The Lancet study was conducted by the University of Washington’s Institute for Health Metrics and Evaluation (IHME). It found that global TFR was barely above replacement level in 2021 and will fall to 1.83 as soon as 2050. By then, some countries’ populations will have halved as a result.
The causes of the fertility crunch are many and complex, but some major elements stand out. One is development. As a society becomes more advanced, women can more easily access education and so have more opportunities in life besides child-rearing. Meanwhile, more accessible contraception and better healthcare means more children survive infancy, so people may choose to have fewer of them.
Development also brings urbanisation. According to the UN, more than half the world now lives in towns and cities, where accommodation might support only small families or none at all. This is a world away from the old agrarian need for lots of children to help work the land.
Other factors include economic pressures, fears over future wars and climate change, and sociocultural factors such as attitudes to family, religion and tradition.