Falling Fertility Rates
Falling fertility rates mean nearly every country could have shrinking populations by the end of the century.
And 23 nations - including Spain and Japan - are expected to see their populations halve by 2100.
Countries will also age dramatically, with as many people turning 80 as there are being born.
— Fertility rate: ‘Jaw-dropping’ global crash in children being born, James Gallagher for BBC News