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What Tucker Carlson gets wrong about causes of wildfires in U.S. West

Posted on 6 October 2020 by greenman3610

This is a re-post from Yale Climate Connections

Western wildfires – their principal causes and not just their impacts – have gotten some prime time media attention in recent weeks, including even in the final segment of the September 29 first presidential “debate” between the two major party candidates.

Is it forest management or land management generally that’s the principal cause for sparking the fires that have crumbled hundreds of thousands of western acres into ashes? Or is it climate change? Or is it both?

That’s the focus of independent videographer Peter Sinclair’s new video for Yale Climate Connections. He sets the table using a CBS clip capturing the historical scope of the current fire season’s blazes. And then cuts to Fox News commentator Tucker Carlson telling his vast audience that “all we have is conjecture from a handful of scientists and many politicians” pointing the finger primarily at climate change. “None of whom has reached a definitive conclusion,” he says of those holding that view.

After National Center for Atmospheric Research distinguished scholar Kevin Trenberth and Harvard professor Loretta Mickley pour water on those embers of misinformation, the video shows Carlson quoting words he attributes to UCLA climate scientist Daniel Swain appearing to support Carlson’s take on things.

But Swain comes in to say he’s never spoken to Carlson, his staff, or others at Fox on the issue. He thinks that he’s been misrepresented through a cherry-picked paraphrase of his actual position. He points to an article in MIT Technology Review as the likely source for Carlson’s flawed conclusion.

At that point, the headline of the article in question is shown: “Yes, climate change is almost certainly fueling California’s massive fires.” In that article, Swain is reported as saying extreme summer lightening events in coastal parts of Northern California are so infrequent that “it’s hard to assess whether climate change played a role in sparking the fires.”

Important question: What happens after the initial spark?

Swain, in the new video, says, “The reality is that there’s always going to be sparks that can start a fire. The real question is what happens given that spark? All of the evidence points in the direction of strongly suggesting that those fires are becoming larger, more intense, and behaving more extremely because of climate change.”

The Sinclair video reports also that the Fox piece by Carlson omitted “the very next paragraph” from the MIT Technology Review source report: “But so called extreme weather attribution studies have clearly and repeatedly found that climate change exacerbates heat waves, which help create the conditions for wildfires to burn intensely and spread rapidly.”

Jonathan Overpeck, Ph.D., of the University of Michigan, says the current prolonged western U.S. drought is “not a drought of yore.” Instead, it’s an example of an aridification – the result of Earth’s warming temperatures and the further drying out of already dry regions.

Mickley, of Harvard, points not so much to the specific spark that might lead to a wildfire as to “the extent of the fires, how big the fires grow really depends on the weather.”

Back to Swain. He points to the once-famous “Smokey the Bear” forestry fire public service campaigns well-known to many Americans over a certain age: “Only YOU can prevent forest fires.” He says the century-long drive to stomp out virtually every fire, regardless of risk posed, led to a “deficit of ‘good fire,'” the kind of planned burns and other controlled fires that helped consume excessive underbrush.

That well intentioned, but perhaps overly zealous, campaign resulted in a “buildup of unusually dense vegetation, which unfortunately has become a buildup of unusually dense fuel for wildfires over the past few decades.” Overpeck agrees, saying forested areas could benefit from more controlled fires, but “the job is gigantic” and resources to do it inadequate.

“Just about all the fire scientists I talk to agree that climate change is making” the wildfire challenge “worse than it would be otherwise,” Swain says in the video.

To Mickley, the situation appears bound to only get worse in coming years. “Not just one, but all the climate models predict uniformly higher temperatures and drought in the western U.S. by 2050, and certainly by 2100. The outcome will be “really large increases in the area burned,” she says, with some areas seeing 25% more acres burned and others seeing a four-fold, or 400%, increase in acreage burned in wildfires.

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Comments 1 to 8:

  1. "Overpeck agrees, saying forested areas could benefit from more controlled fires, but “the job is gigantic” and resources to do it inadequate."

    It takes a lot of resources to fight the fires too. A thriving forestry industry in CA would be profitable. Some of those profits would go to controlled burns. We don't hear of huge wild fires in the American southeast, where forestry is a huge industry and controlled burns are routine.

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  2. JoeZ, increased forest fire activity across the western U.S. in recent decades is due to a number of factors, including a history of fire suppression and human encroachment in forest regions, natural climate variability, and human-caused climate change. Forest management would help in some areas, however the wildfire numbers and burned area are also increasing in non-forest vegetation types. Wildfire activity appears strongly associated with warming temperatures (California spring/summer temperatures have increased by more than 5 degrees Fahrenheit since 1970) and earlier spring snowmelt.

    Source: NASA

    "For all ecoregions combined, the number of large fires increased at a rate of seven fires per year, while total fire area increased at a rate of 355 km2 per year. Continuing changes in climate, invasive species, and consequences of past fire management, added to the impacts of larger, more frequent fires, will drive further disruptions to fire regimes of the western U.S. and other fire-prone regions of the world."

    Since the 1980s, the wildfire season has lengthened across a quarter of the world's vegetated surface.

    "We show that fire weather seasons have lengthened across 29.6 million km2 (25.3%) of the Earth’s vegetated surface, resulting in an 18.7% increase in global mean fire weather season length. We also show a doubling (108.1% increase) of global burnable area affected by long fire weather seasons (>1.0 σ above the historical mean) and an increased global frequency of long fire weather seasons across 62.4 million km2 (53.4%) during the second half of the study period."

    "The start of the Southwestern fire season—as indicated by the date of first large-fire discovery—has shifted more than 50 days earlier since the 1970s, accounting for about one-third of the increase in the length of the fire season. The substantially earlier SW fire season start is consistent with warmer temperatures and earlier spring seasons leading to earlier flammability of fuels in SW forests."

    "Anthropogenic increases in temperature and vapor pressure deficit significantly enhanced fuel aridity across western US forests over the past several decades and, during 2000–2015, contributed to 75% more forested area experiencing high (>1 σ) fire-season fuel aridity and an average of nine additional days per year of high fire potential.

    Anthropogenic climate change accounted for ∼55% of observed increases in fuel aridity from 1979 to 2015 across western US forests, highlighting both anthropogenic climate change and natural climate variability as important contributors to increased wildfire potential in recent decades.

    We estimate that human-caused climate change contributed to an additional 4.2 million ha of forest fire area during 1984–2015, nearly doubling the forest fire area expected in its absence.

    Natural climate variability will continue to alternate between modulating and compounding anthropogenic increases in fuel aridity, but anthropogenic climate change has emerged as a driver of increased forest fire activity and should continue to do so while fuels are not limiting."

    "By 2100, if greenhouse gas emissions continue to rise, one study found that the frequency of extreme wildfires would increase, and the average area burned statewide would increase by 77 percent. In the areas that have the highest fire risk, wildfire insurance is estimated to see costs rise by 18 percent by 2055. "

    "The clearest link between California wildfire and anthropogenic climate change thus far has been via warming-driven increases in atmospheric aridity, which works to dry fuels and promote summer forest fire, particularly in the North Coast and Sierra Nevada regions.

    Importantly, the effects of anthropogenic warming on California wildfire thus far have arisen from what may someday be viewed as a relatively small amount of warming. According to climate models, anthropogenic warming since the late 1800s has increased the atmospheric vapor-pressure deficit by approximately 10% and this increase is projected to double by the 2060s. Given the exponential response of California burned area to aridity, the influence of anthropogenic warming on wildfire activity over the next few decades will likely be larger than the observed influence thus far where fuel abundance is not limiting.

    Since the early 1970s, California's annual wildfire extent increased fivefold, punctuated by extremely large and destructive wildfires in 2017 and 2018. This trend was mainly due to an eightfold increase in summertime forest‐fire area and was very likely driven by drying of fuels promoted by human‐induced warming. Warming effects were also apparent in the fall by enhancing the odds that fuels are dry when strong fall wind events occur.

    The large increase in California’s annual forest-fire area over the past several decades is very likely linked to anthropogenic warming.

    Human‐caused warming has already significantly enhanced wildfire activity in California, particularly in the forests of the Sierra Nevada and North Coast, and will likely continue to do so in the coming decades."

    Wildfire mitigation efforts can reduce wildfire intensity and severity while improving forest resilience to fire, insects and drought. The total area burned by wildfires is a trend driven by the warming climate (which is warming because of human activities), so mitigation efforts will not likely be able to affect the total area burned trend.

    Droughts in the Southwestern US have been made nearly half-again worse by human activities and are projected to worsen yet.

    These droughts couple with rising temperatures, reduced soil moisture and lower humidity to kill vast amounts of trees, providing an ever-increasing amount of fuel loads for wildfires.

    California’s frequency of fall days with extreme fire-weather conditions has more than doubled since the 1980s. Continued climate change will further amplify the number of days with extreme fire weather by the end of this century.

    California Fires

    There is strengthened evidence that climate change increases the frequency and/or severity of fire weather around the world. Land management alone cannot explain recent increases in wildfires.

    Analysis shows that:

    • Well over 100 studies published since 2013 show strong consensus that climate change promotes the weather conditions on which wildfires depend, enhancing their likelihood.

    • Natural variability is superimposed on the increasingly warm and dry background conditions resulting from climate change, leading to more extreme fires and more extreme fire seasons.

    • Land management can enhance or compound climate-driven changes in wildfire risk, either through fuel reductions or fuel accumulation as unintended by-product of fire suppression. Fire suppression efforts are made more difficult by climate change.

    • There is an unequivocal and pervasive role of climate change in increasing the intensity and length in which fire weather occurs; land management is likely to have contributed too, but does not alone account for recent increases in wildfire extent and severity in the western US and in southeast Australia.

    Human-induced climate change promotes the conditions on which wildfires depend, enhancing their likelihood and challenging suppression efforts. Although the global area burned by fires each year is declining, the majority of this trend is explained by conversion of natural savannahs and grasslands to agriculture in Africa (Andela et al. 2017). In contrast, the area burned by forest wildfires is increasing in many regions, including in the western US and southeast Australia.

    • “Fire weather” refers to periods with a high likelihood of fire due to a combination of high temperatures, low humidity, low rainfall and often high winds.

    • Human-induced warming has already led to a global increase in the frequency and severity of fire weather, increasing the risks of wildfire.

    • Land management can ameliorate or compound climate-driven changes in wildfire risk.

    • Wildfires can have broad impacts for human health and wellbeing and for the natural environment.

    US fires:

    • Fire weather has become more frequent and intense in western US forests.

    • Fire weather is driving more wildfire activity in western US forests.

    • Demographic factors alone cannot account for the magnitude of the observed increase in wildfires in the western US, but increased population leads to greater impacts.

    Land management practices are contributing factors, but cannot alone explain the magnitude of the observed increase in wildfires extent in the western US forests in recent decades.

    Australia fires:

    • The scale of the 2019–2020 bushfires was unprecedented.

    • Fuel management through prescribed burns and improved logging practice cannot fully mitigate increased wildfire risk due to climate change.

    • Extreme weather and Pyroconvection are projected to increase wildfire risk under future climate change in southeastern Australia.

    Scientific evidence that climate change is causing an increase in the frequency and extent of fire weather, contributing to extreme wildfires around the world, continues to mount.

    The severe droughts in the USA and Australia are signs that the tropics, and their warm temperatures, are expanding in the wake of climate change, due to the warming of the subtropical ocean.
    PDF here

    Climate change will continue to drive temperature rise and more unpredictable rainfall in many parts of the world, meaning that the number of days with “fire weather” – conditions in which fires are likely to burn – is expected to increase in coming decades.

    Carbon Brief Wildfire explainer

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  3. Daniel B,

    What your very impressive statistics points out is that the window for safe controlled burns has shrunk and in some years has disappeared altogether. This has occurred in other parts of the country as well. But that doesn't mean that safe controlled burns should be abandoned as a management tool since fire is a central component of most terrestrial ecosystems. In fact, it makes the increased risk of catastrophic scale fires due to aridification makes controlled burns even more important than ever because of the alternatives.  A wildfire season in Kansas in 2016 burned over 400,000 acres of mostly grassland that was being invaded by woody species such as highly flammable eastern red cedar, Juniperus virginiana. Had controlled burns been used in those areas during wetter years to control the fuel supply, the damage would have been far less, and as folks found out in following years, the pastures were greatly improved by the removable of the woody invasives. So the trick is to adapt the controlled burn regimen to actively seek out the shrinking windows of opportunity that climate change has created.

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  4. Daniel,

    While wildouglscountry argument is not without merit, reducing you post to the descriptive of "impressive statistics" seems a rather underhanded way to belittle what is one of the most comprehensive examination of the problem I have seen. Would you agree for others to repost, copy/paste with proper attribution?

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  5. Philippe, repost away! 

    What's important is the public understanding of the science and that comes best with widespread dissemination.

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  6. JoeZ@1 said: "We don't hear of huge wild fires in the American southeast, where forestry is a huge industry..."  Is the Southeast drying up?  If not, then there's the likely cause of the huge wild fires you didn't hear.

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  7. Daniel Bailey, I've actually reposted your comment over at Realclimate, because it backs up some points I have just made, and it might be of general interest. So many thanks.

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  8. JoeZ:" It takes a lot of resources to fight the fires too"

    True, and these resources come from the same pool as those for management and prevention. So, repeated catastrophic seasons deplete the resources for prevention.

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