World sees population boom

World's population will hit 7 billion in 2011, which is double what it was in the 1960s, a study said.
David Bloom, a professor of economics and demography at Harvard University, said the increase will bring unprecedented global demographic upheaval putting strains on space, labour and the environment.
And, if estimates turn out to be true, things are going to get far, far worse: By the year 2100, the earth could be home to a staggering 15.8 billion people.
By 2050 nearly all of the 2.3 billion projected increase will be in the less developed regions, with nearly half in Africa.
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, the study added.
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.