By contrast, the fall in the growth rate since 1965 has been caused by voluntary reductions in fertility. Though fertility in the rich countries has been falling for more than a century, the news in 1965 was the reduction of child-bearing in the poor countries, where a majority of the world's people lived and live. Both the speed of population growth since World War II, and the dramatic fall in global fertility since 1965 are without precedent. The timing and magnitude of both events were not predicted by anyone. Let us think about population as one vertex of a symmetrical pyramid in which the other vertices are the environment, economics, and culture.
Any corner can go on top.
One reason no one foresaw the rapid rise in population and the fall in fertility after World War II is that our understanding did not, and still does not, encompass these four dimensions. Thinking in terms of this pyramid provides a checklist of crucial dimensions, though it will not eliminate uncertainty about the future. This article offers some speculations about the future. I offer these speculations to encourage us all to imagine a positive future we can work toward. Population and Society Let's begin with population and society.