Paris Is Literally Rehearsing the End of Summer

Picture this: it’s October 2023, and seventy children are descending into an abandoned Paris railway tunnel to pretend the world above is unbearably hot. Not a field trip—a disaster drill. Welcome to“Paris at 50 degrees Celsius,”one of the most ambitious urban heat simulations ever staged, and a window into how seriously some cities are now taking the climate crisis they can see barreling toward them.

The setup sounds almost surreal. As Pénélope Komitès, Paris’deputy mayor in charge of resilience, coordinated the exercise over eighteen months of planning, volunteers role-played heat stroke victims, power outages, carbon monoxide poisoning, and overwhelmed hospitals. Firefighters, city officials, and Red Cross workers scrambled through scenarios designed to test what happens when temperatures hit 122 degrees Fahrenheit—a threshold scientists warn is increasingly plausible by 2100. The current Paris heat record sits at 108.68 degrees Fahrenheit, set in July 2019. The gap between that and the imagined future is the space where a city either prepares or panics.

What makes this different from typical emergency response drills is ambition married to realism. More than 100 organizations participated, from utilities to nonprofits, and the whole operation cost €200,000. The simulation wasn’t designed to run smoothly—success actually meant exposing cracks. As Cassie Sunderland, managing director of climate solutions at C40, a global network of mayors focused on climate action, puts it:“Imagine if you suddenly have a huge amount of people who need additional health care, but doctors and nurses can’t get to the hospital because of transport failures.”That’s the kind of cascading failure a simulation can reveal before it becomes real.

The truly jarring finding? Parisians themselves were unprepared. The exercise revealed that public awareness was nearly nonexistent—people didn’t recognize heat stroke symptoms, didn’t know where cooling centers were, couldn’t imagine the scenario as anything but theoretical. That realization led to something possibly more important than infrastructure upgrades: in March, Paris opened its first Campus of Resilience, a public training center offering workshops and simulations open to all residents. Because, as Komitès says,“We need to talk with Parisians. To inform them, to prepare them.”

Barcelona is now adapting the Paris model. Taiwan is scaling up beyond cities, planning a live simulation for July. Even Phoenix, which created an entire heat department after an earlier exercise exposed coordination failures, shows how a well-run drill can shift municipal priorities. The message is clear: cities aren’t just planning for extreme heat anymore—they’re practicing it, learning in real time what breaks, who gets left behind, and what citizens need to know to survive.

The question isn’t whether these exercises help. It’s whether they’re enough, and whether cities can move fast enough to both rehearse the future and actually change it.