WildfiresThe Shifting Burden of Wildfires in the United States

Published 1 February 2021

Wildfire smoke will be one of the most widely felt health impacts of climate change throughout the country, but U.S. clean air regulations are not equipped to deal with it. Experts discuss the causes and impacts of wildfire activity and its rapid acceleration in the American west.

Record-setting wildfires torched huge swaths of western states in 2020. They blotted out the sun, produced hazardous air pollution in cities far from the blazes and sent toxic smoke wafting clear across the country and beyond. Such far-reaching effects are no longer aberrations, Stanford scholars write in research published Jan. 12 in Proceedings of the National Academy of Sciences.

The number of homes at direct risk from wildfires – and the investment in firefighting resources to protect them – is on the rise. Nearly 50 million homes in the U.S. now sit in the wildland-urban interface where houses are close to forests and highly combustible vegetation, according to the authors, led by Marshall Burke, an associate professor of Earth system science in Stanford’s School of Earth, Energy & Environmental Sciences (Stanford Earth).

Moreover, being in close proximity to trees, brush and wilderness is no longer a prerequisite for suffering impacts from wildfire. Burke and colleagues estimate that wildfires have accounted nationwide for a quarter of the toxic fine particle pollution known as PM2.5, up from 10 percent a decade ago, and up to half of that pollution in parts of the American West. “Climate change is a primary driver of these changes,” said Burke, “and this particular climate impact is one we need to pay a lot more attention to.”

In an interview with Josie Garthwaite of Stanford News, Burke and co-author Michael Wara, director of the Climate and Energy Policy Program at the Stanford Woods Institute for the Environment, discuss the growing risk and shifting burden of wildfires in the United States.

Josie Garthwaite: Rising sea levels, worsening droughts, more frequent hurricanes and hotter temperatures are among the effects of climate change we often hear about impacting people. How does wildfire smoke compare to those threats?
Marshall Burke
: For many people in the western U.S., increases in wildfire risk due to climate change are, along with the direct effect of extreme temperatures, going to be the main climate impact that people experience – much more than sea level rise or hurricanes. This is mainly due to the worsening air quality that most of the U.S.– and particularly the western U.S.– will likely experience as the climate warms and large fires become more frequent. This particular climate impact is one we need to pay a lot more attention to.