How Bad Science & Horrific Journalism Misrepresent Wildfires and Climate

How Bad Science & Horrific Journalism Misrepresent Wildfires and Climate 

As one wildfire expert wrote, “Predicting future fire regimes is not rocket science; it is far more complicated than that.” But regardless of accuracy, most people are attracted to very simple narratives such as: more CO₂ causes global warming causes more fires. Accordingly in the summer of 2019, CNN trumpeted the headline California wildfires burn 500% more land because of climate change. They claimed, “the cause of the increase is simple. Hotter temperatures cause drier land, which causes a parched atmosphere.” CNN based their claims on a scientific paper by lead authors Park Williams and John Abatzoglou titled Observed Impacts of Anthropogenic Climate Change on Wildfire in California. The authors are very knowledgeable but appear to have hitched their fame and fortune to pushing a very simple claim that climate change drives bigger wildfires. As will be seen, their advocacy appears to have caused them to stray from objective scientific analyses. 

If Williams and Abatzoglou were not so focused on forcing a global warming connection, they would have at least raised the question, ‘why did much bigger fires happen during cooler decades?’ The 1825 New Brunswick fire burned 3,000,000 acres. In Idaho and Montana the Great Fire of 1910 burnt another 3,000,000 acres. In 1871, the Great Michigan Fire burned 2,500,000 acres. Those fires were not only 6 times larger than California’s biggest fire, they occurred in moister regions, regions that don’t experience California’s Mediterranean climate with its guaranteed months of drought each and every summer. If those huge devastating fires occurred in much cooler times, what are the other driving factors of big wildfires? 

Bad analyses cause bad remedies, and here is why Williams and Abatzoglou’s last paper exemplifies a bad scientific analysis. Analyzing changes in California’s burned areas from 1972 to 2018 they claimed, “The clearest link between California wildfires 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.” But natural cycles of low rainfall due to La Niñas also cause dry fuels. The increase in burned area is also attributed to increases in human ignitions such as faulty electrical grids, to increased surface fuels from years of fire suppression, and to changes in vegetation that increased the abundance of easily ignited fine fuels like annual grasses. Furthermore, temperatures in some local regions experiencing the biggest fires have not been warming over the past 50 years (See temperature graphs in this essay’s last segment. Data from Western Regional Climate Center). All those factors promote rapid wildfire spread and greater burned areas. Although good science demands separating those contributing factors before analyzing a possible correlation between temperature and area burned, Williams and Abatzoglou oddly did not do so! That’s bad science. 

Although Williams and Abatzoglou did acknowledge that other factors modulate the effects of warming on burned areas they admitted their statistical correlations did not “control” for those effects. To “control” for all those contributing factors, they could have easily subtracted estimates of burned areas associated with those factors. For example, a 2018 research paper estimates, “Since the year 2000 there’ve been a half-million acres burned due to powerline-ignited fires, which is five times more than we saw in the previous 20 years.”  Did Williams and Abatzoglou not do the needed subtractions of other well-established factors because it would weaken their global warming correlation?

Similarly, CNN journalists were content to simply blame climate change. However, in light of the increasing devastation caused by powerline-ignited fires, good investigative journalists should have asked the former California Governor Jerry Brown if he now regrets having vetoed the bipartisan bill crafted to secure the power grid; an action that could have saved so many lives and property. Instead CNN simply promoted Brown’s persistent climate fearmongering quoting, “This is only a taste of the horror and terror that will occur in decades.”

Ignoring the complex effects of human ignitions, CNN also parroted claims that global warming is causing fire season to last all year. But as seen in the graph below from a 2017 wildfire study, the United States’ natural fire season is due to lightning and only dominates during the months of July and August, when California’s high wind events are low. In contrast it is human ignitions that extend fire season, dramatically increasing ignitions throughout the winter months when fuel moisture is higher, and into seasons when cooling desert air generates strong episodes of Santa Ana and Diablo winds. Those high winds cause fires to spread rapidly, burning 2-3 times more area than fires ignited during low winds, and California’s most destructive fires recently occurred during those high wind events. However, like other researchers, Williams and Abatzoglou reported no trend in those destructive California winds. Furthermore, climate models suggest a warming climate should cause weaker winds. So, without a change in California’s windy conditions, high winds can’t be blamed, directly, for the increased burned areas. However, because more human-caused ignitions occur during the winter, it increases the probability that more fires will be amplified by those strong winter winds. As US Geological Survey’s wildfire expert states, “Some will argue that it’s climate change but there is no evidence that it is. It’s the fact that somebody ignites a fire during an extreme [wind] event.”

Human Ignitions Extend Wild Fire Season  from Balch 2017

The timing of human ignitions is but one driver of more and bigger fires. Increased surface fuels are another huge factor. It is well known that past fire suppression has allowed surface fuels to accumulate in forests, leading to bigger and more devastating fires. But the changes in surface fuels are more complex. Some scientists point out that certain logging practices spread “invasive grasses called cheat grass, for example, and other ones that form this really thick mat across the area after logging and that grass just spreads flames very rapidly and fires burn very intensely through that.” California’s Democrat congressman Ro Khanna has been arguing that the U.S. Forest Service policy to clear cut after a wildfire is making California’s forest fires spread faster and burn hotter by increasing the forest floor’s flammable debris. Khanna says, “Because we don’t have the right science, it is costing us lives, and that is the urgency of getting this right.” 

Controlling the spread of cheat grass is urgently needed. Grasses are “fine fuels” that ignite most easily. The 2018 Carr Fire was California’s 7^th largest fire and threatened the town of Redding, California. It started when a towed trailer blew a tire causing its wheel rim to scrape the asphalt creating a spark which ignited roadside grasses. Those grasses carried the fire into the shrublands and forests. Grasses are classified as 1-hour fine fuels, meaning they become highly flammable in just one hour of warm dry conditions. Climate change is totally irrelevant. It does not matter if it was wet and cool, or hot and dry during previous days, weeks or years. Just one hour of warm dry fire weather sets the stage for an explosive grass fire that then gets carried into the forests. Fire weather happens every year, and partially explains why fires could burn 3,000,000 acres in the cool 1800s.

It was not human ignition but lightning that caused the 2012 Rush Fire. It was California’s 4^th largest fire burning 272,000acres of sagebrush habitat, which then continued to burn additional area in Nevada. Historically, because surface fuels are scarce, hot dry sagebrush habitat rarely burned (once every 60-100 years). But invasions of non-native cheat grass have now provided ample fuel to turn small lighting fires into huge conflagrations. Eleven of the USA’s 50 biggest fires in last 20 years are in the Great Basin, where invasive cheatgrass is spreading. Nevada’s largest fire was the 2018 Martin Fire. Rapidly spreading through the cheat grass, it burned 439,000 acres. Cheat grass fires are a great concern for biologists trying to protect the threatened Sage Grouse as cheat grass-dominated sagebrush habitat now burns every 3-5 years. Habitat with high cheat grass abundance are “twice as likely to burn as those with low abundance, and four times more likely to burn multiple times between 2000-2015.”

When experts estimate impending fire danger, they determine how fast a fire will spread. The Spread Component considers the effects of wind and slope and daily changes in the moisture content of the surface fuels. Large dead trees may become flammable after 1000 hours of warm dry conditions, but still thick fuels only ignite if fast burning surface fuels supply enough heat. Thus, the Spread Component only considers smaller-diameter fuels like grasses that can dry out in an hour, as well as twigs and small branches that dry out within 10 to 100 hours. Central and Southern California are dominated by shrubby habitat with small diameter fuels that allow fire to spread rapidly. The December 2017 Thomas Fire was California’s 2nd largest fire. Its human ignition coincided with a Santa Ana wind event resulting in the burning of 282,000 acres in southern California. 

Counter-intuitively Williams and Abatzoglou found the correlation between burned area in the hotter and drier climate of California’s Central and South Coast to be “relatively weak”. Accordingly, they reported “Annual burned area did not change significantly in Central and South Coast.” That insignificant climate effect over half of California escaped the notice of journalists who only cherry-picked the researcher’s more alarming climate narratives. Most interesting, Williams and Abatzoglou suggested the lack of a climate-change correlation with California’s Central and South Coast burned areas was because fires there were “strongly manipulated by humans via ignitions, suppression, and land cover change.” 

Lightning is rare along California’s Central and South Coast, so nearly 100% of those fires are ignited by humans. As California’s population doubled since the 1970s, adding 20 million people, the probability of more human-started fires has increased. Unlike forested areas where fire suppression builds up deadly surfaced fuels, California’s Central and South Coast need to suppress fires. Due to more frequent fires caused by humans, shrublands are converting to grasslands.  The increased fine fuels of the grasslands more readily ignite and spread fire.  Furthermore, California’s natural climate undergoes wet years due to El Nino followed by dry La Nina years. Wet years make fine fuels more abundant. Thus fire suppression is needed to prevent more frequent fires caused by the conversion of shrublands to grasslands.

In contrast to the insignificant changes in burned areas in California’s southern half, Williams and Abatzoglou reported burned areas in the Sierra Nevada and the North Coast increased by more than 600%, which they attributed to human-caused climate change. They reported, “During 1896–2018, March–October Tmax [maximum temperature] averaged across the four California study regions increased by 1.81 °C, with a corresponding increase in VPD [ Vapor Pressure Deficit - a measure of atmospheric dryness] of 1.59 hPa (+13%)…The observed trends in Tmax and VPD are consistent with trends simulated by climate models as part of the CMIP5 experiments, supporting the interpretation that observed increases in California warm‐season temperature and VPD have been largely or entirely driven by anthropogenic forcing.”

But how can only half of California’s fires be due to global warming and the other half not? All of California is “strongly manipulated by humans via ignitions, suppression, and land cover change”?  Were Williams and Abatzoglou straying from objective science? 

Part of the problem is their ill-advised use of a maximum temperature averaged for all California. Several studies have reported that maximum temperatures in the northern half of California have not exceeded the high temperatures of the 1930s. Because the early 20^th century temperatures were deemed natural, unless recent temperatures exceed the natural 1930s, then human-caused warming is unlikely. Curiouser and curiouser, southern California has experienced temperatures that exceeded the 1930s. Yet there Williams and Abatzoglou did not find a significant effect from climate change. 

Regardless Williams and Abatzoglou claimed “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.”  Yet summer maximum temperatures, averaged from March through October, located in the vicinity of California’s big fires do not indicate global warming. For example, the August 2013 Rim Fire centered around Yosemite National Park, was California’s 5^th largest fire and 2^nd largest in northern California, burning 257,000 acres. It was started by a hunter’s illegal campfire that he let get away. Unfortunately, there is no cure for stupid. Nonetheless, Yosemite’s maximum temperatures were warmer in the early 1900s.  However, an in depth study of the Rim Fire found a strong correlation with the amount of shrubland interspersed with the trees.

Trend in Yosemite NP maximum summer temperatures

The November 2018 Camp Fire was California’s deadliest fire destroying the town of Paradise. It was also its 16^th largest fire burning 153,000 acres. It was ignited by a faulty power grid during a strong Diablo wind event. Similarly, based on weather data from nearby Chico CA, maximum temperatures were higher in the 1930s.

Trend in maximum summer temperature for California's deadliest Paradise/Camp Fire

The Mendocino Complex Fire was California’s largest fire (since 1932). In July of 2018 it burned 459,000 acres. The source of human ignitions is still under investigation. Still, those fires were centered around the town of Ukiah which also reveals a cooling trend since 1930.

Trend in maximum summer temperatures for California's largest fire

In October 2017, the wine country’s Tubbs Fire was the 4^th deadliest. It only burned 37,000 acres but high winds drove embers into the dwellings of the heavily populated outskirts of Santa Rosa. Again, global warming was irrelevant as Santa Rosa has experienced a cooling trend since the 1930s.

 

Trend in maximum summer temperature for deadly Santa Rosa/Tubbs fire

Still some people are determined to link catastrophic fires with climate change. So, they will suggest delayed autumn rains allow more late season ignitions or the fall fires to burn longer. In Williams and Abatzoglou’s abstract they claim, “In fall, wind events and delayed onset of winter precipitation are the dominant promoters of wildfire.” But their results found, “no all‐region trend in onset of winter precipitation or October–November wet‐day frequency during 1915–2018.” As illustrated below by the October precipitation data for Santa Rosa, since 1900 there’s a 10% chance no rains will fall in October. Furthermore, October experienced more zero rainfall months in the early 1900s. A global warming caused delay in autumn rains has not yet been detected.

So, doing my best Greta Thunberg imitation, I say to climate alarmists, “How dare you misrepresent the causes of wildfires. How dare you imply less CO₂ will reduce human ignitions and reduce surface fuels and the spread invasive grasses. Bad analyses lead to bad remedies! Your bad science is stealing Californian’s dreams and your false remedies distract us of from the real solutions. Young people and old alike, must demand better science and better journalism!”

October precipitation for Santa Rosa, CA

Jim Steele is Director emeritus of San Francisco State’s Sierra Nevada Field Campus and authored Landscapes and Cycles: An Environmentalist’s Journey to Climate Skepticism

Contact: naturalclimatechange@earthlink.net 

Why Worse Wildfires? Part 1

What’s Natural?

published in the Pacifica Tribune, November 20, 2019

Why Worse Wildfires? Part 1

SAGE GROUSE LEKKING

There are several theories trying to explain the recent uptick in wildfires throughout the western USA. Some scientists blame increased human ignitions. Others suggest accumulating surface fuels due to a century of fire suppression. Others argue landscape changes and invasive grasses have amplified the amount of easily ignited vegetation, while still others blame climate change. What’s the Sage Grouse connection? Like human communities, the Sage Grouse’s habitat is being threatened by fast spreading wildfires, and that increase in bigger wildfires in sagebrush country is due to invading annual grasses, like cheatgrass.

Historically hot dry sagebrush habitat rarely burned (just once every 60-100 years) because slow growing, patchy sagebrush only provides scant surface fuels incapable of supporting large and frequent fires. But the invasion of introduced annual grasses, like cheatgrass, has changed all that. As one wildlife researcher lamented, “The color of Nevada has changed from a sagebrush silver gray to a cheatgrass tawny brown since the 1990s”.  Likewise, in the 1800s California’s hills were covered with perennial grasses that stayed green during the summer. Now California’s hills are golden brown as highly flammable annual grasses have taken over.

Cheat grass-dominated sagebrush habitat now burns every 3-5 years, up to 20 times more frequently than historic natural conditions. Extensive research on the effects of cheat grass found habitats with high cheat grass abundance are “twice as likely to burn as those with low abundance, and four times more likely to burn multiple times between 2000-2015.” What makes cheatgrass such a problem?

Invading annual grasses germinate earlier in the season and deprive the later-germinating native grasses of needed moisture. These foreign grasses die after setting seed, leaving highly flammable fuels that can burn much earlier in the year and thus extend the fire season. Eleven of the USA’s 50 biggest fires in last 20 years have been in Great Basin sagebrush habitats, where invasive cheatgrass is spreading. Nevada’s largest fire was the 2018 Martin Fire. Rapidly spreading through the cheat grass, it burned 439,000 acres, a burned area rivaling California’s largest fires in recorded history. 

Cheatgrass in Juniper Woodland

The 2012 Rush Fire was California’s 4^th largest fire since 1932, burning 272,000 acres of sagebrush habitat in northeastern California. It then continued to spread burning an additional 43,000 acres in Nevada. The 2018 Carr Fire was California’s 7^th largest fire and threatened the town of Redding, California. It started when a towed trailer blew a tire causing its wheel rim to scrape the asphalt. The resulting sparks were enough to ignite roadside grasses. Grassfires then carried the flames into the shrublands and forests, where burning grasses served as kindling to ignite less-flammable trees. Likewise, grasses were critical in spreading northern California’s biggest fires. In southern California, as humans ignite more and more fires, shrublands are being converted to more flammable grasslands.

Wildfire experts classify grasses as 1-hour fine fuels, meaning dead grass becomes highly flammable with just one hour of warm dry conditions. When experts estimate impending fire danger, they calculate the extent of a region’s fine fuels to determine how fast a fire will spread. The amount of small diameter fuels like grasses that can dry out in an hour, as well as twigs and small branches that dry out within 10 to 100 hours of dry weather, determine how fast the winds will spread a fire. It does not matter if it was wet and cool, or hot and dry during previous weeks or years. Just one hour of warm dry fire weather sets the stage for an explosive grass fire. Decades of climate change are totally irrelevant.

Some scientists point out that certain logging practices also spread “invasive grasses”. For that reason, California’s Democrat congressman, Ro Khanna, has been arguing that the U.S. Forest Service policy to clear cut after a wildfire is making California’s forest fires spread faster and burn hotter by increasing the forest floor’s flammable debris. Khanna warns, “Because we don’t have the right science, it is costing us lives, and that is the urgency of getting this right.” 

Bad analyses promote bad remedies and blaming climate change has distracted people from real solutions. The “cheatgrass” problem will continue to cause bigger fast-moving fires no matter how the climate changes. But there are several tactics that could provide better remedies. Holistic grazing that targets annual grasses before they set seed is one tactic. Better management of surface fuels via prescribed burns is another, as well as more careful logging practices. And re-seeding habitat with native perennial grasses or sagebrush could help shift the competitive balance away from cheatgrass. In combination with limiting human ignitions, (see part 2), all those tactics may ensure healthy populations of Sage Grouse living alongside safer human communities.

Jim Steele is Director emeritus of San Francisco State’s Sierra Nevada Field Campus and authored Landscapes and Cycles: An Environmentalist’s Journey to Climate Skepticism

Contact: naturalclimatechange@earthlink.net 

Setting Senator Whitehouse Straight on Climate & Wildfires

 

This is the transcript for the video Setting Senator Whitehouse Straight on Climate & Wildfires

https://www.youtube.com/watch?v=07juDXNa72M

Not enough politicians are honestly educating the public about the science of climate change and wildfires.

Senator Whitehouse has pushed climate misinformation mostly offering conspiracy theories that argue skeptical science is fabricated & paid for by the dark money of fossil fuel companies. He compares skeptics to a “ventriloquist’s wooden painted dummy" and controlled by fossil fuel companies. In his numerous "Time to Wake Up" speeches, senator Whitehouse has fear mongered wildfires as evidence of a climate crisis, such as highlighting Colorado’s most destructive Marshall Fire.

Now as the chairman of the senate's committee on the budget, he pushes speculation on the extreme cost of climate change. This March 9th 2023 his committee focuses on wildfires.

I was being considered to be one of the expert witnesses for that hearing but did not make the final cut. So, instead I’ll present what I had prepared for broader public consumption. I'm an ecologist and environmentalist, free of any fossil fuel manipulation, so I’m titling my contrasting presentation "Time to Learn Some Science".

There is no evidence supporting claims that rising CO2 and global warming increases the spread or intensity of wildfires. The intensity and spread of the destructive Marshall Fire was governed by the flammability of the grassland and the winter winds.

In winter, the vegetation is dead or dormant, so moisture content reaches its seasonal low.

The Marshall Fire was a grass fire. Grasses become highly flammable in just hours of dry weather. Grasses become highly flammable independent of climate change. The Marshall Fire was not evidence of a climate crisis!

The Marshall Fire was ignited by humans.

Human ignitions have expanded fire season into the coldest seasons, making deadly fires less predictable. Natural lightning fires are more predictable in the summer months of the more limited lightning season.

Like the Marshall Fire, humans caused California's most deadly fire, the Camp Fire, due to faulty electrical apparatus in October. Also in October, faulty electrical caused California's 4th most deadly fire, the Tubbs Fire.

Electrical sparks ignited California's 2nd largest fire, the Dixie Fire as well as its 9th largest, the Thomas Fire. A mere spark from a stake hitting a rock in a grassy pasture ignited a section of the 3rd largest fire, the Mendocino Complex Fire. An escaped campfire caused the 12 largest, the Rimm Fire And a highway accident caused the 14th largest, the Carr Fire.

As grass fires are want to do, the Marshall Fire went from ignition to an out-of-control state in less than one hour

Despite strong winds, temperatures were below freezing, and relative humidity was above average, conditions not considered to be worrisome fire weather. So, the National Weather Service did not issue a red flag warning that day.

However, the drying Chinook Winds were strong enough that a no-burn restriction was rightfully issued. Strong winds will carry an escaped fire into human habitat with devastating speed.

California's Santa Ana & Diablo winds have similarly spread California's worst fires. All these winds peak in winter as cold air flows down the mountains. Any global warming should reduce these winds.

Fires require high amounts of energy to ignite and spread.

It is well proven that increasing CO2 from burning fossil fuels adds about 2.4 W/ m2 of energy. But that cant ignite even a paper fire.

In contrast,  3,400 W/m2 will ignite grassy vegetation in seconds.

It is also well proven that grass fires emit about  35,000  W/m2 of energy.

 Depending on the vegetation density, that's 10 times more energy than what's needed to sustain a grass fire.

Thus, the added energy from CO2 adds only 0.007% to the energy that a fire emits So, the added energy from CO2 is insignificant regards the drying and spread of a fire.

Once a grass fire ignites a house, the house generates so much heat its ignites neighboring houses causing a fire siege that destroyed this whole community. Studies of burning furniture find a burning mattress alone releases nearly 4 million watts of heat.

In contrast to Whitehouse's call for a CO2 safety zone, a defensible space is created only by removing any vegetation that carries a fire too close to one's home. Only then can a reasonable wildfire safety zone be realized.

The introduction of Eurasian cheat grass over 100 years ago, has enabled increased fire ignitions and created more pathways carrying fire into shrubland, forests and rural towns. Cheat grass creates a dense carpet of highly flammable fuel that dies and dries by June and cheatgrass' spread is one correlate with the disproportional number of fires in the west.

If the senator wants to minimize deadly fires, the budget committee should consider more support for restoring native vegetation.

The deep rooted, native perennial grasses that cheatgrass replaced, produce moist live foliage through august and create a mosaic of grassy clumps and bare ground that slows the spread of fires.

Similarly, in forest habitat, money would be best spent increasing prescribed burns and forest thinning to create a mosaic that again reduces wildfire spread.

Fires were far more common in the early 1900s when CO2 was lower and temperatures were cooler as demonstrated by the Oregon Department of Forestry. Likewise, fires were far more common throughout the American southwest during the Little Ice Age.

Fire suppression policies that began 100 years ago and were meant to save forests, instead caused forest fuels to accumulate, unintentionally resulting now in more intense and devastating fires

Lightning is the cause of natural fires. Despite a lightning strike raising air temperatures by 50,000 F, a strike usually doesn’t ignite living trees due to the trees' high moisture content and the lightning's short duration. Lightning is also less likely to start a fire when accompanying rainstorms.

Interestingly, California accounts for 31% of all of America's burnt area from lightning, despite having one of the lowest densities of lightning strikes.

However dry lightning is more common in the arid western USA and is another correlate explaining the disproportionate number of fires in the western USA.

Accordingly, California's largest fires were due to a summer swarm of dry lightning strikes in 2020. Dry lightning caused California's all time biggest recorded fire, the August Complex Fire, in addition to causing the 4th and 6th largest fires.

In contrast, Florida is hit by 50 times more lightning strikes per square mile. Yet, although California is just 3 times larger, California's burnt area is 20 times larger than Florida's, despite both states being equally affected by rising CO2.

This difference correlates with the fact that California has the least amount of summer precipitation during lightning season while Florida has the most. Thus, it's California's Mediterranean climate that makes it naturally prone to dry lightning, drier fuels, and larger wildfires.

A Mediterranean climate's dry summers happen each summer because a clockwise-spinning high pressure system sets up and diverts moisture-carrying storms northward & away from California inhibiting its summer rainfall.

Although a similar high pressure sets up in the Atlantic, the same clockwise spin drives more rain into the Gulf and east coasts, explaining why the eastern USA has far fewer fires.

The Pacific high-pressure system fades in winter allowing California to receive more rainstorms, but La Nina-like oceans can maintain higher pressures during the winter, resulting in more drought, particularly in California.

La Nina's are natural. So, CO2 driven models have failed to accurately simulate their occurrence. Scientists are struggling to understand why their models predicted more El Nino-like oceans as CO2 increased, in contrast to the past 40 years of observations finding the pacific has become more La Nina like.

Finally, climate alarmists and mis-informers have been cherry-picking & weaponizing the tragedies of the Marshall Fire & California's fires, as evidence of global warming catastrophes. However, the global burnt area declined by 25% between 2000 and 2017, again contrary to global warming predictions.

The red areas show where burnt areas have significantly increased, blue significant decreases. All the white areas represent NO trend and reveal neither the USA nor the world show any indication of a growing wildfire crisis or any correlation with rising CO2.

So, indeed wake up America, it is time to learn some science!

Thank you

part 2: National Public Radio’s Misinformation on Wildfires and Climate

In 1994 the Harvard Business Review insightfully wrote, “The news media and the government are entwined in a vicious circle of mutual manipulation, mythmaking, and self-interest. Journalists need crises to dramatize news, and government officials need to appear to be responding to crises.” So it’s no surprise that NPR headlines hyped, Climate Change Is Driving Deadly Weather Disasters From Arizona To Mumbai claiming, “Heat waves. Floods. Wildfires…We know that climate change is to blame.” Nor is it surprising that the New York Times wrote, “climate change is a key culprit” for the American west’s wildfire disasters. And right on cue, the Intergovernmental Panel on Climate Change warns “It’s code red for humanity”. But governments promise to fix the “crisis” by controlling your energy and social policies.

Is the media honestly following the science, or once again engaging in “mutual manipulation, mythmaking, and self-interest”?

We ecologists know that wildfires and climate change are extremely complex issues with many contributing variables. Bigger, more intense, and more frequent wildfires and a longer fire season are similarly produced by different variables. Distinguishing the “key culprit” is not as easy as a NY Times’ opinion suggests. Thus, ecologists are trained to maintain multiple working hypotheses to determine which hypothesis best fits the evidence. This scientific process has grave social importance. Wrong analyses always produce wrong remedies, and bad remedies can be worse than the problems they seek to fix. So here are some major competing hypotheses explaining recent upticks in wildfires.

1. Wildfire Suppression

In the 1800s the western USA landscape was a mosaic of open meadows and patchy forests. That mosaic was maintained by frequent wildfires, either ignited naturally or by native Americans. The patchy mosaic created natural fire breaks that prevented the spread of megafires. Frequent fires also reduced both ground fuels that cause more intense fires and ladder fuels that carry fire into the canopies. All wildfire experts agree the policy of wildfire suppression from 1900 to 1970 allowed a) the explosive accumulation of ground fuels and ladder fuels and b) reduced patchiness which allowed fuel continuity across larger swathes of forests. The increase in wildfires since 1970 coincides with the relaxation of fire suppression policies when ecologists emphasized that low-intensity frequent fires are needed to maintain forest health and biodiversity.

A US Forest Service report provides photographic evidence of the landscape patchiness in 1909 before wildfire suppression began versus the increase in ground and ladder fuels and dense connected forests that evolved by 1979 due to fire exclusion.

2. Human Ignitions

Since 1900, California’s population increased from 1.5 million people to more than 39 million. More people inevitably produce to more accidental ignitions. Eighty-four percent of all USA fires are ignited by people. A larger population also requires a larger electrical grid. California’s 2nd largest fire (Dixie) was ignited by an electrical spark, as was the deadliest ever Camp fire and the 4th deadliest Tubbs fire. Three of California’s largest fires (Mendocino, Rim, & Carr fires) were caused by other human accidents.

While the natural fire season, ignited by lightning, extends from May through September, peaking in hot and dry July, human ignitions extend the fire season throughout the entire year. In California this is especially dangerous, as ignitions during the winter are rapidly spread by fierce Santa Anna and Diablo winds. These winds begin to ramp up in October as increasingly cold seasonal temperatures in the high mountain deserts push dry air down across California towards a relatively warmer Pacific Ocean. A downed powerline in December ignited a fire spread by the Santa Ana winds that devastated southern California with its 8th largest fire (Thomas Fire). California’s 4 deadliest fires, Camp, Griffith Park, Tunnel, and the Tubbs wine country fires were all rapidly spread by October and November winds. The 2nd deadliest Griffith Park fire was accidentally started in October 1933.

3. Altered Grasslands

Grasses and shrubs produce small diameter “fine fuels” that rapidly dry within 1 to 10 hours of dry weather. As discussed in part 1, those 1 hour fuels are highly flammable even during freezing temperatures and easily ignited. As seen in Fig 3. (from Keeley, 2015) grassland fires account for the largest burnt areas. Some fire experts argue the tremendous drop in wildfires during the early 20th century was not only due to fire suppression policies, but severe overgrazing that reduced the grasslands ability to spread fire. Similarly, a recent NASA report determined wildfires globally had “declined by 24 percent between 1998 and 2015.” They attributed this global decline to a change in landscapes across the African savannahs. Before, to support grazing, fires had been intentionally set to keep grasslands free from invading shrubs and trees. As villages and homes intruded into the savannah and cultivation of permanent crop fields replaced grassland, the use of fire was reduced.

In 1992, ecologists from UC Berkeley and Stanford University wrote the seminal Biological Invasions by Exotic Grasses, the Grass/Fire Cycle and Global Change. Grasses create conditions that favor fire by producing a “microclimate in which surface temperatures are hotter, vapor pressure deficits are larger, and the drying of tissues more rapid than in forests or woodlands.” An invasion of alien grass species “provides the fine fuel necessary for the initiation and propagation of fire. Fires then increase in frequency, area, and perhaps intensity. Following these grass-fueled fires, alien grasses recover more rapidly than native species and cause a further increase in susceptibility to fire.” This cycle had been well known to land managers who seeded alien grasses to increase fire frequency and intensity to suppress woody species.

The grass/fire cycle has altered landscapes across the world. In Hawaii alien grasses thoroughly filled the spaces between native shrubs, providing continuous layers of fine fuel. Prior to a 1960’s invasion, only 27 fires were recorded in 48 years, each burning an equivalent of 8 football fields. In the 20 years following invasion, twice as many fires ignited each burning an average of 400 football fields. In western North America the invasion of cheat grass increased the frequency of fires in Idaho shrublands from once every 60-110 years to every 3-5 years. In eastern Oregon land dominated by cheatgrass is considered 500 times more likely to bum than other landscapes. 

In the Great Basin deserts, due to low fuel abundance, sagebrush ecosystems burned just once every 60 -100 years. Now cheat grass-dominated sagebrush habitat burns every 3-5 years, up to 20 times more frequently than historic natural conditions. Eleven of the USA’s 50 biggest fires in last 20 years have been in Great Basin sagebrush habitats, where invasive cheatgrass is spreading. Nevada’s largest fire was the 2018 Martin Fire. Rapidly spreading through the cheat grass, it burned 439,000 acres, a burned area rivaling California’s 4th largest fire in recorded history. Additionally, a greater frequency of fires due to the combination of the grass/fire cycle and increased human ignitions has caused large areas of California shrublands to convert to grasslands.

4. Natural Climate Cycles

Most media, like the NY Times, seek out the researchers whose research focuses on finding a connection between a climate change crisis and wildfire crises. So typically the media quote Park Williams, John Abatzoglou, Daniel Swain, or Kevin Trenberth. Park Williams summarizes, “This climate-change connection is straightforward: warmer temperatures dry out fuels. That statement is true, but so is the converse. Drier conditions also dry out fuels and raise temperatures. So, blaming warmer temperatures maybe the tail wagging the dog. Furthermore, it is bad science to apply a 2°F rise in global temperatures to the measured local temperatures where fires ignite. In the USA, 36% of the weather stations with 70+ years of data report cooling trends. It’s also bad science to use average daily temperatures. Rising minimum temperatures are associated with growing populations and may still be below the dew point which would moisten ground fuels. It’s the maximum temperatures that dry out fuels.

For example, in the region of the huge Mendocino-Complex fire, which was accidentally ignited in dry grasses, annual maximum temperatures have cooled since the 1930s as recorded in the US Historical Climate network. Cooling maximum temperatures holds true throughout northern California.

Contrary to Williams’ suggestion, dryness does not depend on temperature as witnessed by the warm wet tropics or cold dry tundra. The Sahara Desert was driest during the depth of the Ice Age but converted to the moist Green Sahara as temperatures warmed. Dry conditions are mostly a function of how atmospheric circulation transports moisture from the oceans to the land, and its atmospheric circulation that makes the American west so dry and the eastern USA so moist. The most important modulator of that circulation is the natural El Nino cycles (ENSO) and the Pacific Decadal Oscillation (PDO) that shift rains and drought northward and southward. Researchers found “combined warm phases (positive PDO during El Nino) co-occurred with large fires in the central and northern Rockies, while the combined cool phases (negative PDO during La Nina) appeared to promote large fires in the southern Rockies. Almost 70% of large fires in Rocky Mountain National Park burned during La Nina events that coincided with a negative PDO, although these phases co-occurred during only 29% of the 1700-1975 AD period.”

Appropriately, the recent uptick in forest fires coincides with the natural 21st century shift of the PDO to its negative phase and the increased frequency of La Nina conditions. This natural cycle of droughts and fires forced Williams to find a narrative that synthesized the scientific evidence of La Nina effects with modeled speculation of a climate crisis induced wildfires. In 2014 Williams wrote, “The southwestern United States (SW) experienced extreme drought in 2011, related at least in part to a La Niña event in the tropical Pacific Ocean. The 2011 SW drought event was accompanied by record breaking total burned and record-size ‘‘megafires’’ in the forests of eastern Arizona and northern New Mexico.” He then conflated model myth-making writing, “Model projections developed for the fifth phase of the Coupled Model Intercomparison Project suggest that by the 2050s warming trends will cause mean warm-season vapor pressure deficit to be comparable to the record high VPD (dryness) observed in 2011.

But climate models have done an extremely poor job of modeling drought. Michael Wehner published the graph below, which was also featured in a National Climate Assessment. The observed (red) Fractional Extreme drought area over the USA and Mexico was clearly greatest during the 1930s and attributed to landscape changes and natural cycles. The second worse drought extent occurred in the 1950s. Although modelers already knew the results, their CO2 driven model results (blue) failed to even hint at those historical droughts and accompanying heat waves. All the climate models could do is project imagined disasters in the future. Rarely does the media mention the grass/fire cycle, or the dryness of ENSO cycles. Instead, NPR prefers to blame climate change for worse wildfires The media is indeed stuck in the “vicious circle of mutual manipulation, mythmaking, and self-interest”