Paul Krugman: Why Economists Worry About Population Growth

When the economist Alvin Hansen first proposed the concept of secular stagnation, he emphasized the role of slower population growth in depressing investment demand. (His warnings were made moot by the postwar baby boom.)

Modern discussions have returned to that emphasis: Japan's shrinking working-age population appears to be an important source of the country's problems, and the slowing population growth in Europe and the United States are important indicators that we may be entering a similar regime.

But whenever I raise these points, I get questions from people who ask why I don't regard slowing population growth as a good thing.