“Green Roof Policy, Incentives, Management, and Education” Recap
I recently attended the NYC Green Roof Researchers Alliance’s first conference on “The State of Green Roofs in NYC.”
Here’s a summary of some of the key takeaways from a session on “Green Roof Policy, Incentives, Management, and Education.”
Speakers
(1) Niki Jackson – NYC Audubon | “Kingsland Wildflowers: A case study of community outreach and education.”
(2) Toby Sheppard Bloch – The HOPE Program | “Bringing Environmental Justice Full Circle: Addressing the public health effects of climate change by greening the built environment.”
(3) Vicki Sando – P.S. 41 | “Educational Green Roofs.”
(4) Jason Aloisio – The Wildlife Conservation Society | “Green Roofs as Tools for Research, Education, and More.”
(5) Susan Elbin & Rebecca Marshall – NYC Audubon and The Jacob K. Javits Center | “We Have a Plan: A Conservation Management Plan Approach for Multi-Use Green Roof Activities.”
(6) Chris Ziemba – Fordham University | “An Analysis of Green Roof Incentive Programs in Cities in the USA.”
Benefits of Green Roofs
A few years ago, I encountered green roofs while traveling abroad and wrote about what they are and some of their basic benefits. In NYC, buildings are responsible for 73% of greenhouse gases (2); green roofs can help reduce that impact while also providing additional benefits for the triple bottom line. Here are a few that were covered during the conference:
Economic Benefits
- Employment: Green roofs can help with environmental justice efforts by “bridging the gap” between making communities more livable and more economically robust. Through efforts like the HOPE program, they can help spur job creation, especially in entry level positions (2).
- Cost Reduction: Green roofs can help decrease heating and cooling costs; for instance, P.S. 41 saw a 20% reduction in energy use (3). In addition, they can help a roof last longer. At the Javits Center, there were leaks in the original roof; retrofitting it with a green roof helped with waterproofing (5).
Social Benefits
- Educational green space: NYC are often “starved” for green space. Green roofs can help “reconnect kids with nature” by providing additional year-round outdoor space. In addition to providing educational opportunities for architecture, engineering, and other fields that are typically associated with green roofs, teachers can use the space for many different kinds of activities, including art and movement classes. Vicki recommended providing teachers with ways to incorporate the green roof into their pre-existing curricula.
- Research: The green roof could also be used as a research lab, especially if students’ access to it was controlled (3). Jason provided some examples of how high school and college students could use a green roof together for research. Undergraduate students mentored high school students as they ran studies on the Bronx Zoo’s green roof, which was originally planted with native vegetation in 2009. Over the years, it was not maintained, and it seemed as though there were not many natives left.
- Students studied how the species composition had changed over time and discovered that only 6 natives were still present, with only half of them having more than 1% cover; meanwhile, there were over 20 colonist species. In addition, because it was a sloped roof, certain plant types grew closer to the bottom and others were closer to the top. Students provided recommendations on green roof management based on their findings, which were later applied (4).
- Public Outreach: Green roofs were used for workshops, tours, and volunteer opportunities for planting and weeding, according to Niki (1). They can help create a better public image, especially for clients who are looking to host events in a “sustainable building” (5). They have even provided herbs for local soup kitchens (3).
Environmental Benefits
- Climate change adaptation and resilliency: Green roofs can help reduce combined sewer overflow by retaining stormwater (5). In addition, they can help counter the urban heat island effect; while traditional roofs can be up to 70º hotter than the ambient temperature, green roof temperatures can actually be lower than the surrounding area (2).
- Climate change mitigation: Green roofs can function as a carbon sink (5). In addition, they can help reduce electricity demand; for instance, P.S. 41 saw a 20% reduction in energy use and greenhouse gas emissions (3).
- Air quality: For instance, “1000 square feet of green roofing can remove the equivalent of 15 cars’ worth of particulate matter” (2).
- Biodiversity: Depending on the plants used to create green roofs, they can increase the presence of native plants in the landscape and provide habitat for a variety of pollinators (3).
Challenges and Considerations
- Need for a critical mass: There need to be enough green roofs concentrated in a downtown area to get the greatest reduction possible in combined sewer overflow and the heat island effect (6).
- Time: In addition, some of the benefits are best seen over a long term. It can also take time to get a green roof established. Vicki Sando recounted how she started with a school garden for a few years before she had to stop adding more plants to it, so she decided to try a roof garden. She worked with the School Construction Authority (SCA), and it ended up taking 4 years of planning and 2 years of construction.
- Ongoing maintenance and support: Green roofs may require different kinds of maintenance depending on how they are set up. There are companies which can assist with maintenance; for instance, at P.S. 41, they contract with a green roof company and run fundraising events to cover maintenance. They also have a dedicated coalition that can help cover any additional costs and ensure that the green roof has ongoing support. Since it can be a long process, it’s best to start small–like with a school garden–to make sure that there is adequate enthusiasm for the project before investing time and money into it (3).
- Unknowns: I caught a bit of the end of the previous session, where the concluding remarks stated that some questions about green roofs are difficult to answer because every green roof is a different “complicated ecosystem.” In addition, they are living systems that can change over time, which can create challenges when it comes to managing building owner expectations. For example, one green roof started to have clover growth, which was considered unsightly. However, it turned out that honeybees had started pollinating the flowers. After dialogue with the building owner, it was agreed that the patch of clover could be left alone (2).
- Sharing space: In some cases, roof space needs to be shared with other features like solar panels (2). In addition, a flexible plan may be needed to coordinate between different entities that use the roof, ranging from nesting birds to tour groups. If multiple groups are sharing a green roof, protocols may be necessary to determine if or when data is shared, when access is granted to the roof, etc. (5).
Efforts to Promote Green Roofs
Because many of the benefits of green roofs are most directly felt by the surrounding community and environment, building developers are the least likely to see an immediate ROI, even though they’re often the ones to invest in green roofs (6). In addition, although green infrastructure is increasingly being included in design plans, green roofs adoption rates have fluctuated over the past few years (2).
To ensure that the benefits outweigh the costs for building owners, cities are experimenting with a variety of tools, including grants, tax abatements, technical assistance, integration with LEED, stormwater utility fees, and more (6).
Chicago has so far been the most successful in the United States in encouraging adoption of green roofs. Buildings receiving public funding must include green roofs, and the process for adding a green roof is now faster and cheaper. A mapping tool highlights locally installed green roofs.
In NYC, the DEP is providing funding for installing green infrastructure on private property in an effort to “absorb 1 inch of rainfall on 10% of the city’s impervious surface area” (2). There was also a tax abatement available, although only a handful of property owners applied. More research is needed to determine which of these tools will be the most successful in encouraging installation of green roofs (6).
Additional Resources
NWF Eco Schools Green Roof Curriculum Guide [In Progress]
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