Cooling Detroit: A socio-spatial analysis of equity in green roofs as an urban heat island mitigation strategy

Abstract

Multiple studies have quantified the ecosystem services of green infrastructure for both public and environmental health. This study evaluates and compares accessibility of low-income and marginalized communities to the cooling benefits of green roofs in Detroit, MI in the context of the urban heat island effect and the City’s current heat relief system of dedicated cooling centers. Regions of the city were evaluated for their vulnerability to the urban heat island effect, which can be alleviated by green roofs due to raised surface albedo and evaporative cooling. Spatial data regarding land surface temperature, income, and race were used to locate where green roof ecosystem services are most needed and how communities within these regions are categorized demographically. Existing green roof efforts were mapped to determine whether siting has occurred where ecosystem services are most needed and how socioeconomic factors might be related to the locations of urban heat island-mitigating green infrastructure. Analysis of the spatial data in this study revealed most low-income residents are within walking distance from cooling centers, but not included in the Detroit Future City Urban Green Neighborhoods, while green roofs specifically were in the affluent part of Detroit's urban core, where the population is predominantly white. The methodology employed here can be applied to evaluate urban greening plans in other cities.