Lots of newspaper articles say that “wildfires are worse now than they used to be” and often say “the major part of that is due to climate change”. Logically, first we have to define “worse” before we can go on to ascribing causes. In other words, we need to be clear on “what aspects of them are worse, compared to what other time periods” before we can collect relevant data (assuming it exists) and be clear on attributing causes. So can we be more specific about what is worse? Through reading different articles and studies, we can come up with different variables possibly related to “worseness.” It should be noted that the value of the differences and the timeframe of comparison are both essential to clearly understanding the “worseness” question.
First, there are acres burned. I would argue that that does not tell us much, for at least two reasons. If we have WFU (wildland fire use) now and we didn’t used to do it, it seems logical that that this change in suppression policy would lead to increased acres burned by wildfires. Kevin and Andy have also brought up the question of whether burned area is currently accurately measured (a) and whether that can be compared to measurements from the past (in the US) (b). See Kevin’s comment here for links to the more recent data. In the last 150 years or so we have gone from (1) intentional and natural ignitions with no suppression (by Native Americans) in the western US to (2) serious attempts to get fires out all the time but perhaps without the greatest technology, to (3) great technology to put out fires, coupled with the concept of WFU to reduce fuels.
If wildfires can be good, and we are encouraging fire on the landscape through WFU, we would expect burned areas to go up. If that makes wildfires “worse” for purposes of attributing the increased acres to climate change (for example), that seems like it’s a logical problem. Burned area, in and of itself, seems like it would be a function of suppression strategies and tactics.
So people maybe don’t mean “number of acres” when they say “worse”. Maybe there’s more damage to property, infrastructure, soils and watersheds? Or the latter damage is more visible? Of course, there wasn’t as much property around in the past (not in forests or shrublands, but maybe in grasslands). And no one was measuring soil and watershed damage. So how can we compare that to the past? What people might mean is that “nowadays in some cases (most notably in California, based on the news) people are unable to suppress wildfires until they burn up housing and other infrastructure.” And the scariest thing is that there are conditions under which fires become uncontrollable, even today. What could be the differences from the past? 20 years ago? 50 years ago?
There’s also “more frequent“. Since many are human-caused, this could be because of more people being around and/or more people around behaving unsafely. Across the West, there are powerline started fires, steam train started fires (apparently, I don’t think this has been found out for sure), and military training exercise started fires, plus clueless campers and shooters who start fires. At some point, does “more frequent” mean “less attention can be paid to each individual fire” which would also allow acreages to increase?
To understand all this, we really need to interview people working in fire suppression right now, in the past, and perhaps people who study their observations in some way. To readers: in your area, are fires “worse” than the past? When in the past? How do you define “worse”? What do you think the reasons are?