Humanity is approaching its peak.

Demographic contraction reaches university admissions with a long delay and propagates through enrollment stocks of different durations. We integrate lagged demographic indices, cohort transitions and budgeted robust optimization to plan ramp-constrained incremental educational activity. The formulation uses a lower enrollment envelope for an activity floor and an upper envelope for resource protection while jointly propagating intake uncertainty and retention stress. A public-data case distinguishes four-year direct entry and two-year transfer routes around a 20,073-undergraduate reference. Under stated assumptions, nominal enrollment in 2043 is 12,067 and the lower envelope at uncertainty budget two is 11,357; an 85% activity floor requires 5705 peak incremental full-time equivalents (FTEs). Under the same envelope, deterministic and delayed-start plans produce 1046 and 4474 cumulative FTE-years of shortfall. Because the least-cost plan attains its ramp and capacity limits, operational draws that tighten a binding limit require re-planning; planning with those limits derated by 20% keeps the unchanged schedule feasible in all 1000 draws at 36% higher cost. Convergence checks, structural scenarios and public-record reconstructions support verification, but grade-level predictive validation remains unavailable. The results are conditional planning trade-offs, not validated forecasts or guarantees of participation in new programs.

This paper studies the effects of population growth on welfare in an OLG model, in which lower population growth raises output per worker but also reduces the ratio of workers to retirees. Under fairly mild restrictions on the model’s parameters, there exists an optimal population-growth rate—one that maximizes steady-state welfare. This growth rate may well be negative: it may be optimal for the population to shrink over time. The introduction of a pay-as-you-go social security system reduces the optimal population-growth rate.

Many population projections used by international and government agencies assume that, in today's low-fertility societies, future fertility rates will stop declining and roughly stabilize. This paper assesses the evidence for an equilibrium point or rebound from low levels. We show that there is no robust evidence for a systematic fertility rebound, or for a stable equilibrium point at any fertility level conventionally assumed. Instead, where and when fertility has fallen low, it has tended to keep falling. This is true across a range of data sources, time periods, and fertility measures: United Nations data on period total fertility rates for all country-years from 1950 to 2023; Human Fertility Database data on completed fertility for cohorts born between 1935 and 1975 in 31 countries; and fertility rates in subnational geographies in Japan, India, and the United States. We reconcile these results with a prior literature that documented fertility reversals among some low-fertility countries in the early 2000s. Our findings provide an empirical basis for re-examining the equilibrium and rebound assumptions embedded in widely used population projections.