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Conservation Science for a Healthy Planet

In California’s wildfires, a looming threat to climate goals

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by Julie Cart December 14 2017 Read full CalMatters article here

Beyond the devastation and personal tragedy of the fires that have ravaged California in recent months,  another disaster looms: an alarming uptick in unhealthy air and the sudden release of the carbon dioxide that drives climate change.

…..The state’s environmental regulations are known to be stringent, but they have limits: They apply only to human-caused emissions. Carbon and other pollution generated by wildfires is outside the grasp of state law.

….In less than one week, for example, October’s wine-country fires discharged harmful emissions equal to that of every car, truck and big rig on the state’s roads in a year. The calculations from the subsequent fires in Southern California are not yet available, but given the duration and scope of the multiple blazes, the more recent complex of fires could well exceed that level.

The greenhouse gases released when forests burn not only do immediate harm, discharging carbon dioxide and other planet-warming gases, but also continue to inflict damage long after the fires are put out. In a state where emissions from nearly every industry are tightly regulated, if wildfires were treated like other carbon emitters, Mother Nature would be castigated, fined and shut down.

The air board estimates that between 2001 and 2010, wildfires generated approximately 120 million tons of carbon. But Clegern said a direct comparison with regulated emissions is difficult, in part because of limited monitoring data….

….Scientists estimate that in severely burned areas, only a fraction of a scorched tree’s emissions are released during the fire, perhaps as little as 15 percent. The bulk of greenhouse gases are released over months and years as the plant dies and decomposes.  And if a burned-out forest is replaced by chaparral or brush, that landscape loses more than 90 percent of its capacity to take in and retain carbon, according to the [Sierra Nevada] Conservancy….

….The role of wildfire as a major source of pollution was identified a decade ago, when a study conducted by the National Center for Atmospheric Research concluded 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 entire equation has been made worse by the state’s epidemic of tree death, caused by drought, disease and insect infestation. The U.S. Forest Service this week updated its estimate of dead trees across California to 129 million. That loss alone could be a blow to the state’s vision of a low-carbon future.

….Forests as carbon-chewers are part of the state’s strategy for cutting greenhouse-gas emissions significantly by 2020 and beyond—a goal that could be undermined by nature’s caprice. The air board will direct state agencies to determine more precisely how much carbon can be absorbed by California’s variety of landscapes….

….Sean Raffuse, an analyst at the Air Quality Research Center at the University of California, Davis, came up with the “back of the envelope” calculations for October’s Sonoma County fires.

Raffuse said he used federal emissions inventories from fires and calculated that five days of ashy spew from the northern California blazes equated to the annual air pollution from every vehicle in California….

 

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