Baseline Analysis of Green Roof Distribution in New York City Published in Peer-Reviewed Journal, Ecology & Society

The Nature Conservancy is pleased to announce the publication of Examining the Distribution of Green Roofs in New York City Through a Lens of Social, Ecological, and Technological Filters in the peer-reviewed journal Ecology and Society. Co-authored with researchers from The New School, the Wildlife Conservation Society and Columbia University, the paper describes the development of a publicly-available dataset on green roofs in New York City, along with insights into potential drivers of where they are and what the distribution might mean for the benefits they can offer. Put into context with existing city data such as on heat vulnerability and combined sewer overflows, this dataset can inform green roof planning and policy in New York City.

Green roofs are a nature-based solution that can help the city adapt to a changing climate with increasing temperatures and more frequent and intense rainfall. Yet the research finds that as of 2016, green roofs were rare in New York City, found on less than 0.1% of buildings – mostly in midtown and downtown Manhattan, with few to none in most other areas of the city.

Dr. Mike Treglia, Lead Scientist for The Nature Conservancy’s Cities Team in New York said, “This effort established the first dataset of green roofs in New York City, which is a critical step for being able to understand where their benefits are being offered and for tracking changes through time. This information, as well as insights on the types of buildings we see green roofs on, such as public vs. private, is ultimately invaluable in working with policymakers, advocates and researchers to expand green roofs, particularly in areas where they are most needed.” 

“If we are going to meet our goals for climate adaptation, sustainability and equity, we have to invest more in our green roofs alongside other green spaces.” said Dr. Timon McPhearson, Director of the Urban Systems Lab at The New School. “The unmet opportunity to transform the flat roof space in New York City is vast. Mobilizing city resources to expand green roofs especially in underserved neighborhoods could go a long way towards cooling the city, improving stormwater resiliency and providing new recreation spaces.”

“New York City's roofs were once upon a time all green, composed of a near-continuous forest canopy that ran from river to sea across the city's archipelago.” said Dr. Eric W. Sanderson, Senior Conservation Ecologist, Wildlife Conservation Society. “Although this paper shows we are far from the cooling, water-absorbing, biodiversity-full, leafy embrace of the past, understanding where we are and what we can do next is necessary to grow a greener and more resilient future.”

“We pursued this research because rooftops in New York City, comprised of about 40,000 acres spread over one million buildings, present a tremendous opportunity.” said Emily Nobel Maxwell, Director of The Nature Conservancy’s Cities Team in New York. “What is on the surface of this vast expanse significantly affects our city and all those who live, work and visit here. It can either mitigate or exacerbate the urban heat island effect and local flooding. Before this research, there was not a clear picture of the extent of green roofs in New York City. Now, we can advance better use of this underutilized form of green infrastructure and do so in a way that advances equity and justice.”

Various types of policies can support increased green roof installations. As New York City implements local laws 92 and 94 of 2019 and offers incentives such as a property tax abatement that can support installation of more green roofs, data on their distribution are key to informing future efforts. 

The Nature Conservancy collaborated with fellow members of the New York City Green Roof Researchers Alliance, convened by NYC Audubon, to develop the dataset and write the paper. The dataset is publicly available and the methods used to develop it, documented in the paper, can be transferred to various other cities, nationally and internationally, to establish similar understanding of green roofs elsewhere. An updated dataset of green roofs in New York City is currently in development by The Nature Conservancy. When available, it will allow for an understanding of how the distribution of green roofs in New York City has changed since 2016.

The Urban Systems Lab (USL) at The New School is an interdisciplinary research, design, and practice space at The New School that provides knowledge and analysis for developing more equitable, resilient, and sustainable cities. The USL's work advances cutting-edge science, data visualization and computation to develop systemic solutions to social and environmental challenges driving inequity and injustice in urban areas. We bring together designers, urban ecologists, scientists, researchers and policymakers with the goal of improving the lives of the most vulnerable people and improving decision making and science communication at scales ranging from the local to the global.

To learn more, visit www.newschool.edu or follow @thenewschool on Twitter.

Wildlife Conservation Society (WCS) saves wildlife and wild places worldwide through science, conservation action, education and inspiring people to value nature. To achieve our mission, WCS, based at the Bronx Zoo, harnesses the power of its Global Conservation Program in nearly 60 nations and in all the world’s oceans and its five wildlife parks in New York City, visited by 4 million people annually. WCS combines its expertise in the field, zoos and aquarium to achieve its conservation mission.

To learn more, visit newsroom.wcs.org or follow @WCSNewsroom on twitter.

The Center for International Earth Science Information Network (CIESIN) is a transdisciplinary research and data center of the Columbia Climate School that develops, hosts and distributes data on human interactions with the environment, environmental change and social impacts. We also produce mapping tools and services to integrate and visualize data in new ways to enhance possibilities for understanding and contribute to new applications—by the research community, policymakers and the general public.

To learn more, visit www.climate.columbia.edu or follow @colombiaclimate on Twitter.