Expert: Global warming fueling 'mega-fires'
Global warming is partly to blame for the increasing intensity and frequency of massive wildfires in the American West, according to one expert, who says more than half of the region's forests could be claimed by fire in the next century.
Tom Swetnam, a leading fire ecologist at the University of Arizona, told CBS's 60 Minutes that a temperature increase in the West of just one degree had contributed to a four-fold increase in fires in the area.
"The fire season in the last 15 years or so has increased more than two months over the whole Western US," Swetnam said. "So actually 78 days of average longer fire season in the last 15 years compared to the previous 15 or 20 years."
The warmer temperature, he said, had created ideal conditions for fires to take hold on the forest floor.
"As the spring is arriving earlier because of warming conditions, the snow on these high mountain areas is melting and running off," he said. "So the logs and the branches and the tree needles all can dry out more quickly and have a longer time period to be dry. And so there's a longer time period and opportunity for fires to start."
Tom Boatner, the federal government's chief of fire operations -- who has fought fires in the region for 30 years -- told the program that he was seeing the effects of global warming first-hand.
"This kind of low brush would normally be really moist and actually be a fairly good barrier to fire," Boatner told 60 Minutes' Scott Pelley. "But as I look at this I just see wilted leaves everywhere. There's no moisture left in them. They're dead."
Asked about skeptics who question the existence of climate change, Boatner said they didn't include his colleagues.
"You won't find them on the fire line in the American West anymore," he said. "Because we've had climate change beat into us over the last ten or fifteen years. We know what we’re seeing."
Swetnam said the increasing likelihood and damage potential of the fires could have sweeping consequences for ecosystems in the West.
"We're seeing century-old forests that had never sustained these kinds of fires before, being razed to the ground," he said. "As fires continue to burn, these mega-fires continue to burn, we may see ultimately a majority, maybe more than half of the forest land converting to other forest, other types of ecosystems."
Asked whether that meant there was a "reasonable chance" that half the forests could be lost, Swetnam said it was a possibility.
"Yes," he said, "Within some decades to a century as warming continues, and we continue to get large scale fires."
This video is from CBS's 60 Minutes, broadcast on Dec. 30, 2007.