Fifteen years ago green roof pioneer Charlie Miller had to convince clients to plant Sedum on their roofs. Never mind that Scandinavians began building sod roofs centuries ago to moderate indoor temperature, or that Germany began investing in green roof technology in the 1980s to manage stormwater. In North America, no one wanted to slap dirt and plants on their building, period.
Fast forward to present day North American cities, and the green roof industry is booming! So what happened? What prompted this ideological shift? As word of European and early American green roofs spread, designers began considering vegetated roofs as a tool that could provide clients with unique, sustainably-minded buildings. Demand for beautiful views and rooftop amenity spaces in dense cities furthered the trend, particularly as property values increased and urban space became more precious.
The tipping point, however, came with policy changes. The EPA now holds cities with excessive combined sewer overflows (CSOs) in violation of the Clean Water Act, forcing municipalities to clean up their acts. Innovative programs like Philadelphia’s Green City, Clean Waters emphasize managing stormwater where is falls (with green roofs, rain gardens, etc.) to prevent overloaded sewer systems. The Philadelphia Water Department simultaneously unrolled a stormwater fee structure that encourages green infrastructure by charging property owners for the impervious surfaces on their property. The carrot comes in the form of subsidies and tax abatements, which work with the stick to promote green roofs and similar improvements. Other cities with progressive stormwater policy and incentives – Portland, OR, New York City, and Washington DC – have similarly seen green roof industry booms!
What does this have to do with rooftop agriculture? Food roofs are the next frontier. Rooftop farms and gardens allow us to double down on our benefits: managing stormwater while growing healthy food and building community. It’s just that simple. Green roof policies and incentives already apply to many food roofs, and new policies specific to rooftop agriculture infrastructure are blossoming in cities like New York.
Just as Charlie Miller paved the way for green roofs in the 1990s, today’s rooftop agriculturalists are setting the stage for deliciously sustainable future. Now is the time to climb up there and plant the seeds of a green city worth celebrating.