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New research published in Science Advances has revealed a significant rise in infant mortality in low- and middle-income countries following exposure to tropical cyclones, including those below hurricane or typhoon strength. The findings highlight an urgent need for stronger disaster response measures and child health protections, particularly as climate change increases the frequency and intensity of severe weather events.
The study found that infants exposed to tropical cyclones either in the womb or within their first year of life were markedly more likely to die. On average, infant mortality rose by 11 per cent compared to baseline levels — an increase of 4.4 deaths per 1,000 live births.
The elevated risk was most acute within the first year after a storm and appeared to subside after two years. However, the precise reasons behind the mortality rise remain unclear.
“The fact that health care use and undernutrition were not affected by tropical cyclone exposure suggests that the mortality effects are driven by other factors that we could not directly study,” said lead author Dr Zachary Wagner, associate professor (research) of economics at the USC Dornsife College of Letters, Arts and Sciences, and senior economist at its Centre for Economic and Social Research.
The research team, which included academics from the RAND Corporation, Stanford University, Johns Hopkins University, and UCLouvain in Belgium, also noted that the mortality increase was linked not only to major storms but to more frequent, lower-intensity tropical storms.
“Some of the countries had only a few Category 3 or higher storms during the period we studied,” said Zetianyu Wang, a PhD student at RAND and the report’s first author. “But that doesn’t mean the impact of larger storms is absent. As the planet warms, we risk more tragedies across the globe if measures aren’t taken to protect children in the poorest countries.”
Researchers analysed nearly 1.7 million child health records across seven low- and middle-income countries: Bangladesh, India, Madagascar, Cambodia, the Philippines, the Dominican Republic and Haiti.
While the average increase in infant mortality was 11 per cent, the effects varied widely between countries. Bangladesh, Haiti and the Dominican Republic experienced increases of more than 10 deaths per 1,000 births following cyclones. In contrast, little to no increase was recorded in India, Madagascar, Cambodia and the Philippines.
Dr Wagner suggested these differences could stem from disparities in geography, housing, and public health systems.
“Some countries may be helped by mountainous terrain, while others have more flood-prone areas,” he explained. “Disaster preparedness, evacuation efforts, the sturdiness of housing, and pre-existing child health conditions all likely play a role.”
Understanding why some countries are more resilient than others will be a major focus of further investigation.
“If we want to protect children from the growing threat of climate-linked disasters,” Wagner added, “we need to understand not just where the risk is greatest, but why.”