Mankind has an effect on the number of wildfires, but not in the way many politicians or journalists would have you think, says a forestry professor.
Professor David B. South of Auburn University says that atmospheric carbon dioxide concentrations have nothing to do with the amount and size of wildfires. It’s largely forest management that determines the number and size of wildfires, not global warming.
“Policy makers who halt active forest management and kill ‘green’ harvesting jobs in favor of a ‘hands-off’ approach contribute to the buildup of fuels in the forest,” South told the Senate Environment and Public Works Committee on Tuesday.
“This eventually increases the risk of catastrophic wildfires,” South said. “To attribute this human-caused increase in fire risk to carbon dioxide emissions is simply unscientific.”
Government wildfire data shows that the scale of U.S. wildfires have decreased dramatically since 1930, when wildfires burned more than four times the amount of acreage burned in 2012. In 1930, wildfires consumed more than 50 million acres of land, but in 2012 wildfires only burnt up 9.2 million acres.
According to the National Oceanic and Atmospheric Administration (NOAA), carbon dioxide concentrations were much lower in the 1940s (only 310 parts per million by volume), meaning global temperatures were cooler while wildfires were much more prevalent than today.
“These data suggest that extremely large megafires were 4-times more common before 1940,” South said, adding that “we cannot reasonably say that anthropogenic global warming causes extremely large wildfires.”
“However, in today’s world of climate alarmism, where accuracy doesn’t matter, I am not at all surprised to see many journalists spreading the idea that carbon emissions cause large wildfires,” South said.
But while wildfires have become much less prevalent since the 1930s and 1940s, the media often reports that wildfires are on the rise, essentially cherry-picking data. From 1985 to 2013, there is a slight increase in the acreage being burnt by wildfires, making it seem as if rapidly rising carbon dioxide levels are to blame — since atmospheric concentrations are now around 400 parts per million by volume.
But this is not the case, says South, as the recent increase in wildfires has more to do with environmentalists forcing the U.S. to change its forestry policies than it has to do with carbon dioxide.
Environmentalists have convince public lands regulators to take a more hands off approach to forestry, meaning they are doing little to make sure the “fuel load” on federal lands and forests are at manageable levels — meaning the amount of dry, combustible organic materials on federal lands is increasing.
“The risk of wildfires since 1977 has increased on federal lands, in part, because of an increase in the ‘fuel load’,” South said. “This increase is due to tree growth plus a reduction in harvesting logs for wood products.”
Wildfires in California have been especially susceptible to increasing fuel loads. In just on decade, fuel loads on California timber land went up 16 percent while the average size of wildfires increased by 32 percent.
What’s the answer to reducing fuel loads? Clearing forests, conducting controlled burns and other policies, suggests South.
“They can reduce ladder and crown fuels by harvesting trees and transporting the logs to a mill,” South said. “This can be accomplished as final harvests, economic thinnings, firebreak thinnings and biomass thinnings.”
“Surface fuels can be reduced by conducting prescribed burns (a.k.a. controlled burns),” South added. “However, in the past policy has been determined by concerns expressed by journalists and activists who are against the cutting of trees. Many ‘preserve the forest’ and ‘anti-forest management’ policies end up increasing the risk of intense wildfires.”