A coalition of 20 leading international scientists has issued a stark warning to Fifa, declaring that the current heat safety measures for the 2026 men's World Cup are insufficient and could expose players to serious harm. In an open letter coordinated by the New Weather Institute, experts in health, climate, and sports performance argue that the governing body’s guidelines lag behind established science, leaving a critical gap in athlete protection during the tournament set to be hosted across the United States, Canada, and Mexico.
The 2026 edition, which will expand to 48 teams for the first time, is scheduled for June and July—peak summer months in North America. Researchers have identified that 14 of the 16 stadiums could see temperatures soar to dangerous levels, with parts of the southern US and northern Mexico regularly hitting daytime highs in the mid-30s Celsius and occasionally approaching 40°C. When humidity, sun exposure, and wind are factored in, the risk of extreme heat stress on players becomes alarmingly high.
The scientists’ letter calls for an urgent overhaul of Fifa’s approach. Key demands include delaying or postponing matches when the Wet Bulb Globe Temperature (WBGT)—a composite measure of heat and humidity—exceeds 28°C, extending cooling breaks to at least six minutes, and providing improved cooling facilities. They also urge Fifa to align with the standards proposed by the global players’ union Fifpro. “Player safety is an immediate and urgent concern because things can go wrong very quickly when people overheat,” Andrew Simms, director of the New Weather Institute, told BBC Sport. “We’re worried that Fifa is playing recklessly with the health and safety of players.”
Fifa has already announced mandatory three-minute cooling breaks in each half for every match, along with climate-controlled benches for substitutes and technical staff. It says a “tiered heat mitigation model” will be applied, with real-time WBGT monitoring and dedicated meteorological support. Tournament scheduling has also been designed to limit matches during the hottest periods and prioritize covered stadiums for warmer fixtures. However, the signatories, including Professor Douglas Casa of the University of Connecticut, argue these measures fall short. “The hydration break in each half absolutely needs to be longer than three minutes—at least five minutes for each break and preferably six,” Casa said. “We hope this open letter convinces Fifa to update its heat guidelines before the World Cup.”
A WBGT of around 28°C is widely considered the threshold where heat stress becomes a significant concern for elite athletes, roughly equivalent to 38°C in dry heat or 30°C in high humidity. New analysis from the World Weather Attribution (WWA) reveals that the risk of such conditions has nearly doubled since the 1994 World Cup in the United States due to climate change. The study suggests around a quarter of matches in 2026 are likely to be played above 26°C WBGT, while about five games could exceed the 28°C mark considered unsafe by Fifpro.
Heat is not the only weather threat; summer in North America also brings thunderstorms and potential poor air quality from wildfires. The combination puts additional strain on players and organisers, making adaptive scheduling and clear health protocols essential. Beyond the athletes, Fifa has outlined fan-focused measures, such as allowing sealed water bottles, activating misting systems, and expanding shaded areas, but experts insist player welfare must be the priority.
If the current guidelines remain unchanged, the tournament could see matches played in conditions that international researchers describe as “impossible to justify.” The letter emphasizes that heat-related illnesses, from cramps to potentially fatal exertional heat stroke, can escalate rapidly without adequate cooling and rest. The signatories stress that updates must be grounded in the latest science, not outdated assumptions.
Fifa declined to comment directly on the letter but reiterated its commitment to safety, stating it would “continue to monitor conditions in real time and apply contingency measures where necessary.” The federation added that kick-off times have been adjusted based on climate data and that rest days are maximized. Yet for the group of 20 experts from the UK, USA, Canada, Australia, and Europe, tangible changes are needed before the opening whistle.
As the countdown to the 2026 World Cup continues, the pressure mounts on Fifa to reconcile its tournament ambitions with the stark realities of a warming planet. The scientists’ warning underscores a broader challenge for global sport: how to protect athletes in an era of increasingly extreme weather. Whether their recommendations prompt a last-minute policy shift remains to be seen, but the message is clear—failure to act could put the world’s best footballers at unnecessary risk.
Based on reporting from BBC Sport.