Humidity-driven air-conditioning energy demand changes in global cities under climate change

As climate change causes more frequent and intense humid heat extremes across the globe, air conditioning (AC) is quickly becoming a necessity that we rely on for cooling as well as dehumidification. However, our understanding of the climate change impact on humidity-driven demand changes is limited over large spatiotemporal scales. This puts climate-sensitive energy planning and future-conscious building design at risk. Here, we dynamically model urban buildings’ latent heat load and the associated dehumidification energy in the urban building energy model of the Community Earth System Model to quantify the AC energy demand for maintaining indoor comfort and health under climate change. We show latent heat load increases by 47% globally under climate change, but its relative contribution to total AC energy demand shows spatially diverging trends. AC energy sensitivity to temperature increases exponentially with humidity regardless of climate zones. Mildly hot and highly humid days may see unexpected demand spikes, and this effect is further amplified by climate change. The interplay of climate-driven temperature and humidity changes leads to divergent humidity-driven shifts in the building energy design space. These results have critical implications for energy planning in preparation for rapid urbanization in the Global South. Our study underscores the importance of dynamically and explicitly modeling urban climate-energy interactions for comprehensive climate risk assessment and climate-aware infrastructure planning.