Global Assessment of Compound Tropical Cyclone-Heat Hazards in a Changing Climate

Tropical cyclones (TCs) and extreme heat each pose risks to the public individually, and even more so in combination. TCs cause strong winds, intense precipitation, and storm surges that can result in widespread destruction and mortality. TCs often lead to power outages, which amplifies the risk of extreme heat exposure by disabling cooling systems. As anthropogenic climate forcings are projected to increase the frequency and severity of heat extremes and drive more intense TCs, understanding the joint hazard of TC-heat compound events is essential for assessing future risks posed to human health. Prior studies have employed observations, statistical-dynamical TC models, and regional weather models to explore TC-heat risks, but there is still a limited understanding of these compound event hazards across the globe. In this study, we conduct a comprehensive global analysis of historical and future TC-heat compound events using the fully dynamical, TC-permitting GFDL CM2.5-FLOR (FLOR) global climate model (50 km land/atmosphere resolution). We use a 10-member ensemble of FLOR historical simulations, validated against historical observations, to analyze past and present TC-heat compound events. This analysis allows for the assessment of the hazards posed by TC-heat compound events under current climatic conditions using a larger sample size of events than the instrumental record alone, while also capturing the dynamical processes that couple TCs and extreme heat. We investigate future behavior of TC-heat events with an analogous ensemble of FLOR simulations following RCP4.5 boundary conditions. We identify high-risk areas for TC-heat compound events and examine how spatial patterns of risk evolve over the next century. This project constrains the risks of TC-heat compound events across the globe in order to identify hotspots of risk and motivate applicable extreme weather warning systems and adaptation strategies in the present and with climate change.