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November 2007
The recent wildfires in southern California are the most recent example of global warming making a bad situation much much worse. If there's a message to take home from this tragedy, it's that we are woefully unprepared for the type of catastrophes we expect to see more and more of with global warming.
- With temperatures in the West rising, the likelihood of forest fires also increases. According to Tom Swetnam, the Director of the Laboratory of Tree-Ring Research & Professor of Dendrochronology at the University of Arizona, that temperature rise has resulted in four times more fires. These findings were published by Swetnam and his colleagues in the journal "Science," and supported by climate change experts from around the globe.
- Interannual variability in wildfire frequency - the number of wildfires in a year - is strongly associated with regional spring and summer temperatures (Science 18 August, 2006). Warmer temperatures in the West affect summer rainfall levels and increase the likelihood of drought conditions. Thus, the flammability of fuels in forests, such as shrubs and pine needles, become even more prone to fires. Not only do higher temperatures have an adverse effect on the kindling for these fires, the temperature prompts earlier snowmelt in these high elevation areas. Snowmelt, the water runoff produced from the melting of the winter snow, is a significant factor in increased wildfire.
As the spring is arriving earlier because of warming conditions, the snow on these high mountain areas is melting and running off. So the logs and the branches and the tree needles all can dry out more quickly and have a longer time period to be dry. And so there's a longer time period and opportunity for fires to start."
-Tom Swetnam, CBS 60 Minutes interview
- Higher temperatures are drying out an already dry region thanks in large part to the lack of and early timing of the snowmelts creates a dangerous combination. This combination leads to more frequent and larger wildfires.
- The incidence of large wildfires in western forests started to increase in the mid-1980s. Subsequently, wildfire frequency is nearly four times what it was in the period between 1970 to 1986, and the total area burned by these fires was more than six and a half times its previous level (Science 18 August, 2006).
- The greatest increase in wildfire frequency has been in the Northern Rockies, which account for 60% of the increase in large fires. Much of the remaining increase (18%) occurred in the Sierra Nevada, southern Cascades, and Coast Ranges of northern California and southern Oregon ("Northern California," in fig. S2). The Pacific Southwest; the Southern Rockies; the Northwest; coastal, central, and southern California; and the Black Hills each account for 11%, 5%, 5%, <1%, and <1%, respectively.
- The Northern Rockies and the Southwest show the same trend in wildfire frequency relative to their respective forested areas. However, the Southwest's absolute contribution to the western regional total is limited by its smaller forested area relative to higher latitudes.
-Science [date]
- For years, instead of working to protect vulnerable communities like those in Southern California, the Forest Service has spent its time and money helping logging companies build roads and cut down large, fire-resistant trees deep in the backcountry--far away from homes and neighborhoods threatened by wildfire.
- The agency has steadily shifted its budget from fire prevention to subsidizing timber sales. Since the 2001 fiscal year, federal funding for state and local community fire protection programs declined from over $148 million to $85 million proposed in fiscal 2008. And by our calculations, the Forest Service would need to spend more like $2 billion a year to adequately protect communities from fire.
- In 2006, the Forest Service spent $2 billion last year fighting fires once they began-seven times more than was spent a decade ago.
Even with climate change working against us, there are measures we can take to combat these dangerous conditions. First, these fires underscore the need to focus fire prevention efforts where they matter the most-around communities.
If we want to prevent more of the kind of devastating fires we saw in California this fall, we need to focus our energy and money on making communities safer, figuring out how to best respond to large-scale disasters like this, and combating global warming by promoting clean renewable energy, energy efficiency programs and making our cars go farther on a gallon of gas.
Photo courtesy Chuck Pezeshki/Sierra Club Collection; all rights reserved.
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