Raging wildfires driven by powerful winds forced the evacuation of hundreds of homes in Southern California in late October causing the destruction of 500 homes and 100 businesses. From San Diego to Malibu, fires ravaged more than 150 miles up the coast and precipitated the evacuation of some 300,000 people. President Bush declared a federal emergency for seven counties to speed up disaster-relief efforts. The wildfires claimed one life, in San Diego County, and injured 42.
Although wildfires have multiple causes, evidence is mounting that California and much of the American West will find such devastating wildfires more of a threat as the climate warms even a small amount. Seemingly small rises in average temperature may translate to sizable reductions in soil moisture. Just as these fires were raging CBS's 60 Minutes broadcast a segment on fires in the US West in which Tom Boatner, chief of operations for the US Government's fire fighting effort, made clear that he attributed the great upsurge in Western fires to climate change.
A few months earlier as about 300 scientists, governmental officials and concerned citizens gathered in Tampa for a three day climate conference May 9-11, 2007, the State of Florida found itself fighting over 230 wildfires, linked to a persistent drought that had created an ideal environment for the spread of wildfires, whether sparked by lightning, arson, careless campers, or smokers who discarded butts from their cars. By the third day of the Conference the skies over Tampa and many other areas of Florida were filled with smoke from fires in nearby areas. That week flights out of Tampa and Miami airports were delayed in taking off because of often thick smoke obscuring visibility. By Sunday May13 wildfires started the week before by lightning in the Okefenokee Swamp in Southeast Georgia had charred more than 233,700 acres in Georgia and Florida and generated enough smoke to cause authorities to close two highways until winds had dissipated the smoke.
Some conference participants undoubtedly wondered whether there was a link between these fires and the global warming trend that had gotten them aroused enough to spend three days in a Tampa hotel discussing ways Florida could respond to a threat of rising sea levels and changing climatic conditions. Similar questions likely have been raised by the general citizenry of Florida, California, Alaska, other Western states, Canada, Australia and Southern Europe, all of which have in some years experienced large-scale wildfire damage.
As scientists will point out, it is quite difficult to attribute any single fire, heat wave, flood, drought, or severe storm to climate change. This may be even more difficult in the case of wildfires that may be attributable initially to human negligence, lightning strikes or arson but with the spread of the fires abetted by drought conditions, winds and availability of fuel- sometimes a function of public policy.
Still, there is a growing consensus among scientific researchers that many parts of the world may experience a more severe wildfire risk as the global climate warms and that these risks may already be playing out in a huge increase in major wildfires in the Western United States since 1986. In the Siberian taiga, Canadian Rockies and Australia, researchers are starting to link an upsurge in wildfires to climate change. Perhaps the most spectacular of these fires have occurred in Australia, particularly during the 2006-2007 fire season. The Australian Government's widely respected scientific research organization, CSIRO, has projected increased wildfire risk for Australia as a consequence of climate change.
Since the 2003-2004 fire season, climate.org has prominently posted data on a potentially growing wildfire risk in the Western US and Alaska. On September 19, 2006, at the Washington Summit on Climate Stabilization, Dr. Eric Kasischke of the University of Maryland indicated that coincident with a recent warming trend in Alaska and Canada there has been a doubling of the annual burned areas in wildfires between the 1960s/1970s and the 1980s/1990s. He projects that the changed fire regime and likely climate change, including permafrost thaw, is very likely to result in a loss of coniferous forest and an increase in deciduous forests and grasslands.
A major study of climate change implications for California highlighted increased wildfire risk as a great challenge. Wildfires have been a major concern in Southern Europe; 2000 was a particularly devastating year. An interesting European study examines the fire trends in some detail. The study does not, however, address likely future risks under a climate change scenario. The Intergovernmental Panel on Climate Change in the IPCC Fourth Assessment projects increased wildfire risk in Southern Europe and North America as the climate warms. As research expands on wildfire risk, climate.org will seek to make the results accessible.
November 6, 2007
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