Once upon a time, fields of snow kept ground wet in the woods for a long time. Fast forward to today: Snow is melting earlier -- in early spring in some areas so the leaf-covered ground and fallen branches and surrounding brush dry out. The forest becomes parched. It's like a tinderbox. In summer, lighting crackles in the sky. A bolt strikes bone-dry grass, sparking a flame. High winds blow through, fanning the flame. A wildfire begins to rage.
What is a wildfire? Also called a "forest fire" or "brush fire," it's a fire that spreads quickly wildly -- in grasslands, forests or brush.
Nearly every month of the year, a wildfire burns somewhere in the US. It makes big news when it threatens lives and buildings, as regularly occurs each summer in the western US. Some put part of the blame for forest fires on the U.S. Forest Service's 100-year history of reflexively putting out blazes instead of allowing nature to go its course; the result has been a buildup of brush and spindly trees that easily catch fire. "Uncontrollable wildfire should be seen as a failure of land management and public policy," the National Commission on Wildfire Disasters warned in 1994. (See: http://seattlepi.nwsource.com/local/fire233.shtml)
There's a new wrinkle.
Warmer temperatures appear to be increasing the length and intensity of the wildfire season in the western US. One study found that the active wildfire season there has grown by 78 days, and on average a large fire burns 37.1 days, up from 7.5 days. "Since 1986, longer, warmer summers have resulted in a fourfold increase of major wildfires and a sixfold increase in the area of forest burned, compared to the period from 1970 to 1986," according to the journal Science. (See: http://www.sciencemag.org/cgi/content/full/313/5789/927).
While no weather event can be tied definitively to the changing climate, it is not incorrect to read certain weather events of harbingers of things to come, particularly when it comes to the intense wildfires ravaging California, Florida and other states. Scientists believe wildfires will become more intense as the US climate continues to react to the buildup of greenhouse gases in the atmosphere.
For more info:
* Expect more intense wildfires in a warming world: www.thedailygreen.com/2007/05/11/gavin-schmidt-the-week-in-weather
* Fighting wildfires before they start: http://science.nasa.gov/headlines/y2001/ast28aug_1.htm
* Is global warming causing more, larger fires?: www.sciencemag.org/cgi/content/full/313/5789/927
* Warming climate fuels mega-fires: www.cbsnews.com/stories/2007/10/18/60minutes/main3380176.shtml
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