After dodging two waves of catastrophic wildfires in four years,
surely we don't have to worry about another one invading our
neighborhoods for a while, right?
Not so fast.
Some climate experts say last month's enormous, wind-driven
infernos, which torched 368,000 acres and destroyed 1,751 homes and
businesses in San Diego County alone, could become a regular
feature of life in Southern California.
"There is more to come, unfortunately," said Thomas Swetnam,
director of the University of Arizona's Laboratory of Tree-Ring
Research, in a telephone interview last week.
We may be able to thank global warming for that.
As our skies fill with a thickening blanket of greenhouse gases,
such as carbon dioxide from the cars we drive and the power plants
that churn our air conditioners, Southern California is destined to
get hotter and drier, according to some scientists. Others contest
that finding, saying climate is too complex of a system to bear all
the blame for single events such as wildfires.
But one recent study suggests Santa Ana winds will blow more
often, increasing the likelihood of massive out-of-control
"There is a potential for the Southwest to more or less enter a
permanent dust bowl situation," Swetnam said. "The extended drought
that we are in now may become the norm."
Hot, dry, windy
Southern California is in store for "a big, heavy drying spell,"
said Norm Miller, a climate scientist at UC Berkeley's Lawrence
Berkeley National Laboratory. Miller is a member of the
Intergovernmental Panel on Climate Change, which published several
global warming reports and shared the Nobel Peace Prize with Al
Gore this year.
Miller said 19 of 23 climate models scientists developed for
California suggest many future storms will veer north, showering
Seattle with more rain than it receives now and causing less to
fall between Sacramento and the border.
And, he said, "we're seeing more heat waves in Southern
California. They're just going off the charts."
Making matters worse, Miller said, the hotter and drier
conditions are likely to be accompanied by more episodes of
hurricane-force Santa Ana winds that peak around Thanksgiving,
rather than at the end of October.
Miller and Nicole Schlegel, a scientist at UC Berkeley's
Department of Earth and Planetary Science, highlighted the
increased Santa Ana threat in a study published in August 2006 in
the Geophysical Research Letters, a monthly publication of the
American Geophysical Union. The University of Arizona's Swetnam
termed it the first significant peer-reviewed study linking climate
change with the future of wildfire in Southern California, although
one that has yet to be verified by other studies.
Miller said more wind not only could mean more fires overall,
but more mammoth ones like those that ravaged five Southern
California counties last month.
A place of fire
But some scientists say it is not a foregone conclusion that
megafires will flare up more often.
Tony Westerling, a UC Merced professor of environmental
engineering and principal investigator for the California Climate
Change Center at UC San Diego's Scripps Institution of
Oceanography, said that is because the fires of the future will
depend on many factors, not just warming.