CAMBRIDGE, Mass., July 28 (UPI) -- World population will hit 7 billion this year and then add 2.3 billion more -- as many people as lived on the planet in 1950 -- by 2050, U.S. researchers say.
David Bloom, a professor of economics and demography at Harvard University, said the increase will bring unprecedented global demographic upheaval.
By 2050 nearly all of the 2.3 billion projected increase will be in the less developed regions, with nearly half in Africa, he said in an article in the journal Science.
By contrast, the populations of more developed countries will stay flat but will be aging, with fewer working-age adults to support retirees living on social pensions, he said.
"Although the issues immediately confronting developing countries are different from those facing the rich countries, in a globalized world demographic challenges anywhere are demographic challenges everywhere," Bloom said.
The world's population has grown slowly for most of human history, only reaching 1 billion in 1850.
However, in the past half-century, population has jumped from 3 billion to 7 billion, a Harvard release said.
"The demographic picture is indeed complex, and poses some formidable challenges," Bloom said. "It's just plain irresponsible to sit by idly while humankind experiences full force the perils of demographic change."