The impending retirements of Roger Federer, Serena Williams and Rafael Nadal, winners of a combined 65 major singles titles, have some worried that the glory days of tennis are ending. But the sport faces a bigger existential crisis: climate change.
All sports, if they haven’t already, are expected to suffer in a warming world. Rising sea levels could flood arenas and stadiums. Increased use of artificial snow could lead to more serious injuries to skiers and biathletes. Stronger storms and wildfires could wreak havoc on league schedules. But probably few sports are doing worse than tennis. The sport follows the sun 10 months of the year and more than 80 percent of its tournaments are played outdoors. And in tennis there are no substitutions: players spend hours on the court with no partners ready to take their place while they rest.
In some ways, tennis could suffer as much as endurance events like marathon races, where athletes are always on the move and constantly exposed to heat, said Debra Stroiney, a professor of kinesiology at George Mason University.
“Running a marathon, you’re out there for hours, constantly working,” he said. “But tennis too, they’re out there sometimes three, four, five hours, depending on the match, and yeah, you sit down from time to time, you don’t hit the ball from time to time. But they are also constantly running around and moving.”
To investigate the future of tennis in a warming world, we used maximum temperature and relative humidity forecasts from five climate models produced as part of the United Nations Intergovernmental Panel on Climate Change Sixth Assessment Report. All of these forecasts assume that we continue on our current path of heavy fossil fuel use, which is expected to lead to 6 to 10 degrees Fahrenheit of warming from pre-industrial levels through the end of this century. (The planet has already warmed about 2.2 degrees Fahrenheit since the pre-industrial era, in the mid-to-late 19th century.)
Using forecasts from multiple climate models spanning a range of expectations, we were able to determine the highest temperature predicted by any of the models for each day. We calculated the average maximum temperature and the extreme maximum temperature, or a “maximum of maximum temperatures”, to give an idea of what we could expect if a heat wave occurs during a future tournament. For example, what could be the highest temperature during the 2050 Australian Open in Melbourne?
To be clear, these daily forecasts are not weather forecasts. But they do provide a window into how climate change could shift what we now think of as normal weather into new extremes.
|Tournament||Average maximum temperature*||Temperature||heat index||rel. humidity|
In the 2050 Australian Open finals, it could feel as hot as 147 degrees Fahrenheit, with an air temperature of 105.4 and a relative humidity of 58.2 per cent. When Ash Barty made Australian tennis history there earlier this year, the high air temperature at Melbourne Park was more than 30 degrees lower, at 71.
At the 2050 French Open in Paris, players could experience a heat index of 113 degrees, with temperatures reaching as high as 90. The maximum when Nadal won his 14th Roland Garros title, a record that extended earlier this month? 72 degrees
At Wimbledon, the maintenance team will have to work harder to keep the grass lush and tidy, as it could feel like 102 degrees in London in 2050. But that might seem like a relief compared to the 2050 US Open in New York, where the heat index could rise. at 145 degrees
Tennis has already experienced the dangers of a warmer planet. Croatia’s Ivan Dodig wondered if he “might even die” before withdrawing from a 2014 Australian Open match. “Impossible to play in this heat…it’s just about surviving,” Elena Vesnina of Russia tweeted during the tournament.
Last year at the Tokyo Olympics, Russia’s Daniil Medvedev voiced similar concerns: “I am a fighter, I will finish the match, but I may die,” he told the chair umpire during the game. “If I die, is the ITF [International Tennis Federation] Are you going to take responsibility?
At the 2018 US Open, Roger Federer was upset in the fourth round amid some of the most sultry conditions he could remember. “I had problems in the conditions tonight. It’s one of the first times it’s happened to me,” he said. “At some point I was also happy that the match was over.”
Players have already been in danger from the collateral damage of climate change. Smoke from wildfires that scientists say likely occurred due to rising global temperatures caused Dalila Jakupović of Slovenia to withdraw from the Australian Open 2020 qualifier she was leading. “I couldn’t breathe anymore and I fell to the ground,” she said.
The ATP, WTA and Grand Slam tournaments have extreme heat policies or ways to give players more breaks in dangerous conditions. But short of more frequent stoppages during matches, how can tennis survive on a warmer planet?
The key factor will be the core body temperature of the players. Of course, our bodies are usually around 98.6 degrees Fahrenheit, but when they heat up to between 101 and 104 degrees Fahrenheit, the risk of heat illness increases, said Ethan Hill, a professor in the School of Kinesiology and Physical Therapy at the University of Florida. At 104 degrees or higher, we are at risk of heat stroke and possible organ failure.
How a person’s body reacts to heat depends on the individual and, crucially, whether the player is properly hydrated and acclimatized to the heat. Acclimatized players tend to sweat earlier, which helps their bodies stay cooler, Hill said. But generally speaking, Hill and Stroiney said, tennis players can expect to see more heat illness in such extreme weather. “We have that known limit,” Stroiney said. “Our bodies are going to say ‘no,’ or the core temperature rises to a point where our brain is actually going to say ‘stop.'”
Tennis has ways to mitigate that risk, including hosting more indoor tournaments, Stroiney said, and fewer matches during the heat of the day, Hill said.
Tennis could also use innovative ways to cool down players, Hill said. For example, during substitutions or breaks between sets, cooling vests and fans could be deployed to lower players’ core temperature. Tournaments often provide players with ice towels and fans in extreme heat.
Hill is also encouraged by the research on the use of sodium and glycerol supplements to help support electrolyte levels and hydration, though he stressed that more research is needed, especially in extreme heat environments.
“It’s going to be incredibly important that we start developing strategies to calm people down,” Hill said. “Obviously this will become more important as the planet continues to warm and we continue to compete in these hot climates.”
Tennis officials understand the risks to players and emphasize strategies such as maintaining hydration and encouraging players to acclimatize. “When players constantly train and compete in higher temperatures, the body adapts through acclimatization and [that] it allows the body to perform at higher levels,” said Todd Ellenbecker, vice president of medical services for the ATP, through a spokesman. “Careful planning, preparation, along with optimal fitness levels, help athletes adapt to sports performance in the heat.”
Hill and Stroiney agree that acclimatization will be crucial for athletes. Within a week, acclimatized athletes can retain 2 to 3 liters more water and maintain a lower heart rate while exerting themselves, Hill said.
But it is not as simple as applying well-known strategies and expecting similar results. In more intense extreme heat, both Hill and Stroiney wonder how our typical physiological responses will fare, or if new solutions will somehow be needed. For example, athletes typically take two weeks to fully acclimatize, Hill said. “Now that the planet is warming, that could be longer,” he said.
The body also naturally moves warm blood from the core to the skin to help cool the body, he said. “That’s a pretty efficient process that gets better with acclimatization to heat,” Hill said. “But… when the planet gets that hot, will that physiological response still be effective?”
Stroiney has similar doubts, and it’s personal. He has played tennis and has run 10 marathons. But she, like some tennis players, does not do well in the heat. How will she and other athletes perform in ever-increasing temperatures?
Hill is optimistic that tennis, or the world, will change before waves of heat illness deplete the sport. “I don’t think it’s all doom and gloom,” he said. “We just have to be very aware that it’s going to get hotter.”
So, almost 30 years from now, when Federer, Williams and Nadal share their stories of Grand Slam championships, they may also be telling tales of the forgotten days of outdoor tennis.