Every time there is a forest fire (ie wildfire) global warming alarmists, like a pack of Pavlov's dogs, start hysterically howling that human CO2 caused the recent incendiary event...while at the same time claiming their predictions of increasing wildfire damage from CO2-warming are coming true...however, like always, the empirical evidence proves the alarmists are without scientific portfolio.....
Let's cut to the chase - are human CO2 emissions causing an increase in U.S. forest acreage being decimated by flames?
The adjacent chart is a plot of U.S. wildfire acreage going back to 1926, through the end of 2013. The green curve represents acres burnt (in millions).
In addition, the chart includes the plot of lumber harvested (billion board-feet) from U.S. forests and atmospheric CO2 levels over the same approximate time span. The brown curve is the lumber harvest; the grey curve is CO2 (ppm).
What does the chart indicate?
Wildfire acreage burnt collapsed after the 1930s. Not only did this collapse coincide with a growth of atmospheric CO2 levels from human CO2 emissions, the huge decrease in acres burnt took place when the harvesting of lumber from U.S. forests grew massively.
Then, as the total amount of harvested lumber declined and reached a significantly lower level - due to new environmental regulations - the number of acres burnt each year started to incrementally increase during the 1990's.
Intuitively this makes sense. As the dead and disease-infected trees started to pile up from lack of harvesting due to environmentalist concerns and government regulations, the U.S. forests became wildfire tinderboxes, easily set off by lightening and human carelessness - the law of unintended consequences from passionate 'green' policies strikes again.
Per the statistical relationships, both board-feet harvested and CO2 levels have an inverse correlation (-0.6 and -0.5, respectively) with the acreage scorched, across the entire time span.
Conclusion: It's always dangerous to draw firm conclusions from just statistics, but the empirical evidence strongly suggests that both lumbering and higher CO2 levels makes for less wildfires. The record clearly shows that wildfire damage over the last two decades are not unprecedented, and it remains well below the horrendous amount of acres burned during the early 20th century. For policymakers, the sanest recommendation towards improving U.S. forest health is to increase the amount of allowed lumbering, thus thinning forests of tinderbox materials; plus, to recognize any future CO2 increases as a potential contributor to healthy forest growth.
Note: The wildfire acreage burned during years 1926-1959 and the lumber board-feet harvested came from this congressional testimony by scientific forestry expert; post 1959 data from this government agency site. CO2 datasets found here. The chart's right axis represents both atmospheric CO2 levels and harevested board-feet. For the latter, the largest number at the top, '1300', reads as 13 billion board-feet; for CO2, it would read 1,300 ppm.