Human Exposure · Polycrisis Systems Monitor
Compound exposure to air pollution, extreme heat and flood risk is the defining metric of 21st-century climate risk. This dashboard projects exposed populations under three scenarios from 2000 to 2100 — and shows where hazards overlap, not just where they strike.
| Region | Share exposed | % of population | People exposed |
|---|
Exposure to any one hazard is only part of the story. The population facing two or more simultaneous hazards is the metric that captures cascading health, water and infrastructure stress — and it grows faster than any single-hazard curve in high-pollution futures.
In the rapid decarbonisation scenario, PM₂.₅ exposure falls from ~4.3 billion people today toward ~0.9 billion by 2100 because the same transition that ends coal also removes the largest source of ambient particulate matter.
Compound exposure concentrates where high population density, biomass burning, and flood-prone deltas coincide. The regional table shows the burden is least mobile and least insured precisely where adaptive capacity is thinnest.
Projections are produced by the H Heuristics Polycrisis Exposure Model v1.0, a reduced-form cohort model anchored to published 2000–2020 benchmarks and extrapolated along three shared socio-economic pathway (SSP) narratives. Hazard thresholds: annual mean PM₂.₅ above 35 µg/m³ (WHO Interim Target-1); 30 or more days per year with dangerous heat (wet-bulb or 40°C+ equivalent); and residence in the 100-year coastal or riverine flood zone. Compound exposure counts people facing two or more of the three hazards simultaneously.
Status: experimental. Scenario curves are illustrative model estimates, not observational data; they are designed for systems reasoning, scenario comparison and magnitude intuition rather than point forecasting.