Over the past 30 years wildfires have consistently become larger and more frequent in the Western U.S.—increasing by a rate of seven fires each year, a problem that shows no sign of stopping any time soon, according to research conducted by the University of Utah.
Using satellite images, the researchers found the total breadth of these fires has grown by a rate of nearly 90,000 acres per year—roughly equivalent to the size of Nevada.
This increasing problem is most likely tied to rising temperatures and extreme drought related to climate change, according to the report, which will be published in Geophysical Research Letters by the American Geophysical Union.
"These trends suggest that large-scale climate changes, rather than local factors, could be driving increases in fire activity," the scientists write. "The study stops short of linking the rise in number and size of fires directly to human-caused climate change. However, it says the observed changes in fire activity are in line with long-term, global fire patterns that climate models have projected will occur as temperatures increase and droughts become more severe in the coming decades due to global warming."
"Most of these trends show strong correlations with drought-related conditions which, to a large degree, agree with what we expect from climate change projections," said Max Moritz, a co-author of the study and a fire specialist at the University of California-Berkeley Cooperative Extension.
"But we are seeing a trend across the region. We are seeing it in deserts and grassland. The fact that we are seeing it in so many different ecosystems tells us something bigger is going on here," said the report's lead author Philip Dennison.
Earlier this week, as climate expert Jeff Masters notes, another group of Utah researchers detailed how this year's "remarkably extreme jet stream pattern" in North America, known as the "polar vortex," not only brought cold air to the Midwest and Eastern U.S., but also a "ridiculously resilient ridge" of high pressure over California, bringing the worst winter drought in record to California.
That same study found that this "vortex" was the most extreme on record, "and likely could not have grown so extreme without the influence of human-caused global warming," writes Masters.
"There is a traceable anthropogenic warming footprint in the enormous intensity of the anomalous ridge during winter 2013-14, the associated drought and its intensity," the study notes.
Looking ahead, the California Department of Forestry and Fire Protection said this week that California could have its most severe fire season of all time this year, issuing warnings to homeowners to prepare earlier than usual for the fire season.
“Over the next couple of months almost all of Northern California's gonna be at an above average potential for large and damaging wildfires," Cal Fire spokesman Daniel Berlant told the station. “These drought conditions that we're seeing are absolutely playing a huge factor in the size and the number of wildfires we're responding to.”