Vous pouvez dormir dans cette chaleur ?

European heatwaves have led to widespread sleep disturbances, with many people reporting difficulty falling asleep and staying asleep through increasingly hot nights. In June, record-breaking temperatures across western Europe prompted a study in the United Kingdom showing that 65 percent of adults reported being awake for three or more hours each night during the heatwave. This disruption has raised concerns among health professionals about its impact on both physical and mental well-being. The phenomenon of sleeplessness is becoming more frequent due to longer and hotter summers driven by climate change. Europe, which is warming faster than the global average, more than twice as fast, has become one of the key regions affected by this issue. Nighttime temperatures have reached unprecedented levels, with one weather station in Saxony, Germany, recording a tropical minimum nighttime temperature of 29.4 degrees Celsius in June. According to the World Weather Attribution organization, such extreme high nighttime temperatures are now 100 times more likely due to climate change. Research conducted by an international team of scientists analyzed data from nearly 318 million nights of sleep recorded by over 165 million users of wearable sleep-tracking devices. The findings revealed that when nighttime temperatures rise from around 12 to 27 degrees Celsius, there's a 40 percent higher chance that individuals will get less than six hours of sleep per night. This lack of sufficient rest can impair cognitive functions, memory, and emotional balance, according to Ty Ferguson from the University of Adelaide in Australia, who studies potential health and social consequences of sleep disruptions caused by climate changes. In addition to affecting mood and attention, disrupted sleep patterns can increase the risk of diabetes, depression, heart disease, and even obesity, as noted by Ferguson based on well-established medical research. The implications extend beyond individual health, raising broader concerns about societal impacts as sleep deprivation becomes more common. Bowen Chu, an author of a study published in March examining possible economic consequences of gradual loss of sleep among children due to climate change, emphasizes that sleep is a fundamental physiological need essential for immune system function, mental health, and daily well-being. Unlike traditional climate change research focused on extreme weather events, studying sleep loss offers insights into the cumulative effects of rising ambient temperatures on everyday life and health worldwide. Kelton Minor, an external professor at the University of Copenhagen, highlights that nighttime temperatures are increasing faster than daytime ones. His research team, along with the World Sleep Society, has called for the establishment of a global working group to better understand and prepare for the growing prevalence of sleep loss in a warmer world. Nighttime heating occurs partly because clouds absorb heat and radiate it back toward Earth after sunset, unlike daylight when they reflect sunlight away. Studies show that cloud patterns are changing in ways that further accelerate global warming. Kim van Daalen, co-author of a recent paper titled “Sleep Loss in a Warming World,” notes that sleep loss may not receive enough attention in discussions about the impacts of climate change. She explains that while it does not create dramatic incidents or visible damage, the long-term consequences could be significant. As the planet continues to warm, the challenge of maintaining adequate sleep will grow, posing new challenges for public health and wellbeing.