Mitigating New York City’s heat island with urban forestry, living roofs, and light surfaces. New York City regional heat island initiative final report

New York City’s urban heat island averages ~7°F on summer nights and can be particularly pronounced during heat waves. For this study, a regional climate model (MM5) was used in combination with weather, satellite, and GIS data to compare nine scenarios involving combinations of urban forestry, green roofs, and lighter surfaces (increased albedo) to reduce the urban heat island effect. Each scenario was assessed for its effect on temperature, impact on energy use, and cost-effectiveness. The most effective strategy involved maximizing the amount of vegetation through tree plantings along streets and in open spaces and by planting living roofs. Curbside plantings were the most effective on a per-unit area basis.