Wildfires have been getting bigger and burning more ground in recent decades. But paradoxically, recent data shows fewer fires are being started.
“The most striking finding in our study was that the total number of wildfires has actually gone down, but the amount of land that’s burning … has gone up,” said Amirhossein Montazeri, a PhD student at Boise State University and lead author of a recent article published by the journal Environmental Research Letters.
Specifically, the researchers looked at more than 750,000 wildfires in the West between 1992 and 2020. In the second half of that period, the number of reported wildfires were down by 31%, but acreage burned was up 40%.
Montazeri explained this seeming paradox in two ways: humans account for the majority of wildfire starts, and those fell substantially between the two periods – some 33% – suggesting awareness and prevention campaigns may be working. But at the same time, climate change has led to warmer and drier conditions, which promote rapid fire growth.
The number of large and very large fires, those bigger than 25,000 and 125,000 acres, grew by 63% and 136% respectively over the study period. The number of smaller fires declined, with those under 10 acres falling by 33%.
Another recent paper reported on by the Mountain West News Bureau found that, in addition to growing in size, wildfires are burning more intensely – a trend also driven by human-caused climate change.
Additionally, Montazeri and his team found there are weather and fuel moisture thresholds beyond which fires start and grow quickly. That information, Montazeri argued, could help land managers decide when it’s safe to set prescribed fires and let fires burn – or when aggressive suppression may be in order.
This story was produced by the Mountain West News Bureau, a collaboration between Boise State Public Radio, Wyoming Public Media, Nevada Public Radio, KUNR in Nevada, KUNC in Northern Colorado, KANW in New Mexico, Colorado Public Radio and KJZZ in Arizona as well as NPR, with support from affiliate newsrooms across the region. Funding for the Mountain West News Bureau is provided in part by the Corporation for Public Broadcasting and Eric and Wendy Schmidt.
