Wildfire smoke could kill 70,000 Americans annually by 2050. Stanford researchers warn it may become the deadliest climate threat, with health costs surpassing all other climate damages in the United States.
Wildfire smoke is rapidly emerging as one of the deadliest consequences of climate change, threatening to claim up to 70,000 American lives annually by mid-century. A new study from Stanford University, published in Nature, warns that the health costs of smoke pollution could outweigh all other climate damages in the United States combined.
A Growing Health Crisis
Once seen as a seasonal nuisance in the West, wildfire smoke has now become a nationwide crisis. Warmer, drier conditions are fueling more frequent and larger fires, with smoke traveling across thousands of miles and lingering for weeks. Recent Canadian wildfires blanketed much of the Midwest and East Coast in thick haze—just one sign of how widespread the problem has become.
“There’s a broad understanding that wildfire smoke exposure is changing fast,” said Marshall Burke, senior author of the study and professor at Stanford’s Doerr School of Sustainability. “Our work puts hard numbers on what that means for public health now and in the future.”
The Hidden Toll of Smoke
Wildfire smoke contains a complex mix of toxic particles and gases. Among them, fine particulate matter (PM2.5) is especially dangerous because it penetrates deep into the lungs and bloodstream. Long-term exposure is linked to asthma, heart disease, and premature death.
By analyzing U.S. death records from 2006 to 2019 and combining them with climate and air quality data, the researchers estimate that smoke already contributes to about 40,000 deaths per year. Without major changes, that number could rise by 70% to around 70,000 annual deaths by 2050.
The economic impact is staggering: smoke-related deaths could cost the U.S. more than $600 billion per year—surpassing losses from storms, floods, and heat combined.
No Community Is Safe
The study found that every U.S. region will face higher risks, not just the fire-prone West. California is projected to see the steepest rise, with more than 5,000 additional smoke-related deaths each year. Large increases are also expected in New York, Pennsylvania, Texas, and Washington.
“Even if we cut global emissions and stabilize warming, deaths from wildfire smoke in the U.S. will likely exceed 60,000 annually by 2050,” said lead author Minghao Qiu, now at Stony Brook University.
Protecting Public Health
Researchers emphasize that action can still save lives. Communities can invest in better indoor air filtration, distribute masks during smoke events, and expand prescribed burns to reduce fuel loads in forests. But without addressing climate change, experts warn, these measures will only blunt part of the problem.
“Our understanding of who is vulnerable is broader than we thought,” Burke added. “It’s pregnant women, kids in schools, people with asthma, cancer patients—really anyone. This is not a localized issue, it’s a shared national burden.”
A Warning for Policymakers
Despite its enormous toll, wildfire smoke is still overlooked in many climate risk assessments. The Stanford team argues that policymakers must recognize smoke as a central climate threat, not a side effect.
“This study shows that ignoring wildfire smoke is like leaving the main character out of a movie,” Qiu said.
As fires grow larger and smoke spreads farther, America is confronting a climate-driven public health crisis that no one can escape. Without bold action, the air itself may become one of the deadliest legacies of climate change.