The Nature study of Canada’s boreal forest turning from carbon sink to carbon source is less uncertain than the numbers on the California fires. But there are unanswered questions about where the effects of more fires in that region fit into the worldwide picture. The research team concludes that the shift is an indirect consequence of global warming, but the CanWest News Service quotes the lead author saying that he is “reluctant” to extrapolate the results to other parts of the boreal forest, outside the area studied.
Assessing the aggregate environmental impact of wildfires around the globe is incredibly complicated. Clouds of particulate matter, such as those produced by large burns, were once thought to have a net cooling effect, and only recently have scientific reports tipped toward warming. Yesterday’s San Diego Union-Tribune article - which, again, strangely does not mention either of the journal studies - does a good job of laying out the many variables in wildfire research. “As a source of pollutants linked to global air pollution and climate change,” the article concludes, “human activity is far more problematic than nature.”
As the media debate over whether global warming or the nefarious chaparral (dry California shrubbery) caused the California conflagration demonstrates, however, fires (and their ecology) are still poorly understood phenomena. Last year The New York Times reported on a National Academy of Sciences study that many forests in many nations (including the U.S.) are now growing back after a protracted decline during most of the twentieth century. So the question of whether forests are carbon sinks or sources over the long term is incredibly important, especially given current uncertainties in the politics of forest management. The timber industries in both the U.S. and Canada have been trying to insert themselves into the climate-change debate. This summer, a number of publications reported on the U.S. timber industry’s congressional lobbying to create a national carbon market under a cap-and-trade system. The forests it manages could serve as valuable, credit or offset earning sinks in the new market. In Canada this week, the timber industry announced it would be carbon neutral by 2015.
As winter sets in and the embers in southern California slowly burn out, it is likely that public and press attention will drift away from the forest management and wildfire ecology story. But there are plenty of opportunities for more reporting, even during the wet months, and things to be learned before the next blaze.