Climate change not seen increasing wildfires, study shows
Scenes of Californians fleeing their homes and Greeks swimming out to sea have fueled alarm about climate change fueling deadly wildfires, but recent studies show that such destructive blazes are on the decline worldwide.
A September 2017 report in the journal Science found that global burned area dropped by about 25 percent over the previous 18 years, a finding consistent with a May 2016 paper published by the Royal Society B: Biological Sciences.
″[G]lobal area burned appears to have overall declined over past decades, and there is increasing evidence that there is less fire in the global landscape today than centuries ago,” said the study by British researchers at Swansea University.
Even in California, which for years has wrestled with fire devastation, a study in the International Journal of Wildland Fire found that the number of wildfires burning more than 300 acres per year has been tailing off since a peak in 1980.
“The claim commonly made in research papers and the media that fire activity is increasing throughout the western USA is certainly an over-statement,” the authors, Jon E. Keeley and Alexandra D. Syphard, said in The Orange County Register.
Mr. Keeley is a scientist with the U.S. Geological Survey, and Ms. Syphard is with the Conservation Biology Institute.
Such findings appear to fly in the face of widespread reports that human-caused global warming is increasing the severity and frequency of wildfires by fueling drought and higher temperatures.
“Extreme heat and wildfires made worse by climate change, say scientists,” an Associated Press article proclaimed this week on NBC News.
“We now have very strong evidence that global warming has already put a thumb on the scales, upping the odds of extremes like severe heat and heavy rainfall,” Stanford University climate scientist Noah Diffenbaugh told the AP.
Yale Environment 360 declared in an Oct. 2 article, “Stark Evidence: A Warmer World Is Sparking More and Bigger Wildfires,” and concluded that “the fires being seen today ... are man-made, or at least man-worsened.”
This year’s U.S. wildfire season was forecast to be worse than average, and so far it has kept with predictions, with 98 wildfires blackening 4.6 million acres as of Monday, more than the 10-year average of 3.7 million acres, according to the National Interagency Fire Center.
California has been hit hardest, but firefighters made progress Monday. They lifted some evacuation orders on the Carr fire in Shasta County about 150 miles north of Sacramento, the deadliest and most destructive of the blazes, and reached 30 percent containment on the Ferguson fire near Yosemite National Park.
Six people have been killed so far in the California wildfires, including two firefighters, a great-grandmother and two of her great-grandchildren. About 410,000 acres have burned across the state amid unpredictable winds and high temperatures.
The death toll in Greece rose to 91 on Sunday as wildfires swept through seaside communities, at one point sending dozens of people out to sea to escape the flames engulfing the resort town of Mati, as shown on a dramatic video.
California Gov. Jerry Brown, a Democrat, cited global warming last week as a factor in his proposal to reduce the legal liability of Pacific Gas Electric Co., the utility company whose equipment was found to have sparked 15 of the state’s 2017 wildfires.
Mr. Brown and legislative leaders announced amended legislation July 2 to heighten California’s wildfire response, saying the effort “will help prepare the state to deal with the increasingly extreme weather and natural disasters caused by climate change.”
In a May report, “Indicators of Climate Change in California,” state Environmental Protection Agency Secretary Matthew Rodriguez said extreme weather events like wildfires are “not isolated incidents.”
“They are suggestive of the significant and increasingly discernible impacts of climate change in California,” Mr. Rodriguez said. “The most dramatic impacts include wildfires that are larger and more frequent, and the most severe drought since recordkeeping began.”
Others have argued that news coverage of fire disasters has contributed to the perception that wildfires driven by increased carbon dioxide levels in the atmosphere are raging out of control, despite evidence to the contrary.
″[M]any consider wildfire an accelerating problem, with widely held perceptions both in the media and scientific papers of increasing fire occurrence, severity and resulting losses,” said the Royal Society paper. “However, important exceptions aside, the quantitative evidence available does not support these perceived trends.”
In the Western United States, the study found that the limited data on fire severity “indicate little change overall, and also that area burned at high severity has overall declined compared to pre-European settlement.”
What’s responsible for the drop-off? The Science article pointed to an expansion of agriculture production in savannas and grasslands, resulting in a roughly 25 percent decrease in global burned area “despite the influence of climate.”
The discrepancy was not lost on climate skeptics such as Australia’s JoNova, who concluded Monday, “Global warming means a global fall in wildfires.”
Anthony Watts, who runs the Watts Up With That website, added: “Remember when we were told that wildfires would increase due to global warming? Never mind.”
University of Washington atmospheric sciences professor Clifford Mass said a host of factors may have contributed to this year’s California wildfires, including a modest temperature increase over the past several decades.
Add to that the drought, an increase of non-native invasive species, a huge influx of homeowners in fire-prone areas and aggressive fire suppression in the first half of the 20th century that left some forests overgrown and ripe for ignition.
“So there is a lot of talk of climate change ‘supercharging’ fires, but really no proof of it,” Mr. Mass said in an email. “And some fires are clearly NOT associated with climate change, like the wine country fires of last October.”
His conclusion? “I suspect climate change is a minor element in the CA wildfires, while fire suppression and human population growth into the wildlands are the dominant elements.”