From local climate zones to neighborhood green-cover gaps: A UHI-informed green-cover benchmark for Copenhagen

Source abstract

As global warming increases heat extremes, urban greening is becoming increasingly important, particularly where the canopy-layer urban heat island (CUHI) intensifies nighttime heat exposure. However, neighborhood-scale green-cover targets are rarely grounded in locally observed air-temperature differences. This study develops an empirical green-cover benchmark for Copenhagen and applies it to assess neighborhood-scale gaps. The relationship between green cover and nighttime air temperature during warm waves was examined across nine Local Climate Zone (LCZ) classes representing an urban-to-natural gradient. Air-temperature observations were obtained from privately owned weather stations across the Capital Region of Denmark, while green-cover shares were derived from a 20 cm resolution land-cover map. Among the built classes, LCZ 9, representing a sparsely built form, had the lowest mean air nighttime temperatures. Its land-cover characteristics were used to derive a 60% green-cover benchmark. Application to Copenhagen’s 11 administrative neighborhoods identified the largest gaps in Inner City, Norrebro, and Osterbro, with green coverages of only 18-21%. Vesterbro, Amager Ost, and Frederiksberg reached half of the benchmark with coverages of 27-31%, while Bronshoj and Amager Vest had the smallest gaps with coverages of 49% and 56%, respectively. The benchmark provides a locally grounded reference for identifying where greening may be most relevant from a CUHI perspective.