George Friedman writes:  The real question is whether a declining population matters. Assume that there is a smooth downward curve of population, with it decreasing by 20 percent. If the downward curve in gross domestic product matched the downward curve in population, per capita GDP would be unchanged. By this simplest measure, the only way there would be a problem is if GDP fell more than population, or fell completely out of sync with the population, creating negative and positive bubbles. That would be destabilizing.

But there is no reason to think that GDP would fall along with population. The capital base of society, its productive plant as broadly understood, will not dissolve as population declines. Moreover, assume that population fell but GDP fell less – or even grew. Per capita GDP would rise and, by that measure, the population would be more prosperous than before.

One of the key variables mitigating the problem of decreasing population would be continuing advances in technology to increase productivity. We can call this automation or robotics, but growths in individual working productivity have been occurring in all productive environments from the beginning of industrialization, and the rate of growth has been intensifying. Given the smooth and predictable decline in population, there is no reason to believe, at the very least, that GDP would not fall less than population. In other words, with a declining population in advanced industrial societies, even leaving immigration out as a factor, per capita GDP would be expected to grow.