| WASHINGTON, April 23
WASHINGTON, April 23 In a vicious cycle made
worse by humans, scientists now believe fires spur climate
change, which in turn makes blazes bigger, more frequent and
more damaging to the environment.
Climate experts have known that a warmer world would spawn
more fires, but in research published on Thursday in the
journal Science, scientists reported that fires -- especially
those set by humans to clear forests -- influence climate
Smoke particles sent into the atmosphere by fires inhibit
rainfall, which makes the land drier and encourages more fires
to start, said study co-author Jennifer Balch of the University
of Santa Barbara in California.
On a global scale, burning releases vast amounts of
heat-trapping greenhouse gases like carbon dioxide, making
fires more likely in a warming world, Balch said in a video
The report's authors estimate that greenhouse emissions
from the world's fires equal about 50 percent of emissions that
come from the burning of fossil fuels.
Deforestation fires, like those set to clear forest for
pasture in tropical areas like the Amazon, are part of an
unintentional "extreme experiment," Balch said: "We're testing
how burning forests will influence the climate system."
'THE SCARY BIT'
These deliberately set forest fires contributed up to
one-fifth of all human-generated warming in industrial times,
The climate-fire cycle works like this: plants store the
climate-warming gas carbon dioxide; when they burn, they
release the gas into the atmosphere, which contributes to
The more fires, the more carbon dioxide is released, which
in turn causes more warming in a cycle scientists call positive
"The scary bit is that, because of the feedbacks and other
uncertainties, we could be way underestimating the role of fire
in driving future climate change," said co-author Thomas
Swetnam of the University of Arizona in Tucson.
This important piece of the climate change puzzle has not
previously been emphasized, said co-author David Bowman of the
University of Tasmania in Hobart, Australia.
Most climate scientists considered fire to be a natural
disturbance that was not a crucial force that should be
considered in creating models of how the planet's climate will
change, Bowman said.
"Humans and fire have a complex and ancient relationship,"
Bowman said. "The relationship means that we can manage fire
but we can also start fires. A citizen can't create hurricanes,
but a citizen (who sets a fire) can create a mass disaster."
The report's 22 authors called on the U.N.
Intergovernmental Panel on Climate Change to take the role of
fire into account when making future climate models.