Wildfires Are 500% Larger Due to Climate Change
By edhat staff
A new study reports that California's wildfires have increased by 500% in annual burned areas. In the past ten years, California has seen half of the state’s 10 largest wildfires and seven of its 10 most destructive fires, including the Thomas Fire.
The 2017 Thomas Fire affected Ventura and Santa Barbara Counties and covered 281,893 acres making it the 2nd largest fire in California's history. The largest fire was July 2018's Mendocino Complex Fire at 459,123 acres while last year's Camp Fire in Butte County was the state’s deadliest wildfire ever killing 85 people.
The study was published last month in the journal Earth’s Future finding that California's fire outbreak is being driven by climate change. Since 1972, California experienced a fivefold increase in annual burned area, mainly due to more than an eightfold increase in summertime forest‐fire and was very likely driven by drying of fuels promoted by human‐induced warming, according to the paper.
"Warming effects were also apparent in the fall by enhancing the odds that fuels are dry when strong fall wind events occur. The ability of dry fuels to promote large fires is nonlinear, which has allowed warming to become increasingly impactful. Human‐caused warming has already significantly enhanced wildfire activity in California, particularly in the forests of the Sierra Nevada and North Coast, and will likely continue to do so in the coming decades," according to the paper.
Northern California summers have warmed by about 2.5 degrees Fahrenheit (1.8 degrees Celsius) on average since 1970. Increased heat dries out soil and trees turning land into fire fuel that can be easily sparked. Authors of the paper state even if there's a wet winter, a summer heatwave can dry out the area making it susceptible to wildfire.
The authors state increased heat is the clearest result of human-caused climate change, according to The Atlantic.
The paper also states their findings are limited to summertime fires in forests, such as the Whittier Fire which sparked July 2017 in the Los Padres National Forest burning 18,430 acres. However, they also found the amount of burned non-forest area, including many of Southern California’s shrub and grassland fires, has not significantly increased.
Autumn wildfires, such as the Camp Fire, will get more common as climate change continues, the paper suggests.
When posed with climate change not being the only factor of increased fire in California, the authors state the fundamental relationship between excess heat and additional fire never changes in the study’s data, suggesting that across five decades, the forests have remained the same and only the air temperature has changed, reports The Atlantic.
Looking forward, a worst-case scenario predicts the majority of California forests have all burned to leave a landscape of grassland and desert if nothing is done to reduce carbon pollution.