I suspect there’s a good chance that populations in Western nations could be significantly higher than predicted according to your link. The reason for this is that we should expect natural selection to select for whatever traits maximize fertility in the modern environment, such as higher religiosity. This will likely lead to fertility rates rebounding in the next several generations. The sorts of people who aren’t reproducing in the modern environment are being weeded out of the gene pool, and we are likely undergoing selection pressure for “breeders” with a strong instinctive desire to have as many biological children as possible. Certain religious groups, like the Old Order Amish, Hutterites, and Haredim are also growing exponentially, and will likely be demographically dominant in the future.
I suspect there’s a good chance that populations in Western nations could be significantly higher than predicted according to your link. The reason for this is that we should expect natural selection to select for whatever traits maximize fertility in the modern environment, such as higher religiosity. This will likely lead to fertility rates rebounding in the next several generations. The sorts of people who aren’t reproducing in the modern environment are being weeded out of the gene pool, and we are likely undergoing selection pressure for “breeders” with a strong instinctive desire to have as many biological children as possible. Certain religious groups, like the Old Order Amish, Hutterites, and Haredim are also growing exponentially, and will likely be demographically dominant in the future.
I think this is a relevant consideration, but murkier than it appears at first glance.