Devlin's manifesto, which was published earlier today, involves replacing every parked car with a tree.
She also proposes a code of conduct for architects and designers, who would promise "to do no harm to the planet as they practice".
The manifesto is set 15 years in the future, with Devlin looking back on the great progress humans made since the COP26 conference.
"The trees and shrubs have attracted a diverse range of species including birds and butterflies into city centres," her manifesto states. "All buildings are now powered by renewable energy."
"People and goods move around the city centres along tree-lined pathways on foot, on cycles, using cycle-shares, e-bikes, e-scooters, electric mobility scooters, trams, electric buses and subways."
Devlin is a British artist and designer best known for creating large-scale sculptural installations and performances. Her recent projects include Forest for Change at Somerset House and the UK Pavilion at the Dubai Expo 2020.
Dezeen 15 is a three-week digital festival celebrating Dezeen's 15th birthday. Each workday, a different creative will present a manifesto setting out an idea that could change the world over the next 15 years.
Click here for details of all 15 contributors.
The portrait of Devlin is by Alfonso Duran.