By now we’ve heard of the circular economy, a process for making the world more sustainable, creating a cycle that reuses and captures resources. Now, circular economies are turning to urban planning to make our cities into circular cities. Right now, more than half of the population lives in a city, and by 2050 that will rise to two thirds. If we’re going to continue to build up and out, we need to figure out how to better use resources.
One major source of greening a city is by covering buildings in plants. We’ve all seen grass-covered rooves and even plant-covered walls, but the most sustainable cities show that using greenery not only provides an aesthetic affect to our buildings, but an insulative one as well. Green buildings manage storm water, heat stress, air quality and biodiversity.
In addition to providing insulation, green roofs can double the life of flat roof through reduced weather stress, as shown in cities like Berlin, where they have been covering buildings in plants for more than a hundred years to amazing results.
A second major benefit of creating a circular city is managing storm water, both in using it to feed the green roofs, but also capturing it for reclamation and reuse for both potable and non-potable applications. In New York, Brooklyn is creating a “sponge park” to help clean a long polluted canal. China is launching a sponge initiative for the purpose of putting less strain on waning water supplies and wastewater treatment plants.
In Berlin, 30,000 square meters of Potsdamer Platz is facilitated to reclaim water to be used for irrigation and flushing toilets. Toronto has even gone so far as to make green roofs obligatory since 2009.
A third major benefit is the energy reduction of circular cities. A recent study in the European Union showed that 40% of their energy was lost through the heating and cooling of buildings, and 1/3 of greenhouse gasses came from this power output. By insulating buildings with greenery, this is not only mitigated, but other the plants take an active part in reducing carbon dioxide, nitrous oxide and sulfur oxide, and particulate matter.
And best of all, green buildings of circular cities are more appealing both aesthetically and economically. A building with a green roof has a better resale value than a concrete roof, and is more welcoming to inhabitants. The greenery even affects temperatures outside of buildings: Potsdamer Platz is shown to be 2 degrees C less in the summer months than the surrounding areas.
To learn more about circular cities, visit Fast Company.