Washington- The number of days when the weather is hot, dry and windy – ideal for triggering forest fires extremes – has almost tripled in the last 45 years worldwide, and the trend is even greater in the American continent, a new study shows.
Researchers estimated that more than half of that increase is due to human-caused climate change.
This means that, As the world warms, more places on the planet are likely to burn at the same time due to increasing fire synchronization, which occurs when multiple places meet the right conditions to burn. According to the authors of a study published Wednesday in Science Advances, countries may not have enough resources to put out all the fires that arise and help may not come from neighbors busy with their own flames.
According to the study, in 1979 and for the following 15 years, the world recorded an average of 22 synchronized fire days per year for flames that remained within large global regions. In 2023 and 2024, the average will exceed 60 days per year.
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“These types of changes increase the probability of hard-to-extinguish fires in many areas,” says John Abatzoglou, co-author of the study and fire scientist at the University of Californiain Merced.
The researchers did not look at the actual fires, but at the weather conditions: hot, with strong winds and dry air and soil.
“It increases the likelihood of widespread fires, but climate is one dimension,” said the study’s lead author, Cong Yin, a fire researcher at the University of California, Merced. The other major ingredients of fires are oxygen, fuel, such as trees and brush, and ignition, such as lightning, arson, or human accidents.
This study is important because extreme weather conditions are the main factor – although not the only one – in the increase in the impact of fires around the world, according to scientist Mike Flannigan of Thompson Rivers University in Canada, who was not involved in the study. And it’s also important because regions that used to have different fire seasons and could share resources now overlap, he said.
said Abatzoglou: “And that’s where things start to break down.”
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According to Yin, more than 60% of the global increase in synchronized fire days can be attributed to climate change caused by the combustion of coal, oil and natural gas. He and his colleagues know this because they used computer simulations to compare what happened over the past 45 years with a fictional world without the increase in greenhouse gases from burning fossil fuels.
Between 1979 and 1988, the continental United States recorded an average of 7.7 synchronized fire days per year. But in the last 10 years that average rose to 38 days a yearaccording to Yin.
But that’s nothing compared to the southern half of South America. That region recorded an average of 5.5 days of synchronized fires per year between 1979 and 1988; Over the past decade, that figure has increased to 70.6 days a year, including 118 days in 2023.
Of the world’s 14 regions, only Southeast Asia saw a decline in synchronized fires, probably because the humidity there is increasing, Yin explained.