| 29 May 2024, Wednesday |

Study finds that humans, climate change are largely responsible for fires in US west

A study published Monday, showed that the forest fires regularly destroying the Western United States are the result of climate change caused largely by human activity.
From 2001 to 2018, fires destroyed an average of 13,500 square kilometres (5,200 square miles) per year in the American west, double what they destroyed between 1984 and 2000.
“It’s happened so much faster than we previously anticipated,” Rong Fu, who led the study published by the US National Academy of Sciences (PNAS), told the Los Angeles Times.
As a result of such a significant deterioration of weather conditions in such a short time, a team of American researchers led by Fu analyzed the “vapor pressure deficit” (VPD), which measures how dry the air is.
As an indicator of water in the atmosphere, the VPD represents the difference between the amount that is actually present in the atmosphere and the maximum amount that could exist in the atmosphere. As deficits grow, soil and plants lose more water, drying out and creating conditions that fuel fires.
According to scientists, wildfires in the western United States are correlated with this deficit during the warm season. The study found that the number of high VPD days between May and September increased 94 per cent between 2001 and 2008 compared to the preceding period.
Fu and her colleagues calculated that “natural” atmospheric variations were responsible for only a 32 per cent increase in VPD. Global warming, which is largely the result of human activities, is responsible for the remaining 68 per cent of the increase in atmospheric water deficit.
“Prior to 2000, we can explain this fire weather pretty well just using weather patterns,” said Fu, a climatologist at the University of California UCLA. “But now we can only explain 30 percent of what we see with fire weather.”
The study found that up to 88 per cent of anomalies in the VPD could be explained by anthropogenic or human origin warming.
According to the study, in August 2020, when California experienced the largest fire ever recorded in the region, the August Complex Fire, which burned nearly 4,200 square kilometres (1,600 square miles), anthropogenic warming was responsible for about half of the “unprecedented high” moisture deficit.
Climate experts claim that the planet has already warmed about 1.1 degrees Celsius since pre-industrial times due to greenhouse gases generated by humans. The warming that has been caused primarily by burning fossil fuels has occurred largely in the last 50 years.