Also, most people apparently don't understand the distinction between "wildfire" and "firestorm". Since upwards of 97% of wildfires are actually human-caused these days, of course a human has to be present for that to happen. No humans means far fewer wildfires.
But a lot of what we've been seeing lately are actually firestorms, where a single structure catches fire and then that spreads uncontrollably to the next structure and so on until everything flammable is basically burned out. Firestorms happen because there are few if any resources available to put the fire out while it's still small. So while the original source of ignition may very well have come from a wildfire, the firestorm can keep burning and spreading long after the wildfire itself has basically played out, at least in that immediate area.
And no, climate change has little or nothing to do with this.
I agree - controlled burns are effective at keeping brush at manageable levels, and fire is a natural part of the forest ecosystem. And part of California’s climate. Developing too close to the wilderness edge is putting more human lives at risk. (I own farm and forest land, and am involved in conservation and restoration; I’m familiar with the challenges.)
But Climate Change is rapidly becoming the dominate factor for one simple reason: hot, dry, things burn. And Climate Change is making things hotter and drier.
Physical wetness, though, may make quite a bit of difference, especially when it comes to a fire actually igniting to begin with. But even that may not matter so much when it comes to things like lightning strikes, which may be in the tens of thousands of degrees.
So, for example, if the temperature might normally be 70F but instead is closer to 100F, that small difference is minimal compared to the temperature of any flames. But it might make a huge difference to someone fighting those flames, unless maybe they are right in the thick of them.
Which means we don't have the basis for saying that what's been happening in California over the past couple of decades is an emergency. It might just be part of the long term cost of choosing to live in California.
Yes, climate fluctuates. Yes, there have plausibly been years of drought and fire in centuries past that would rival recent years. But absent the specific data you say is lacking, if you believe that climate science is generally correct, then more drought, more warming, more fire is the obvious trend. Not just California, but the entire world.
Regardless of whether similar events have happened in the past, there’s an obvious reason for the dramatic uptick between the 1970s and today: CO2 in the atmosphere, put there by humans.
The fact that this reason is "obvious" doesn't mean it's correct. Climate models based on the assumption that human CO2 emissions are the primary cause of warming have been significantly over-predicting warming. So I don't think we can say human CO2 emissions are the primary cause. We are still too uncertain about how the climate works for that.
...or it could be because the forests are so out of balance because they need fire to thrive that smaller events have oversized effects.
Before people started blaming severe forest fires on climate change they blamed the fires on the policy of systematically putting out all fires which allowed fuel to pile up on the forest floor allowing them to burn much hotter resulting in the trees dying. Before this policy the fires would just burn through the underbrush and the trees would survive as this is how they evolved.