The fertility rate – the average number of children a woman gives birth to – is falling.
If the number falls below approximately 2.1, then the size of the population starts to fall.
In 1950, women were having an average of 4.7 children in their lifetime.
Researchers at the University of Washington’s Institute for Health Metrics and Evaluation showed the global fertility rate nearly halved to 2.4 in 2017 – and their study, published in the Lancet, projects it will fall below 1.7 by 2100… More here.
For decades we have worried about over-population and more recently about the increasing average age of our populations. Seems that just the latter will be a problem and that the opposite of the former could occur. I suspect many will not realise just how big a problem this could be.