Population Dynamics & LDA+ (2025–2125) — Alvin J Lin

Population Dynamics & LDA+ Consumer Base (2025–2125)

Explore how fertility, ageing, migration & policy shape long-horizon legal drinking age (LDA+) populations across major centres.

Year
2025
Scenario
Global fertility drag1.00×

Meaning: Drag > 1.0× = births decline faster ⇒ smaller cohorts ageing into LDA after ~18–21 years. Drag < 1.0× = slower decline.

Migration offset (pp)0.00%

Meaning: Adds ±percentage points to annual growth (e.g., +0.20%). Inflows boost the LDA+ base immediately across adult ages; outflows reduce it.

Regions

Trend: Selected Regions

Lines show total population or LDA+ base (toggle). Tip: falling total with flat/rising LDA+ ⇒ rapid ageing; rising total with slower LDA+ ⇒ youthful base yet to reach LDA.

Ranking at 2025

World Map

Darker = larger market size for the selected metric in the chosen year. The fill updates smoothly as the year animates.

Assumptions, Drivers & Sources (expand)

Purpose. Directional scenario tool to illustrate how fertility-driven dynamics can reduce the LDA+ consumer base. Not a demographic projection engine.

Drivers. Fertility (birth pipeline), age structure (cohorts ageing into LDA), migration (net inflow/outflow of adults), mortality (older ages), policy (LDA 18/20/21).

Curve. g(t) = g0 · exp(−k · (t − 2025)) + migration_offset, with drag scaling k. Negative growth ⇒ shrinkage.

LDA+ share. Baseline share shifts with ageing; bounded 50–95%.

Sources. UN DESA World Population Prospects; World Bank Open Data; WHO/OECD/IARD/national statutes for LDA.

© 2025 Alvin J Lin — MIT License (full text retained in previous version).