Balancing cooling benefits and costs: Determining a moderate park scale in 24 Chinese cities

Abstract

Urban parks present an effective solution to mitigate urban heat, but their implementation can be costly. Thus, determining a moderate park scale is essential to balance cooling benefits and associated costs. However, the magnitude of park cooling benefits and their associated costs remain poorly understood. This study analyzed park cooling benefits and costs using high-resolution satellite data on land surface temperatures for 3258 urban parks in 24 Chinese cities. A novel method was developed to determine the moderate park scale for these cities. The study revealed that urban parks in 24 Chinese cities, on average, lower temperatures by 1.48 °C and extend this cooling effect over an average distance of 183 m. The cooled areas of urban parks account for 5.67 % of the total built-up area and benefit 18.13 % of urban residents. The total cooling benefit is estimated at 1.73 billion yuan, mainly due to the extended cooling effect. Park cooling costs are estimated at 0.83 billion yuan, resulting in net cooling benefits of 0.9 billion yuan across these cities. Beijing exhibited the highest park cooling benefits but also the highest cooling costs. The study identified a moderate scale range of 3.2–8.3 ha, which could enhance total and net cooling benefits by 25–50 % across these cities. Notably, in water scarce megacities like Beijing and Tianjin, smaller parks (3–4 ha) may yield the highest net cooling benefits.