Wildfires are projected to increase dramatically due to climate change. That could trigger a massive increase in heart attacks, premature births and early deaths, research reveals.
When you purchase through links on our site, we may earn an affiliate commission. Here’s how it works.
As wildfires raged through Ontario, Canada in mid-July, millions of people in the Midwest and on the East Coast found themselves under a shroud of yellow skies, darkened by smoke from the infernos. The air quality index in Grand Rapids, Michigan hit 616 on July 16, breaking the previous record for the city of 350; any number over 301 indicates hazardous, emergency conditions.
Smoke events like this are only likely to worsen in the coming decades: Wildfires are one of the most imminent impacts of climate change.
Not only do the flames themselves directly threaten lives, but the smoke can trigger heart attacks, asthma attacks and premature births, as well as worsen heart disease or lung ailments such as chronic obstructive pulmonary disease (COPD). And those effects can spread as insidiously as smoke travels.
Smoke from wildland fires pours eastward over Canada and the U.S. in an image captured on the afternoon of July 14, 2026, by the VIIRS (Visible Infrared Imaging Radiometer Suite) on the NOAA-21 satellite.
A 2025 study found that the record-breaking 2023 Canadian wildfire season may have shortened the lives of 87,000 people exposed to the smoke plumes worldwide. Another 2025 study found that wildfire smoke contributed to 41,380 excess deaths per year in the U.S. between 2011 and 2020 and that the number will rise to 71,420 excess deaths by 2050 if global temperatures rise 5 to 8.3 degrees Fahrenheit (2.8 to 4.6 degrees Celsius) by the end of the century.
In North America, the health impacts of this extra fire are likely to be significant. Wildfire season is getting longer and more intense in the West and Southwest, while regions not historically prone to wildfires will need to deal with the impacts of smoke plumes that can travel thousands of miles.
"Wildfire smoke is the fastest-growing environmental threat [to health] in the U.S.," said Marshall Burke, a professor of global environmental policy at Stanford University who was the senior author of the study predicting the grim rise in excess deaths. "It's just changing so rapidly."
Even a rapid drop in greenhouse gas emissions wouldn't fully mitigate the growing risk of wildfires. Because these gases persist in the atmosphere for decades, a more fire-friendly future is already locked in.
"No one foresees changes in the near future, at least, that are going to result in decreases in wildfire," said Mary M. Johnson, a principal research scientist in environmental health at the Harvard T.H. Chan School of Public Health. Wildfires are "predicted to increase in size, intensity and frequency."
Global data suggests that without climate change mitigation, fires will increase in all vegetation types by the end of the 21st century. Even if warming is held to 2.2 F (1.5 C) over pre-industrial temperatures — an increasingly challenging goal to meet — fires outside of tropical latitudes will become more frequent.
In the U.S., the picture is bleak. Between 1984 and 2015, the number of large wildfires in the U.S. West doubled, according to the National Oceanic and Atmospheric Administration (NOAA). The seasonality of fire is also shifting. A February 2026 study published in the journal Geophysical Research Letters found that climate change is nudging fire season in the boreal forests of Alaska and Canada forward as winter snow vanishes earlier, leaving spring vegetation dry and ripe to burn. In the U.S. West, on the other hand, fire season is stretching later because of summer drought.
Smoke from Minnesota wildfires blanketed the Lincoln Memorial in Washington D.C. on July 17. Wildfire events can create huge smoke plumes that can travel thousands of miles, raising air pollution risks far from the fires themselves.
"It's about dryness," GRL study senior author Hongliang Zhang, an air quality researcher at China's Fudan University, told Live Science.
