The global fear of too few young people

A new concern is taking hold across the developed world: rapidly aging populations that scare policymakers.

Why it matters: Population growth is key to maintaining demand for housing, filling jobs yet to be automated, and paying into pension systems pressed by demographic realities and slowing economic growth.

• "You basically have a very large portion of mankind that is aging and then the workforce is shrinking. But I would say the G20 in particular are aging faster," said Organization for Economic Co-operation and Development secretary-general Angel Gurria. (AFP)

The big picture: Some countries — like the U.S. — are feeling these issues less thanks to immigration. Others — like China and Japan — are more restrictive and feeling the bite in projected growth.

• As societies get richer and women get more rights, they work more and have increased access to contraceptives.
• While Europe and East Asia are already projected to lose population by 2050, the Western Hemisphere will mostly add people, and Africa's population is projected to soar, per UN projections.
• The developing world is predicted to bear the brunt of climate change impacts, including potential political instability, meaning many more people might want to move to developed countries.
• As we've seen in Europe and the U.S. in recent years, that isn't going well.

The bottom line: Earth has plenty of workers to do the jobs we need, just not in the countries where the jobs are right now. Fixing that mismatch is shaping up to be a central political challenge for the upcoming decades.

Go deeper: Special report... The aging, childless future