Over the past two decades, the amount of land in the western United States that has been damaged by big wildfires has increased significantly as a result of climate change, according to new research from UCLA and Lawrence Livermore National Laboratory. According to the study’s co-author and UCLA professor of atmospheric and marine sciences, Rong Fu, this pattern will only increase in the coming years. If climate change is to blame for the recent record-setting fire seasons in the American West, I fear that our civilization will not be able to cope with a rapidly rising number of wildfires in the region.
Statistics from the U.S. Geological Survey show that wildfires are wreaking more havoc than they ever have. A total of 1.69 million acres of land burnt annually in 11 western states between 1984 and 2000. A total of 3.35 million acres were burned annually for the next 17 years, from 2001 to 2018. Wildfires scorched 8.8 million acres in the West in 2020, according to a data from the National Interagency Coordination Center. This area is larger than the state of Maryland. Human-induced climate change and natural temperature variance, forest management, earlier springtime snowmelt, and lower summer rain have all been cited as possible causes of the significant increase in the number of wildfires in the United States. An artificial intelligence-based approach was used to analyze climate and fire data in order to determine the impact that climate change, as well as other factors, play in determining the most important climate variable linked to wildfire risk, which is vapor pressure deficit (VPD).
To calculate the vapor pressure deficit, you must subtract the amount of moisture in the air from the amount the air can hold when it is saturated. An increase in vapor pressure deficit, or VPD, allows for more moisture absorption by air. Vapor pressure deficits, which are linked with warm, dry air, are common in large wildfire-burned areas that are not located close to population centers. According to the findings, human-caused global warming was responsible for an increase in western U.S. vapor pressure deficit of 68% between 1979 and 2020. The authors determined that the remaining 32 percent difference was likely due to natural weather trends. This suggests that human-induced climate change is the primary driver of increased fire conditions in the western United States.
Director of UCLA’s Joint Institute for Regional Earth System Science and Engineering, a partnership with NASA’s Jet Propulsion Laboratory, claimed that “our estimates of the human-induced influence on the increase in fire weather risk are likely to be cautious.” More than a million acres of Northern California were destroyed by the so-called August Complex wildfire of 2020, which academics studied. According to their findings, human-induced warming is likely responsible for at least 50 percent of the region’s unusually high VPD during the month the fire started. Fu believes that, despite recent rain and cooler temperatures, wildfires will continue to grow in intensity and frequency in the western states. The vapor pressure deficit would likely not worsen wildfires in locations where great tracts of plant life have already been destroyed by fire, drought, heatwaves, and road construction.
When it comes to vapor pressure deficit, “human-induced warming is now more responsible than natural atmospheric circulation changes in the western United States,” Fu said in an interview. This shift has occurred significantly sooner than expected, according to our research, which dates back to the dawn of the twenty-first century. UCLA postdoctoral scholar Yizhou Zhuang is the paper’s lead author, along with UCLA professor of atmospheric and oceanic sciences Alex Hall, UCLA Center for Climate Science Director Benjamin Santer, and UCLA distinguished professor in residence of atmospheric and oceanic sciences Robert Dickinson. They all worked on the paper together.