Levi’s Stadium had only been operating for a day before San Francisco 49ers fans noticed something was terribly wrong.
The $1.2bn (€1.09bn) venue had been heralded as one of the most environmentally friendly and technologically advanced venues in the NFL when it opened in 2014, so the team probably wasn’t expecting questions on why the stadium was so unsuitable after a single pre-season game.
One side of the stadium was left open to the elements to take advantage of warm, dry summers and mild winters in California. But when fans placed 60 emergency calls at the stadium and two people were taken to the emergency room after a game held in August, team president Al Guido saw fit to explain the absence of any protection from the sun.
After blaming ‘some unseasonably warm days’ for the fan discomfort, he explained that the venue’s proximity to the flight path of the nearby San Jose airport would make it difficult to add any shading to the exposed areas.
In October 2024, another one of those ‘unseasonably warm’ days struck a 49ers home game against the Arizona Cardinals. Fans on the uncovered side of the stadium were forced to watch the game from the concourses to escape 40-degree heat. Some fans collapsed from the heat in the upper decks, while others were treated for heatstroke in shaded areas.
Extreme weather conditions are an increasingly major threat to the future of outdoor sport. And while Flat Earthers might resist the idea of climate change, architects and engineers are more ready to see the story as an emblem of the changing stakes in venue design.
Chris Dite, UKIMEA sports architecture leader for London-based architecture, planning and engineering practice Arup, says he is having to factor a much wider array of climate variables into their plans these days.
“The first sketch on the piece of paper is thinking much more about environmental conditions than it did 25 years ago,” he says. “We used to think about how to make sure light gets to the pitch to keep the grass growing. Making sure the sun didn’t shine in the TV cameras was the next step up from that. Now we’re into: ‘How do we make sure that this thing that we’re investing in is good for the next 25-30-40 years?’ which is the natural lifetime of a sports building.”
As global sports rights-holders seek to host more events in the Middle East, the main problem for those charged with delivering new sports venues in the region is dealing with the blistering heat.
In more northerly European climes, Dite says extreme rainfall is now the number one problem. In areas like Mexico and North America, which will play host to the 2026 Fifa World Cup, the challenge is heat combined with humidity.
The architect, who previously lived and worked in tropical Singapore to deliver the 55,000-capacity Singapore Sports Hub, says the latter combination is particularly tricky to design for.
“Singapore is on the equator; they know it’s humid, they know how to deal with it,” he says. “But where there used to be quite a thin band around the middle of the world, that band is expanding and there’s certain places in the world that just aren’t used to it.
“They’re used to dealing with dry heat in the Gulf, but now they’re getting wet heat, and wet heat is much more difficult for a building to deal with than dry heat.”
Air conditioning
To address the high temperatures at the 2022 Fifa men’s World Cup in Qatar, seven of the eight stadiums were equipped with air conditioning to keep fans cool during games.
But David Jarratt, sustainability design lead for Populous in the EMEA region, says the architecture and engineering communities are taking an increasingly dim view of this carbon-intensive practice, which wasn’t necessarily appreciated by fans in attendance.
“They integrated a lot of air conditioning into those stadiums and they actually found that by operating them, people were too cold. As the event moved on, they actually didn’t use them as much,” he says.
Jarratt says designers working in the Middle East often look to use a combination of solar shading from lightweight fabrics and ‘passive cooling’. This uses the contours of a building to draw airflow through seating areas in hotter conditions, rather than relying on the ‘active’ cooling deployed in Qatar. Such an approach also helps to reduce the operational cost of the buildings.
For more risk-averse clients, however, he proposes future-proofing projects so that fans and cooling could be added at a later stage – an approach he deployed in an earlier role designing public spaces like train stations.
“I’ve looked at natural ventilation strategies in stations where we’ve incorporated or made it that you can integrate fans later. But we’ve proved through the design process – using detailed modelling tools, CFD [computational fluid dynamics], thermal analysis, dynamic thermal analysis and modelling – that you don’t need it. Natural ventilation is the best form of getting moving air through a space.”
If designers have been guilty in the past of taking stadium designs that are appropriate for a particular climate and transplanting them elsewhere, Dite believes an appreciation of local architectural customs will become more prevalent as the planet heats up.
“I think as you start to reflect a little bit more on building what’s appropriate for a place, rather than building an international-style building, it puts much more onus on having more of an appreciation of how that culture has managed
the environment historically,” he says.
“What we’re finding is, if we want to keep a stadium cool, it’s actually the same as keeping a church cool, or it’s the same as keeping a convention centre cool. And really a lot of that is to do with being appropriate, tucking it into the ground, making sure you don’t do big open spaces that have sun directly on them.”
Rain
While the 49ers’ and Fifa’s experiences are emblematic of the challenges of dealing with extreme heat, Manchester United has arguably become a symbol of the challenges of dealing with extreme rain.
A chronic lack of investment in the team’s Old Trafford stadium has left it particularly vulnerable to the elements in Britain’s wettest city. During a game against Arsenal in May, torrential rain caused the roof to leak, soaking the fans below in the Stretford End and East Stand. The Old Trafford ‘waterfall’ has now become an easy way for rival fans to mock the club’s wider image of dysfunction.
In September, the club announced plans to address the long-standing issues by entering a partnership with Trafford Council and the Greater Manchester Combined Authority to explore options for a new or redeveloped stadium.
Jarratt says the new venue will have to respond to a different set of challenges to those operated in the Middle East, emphasising that the solar shading designed for a hotter climate would be inappropriate in rainy Manchester.
“Lightweight roofs don’t necessarily work in the UK, where you get flash storm events. But you might also, at the same time, have freezing cold temperatures that are freezing that water and creating much heavier loads on the roof.”
Jarratt continued: “You’re starting to think, we need to support much heavier loads and have much stronger systems, much bigger down pipes, and much bigger hydraulic systems to accommodate that.”
A lot of venue designers think it is better now to embrace wet conditions rather than trying to fight the rising tide. A case in point is Murrayfield stadium in Scotland, which is surrounded by a dam to protect it from the Water of Leith, the main river flowing through central Edinburgh. At times of excessive rain, gates in the dam open to manage waterflow around the venue and protect it from flooding.
Dite says: “You deal with water in a way that you’re trying to move it into lesser [areas] and especially car parks or surrounding open spaces, rather than coming across your field of play or where your spectators may be.”
He adds: “Some of the cricket stadiums in India that are close to rivers accept that there’s a cricket season, then there’s a wet season, and things are going to get inundated. Nothing’s built below two meters off the ground. You let it come through, you let it dry out, you play cricket in your cricket season.”
Cricket is unusually vulnerable to a changing climate because, unlike football or rugby, it is rarely played in rainy conditions. Dite says the fact a large number of grounds are built in city centres alongside near rivers is also a problem for the sport.
There isn’t a ready-made architectural solution, however, as in most cases it would be too costly and impractical for all stadiums to be covered. To date, Marvel Stadium in Melbourne is the only cricket venue in the world with a roof and to have staged an indoor international match.
Jarratt says Populous quickly concluded that a roof would have been unfeasible for the 132,000-seater Narendra Modi Stadium in Ahmedabad, India, a project that the company delivered in 2020.
Instead, angled coverings over each stand provide partial relief for spectators. Still, on particularly hot days, fans pack themselves into the stadium’s shaded areas and away from seating exposed to the sun.
“I’ve got a picture of the Ahmedabad Stadium in front of me, and it’s a very big expanse,” Jarratt says. “Even if you did create some form of structure to go from one side to the other, it would be a significant weight. As soon as a breeze comes along, it would really pick it up and act like a sail.”
The solution at Modi Stadium has been more matches played during the evening and at night, shielding players and fans from extreme temperatures.
Back in San Francisco, however, the 49ers have no such option. The team will continue to play most of their regular season games at 1pm local time for almost another decade, in accordance with NFL broadcast windows through to the end of 2033.
Fans at Levi’s Stadium can do little but hope for fewer ‘unseasonably warm days’ over the next decade.
