Fire ecologists with the U.S. Forest Service, University of California, Boise State University, and other academic institutions have made a surprisingly unintuitive discovery after analyzing 30 years of wildfire data, especially as the West grapples with profound drought and hotter weather.
The study, published last month in Environmental Research Letters, found that the American West is actually experiencing far fewer wildfires than in the past.
When comparing two separate 15-year chunks of data from 1992–2006 and 2007–2020, there were 31% fewer fires annually.
While the authors do not specifically outline why they chose these two timeframes, ecologists commonly view the mid-2000s as a climate change transition period, where hotter summers, longer droughts, and much drier air began to impact the environment.
But, with this finding came other statistics that are a little more obvious: when wildfires do spark, they are much more destructive than in the past – burning 40% more forested and unforested land overall.
By acreage, researchers found:
- Wildfires larger than 1,000 acres increased by 3%
- Wildfires larger than 25,000 acres increased by 63%
- Wildfires larger than 125,000 acres increased by 136%
The largest jump centered on lightning-caused wildfires, which researchers estimate are destroying 84% more land when compared to a time where climate change wasn’t as prolific as it is today – suggesting that forests are increasingly vulnerable during summer monsoon weather patterns.
The study attributes this “paradox,” of historically destructive, but fewer fires, to both human “influences” and the West’s uniquely warm and dry landscape.
Springtime, researchers point out, is seeing a large uptick in intentional – or unintentional – human-caused wildfires, effectively extending the front-end of the traditional fire season by 12 days.
Other seasons are experiencing alarmingly dramatic changes as well.
The fall, which has been historically characterized by cooler temperatures and fairly predictable precipitation in the West, has shifted to a nasty combination of warmer temperatures, late-year dryness, and strong downslope winds – resulting in megafires that are burning more than triple the amount of land.
The study highlighted the potential benefits of the findings, saying they can provide critical information for “operational decision support” and other decisions, such as targeted fire management and precious wildfire resource allocation.
