European Heat Wave (2003)
A two-week heat wave killed roughly 15,000 people in France, most of them elderly city-dwellers in homes without air conditioning. The toll exposed how cities with low air-conditioning adoption are vulnerable to extreme heat.
France's health system was overwhelmed and a public inquiry followed.
The event pushed Paris and other European cities to build heat-warning systems and cooling plans for vulnerable households.
Like Paris in 2003, San Francisco has historically low air-conditioning penetration. Warm nights with little relief are the same mechanism that made the 2003 death toll so high.
