Wildfires akin to those that visibly devastated parts of Greece, Siberia and North America this year are also invisibly taking a deadly toll on human health. The fraction of deaths linked to short-term exposure to smoke released by the fires are 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, Australia.
Guo and colleagues took data on daily deaths for all causes across 749 cities in 43 countries between 2000 and 2016, and matched those against modelling of how much those people were exposed to tiny particulates (PM2.5) released by wildfires. The team 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 be about 0.91 per cent.
Guatemala had the biggest fraction 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, along with Greece on 0.33 per cent, despite recent wildfires in these countries.
However, the absolute number of global deaths linked to wildfire smoke is likely a significant underestimate as the analysis does not include many countries regularly plagued by wildfire pollution, such as Indonesia and Malayisa. More widespread monitoring of PM2.5 on the ground would help paint a more precise figure, Guo says.
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 two groups during fire seasons.
And he says his new research offers yet another reason to tackle climate change, because it is fuelling wildfires: “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
Take our expert-led online sustainability course to find out how green living can help tackle climate change
More on these topics: