In an open-access report in the journal Environmental Pollution, researchers from UCLA and the University of Chicago estimate that California’s wildfire carbon dioxide equivalent (CO2e) emissions from 2020 (~127 mmt CO2e ) are approximately two times higher than California’s total greenhouse gas (GHG) emission reductions since 2003.
Without considering future vegetation regrowth, CO2e emissions from the 2020 wildfires could be the second most important source in the state above either industry or electrical power generation.
Annual emissions from individual sectors and wildfire emissions. CARB, GFAS, and GFED wildfire emissions shown as red lines (not considering vegetation regrowth). Jerrett et al.
The carbon dioxide from wildfires is not counted against California’s emissions targets. But if it were, the wildfires would be setting California back in meeting its climate goals, with the carbon emissions from California’s 2020 fire season alone making up 49% of the state’s 2030 emissions target.
“To the great credit of California’s policy-makers and residents, from 2003 to 2019, California’s GHG emissions declined by 65 million metric tons of pollutants, a 13 percent drop that was largely driven by reductions from the electric power generation sector,” said Michael Jerrett, UCLA Fielding School of Public Health professor of environmental health sciences and an author of the study. “Essentially, the positive impact of all that hard work over almost two decades is at risk of being swept aside by the smoke produced in a single year of record-breaking wildfires.”
California’s expansive wildfires were the second largest source of emissions in the state in 2020, behind only the transportation sector. While some of the carbon release from fires will be balanced by later vegetation regrowth, it will not occur quickly enough to avert highly dangerous levels of increased emissions, temperatures, and climate change, the researchers said.
Although wildfires are a natural feature of many ecosystems in California, the increase in severe and frequent wildfire events has raised the possibility of transformed post-fire ecosystems. Even if long-term regrowth occurs, however, the carbon emissions occurring in the next 15–20 years will make it difficult to reach emission reduction targets needed to avert the increases in mean global temperature advocated by the Intergovernmental Panel on Climate Change, or IPCC.—Dr. Miriam Marlier, a UCLA Fielding School professor and co-author
The researchers also examined the financial costs. The carbon emissions released from the 2020 wildfires equate to more than $7 billion in total global damages, or about $986.9 million in damages to the United States and some $98.7 million in damages for California. These damages are on top of the fire control costs, damages from air pollution, and direct loss of life and property.
The findings imply several research directions and policy actions. The externalities caused by fire emissions incurs damages globally and in California, and the economic value should be considered alongside other direct costs of fires, including prevention and suppression. Wildfire emissions are not routinely reported with other key emission sources such as transportation, industry, and power generation. While wildfire emissions tend to be more variable than other sectors, it is still important to track these emissions to ensure near and medium-term emission reduction targets are met.
A likely consequence is that wildfire emissions have not received nearly the same level of societal investment or attention as emissions from other sectors. Although wildfires are to some extent natural occurrences, human activity contributes to making wildfires “unnatural disasters” through anthropogenic climate change and development at the WUI in fire prone areas. Moreover, forest management policies focused on fire suppression rather than on preventive measures such as mechanical clearing and prescribed burning activities also likely increases the risk of large, destructive wildfires. If fires are no longer in balance with ecosystem regrowth, we risk different vegetation communities regrowing with less potential for carbon sequestration.
A need also exists to develop accessible quantitative tools for policymakers and the public to understand how wildfire risk can be reduced through better management, how much loss of life and property can be avoided, and how much it will cost to achieve these goals. This will allow for more accurate assessment of investments in improved forest management or prevention of development in fire prone areas at the wildland-urban interface.—Jerrett et al.
Michael Jerrett, Amir S. Jina, Miriam E. Marlier (2022) “Up in smoke: California’s greenhouse gas reductions could be wiped out by 2020 wildfires,” Environmental Pollution, Volume 310, doi: 10.1016/j.envpol.2022.119888