How long does vegetation take to reach peak cooling in São Paulo (Brazil)?

With urbanisation, cities face increasing temperatures, which are further increased by climate change. In this context, urban greenery can be a strategy to reduce surface temperatures in cities, providing cooling through shade and evapotranspiration. However, little is known about how long different types of urban greenery take to reach their maximum surface temperature reduction capacity in different climates across the world. To fill this gap, we previously developed a method using remote sensing data to quantify this time span, calling it “Cooling Establishment Time” (CET). To increase the number of case studies to those previously investigated in Zurich (Switzerland), our main challenges are to automate the identification of green areas, their selection, and quantification of their cooling dynamics through time in a computationally effective way. As a starting point, this ongoing research quantified the Cooling Establishment Time of green areas in São Paulo (Brazil), generating new information about this time measurement in a different climatic and urban context. São Paulo’s green areas took around 6 to 20 years to reach peak Land Surface Temperature reduction, which were longer than the time spans identified in Zurich. This contrast may be explained by the differences in local predominant vegetation and built environment. We expect to generate a dataset of green areas’ Cooling Establishment Times throughout different cities in the world, leading to a better understanding of what drives the temporal dynamics of vegetation cooling. Such results can be useful for policymakers to best plan green areas, improving heat mitigation and adaptation strategies depending on local environmental conditions and social needs.