Record Temperatures: Paris braces for future of paralysing heat

Imagine Paris at 122 degrees Fahrenheit, or 50 Celsius.

The asphalt streets would melt in spots, making it virtually impossible for ambulances and buses to pass. The lights and fans could cut out in neighbourhoods if underground cables burned or junction boxes shifted. Cellphone service might go down as antennas on boiling rooftops stopped working. Trains would halt as outdoor rails swelled, keeping nurses, firefighters, and electricity engineers from reaching their jobs when they were most needed.

Those are situations city officials are already planning for.

“A heat wave at 50 degrees is not a scenario of science fiction,” said Pénélope Komitès, a deputy mayor who oversaw a crisis simulation two years ago based on those presumptions. “It’s a possibility we need to prepare for.”

France has recently experienced its second heat wave of the summer, with temperatures reaching record highs last week in the southwest and heat alerts covering three-quarters of the country. In Paris, this has become the new normal. Eight of the 10 hottest summers recorded in the city since 1900 occurred since 2015.

In 2019, temperatures in Paris hit a record, nearing 109 degrees. Scientists say it will get worse, particularly since climate change is warming Europe at more than twice the global average.

In 2022, city officials asked climate scientists if Paris might experience heat waves that reach 50 degrees Celsius soon.

Their answer was yes, possibly, by the end of the century, or as soon as around 2050 if greenhouse gas emissions increase exponentially. But the scientists’ modelling showed that scenario was unlikely if global pledges from the Paris climate accord were met and the rise in warming was kept below 2 degrees Celsius.

“I don’t think we should bet on that as a society,” said Alexandre Florentin, a green city councillor and environmental engineer who spent more than a decade working at Carbone 4, a leading French climate change mitigation and adaptation firm.

He led a committee of city lawmakers, from all political parties, to examine the capital’s vulnerabilities to extreme heat waves. They published their report, Paris at 50°C, in 2023, separately from the crisis simulation.

They found that there were temperature thresholds that could cause widespread breakdowns, leading to a cascade of crippling domino effects.

During an interview with a hospital director, for example, Florentin learned that the medical centre’s air-conditioning system was designed to work only when the outside temperature was about 109 degrees or lower.

Any higher and it would break down, and the hospital would be forced to close its operating rooms and send urgent cases to other hospitals. “What would happen if they have the same problem?” Florentin said. “He didn’t have an answer.”

Another important finding was the vulnerability of schools, should a heat wave hit during the school year — like in late June. “The classes will close, and that will have rippling consequences all through society,” Florentin said. “If their parents work at a hospital or the electricity facility, there will be bigger problems” — meaning understaffing at crucial times.

His strongest recommendation was for the city to invest more in green and shaded yards and to transform schools into “passive” cooling centres with designs that allow for more air circulation or geothermal cooling systems, not electricity.

Just under 15,000 people died from heat-related causes in 2003 during a heat wave that hit France that August. Many were older adults living in apartments that had zinc roofs with no insulation or air conditioning, according to reports by national lawmakers and the national public health agency.

In May, Prime Minister François Bayrou passed a decree requiring all workplaces to create an extreme heat plan.

The city government has doubled down on its own adaptation plans — pulling up asphalt parking places and the centre of roads to plant trees — 15,000 last winter alone, said Dan Lert, deputy mayor in charge of the city’s ecological transition and its climate plan. “Our first line of defence is massively plant,” Lert said in an interview. “The best natural air conditioners in Paris are trees.”

Another key part of the defence plan is insulating the city’s buildings, so they can better resist heat waves. But the challenge is daunting. There are 1 million private apartments in Paris, few with insulation, he said.

“It’s a race against time,” Florentin said. “There is going to be a lot of change. The question is what percentage of change we want and prepare for, and what percentage we just suffer through.”

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