California Wildfires

With the devastating wildfires terrorizing California, climate deniers are doing everything they can to try to persuade people that it’s no big deal, and even the big deals have nothing to do with man-made climate change. To believe them, you have to believe some ridiculous things — like the notions that hotter temperatures and more drought have nothing to do with wildfires.

Nobody serious claims that the explosion of wildfire disasters is only about climate change. Yes, there are more people living in vulnerable areas. Yes, forest management has a big effect. But the climate deniers want you to think that’s the whole story, that climate change is irrelevant. To believe that, you have to believe that temperature and drought are irrelevant.

Do you believe that?

California has been warming rapidly; since 1975, temperatures have been increasing at about 5.5°F per century, and they’re already 3.1°F hotter than they were in 1895. Summertime temperatures have been rising even faster; since 1975 they’re going up at 7.2°F per century.

Summertime high temperatures are also on the rise:

And, so too have summertime low temperatures:

But … to listen to the climate deniers, this has absolutely nothing to do with wildfire risk.

Much of California, especially the south coastal region, has been in drought for years. It’s part of a disturbing trend, revealed by the Palmer Drought Severity Index (“PDSI”). Note that negative values indicate drier conditions (drought), positive values indicate wetter conditions:

It fluctuates a lot, but if we smooth the data we reveal the trend, which has lately plunged into the most severe persistent drought on record:

But … to listen to the climate deniers, this has absolutely nothing to do with wildfire risk.

Rainfall and temperature aren’t the only factors influencing drought. Much of the water cycle is assisted by snowfall, which accumulates in mountainous regions during winter and is slowly released to the land when the snow melts during spring and summer. Unfortunately, this crucial water reservoir is on the decline in California. Here’s the amount of snow-water equivalent in the Sierra Nevada mountains of California on April 1st (a bellweather date), as a fraction of the long-term average value:

Note that reddish colors mark less-than-average snowpack, blueish colors more-than-average. Note there aren’t any blueish colors.

But … to listen to the climate deniers, this has absolutely nothing to do with wildfire risk.

Do you really believe that higher temperatures, more severe drought, and reduced snowpack have nothing to do with wildfire risk and severity? That’s what you have to believe to buy the story from climate deniers.

CalFire staff, the firefighters who are on the front line, they believe that climate change does contribute to the increased wildfire problem. A lot.

But not the climate deniers. It’s easy for them to believe idiotic notions about heat and drought having nothing to do with wildfire risk. But then, unlike California firefighters, they’re not the ones who risk and sometimes lose their lives protecting others.

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25 responses to “California Wildfires

  1. Let the deniers pay for (all) the damage then, if it’s no big deal.

  2. we made a trip down to Susanville from Puget Sound and saw a lot of dry forest and grasslands that looked ready for firestorm. Pretty ugly. I was reading that the Trumpsters around the Carr fire have not yet been convinced that AGW is real. That is an interesting demonstration of tribalism overwhelming logic. Trump said, don’t believe what you see or read. His fans think that’s good advice. Too bad that stupidity is not inherently and immediately painful, no essential hot stove experience with some manifestations of stupidity and tribalism. Too bad about that.

    • @smallbluemike,

      On a trip in July to Acadia National Park on Mt Desert Island in Maine, I was impressed with the weather run-up to 1947 fire which decimated much of the Park and similar fires elsewhere in Maine. According to the history, Winter and Spring had been relatively wet, but, then, Summer became extraordinarily hot and dry. It was enough to dessicate a lot of collected fuels, and something (believed to have started in a bog?) set it off. Then, whipped by winds, it tore across the Island. The winds reversed and it tore back.

      What this might suggest is that extremely dry conditions and very hot weather, such as might be expected with global warming, even if short-lived, can set a place up for real fire damage, even if the Spring and Winter are wet.

      I don’t know sources of numbers about how quickly forests can dessicate given prolonged heat and low humidity.

      • I would expect that in climates with winter rainfall and summer drought, where most plant growth happens in the winter part of the year because growth is limited in summer by lack of water, wetter winters could well result in higher fire risk. Especially if winters are warmer as well as wetter, as they are likely to be as the world warms.

        Vegetation will grow more over the winter so there will be more fuel, then as the dry summer comes it can turn to a tinderbox.

      • Ed, I believe that is exactly what happened in California this year.

      • Whachamacallit

        Huh, so Maine summers are indeed getting hotter and drier? I went to Maine for college a few years ago, and never stayed in the summer. But my best friend back in college was born and raised in the state, and he did say anecdotally that it seemed that late springs especially were getting drier.

    • I know what you mean (having had a literal ‘hot stove’ moment at the age of 4–I don’t have much recollection of it, but my mother reported me crying out repeatedly “Now I know! Now I know!”) Anyway, it is too bad in a way that the feedback doesn’t work more directly and helpfully. As pointed out on the other thread, there can even be moral hazard built in by regulation or the structure of insurance, whereby risky behavior is actually incentivized.

      On the other hand, while I’m not sure how much help it is to society at large in structural terms, it’s at least cheering when you see folks being proactive like this:

      I’m disappointed for the new UUVC, however, that they haven’t managed to unload the old place after all; things looked good for a while in that regard. But maybe they can find someone in thoroughgoing denial who also has deep pockets. How hard could that be? ;-)

  3. Reblogged this on Don't look now and commented:
    Increased wildfires omitted from climate models:

  4. Another scapegoat that has been invoked to ‘explain’ the wildfires in California, Greece, and elsewhere, are arsonists.

    I don’t doubt there are maliscious sociopaths who set fires deliberately and negligent idiots who light fires in inappropriate locations, including power companies with badly maintained power lines.
    But in previous decades without the hot, dry conditions those fires may have burned out a hillside, and then petered out.

    It is the abundance of dry fuel and current climate that turns what otherwise might have been a limited local event into a rapidly spreading major conflagration.

    • @izen,

      And, back in the day, I presume the incidence of careless smokers and campers with campfires was higher as well.

    • “Another scapegoat that has been invoked to ‘explain’ the wildfires in California, Greece, and elsewhere, are arsonists.” There are groups on Facebook that are claiming that THEY are doing it with ‘directed energy weapons’. Anything other than facing a painful reality, I suppose.

  5. As an Australian living in a rural region with high bushfire risks I have noticed significant impacts of warmer winter conditions on fire risk management; dry evenings suitable for controlled burning to reduce fuel loads are less often leading to mornings with heavy dew. This is very significant, as that dew acts as a fire suppressant and in the past was a reasonably reliable way to have such fires (esp. areas of grass) extinguish themselves or for remaining fires to be slow burning and readily extinguished with little labour.

    More vigilance, more people, more equipment is required to do this fuel load reduction safely because of warmer winter conditions. The window of opportunity to use fire during cool times as a primary means of reducing risk in the hot times is, in my experience, shrinking. The consequence are ultimately flowing through to hot weather ‘fire season’ – which is longer and more likely to include extreme heatwaves as well.

    • @Ken Fabian,


      Mt Desert Island in Maine is fortunate because it is relatively small, accessible, and contained. Their plan for dealing with a repeat of 1947 is to be extremely vigilant, and descend upon a fire breakout with overwhelming force in order to contain it. Clearly, this does not generalize to much larger areas.

      On the other hand, they have accepted that controlled burns cannot be done on Mt Desert. These themselves can get out of hand. I know of one which was started on Martha’s Vineyard off the Massachusetts coast (3 miles from Woods Hole, if that), and it almost did get out of control, due to a wind change.

      • The potential for controlled fuel reduction fires to breakout is very real – as I said, I think warmer conditions increase the difficulties in doing so safely. That and stronger legal actions when it does escape tends to inhibit efforts to do such burning – but the consequences of not doing it flow through to the times of highest fire risk. The scale of force needed to be overwhelming will be always be less in cool conditions than at the peak of hot weather fire risk.

        Different management approaches may work better elsewhere, with different vegetation, ecosystems, climate and infrastructure/services – Australia is at the extreme end for fire risks, but similar methods were used traditionally within North America and Africa. Traditionally there was probably widespread agreement on how, when and why – a homogeneity that does not exist in the modern context.

      • I observe the native forests of the Pac NW that are primarily douglas fir, hemlock, and a smattering of cedars and true firs and I see forests that are struggling with the impact of drier and slightly hotter weather. I believe these are not forests, like pine forests to the south, where fires can sweep through and the forests recover quickly. The duff, the ground itself, is full of combustible material in undisturbed ground, so a fire in the trees can turn into a fire on the ground that overwinter and spring back to life if it is not thoroughly extinguished. One example of such a burn in these forests is the Yacolt burn.

        The changed winter conditions that have been described here seem correct to me. We can have a significant amount of tinder-like growth over a large area if conditions are right, then a really hot dry summer can turn the winter new growth into flashy kindling. I lived in the woods here until 1994 when I decided to move to “town.” I was already concerned about building forest fire conditions in the woods at that time. The famous NW soggy weather had dried out quite a bit by 1994 as far as per my observations on the ground.

  6. I think that if you have more CO2 in the air, and lots of sun and rain, then you have ideal conditions for rapid growth of vegetation. And then when summer comes and its hot and everything dries out, you have ideal conditions to burn that vegetation. So I would expect AGW to lead to more frequent wildfires, and if you go a few years with good growing conditions and no wildfires – then to more intense fires when they finally come.

  7. Who are these “climate deniers” you refer to?
    Do you not mean “climate CHANGE deniers”?
    As far as I know, no one is “denying the climate”.
    Quite the opposite in fact.

    • Martin Smith

      The term “climate deniers” is sort of like the term “climate alarmists.” Climate deniers refer to any person who believes the results of climate science, currently summarized in the IPCC AR5 report, as a “climate alarmist.” Climate deniers often use the term “CAGW alarmist” for the same purpose. A climate denier often makes a point of saying “Of course the climate is changing; the climate is always changing,” but the climate denier always means the climate is changing naturally, not because we are burning fossil fuels. And when confronted with the science that validates the conclusion that the current global warming is caused by burning fossil fuels, the climate denier changes tack and says “There were times in the past when the temp was higher than it is now,” or “There were times in the past when CO2 was not as high as it is now but the temp was as high as it is now,” or “The Global Climate Models didn’t predict the pause.”

      • Philippe Chantreau

        The meme “of course the climate is changing, it’s always changing” is in fact relatively recent among the FUD production. For as long as they could, they held on to the “nothing is really happening” piece of BS. In fact, Anthony Watts entire circus was based on that argument. How short memories are…

      • Indeed the climate is always changing, but it’s worth pointing out to those who routinely use the ‘always changing’ argument that susceptibility of Earth’s climate to change is precisely why adding gigatonnes of CO2 into the atmosphere is so worrying, that only in a climate resistant to change does it become insignificant. (Leaving aside ocean pH effects). It’s the vehicle that won’t steer a straight line that is most at risk of running off the road.

    • @Quae Soveritas,

      That surely is nitpicking. Besides, it isn’t true. It is arguable that if someone denies the well-known mechanism for what affects climate, it is effectively the same as denying climate, for the thang they are speaking about isn’t the same as the thing studied by Science.

    • Or to be really specific, it means the people who deny anthropogenic global warming. They’ll admit to anything except that its getting warmer and we are to blame. Of course exactly what they’ll admit to changes day by day…

  8. The issue of fire danger combines several factors – availability of fine fuel (tinder) to start the fire, availability of more substantial fuel to let the fire grow, dryness of both, wind, temperature, relative humidity, recent precipitation, etc.

    The Canadian Fire Weather Index provides a good summary and evaluation of the danger factors, and is used to assess and predict current danger in real time:

  9. How about coverage and analysis of this:

    Try to imagine a world with 5 degrees of heat rise. Could this cost jobs and slow economic growth?