Assessment of the Climate Resilience of Urban Form Against Thermal Stresses (Case Study: Valiasr Neighborhood, Tabriz))

1. Introduction



Climate change and the intensification of global warming have become critical challenges for cities worldwide. Increasing heatwaves, changing precipitation patterns, and the amplification of urban heat island effects threaten the livability and sustainability of urban environments. These stressors heighten energy demand and reduce the natural capacity of cities to maintain thermal comfort. Urban morphology—defined by density, street proportions, and spatial configuration—directly affects heat exchange, solar access, and airflow, shaping cities’ resilience.



In Iran, this issue is acute in Tabriz, where the desiccation of Lake Urmia has increased thermal stresses and altered energy consumption patterns. Yet, most prior studies have examined building energy or outdoor comfort separately (Taleghani, 2018; Sharifi & Yamagata, 2021; Colaninno et al., 2025). This study bridges that gap by evaluating how morphological parameters jointly affect energy performance and thermal comfort over a 30-year horizon, assessing the climatic resilience of urban form under future extremes.



2. Materials and Methods



An applied-developmental approach combining parametric modeling and future climate analysis was used. The Valiasr neighborhood of eastern Tabriz—a planned, medium-density district—was selected for its morphological regularity and exposure to intensified heat due to Lake Urmia’s drying.



Downscaled datasets for 2025–2055 under RCP4.5 and RCP8.5 scenarios informed four conditions: Normal (current), Base, Warm, and Cold. Using Ladybug Tools and EnergyPlus in Grasshopper, simulations of energy demand and thermal comfort were performed. Morphological variables included building height, block size, coverage, façade transparency, density, and height-to-width ratio. Two indices were developed: the Energy Shock Index (ESI), indicating percentage increases in energy use, and the Thermal Resilience Index (TRI), showing the share of naturally comfortable hours.



3. Results and Discussion



Results show intensified thermal and energy stresses in future scenarios. Current energy use intensity (EUI) is 138.07 kWh/m², dominated by heating (76.37 kWh/m²). In the Base, Warm, and Cold scenarios, energy demand rises by 17.6%, 27.8%, and 41.5%, respectively, with heating loads up by 55% in the cold case. Thus, climate change increases reliance on mechanical systems, undermining energy resilience.



Thermal comfort currently covers 32.7% of annual hours, dropping to 26.5% in future projections, while heat stress nearly doubles (from 10.7% to 18.7%). The Base scenario shows the highest resilience (0.65), the Cold the lowest (0.53). Morphologically, medium-density, fine-grain blocks with balanced height-to-width ratios and connected streets enhance resilience, whereas large blocks and deep canyons heighten vulnerability.



4. Conclusions



The study concludes that the climatic resilience of the urban form in Tabriz will show a declining trend over the next three decades, with the cold extreme scenario exerting the greatest stress on energy systems due to rising heating demands. Although warm scenarios intensify cooling loads and reduce comfort hours, cold-related energy shocks represent the more critical vulnerability.

To enhance resilience, urban policies should prioritize climate-responsive design strategies, including improved insulation, passive ventilation, shading optimization, and the diversification of open and green spaces to moderate microclimates. Encouraging balanced urban densities, fine-grain morphology, and energy-efficient systems can mitigate future energy shocks.

Ultimately, true resilience cannot rely solely on technological or infrastructural solutions; it must emerge from a morphological foundation that harmonizes urban form with climatic realities. Embedding this understanding within urban design frameworks enables cities like Tabriz to better adapt to an uncertain climatic future and safeguard the comfort, health, and sustainability of their residents.