Examining the distribution of green roofs in New York City through a lens of social, ecological, and technological filters

Abstract

Green roofs provide multiple benefits including reducing the urban heat island effect, absorbing stormwater and air pollution, and serving as habitat for wildlife. However, many cities have not taken advantage of green roofs as a nature-based solution.In New York City (NYC), approximately 20% of the landscape is covered by buildings, thus rooftops present a substantial opportunity for expanding green infrastructure. Spatial data on green roofs are critical for understanding their abundance and distribution, what filters may drive spatial patterns, and who benefits from them. We describe the development of a green roof dataset for NYC based on publicly available data and classification of aerial imagery from 2016. Of the over one million buildings in NYC, we found only 736 with green roofs (<0.1%), although there may have been others we did not detect. These green roofs are not evenly distributed in NYC -they are most common in midtown and downtown Manhattan, while most other areas have few to none. Green roofs tend to be more prevalent in parts of NYC with combined sewer systems, but some such areas, and those with the most heat-vulnerable communities, have few if any despite their potential to help ameliorate stormwater and urban heat challenges. Though green roofs are providing some benefits within NYC, we anticipate they are filtered based on dynamics of infrastructure, institutions, and perceptions, rather than targeted to address climate and weather-related challenges. There is substantial opportunity in NYC to increase green roofs, and equity of them. The dataset we developed is publicly available and can serve as a baseline for tracking these assets through time, while supporting further research, conversations, and policies related to the benefits and distribution of green roofs. The underlying methods can also be applied to help fill similar data gaps in other cities.

Adapting Street Profile Design by Using Nature-Based Solutions in New Neighbourhoods and the Retrofit of Buildings

“…Visual impact NbSs such as green roofs and green walls have become popular architectural design instruments and criteria for residential and governmental buildings have been developed [46]. Green roofs, in which geo-cells can be used aside geotextiles, not only contribute to decreased UHI effects, but also contribute to urban flood mitigation as a result of rainwater retention [47], and have the potential of being private interconnectors between larger forms of urban (and public) green infrastructure [48]. This role is also taken on by the vertical layer in green walls, which can link street vegetation and biodiversity, via facade-greening strata, to the green roofs of the same or adjoining building [49], which was also exemplified in the Vienna case study and in the 3D study of a proposed development in Măgurele, a Bucharest suburban research area.…”

De-Sealing Reverses Habitat Decay More Than Increasing Groundcover Vegetation

“…We designed green roofs for buildings on campus that have sufficiently large areas of open, flat roof to absorb more stormwater on-site and restore some of the biodiversity that was lost during the construction of the campus [74,75]. These green roofs would have a thick layer of soil to reduce the heat-island effect, and they would be planted with lowgrowth, drought-tolerant, indigenous species, such as oregano, juniper, lavender, thyme, and various succulents.…”

Based on nature, enabled by social-ecological-technological context: deriving benefit from urban green and blue infrastructure

“…Grounded in this more comprehensive understanding of individuals' decisions in terms of accessing and realizing recreational benefits, the authors propose three complementary pathways for improving access to the recreational benefits of urban GBI: programming the environment, building knowledge, and supporting engagement. Treglia et al (2022) discuss green roofs as a strategy for converting often un-and underutilized and potentially problematic spaces into multifunctional parts of the landscape, using five boroughs of New York City, USA, as an example. The study demonstrates an implicit injustice: outside midtown and downtown Manhattan, most of the city districts, including areas that face stormwater management challenges and communities that are most vulnerable to impacts of heat waves, are comparatively underserved.…”