My concern is that population will shrink after 2100 globally but it will already be shrinking in the rich countries long before that. And all indicators right now is that shrinkage will speed up. There is something wrong with rich modern secular society here or anywhere (it happens to all societies right now whether they are European, Japanese, Chinese, etc) in that it currently leads to sub replacement reproduction…
In the past we thought that overpopulation is going to be a big global problem. It turned out that rich countries naturally ended up having fewer and fewer children. This stabilized their populations. And now we expect that this trend will continue.
But why? What's to say that some shift in society won't trigger another population growth in rich countries? Then what?