SOUTH PACIFIC OCEAN — A study published on May 7, 2026, in Nature Communications found that the January 2022 eruption of the Hunga Tonga–Hunga Ha’apai volcano triggered chlorine-driven chemical reactions that destroyed methane in the atmosphere for more than a week. The eruption, which launched a plume of ash, gas, and seawater 55 kilometers into the atmosphere, lofted more than 100 million metric tons of salty water and produced an estimated 300,000 to 330,000 tons of methane.

Researchers observed that chlorine-driven reactions in the volcanic plume destroyed approximately 900 tons of methane per day. The presence of formaldehyde—a compound that forms as methane breaks down and typically lasts only a few hours—was detected for several days, indicating ongoing methane destruction. Scientists used data from the European Space Agency’s Tropospheric Monitoring Instrument to track formaldehyde as a proxy for methane loss.

“Because formaldehyde only exists for a few hours, this showed that the cloud must have been destroying methane continuously for more than a week,” said Maarten van Herpen, a physicist with Acacia Impact Innovation in Heesch, Netherlands. He added, “It has emitted methane and then destroyed these emissions through the particles in the plume.”

Matthew Johnson, a chemistry professor at the University of Copenhagen and a study author, called the discovery unexpected. “It’s new — and completely surprising that the same chemical process observed over the Atlantic occurred in the volcanic plume,” Johnson said. He added, “It’s an obvious idea for industry to try to replicate this natural phenomenon — but only if it can be proven to be safe and effective.”

Pete Edwards, an atmospheric chemist at the University of York in England who was not involved in the research, emphasized the risks of introducing chlorine into the upper atmosphere. “I don’t think we should go anywhere near injecting chlorine into the stratosphere. We’ve done that before, and it didn’t go well,” Edwards said. He added, “Chlorine in the stratosphere is a bad thing,” noting that it reacts with ozone about 380 times faster than with methane in cold stratospheric conditions.

The study’s observations occurred in the stratosphere, while proposed methane removal techniques involving iron-based particles would operate in the lower atmosphere. Methane, which persists for about a decade and is roughly 80 times more potent than carbon dioxide at trapping heat over 20 years, accounts for about one-third of current global warming.