That declining birthrate, coupled with a rapid industrialization that has pushed people from rural towns to big cities, has created what can feel like a two-tiered society. While major metropolises like Seoul continue to grow, putting intense pressure on infrastructure and housing, in regional towns it is easy to find schools shut and abandoned, their playgrounds overgrown with weeds, because there are not enough children.
More people in more countries may soon be searching for their own metaphors. Birth projections often shift based on how governments and families respond, but according to projections by an international team of scientists published last year in The Lancet, 183 countries and territories — out of 195 — will have fertility rates below replacement level by 2100.
Many demographers argue that the current moment may look to future historians like a period of transition or gestation, when humans either did or did not figure out how to make the world more hospitable — enough for people to build the families that they want.