Are we approaching the end of the Summer Olympics?

The Rio Olympics are coming to a close and they’ll likely be remembered as much for the performances of Simone Biles, Michael Phelps, and Usain Bolt as they will be for, perhaps, misguided concerns over Zika.

It seems like the Olympics are frequently an innocent bystander in issues of global anxiety, and if the theory proposed in a new research paper is right, you can add climate change to that list.

John Balmes is a professor at UC Berkeley’s School of Public Health and a co-author of the report in this week’s Lancet: The Last Summer Olympics? Climate change, health and work outdoors. 

“Our main goal was to highlight to the world that climate change is real, and it will affect our performance in hot weather, especially hot, humid weather,” said Balmes. “We thought we would use the Rio Olympics as a jumping off point to talk about future summer Olympics.”

According to the report, very few cities will be able to host the summer Olympics by 2085, due to hot and humid conditions. By too hot, the research suggests that competing in an outdoor endurance event, like the marathon, would put the athlete in considerable risk for heatstroke.

The paper only looked at cities in the northern hemisphere, and only those with a population over 600,000, but the findings are alarming. Outside of Western Europe, which still would have two dozen contenders, just two cities in Asia make the grade, none in Latin America and none in Africa. In North America, just three cities will be cool enough to be considered safe: Vancouver, Calgary and San Francisco.

If projections for climate change get worse, even those cities wouldn’t be available.

“It’s one thing to be thinking about polar ice caps receding, and polar bears not being able to have the habitat they are used to, but it is another thing for people to consider how the Olympics would be impacted,” said Balmes. “Hopefully, [they’ll] take that information and transfer it to their own lives and realize that, actually, farm workers, construction workers, other people that do vigorous work outside are going to be impacted in the future.”