By Marilyn Novy for SUST 210*
In the past decade, there has been a push to make our cities more sustainable. A noticeable change that has been occurring is the addition of many green roofs throughout cities. As of now, Chicago is one of the leading cities with green infrastructure. Chicago currently has almost 500 green roofs totaling to 5.5 million square feet. Chicago started its green roof programs in 2001; the previous Mayor of Chicago, Richard Daley, had a 20,000- square-foot green roof installed on City Hall, creating a high-profile example of the city’s commitment to energy conservation and green design.
Green roofs bring many benefits and have few disadvantages. Green roofs are installed for many beneficial reasons: they diminish the heat island effect, provide insulation resulting in a reduced need for air conditioning, absorb rainwater, lower the amount of stormwater runoff, and create habitat for wildlife. Naturally, everything has its drawbacks, but fortunately, the only true disadvantage a green roof has is the initial costs of the waterproofing system and root barriers which need to be installed. These costs do, however, eventually pay themselves off because of the savings from reduced air conditioning use.
In an article “Growing Green Roofs, City by City,” author David Taylor discusses how Chicago officials have noticed that green roofs are not only helpful for moderating the blast of runoff from rainstorms, but are also beneficial for moderating the city’s “heat island effect.” The reason for wanting to decrease the difference of temperature is because heat islands raise energy demands and air pollution levels, and they are causes of heat-related illnesses. The city’s environmental commissioner at the time, Sadhu Johnston, explains in this article that green roofs can aid in averting heat wave-related deaths, noting that studies show green roofs have lower temperatures than traditional roofs and, in return, reduce the need for air-conditioning.
Chicago now requires all new city buildings to have at least a partial green roof in order to achieve a silver LEED certification. Most of the green roofs have been installed under regulations and the city has required every developer who is receiving city assistance to include either a cool roof or vegetated roof. With all of these green roofs being installed, Chicago has seen its cost of installation go down.
Submitted 19 Apr 2013
* Each week during the Spring 2013 semester, two to three students in the SUST 210 Sustainable Future online/Schaumburg class at Roosevelt University will contribute blog posts to the Schaumburg’s Sustainable Future website.