Tagged demography · show all articles
Population change is not a mood or a headline. It is three measurable processes — fertility and mortality decline, a projection method, and documented migration mechanics — that set the terms cities must work with.
Fertility keeps falling almost everywhere, aging keeps compounding, and climate mobility keeps concentrating in a handful of places — here is what would have to be true, and what would prove it wrong, by 2035.
Census counts, UN cohort-component models, and migration surveys answer different questions about population change—coverage, projection, and motive—and comparing them on their own terms beats picking a winner.
How population projections, migration surveys, and housing-demand forecasts are actually built — cohort-component arithmetic, stratified sampling, and the demographic inputs that turn counts of people into counts of dwellings.
Large cities did not become survivable because people wanted them to. They became survivable when someone could borrow against future water rates. The evidence is stronger than the folklore, and the attribution is still contested.