When the world’s best footballers take the field at the 2026 FIFA World Cup later this month, they may find themselves battling more than just their opponents. A new set of scientific studies suggests that climate change could become one of the defining factors of the tournament, with 97 of the 104 matches now facing a higher risk of performance-impacting heat, potentially affecting everything from sprint speeds and recovery rates to tactics, match intensity and even player safety.
For a competition expected to attract more than 5 million spectators and billions of television viewers worldwide, researchers warn that rising temperatures are no longer merely a backdrop to the game—they are increasingly becoming part of it. The tournament, jointly hosted by Canada, Mexico, and the US, is scheduled to begin on June 11. The findings, released by Climate Central and World Weather Attribution (WWA), paint a stark picture of how a warming planet is beginning to reshape elite sport.
Heat threat looms
According to Climate Central, nearly half the matches scheduled for the tournament — 49 out of 104 — have at least a 50% probability of temperatures exceeding 28 degree Celcius, a threshold that sports scientists associate with measurable declines in football performance.
The analysis found that climate change has increased the likelihood of performance-impacting heat in 97 matches, while 26 games have seen the risk rise by at least 10 percentage points because of human-caused global warming. The most affected fixture is expected to be the Uruguay-Spain match in Guadalajara on June 26, where the probability of performance-impacting heat has climbed to 70%. Climate change alone has increased the likelihood of such conditions by 37 percentage points, the highest increase recorded among all tournament fixtures.
The implications extend far beyond discomfort. Modern football is built on relentless movement. Midfielders routinely cover 10-13 kilometres during a match, while elite players perform repeated high-intensity sprints that can determine goals, defensive recoveries and match outcomes.
Researchers say temperatures above 28 degree Celcius can reduce sprint frequency, lower the total distance covered and slow recovery between bursts of activity. “When heat impacts sprinting, recovery and overall intensity, it changes the way football is played — and not for the better,” said Norwegian international Morten Thorsby, who is expected to feature at the tournament.
Scientists warn that the consequences could be visible to fans as well. Fewer sprints, lower pressing intensity and greater fatigue could alter the pace, rhythm and spectacle of matches. Mike Tipton, a professor at the University of Portsmouth, said rising temperatures are already changing the sport.
“Playing in temperatures above 28 degree Celcius changes the game — affecting tactics, tempo and overall quality. We see reduced intensity, less sprinting and potentially fewer chances being created,” he said. A separate assessment by the World Weather Attribution suggests the challenge may be even more serious.
Players, fans at risk
The study found that approximately one in every four World Cup matches could be played in conditions exceeding heat-stress thresholds recommended by FIFPRO, the global players’ union. Researchers estimate that 26 matches could cross the 26 degree Celcius Wet Bulb Globe Temperature (WBGT) threshold, where cooling interventions are recommended, while five matches could exceed the 28°C WBGT level at which postponement is advised. The threat is not confined to players alone.
Of more than 5 million fans who are expected to attend the tournament, many are going to spend hours in open-air venues during peak summer conditions.
Climate Central’s stadium analysis found that 14 of the 16 World Cup host stadiums now experience more extremely hot summer days than when they previously hosted World Cup matches. Across repeat host cities, the frequency of extreme heat days has tripled on average.
The increase in temperature is particularly striking in Miami and Mexico City, where extremely hot June-July days now occur seven times more often than during earlier World Cup eras. Despite the growing heat threat, only three stadiums — Atlanta, Dallas and Houston — are fully climate-controlled, leaving the vast majority of players and spectators exposed to outdoor conditions.
Researchers estimate that nearly 49% of all extremely hot June-July days recorded across World Cup host cities since 1970 can be attributed to climate change driven by fossil-fuel emissions. “The World Cups of the past won’t happen again — not because the players have changed, but because the planet has,” said Shel Winkley, a meteorologist at Climate Central.
The findings come as organisers increasingly confront the reality that climate change is becoming a central challenge for global sporting events. Tennis tournaments, marathons, cricket matches and athletics competitions have all faced disruptions linked to extreme heat in recent years.
For football, however, the implications may be particularly profound. The World Cup is built on moments of explosive speed, relentless pressing and athletic endurance. Scientists now warn that rising temperatures are beginning to erode exactly those qualities.
For billions of football fans, the 2026 World Cup may offer the clearest evidence yet that climate change is no longer a distant environmental issue. It is increasingly influencing how sport is played, how athletes perform and how the world’s most-watched events are experienced. And for the first time, one of football’s toughest opponents may not be wearing a jersey.