The world's population has been rapidly growing and shows no signs of slowing down. New research suggests that by 2100, about 11 billion people could populate earth.
Published in the journal Science, researchers used more modern statistical tools to estimate the figure, which was previously predicted to reach only 9 billion.
"The consensus over the past 20 years or so was that world population, which is currently around seven billion, would go up to nine billion and level off or probably decline," says Dr. Adrian Raftery, the study's co-author and a professor of statistics and sociology at the University of Washington. "We found there's a 70 percent probability the world population will not stabilize this century. Population, which had sort of fallen off the world's agenda, remains a very important issue."
Africa is expected to grow from its one billion people today to approximately four billion at the end of the century, making it the place of the most anticipated growth. There is an 80 percent change that Africa's population will include 3.5 to 5.1 billion people by 2011.
Researchers contribute large family sizes and the lack of accessibility and education regarding contraception to the quadrupled statistic.
Asia, on the other hand, is expected to reach five billion people in 2015, up from 4.4 billion currently, before declining. Populations elsewhere are not expected to see significant population growth. North American, Europe and Latin America are all predicted to have a population that stays below one billion each.
The predictions support the 2013 population data released in July by the United Nations, while adding a new dimension. "This work provides a more statistically driven assessment that allows us to quantify the predictions, and offer a confidence interval that could be useful in planning," says Patrick Gerland, the study's lead author and demographer at the UN.
The population predictions are made based off of life expectancy, fertility rates, and rates of migration, whereas earlier techniques relied on expert opinion based on population trends and how they would change. "We can answer questions about future population growth using standard principles of statistical inference, which has never really been done before," Raftery says.
These statistics prove that population growth should become a top concern, seeing as population growth can exacerbate all types of problems, according to Raftery. Increased populations could pose threats to food supplies, natural resources, unemployment, crime and healthcare.
