Washington– The number of days it is there The weather is getting hotDry and windy – perfect for excitement Severe forest fires – It has nearly tripled over the past 45 years worldwide, with the trend increasing even further in the Americas, a new study shows.
More than half of this increase is due to: Human-caused climate change Eh, according to the researchers.
What this means is that as the world warms, more places around the world are vulnerable to catching fire at the same time due to increasingly synchronized fire weather, which is when multiple places have the right conditions for smoke to ignite. Countries may not have enough resources to put out all the fires that appear, and help is unlikely to come from neighbors busy setting their own, according to the authors of a study published in the journal Science Advances on Wednesday.
The study found that in 1979 and over the next 15 years, the world averaged 22 days of synchronous fire weather days per year for fires that remained within large global areas. In 2023 and 2024, the number reached more than 60 days a year.
“These kinds of changes we’ve seen increase the likelihood of fires in a lot of areas that will be very difficult to put out,” said study co-author John Apatzoglou, a fire scientist at the University of California, Merced.
The researchers did not look at actual fires, but rather at weather conditions: warm, with strong winds and… Dry air and ground.
“It increases the likelihood of large-scale fires, but weather is one dimension,” said study lead author Kong Yin, a fire researcher at the University of California, Merced. Other large components of fires are oxygen, fuels such as trees and branches, and ignition such as lightning, arson, or human accidents.
Fire scientist Mike Flanigan of Thompson Rivers University in Canada, who was not part of the study, said the study is important because extreme fire weather is the primary — but not the only — factor in increasing fire impacts around the world. It’s also important because areas that used to have fire seasons at different times and can share resources are now overlapping, he said.
“And this is where things start to fall apart,” Apatzoglou said.
More than 60% of the global increase in synchronous fire weather days can be attributed to climate change caused by burning coal, oil and natural gas, Yin said. He and his colleagues know this because they used computer simulations to compare what happened in the past 45 years to an imaginary world free of rising greenhouse gases from burning fossil fuels.
The average number of days of concurrent fire weather in the continental United States, from 1979 to 1988, was 7.7 days per year. But in the past 10 years, that average has reached 38 days a year, according to Yin.
But this is nothing compared to the southern half of South America. The number of days of simultaneous fire weather in that region averaged 5.5 days per year from 1979 to 1988; Over the past decade, that has risen to 70.6 days per year, including 118 days in 2023.
Of the 14 global regions, only Southeast Asia saw a decrease in synchronized fire weather, possibly due to increased humidity there, Yin said.
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