A new forecast says the world’s population will peak at 9.7bn in 2064

THE WORLD’S population may never grow as large as many had previously assumed. In a new paper, researchers at the Institute of Health Metrics and Evaluation at the University of Washington project that the global population will top out in 2064 and then fall steadily. Current estimates by the UN’s Population Division reckon it will continue to grow until at least 2100. As a result, the IHME estimates a total population of 8.9bn in 2100; the UN places the number at about 10.9bn.

The huge discrepancy is largely accounted for by differing views on two issues. First, the IHME study’s central scenario assumes that improvements in access to education and contraceptives in sub-Saharan Africa—and a concomitant fall in fertility—will result in a population there of just under 3.1bn in 2100, compared with 3.8bn in the UN study. Accounting for mortality, this means 890m fewer African births on a cumulative basis in the remainder of the century. However, even the IHME’s conservative projections still have sub-Saharan Africa as the only continent with a growing population by the end of the century.