Wildfires akin to those that devastated parts of Greece, Siberia and North America this year are also taking an invisible but deadly toll on human health. The proportion of deaths linked to short-term exposure to smoke released by the fires is nearly as high as those from heatwaves, a new estimate suggests.
“This is a little bit of a surprise because wildfires are not very frequent. Smoke is a serious problem [for public health],” says Yuming Guo at Monash University in Melbourne, Australia.
Guo and his colleagues matched data on daily deaths from all causes across 749 cities in 43 countries between 2000 and 2016 against modelling of how exposed those people were to tiny particulates (PM2.5) released by wildfires. They linked 33,510 of 65.6 million total deaths a year to the wildfire pollution, or 0.62 per cent of all deaths, after adjusting for other possible explanations such as temperature. By contrast, heat-linked deaths are estimated to make up about 0.91 per cent of deaths.
Guatemala had the highest percentage of deaths linked to PM2.5 released by the fires, at 3.04 per cent, followed by Thailand, Paraguay, Mexico and Peru. The US had a relatively small percentage, at 0.26 per cent, as did Greece at 0.33 per cent, despite recent wildfires in these countries.
However, the absolute number of global deaths linked to wildfire smoke is probably a significant underestimate, as the analysis doesn’t include many countries that are regularly plagued by wildfire pollution, such as Indonesia and Malaysia. More widespread monitoring of PM2.5 on the ground would help paint a more precise figure, says Guo.
A separate study by Guo and another team, looking at the impact of wildfire pollution in Brazil on different age groups, suggests that children and older people are more vulnerable to its effects. Guo says governments should focus resources on those groups during fire seasons.
The new research offers yet another reason to tackle climate change, because it is fuelling wildfires, says Guo. “The fundamental thing is to reduce the bushfires, and that means a reduction of our CO2 emissions.”
Journal reference: Lancet Planetary Health , DOI: 10.1016/S2542-5196(21)00173-X
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