Open Access

Nathalie Burdová

• With the increasing threats of climate change and the associated rise in climate extremes and natural hazards, there has been a growing focus on studies addressing mitigation and adaptation strategies for these hazards, one of which is urban heat islands (UHI). The strategies for mitigating UHI are well-established, with urban green infrastructure being one of the most effective approaches. Previous research has shown that green infrastructure can significantly reduce urban temperatures, although its effectiveness varies depending on specific properties. The cooling effectiveness of these infrastructures differs based on various factors.This paper investigates the cooling potential of various types of green infrastructure, including trees, green roofs, and vertical greenery, in a 16-ha area in Cologne's Volksgarten quarter, based on their biophysical properties. The primary objective was to develop a criteria set for green infrastructure characteristics that enhance cooling potential and climate resilience and to apply this set in assessing the area’s cooling potential. A mixed-methods approach was employed, incorporating literature analysis to define the criteria sets, alongside spatial analysis, in-situ observations, and transpiration modelling to evaluate the study area’s actual cooling potential. The results indicated that, particularly for trees, shading properties based on ecological characteristics such as LAI, height, and crown width play a significant role. For green roofs and vertical greenery, system type characteristics and orientation are potentially more influential. The analysis also included the number of existing infrastructures and based on evaluations of these groups and their locations within the study area, it was possible to identify so-called “cool” and “hot spots” in the study area. The study concludes that while current green infrastructure implementations in the study area have medium cooling potential, there are also clear opportunities for improvement. From these findings, a targeted set of recommendations was drafted to not only enhance cooling potential and climate resistance but also to incorporate additional co-benefits, where specifically for trees, it was possible to make such recommendations even on the species level. This study offers a novel approach to evaluating mitigation strategies, contributing to a deeper understanding of the role of green infrastructure in urban climate resilience, and providing an approach to optimising its benefits with potential implications for urban planners.