Forests Feed the Stratosphere Via Monsoons

A haze of fine particles hangs above the weather, and it never clears. A study argues that about 40 percent of it started as gas drifting off leaves.

This is the stratosphere's leftover haze, the stuff still floating in the calm spells between big eruptions and wildfire plumes. It scatters sunlight and gives ozone-related chemistry a surface to happen on. For decades, its makeup and origins stayed uncertain.

The study, published Sept. 25, 2026, in Nature Geoscience, points at forests. Plants give off enormous amounts of reactive gases such as isoprene. Monsoon thunderstorms, among the deepest on the planet, can vacuum air from near the ground to the doorstep of the stratosphere within hours. The same storms rain particles back out, but the gases appear to keep building new particles after they arrive, up where rain can't reach.

Researchers led by Kai Qie and Pengfei Yu of Jinan University paired measurements from nine aircraft campaigns, some reaching about 19 kilometers (12 miles) up, with a climate model. The haze thickened on a seasonal schedule matching monsoon storms over southern Asia, central Africa, South America and the Indonesia-Australia region.

They estimate that 420,000 to 720,000 metric tons of this plant-born material reach the stratosphere each year. That is 5 percent to 90 percent more than volcanoes averaged across the last 20 years, a quiet stretch for eruptions.

Climate models, ozone forecasts and proposals to spray sulfur that high all depend on knowing what is already up there, and a large share of it looks plant-made. Deforestation cuts those leaf emissions, which ties the haze to whatever happens to the forests.

Every monsoon season, the Amazon and the Congo basin send another load up to cruising altitude. No ticket required.

Read the full story at Scienmag, September 25, 2026

Hot Take: Volcanoes have to explode to reach the stratosphere. Trees get there by standing in a thunderstorm and exhaling. Work smarter.