SACRAMENTO, Calif. — Megafires and gigafires were terms rarely used to describe the size of blazes across the West. Now, single fires are burning hundreds to millions of acres each year.
In 2020 alone, 8.8 million acres burned. That was five times the average yearly 1.69 million acres burned from 1984 to 2000.
According to a new study out of University of California, Los Angeles, human-induced climate change is the main driver of this increase.
Rong Fu, a lead researcher of the study, says they estimate two-thirds of the intensifying wildfire activity is due to increasing greenhouse gases and only one-third can be explained by changing weather patterns.
Fu says they came to this conclusion by studying the single most important variable in determining the rapid increase in wildfire in the West. It’s called vapor pressure deficit (VPD).
According to Fu, this is a measurement of how thirsty the air is and how much the atmosphere will draw moisture out of plants and soil. A higher VPD tends to draw more moisture from land surfaces leaving fuel prime for burning.
Fu says that higher VPD is usually due to higher temperatures, helping to tie together the connection between a warming climate and increasing wildfire intensity.
She says that because this study shows the main driver of fire frequency and intensity across the West is climate change, the chance of fire danger going down in the future is very slim.