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Italy wildfires encircle Palermo as temperatures hit 47C
(www.theguardian.com)
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this post was submitted on 25 Jul 2023
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Reminder that under 250-300C forests don't self ignite.
Lightning strikes or idiots are the cause. And iirc idiots lead the statistics something like 10:1
While these are more prevalent, they’re not the only causes. For example, sparks from rock falls also cause natural wildfires, as well as spontaneous combustion. The latter is caused by oxidation, bacterial fermentation and other natural processes.
Manure piles can spontaneously combust during conditions of extreme heat. Cotton and linen can ignite when they come into contact with polyunsaturated vegetable oils. Hay is quite prone to spontaneous combustion when specific moisture/heat levels are reached.
So while near densely populated areas idiots are way more likely causes, sometimes forests do self-ignite. And the rate of those events increases during heatwaves.
Spontaneous combustion like in moist haybales or as described in the article you linked, via fermentation sure does exist, not really in the wild. Like in a forest. The entire wikipedia page is about specific circumstances, none of which happen naturally.
Eg there shouldn't be any manure piles out causing wild fires. If there are, its again caused by idiots.
I dont have numbers on rock sparks causing fires but it kinda sounds exceedingly rare?
Like all of these points seem like they would be a fraction of a fraction of the causes for forest fires.
By and large, firest will not self ignite. If you see a raging fire on the news, its overwhelmingly unlikely to be anything but an idiot to blame.
Yeah, it’s definitely very rare. I can’t seem to find that article right now, but I remember reading that these events account for something like 0.1–0.3% of all wildfires. So while insignificant as an actual cause in general, with 100k+ wildfires happening each year it means that a couple of hundreds per year should still be caused by those. Which is still like one every 1-2 days on average.
Not enough to be a noticeable threat, but enough to cause a pedantic comment mentioning those as existing :)
The climate does affect the readiness of forests to ignite though, by creating drier conditions. It also increases the intensity of thunderstorms in many areas. So while the number of idiots may be constant, the dangerousness of the idiots and the number of lightning strikes are increased by climate change.
Certainly, continuous droughts dry out a forest, setting it up for am idiot (or lightning strike) to set it on fire. It's a bit of a nitpick but technically the higher temps don't necessarily make the forest more dry, but yeah climate change does include droughts and extreme weather events.