Global population is projected to peak at 9.7 billion in 2064 and decline to 8.8 billion by the end of the century, according to a study from the University of Washington Institute for Health Metrics and Evaluation. The reversal of population growth — already in progress in some countries — is due primarily to women’s better access to education and contraception.

By 2100, 183 of 195 countries will not have fertility rates necessary to maintain their current populations, with 23 countries shrinking by more than 50%. By contrast, the population of sub-Saharan Africa is projected to triple, and almost half the world’s population will live in Africa and the Middle East.