“An interesting and counterintuitive paper finds that wildfires in the western United States might actually improve air quality in the east thanks to the heat they generate, which blocks smoke from drifting and creates more rainfall that washes pollution out of the air,” notes The Doomslayer.
Science reports:
One could be excused for assuming that wildfires in the western US worsen air quality across the rest of the nation only due to smoke transport, but that would be incorrect. Instead, Ma et al. showed that extreme wildfires in the west actually reduce fine particle concentrations in the eastern US by an amount comparable to the increases that they cause in the west…They attributed this unexpected effect to weakened eastward transport of fire smoke and enhanced wet removal of air pollutants caused by heat-induced convection from fires. This mechanism actually reduces deaths and economic losses nationwide….
Conventional wisdom suggests that wildfires in the western United States (WUS) degrade air quality nationwide as a result of aerosol emissions and eastward transport. However, we found that heat produced by wildfires, a commonly neglected effect, can reduce fine particle concentrations (PM2.5) in the eastern United States (EUS) by an amount comparable to the increases in the WUS during the fire season. This phenomenon arises from fire heat–induced convection in the WUS and subsequent downstream meteorological changes distant from fires. Enhanced wet deposition and weakened eastward transport of fire aerosols lower PM2.5 levels in the EUS. Therefore, neglecting the effect of fire heat on PM2.5 pollution leads to an overestimate of 1200 additional premature deaths and 3.3 billion USD in economic losses, particularly in the densely populated EUS.
This paper deals with air pollutants (things that make the air dirty), not global warming. Even if wildfires don’t make the air dirtier in the east, they can still contribute to global warming by triggering more greenhouse gas emissions. California has lots of wildfires due to state policies that make it harder to prevent wildfires (such as policies that prevent controlled burns and result in the buildup of more flammable brush). A UCLA study found that California’s wildfire emissions of greenhouse gases in 2020 were twice the total greenhouse-gas reductions the state achieved from 2003 to 2019. Decades of Californian climate change advocacy has, quite literally, gone up in smoke.”
In the southeast, unlike California, states do a sufficient amount of controlled burns to get rid of flammable material, and keep wildfires from raging out of control. As NPR explained in 2021, in
the Southeastern U.S….prescribed fire is widespread thanks to policies put in place decades ago. From 1998 to 2018, 70% of all controlled burning in the country was in the Southeast….For thousands of years, forests and woodlands experienced regular burning, both sparked by lightning and used by Native American tribes, which prevented the buildup of flammable growth. Without [such fires], the landscape is prone to intense, potentially devastating wildfires….
By the 1960s, land managers realized that many landscapes had become choked with brush, grasses and small trees. In the Southeast, where the majority of land is privately owned…residents had continued controlled burning [to get rid of flammable brush]…..
Florida has done prescribed burns on more than 1.6 million acres so far this year. California has only burned around 35,000 acres. The state is 2.5 times larger than Florida….
Experts estimate that tens of millions of acres [in California] need addressing statewide, but lack of funding, personnel and political will has limited the work on public lands….[California] landowners have had little support from public agencies to conduct burns on their property. Permits from firefighting agencies and air quality regulators can be cumbersome to secure…
“California is, in some ways, in the dark ages with prescribed fire,” [Director of Fire Research Morgan] Varner says.
