THE global population may peak at around 9.7 billion in 2064 before falling to 8.8 billion by the end of the century, a new study suggests.
Researchers at the University of Washington have based their forecast on a falling overall fertility rate, which is the average number of children a woman gives birth to, as girls get better access to education and contraception.
The projected fertility rate indicates that by 2100, 183 of 195 countries will not be able to maintain current populations, with forecasts indicating 2.1 births per woman.
Some 23 countries will see populations plummet by more than 50 per cent, according to the researchers. But the population of sub-Saharan Africa could triple, due to a declining death rate and more women entering reproductive age.
Scientists from the Institute for Health Metrics and Evaluation (IHME) at the university's School of Medicine used data from the Global Burden of Disease Study 2017.
The modelling study, published in The Lancet, also predicts a shift in global economic power brought on by "dramatic declines in working-age populations in countries such as India and China".
The population of Japan is predicted to shrink from around 128 million in 2017 to 60 million in 2100, that of Spain from 46 to 23 million.
Professor Stein Emil Vollset, first author of the paper, said: "While population decline is potentially good news for reducing carbon emissions and stress on food systems, with more old people and fewer young people, economic challenges will arise as societies struggle to grow with fewer workers and taxpayers, and countries' abilities to generate the wealth needed to fund social support and health care for the elderly are reduced."
