Wildfire Smoke Deaths Far Higher Than Known

Wildfire smoke is an emerging nationwide crisis for the United States, supercharged by climate change. A growing body of evidence reveals that these conflagrations are killing far more people than previously known as smoke travels hundreds or even thousands of miles.

Recent studies estimate that wildfire haze currently kills 40,000 Americans annually, a figure projected to rise to 71,000 by 2050. One analysis of Los Angeles infernos suggested the death toll was 440 or more, significantly higher than the official tally of 30. Additionally, new data indicates global wildfire emissions may be 70 percent higher than previously believed.

These findings illustrate the desperate need to protect public health through better air quality monitoring and understanding the impact of smoke on populations far from the flames.

Two studies published last month paint a grim picture of the wildfire crisis in the U.S. and elsewhere. The first study revises global wildfire emissions estimates based on new satellite data, noting that previous monitoring was somewhat limited.

Satellites previously broke landscapes into 500-meter squares. If a wildfire did not fully fill that space, it was not counted. The new study increases that resolution to 20 meters in key fire regions, capturing multitudes of smaller fires.

While individual smaller blazes do not produce as much smoke as massive conflagrations, they add up significantly. According to Guido van der Werf, a wildfire researcher at Wageningen University & Research and lead author of the paper, these smaller fires "basically double the amount of burned area we have globally."

The previous estimate of charred land was around 400 million hectares annually. Adding small fires bumps that up to 800 million hectares, roughly the size of Australia. In some regions, such as Europe and Southeast Asia, the burned area triples or even quadruples with this improved resolution.

Consequently, annual wildfire emissions are now estimated at 3.4 gigatons of carbon, up from the previous thought of 2 gigatons. This represents a significant portion of what humanity produces from burning fossil fuels.

The type of fire and its location dramatically affect emissions. A forest fire contains vast biomass—brushes, grasses, trees, and soil—converted into carbon dioxide, methane, and particulate matter. In contrast, a prairie grass fire has much less fuel.

Burn rates also vary. Flames may race through woodland, while carbon-rich peat can smolder for days or weeks. These peat fires are so persistent they can remain hidden under snow and reappear when temperatures rise, a phenomenon scientists call "zombie fires."

"It really matters where you're burning and also how intense the fire can become," van der Werf said.

Small fires often remain small due to landscape fragmentation, such as roads preventing spread, and human intervention. A history of fire suppression means fires are often quickly extinguished. Ironically, this has helped create larger monsters by allowing vegetation to build up, disrupting the natural cycle of low-intensity fires that clear dead brush.

Populated regions produce many smaller fires due to ignition sources like cigarette butts, electrical equipment sparks, and chains dragging from trucks. While these fires are less destructive than behemoths, they are frequent near human habitation and have health impacts.

The second recent study focuses on the health impacts of smoke, specifically regarding childhood asthma in Vermont. Researchers compared the smoky year of 2023 to clearer years, analyzing PM 2.5 (particulate matter smaller than 2.5 millionths of a meter) from wildfires in Quebec, Canada.

According to Anna Maassel, a doctoral student at the University of Vermont and lead author of the study, PM 2.5 is "especially challenging to dispel from lungs, and especially irritating to those airways." Research indicates exposure to wildfire smoke can have long-term impacts, including the development of asthma in children.

This specific study examined the exacerbation of asthma symptoms in children already living with the condition. The findings underscore the danger of smoke traveling across borders, significantly worsening air quality and health outcomes in regions distant from the actual fires.

The convergence of data from multiple studies confirms that wildfire smoke is a severe national and global crisis. The death toll is likely vastly underestimated, and emissions are significantly higher than previously calculated.

With projections showing potential annual deaths rising to 71,000 in the United States alone, the need for effective public health measures is urgent. Better monitoring of air quality with networks of sensors and a re-evaluation of fire management strategies are essential steps to mitigate this growing threat.