Climate Change IQ Question 7: Is the increase in atmospheric CO2 making wildfires worse?

Answer: No, much more forest burned in the 1930s. The recent increase compared with the 1960s through the 1980s is probably caused by poor forest management.

Northern California is being devastated by wildfires, with dozens of people losing their lives and property damage topping $3 billion. Dry conditions and wind have hampered efforts to control them. Huge amounts of pollution—10,000 tons of soot, PM2.5s (small particulates), and VOCs (volatile organic compounds)—are being released into the atmosphere. Mother Nature has no smokestack scrubbers.

Are the fires setting records? That depends on when you start your data series. The Historical Statistics of the United States—Colonial Times to 1970 shows that five times as much acreage burned in the 1930s (see the graph below). The National Interagency Fire Center only tracks data since 1960, when fire suppression efforts were going strong. The two series agree for the time when the data overlap in 1960-1970. [1] The legendary Tillamook Burn ravaged 554 square miles in Oregon in 1933.

We have far more effective fire-fighting technology than in 1930, but what has changed since 1960? An average 0.128-degree per decade temperature increase cannot explain the increase in burned acreage, especially as that was previously decreasing while temperature increased.

What has changed dramatically is forest management. As Rep. Tom McClintock (R-Calif.) explains, [2] “environmental protection” laws now prevent clearing underbrush and excess timber, making national forests far more susceptible to uncontrollable conflagrations. This year there was a wet winter and spring, with explosive understory growth, followed by a dry season and a very unusual weather event, with hurricane-force local winds and a temperature inversion.

Fire hazard was also “extreme” in 2002, when fuel loading of 400 tons of dry fuel per acre was ten times the manageable level. Then-Senator Jon Kyl (R-Ariz.) stated that 5,000 environmentalist lawsuits obstructed good management and drained the National Forest Service of Resources. A moratorium on road-building on 43 million acres made mechanical fuel removal virtually impossible, while 85 percent of national forests were said to be in poor health and prone to fire.

Arson is one of many causes of ignition—a suspect has been arrested in California—and starting wildfires is a potential terrorist method. An extremist environmentalist website (now apparently defunct) once posted a guide to setting fires using electric timers. ISIS has recently celebrated the fires and published instructions for arson attacks.

Take-home lessons:

  • Under natural conditions, wildfires are inevitable.
  • The restriction of prudent, profitable use of forest resources—called logging—has not preserved this great natural resource but greatly increased its susceptibility to destruction by natural forces, including fire, especially when exuberant new growth dries out in the summer.
  • Burning hydrocarbon fuel in the internal combustion engine did not cause the fire. But banning such engines, as California has proposed, would mean firefighting with horses and shovels: No bulldozers, power tools, or helicopters for containing the fire or rescuing victims.


1. Rucker C. Fires far worse last century. Center for a Constructive Tomorrow (CFACT); Oct 17, 2017. Available at:

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