Cali Urban Development II: Investigating the Impacts of Land Use Change on Urban Heat and Social Vulnerability in Cali, Colombia

The surface urban heat island (SUHI) effect is an environmental phenomenon resulting in cities with higher temperatures than rural areas due to increased pavement and decreased cooling from vegetation. The city of Santiago de Cali in Colombia faces SUHI challenges exacerbated by land use change. The Cali municipal government agency, Departamento Administrativo de Gestión del Medio Ambiente, and the community organization Fundacion Dinamizadores Ambientales partnered with NASA DEVELOP to evaluate communities in Cali most vulnerable to urban heat. This project illustrated the utility of using NASA Earth observations to evaluate the relationship between land use, temperature, and social factors in Cali, Colombia between 2013 and 2023. The team used Landsat 7 Enhanced Thematic Mapper Plus (ETM+), Landsat 8 Operational Land Imager (OLI) and Thermal Infrared Sensor (TIRS), and Landsat 9 OLI-2/TIRS-2 to generate land surface temperature (LST) maps in Google Earth Engine through NASA DEVELOP’s Urban Heat Exposure Assessment Tempe 2.0 tool. Cloud cover limited the project feasibility, but it improved with Landsat 9 data. In ArcGIS Pro, the team found that LST was significantly higher in urban areas than in wetlands or forests. Using R Studio, the team ran a principal component analysis and found that health care and green space access were negatively correlated, and Afro-Colombian ethnicity was positively correlated with LST. With knowledge of the most impacted and vulnerable regions, the partner organizations can prioritize establishing healthcare facilities and green spaces in those areas to reduce the impacts of urban heat.