Study: underwater volcano a massive chemistry experiment

Science News reported on May 27 that the January 2022 eruption of Hunga Tonga–Hunga Ha’apai has become a natural test case for scientists studying how greenhouse gases behave in the atmosphere. The submarine volcano in the South Pacific blasted ash, gas and seawater about 55 kilometers into the sky, creating a plume large enough for satellites to track its chemistry in detail. (sciencenews.org) Researchers later found evidence that reactions inside that cloud may have broken down some of the methane released during the eruption. The work, published May 7 in Nature Communications, is now being cited as a way to test methods for measuring methane removal from space. ### Why are scientists calling one eruption a chemistry experiment? The January 2022 Hunga Tonga–Hunga Ha’apai blast mixed volcanic ash, seawater and sunlight in a single plume, giving researchers an unusual real-world setting to observe atmospheric reactions. Science News described that plume as a “massive chemistry experiment” because it let scientists watch how reactive chemicals formed and changed after the eruption. Maarten van Herpen of Acacia Impact Innovation told Science News that the event offered a rare chance to test whether methane destruction could be quantified from space. He said the same measurement approach could, in principle, be used to evaluate a future intervention aimed at removing methane from the atmosphere. (sciencenews.org) ### What did the satellites actually detect in the plume? The May 7 Nature Communications paper reported satellite evidence of enhanced methane oxidation in the stratospheric plume after the eruption. According to the University of Copenhagen’s summary of the study, researchers detected large amounts of formaldehyde, which they used as a sign that methane was being destroyed. (sciencenews.org) Maarten van Herpen said in the university release that formaldehyde exists only briefly in the atmosphere, so its presence indicated that methane destruction had continued for more than a week inside the cloud. The authors linked that process to chlorine-mediated chemistry triggered when volcanic material and saltwater interacted in sunlight. (sciencenews.org) ### Where did the chlorine come from? Science News reported that van Herpen and colleagues had previously suggested chlorine atoms can form when iron-rich dust mixes with salt-rich sea spray and sunlight drives the reaction. The Hunga Tonga plume appeared to create a similar setup, but with volcanic ash and seawater replacing desert dust and marine spray. (nature.com) The Nature Communications study said those chlorine atoms are highly reactive and can strip methane apart. The paper’s title and summary describe the process as enhanced methane oxidation in the stratospheric plume following the eruption. (science.ku.dk) ### Why does methane matter more here than carbon dioxide? Science News said methane is responsible for roughly one-third of present-day global warming. The outlet also noted that methane remains in the atmosphere for about a decade, much less than carbon dioxide, which can persist for centuries. That shorter lifetime is one reason researchers have examined methane-removal proposals. (sciencenews.org) Science News reported that van Herpen said a reliable way to measure whether methane is actually being removed is a prerequisite for any such strategy, and the volcanic plume gave the team a real event against which to test those measurements. (nature.com) ### What comes next from this work? Nature Communications published the paper, “Satellite quantification of enhanced methane oxidation applied to the stratospheric plume following Hunga Tonga-Hunga Ha’apai eruption,” on May 7, 2026. The listed authors are Maarten M.J.W. van Herpen, Isabelle De Smedt, Daphne Meidan, Alfonso Saiz-Lopez, Matthew S. (sciencenews.org) Johnson, Thomas Röckmann and Jos de Laat. Science News said researchers want to use the volcano case to judge whether satellite tools can detect methane removal in future experiments. Any next step would depend on the same kind of atmospheric measurements van Herpen said were visible in the Hunga Tonga plume. (nature.com) (sciencenews.org)