As wildfires blaze throughout the American West, climate change skeptics are downplaying both their devastating impact on forests and the role of rising global temperatures in sparking infernos.
This point of view was expressed in a piece published this week by Michael Shellenberger, an environmental activist and writer whose new publications seek to minimize the threat of climate change as “environmental alarmism.” Forests regularly burn, Shellenberger writes, and “old-growth redwood forests need fire to survive and thrive.”
In making his claim, Shellenberger focuses narrowly on redwoods, which comprise only a small portion of Western forests and even less of what is burning. While it’s true that fire has always been an important part of the life cycle for Western forests, and redwoods may be especially resilient because they grow in damp coastal areas, other key tree species in drier forests aren’t faring so well.
A new study led by the University of Colorado-Boulder suggests that forests in the Southern Rockies are increasingly unlikely to recover from wildfires. Instead, they’ll convert to grasslands and shrublands.
“The big takeaway here is that we can expect to have an increase in fire continue for the foreseeable future, and, at the same time, we are going to see much of our land convert from forest to non-forest,” said study co-author Tom Veblen, professor of geography at CU Boulder, in a press release.
The culprit? The study — titled “A changing climate is snuffing out post‐fire recovery in montane forests” — points to climate change.
“Climate warming is increasing fire activity in many of Earth’s forested ecosystems,” the study states. “Our findings suggest that future increases in climatic water deficit (CWD) and an increased frequency of extreme drought years will substantially reduce post‐fire seedling densities.”
Adds Veblen: “This study and others clearly show that the resilience of our forests to fire has declined significantly under warmer, drier conditions.”
Research conducted by Steve Sillett at Humboldt State University suggests a similar scenario for redwoods growing on the southern and eastern edges of their range, where they’ve been stressed by drought.
And as fire ecologist Kristen Shive, who conducts research for the Save the Redwoods League, observed in an interview with Scientific American: “As we get more hotter and drier days, climate change will influence wildfire. But what I think is of concern is that we do know fire seasons are getting longer and that we’re having more heat waves. If we keep having more of those, we’re going to be more fire-prone in these [coastal] areas.”
Shellenberger insists otherwise, writing: “California’s fires should indeed serve as a warning to the public, but not that climate change is causing the apocalypse. Rather, it should serve as a warning that mainstream news reporters and California’s politicians cannot be trusted to tell the truth about climate change and fires.”
A new report by the Congressional Research offers its own sober assessment: “Every year since 2000, an average of 71,300 wildfires burned an average of 6.9 million acres. This figure is more than double the average annual acreage burned in the 1990s (3.3 million acres), although a greater number of fires occurred annually in the 1990s (78,600 on average). As of August 3, 2020, over 32,000 wildfires have burned nearly 2.2 million acres this year.”
California accounts for some 1.3 million acres of that total. But Shellenberger asserts that the Golden State’s 2020 fires are nothing unusual. Instead, he writes, they’ve been over-hyped by “activist journalists and politicians [determined] to blame climate change for everything.”
However, the study published in the journal Global Ecology and Biogeography looks specifically at the role of climate change, using statistical modeling to project what might happen to Western forests over the next 80 years under two scenarios: no attempt to reduce greenhouse gas emissions and climate change escalates unchecked, and moderate attempts that result in emissions beginning to decline after 2040.
“We project that post-fire recovery will be less likely in the future, with large percentages of the Southern Rocky Mountains becoming unsuitable for two important tree species—ponderosa pine and Douglas fir,” said lead author Kyle Rodman, who is now a postdoctoral research associate at the University of Wisconsin-Madison, in a press release.
While the study looks specifically at the Front Range, which extends from southern Wyoming through central and western Colorado to northern New Mexico, ponderosa pine and Douglas fir also dominate forests in California, Oregon and eastern Washington state. In addition to supporting wildlife habitat, logging and recreational uses, forest watersheds are an important source of drinking water for Western residents.
The study analyzed 22 areas, encompassing 710 square miles, that had burned as early as 1988 and as recently as 2002. Some 80 percent of the plots surveyed had no new trees even 15 years after the fire. Forests at higher elevations, where temperatures are cooler and rainfall more abundant, were more resilient. The study also found that more recent burn areas were less likely to recover than forests that burned a century or more ago.
Statistical modeling projected that by 2051, less than 18 percent of Douglas fir and ponderosa pine forests will likely recover, even if humans attempt to control climate change by reducing greenhouse gas emissions. But if no effort is made, that number drops to just 6.3 percent for Douglas fir and 3.5 percent for pine.
The study’s authors think their research will help land managers make better decisions on where to invest reforestation efforts. Rodman, who led the research while a PhD student at CU-Boulder, also hopes it will motivate actions to reverse climate change.
“This was a hard study to write and can be a bit depressing to read, but there are some positive takeaways,” Rodman said in a press release. “If we can get a handle on some of these trends and reduce our greenhouse gas emissions, the outcomes may not look so dire. The future is not written in stone.”