The recent horrific fires in California have reignited a debate on the role that supposed man-made warming has on these events. Governor Jerry Brown leads the way, stating, “This is the new abnormal, and this new abnormal will continue, certainly in the next 10, 15, 20 years. Unfortunately, the best science is telling us that dryness, warmth, drought, all those things, they’re going to intensify.” Is he correct?
The answer is much more complicated than Gov. Brown’s. Human activities and government policies have played an outsized role in many of the fires across the western United States, including the Golden State.
Contrary to most public pronouncements, wildfires across the northern hemisphere have been in long-term decline and California is no exception. According to University of Washington climate scientist Cliff Mass, the number of fires in the state has been in a decades-long decline. In fact, Mass reports, the number of fires over the 30-year period from 1987 to 2016 has declined by about 50% while during the same period the area burned has increased slightly. That means that each fire has roughly doubled in size.
Confirming the decline in incidence of California fires is United State Geological Survey (USGS) fire scientist Jon Keeley who looked at data going back to 1920 and found that the number peaked during the 1970s with a significant decrease since.
The first ingredient of fires is an ignition source. According to Keeley, 95% of the fires are caused by humans. Specific igniters include electric utility lines, vehicles, smoking, arson and motorized equipment like lawn mowers or weedwackers. With more homes encroaching into fire prone areas, it stands to reason that human-caused ignition would increase. According to Keeley, the number of homes at risk in the western United States has increased from 607,000 in 1940 to 6.7 million in 2010, greatly expanding the presence of human igniters.
A second primary ingredient for wildfire is fuel. Once again, we find a significant and dangerous human imprint on the fuel available for fires across the western United States. Review of photos from the period just after Gold Rush show a Sierra landscape that had large open fields of grass with stands of oak and pine. Notably, the first branches on the pines started 20 feet or more from the ground owing to low intensity grass fires that Native American encouraged to benefit game animals.
In the early to mid-20th century, sensible forest management included periodic timber harvests, tree thinning, controlled burns and grazing. Beginning in the 1960s and accelerating under the Clinton Administration’s 1994 plan for “naturally functioning ecosystems,” the government strictly limited logging and accelerated fire suppression to protect old growth forests and spotted owls. In an interview with Evergreen magazine that year Bob Zybach, a forester with a Ph.D. in environmental science, warned that dead and dying material accumulating in forests of the west along with the decision to put out wildfires would lead to “wildfires reminiscent of the Tillamook Burn, the 1910 fires, and the Yellowstone fire. I don’t think the public is willing to accept the loss of life and the loss of forests associated with fires this big.”
According to the Sierra Nevada Conservancy, hardly a pro-logging group, there are currently 300 to 400 trees per acre instead of the historical number of 50 to 80. This dense growth promotes the spread of bark beetles that leads to tree deaths and kindling waiting for a spark to rage into an inferno. “Fires that once revitalized forests are instead destroying them, resulting in massive amounts of dead trees,” says the conservancy.
The final ingredient necessary for extensive wildfires is arid conditions and much of California has been in the grip of a years-long drought. One of the primary causes of soil moisture loss, second to extreme heat, is water loss through the transpiration process of plants. With five times as many trees per acre, each additional tree is competing for the already scarce water in the soil, leading to even drier conditions.
Californians are suffering not from Gov. Brown’s “new abnormal” but from ill-conceived policies of radical environmental groups and anti-logging activists who planted a time bomb that is now exploding.
This is confusing. Are these all one fire, three different fires in three different places, three different times or what? You should say something about their magnitude, loss life, property damage.