In its annual survey of the world's population, the Washington-based Population Reference Bureau reports a sharp contrast between industrialized nations watching their populations decline and developing nations that are adding millions of people. The lopsided growth rates will affect regional economies.
The world's population is expected to reach nine billion by the year 2050, nearly 50 percent more than the current total of 6.3 billion. Most of the growth will occur in Africa, Asia and Latin America.
While the number of births is increasing in the developing world, the number of births in the developed world is decreasing and its population is aging. That puts a greater burden on fewer people to support the needs of a developed society.
The U.S. population is one of the few that is on the increase, which demographers attribute in part to expanding immigrant communities that favor large families.
Demographer Carl Haub of the Population Reference Bureau does not expect the trends to change. "We know two things about future population growth," he said. "One is that the developed countries are not going to grow as a group. The second thing we know is the developing countries are going to grow. What we don't know is how much."
The Population Reference Bureau's survey estimates that developing countries add about 80 million people a year while developed countries only contribute about one million.
India, for one, is expected to grow by more than 50 percent in the next half-century, to more than 1.5 billion people. U.N. population statistics show that one week of India's growth equals the weekly growth of all 22 member states of the European Union combined.
The continent of Africa is projected to equal three times the EU population by mid-century.
Mr. Haub told a news conference that population growth reflects the effectiveness of family planning programs, economic, health and other conditions. Still, he says the AIDS virus, which has devastated several African nations, has not curbed overall population growth rates.
"When AIDS first began to be noticed in a big way - in the late '80s and early '90s - people naturally assumed that AIDS would cause the African population to decrease," he said. "And that is just not going to happen. AIDS has certainly hurt individual countries - Kenya, South Africa and, above all, Botswana. However, for the continent as a whole, Africa will be adding about a billion people over the next 50 years."
Economists underline the challenges for the world's poorest nations that already are straining to feed and care for an ever-growing youthful population. The Population Reference Bureau's report shows that one in three persons in the developing world is under the age of 15.