Green Roofs - Nature in the City

Have you ever been introduced to something you had never known before only to have it pop up over and over again while going about your everyday routine? Like a word you had never known or a song you had never heard becomes known to you and then you read the word in the next morning's paper or hear the song during your favorite TV show. It seems like such a strange coincidence, like the universe wanted you to specifically know that tiny tidbit of information.

That happened to me this week while reading for class. Spirn's (1984) view of the city as part of nature could not be more readily captured in the devastating floods unfolding before my eyes in my homestate of Colorado. The idea of city as part of nature was illuminated in my mind the day after I read the passage. I watched the roads I rode to work on everyday eroded away by a 500-year flooding event, I connected what was happening in the real world to Spirn's words on the page. What came to mind specifically was a quote in the chapter: "nature in the city....is the consequence of a complex interaction between the multiple purposes and activities of human beings...and of natural processes that govern the transfer of energy, the movement of air, the erosion of the earth, and the hydrologic cycle. The city is part of nature." But how do we live comfortably and securely with nature?

In understanding that the urban environment is part of a larger, natural system, it would seem to me that this leads to an adaptation in behavior to better co-exist in nature. There are many environmental processes (fire, flood, drought, extreme temperature variation, etc.) that affect the decisions we make regarding how we go about our daily business and build the infrastructure for those tasks. For many years, we sprawled out in all directions, uprooting soil-conserving trees and paving over permeable surfaces. As Spirn mentions, and I whole-heartedly agree, there is a danger in not recognizing the impact nature has on the urban environment and choosing to not plan ahead for these events. However, we have come far enough in technological terms to begin to address our place in the larger context of nature and make adjustments to our way of life. To keep the scope of these adjustments somewhat refined, I considered the impact of what is most recently on my mind, urban stormwater runoff. Within the methods recognized as assisting to mitigate the runoff, I chose to look at green roofs and the process of implementing such a project in the urban environment.

Apartment building green roof in Portland, Oregon

(Photo courtesy of the Portland Bureau of Environmental Services, via the Environmental Protection Agency)

 

Green roofs, as defined by the Environmental Protection Agency (2013), are a vegetative layer grown on a rooftop and are commonly espoused as an alternative roofing material with a multitude of benefits to the environment and the building. Benefits include:

Reduced energy use: Green roofs absorb heat and act as insulators for buildings, reducing energy needed to provide cooling and heating.

Reduced air pollution and greenhouse gas emissions: By lowering air conditioning demand, green roofs can decrease the production of associated air pollution and greenhouse gas emissions. Vegetation can also remove air pollutants and greenhouse gas emissions through dry deposition and carbon sequestration and storage.

Improved human health and comfort: Green roofs, by reducing heat transfer through the building roof, can improve indoor comfort and lower heat stress associated with heat waves.

Enhanced stormwater management and water quality: Green roofs can reduce and slow stormwater runoff in the urban environment; they also filter pollutants from rainfall.

Improved quality of life: Green roofs can provide aesthetic value and habitat for many species.

(Environmental Protection Agency, 2013)

While the benefits of green roofs seem enticing and like a step in a positive direction, when considering such an intensive endeavor, I begin to think about what must be considered and how it should be presented to achieve buy-in with the larger population. To simplify the process, I chose to analyze an existing green roof building guide, the District of Columbia's District Department of the Environment Green Roof Toolkit, through the lens of Mckenzie-Mohr's Fostering Sustainable Behavior: Community Based Social Marketing (CBSM). In the book, Mckenzie-Mohr identifies seven categories that should be addressed when marketing your sustainable cause or agenda to a broad audience: commitment, social norms, social diffusion, prompts, communication, incentives, convenience. Below are my recommendations or interprestations of what has already been done in the District of Columbia to address these categories.

Commitment
Though this program is not directly asking for commitment from the citizens of the District of Columbia (D.C.), I do not see why it has to be that way. In accordance with the recommendations of Mckenzie-Mohr, could call residents and business owners inquiring about their interest in building a green roof on their residence or building. If interest is high, they could start with a request of a verbal commitment to the project with small crews of empolyees following up with comitted parties to have a signed commitment on file. Additionally, the commitments can be documented publicly in a local newspaper or television news story to enhance the profile of the project and provide enhanced motivation for the parties involved to stick with their commitment.

Social Norms
To make the norm of creating a green roof noticable, as Mckenzie-Mohr suggests, photos of locally completed projects and anecdotes from the players involved about the impact of the green roof to their lives could serve to normalize the project. By focusing on successful green roof projects, and not the traditionally-roofed buildings taht we would like to be converted to green roofs, we are utilizing the injunctive behavior as our example; what we as a community approve of for the greater good of the environment and our community.

Social Diffusion 
This part of the plan ties in well with the first two categories in that if you are asking someone to commit to such a large project, and they accept, they are more likely than not to share those experiences. The D.C. could gain a commitment from those who are willing to build green roofs to share anecdotes with others in their local and professional community about why they chose to make the switch and what has resulted. This can be funnelled into materials used to attract more individuals targeted by the DDOE to build green roofs.

Prompts
Some categories suggested by Mckenzie-Mohr are not always suitable for the project at hand or the behavior one is trying to influence. As mentioned in the CBSM, prompts may be most suitable for "establishing and maintaining repetitive behaviors that favor sustainability" and building a green roof does not fall under that category. None the less, this is an important characteristic of the project to recognize as each category may not always be appropriate for the goals of each sustainability project.

Communication
The Green Roof Toolkit offers extensve information regarding the benefits and barriers to creating a green roof, but this information can be whittled down to be most impactful on the customer in a short period of time. The given example in the CBSM regarding vivid explanation of current conditions to get the individual to look at the situation differently can certainly be used in the same way for green roof building. One could explain to homeowners how much stormwater runoff they are saving in terms of how many pools or bathtubs said runoff could fill. The amount of roof material waste diverted from the landfill could be described in terms of how deep  it would cover their yard if laid out.

Incentives
The DDOE offered a $7 per square foot subsidy for businesses and homeowners interested in pursuing this process. This is not covered in the Green Roof Toolkit but the cost of building a green roof is included. The subsidy could easily be added to the toolkit and a table could be created to demonstrate the cost savings by taking advantage of the subsidy.

Convenience
Convenience is not a focus of this project as it is very labor and time intensive and requires a fair amount of upkeep. That can be presented up front, and it is presented in the toolkit, however, I posit the idea of pairing a representative of the DDOE with individuals or businesses taking on a green roof project as a liaison who can answer questions and help walk through the process from start to finish. This could help to diminish the learning curve for such an intense project and while empowering the party taking on the project to find answers to their questions and educating them at the same time.

 

References



 



Spirn, A.W. (1984). City and nature from the granite garden: urban nature and human design. In S.M. Wheeler & T. Beatley (Eds.), The sustainable urban development reader. (2nd ed.; pp.139-144). New York, NY: Routledge.

Environmental Protection Agency. (2013). Heat island mitigation: green roofs. Retrieved from http://www.epa.gov/hiri/mitigation/greenroofs.htm

District Department of the Environment. (2012). Green roof toolkit. Retrieved from http://budget.dc.gov/sites/default/files/dc/sites/ddoe/publication/attachments/GR%20Toolkit%2012.22.11.pdf.

Mckenzie-Mohr, D. (2006). Fostering sustainable behavior: community based social marketing. Retrieved from http://www.cbsm.com/pages/guide/preface