How might depopulation reverse itself?

That is the topic of my latest Bloomberg column, drawing upon an earlier discussion by Robin Hanson.  The problem is this: if families find that having three or four kids just isn’t that fun, and women wish to focus more on their careers, which forces might be capable of reversing that trend?:

One possibility is that a shrinking population itself will bring self-reversing mechanisms. For instance, a Japanese population half its current size would make Japan an emptier place, presumably lowering land prices. Some families would find it easier to afford a larger apartment in central Tokyo and perhaps decide to have more children.

But that mechanism seems more likely to reduce population decline than to reverse it. Living space is only one of many factors behind decisions about family size. And as population declines, the stock of houses and apartments will decline too, so in the longer run the amount of space per family may not increase by very much…

Another factor in declining fertility, especially in the U.S., is single parenthood. If a potential mother is facing a fertility decision without another full-time parent on the scene, she is more likely to choose to have fewer children. As population falls, will single-parent families become less common? It is hard to see why. Whether the issue is a lack of marriageable men, unstable family norms or women who simply prefer to go it alone, there is no particular reason to think those factors will disappear in an era of population decline.

And:

What might be some other intervening factors to restore fertility? Perhaps tender and loving robots will make it much easier to raise young children. Or maybe, as populations fall to much lower levels, a sense of moral panic will set in. Families might decide to have more children, feeling that the very survival of their country is at stake. A more elaborate and dystopian scenario would be that corporations take over empty parts of the globe and pay for the raising of children there, in return for a share of their future income.

Here is Ross Douthat’s Sunday column on broadly similar issues, each column was written independently of the other.  As I interpret his discussion, he is more (potentially?) optimistic about ideological and religious forces reversing the decline than I am, in any case an interesting contrast of approach.  By the way, here is Robin Hanson’s proposal for how to escape the problem, more economistic than either Ross or myself.