Past and future impacts of urbanisation on land surface temperature in Greater Cairo over a 45 year period

Abstract

Rapid and unplanned urbanisation can lead to altered local climate by increasing land surface temperature (LST), particularly in summer months. This study investigates the Urban Heat Island (UHI) in Greater Cairo, Egypt, using remote sensing techniques to estimate LST of summer months over 45 years (1986, 2000, 2017, and predicted year 2030). The research objectives and steps were, 1- mapped land use/ land cover (LULC), 2- conducted spatiotemporal analysis of LST, with a comparison of change in LST across different land cover types, 3- predicted future LST for 2030, and 4- examined this temporal change for a hot-spot area (ring road) and a cool-spot area (the River Nile). The results showed that urban areas have increased over the last 30 years by 179.9 km2 (13 %), while agriculture areas decreased by 148 km2 (12 %) and water bodies decreased by 6 km2 (0.5 %). The mean LST over Greater Cairo increased over time, from 31.3 °C (1986) to 36.0 °C (2017) and is predicted to reach 37.9 °C in 2030. While a notable rise of mean LST in the Cairo ring road buffer zone (88 km2), where it was 31.1 °C (1986), and 37 °C (2017) due to the triple increase of urban areas on account of agriculture areas, and the LST it may reach 38.9 °C by 2030. The mean LST increased slightly more in urban hot-spot areas than in cooler cultivated areas. UHI may induce a modification in the local climate that can negatively affect agricultural land, and human thermal comfort and unfortunately lead to a less sustainable environment.