This study assesses the spatial and temporal characteristics of nighttime surface urban heat island (SUHI) effects over Greater Cairo: the largest metropolitan area in Africa. This study employed nighttime land surface temperature (LST) data at 1 km resolution from the Moderate Resolution Imaging Spectroradiometer (MODIS) Aqua sensor for the period 2003–2019. We presented a new spatial anomaly algorithm, which allowed to define SUHI using the most anomalous hotspot and cold spot of LST for each time step over Greater Cairo between 2003 and 2019. Results demonstrate that although there is a significant increase in the spatial extent of SUHI over the past two decades, a significant decrease in the mean and maximum intensities of SUHI was noted. Moreover, we examined the dependency between SUHI characteristics and related factors that influence energy and heat fluxes between atmosphere and land in urban environments (e.g., surface albedo, vegetation cover, climate variability, and land cover/use changes). Results demonstrate that the decrease in the intensity of SUHI was mainly guided by a stronger warming in daytime and nighttime LST in the neighborhood of urban localities. This warming was accompanied by a decrease in surface albedo and diurnal temperature range (DTR) over these areas. Results of this study can provide guidance to local urban planners and decision-makers to adopt more effective mitigation strategies to diminish the negative impacts of urban warming on natural and human environments.

Environmental sustainability projects are essential for preserving natural resources and enhancing quality of life for present and future generations. This cross-sectional study examined Saudi residents’ knowledge and awareness of green projects, attitudes and perceptions toward them, personal environmental behavior and participation, and perceptions of institutional and societal roles. A questionnaire was administered to 1044 participants from various regions across Saudi Arabia. Descriptive statistics, including means and standard deviations, together with the Mann–Whitney U test, Kruskal–Wallis H test, and Dunn’s post hoc test, were used to answer the research questions and test the hypotheses. The findings indicated generally positive responses across the four dimensions; at the item level, most items fell within the agree range, while neutral ratings appeared mainly in items related to following green-project news, reviewing related policies, using low-emission transportation, and the perceived sufficiency of institutional communication. Significant differences were observed in the overall questionnaire and several dimensions according to gender, favoring females, and according to nationality, favoring Saudi participants. Regional differences were limited to the environmental behavior and personal participation dimension, whereas educational qualification did not produce significant differences. The absence of educational differences suggests that green-project awareness and behavior may be shaped not only by formal educational level, but also by national campaigns, media exposure, and shared public discourse. The study provides a countrywide empirical baseline for green-project awareness, attitudes, and environmental behaviors in Saudi Arabia and identifies areas for more targeted communication, regional engagement, and longitudinal research.