OPENING Round match between Australia 1-8 Japan during the Tokyo 2020 Olympic Games at the Fukushima Azuma Baseball Stadium in Fukushima, Japan. 鈥 REUTERS

The muggy heat-swaddling Tokyo may be a forerunner of Olympic life to come, experts say, urging a rethink to make the world鈥檚 oldest sporting spectacular fit for a fast-warming planet.听

The Olympics kicked off in the Japanese capital last week after a year-long delay due to the pandemic, with organizers banning spectators from venues and enforcing a slew of measures to keep the coronavirus at bay.听

While worries over听coronavirus disease 2019 (COVID-19)听have overshadowed other concerns, Japan鈥檚 heat and humidity 鈥 where temperatures can exceed 35 degrees Celsius 鈥 also show how future Games will need to grapple with extremes as climate change bites.听

鈥淭okyo 2020 will serve as a model for future hotter Olympics and other summer sporting competitions,鈥 said Yuri Hosokawa, an expert on sport and heat risks at Japan鈥檚听Waseda听University.听

鈥淟eading up to the Games, many athletes around the world have trained under humid heat to acclimatize their body to the environmental stress they will experience in Tokyo,鈥 she told the Thomson Reuters Foundation.听

Tokyo鈥檚 mean annual temperature has risen by 2.86掳C since 1900, about three times as fast as the world average of 0.96掳C, says the British Association for Sustainable Sport.听

Ms. Hosokawa said some new heat mitigation measures, such as on-site medical treatment for serious heat stroke, instigated for Tokyo, could help shape how best to compete in oppressive heat.听

Forget running fast or jumping high 鈥 just watching many outdoor sports is now a feat as climate change brings intense rain and heatwaves, spawning hospitalizations, and canned events.听

The Tokyo Games, from July 23 to Aug. 8, coincide with the year鈥檚 hottest temperatures in Japan.听

Just last Friday, a Russian archer fainted in the heat during a qualifying Olympic round.听

On Wednesday, tennis world No. 2 Daniil Medvedev said a player 鈥渃an die鈥 in the heat that is stifling Tokyo. The sports鈥 governing body later agreed to delay match start times in response to similar complaints by other players.听

鈥楬EAT ON THE AGENDA鈥

Hoping to beat the heat, organizers have deployed a host of tools 鈥 from mist-spraying stations to cooling vests 鈥 as well as handing out salt tablets and ice cream to weary volunteers.听

The city, known as an innovation hub, has also deployed tech to help mitigate man-made change: be it roads that reflect heat or pavements that absorb water to stay cool, while moving the marathon and race-walk events to the cooler north.听

But climate researchers urged the Olympics authorities to think way further out and change the shape of future summer Games, either by shifting events to cooler seasons, building in more breaks or changing running orders for the fierce weather.听

鈥淭hey have to start putting heat on the agenda. They鈥檙e going to have to start thinking about the best time of the year and the best locations to have these events,鈥 said Mike Tipton from Britain鈥檚 University of Portsmouth.听

Mr. Tipton, a professor of human and applied physiology, said the heat was not only diminishing the elite competitors鈥 performance but also posed grave health risks.听

鈥淧eople who follow sport should appreciate what climate change is doing to their sport, entertainment,听and spectacle. You just won鈥檛 have people performing at the same level, in endurance events for example,鈥 he added.听

Makoto听Yokohari, an advisor to the Tokyo Olympics, said high-tech measures, such as the heat-blocking pavements, could only have 鈥渓imited鈥 effects and it would be better to postpone.听

鈥淲hen it comes to this combination between the temperature and the humidity, I have been warning that Tokyo is the worst in Olympic history,鈥 said Mr.听Yokohari, a professor on green urban planning at the University of Tokyo.听

Mr.听Yokohari, who has analyzed data back to the 1984 Olympics in Los Angeles, urged the organizers of the next summer Olympics 鈥 Paris in 2024 鈥 to act early and address potential challenges.听

France saw record heatwaves in 2019, with temperature jumping to a high of 46C, causing about 1,500 deaths.听

鈥淚f that happens again… then I鈥檓 sure the situation in Paris (2024) will become even worse than Tokyo,鈥 said Mr.听Yokohari.听

Possible measures: using shade for outdoor events or holding the marathon at midnight when temperatures dip, he added.听

ADAPTATION

The International Olympic Committee said in e-mailed comments that it would take into account 鈥渇lexibility and adaptation to the consequences of climate change鈥 in planning future events.听

鈥淎 wide range of measures鈥 are being taken by Tokyo to mitigate the heat, it added, such as moving locations for the marathon and shifting start times for others.听

Ms. Hosokawa of听Waseda听University cautioned that delaying the summer Games to cooler seasons may not work as events such as the triathlon and beach volleyball are made for summer.听

In future, she said, international sports federations would need to agree on what environmental conditions would lead to automatic cancellation of events or races.听

鈥淏y knowing the upper threshold, athletes, spectators and stakeholders can train and plan accordingly and share the same expectations,鈥 she added. 鈥斕Beh Lih Yi/Thomson Reuters Foundation