Urban areas are sprouting a new trend, green roofs, and gardens atop buildings. When we think of gardens, we don’t typically picture them growing atop large masses of steel; in fact, this seems illogical. However, urban planners, city officials, and landscape architects are changing this narrative.
In recent years, many buildings have been experimenting with green roofs to see how they effect buildings and what they have found is that they provide a natural cooling system to the city below, bring pollinators to urban areas, and grow exponentially for the enjoyment of the city’s residents (among various other benefits).
The EPA provides a thorough look into the science behind green roofs starting that the green roof temperatures can be 30˚F-40˚F lower than other roofs all while reducing city-wide wind temperatures by up to 5˚F. This means that the buildings with green roofs are spending significantly less on energy usage in the summer, because the building does not heat excessively because of evapotranspiration. The EPA studies show that the average annual energy savings are $0.23 per square footage of the roof. These studies also found that 2016, through a industry stakeholder sample, there were over 900 green roofs that were equivalent to 40 million square feet in 40 states.
In addition to reduced energy use, green roofs can bring back pollinators to urban areas; these are places you would not typically see pollinators inhabiting. This is because they provide more green spaces and habitats in the city (urban ecology). Bees can stop over in cities in between the habitats where they get their pollen. They can also make homes in these green roofs and eat from the pollen-rich flowers like lavender, mints, and coneflowers (all of which are also edible for humans as well). When areas have more pollinators, the environment reaps many benefits like the spring season, plant harvest/pollination, food preparation, wax production, and antibacterial properties. Bees and other pollinators can be a big indicator of the health of an ecosystem.
Pollinators are not the only ones getting food from these green roofs, humans and animal also benefit from their growth. Most green roofs are also urban gardens that provide a plethora of food for city residents that would otherwise have to import it from farms and places that may not be local to them. The rooftop atmosphere is not what you would expect for ideal growing conditions for food, but surprisingly many herbs and vegetables thrive here (herbs, tomatoes, peppers, and lettuce). This is in part due to the number of pollinators that green roofs bring to the area, but also because these are ideal plant as their roots are not very deep. Not only do green roofs provide food, but they provide aesthetic appeal, something that can be lost in a sea of steel.
So, next time you see some green flowing from the top or side of a building, instead of questioning it, think of all of the benefits they are providing for you and other residents of the city. This may be the future of all cities if landscape architects, and urban planners continue to find the plentiful benefits for a city.