Direct Causes of Wildfires

I’m sure you’ve heard by now that climate change is making wildfires worse. Large areas of forested land subjected to drought conditions are dry and brittle. Average wind speeds are increasing around the globe. And the number of storms that produce lightning strikes also seems to be increasing. The impact of this triple threat can be seen most in the western United States and across Canada.

The slideshow has two images you can toggle between for comparison. They both show the same area in Quebec, which has been contending with an unprecedented number of wildfires this year. This NOAA satellite view shows a massive lightning storm in the first slide, and in the second slide 24 hours later you can see numerous wildfires that were ignited by that lightning.

Truth be told, lightning causes only a small percentage of wildfires in the US. Here’s what the stats look like for a small range of years, but it holds pretty consistent over time. But the recent increase in lightning-caused fires in recent years has moved that category from 1.8% to over 10%.

Because lightning strikes often occur in remote rugged areas, it’s difficult to get manpower and equipment in to suppress those fires. Dropping water from the air can help, but is never a full solution. Some wilderness fires occur too far from airports and/or water sources for air drops to be a viable option. Note this is data for the US. Globally, lightning causes around 12% of wildfires.

Ironically, the increased severity of wildfires has a detrimental feedback effect on global warming. Scientists estimate 1.76 billion tons of CO2 was released from burning forests in North America and Eurasia in 2021. That’s a significant fraction of the global CO2 emissions total, which for that same year was 37 billion tons. And wildfires are happening in the southern hemisphere as well, but (except for those in the Amazon) they tend to get less media coverage.

Trees store a lot of carbon, and when they burn or decay, that carbon is released back into the atmosphere in the form of CO2. When wooden structures burn the same thing happens. This increases global warming, leading us back to the triple threat explained in the first paragraph. And so (unfortunately) it goes.

One final note: Contrary to what you may have heard, there is no evidence that satellites operated by secret elite organizations are starting wildfires intentionally by firing laser beams down from space. 🙂

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7 comments on “Direct Causes of Wildfires”

  1. The data in the pie chart appear to be from North Carolina.

    The portion of fires that are lightning caused varies around the world.

    This research paper says, “Lightning-caused wildfires account for a majority of burned area across the western United States.” and “Lightning ignited 40% of the reported wildfires and accounted for approximately 69% of the total area burned across the western US from 1992 to 2013, albeit with distinct geographic variability.”

    1. Thanks for the additional info Cindy. I figured the % causes would vary by location, but didn’t want to get into that much detail. The pie chart is clearly credited to I just wanted to give a general impression of the range of causes for wildfires. Many locations are biased by specific factor. For example, in my home state of AZ, “equipment caused” fires are way higher than the 3.7% cited by NC. It’s hard to find exact numbers, but read what they say here:

      1. Dan Heim,

        Heavens, yes! Dragging safety chains cause a lot of fires along interstates in the West–yikes! I’m glad the paper looked at fires West-wide.

        Cindy Salo

  2. btw the window you have selected is over 20 years old that introduces an element of skepticism in this old retired forester! I’ll look into my sources.

    1. Agreed. But I just needed a good pie chart breakdown of wildfire causes. At least it was clearly labeled “1997-2002” so as not to mislead. And as I noted, the number of lightning-caused wildfires is indeed increasing. Follow that 10% link for some more recent stats.

  3. no evidence that satellites operated by secret elite organizations are starting wildfires intentionally by firing laser beams down from space.

    aww the most obvious cause eliminated … laser thinking imho

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