The World Cup has returned to a radically hotter America

Dangerously hot temperatures are blanketing the central and eastern United States as the soccer tournament enters its knockout rounds, putting tens of millions of people at risk. Roughly a quarter of all matches since the start of the games are expected to be played in hazardous heat, according to an analysis by World Weather Attribution, which models how climate change influences extreme weather events. It also warns that the wet bulb global temperature — a measure of temperature, humidity and factors affecting heat stress in the human body — could rise high enough to justify postponing some games. Sticky, hot weather is not unusual in North America during summer. But extreme heat has intensified since the U.S. last hosted the World Cup in 1994. “Around half of human-caused climate change has occurred since the World Cup was last hosted in North America in 1994. As a result, the climate that the tournament is being played in today has fundamentally shifted in just 32 years,” Joyce Kimutai, an extreme weather and climate change researcher at Imperial College London and lead author of the WWA study, said in an email. Players aren’t the only ones that are affected. Fans often spend hours in stifling heat while attending outdoor celebrations or watch festivals. Stadium workers are also at risk. Organizers have attempted to reduce the threat by installing cooling stations and scheduling some games at off-peak heat hours. But the current heat wave could hit the games hard. The National Weather Service estimates that more than 175 million people will endure temperatures this week that put them at major or extreme risk of heat-related health impacts. Some of the places facing the greatest dangers include World Cup host cities like Philadelphia, New York and Atlanta, where street parties filled with sweaty crowds and free-flowing alcohol put fans at greater risk of heat illness. “A whole bunch of warm bodies standing close to each other does make it more difficult to cool d