Multiscale numerical assessment of urban overheating under climate projections: A review

Climate change and urbanization have exacerbated concerns about urban overheating, affecting thermal comfort, heat-related mortality, and urban energy consumption, especially during heat waves. Developing climate projections that reliably describe the state of the urban climate, a complex system containing microclimate phenomena on a regional and global scale, is essential for assessing overheating impacts and evaluating mitigation strategies in current and future climates. Using four essential steps for advancing our understanding of overheating and informing future studies, we review climate model projections for urban overheating impact assessments: (1) Acquisition of raw future climate data at the mesoscale through GCM-RCMs; (2) Bias correction and local reference year data generation; (3) Simulations at microscale indoors and outdoors using building performance or CFD models; (4) Evaluation of overheating based on various criteria. A methodology for selecting review articles is presented. The study highlights key future research gaps related to climate data generation, improving data reliability, and addressing climate simulation complexities indoors and outdoors. In addition, a comprehensive overheating assessment also depends upon incorporating social-economic factors into evaluations. Although we focus on urban overheating assessment, the general methodologies of future climate projections may also apply to other building performance simulations considering climate change impacts.