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…
Why would it be an issue, assuming we weren't fighting a way, for a country to shrink? There will of course be some economic hurdles to over come as constant and unsustainable growth is done away with, but after that what is the issue?