WASHINGTON (AP) — The devastating wildfires scorching
Southern California offer a glimpse of a warmer and more fiery future,
according to scientists and federal and international reports.
In
the past three months, at least three different studies and reports have
warned that wildfires are getting bigger, that man-made climate change
is to blame, and it’s only going to get worse with more fires starting
earlier in the year. While scientists are reluctant to blame global
warming for any specific fire, they have been warning for years about
how it will lead to more fires and earlier fire seasons.
"The
fires in California and here in Arizona are a clear example of what
happens as the Earth warms, particularly as the West warms, and the
warming caused by humans is making fire season longer and longer with
each decade," said University of Arizona geoscientist Jonathan Overpeck.
"It’s certainly an example of what we’ll see more of in the future."
Since
1984, the area burned by the West’s largest wildfires — those of more
than 1,000 acres — have increased by about 87,700 acres a year,
according to an April study in the journal Geophysical Research Letters.
And the areas where fire has been increasing the most are areas where
drought has been worsening and "that certainly points to climate being a
major contributor," study main author Philip Dennison of the University
of Utah said Friday.
The top five years with the most acres
burned have all happened in the last decade, according to federal
records. From 2010-2013, about 6.4 million acres a year burned on
average; in the 1980s it was 2.9 million acres a year.
"We are going to see increased fire activity all across the West as the climate warms,"
Dennison said.
That
was one of a dozen "key messages" in the 841-page National Climate
Assessment released by the federal government earlier this month. It
mentioned wildfires 200 times.
"Increased warming, drought and
insect outbreaks, all caused by or linked to climate change have
increased wildfires and impacts to people and ecosystems in the
Southwest," the federal report said. "Fire models project more wildfire
and increased risks to communities across extensive areas."
Likewise,
the Nobel prize winning Intergovernmental Panel on Climate Change noted
in March that wildfires are on the rise in the western U.S., have
killed 103 Americans in 30 years, and will likely get worse.
The
immediate cause of the fires can be anything from lightning to arson;
the first of the San Diego area fires, which destroyed at least eight
houses, an 18-unit condominium complex and two businesses, seemed to
start from sparks from faulty construction equipment working on a graded
field, said California Department of Forestry and Fire Protection
spokeswoman Lynne Tolmachoff.
But the California fires are fueled
by three major ingredients: drought, heat and winds. California and
Arizona have had their hottest first four months of the year on record,
according to National Weather Service records.
Parts of Southern
California broke records Thursday, racing past 100 degrees. For the past
two weeks the entire state of California has been in a severe or worse
drought, up from 46 percent a year ago, according to the U.S. drought
monitor.
"With the drought this year, we’re certainly going to see
increased frequency of this type of event," Dennison said. "Because of
the drought the fuels (dry plants and trees) are very susceptible to
burning."
Another study last month in Geophysical Research Letters
linked the ongoing drought to man-made climate change. Other scientists
say that is not yet proven.
Scientists will have to do a lot of
time-consuming computer simulations before they can officially link the
drought to climate change. But Overpeck said what is clear is that it’s
not just a drought, but "a hot drought," which is more connected to
man-made warming.
The other factor is the unusual early season
Santa Ana winds, whose strength is a key factor in whipping the flames.
So far, scientists haven’t connected early Santa Ana to climate change,
Dennison said.
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Online:
The National Climate Assessment: http://www.globalchange.gov
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Seth Borenstein can be followed at http://twitter.com/borenbears
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