To: Professor MacBride
From: Jessica Lin
Date: April 15, 2013
Re: Annotated Bibliography – The Reality of Green Roofs
1. Urban Design Lab at the Earth Institute, and Columbia University. “The Potential for Urban Agriculture.” The Potential for Urban Agriculture in New York City, 2012. http://webcache.googleusercontent.com/search?q=cache:Or-Ys3luNV0J:www.urbandesignlab.columbia.edu/sitefiles/file/urban_agriculture_nyc.pdf+history+of+development+of+rooftop+farming&cd=9&hl=en&ct=clnk&gl=us.
Summary: “The Potential for Urban Agriculture” focuses on all types of urban agriculture, including community gardens, open space farming, rooftop farming, etc. This study gives information on all aspects of urban agriculture: The planning stage – what needs to be considered, the costs and benefits, and so forth; The potential of urban agriculture – what spaces and how much space is available and can be used in every borough of New York City; The issues NYC faces and how urban agriculture can help – obesity correlated to the lack of fresh foods, storm water run-off, the urban heat island effect, and waste composting; Incentives for urban agriculture, including tax abatements for green roofs.
Rationale: This article is particularly relevant because it contains a vast amount of information about the potential and the difficulties of urban agriculture specifically in New York City. I would like to use on the information it provides on green roofs. To know how realistic green roofs are, it is good to have number or percentage in mind of how many roofs can actually be used. This is provided in the study. For my paper, I am bringing to focus two issues that rooftop farming tackles: storm water run-off and the urban heat island effect, because these two issues are relevant to New York City. This study also provides a useful amount of statistics and information on the two issues. It shows that green roofs can help to reduce the temperature of New York City provided by a study done by NASA, and that there has already been incentives taken towards green roofs that help to combat water run off.
2. Rosenberg, Tina. 2012. “Green Roofs in Big Cities Bring Relief From Above.” The Opinionator. http://opinionator.blogs.nytimes.com/2012/05/23/in-urban-jungles-green-roofs-bring-relief-from-above/
Summary: Big cities have to face the issues of water run-off and the urban heat island effect. This blog explains the types of green roofs there are, intensive and extensive roofs. Of course installing green roofs are not simple or cheap, but there are shown benefits. Studies have been done to provide statistics and results of green roofs compared to our traditional black roofs. There are many places that have already begun various types of green roofs.
Rationale: This blog is very important because it provides the general overview of green roofs. It also provides valuable resources and summarizes them, Leading me to two green roof studies done in New York City which I will provide in the next two citations. As well, according to Amy Norquist, green roofs also tackle climate change through absorption of carbon emissions. One square meter of green roof can absorb the emissions of one car driven 12,000 miles a year. This is another potential of green roofs.
3. S.R. Gaffin, C. Rosenzweig, J. Eichenbaum-Pikser, R. Khanbilvardi, T. Susca. “A Temperature and Seasonal Energy Analysis of Green, White, and Black Roofs” Columbia University, Center for Climate Systems Research. New York.
Summary: In this report, Columbia uses Con Edisons “Learning Center” Roof Project of green, black, and white roofs to create an analysis of how heat flow varies from black roofs, white reflective roofs, and green living roofs. These roofs are located in Queens. In summary, black roofs absorb the most amount of heat. White roofs are cooler than black roofs, and green roofs are cooler than white roofs. During winter time, black roofs showed the highest temperature heat loss, while green roofs had a lower heat loss rate. It is important to note that this report provides statistics of heat and temperature pertaining to buildings in New York City, and not the temperature or heat of New York City in general.
Rationale: While statistics may show that green roofs can help to reduce New York City temperature by several degrees, to us that may not sound to be a lot. This report by Columbia focuses on the temperature effects on buildings. This directly effects us because we are the residents of these buildings. The statistics provided by the report help to show just how much a building we live in (just like the roofs in the report, located right here in Queens, New York) can be cooler in the summer, warmer in the winter, and indication of energy conservation due to these effects. Also, the reduction of heat due to green roofs is thought to have correlating effects on energy conservation. However, as stated in this report, it is shown that energy savings are modest. This shows that there is a reduction, but it may not be much.
4. Gaffin, S. R., Rosenzweig, C., Khanbilvardi, R., Eichenbaum-Pikser, J., Hillel, D., Culligan, P., McGillis, W., and Odlin, M., 2011. “Stormwater Retention for a Modular Green Roof Using Energy Balance Data“ Columbia University, Center for Climate Systems Research. New York. 19 pages
Summary: Using the Con Edison Learning Center, statistics were collected and analyzed between a green roof, white roof, and black roof. Black roofs show the highest absorption of heat, white roofs reflect and retain less heat than black roofs, and green roofs retain the least amount of heat compared to the other two. It can be concluded from this study that green roofs are most effective in all aspects concerning building temperature.
Rationale: To understand the potential and benefits of green roofs in combatting storm water run off, we need to know just how much water can be retained by these roofs and how it works? This study, which also used the Con Edison Learning Center, shows just how much water can be retained annually and throughout the summer by this building. The evaporation of water from a green roof is equivalent to the amount of water that is retained by a green roof and never enters the sewage system. This study is significant because we can then use these statistics to estimate how much water can be kept of the water system if we implemented green roofs on a larger scale. This helps to prove that green roofs are an effective solution.
5. EPA. 2008. “Green Roofs” Reducing Urban Heat Islands: Compendium of Strategies. Environmental Protection Agency. http://www.epa.gov/heatisld/resources/pdf/GreenRoofsCompendium.pdf
Summary: This chapter explores the urban heat island effect through green roofs. It explains the two types of green roofs: intensive and extensive, and goes into an analysis of the costs and benefits of installing green roofs. Green roofs work through shading and evapotranspiration. There are also other factors that must be considered. Several case studies of green roof initiatives are included. The research used to support this chapter is taken from other states and even in places like Canada.
Rationale: Before we focus on the benefits of green roofs we first need to understand how green roofs work, and the types of green roofs there are. This gives a thorough understanding of green roofs and more support of how green roofs reduce energy, collect water, but more importantly this is one of the sources that provides more information on how it reduces greenhouse gases through absorption. It also provides links to research being conducted by university programs which is very useful.