Demographers are projecting that population in some parts of the globe—Russia, the Ukraine, Japan, much of Western Europe—are set to decline over the next 50 years or so.  Of course, the talk of a shrinking population seems to send some people into a panic, which is why you occasionally see stories decrying the new "population crisis"—not too many people, but too few.

The Economist has this to say about the doomsayers:

People love to worry—maybe it’s a symptom of ageing populations—but the gloom surrounding population declines misses the main point. The new demographics that are causing populations to age and to shrink are something to celebrate. Humanity was once caught in the trap of high fertility and high mortality. Now it has escaped into the freedom of low fertility and low mortality. Women’s control over the number of children they have is an unqualified good—as is the average person’s enjoyment, in rich countries, of ten more years of life than they had in 1960. (Emphasis added.)

That seems just right to me.  And the article makes some other worthwhile points too—including that economic output per capita is a far better measure of the health of an economy than total output.  Measured by total output, a place with a shrinking population could seem to be in economic decline, even if the average person is getting wealthier.  (Of course, even better than total output per capita would be a measure that looks at how the poor and middle class are faring.  Still, policymakers should keep in mind that per capita measures of economic health are more significant than total output.)