A useful tool to look at population densities across the world. It also shows the weighted density (density at which an average person within a country or metropolitan area lives).

luminocity3d.org/WorldPopDen/ Weighted density is often a better measure of judging density, as it focuses on personal experience instead of just showing a plain average across an area. When talking about personal behavior (like fertility rates), it is the experienced density per person that matters.

Distribution of births by birth order (whether it is a first, second, etc. birth) by countries in 2021 (or 2020 or 2019, depending on what the most recent figures are). There are some interesting patterns that plain TFR numbers aren't showing. The lowest average birth order is in South Korea, where third births are already rare and fourth or higher order births are pretty much nonexistent. The highest average birth order of the countries shown is in Israel, where fifth and higher order kids are pretty common.

Inspired by this, I checked into EU data of 2020 and compared the TFR and the % of births that were 4th and higher order. There are essentially four models (TFR, percentage):

Spain 1.19, 3.7%
Czechia 1.71 4.2%
Finland 1.38 10.0%
France 1.82 7.7%

https://twitter.com/DumbLayman/status/1623712548360011777

Put into words:
Spain has low fertility and few large families
Czechia has high fertility and few large families
Finland has low fertility and many large families
France has high fertility and many large families.
All other EU countries are inbetween.

Continuing the discourse on life expectancy, here are my pre-covid estimates for the life expectancy of the major metropolitan areas of some developed and semi-developed countries. Urban life expectancy is often higher than the country average, so it makes sense to focus on that. While Hong Kong, Madrid and Tokyo offer the highest life expectancy to their residents, the biggest "urban bonuses" are found in Moscow and the SF Bay Area.

Since the new World Population Prospects were now leaked a few days before the official release date (July 11), I will collect my observations in this thread. The post-2015 fertility collapse has now also partly been incorporated into the projections. World population is projected to reach 9.687B in 2050, to peak in 2086 at 10.43B and to reach 10.36B in 2100. 3 years earlier, it was like this: 2050: 9.736B, 2100: 10.87B and no peak.

Answers depend on what is really meant here: Why fertility is generally low in the developed world, or why fertility has suddenly declined further in many developed countries in the last 10 or so years.

https://twitter.com/Molson_Hart/status/1443014518729228298

The answers to the first question are already well known anyway, so here are some possible explanations for the recent decline (in no particular order, just as they came up in my mind).

Destatis released new figures on Covid birth trends in Germany from Jan-May 2021 - Births increased 1.4% to Jan-May 2020 (they compared final 2020 to prel. 2021 figures, so it's a different result compared to my birth table, where it's +3.9%). Share of extramarital births went down from 33% to 32%. There were no changes in the distribution by birth order (46% firstborns, 36% second-borns and 18% third-etc.-borns).