Cyclones are increasing as the climate warms – and they remain deadly up to a month after the event, study finds
As Queensland prepares for another potential cyclone – and with more intense tropical cyclones expected in the future due to a warming climate – our planetary health researchers have found that there is an increased risk of dying from cardiovascular and respiratory illness for up to 30 days after the cyclone event. In Australia this risk lasts for ten days.
Except for the immediate physical impacts such as drowning and injuries, tropical cyclones also cause death via medical support disruptions, environmental contamination, and psychosocial stress.
The study, led by Professor Yuming Guo and published in the journal, PLOS Medicine, found a rise in mortality around 20 days after a cyclone in most countries and 30 days in the US, Brazil and Taiwan. Australia and New Zealand locations experienced an average period of less than ten days following a cyclone when the risk of all-cause mortality increased. However, a more prolonged period of concern, spanning over 17 days, for increased mortality risk from heart and respiratory problems, was found after a cyclone in Australia and New Zealand.
The research team looked at death from all causes, including cardiovascular and respiratory episodes mortality among the general population living in 494 locations in 18 countries or territories during 1980 to 2019, and cross referenced that with tropical cyclone events.
Overall, 47.7 million all-cause, 15.5 million cardiovascular, and 4.9 million respiratory deaths and 382 tropical cyclones were included in the analyses. An advanced modelling framework was used to estimate the mortality risks and duration of the risks for each tropical cyclone event in each location.
Every year around 150 million people are exposed to tropical cyclones and this will have greater impact with continued growth in coastal populations and global warming, according to Professor Guo. “Warmer surface ocean will also likely fuel more powerful tropical cyclones with higher windspeed and precipitation,” he said.
“It’s crucial to incorporate epidemiological evidence to quantify the mortality risk and duration of the risk for each country associated with tropical cyclones to better understand the health effects and respond to the potentially increasing hazards.”
The study found that:
- Tropical cyclones exhibit great variation in the mortality risk and risk duration, depending on the characteristics, location and year.
- On average there is an increased risk of dying for 22 days after the cyclone has passed, but extended to over 30 days for the USA, Brazil, and Taiwan.
- The mortality risk of a cyclone increased linearly with the maximum sustained windspeed and cumulative rainfall in most of the countries.
- Particularly high death risk from respiratory problems was observed in Australia and New Zealand after a cyclone, which increased over 30% after cyclones passed.
- No significant temporal pattern was found for the cyclone-related mortality risks in Australia, while the cyclone-related all-cause and cardiovascular mortality risks in New Zealand appeared to be increasing over time.
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