Colorado and U.S. Forest Service firefighters are battling the state’s most destructive wildfires ever. Lightning and suspected arson ignited them four weeks ago, but scientists and federal officials say the table was set by a culprit that will probably contribute to bigger and more frequent wildfires for years to come: climate change.
In the past two years, record-breaking wildfires have burned in the West — New Mexico experienced its worst wildfire, Arizona suffered its largest burn and Texas last year fought the most fires in recorded history. From Mississippi to the Ohio Valley, temperatures are topping record highs and the land is thirsty.
“We’ve had record fires in 10 states in the last decade, most of them in the West,” said Agriculture Department Undersecretary Harris Sherman, who oversees the Forest Service. Over the past 10 years, the wildfire season that normally runs from June to September expanded to include May and October. Once, it was rare to see 5 million cumulative acres burn in a year, but some recent seasons have recorded twice that.
“The climate is changing, and these fires are a very strong indicator of that,” Sherman said.
A study published last month in Ecosphere, a peer-reviewed journal of the Ecological Society of America, projected that most of North America and much of Europe will witness a jump in the frequency of wildfires by the end of the century, mostly because of increasing temperatures.
“In the long run, we found what most fear: increasing fire activity across large parts of the planet,” said Max A. Moritz, a lead author of the study and fire specialist at the University of California Cooperative Extension.
Scientists say they do not have the data to link climate change to Colorado’s decreased snow and rain. But climate change has beenbeen linked to warmer temperatures that cause snow to melt earlier and rain to evaporate faster, parching the land, contributing to drought and drying out the vegetation that can fuel fires, said John Nielsen-Gammon, Texas’s state climatologist.
Under such conditions, snow and rain can fall at the same rate as before but the drier earth is slower to revive.
In Colorado’s warmer climate, a plague of pine beetles has thrived. Without extremely cold winters that reduce their numbers, the beetles breed twice per year instead of once. They nibble trees until they die, leaving millions of acres of potential firewood.
The High Park fire west of Fort Collins, where 33,000 residents were evacuated, is feeding on forest filled with trees eaten by beetles.
From March to May, most of Colorado had less than half the usual precipitation, and some areas had almost no rain or snow, said Nolan Doesken, director of the Colorado Climate Center at Colorado State University.