A new statistical estimate projects that the world population could reach nearly 11 billion by the end of the century, according to a United Nations report issued June 13 - about 8 percent more than their previous projection of 10.1 billion, issued in 2011.
Don't blame China, it's infant mortality and birth control in Africa that have defied the UN's last projection. The current African population is about 1.1 billion and the new estimates based on fertility forecasting now predict the population will reach 4.2 billion by 2100. Due to birth control and abortion, the UN had expected African birth rates to decline more than they have.
Global population reached 7 billion some time in 2011, according to estimates, after hitting 6 billion in 1999.
"The fertility decline in Africa has slowed down or stalled to a larger extent than we previously predicted, and as a result the African population will go up," said Adrian Raftery, a University of Washington professor of statistics and of sociology. The statistical methods developed by Raftery and his colleagues at the
University of Washington
Center for Statistics and the Social Sciences used updated data collected by the U.N. in order to project the long-term consequences of the fertility change in Africa. They say the new result uses finer-tuned statistics that anticipate the life expectancies of women and men across this century.
In other areas of the world, data is more accurate and trends are more predictable. Europe will undergo a decline because births continue to be below replacement level (though immigration will offset much of that) and other nations around the globe may see modest increases due to longer life expectancies.
Other projections are that population will stall well before 2100, based on societal trends where greater wealth and education lead to lower fertility. But population explosion worry hasn't been on the cultural radar since its craze status of the 1960s. Food is no longer a barrier now and more just a technological hurdle. Climate change and economics are bigger worries in the 21st century but population concerns should not go away, the sociologists argue.
"These new findings show that we need to renew policies, such as increasing access to family planning and expanding education for girls, to address rapid population growth in Africa," Raftery said.
The UN gives high and low variants of its projections, assuming that women have an average of half a child more or less than the best projection. That leaves a large uncertainty, from 7 billion to nearly 17 billion, in the range for potential world population by the end of this century.
By contrast, the UW research group has developed probabilities of future population levels to be coupled with best forecasts. "Our probability intervals are much tighter, ranging from 9 billion to 13 billion in 2100," Raftery said.