STUDY: PEOPLE START 84% OF U.S. WILDFIRES
Climate change still a factor but humans lengthen fire season
The horrific wildfire that scorched Gatlinburg, Tenn., in November, killing 14 people, was human-caused — and that’s not unusual: Whether deliberate or accidental, a whopping 84% of all wildfires in the U.S. are started by people, says a new study.
The remaining 16% are started naturally, by lightning, according to the report, one of the most comprehensive to date.
The study also found that humans have added almost three months to the national fire season on average. “Thanks to people, the wildfire season is almost year-round,” said study lead author Jennifer Balch of the University of Colorado. Humans also account for nearly half the acreage burned each year.
Balch and her study co-authors looked at 1.5 million wildfires from 1992 to 2012 and found that the human-ignited fire season was three times longer than the lightning-ignited fire season and also added an average of 40,000 wildfires per year.
“Fires are burning earlier in the spring in the Southeast and later in the fall in the West,” Balch said. Fighting wildfires in the U.S. has exceeded $2 billion in recent years, the study said.
“Although considerable fire research in the United States has rightly focused on increased fire activity (larger fires and more area burned) because of climate change, we demonstrate that the expanded fire niche as a result of human-related ignitions is equally profound,” the study said.
Catastrophic fires have scorched the Western U.S. over the past decade. Several states, such as Washington and California, have seen some of their largest wildfires ever recorded.
“We have known for a long time that fires set by people are an extremely important factor in wildfire problems, but this study shows in detail how important people are in lengthening the fire season and contributing to increasing numbers of large wildfires,” said Thomas Swetnam of the University of Arizona, who was not involved in this research.
It’s not that people are becoming more careless or more arson is occurring, he said. He said lightning-caused fires are increasing in the West because of warming temperatures, earlier springs and droughts, which mean “that climate change is still a primary driver of the trends.”
The study appeared in the journal Proceedings of the National Academy of Sciences.
A building at the Westgate Smoky Mountain Resort goes up in flames during the spate of wildfires that hit Gatlinburg, Tenn.