The world will experience "peak youth" in 2020 for the first time in human history, as the number of people aged over 65 is expected to outnumber those under 5 years old.

As BofAML notes, a key implication of an aging population is that an economy's savings rate tends to rise while increases in investments tend to decline.

It is this aging global population that has thwarted the "war on deflation" in recent years (among other things like excess debt, deleveraging, and technical disruption)...

Aging populations increase the need to save for a longer retirement and lead to higher healthcare costs (note that in the next 10 days, 112,000 people will reach retirement age in the US, Europe, and Japan).

Source: BofAML