Fertility rate: 'Jaw-dropping' global crash in children being born

The world is ill-prepared for the global crash in children being born which is set to have a "jaw-dropping" impact on societies, say researchers.

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.