Mapping urban heat dynamics in Sub-Saharan Africa: a multi-city analysis of drivers of urban heat island across African cities

Urban heat island (UHI) effects are intensifying across Sub-Saharan Africa (SSA), increasing climate vulnerability in rapidly urbanizing cities with limited adaptive capacity. However, comparative evidence on the drivers and dynamics of urban heat across SSA remains limited. This study examines the spatiotemporal dynamics of UHI and the influence of land-use and land-cover (LULC) characteristics on thermal stress in Johannesburg, Nairobi, Lagos, and Kinshasa between 2000 and 2024. Landsat-derived land surface temperature (LST), and open-access LULC datasets were integrated with the Urban Thermal Field Variance Index (UTFVI) and spatial-statistical analyses to evaluate relationships between urban heat, built-up areas, vegetation, and water bodies. Results showed substantial variations across cities, with Kinshasa recording the largest increase in mean LST, from 28.68°C in 2000 to 33.93°C in 2024. Built-up expansion was consistently associated with increased thermal stress, with the strongest relationship observed in Johannesburg (r = +0.56), while vegetation cover exhibited significant cooling effects across all cities. Areas transitioning from vegetation to built-up land experienced the greatest increase in UTFVI. These findings underscore the importance of green and blue infrastructure and support climate-responsive urban planning strategies to enhance thermal resilience in rapidly growing African cities.