Quantifying the Spatial Extent of Green Infrastructure’s Cooling Influence in Urban Areas

Green Infrastructure (GI) is well known for its role in mitigating urban temperatures, but quantifying its effects through measurements remains challenging, particularly in surrounding areas. One major difficulty lies in the fact that, while trees grow slowly and their cooling impact evolves gradually, urbanized areas are heterogeneous and tend to change rapidly, overshadowing GI’s contribution. The Metropolitan Region of São Paulo (RMSP), Brazil, was build in the Atlantic Rainforest biome, a dense and relatively homogeneous forest that exemplifies the best cooling effect GI could achieve. A significant portion of the RMSP remains covered by preserved rainforest. In this study, we analyzed mean Land Surface Temperature (LST) and mean Normalized Difference Vegetation Index (NDVI) over two decades (1985-1995 and 2015-2025), derived from Landsat data (30 m resolution, converted to 10:00 AM), to assess how LST changed in the surroundings of three sites where dense vegetation was removed between decades but that still border a large portion of preserved rainforest. The new land uses are (A) compact low-rise buildings, (B) large low-rise structure, and (C) a highway. For each site, we performed a perpendicular cross-section to the border and computed the distance between the last point with statistically significant NDVI decrease and the last point with significant LST increase over vegetation. The results were (A) 136 m, (B) 168 m, and (C) 128 m to the northwest and 64 m to the southeast (where NDVI increased over vegetation in the last case). These findings provide insight into the maximum extent to which GI influences surrounding LST, considering that restoring land cover to its original state constitutes a GI implementation, with the first-decade mean LST serving as an estimate of its impact, assuming that its spatial influence over a homogeneous forest is similar to that over an urbanized area.
Acknowledgments: Fapesp grant 2021/11762-5