Wildfire smoke lofted miles high could have an unexpected effect on Earths climate

Wildfires don’t just scorch landscapes. Some are so intense that they create their own weather systems, such as pyrocumulonimbus thunderstorms that loft smoke up to 10 miles (16 kilometers) into the atmosphere. While it’s long been known that this high-altitude smoke can persist in the atmosphere for weeks or months, their effect on climate has been hard to measure, due to the difficulties in collecting samples. That is, until now.

Atmospheric scientists at the Harvard John A. Paulson School of Engineering and Applied Sciences report the first direct measurements of five-day-old wildfire smoke in the upper troposphere, about nine miles (14.5 kilometers) above Earth’s surface. They discovered large smoke particles that aren’t represented in current climate models, and these particles appear to actually cool the atmosphere.