Researchers have found that Australian bus fires that invaded the country were so large that they erupted as much smoke into the stratosphere as a massive volcanic eruption, with a detrimental effect on the environment, according to a study published Thursday in the journal Science.
The stratosphere is the second layer of the atmosphere, just above the troposphere, where we live.
Co-author of the study Ilan Koren, who is a professor at the Weizmann Institute of Science in Israel, said, “For us, it was a big surprise.”
“I’ve never seen such an injection (of smoke) into the stratosphere,” he said.
The amount of smoke released into the atmosphere by the fires is comparable to the eruption erupted by the Mount Pinatubo eruption in the Philippines in 1991, making it the second largest city. in the 20th century.
Researchers noted that the fog moved away from Australia to the east, and returned from the west two weeks later.
“We could see the fog finish a full cycle in two weeks,” Koren said. “I’ve never seen such a strong event unfold so quickly.”
The phenomenon can be explained by three factors, according to the study.
At first, the fires themselves were intense. Second, they occurred in an area of southern Australia where the distance between the troposphere and the stratosphere is less than elsewhere. And finally, the fires occurred near strong storms, which helped to pull the smoke up higher into the atmosphere.
The fact that the mist was able to grind so high to understand its environmental impact: Normally, that mist may only remain in the lower part of the atmosphere for a few days or weeks.
“But once it reaches the stratosphere, it stays between months to a year,” Koren explained.
The winds are stronger up there, allowing the smoke to disperse farther and faster than would otherwise be possible.
“Basically what we’re getting is a thin blanket of mist that will cover the entire hemisphere for several months,” Koren said.
‘Not clear yet’
Researchers will see the fog in the stratosphere for six months, from January to July 2020, through a satellite survey.
Eventually, it became too difficult to separate the smoke from Australian bush fires from smoke in the stratosphere that may have come from other sources.
“But it seems that there is still a signature of the smoke in the stratosphere today,” Koren said.
The main effect of the smoke is to stay in the atmosphere as long as it can expose radiation coming from the sun.
According to Koren, that “definitely has an overall cooling effect,” especially on the ocean, disrupting processes such as photo-algae synthesis in the southern hemisphere.
The fog can also absorb solar radiation, which can provide a local warming effect.
“The results from the warming of the fog in the stratosphere are not yet clear,” Koren said.