Lionel Messi and Cristiano Ronaldo may have to encounter an unusual opponent in the upcoming FIFA World Cup — searing heat.

A report prepared by Climate Central, an international nonprofit, has pointed out that climate change is likely to affect players’ performance at the World Cup.

“Climate change is increasing the likelihood of performance-impairing heat during the 2026 FIFA World Cup, according to a new Climate Central analysis. By examining the odds of temperatures exceeding 82.4°F (28°C) — a threshold linked to declines in player performance — researchers found that 97 of the 104 scheduled matches now face a higher probability of encountering these conditions,” the report stated.

“Nearly half of the matches have at least a 50 per cent likelihood of experiencing heat that can impair performance. In 26 of those matches, climate change increases the likelihood by at least 10 percentage points,” the report added.

According to available data, climate change is most likely to affect the June 26 match between Uruguay and Spain at Guadalajara in Mexico.

“Previous research shows temperatures above 82.4°F can reduce sprint frequency, total distance covered, and recovery time, impacting not only player performance and safety, but also match tempo, tactics, and overall style of play,” the report pointed out.

“The World Cups of the past won’t happen again — not because the players have changed, but because the planet has,” stated Shel Winkely, meteorologist at Climate Central.

Weather experts, players and sports experts are concerned.

John Toohey-Morales, an honorary member of the American Meteorological Society, said that in football, a typical midfielder runs well over 10km for each match.

“It’s a high-intensity effort, with directional changes and short bursts of acceleration. Climate Central’s analysis shows how these elite athletes will likely be slowed by hotter temperatures, which are being boosted by climate change,” he said.

Norwegian footballer Morten Thorsby said the analysis made it clear that rising temperatures not only posed a serious health risk for players and fans
but were also starting to affect the quality of the game itself.

“When heat impacts sprinting, recovery and overall intensity, it changes the way football is played — and not for the better,” Thorsby said. “That’s exactly why I signed the players’ letter to FIFA last week. We need to take these risks seriously,” he added.

Professional football players from 21 countries recently submitted an open letter to FIFA demanding stricter heat safety protocols for the 2026 World Cup. Over 100 current and former athletes, supported by climate scientists, complained to FIFA that current heat safety thresholds were inadequate and put players at extreme risk of heat stress.

Professor Mike Tipton, a sports and health expert at the University of Portsmouth, agreed with the players. “Playing in temperatures above 28°C changes the game…. We see reduced intensity, less sprinting and potentially fewer chances being created. As temperatures climb further, the risks also increase. Prolonged exposure and dehydration can lead to heat exhaustion or even heat stroke, particularly in high-stakes matches where players are more likely to push beyond their natural limits,” Tipton said.