Urban Heat Islands and Social Vulnerability in a Large City in Northeastern Brazil

This research aims to model urban heat islands in Natal, located on the coast of northeast Brazil, and to relate their spatial distribution to social vulnerability. Natal has a population of 750,000. The modeling of its urban heat islands was conducted using a database of thirty days of field data collected with fifteen thermometers. The Local Climate Zones (LCZ) of the study area were delineated using the R package LCZ4r. After delineating the LCZs, the temperature data were interpolated. Social vulnerability levels were calculated based on social data collected in the most recent national census, at the census tract level. Eight social variables were used to compose the index, covering income, education, age, and race. Each census tract in the city was classified by its level of social vulnerability on a scale from one (slightly socially vulnerable) to ten (highly socially vulnerable). The temperature data were then overlaid with the social vulnerability data. In the most socially vulnerable regions, there are few green spaces, the areas are more densely occupied, and urban structures such as parks and squares are rarely present, leading to higher temperatures. In areas with lower social vulnerability, the roads are wider, the blocks are less densely occupied, and green spaces are more prevalent, contributing to cooler temperatures. Furthermore, in the most socially vulnerable areas, the population's capacity to adapt to extreme temperature events is considered lower, making these areas more urgent for the implementation of public policies. This study aims to contribute to the discussion on Urban Climate Justice and to support the implementation of effective urban policies, particularly in the Global South, which faces significant climate and social challenges.