Nigeria's population is expected to surpass that of the United States by 2050, according to new United Nations projections.
The projections predict the West African country could be the world's third most populous by the end of this century.
The UN report on world population prospects: the 2012 revision, published last Thursday, predicts the world's population, now at 7.2-billion, will reach 8.1-billion in 2025. By the middle of the century, it is expected to top 9.5-billion and reach nearly 11-billion by 2100.
More than half the growth predicted between now and 2050 is expected in Africa, where the number of people is set to more than double, from 1.1-billion to 2.4-billion. Africa's population will continue to increase, even if there is a drop in births, says the report, which predicts the number of people living in Africa could reach 4.2-billion by 2100.
Several other countries, including India, Indonesia, Pakistan and the Philippines, are also set for significant population increases.
India, currently the world's second-largest country by population, is expected to rival China in size by 2028, when both nations will each have about 1.45-billion citizens. After 2030 China is expected to shrink in numbers, reaching an estimated 1.1-billion by the end of this century, when India's population is projected to reach about 1.5-billion.
Some of the most rapid increases are expected in the world's 49 least-developed countries. The populations of Mali, Niger, Somalia, Tanzania and Zambia are expected to increase at least fivefold by 2100.
In contrast, the populations of 43 countries are expected to decrease in the next few decades. Belarus, Bulgaria, Cuba, Romania, Russia, and Ukraine are among the countries where populations are expected to drop by more than 15% by 2050.
"These future trends are not guaranteed," stressed John Wilmoth, director of the population division of the UN's department of economic and social affairs. Wilmoth, who said the future shape of the world will depend largely on what happens to fertility rates, underlined the continued unmet need for family
planning in many countries.
Migration from developing to developed countries is projected to average roughly 2.4-million people each year from 2013-2050 before dropping to 1-million each year from 2050-2100. Without this, the populations of many European and other developed countries would be expected to decline significantly. – © Guardian News & Media 2013