Wildfires do more than just destroy forests. Some fires are so powerful they create their own weather, including unusual thunderstorms called pyrocumulonimbus. These can lift smoke high into the atmosphere, where it lingers for weeks or even months. Understanding how this smoke affects our climate has always been tricky, but a new study is changing that.
Researchers from Harvard have made a breakthrough. They conducted the first direct measurements of wildfire smoke five days after a fire in New Mexico in June 2022. Using a high-altitude NASA ER-2 aircraft, they flew right into a smoke plume to analyze its particles.
Inside the smoke, they found aerosols nearly 500 nanometers wide. These larger particles differ from the usual smaller wildfire aerosols found closer to the ground. According to lead researcher Yaowei Li, the size increase is likely due to a process called coagulation. When wildfire smoke particles combine, they can grow larger—especially in areas with slow air movement. This allows for more collisions between particles, leading to more coagulation.
These larger aerosols significantly impact how radiation interacts with the Earth. They can either absorb sunlight or reflect it back into space. The study found these high-altitude particles enhance outgoing radiation by 30% to 36% compared to smaller particles. This could cause a cooling effect that current climate models haven’t considered.
John Dykema, another co-author of the study, notes that these large particles might influence atmospheric patterns, potentially shifting jet streams. “We have yet to explore how these changes could impact weather and climate,” he said. “There’s a lot more to uncover.”
In 2022, wildfires burned more than 7 million acres in the U.S., making intense research like this crucial. According to a report from the National Interagency Fire Center, the trend in wildfire intensity and frequency is rising, indicating that understanding their broader effects on our climate is more vital than ever.
This research was published in the journal Science Advances on December 10. As wildfires continue to threaten ecosystems and air quality, studies like this provide promising insights into their wider implications for our planet.
