In less than a month, the world’s attention will shift to one of the biggest sporting events on the planet: the FIFA World Cup. As fans prepare to travel to stadiums across the United States, Mexico and Canada, scientists are warning that dangerous heat linked to climate change could create unsafe conditions for both athletes and spectators.
A new analysis warns that dangerous levels of heat and humidity are now nearly twice as likely as they were the last time the U.S. hosted the World Cup, in 1994, largely due to human-driven climate change.
The study, conducted as part of the World Weather Attribution initiative, found that more than two dozen matches this summer are expected to be played under potentially dangerous heat-stress conditions.
“Matches this summer will be played in conditions made hotter by climate change, putting players and fans at risk,” Simon Stiell, executive secretary of the U.N. Framework Convention on Climate Change, said in a statement obtained by Mongabay.
Researchers used the Wet Bulb Globe Temperature (WBGT), a measure of heat stress in direct sun that combines temperature, humidity, sunlight, wind and cloud cover to identify trends across several host cities. A WBGT above 26° Celsius (79° Fahrenheit) is considered risky, while temperatures above 28°C (82°F) are deemed unsafe for play, according to the study. During the upcoming tournament, the WBGT for 26 matches is expected to reach or exceed 26°C. In 1994, there were likely 21. Five matches could surpass the dangerous 28°C threshold this year, compared with three during the 1994 tournament, according to the report.
