How climate change is affecting wildfire in the West
MISSOULA – It doesn't take a rocket scientist to figure out that we're in trouble in the climate, and forest fires are the most likely indicator.
A new study from the University of Montana shows just how bad forest fires in the West are getting. In a recent article for the journal Global Change Biology, University of Montana Associate Professor Philip Higuera tallies the statistics on the 2020 fire season, calling the numbers shocking, yet at the same time sadly predictable.
By the end of September, over 6.2 million acres had burned across the West, with more than half occurring in California – a full 3.7% of the state. In Oregon and Washington, nearly 1.9 million acres had burned, with more than half burned in just a few days.
More staggering are the human impacts: Millions of people who live the West have endured hazardous air, with estimates of thousands of smoke-related deaths, and over 10,000 structures have been damaged or destroyed and dozens of lives lost, said Higuera and article coauthor John Abatzoglou of the University of California, Merced.
The researchers describe how this widespread burning is directly associated with record-setting climate conditions across much of the West. The air was as starved of moisture as it’s ever been over the past 40 years in many regions, making vegetation extremely dry and flammable. This dry vegetation makes it easy for humans or lightning to ignite fires and for small fires to grow rapidly and evade fire suppression efforts. Unlike much of the rest of the West, Higuera said, Montana and the northern Rockies experienced below-average burning this summer, with temperatures and precipitation closer to normal.
Warmer, drier summers also help explain the dramatic increase in the area burned by wildfires over the past four decades. Through this lens, 2020 fits right in with other exceptional fires seasons of the 21st century.
“Human-caused climate change is a significant reason we are seeing more and more years with climate and fire seasons like 2020,” Higuera said “If this were just a lab experiment, the results would be elegant, but since this experiment includes our lives and livelihoods, it makes it appropriately shocking.”
The authors point out that fire is a natural and necessary component of many Western landscapes, but climate change and a number of other human factors are making this and other recent extraordinary fire seasons more destructive to human well-being.
“The alignment of ingredients for fire seasons like this past year are becoming more common as a result of climate change, management practices and human settlement,” Abatzoglou said. “We should expect, adapt and prepare for similar years moving forward.”
The authors hope the 2020 fire season serves as a catalyst for change – from individuals to federal policy – as have some of the most famous fire seasons of the past, like the great fires of 1910 that affected the Northern Rockies. The science and evidence highlighted in their editorial make it clear that addressing the challenges of living with wildfire necessarily includes addressing human-caused climate change.
The recent fire study from the University of Montana was published in the journal Global Change Biology on Oct. 13 and is available at https://onlinelibrary.wiley.com/doi/10.1111/gcb.15388.