Thermal analysis and environmental assessment of urban quality in a Mediterranean climate. “Case of the medina of Algiers”

Historic cities like the Casbah of Algiers are facing increasing environmental challenges due to climate change and rapid urban transformations. This research investigates the thermal dynamics of this historic urban fabric, focusing on the interplay between urban morphology, microclimate, and outdoor thermal comfort. The objective is to assess the effectiveness of traditional passive strategies and explore the integration of nature-based solutions (NBS) to enhance pedestrian comfort while preserving the architectural and cultural integrity of the site. The study employs a multi-method approach, combining in situ measurements, numerical simulations (ENVI-met), and algorithmic modeling. Physiologically Equivalent Temperature (PET) is used as the primary thermal index to evaluate comfort levels under current and future climate scenarios (2050 and 2090). The effectiveness of shading, urban vegetation, and adaptive design strategies is analyzed through comparative simulations. Preliminary findings suggest that compact morphology and traditional materials offer significant thermal advantages, but increasing temperatures due to climate change exacerbate heat stress. The integration of NBS, such as strategic greening and shading structures, has the potential to mitigate urban heat islands while maintaining heritage authenticity. This research contributes to the discourse on sustainable urban heritage conservation by providing a decision-making framework for urban planners, architects, and policymakers. By bridging the gap between climate resilience and heritage preservation, the study offers actionable insights for the adaptation of historic cities in Mediterranean and arid climates.