New research shows that the health consequences of wildfire smoke exposure stretch well beyond the smoky days themselves, contributing to nearly 16,000 deaths each year across the U.S., according to a National Bureau of Economic Research (NBER) analysis released in April.
The analysis warns that number could grow to nearly 30,000 deaths a year by the middle of the century as human-driven climate change increases the likelihood of large, intense, smoke-spewing wildfires in the Western U.S. and beyond.
“This really points to the urgency of the problem,” says Minhao Qiu, a researcher at Stanford University and the lead author. “Based on our results, this should be one of the policy priorities, or the climate policy priority, of the U.S., to figure out how to reduce this number.”
Another analysis, led by researchers from Yale University, finds that the human death toll every year from wildfire smoke could already be near 30,000 people in the U.S. Deaths from cardiovascular disease, respiratory problems, kidney disease, and mental health issues all rise in the days and weeks after smoke exposure.
Together, the studies point to an underappreciated threat to public health, says Yiqun Ma, a researcher at Yale and an author of the second study.
“It’s a call to action,” she says—outlining the real, and significant, human stakes of failing to rein in further human-caused climate change.
Wildfire smoke is rarely listed as a cause of death on people’s death certificates. But research has shown that tiny particles present in smoke worsen many different health problems. These particles penetrate deep into people’s lungs and can cross into the bloodstream or even into the brain.
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Repeated exposures, or high-concentration exposures, can supercharge other health problems, from heart and kidney disease to hastening the onset of dementia symptoms. In some cases, the stress from wildfire smoke is so great that some people die.
Because the harm from wildfire smoke can accumulate and isn’t always immediately obvious, the long-term risks from wildfire smoke exposure have gone underappreciated.
“It’s not obvious, necessarily, if you’re looking at any individual case,” says Sam Heft-Neal, an environmental economist at Stanford and an author of the NBER study. Stepping back and looking at the data statistically makes the picture much clearer, he says: smoke is a big problem that is contributing to thousands of deaths already in the U.S.
Despite the growing understanding of the health risks from wildfire smoke, the costs have not been factored into most policy decisions, says Susan Anenberg, a public health and pollution expert at George Washington University.
The new research adds to a body of work “showing that wildfire smoke is one of the largest public health consequences of climate change,” Anenberg says.
By 2050, the overall annual economic cost credited to lives lost from wildfire smoke could reach $240 billion, according to the NBER analysis. That is larger than previous estimates of all climate-related damages combined—including direct costs related to wildfire and tropical cyclone damages.
“Our estimates of the damages of climate change are undercounting the true effects,” Anenberg says.
