Wildfire smoke contributes to tens of thousands of annual deaths, inflicting greater harm on American residents by mid-century than other climate change-related threats, including extreme heat.

This assertion comes from a new research paper that presents extensive modeling of the increasing health impacts of wildfire smoke on public health in the U.S.

The study, published in Nature magazine on Thursday, reveals an average annual contribution of wildfire smoke, leading to over 41,400 excess deaths—more than twice what previous research had suggested.

By mid-century, the study’s authors project an additional increase of 26,500 to 30,000 deaths as human-driven climate change exacerbates wildfire risks.

Marshall Burke, an environmental and social sciences professor at Stanford University and one of the study’s authors, states:

Economically quantified, Burke mentions that their findings surpassed other financial damages associated with climate change identified in previous studies, including agricultural losses, heat-related fatalities, and energy expenses.

Numerous studies indicate that wildfire smoke exposure results in severe health issues. Tiny smoke particles can infiltrate the lungs and enter the bloodstream, raising the risk of asthma, lung cancer, and other chronic respiratory conditions. Wildfire smoke is also associated with premature births and miscarriages.

This research paints a stark picture of a country increasingly filled with smoke. Fires in the western U.S. and Canada release smoke into the atmosphere, spreading across regions and undermining decades of efforts to curb industrial air pollution through clean air regulations.

Dr. Joel Kaufman, a professor at the University of Washington School of Medicine, commented on the study, noting, “This poses a new threat that can be directly linked to climate change. That’s the crucial point here.”

As the study suggests, wildfire smoke-related deaths could rise by 64% to more than 73%, varying by emission rates.

“Regardless of mitigation efforts, we are likely to experience more smoke by 2050,” Burke added, though emphasizing that emission reduction efforts will have long-term benefits.

Kaufman noted that over the past five to ten years, accumulating evidence indicates that wildfire smoke is at least as detrimental as other forms of air pollution.

“We previously assumed wood burning was less harmful,” Kaufman explained. “These findings indicate that wildfire smoke could be more toxic,” particularly when wildfires consume structures, vehicles, and other human-made materials.

Kaufman highlighted that earlier this year, the Los Angeles fire started from a burning area, but much of it involved homes and plastics, which created “another toxic mixture.” The new research does not differentiate the sources of future wildfire smoke.

The implications of this research could influence public policy.

The Environmental Protection Agency is attempting to revoke a vital legal provision known as “danger detection.” This is part of a broader rollback of environmental regulations. A legal decision from 2009 asserted that greenhouse gases like carbon dioxide and methane are contributing to global warming, posing risks to public health and safety. This decision is crucial for the EPA’s ability to regulate greenhouse gas emissions under the Clean Air Act.

Dr. John Balmes, a spokesperson for the American Lung Association and a professor at the University of California San Francisco School of Medicine, expressed that this new study could serve as a “counterargument” against such actions.

The proposal to withdraw these findings is currently undergoing a lengthy regulatory process that is open to public commentary. Balmes mentioned that he referenced the study in a letter opposing the EPA’s proposed changes.

“It reinforces our claims regarding wildfires tied to climate change and their associated public health consequences,” Balmes stated.

On Wednesday, the National Academy of Sciences, Engineering, and Medicine released a report confirming that human-induced global warming is causing harm and will continue to do so in the future. The evidence is “extremely beyond scientific conflict,” asserted the committee behind the report.

The White House did not respond to requests for comments. The EPA stated that the administration is “committed to reducing the risks of catastrophic wildfires,” prioritizing strategies such as prescribed burns, fuel treatment, and debris cleanup to prevent these events.

“The EPA welcomes all public feedback on its proposal to rescind the 2009 danger findings until September 22, 2025, and looks forward to hearing diverse perspectives on this matter,” a spokesperson noted in an email.

In a novel study, researchers estimated the annual excess deaths attributed to wildfire smoke by comparing three models: one that assesses climate change’s impact on fire activity, another predicting changes in fire activity and smoke dispersion, and a third quantifying health outcomes from prolonged smoke exposure.

Researchers used data from 2011-2020 as a baseline to forecast future conditions under various climate scenarios, utilizing datasets that included all U.S. deaths within that period, both satellite and ground-level data on smoke dispersion, and global climate models.

The study assumes that people will take similar protective measures against smoke exposure as they do today.

This study has its limitations, as it primarily relies on a set of models to draw national conclusions. It does not track individual deaths linked to smoke exposure or catalog their health effects.

Results from this study were published alongside another study in Nature that employed a similar methodology and adopted a global perspective. Separate research teams estimate that premature deaths due to wildfire smoke could reach about 1.4 million annually by century’s end—approximately six times the current figure.