Urban heat islands drive asymmetric energy penalties and seasonal carbon shifts across Morocco's climatic zones

Urban heat islands (UHI) fundamentally reshape the microclimate of cities, yet their cascading consequences on building energy systems and associated carbon budgets have remained poorly constrained, particularly across climatically heterogeneous regions. This study provides a systematic, multi-zone quantification of UHI-driven perturbations to both building thermal performance and carbon footprint across the 6 contrasting climatic regions of Morocco. Results demonstrate that urban thermal anomalies induce marked asymmetries in energy demand: winter heating loads decline by 14.8 − 46.8 % , whereas summer cooling requirements rise by 5.0 − 17.2 % relative to rural reference conditions, with continental arid zones exhibiting the most pronounced deviations. Critically, the carbon accounting framework developed herein confirms the seasonal polarity in urban emission dynamics: UHI systematically suppress carbon outputs in winter by curtailing heating demand, while driving emission surpluses in summer through amplified cooling needs yielding net annual carbon penalties of ₂ ⁻ ² 892.8 − 3,324.3 gCO ₂ m ⁻ ² depending on climatic zone. These results expose fundamental inadequacies in conventional building simulation workflows that rely solely on rural meteorological inputs, with direct consequences for energy rating accuracy and environmental impact assessment. The analysis further illustrates that within these specific climatic contexts, the UHI carbon effect is inherently adverse in summer ( + , emission − enhancing ) and beneficial in winter (−, emission-reducing), a rule validated across a broad spectrum of climatic and morphological configurations. The robustness of urban-corrected weather datasets against field measurements ( ² R² = 0.986 for heating; ² R² = 0.998 for cooling) confirms the operational viability of integrated thermal–carbon assessment frameworks. Together, these findings reposition the UHI as a first-order variable in both building energy balance and carbon accounting, highlighting the necessity of embedding urban microclimate data into local building energy standards.