The number of people on earth is likely to reach 11 billion by 2100, about 2 billion higher than widely cited previous estimates, reveals a study led by University of Washington and United Nations published in Science journal on Thursday. Published ahead of the United Nations general assembly meeting in New York, the study reveals using new statistical tools that there is an 80% probability that the world’s population, which stands at 7.2 billion today, will increase to between 9.6 and 12.3 billion in 2100, led by a steep rise in Africa.
Africa is expected to see the greatest rate of growth. Experts estimate with 95 percent confidence that Africa’s population will rise from one billion to between 3.1 and 5.7 billion by 2100, bringing the population density in Africa to the level of China today. The findings were published today in the journal Science. Experts attribute three-quarters of the increase in population growth to people having more children that live longer. Other areas of the globe, such as Asia and Latin America, have been experiencing birth rate drops since 1950, researchers said. Asia is expected to peak at 5 billion people in 2050, and North America, Europe, and Latin America and the Caribbean are expected to remain below 1 billion people each.
“The consensus over the past 20 years or so was that world population, which is currently around 7 billion, would go up to 9 billion and level off or probably decline,” said corresponding author Adrian Raftery, a professor of statistics and of sociology at University of Washington. “We found there’s a 70% 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.” According to the paper, this is the first UN population report to use modern statistics, known as Bayesian statistics, that combine all available information to produce better predictions.
“Rising population could exacerbate world problems such as climate change, infectious disease and poverty,” said Raftery. “Studies show that the two things that decrease fertility rates are more access to contraceptives and education of girls and women, Africa could benefit greatly by acting now to lower its fertility rate”, he added. The study is the first to use modern probabilistic methods. It was led by researchers from the United Nations Population Division and several other universities.
The report concludes that the growing global population will require new environmental, economic, health, governmental, and social policies.