We employ a high-resolution nested climate modeling system to test the potential response of air stagnation events in the United States (U.S.) and South Asia to enhanced global greenhouse forcing. We find that enhanced greenhouse forcing causes the occurrence of stagnation days to increase over most of the continental U.S., with maximum increases of 50% occurring over the southeast. Over South Asia, increases of up to 50% (or more) occur over the northwest region, while decreases of up to 50% (or more) occur over much of India, Bangladesh, Sri Lanka, and Myanmar. The spatial heterogeneity of the stagnation response over both the U.S. and South Asia highlights the potential importance of fine-scale climate processes in determining the response of air pollution episodes to continued global warming. When coupled with enhanced emissions, the lower surface winds, higher temperatures and lower mixing heights associated with stagnation events are likely to contribute to degraded air quality, with associated human health impacts.