Does the urban heat island effect matter in the global future cooling energy demand?

Cooling energy demand can be increased significantly due to the global temperature rise, with substantial economic impacts. However, many existing studies have primarily focused on overall temperature increases while neglecting critical mechanisms such as humid heat, daily temperature variability, and the urban heat island (UHI) effect. In this study, we focus on quantifying UHI intensities across different climate zones and integrating these effects into future cooling energy demand projections.

We first analyzed current Land Surface Temperature variations by Local Climate Zone (LCZ) within each climate zone to identify the seasonal and diurnal UHI intensity patterns based on LCZ composition. These observed UHI patterns were then applied to estimate future gridded Cooling Degree Days (CDD) using CMIP6 climate projections. We defined the UHI-adjusted CDD as a comprehensive metric that encapsulates the impact of urban heat islands on cooling demand.

These UHI-adjusted CDD values were then exogenously provided into the AIM/Hub model, which is CGE based global integrated assessment model to simulate climate policies, to project global future cooling energy demand and evaluate associated regional economic impacts. Our findings represent one of the first systematic evaluations of how LCZ-dependent urban heat islands may modulate future cooling energy requirements under various climate change scenarios. This study provides critical insights for policymakers and urban planners aiming to mitigate the economic burden of rising cooling energy demands in a warming world.