Forest Fires -Fanning the Flames of Climate Alarm


The recent spate of horrific and deadly wildfires in California has  been accompanied by claims from proponents of catastrophic man-made  warming of a link between climate change and increasing forest fires.  There is wide acceptance among the media, “climate experts,” and the  general populace that forest fires are increasing in frequency and size  because of man-made climate change. As with drought, desertification,  and heat waves, a link between warmer weather and more forest fires  seems to be only common sense. Without deeper knowledge, one might  logically surmise that warmer, and thus drier, weather means more fires. 

The news media pumps up its ratings by broadcasting spectacular  images of forest fires, particularly when they are fatal. Reporters  regularly proffer opinions that man-made warming is to blame for the  loss of life and property.  

This is really a window into what global warming looks like. It  looks like heat. It looks like dryness. It looks like this kind of  disaster.                                                                  — Dr. Michael Oppenheimer 

Contrary to computer models that support the predictions of climate  alarmists, real-world data indicate that “experts” like Dr. Oppenheimer  are, in fact, incredibly wrong. The science and research of fire in the  northern hemisphere is quite clear, there has been a significant decline  in forest fires over the last 100-plus years and it is happening, not  in spite of rising temperatures and increasing CO2, but because of it. 

The Science Behind Declining Fires

The scientific reasoning for declining fires is twofold, but both  contribute to an increase in global soil moisture content, decreasing  the forest fire potential. Firstly, the major cause of water loss in  plants is attributable to the transpiration process in which plants take  water out of the soil and expel it to the atmosphere. Due to the CO2  fertilization effect, increasing CO2 means that the plants’ stomata are  open for shorter periods, the leaves lose less water and more moisture  stays in the soil. Secondly, rising temperatures allow the atmosphere to  increase the amount of water vapor it can carry, leading to additional  rainfall and increased soil moisture. 

This increased soil moisture has led to a “greening” of the Earth  that is easily confirmed by recent NASA satellite data. According to Zhu  (2016, Fig. 1) 25% to 50% of the planet over the last 35 years has  seen an increase in vegetation while only 4% is “browning.” 

Background on Fire – Historical Support

A voluminous number of studies on the history of fire activity support  the notion of a long-term decline of forest fires that began at the end  of the Little Ice Age (circa 1850). The National Interagency Fire Center  provides extensive information on forest fires in the United States  (NIFC 2017, Fig. 2). The data show a declining number of fires over the  last 30 years. This mere fact is certainly at odds with nearly  everything we have heard to date on the subject. 

 One of the most extensive studies on the long-term fire trends was  completed by a team of scientists with the Canadian Forest Service  (Flannigan 1998). They compared temperatures and CO2 concentration  versus frequency of forest fires over the last 150 years in North  America and northern Europe. The authors stated “We believe that global  warming since 1850 may have triggered decreases in fire frequency in  some regions and future warming may even lead to further decreases in  fire frequency." Their conclusion is powerful: “All empirical studies  have shown either a decrease or no change in fire frequency during the  20th Century.” 

Yet another landmark study in 2014 found that acreages burned  worldwide in the 20th and early 21st centuries had declined  significantly (Yang 2014 FIg. 3). The authors attributed the decline in  high-latitude forest fires, particularly in most of North America and  Europe, primarily to rising CO2 concentrations and their fertilization  effect on plants and the resulting greening of the planet and a warmer  climate that increases soil moisture. 


The media and alarmist groups tell one story while the data tell quite  another. Rather than an increase in the frequency and intensity of  forest fires, as we have heard for many years, there are fewer forest  fires, thanks to more CO2 in the air and more water vapor associated  with increasing temperatures. This is a very inconvenient fact for the  anti-fossil-fuel groups that ruthlessly exploit the tragedies of others  to raise funds for their causes. In the future, it will be very  difficult to appeal for money on the basis of forest fires when it  becomes known that more CO2 and warmer temperatures mean fewer forest  fires.


Flannigan MD, Bereron Y, Engelmark O, Wotton BM (1998) Future  wildfire in circum-boreal forest in relation to global warming, Journal  of Vegetation Science 9, pp 469–476 

HadCRUT4 (2017) The Hadley Climate Research Unit (HadCRUT4) annual  global mean surface temperature dataset, 

NIFC (2017) National Interagency Fire Center - Total Wildland Fires and Acres (1960 – 2015),, accessed 04/2017 Tans P, Keeling R, (2017) Trends in Atmospheric Carbon Dioxide. Earth  System Research Laboratory (ESRL), Global Monitoring Division, NOAA 

Yang, J, Tian H, Tao B, Ren W, Kush J, Liu Y, and Wang Y (2014)  Spatial and temporal patterns of global burned area in response to  anthropogenic and environmental factors: Reconstructing global fire  history for the 20th and early 21st centuries, J Geophys Res Biogeosci,  119, 249 263, doi:10.1002/2013JG002532. 

Zhu Z, et al. (2016) Greening of the Earth and its drivers, Nature Climate Change 6, 791–795