ISPRS-SELPER: Tackling Urban Heat Islands in Latin America through Collaborative Research

Latin America is among the most urbanized regions in the world. SELPER,  a Latin American  non profit organization is interested in contributing to a better understanding of climate-related problems using Earth Observation and remote sensing data. This collaborative research by ISPRS and SELPER researchers responds not only to the intensification of the urban heat island (UHI) effect caused by the rapid development of cities in recent decades, but also recognizes the importance of preserving and restoring critical blue-green infrastructure to mitigate the effects of climate change. 

During a first stage, the study focused in 16 major Latin American megacities present at 6 countries, collectively home to approximately 73 million people: São Paolo (22.62), Mexico City (22.28), Buenos Aires (15.69), Río de Janeiro (13.73), Bogotá (11.51), Lima (11.2), Santiago (6.9), Belo Horizonte (6.25), Guadalajara (5.42), Monterrey (5.12), Brasilia (4.87), Recife (4.26), Porto Alegre (4.21), Medellin (4.1), Salvador (3.96) and Curitiba (3.81). Each city was mapped and analyzed using Google Earth Engine and remote sensing data. The analysis included Land Surface Temperatures (LST) and Local Climate Zones (LCZ) for the years 2003, 2008, 2018 and 2021. Preliminary results explored the UHI distributions and the impact of different levels of urban development by LCZ.  

First-stage acchievements indicate, that these megacities exhibit: (1) a diffuse urban model, (2) urban heat islands are spatially and temporally located, (3) compromised green-blue infrastructure during the last decades, and (4) differences in construction materials and morphological changes among surface structures. 

Collaboration is needed. For the second stage the researcher's group is developing green-blue infrastructure models for each city, such as the Urban Canopy Model (UCM), Riparian Infrastructure Model (RIM) and/or Urban Green Areas (UGA). These models will be based on a fusion of Earth Observation, remote sensing data and local knowledge. Moreover, important information will be retrieved, such as meteorological local station data and socioeconomic information. 

In summary, collaborative efforts could achieve potential results to create the basis for implementing preventive policies for sustainable planning, promoting climate justice, and adopting nature-based solutions in Latin American megacities.