As global temperatures continue to rise due to fossil fuel pollution, extreme heat is becoming an increasingly significant threat to elite athletes and spectators alike. Cases of heat exhaustion and heatstroke are becoming more common, putting the health and safety of those involved in major sporting events at serious risk. This growing concern is especially pressing for the Summer Olympics, where the combination of heat and humidity could make it unsafe for many of the world’s cities to host the Games in the coming decades.
According to a CNN analysis of data from CarbonPlan, a climate science and analytics nonprofit, most cities in the eastern part of the United States will exceed safe humid heat thresholds by 2050. Heat stress, measured using the wet-bulb globe temperature—a combination of heat, humidity, windspeed, sun angle, and cloud cover—indicates that once temperatures surpass 82.1 degrees, experts recommend canceling outdoor sporting events to prevent serious health risks. If current trends continue, holding the Summer Olympics in many cities will pose a significant health risk to athletes.
The implications are stark. Super-humid states around the Gulf of Mexico, such as Florida and Texas, will become inhospitable for summer sports. Even cities that have hosted the Olympics in the past, like Atlanta, which held the Games in 1996, may no longer be viable options by 2050. The situation is similar in other parts of the world: much of eastern China, including major cities like Beijing and Shanghai, as well as large portions of Southeast Asia, would exceed the safe heat stress limits.
As the risks of extreme heat grow, there is increasing pressure to reconsider the timing of the Summer Olympics. Some suggest moving the Games to cooler months, as was done in Sydney in 2000 and in Rio de Janeiro in 2016. While cities in northwest Europe, such as London, Oslo, and Stockholm, may remain viable for summer events, many Mediterranean cities, including Palermo in Sicily and Seville in Spain, will likely surpass safe heat levels. High-altitude cities in South America could also become more attractive as global temperatures rise.
Looking ahead to the 2036 Summer Olympics, more than 10 countries have expressed interest in hosting the event. However, only six have made their bids public: India (Ahmedabad), Indonesia (Nusantara), Qatar (Doha), Turkey (Istanbul), Poland (Warsaw), and Chile (Santiago). According to CarbonPlan’s data, nearly all of these cities will breach the heat stress limit at some point during the year. Only Santiago is expected to remain below the threshold year-round, making it the safest option in terms of heat risk.
Oriana Chegwidden, a climate scientist with CarbonPlan, noted that the worst heat of the year often coincides with when the Summer Olympics are typically held. She suggested that if cities with high heat risks are chosen to host the Games, simple measures could mitigate the dangers. These measures might include holding events during cooler parts of the year, scheduling competitions at night or in the early morning, or selecting cities with naturally cooler climates, such as those at higher elevations.
Cities that have previously hosted the Summer Olympics, like Beijing, Athens, Rome, Atlanta, Tokyo, and Seoul, are expected to be too hot to host the Games safely by 2050. Even Sydney and Brisbane in Australia, along with Rio de Janeiro, will be technically too hot, but they could still host the Games during their cooler seasons.
