Impact of future urbanization on a hot summer: a case study of Israel

Israel's population is projected to increase significantly through the middle of the current century, requiring further expansion of the built environment to accommodate additional inhabitants and accompanying urban infrastructure. This study examines the climatic impacts of future urban expansion through simulated near-surface temperature and energy flux components associated with built environment growth. The Weather Research and Forecasting model was used to simulate present day extreme summertime conditions, at 1-km resolution, utilizing contemporary urban representation. To determine impacts associated with the physical growth of the urban environment, sensitivity simulations, also at 1-km resolution, incorporating projected changes in urban areas for Israel-based national development plans, were performed. Spatially and diurnally averaged at the national scale, projected urbanization is shown to increase summertime temperatures 0.4-0.8 A degrees C, with greater temperature rise in northern compared to southern parts of the country. Across the diurnal cycle, urban impacts on near-surface warming are minimal during daytime hours, but exceed 3 A degrees C across many urban locales during nighttime hours. The results presented here demonstrate the spatio-temporal impact of future urban expansion in Israel on temperature. The magnitude of these changes highlight the need for strategically designed regional and national planning to alleviate potentially deleterious climatic impacts associated with the physical growth of the built environment.