At noon on March 4, 2017, the Denver Green Roof Initiative held its inaugural event at Cheesman Park. No one but the group’s founder, Brandon Rietheimer, showed up. He hoped the people of Denver would get behind his initiative to require all buildings 25,000 square feet or larger to build green roofs. To get it on the November’s ballot, Rietheimer needed the signatures of 4,700 Denver voters. He circled the park with a clipboard three times before he got the nerve to walk up to a stranger. “Who’s backing you?” someone asked. Rietheimer’s answer sounded like a question: “Me?” 

Rietheimer had arrived in Denver from Pennsylvania four years earlier, a 26-year-old in an overpacked car, hell-bent on changing his life. He had wanted to escape “the one bar in my hometown where everyone goes every night and gets drunk,” his “borderline racist friends” who didn’t know he was part Korean, and his exhausting food-service job. Rietheimer had started cooking professionally at 15 and dropped out of school at 17. He’d worked “everywhere”—Friendly’s, Chili’s, Eat’n Park, Buffalo Wild Wings.

In early 2017, Rietheimer was cooking part-time at a Denver Red Robin. Before the 2016 election, he “had feelings about politics but never protested.” Afterward, he was angry about Trump’s victory but also inspired by Bernie Sanders’s call to act locally. So, when he read about Toronto’s groundbreaking 2010 green roof mandate, he wondered why it couldn't happen in Denver, a city with the third-worst heat-island effect in the country; its core can feel five degrees hotter than nearby rural areas. He learned that rooftop gardens could cut summertime heat absorption through a building’s roof by more than 80 percent, also reducing the energy used for cooling. 

Rietheimer was also inspired by a new recreational marijuana law that the people of Denver approved in 2016. He realized that any local citizen could refer a question to the ballot for a vote. Including him. 

Rietheimer decided to draft a green roof policy for Denver. “I basically stole the wording from Toronto,” he says. Except Rietheimer made Denver’s policy stricter than Toronto’s. Whereas Toronto requires that all new large buildings add green roofs, Rietheimer extended Denver’s mandate to existing buildings too. “I figured, if we’re going for it, might as well go all the way.” He also included solar panels as an alternative to rooftop gardens. 

That March day in Cheesman Park, three petitioners showed up two hours late. The campaign remained small: Over the next six months, a total of 60 volunteers helped collect signatures. Once the initiative made the ballot, Denver mayor Michael Hancock spoke out against it, saying it went “too far too fast.” The campaign raised $21,000, compared with its opposition’s $249,000.                

As Rietheimer prepared for the election, a shift supervisor at the Red Robin quit. Rietheimer asked; he got the job. In October, a managerial position opened up. He asked again and landed another promotion. “I realized that if no one’s going to ask, I have to go for it, even if I might not get it,” he says. “That’s how it is with anything.” 

In November 2017, Rietheimer’s ballot initiative asked Denver voters if they wanted their city to adopt the strictest green roof policy in the country. The majority of them said yes.