Wildfires & Carbon In Our Atmosphere
The Big Q: Do wildfires have a significant impact on global warming?
The Big A: Much depends on what the fire destroys, there is tremendous variation among the species of trees in terms of carbon storage.
Overall, the most carbon dense trees are those with high-density wood and large trunk diameters.
So, when a wildfire sweeps through a forest of mighty evergreens, the carbon emissions will be much higher than if the conflagration was consuming less dense trees.
In the United States, the carbon-rich forests run from Northern California up and through the State of Washington.
Also, a factor is the composition of the soil.
The fires that swept across Indonesia in Y 1997, for example, burned relatively thin-trunked tropical trees. But the devastated forests were also covered in carbon-rich peat, with deposits measuring up to 20 mtrs deep.
So, as a result, the Indonesian fires were estimated to have released between 0.81 and 2.57 gigatons of carbon or between 13 and 40% of the world’s annual emissions at the time.
The typical wildfire in North American is not that devastating in terms of carbon emissions.
Environment Canada estimates that for every acre of primarily coniferous forest burned, approximately 4.81 tonnes of carbon is released into the atmosphere—between 80 and 90% in the form of carbon dioxide (CO2), with the rest as carbon monoxide (CO) and methane (CH4).
In Y 2006, a record-setting 96,385 wildfires destroyed about 9.87-M acres of forest in the United States.
In Y 2015 forest fires accounted for 47.47-M tonnes of carbon emissions in the United States.
In comparison, the nation’s annual carbon dioxide emissions are said to be around 6.049-B tonnes.
This estimate does not take into account the carbon released by vegetation that decays once the fires have been extinguished.
Also, it does not it include the long-term effects of losing forests, which absorb carbon dioxide from the atmosphere converting it to oxygen helping to slow global warming.
That data indicates that global warming seems to increase the frequency of wildfires.
According to a recent University of Arizona study, the length of the wildfire season has increased by roughly 3 months since the mid-1980s, mostly due to earlier snow melts in the West.
A earlier melt means that dried, easily ignited brush spends more time lying on the ground.
A Y 2004 Kansas State University study included a prediction that carbon dioxide emitted by American wildfires will 2X by Y 2100.
But, you have to know and understand that wildfires also play a vital role in replenishing a forest’s soil and clearing away dead and rotten trees.
Wildfires are typically sparked by lightning, and humans.
In Y 2006 naturally occurring fires were responsible for more than 50% of the 9.87-M acres of forest burned in the United States. The rest were started by people.
Note: prior to the 1800’s, Native Americans are estimated to have burned roughly 4.5-M acres of land per year to manage game, spur the growth of edible plants, and deprive enemies of cover.
So, while we should be concerned about the growing frequency of wildfires and their attendant effects on global warming, we should understand that in nature it is part of the process of life and growth.
But, when it comes to humans starting fires on purpose or by carelessness we have to become alert and do our best to protect against their destruction of lives and property.
Have a terrific week.