US Wildfires: Are They Really Caused by Climate Change?

There is constant talk right now about wildfires, after an orange haze covered NYC recently and “hundreds” of wildfires started around the same time in Canada. The general consensus on mainstream media is that climate change is the primary cause. But does the evidence back that up, or is our old friend the local arsonist also a significant – and growing cause – of summer fires?

Let’s dive in.


The National Interagency Fire Center has been collating reported fires in the USA since 1983. Before that there were only local fire department records, hearsay and Ol’ Man Simpson to go on. In 2022 some 7.5 million acres of land were hit by wildfires, which compares to 1.3 milion 40 years ago. The general trend for areas affected is up since the 1990s, when the average area burned was about 2 million acres. Although 1996 was exceptional at over 6 million acres.

In terms of numbers of fires in the US the all time peak was 2006, with some 96,380 fires reported. Last year there were just under 69,000. So if you choose those years as your marker points then you could argue that climate change is causing a decrease in wildfires. Assuming you believe that climate change is directly linked to wildfires.

So far in 2023 there have just under 20,000 wildfires reported, which the Agency says is below the 10 year average. So if climate change is getting worse, as in the US is getting hotter on average and receiving less rainfall in forest areas, then that is not reflected in extra wildfires.


OK let’s look back a bit. What made 1996 such an exceptional year for US wildfires, can we learn anything from that spike?

A report from the National Forest Service noted severe drought in the South Western States by mid-May that year. Strong winds were another factor in helping fires spread rapidly. August was a peak month as the dry summer weather continued and the report notes that human resources were being stretched by the sheer number and size of fires that month. In short, there weren’t enough fire-fighting crews to deal with the fires and the ground conditions were perfect for the rapid spread of fire.

Over the summer season of 1996 the Forest Service report attributes the main cause of fires as follows; 58% caused by lightning strikes, 12% by campfires not being managed properly and 9.8% deliberate arson. Interestingly some 9% of fires were defined as being caused by Miscellaneous factors. Some 1.2% were also caused by”children.” Is that junior arson, or just children building a huge campfire next to some tinder dry trees? The 9 percent figure on unknown or Miscellaneous causes is a big grey area in terms of data and it suggests that due to the intensity of some fires, the root cause was difficult to define, way back in `96.

According to the report 1996 was a low year for arson, with some 4,648 incidents recorded. The peak in the 80s was 6,483 arson cases in 1983, again a very big difference in percentage terms. So is the Forest Service data reliable as an indicator of true causation?


The intepretation of US wildfire causation data, specifically that 58% of wildfires are started by lightning – is questionable, some might say dubious.

Data from the UK Fire Chiefs Council in the UK states that about 50% of ALL UK fires involve arson. In Northern Ireland an estimated 66% of all fires are started deliberately. A study quoted in Smithsonian Magazine put the estimated percentage of wildfires caused by arson at 21%. That’s over twice as high as the stat quoted by the National Forest Service – quite a margin of error.

The situation regarding arson is complicated by the mental instability of many arsonists, plus the lack of DNA or other evidence which can be found following a major fire. This report from RFI in France notes that some pyromaniacs are volunteering to fight the fires they deliberately started, such is the rush they obtain from seeing the flames. Volunteering also gives you the chance to destroy, or contaminate the evidence at the scene too.

A scientific paper published on Science Direct looked at fires in Europe and noted that 90% of wildfires around the world are caused by human activity. The study looked at detailed data from Spain since 1988 and concluded that;

“Only 4% out of more than 230,000 fires investigated were caused by lightning, while the remaining 71% of the fires were produced by people, either by negligence (16%) or intentionally started (55%). Lovreglio et al.”


A study quoted on PNAS in 2017 stated that human activity was the primary cause of 84% of wildfires. It also noted that lightning strikes were the cause in more remote and mountainous regions of the US, where the weather conditions were ideal for “hot” lightning strikes. In other parts of the USA the human factor was driving the increase in wildfires in terms of frequency, and acres being burned.

Here’s an extract; Human-started wildfires represented 84% of the 1.5 million wildfires included in this analysis (n = 245,446 lightning-started fires; n = 1,272,076 human-started wildfires). The eastern United States and western coastal areas were dominated by human-started wildfires, whereas lightning-started fires dominated the mountainous regions of the western United States (Fig. 1Table 1 and Table S1). 

In addition the study also noted that human started ignitions were highly effective at expanding the wildfire season. So rather than wait for the weather to naturally produce long dry, humid spells, which generate thunderstorms, humans were taking the opportunity to start fires as soon as the ground was dry.

Extract; Human ignitions dramatically expanded the wildfire season in the United States, particularly during spring. The length of the human-started wildfire season [defined as the interquartile range (IQR) of human-ignited fires] was 154 d, more than triple that of the lightning wildfire season (IQR = 46 d) (Fig. 2 and Table 1). 


When we look back at scientific studies of wildfires, what we find is that human activity; negligence and arson, are common factors in the vast majority of cases. The evidence that the changing climate itself, or hot weather, is causing spontaneous combustion of trees is thin. The lightning strike theory doesn’t hold up outside of mountain regions, all the historic causation data, of 1.5 million fires, shows that.

Yet the current narrative is that the hundreds of wildfires which started at the same time in Canada were due to “climate change.” Politicians, activists and the MSM are all toeing the line on this explanation right now.

Still, some data shows the mentally ill arsonists may have had a part to play in recent events. One report from Vancouver says a woman was arrested after a string of fires were set on a forest trail recently. The Toronto Sun reports that arson investigations are underway in parts of Quebec, to see if some blazes were started deliberately.


The risk for insurers is growing when it comes to wildfires, in Europe, North America or elsewhere. As development of second homes, cabins, glamping or other forest based activities increases, it’s worth noting that this will increase the risk of wildfires. More humans interactiving with nature during hot weather means more fires; accidental and deliberate. Plus the value of assets in the way of fires has increased due to inflation since Covid.

But insurers should never lose sight of the value of hard data when it comes to causation. By buying into the climate change narrative your brand is deflected from researching and understanding the true causes of major catastrophe events. Facts don’t care about your feelings, or your policy book losses.




About alastair walker 12555 Articles
20 years experience as a journalist and magazine editor. I'm your contact for press releases, events, news and commercial opportunities at Insurance-Edge.Net

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