Cities expansion drivers and maximum temperatures variation in the Tropics

Abstract

Abstract Urban expansion and contemporary climate variations are caused by different proximate and underlying multidimensional factors. A spatiotemporal analysis of the urban socio-ecosystem generates key information for planning a sustainable urban model. We analyzed the spatiotemporal pattern of urban expansion and maximum temperature variations in a hierarchy of four categories of cities in the South American tropics in a sequence of seven-time intervals between 1985 and 2018. We defined the boundaries of 31 cities using spatiotemporal information on climatic, topographic, forest, demographic, and economic dimensions. This information was used to run several linear and nonlinear models that would explain the pattern of urban expansion and maximum temperature variations. We found that the historical pattern of expansion varied over time by city category; however, by the end of the first two decades of the 21st century, expansion was significantly higher for all categories. All dimensions contributed to explaining the expansion. An increasing altitude, the steepness of the slope, and a lower roughness index were the proximate causes of increasing the probability of city expansion; on the contrary, vegetation cover had the least importance, suggesting degradation of peripheral ecosystems. Underlying causes, an increase in the gross domestic product (GDP), and demographic variations were of high importance in explaining the probability of expansion in the region. We suggest that the systematic transition from peri-urban soil to impervious cover in the South American tropics is key to both local and global land surface energy balance.