From 1984 to 2000 the average burned area in 11 western states was 1.69 million acres per year. For the next 17 years, through 2018, approximately 3.35 million acres burned annually. And in 2020, the amount reached 8.8 million acres, an area larger than the state of Maryland. Vapor pressure deficit measures the amount of moisture the air can hold when it’s saturated minus the amount of moisture in the air. When vapor pressure deficit (VPD) is higher, the air can draw more moisture from soil and plants. Large wildfire-burned areas, especially not located near urban areas, tend to have high vapor pressure deficits, conditions associated with warm, dry air. 68% or more of the increase in vapor pressure deficit across the western U.S. between 1979 and 2020 was likely due to human-caused global warming. Wildfires are expected to continue to become more intense and more frequent in the western states overall.
Story Source: University of California Los Angeles
www.sciencedaily.com/releases/2021/11/211105114305.htm