With many of the world‘s poorer countries still seeing strong growth, the global fertility rate — the number of children born per couple — remains around 2.5, more than enough to replace every person currently alive.

But in richer countries, the rate has already nosedived. Russia, Singapore and several other developed countries have introduced policies to boost fertility but with mixed success.

Exact predictions vary, but most projections suggest the global population will peak at around 9 billion around 2070 and then start to fall, perhaps very fast.