The Cooling Effect and Its Stability in Urban Green Space in the Context of Global Warming: A Case Study of Changchun, China

The urban heat island effect, triggered by global warming and rapid urbanization, has negatively impacted residents' lives. It has been shown that urban green space (UGS) can improve the urban thermal environment. However, the stability and influencing factors of the urban green space cooling effect (UGSCE) in the context of climate change remain unclear. In this paper, we study the area within the Fifth Ring Road of Changchun City, using multi-source remote sensing image data to quantify and analyze the influencing factors of the cooling effect of urban green space and its stability on both regional and patch scales. The results show that on the regional scale, urban green spaces in Changchun have a strong cooling effect on the surrounding environment, which increases with the surface temperature (LST). However, there is a large fluctuation in the cooling effect. On the patch scale, the cooling effect of 35 green spaces showed a small increasing trend from 2013 to 2024. The cooling extent (CE) was more stable across temperatures relative to the cooling intensity (CI). Factors such as the green space area (A), perimeter (P), landscape shape index (LSI), and mean enhanced vegetation index (MEVI) had different degrees of influence on the cooling effect of green space and its stability. Green spaces with a high MEVI had a stronger cooling effect and stability. Based on this, planning suggestions such as increasing vegetation amount, maintaining green space area, optimizing green space morphology, and focusing on blue-green space are proposed to enhance the cooling effect of urban green space and its stability, which would improve the thermal environment of the city and enhance the comfort of residents. This study provides a reference basis for the scientific planning of urban green space and provides a scientific basis and practical guidance for the sustainable development of the city.