Most Influential Projects 2022

44 Climate Pledge Arena

Climate Pledge Arena

For setting a new sustainability standard for the sports and events industry

“Everyone loves to talk about being carbon-neutral, but it’s really hard and really expensive. We’re trying to set a precedent others will follow,” Tim Leiweke, CEO of developer Oak View Group (OVG), told Time magazine. Bold words for a bold project: A US$1.15 billion push to turn Seattle’s 60-year-old stadium into the world’s first net-zero carbon arena in the world—while also doubling its size.

Leiweke also called it an “impossible journey,” which wasn’t far off. Project leaders contended with the preservation of a landmarked roof, a major shift in project scope, budget overages and, of course, pandemic-related complications throughout the course of the build. But the team ultimately prevailed, and the 18,100-seat Climate Pledge Arena celebrated its grand opening in October 2021—and now serves as home to two professional athletic teams and a host of concerts from Billie Eilish to Bruce Springsteen. 

Here’s how project leaders melded iconic architecture with green infrastructure to transform Climate Pledge Arena into the world’s first professional sports venue to be certified carbon zero by the International Living Future Institute: 




Raising the Roof

Designed by renowned architect Paul Thiry for the 1962 Seattle World’s Fair, the original stadium’s sloped roof and exterior walls and supports were granted city landmark status in 2017 and federal landmark status the following year. That meant the design by architectural firm Populous had to preserve and incorporate these original elements. But the landmark status came with benefits: OVG snagged US$50 million in federal tax credits. 

How’d they pull it off? Construction contractors Mortenson salvaged the 44 million-pound (20-million kilogram) topper and temporarily suspended it using 4,000 tons of steel. At the same time, the team used digital tools to simulate the built environment and then essentially constructed a brand-new arena underneath—a process project leaders likened to building a ship in a bottle. Once everything was in place, the crew then installed 10,000 tons of steel to permanently support the roof above the arena. 


The Climate Pledge


Switching Gears to Greener Goals

The original project scope didn’t include such rigorous attention to sustainability. Mortenson was already 15 months into construction when Amazon founder Jeff Bezos announced the Seattle-based e-commerce behemoth had bought the naming rights to the arena, complete with a grand vision. “Instead of calling it Amazon Arena, we’re naming it Climate Pledge Arena as a regular reminder of the urgent need for climate action,” Bezos wrote on Instagram. “It will be the first net zero carbon certified arena in the world.” 

With that news, a quick pivot had to be made to incorporate a deeper shade of green into the already in-progress project plan. One of the biggest overhauls was switching to renewable energy, with gas components swapped out for electric—all the way down to the french fry cookers. To aid its efforts, the team engaged early with local energy provider Seattle City Light to troubleshoot its new—and ongoing—utility needs. 

Working With the Elements

Given its location on the picturesque Puget Sound, project leaders added water preservation as a focal point of their new sustainability plans. Taking advantage of Seattle’s notoriously wet climate, they devised a “rain to rink” system, in which water from the roof collects in a 15,000-gallon (56,781- liter) cistern to be recycled into ice for resurfacing the hockey rink. (Naturally, rink maintenance is conducted by an electric—not gas-powered—ice resurfacer.) Thoughtful water usage prevails off the ice too, with waterless urinals and ultra-efficient showers. 




Building Sustainable Stakeholders

While dozens of eco-friendly initiatives have been incorporated into the building’s architecture, the project team also wanted to find a way to signal to patrons the role they could play in furthering sustainability aims. Infographics throughout the space inform guests about the building’s green features, while sorting stations encourage proper disposal of waste. 

Water bottle filling stations are also plentiful, reducing the need for single-use plastic, which will be eliminated from the arena by 2024. And to encourage cleaner transportation to and from events, the arena is equipped with electric vehicle charging stations, a bike valet and a connection point to the Seattle Center Monorail transportation system.