Projecting compound environmental risk across the 21st century. An interactive atlas tracking how heat, air, and water stresses converge across 150+ cities in 120+ nations — defaulting to 2050 under IPCC SSP2-4.5. The middle 50% framing reveals where moderate risks compound into strategic vulnerability.
Environmental risk analysis typically fixates on extremes — the hottest cities, the most polluted air, the worst floods. But the most strategically important zone is the middle 50%: regions where heat, air, and water stresses are individually moderate but compound into consequential risk. These are the places where small shifts in any dimension can tip systems past critical thresholds — and where policy intervention yields the highest marginal return.
Temperature extremes combined with humidity create cascading health, energy, and infrastructure risks. Even moderate heat amplifies when paired with poor air or water scarcity.
PM2.5, ozone, and nitrogen dioxide create synergistic health burdens. Even below WHO alert thresholds, chronic exposure interacts with heat stress to amplify cardiovascular and respiratory risk.
Both drought and flooding stress are captured — precipitation deficits threaten agriculture and water supply, while excess moisture combined with poor drainage creates compound flood risk.
Data projected under IPCC SSP2-4.5 (middle-of-the-road scenario). City-level scoring across heat, air, and water — combined into a Compound Risk Index. Nations are color-coded by aggregate risk. Default view shows the middle 50% interquartile band. Toggle to see full distribution. Use the timeline to explore 2025–2100.
| City | Country | Region | Heat ▼ | Air ▼ | Water ▼ | Compound ▼ | Level |
|---|---|---|---|---|---|---|---|
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Each city receives a 0–100 score on three dimensions. The Compound Risk Index is a weighted combination: (Heat × 0.35) + (Air × 0.35) + (Water × 0.30). Scores are computed from real-time sensor and forecast data via Open-Meteo.
Interquartile ranges (Q1–Q3) are computed on the compound score distribution. The default view filters to the middle 50% band — excluding extreme outliers and negligible-risk cities to focus on the strategically significant middle.
Country-level risk is the average Compound Risk Index of all monitored cities within a nation. The choropleth map colors every nation with available data — unmonitored countries appear in neutral gray.
The compound risk lens surfaces patterns invisible to single-dimension analysis.
South and Southeast Asian cities consistently appear in the middle-upper band — not extreme on any single dimension, but persistently elevated across all three. Delhi, Dhaka, Kolkata, and Karachi each carry moderate heat, air, and water scores that compound into significant total burden.
Western European cities score low on air quality but show rising heat scores during summer months. The divergence creates a seasonal compound risk spike — air quality infrastructure is robust, but heat adaptation lags behind warming trends.
Water scores show the highest variance across the dataset. Cities within 500km can swing from drought risk to flood risk depending on local topography and monsoon patterns, making compound risk highly localized even within regions.
Over half of monitored cities fall within the interquartile compound risk band. These are the places where incremental policy changes — cleaner air standards, heat action plans, water infrastructure — can shift a city from moderate to low risk with the highest marginal return on investment.