El Niño (2025–26)
Shifts jet stream, allows Saharan heat plumes to penetrate deep into Europe; weakens Atlantic cooling effect
El Niño (2025–26): Rated high severity — the jet stream shift lets Saharan heat plumes travel deep into Europe while weakening the Atlantic's natural cooling influence.
Human-Caused Climate Change
Raises baseline temperatures; makes "once-in-a-century" events occur annually; elevates night-time minimums
Climate Change: Rated high severity — raised baseline temperatures mean events once expected once a century now recur annually.
Urban Heat Island Effect
Cities absorb and re-radiate heat; concrete and asphalt raise local temperatures by 2–5°C above rural surroundings
Urban Heat Island: Rated moderate severity — built surfaces in cities can push local temperatures 2–5°C above nearby rural areas.
Blocking High Pressure
Stationary anticyclones trap hot air for extended periods, preventing cooler air masses from entering
Blocking High Pressure: Rated high severity — stationary anticyclones can trap heat in place for extended periods with no relief.
Deforestation & Land Use
Loss of forest cover reduces evapotranspiration; dry soils absorb more heat and reflect less radiation
Deforestation & Land Use: Rated moderate severity — less forest cover means less natural cooling through evapotranspiration.