I’d say there might be an ‘optimum’ somewhere in between - on average slightly lower rate than replacement, aiming for sustainable decline without crisis, preserving cultural heritage - as human cultural diversity matters as well as biodiversity. But we lack intelligent discussion of this topic - partly as it’s hard for people to imagine intuitively how small annual changes integrate over time.I’d like to further develop my interactive model - designed for climate projections but including a demographic model, to help people experiment for themselves, including regarding potential changes in global migration fluxes.

The pattern is well established. As societies grow wealthier and more secular, and woman gain greater agency, birthrates come down.

Well, urbanisation and our inability to plan cities for kids might, just might, have something to do with it. In the town I work 1/6 of families that live in urban neighbourhoods have kids, while it’s 4/10-5/10 in areas of bungalows with proper gardens.

Add an unstable political/medical/economical environment and housing policy becomes relevant. In good times it might be ok to have kids while living in a city flat and plan for moving to greener pastures as it becomes necessary, but not if you can’t count on having a job when it’s time to buy a new house. And with the housing market being what it is today for first time buyers…

No wonder nobody wants to have a baby!