As climate change drives more frequent and intense weather, finding new ways to adapt can be a matter of life or death. A new Stanford-led study reveals a steady increase in the number of people at risk from tropical cyclones and the number of days per year these potentially catastrophic storms threaten health and livelihoods. The findings could help relief agencies, development banks, and other organizations plan more effective strategies for mitigating extreme weather impacts.

“Understanding the demographics of populations exposed to cyclones is crucial for understanding evolving risks,” said study lead author Renzhi Jing, a postdoctoral scholar in the Stanford School of Medicine. “It’s particularly important for risk mitigation and achieving other socially desirable objectives, such as education and poverty alleviation.”

Tropical cyclones are rotating systems of clouds and thunderstorms that produce strong winds and heavy rain. Estimates of exposure to tropical cyclones are often regional rather than global, and do not consider population vulnerabilities. Researchers from Stanford, the RAND Corporation, and other institutions used a new model to combine demographic estimates with tropical cyclone wind fields estimates to construct a global profile of the populations exposed to these storms between 2002 and 2019.

The analysis found that approximately 560 million people are exposed to cyclones yearly, the number of people exposed has increased across all cyclone intensities, and the average age of those exposed has shifted away from children toward people over 60. It also found that populations exposed to tropical cyclones tend to be more socioeconomically deprived than those unexposed within the same country, and this relationship is more pronounced for people exposed to higher-intensity storms.

The findings suggest tropical cyclones can worsen existing inequalities, and highlight the need for targeted interventions to support vulnerable groups, according to the researchers.

“Severe storms hit the poor the hardest, and could worsen socioeconomic and health inequalities,” said study senior author Eran Bendavid, an associate professor of health policy in the Stanford School of Medicine and a senior fellow at the Stanford Woods Institute for the Environment. “Interventions for mitigating tropical cyclone impacts should address this vulnerability.”

The research was funded by the National Institutes of Health.

Study coauthors also include Sam Heft-Neal, a research scholar at the Stanford Center on Food Security and the Environment; Daniel Chavas of Purdue University; Max Griswold, Zetianyu Wang, Aaron Clark-Ginsberg, and Zachary Wagner of the Rand Corporation; and Debarati Guha-Sapir of UC Louvain and Johns Hopkins University.

Rob Jordan is the associate editor, environment and sustainability, at the Stanford Woods Institute for the Environment.