Hotspots of Multi-hazard Risk to Human Health in a Changing Climate

The health effects of climate change, from intensified heatwaves to increased environmental suitability for infectious diseases, have become increasingly evident in recent years. In this study, we investigate the intersection of multiple climate-related health hazards from 2003 to 2022 using indices from the Lancet Countdown on Health and Climate Change, including heatwaves, drought, malaria, and wildfire smoke exposure. Through a global analysis at a 0.25-degree resolution, we identify regions where these hazards have overlapped, highlighting hotspots of simultaneous exposure. We then perform detailed case studies in countries most affected by these hazards, where we explore the interactions between seasonal climate variations, demographic shifts, and the exposure to health hazards. The findings of this study can help guide health system adaptations and inform policy by revealing where, when, and whom these hazard combinations affect. Finally, while the health effects of some of these combinations have been studied, the compounding effects are generally unknown. Mapping their co-occurrence can help in designing relevant epidemiological studies to better understand these consequences.