[DM] "Secular Stagnation Part 1 - Paul Krugman's Bicycling Problem"

[rfmcdonald]

Demography Matters co-blogger Edward Hugh has a post up there--and at A Fistful of Euros and his own blog, too--talking in-depth about the consequences of demographic change on economic growth. Put simply, if populations start aging or even start to shrink, where will economic growth come from?

The background to the argument (as originally, even if prematurely, explored by Alvin Hansen, Günar Myrdal and even John Maynard Keynes himself in the 1930s) is that the population dynamics set in motion by the industrial revolution of the late 18th century have reached a historic turning point. In the two centuries or so that have elapsed since what many term the modern growth era got going three related but distinct processes co-existed in time:

1/ positive trend population growth
2/ positive trend economic growth
3/ steadily accelerating technical change

You could call these the "stylized facts" which characterize the modern growth era, but the secular tendency in two of them is about to undergo a seismic shift. At some stage during the 21st century global population will peak, and then gradually start to decline, probably forever more. In fact in some countries (principally in Eastern Europe, but also Japan, Germany, Spain, Portugal, and Greece) population is already falling. All of Europe will likely head in this direction sometime in the 2020s, although there is considerable uncertainty still about the actual path dynamics of this process since in addition to birth rates immigration rates also play a part. At the present time some countries in Europe (the UK, Germany, Switzerland) are in receipt of large numbers of migrants annually, while others are losing working age population precisely to the aforementioned trio.

Hence the significance of the fact that Paul Krugman uses the expression "demographic transition" (for the first time to my knowledge) in the quote which opens this post. We are not talking here about some one-off problem (although often observers have spoken about Japan in just these terms), but a generalized phenomenon, a transition, something which eventually will affect all countries on the planet and our entire species. Previously people have tended to use the expression "demographic transition" to refer to the increase in the proportion of working age population and total population that accompanies the drop in fertility from high levels in less developed economies. The expression "demographic dividend" has often been used to describe the boost to economic activity this shift entails. Normally people assumed that this process would come to a halt around the 2.1tfr replacement level, but in one developed economy after another this hasn't happened, and those in which it has have been more the exception than the rule. So now reality pushes us towards a broadening in the definition of that transition towards acceptance of a later phase wherein populations age, and ultimately decline, a process which is greatly accelerated in those countries which have experienced long term very low fertility.

What Alvin Hansen and others started to think about in the 1930s was what the consequence would be for the second of the secular process which have characterized the modern growth era (positive economic growth). What happens if populations (or better put working age populations) start to shrink?

Hugh examines the issues at length.