population Division. The population of developed regions will remain largely unchanged at around 1.3 billion people.
The most rapid growth is expected in the 49 least developed countries, the report said. They are expected to double in population from around 900 million people in 2013 to 1.8 billion in 2050.
In 2028, both China, now at 1.38 billion people, and India, at 1.25 billion, are expected to match populations at 1.45 billion each, the report said. India's will continue to grow for several decades to around 1.6 billion and then begin to decline while China's population is expected to start decreasing after 2030, and by 2100 "possibly reaching 1.1 billion."
The United States ranks third behind China and India with 320 million people, followed by Indonesia at 250 million and Brazil at 200 Million. Nigeria ranks seventh at 174 million, just behind sixth ranking Pakistan at 182 million. By 2050, the report said, Nigeria will rank third at 440 million, compared to the United States estimated 401 million people.
Fertility, mortality and migration rates will affect future population trend trajectories, especially fertility, Wilmoth said in a statement accompanying the 50-page report. "For the world as a whole, fertility has fallen rapidly in recent decades, especially since the 1960s," he said. "Several large developing countries, including China, India, Indonesia, Iran, Brazil, South Africa and many others have experienced a rapid fall in the average number of children per woman," he said. "This has led to a reduction in population growth rates in much of the developing world."
"At the same time, many countries of Europe, East Asia and elsewhere, now have very low levels of fertility, well below their 'replacement level' of around 2.1 children per woman," Wilmoth said.
Most of the countries with relatively high levels of fertility are on the UN's list of 49 least developed countries, with many in sub-Sahara Africa.