As climate change drives temperature increases across Europe, heatwaves are becoming more frequent and more intense. While the mercury has not yet hit 50C in France, a group of researchers is giving people the chance to experience life at that temperature, touring the country with a heated container in tow.
"I feel as though I need to take deeper breaths, even though I’m not making much of an effort," says Martin Estivals, after a few minutes of walking on a treadmill in the Climate Sense heat chamber.
The chamber is a container on a lorry that has been travelling around France for the past few months. Inside it looks like a doctor’s office, with treadmills at one end. The ambient temperature is a steady 50C.
The highest temperature recorded to date in France is 45.9C – in the southern village of Gallargues-le-Montueux, during a heatwave in 2019. Europe's highest temperature was recorded in Sicily in 2021 – 48.8C.
Estivals, 26, and his friend Emma Louise Robeyns, 21, wanted to try out the chamber when it was in Marseille in the spring, after hearing about it from a friend.
A report on the climate chamber, in the Spotlight on France podcast
Cognitive effects
The pair spend 30 minutes inside, walking on a treadmill, attempting a few fine motor tasks and completing cognitive tests.
On the treadmills, they are asked to walk normally, as if they were going to work or out shopping. After 10 minutes, Robeyns says her head feels hot.
She and Estivals move on to the next task: moving loops around, to avoid them touching each other – manual tasks that are made harder by their sweating.
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Ten minutes later, they are having real trouble with the cognitive tasks. "I can’t even read the first line of the instructions," Robeyns says, incredulously.
She tries to recall words or find differences between images – simple tasks that would be no problem in normal temperatures, but after 20 minutes in 50C she feels her brain slowing down.
"They all look alike," she says, looking at two images in which she is asked to find the differences. "Usually I’m pretty good at this kind of exercise. But I must admit that this is difficult. I think my body is focused on the basics, and it’s forgetting about the rest."
Impact on the body
Robeyns is more than ready to leave as soon as the 30 minutes are up. On the way out, she and Estivals test their body temperatures and heart rates, to compare them with the readings from the way in. Robeyns' temperature has risen by 2C.
Christian Clot of the Human Adaptation Institute, which runs the climate chamber, says high heat has real physiological impacts.
As the body struggles to stay within its normal range of approximately 36–37C, organs work harder and the brain slows down to save energy.
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"You lose certain cognitive capacities – of concentration, decision-making and calculation,” he explains, adding that social skills are impacted too. "Being social takes a lot of energy, and the heat makes you become more irritable or you just want to spend less time with others. And bit by bit, your social skills break down."
'An abstract concept'
He believes that putting people through this kind of heat stress is key to raising awareness of climate change and how human behaviour affects it, saying that global warming is an abstract concept until the physical repercussions feel real.
"For a person to change their behaviour, they must be affected sensorially and emotionally. To understand the climate of the future, you need to have an experience that allows you to feel it emotionally. It helps people make decisions on how they act today."
The institute's follow-up surveys have shown that more than 60 percent of visitors to the climate chamber say they will change their behaviours, to be more conscious of CO2 emissions.
For Robeyns, who is originally from Paris but now lives in Aix-en-Provence, where temperatures are regularly extremely high in summer, the experience in the chamber has driven home the impact of global warming on daily life.
"No matter how aware you are, it’s good to be confronted with the real repercussions of our daily actions," she said.
Estivals is not sure whether he will change anything in particular, but the experience has made him realise what an increase of just a few degrees feels like.
"It’s hard to imagine 50C, and this allows us to test it," he said. "What is more difficult is to imagine that it could be like this all day. It is not the same as just a few moments."
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Speed is key
Clot says that if the world fails to keep carbon emissions down, France could see 50C by the middle of the century – a scenario he hopes can still be avoided, but one he insists people need to be prepared for.
While he says that speed is of the essence when it comes to tackling climate change, he also believes we need to slow down when it comes to certain aspects of daily life.
"We have a tendency to want to go faster all the time. For example, when you order something you want it to arrive in 24 hours. If we just accepted deliveries in three to four days, we would already hugely reduce our carbon footprint. Every time we accelerate we emit more CO2."
However, when it comes to taking action to lessen global warming, he says there is not a moment to lose. "Today we have the freedom to choose to reduce the risks to avoid extreme temperatures in the future. In the future, we will not have that freedom."
Listen to a version of this story, which was first reported by Jeanne Richard, in the Spotlight on France podcast, episode 130, here.
