UNITED NATIONS — The United Nations forecast Thursday that the world's population will increase from 7.2 billion today to 8.1 billion in 2025, with most growth in developing countries and more than half in Africa. By 2050, it will reach 9.6 billion.
India's population is expected to surpass China's around 2028 when both countries will have populations of around 1.45 billion, according to the report on "World Population Prospects." While India's population is forecast to grow to around 1.6 billion and then slowly decline to 1.5 billion in 2100, China's is expected to start decreasing after 2030, possibly falling to 1.1 billion in 2100, it said.
The report found global fertility rates are falling rapidly, though not nearly fast enough to avoid a significant population jump over the next decades. In fact, the U.N. revised its population projection upward since its last report two years ago, mostly due to higher fertility projections in the countries with the most children per women. The previous projection had the global population reaching 9.3 billion people in 2050.
John Wilmoth, director of the Population Division in the U.N.'s Department of Economic and Social Affairs, said the projected population increase will pose challenges but is not necessarily cause for alarm. Rather, he said, the worry is for countries on opposite sides of two extremes: Countries, mostly poor ones, whose populations are growing too quickly, and wealthier ones where the populations is aging and decreasing.
"The world has had a great experience of dealing with rapid population growth," Wilmoth said at a news conference. "World population doubled between 1960 and 2000, roughly. World food supply more than doubled over that time period."
"The problem is more one of extremes," he added. "The main story is to avoid the extreme of either rapid growth due to high fertility or rapid population aging and potential decline due to very low fertility."
Among the fastest growing countries is Nigeria, whose population is expected to surpass the U.S. population before the middle of the century and could start to rival China as the second most populous country in the world by the end of the century, according to the report. By 2050, Nigeria's population is expected to reach more than 440 million people, compared to about 400 million for the U.S. The oil-rich African country's population is forecast to be nearly 914 million by 2100.
The report found that most countries with very high levels of fertility — more than 5 children per women — are on the U.N. list of least developed countries. Most are in Africa, but they also include Afghanistan and East Timor.