Scientists predict that wildfire smoke is responsible for tens of thousands of deaths each year and will do more harm to U.S. residents by midcentury than any other threat driven by climate change, including extreme heat. According to the new research report, each year, on average, wildfire smoke is causing more than 41,400 excess deaths, or more than would be normally expected without smoke, given the demographics of the U.S. That figure is more than twice what was previously recognised in other studies.
By midcentury, the study’s authors expect that number to grow by an additional 26,500 to 30,000 deaths as human-caused climate change worsens and the risk of wildfires igniting increases. A growing body of research suggests wildfire smoke exposure causes significant health problems. Small particles in wildfire smoke penetrate into the lungs and can circulate in the bloodstream. Smoke can increase risk for asthma, lung cancer and other chronic lung problems.
Wildfire smoke is also associated with preterm birth and miscarriage. The study offers a stark vision of an increasingly smoke-choked nation. Decades of work to clean up industrial U.S. air pollution through the Clean Air Act are being undone as fires in the western United States and Canada send plumes of smoke into the atmosphere that then spread across the landscape.
The study suggests the death toll of wildfire smoke will increase by 64% to 73%, or more, by midcentury, depending on the rate of emissions. The Environmental Protection Agency is trying to rescind a key legal provision known as the “endangerment finding” as part of a broad rollback on environmental regulations.
This 2009 legal decision says greenhouse gases like carbon dioxide and methane are warming the Earth and that warming presents a threat to public health and welfare. In the Nature study, researchers estimated the number of excess deaths from wildfire smoke each year by comparing three models: one that estimates the influence of climate change on overall fire activity, another that models expected changes in fire activity and where smoke will travel, and a third that quantifies health outcomes that result from long-term smoke exposure.
The researchers used 2011-2020 as their baseline and predicted future conditions under several climate scenarios. They had access to every U.S. death during that period, satellite and ground-level data about smoke travel, and global climate models, among other data sets. The study assumes that people would take the same steps to avoid smoke exposure as they do today.
