The 2022 eruption of the undersea volcano Hunga Tonga–Hunga Ha’apai in the South Pacific not only released significant amounts of methane but also triggered a chemical reaction that significantly reduced atmospheric levels of the greenhouse gas, according to new research. The initial explosion launched approximately 360 kilotons of methane into the atmosphere, a potent contributor to global warming, but also generated conditions that led to the destruction of about 990 tons of methane daily for over a week.

Scientists studying the event found that saltwater propelled into the stratosphere by the volcanic blast interacted with volcanic ash and sunlight, producing highly reactive chlorine compounds. These chlorine compounds in turn broke down methane molecules. Satellite imagery of the volcanic plume revealed elevated levels of formaldehyde, a short-lived compound formed when methane is oxidized, providing direct evidence of this chemical process.

Methane is a powerful greenhouse gas with roughly 80 times the warming potential of carbon dioxide over a 20-year period, making its removal from the atmosphere a critical target for climate mitigation efforts. The study’s findings suggest that the natural chemical mechanisms triggered by the eruption could potentially be harnessed or replicated to reduce methane concentrations more broadly.

Matthew Johnson, a co-author of the study and researcher at the University of Copenhagen, emphasized that exploring the possibility of using chlorine chemistry to scrub atmospheric methane warrants further investigation. He noted that while the volcanic reaction offers a promising insight, any efforts to mimic this process would require thorough assessment to ensure safety and effectiveness.

The discovery offers a novel perspective on the complex interactions between volcanic activity and atmospheric chemistry and opens new avenues for research into mitigating methane-driven climate change. However, the feasibility and environmental implications of artificially inducing such chemical reactions remain to be fully evaluated.