> A possible link would be that more progressive countries have more immigrants from places with higher fertility rates, and these immigrants are the ones pushing the TFR up.
Seems to me that this factor, when you can bring yourself to ignore the controversy of implied adjacent ideas, is one that can't be ignored if we want to understand the dynamics of culture, economics and fertility. To say that a liberal culture has a higher fertility rate is to ignore that liberal cultures often import populations from very conservative cultures. It's possible that the cultural differences between the European populations are negligible that if immigrant fertility were taken into account the line of best fit in these graphs would be flat. Or they could be inverse, or similar, we just don't know. But to ignore the possible effect is to not seriously strive to understand this dynamic.
I was disappointed that the author hadn't done a literature review, even a basic one. Perhaps they're an expert and didn't see the need, but they didn't cite anything or provide any further reading.
And it's not like this subject isn't researched.
There's so much [1] [2] that a literature review might be a really good place to start.
I would be really surprised if it's just one core issue to point at, there's a ludicrously long list of perfectly reasonable factors that all do their part. These graphs barely show any correlation at all, much less any causation.
In H. sapiens this has less to do with speciation and more to do with economic drivers. That is, we adapt to societal circumstance more than other species do. Examining populations in the 18th century, you needed to have a higher number of children, because half of them were likely to not make it to adulthood.
In modern Western society, this is no longer true, but that's a new wrinkle that has arrived in the last fifty years. That family behaviors didn't change to a noticeable degree until roughly twenty years ago, tells you there's something more going on than "the species is just like that."
As well as reducing population, negative birth rates have the side effect of ageing the population.
A population where most people are over 65 is one where ever more resources get spent on healthcare & pensions, paid for by the ever fewer number of working age people.
There’s also various toxic political effects ageing electorates can have on democracy.
There is a very rational argument for the population being expanded: we need the population pressure to push us to invest in launch cost reduction, space mining and colonization so it becomes feasible to move heavy industry and eventually the population into space to leave earth to recover. I would rather see earth become a pristine zoo than a tomb and reducing population only cuts a small subset of the risks of becoming a tomb and exacerbates others.
