The Depopulation Bomb - WSJ

As global fertility rates drop, two economists make the case for humans - Greg Ip
If humanity’s existence were threatened by plague, nuclear war or environmental catastrophe, people would surely demand action.
But what if the threat came from our own, passive acceptance of decline? 

This is not some theoretical curiosity: It is a reasonable extrapolation of globally declining fertility rates.
People aren’t demanding action. 

In fact, some think a smaller population is actually a good thing...

• If global fertility fell to the current U.S. fertility rate of 1.6, world population will rise from 8 billion now to a peak of 10.2 billion in 2080 and then start to decline. 
• “It will not fall to 6 billion or 4 billion or 2 billion and hold there,” they write. 
• “Humanity could hasten its own extinction if birth rates stay too low for a long time.”...