US fires release large amounts of carb...( BOULDER--Large-scale fires in a west...)

BOULDER--Large-scale fires in a western or southeastern state can pump as much carbon dioxide into the atmosphere in a few weeks as the state's entire motor vehicle traffic does in a year, according to newly published research by scientists at the National Center for Atmospheric Research (NCAR) and the University of Colorado at Boulder.

The paper, "Estimates of CO2 from fires in the United States: implications for carbon management," is being published online today in the journal "Carbon Balance and Management." NCAR's portion of the research was supported by the National Science Foundation, NCAR's principal sponsor.

The authors, Christine Wiedinmyer of NCAR and Jason Neff of the University of Colorado, used satellite observations of fires and a new computer model, developed by Wiedinmyer, that estimates carbon dioxide emissions based on the mass of vegetation burned. They caution that their estimates have a margin of error of about 50 percent, both because of inexact data about the extent of fires and varying estimates of the amount of carbon dioxide emitted by different types of blazes.

Overall, the study estimates that fires in the contiguous United States and Alaska release about 290 million metric tons of carbon dioxide a year, which is the equivalent of 4 to 6 percent of the nation's carbon dioxide emissions from fossil fuel burning. But 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.