Science Sunday: Catch CO-2 — Carbon Dioxide from Fires

Forest fires can emit a lot of carbon into the atmosphere — but there may be little that can be done about it, thanks to Smokey Bear.Wildfires in the West and Southeast can compete with human fossil-fuel burning as a source of carbon dioxide in the atmosphere for the states in which they’re burning, according to a paper published this week online in the journal Carbon Balance and Management.

Christine Wiedinmyer of Boulder’s National Center for Atmospheric Research (NCAR) and Jason Neff of the University of Colorado found that fires in the 48 contiguous states and Alaska release about 290 million metric tons of carbon dioxide each year – an amount equivalent to four to six percent of total U.S. CO2 emissions.

Carbon dioxide is the gas most responsible for the current global atmospheric warming trend. The current CO2 concentration in the atmosphere is about 383 parts per million, which is about 38 percent above the pre-industrial levels of 284 ppm as measured in ice cores.

Smokey Bear has been telling us for years to prevent forest fires. This fire suppression policy has resulted in more forested areas. These trees take carbon from the atmosphere and store it, helping to reduce the overall contribution of CO2 into the atmosphere.

The Catch-22 in this scenario is that now there is heightened fire danger from the increased fuel load. And when those trees burn, they release much of that carbon they have been so conveniently storing.

The recent California fires, the authors report, released 7.9 million metric tons of CO2 in only a week – roughly the equivalent of all the fossil fuel burned in California in a week from cars, power plants and other sources.

“Enormous fires like this pump a large amount of carbon dioxide quickly into the atmosphere,” Wiedinmyer says. “This can complicate efforts to understand our carbon budget and ultimately fight global warming.”

Fires contribute a higher proportion of the potent greenhouse gas in several western and southeastern states, especially Alaska, Idaho, Oregon, Montana, Washington, Arkansas, Mississippi and Arizona. Particularly large fires can release enormous pulses of carbon dioxide rapidly into the atmosphere.

“A striking implication of very large wildfires is that a severe fire season lasting only one or two months can release as much carbon as the annual emissions from the entire transportation or energy sector of an individual state,” the authors write.