Shawn Vestal: Warming climate driving wildfires higher into the mountains – The Spokesman-Review
We know that forest fires have been burning bigger and hotter, summer after summer.
Now research shows they’re also burning higher – destroying forests in the upper elevations of the Mountain West that used to stay too cool and wet to burn, even at summer’s peak. Not only has this expanded the amount of land at risk of wildfire, but it has fed a vicious cycle that deepens the drought crisis, by reducing the forest structures that typically hold onto snowpack deep into the year and fostering warmer streams at higher elevations.
This unseasonably sweltering week was the perfect time to consider what’s coming in the next couple of months. Weather isn’t climate, of course – just as the continued existence of snow does not disprove global warming, neither do a few unseasonably hot days alone prove it.
And yet the record heat, along with widespread drought conditions, offered a nice, sweaty opportunity to revisit the state of the climate crisis and to remember what’s probably on the horizon: another destructive wildfire season.
For more than a decade, the trend has been stark: more acres burned, more homes destroyed, more horrible air quality days every summer. Recent research indicates only more of the same on the horizon.
A new global analysis by the World Meteorological Association, released in April, shows 2020 was one of the three hottest years on record, even though there was a “cooling La Niña event.” That year also concluded the warmest decade yet recorded.
Regional research bears out this trend. New calculations by the National Oceanic and Atmospheric Administration show that Spokane’s 30-year average temperature increased 0.4 degrees since the last analysis a decade ago. The increases were sharpest in the summer months, where average temperatures increased by around 1 degree, depending on the month.
It’s new information, but it’s also very familiar. We’ve seen this happening for a long time now.
Meanwhile, anyone who treated the pandemic with sanity and seriousness has to be even more concerned about our ability to respond to this crisis – or any crisis that requires a collective response to a collective problem, so long as a politicized minority remains at war with factual knowledge.
The new research about fires burning higher in the mountains contains a rebuttal to denial arguments, and especially to the idea that these smoky, destructive summers are chiefly the result of not enough logging.
Because the latest data focuses on the upper reaches of mountain ranges that are not affected by logging or the lack of it, the findings are even more directly tied to warming.
“While some people focus on historical fire suppression and other forest management practices as reasons for the West’s worsening fire problem, these high-elevation forests have had little human intervention,” according to a news release by the authors announcing the research. “The results provide a clear indication that climate change is enabling these normally wet forests to burn.”
A team of climate scientists and engineers published the study in late May in the Proceedings of the National Academy of Sciences, demonstrating that forest fires have been climbing upward at unprecedented rates.
Researchers analyzed all fires larger than 1,000 acres in the West between 1984 and 2017. They found that, while the amount of land burned in these fires grew at every elevation level, the starkest change was above 8,200 feet. (For perspective, Mount Spokane’s elevation is 5,887 feet).
The acreage burned above 8,200 feet more than tripled between the early years of that survey (1984-2000) and the later ones (2001-17). Most of these areas are remote mountains and forests, with some small towns and ski areas.
“Our results show that climate warming has diminished the high-elevation flammability barrier – the point where forests historically were too wet to burn regularly because the snow normally lingered well into summer and started falling again early in the fall,” the authors said. “Fires advanced about 826 feet uphill in the Western mountains over those three decades.”
That has resulted in an expansion of more than 31,000 square miles of “fire territory in the West,” the researchers said.
“That means a staggering 11% of all Western U.S. forests – an area similar in size to South Carolina – are susceptible to fire now that weren’t three decades ago.”
Fires at high elevations damage the ability of mountains to operate as the region’s “water towers” – holding snowpack and providing a sustained source of water through the summer. Burn scars reduce the amount of snow that accumulates, and the loss of trees eliminates the foliage that anchors and stabilizes snowpack. The loss of tree canopy exposes mountain streams to the sun, warming up headwater streams.
It’s just one more piece of a very large body of evidence telling us what’s happening with these massive wildfires.
The only real question is whether we pay attention.