I love the concept of green roofs. This worthwhile article puts forward a sound case...

The WELL Building Standard and the Fitwel certification both advocate for green spaces in or around buildings promoting gardening and time spend outdoors with nature as beneficial for fitness, wellness, social interaction and building community spirit. Also the environmental gains of providing eco-areas are a gain for the building and urban area too and reinforce the 2 of the 3 pillars of sustainability. (people, planet and profit).

“To convince investors and developers that installing green roofs is worthwhile, economic arguments are still the most important. The term “natural capital” has been developed to explain the economic value of nature; for example, measuring the money saved by installing natural solutions to protect against flood damage, adapt to climate change, or help people lead healthier and happier lives.”