Climate Number: 2,930,000,000,000 Pounds
Globally, wildfires affect an average of 1.4 million square miles of land each year. Fire has been an important factor in terrestrial ecosystem development and dynamics for at least 400 million years. Savanna ecosystems, found mostly in Africa between the tropical rainforest and desert ecosystems, burn the most, contributing 47.8 percent of the global dry biomass (wood, grasses, leaves, etc.) that is consumed by wildfire. Forest fires, like those experienced in North America, account for 23.5 percent of the dry biomass consumed. Shrublands, croplands and grasslands each account for about 10 percent of the remainder. In total, about 2.93 x 1012 pounds of dry biomass burn across Earth’s ecosystems each year, releasing about two gigatons of carbon into the atmosphere, which is about 22 percent of the emissions from fossil fuel burning. Apart from their obvious impacts on the landscape and the dangers they pose to humans, wildfires also significantly affect local and regional air quality. In North America, the primary emission season occurs between May and September. In the agricultural regions of central North America, peak emissions occur during the fertilizing season of April and May, whereas in the western United States, peak emissions occur in July and August. For human health, one of the most important components of these emissions are fine particulates, tiny particles about 1/30th the diameter of a human hair which can damage lungs and respiratory function. The maximum monthly emissions of fine particulates for the peak month of July in North America is 7.39 x 108 pounds. The timing and magnitude of the peak emission season may be changing – since the mid-1980s, the length of the western United States wildfire season has grown 78 days longer as a result of earlier snowmelt and increased spring and summer temperatures.
For comparison: 2.93 x 1012 pounds is four times the weight of all the corn grown in the United States each year. Corn is America’s biggest crop.
Source: Zhang, X et al. “Near-real-time global biomass burning emissions product from geostationary satellite constellation.” Journal of Geophysical Research 117 (2012): D14201.