Cities with Gardens on the Roofs

I've always been fascinated with the architecture that includes green space into the design. It started with Le Corbusier's Five Points of Architecture that were based on the new concrete and steel construction. The second point is a roof garden: "The flat roof can be utilized for a domestic purpose while also providing essential protection to the concrete roof." (Wikipedia) Only a handful of buildings have followed through with this bullet point. Having a garden on the roof of a building provides insulation in the winter and shade in the summer which will reduce HVAC costs. The footprint of the building won't just be a scar on the landscape but just an elevation of such. It would provide a relaxation/break area for employees/residents/occupants of the building. It can be built with flora that doesn't require more water than is provided with natural rain. It will improve the aesthetics of a city if more buildings had gardens on their roofs. 

Imagine flying into a city where green capped each tall building. Where the tall beams of stone and concrete rose from an actual urban jungle. Where the air was cleaner and fresher due to organic recycling of the plants. Where cities could start supporting themselves on the gardens on their roofs if they chose to grow vegetables and fruits. 

Small scale farming needs to return in order to protect our food supply from altering beyond what our bodies are capable of ingesting. That's the number one reason the gluten-free fad is becoming to popular (if not mandatory now for a large and growing part of the population). We've altered our wheat into something that we can't eat. So small scale farming can assist with that, keeping foods local, natural, and accessible. The small scale movement can also be utilized in cities if places like apartments were to start offering and encouraging gardens, individual or community. Roof top gardens would be a perfect place for that.

Architects have been pushing for these designs recently. I've seen a lot of cool work put into the idea of vertical farm, vertical forests, using the unused real estate on the roofs and sides of buildings. They want to incorporate nature back into the urban environment. I absolutely agree with them. We just need to find a cheap solution to such a design so that architects can sell the idea and all of its benefits to those who own the buildings. 

I want to see the steel, concrete, and glass cities that I do love, the urban environment that I crave, to be crowned with garlands of green on every roof top so that you can barely see the pattern of the city underneath from a bird's eye view.