Uncertainty in Tropical Cyclone Projections Linked to Uncertainty in Tropical Cloud Feedback

Projections of future tropical cyclone frequency span a wide range of possibilities, ranging from a slight increase to a considerable decrease according to climate models. At the same time, estimation of how the cloud radiative feedback is also uncertain across climate models. These two uncertainties have historically been studied independently as they concern different space and time scales: one quantifies the extreme weather and the other the large-scale climate. Here we show that these two uncertainties are not independent; they are both influenced by the response of tropical clouds to warming. Across climate models, we discovered a negative correlation between the shortwave cloud radiative feedback and the change in the frequency of seed vortices, which are tropical cyclone precursors that are abundant enough to impact the climate. We perform high-resolution simulations to show that the correlation holds across different cloud response patterns and sea surface temperature variation patterns. The results suggest that models with more significant surface warming tend to show a more substantial reduction in tropical cyclone frequency. This constraint holds implications for the aggregated global tropical cyclone hazards: the Earth system is unlikely to evolve into a state having significant enhancement in both surface temperature and tropical cyclone frequency.