Researchers analyzing the 2022 eruption of the Hunga Tonga-Hunga Ha’apai submarine volcano discovered that its plume actively destroyed methane in the atmosphere. By detecting high levels of formaldehyde via satellite, scientists found that volcanic ash combined with salt and sunlight created reactive chlorine particles that neutralized the potent greenhouse gas.
The January 15, 2022, eruption of the Hunga Tonga-Hunga Ha’apai volcano in the South Pacific is recognized as one of the most powerful volcanic events in modern history. While such eruptions typically contribute to atmospheric pollution by releasing gases, new analysis reveals that this specific event triggered a chemical reaction that partially cleaned the air of methane, a primary driver of the greenhouse effect.
Formaldehyde as a Chemical Fingerprint
The discovery relied on the detection of formaldehyde within the massive plume of ash and gas. In atmospheric chemistry, formaldehyde serves as a short-lived intermediate; it is produced specifically when methane breaks down. Because formaldehyde exists for only a few hours, its presence in high concentrations over a long period indicates a continuous process of methane destruction.
Using the TROPOMI and VIIRS satellites, researchers identified a cloud with a record-high concentration of formaldehyde. The persistence of this cloud provided the critical evidence for the study. Scientists tracked the formaldehyde plume for 10 days as it traveled across the ocean toward South America.
When we analyzed the satellite images, we were surprised to see a cloud with a record-high concentration of formaldehyde. We were able to track the cloud for 10 days, all the way to South America. Because formaldehyde only exists for a few hours, this showed that the cloud must have been destroying methane continuously for more than a week.
Dr. Maarten van Herpen, Acacia Impact Innovation BV
The Role of Salt and Reactive Chlorine
The mechanism driving this methane removal is a result of the volcano’s unique submarine environment. The eruption blasted volcanic ash and salty seawater high into the atmosphere. When exposed to sunlight, this mixture of ash and salt created reactive chlorine particles.
These chlorine particles acted as a catalyst, attacking methane molecules and breaking them down. This process effectively neutralized a portion of the methane released by the eruption itself, as well as methane already present in the surrounding atmosphere. While it is established that volcanoes emit methane during eruptions, this study marks the first time researchers have observed volcanic ash acting as a cleaning agent for this specific pollutant.
It is known that volcanoes emit methane during eruptions, but until now it was not known that volcanic ash is also capable of partially cleaning up this pollution.
Dr. Maarten van Herpen, Acacia Impact Innovation BV
This specific chemical process was not entirely new to the researchers; they first identified a similar reaction in 2023 in a different region of the world. However, the scale of the Hunga Tonga-Hunga Ha’apai eruption allowed for a detailed observation of the process in a massive, high-altitude plume.
Implications for Climate Mitigation
The findings, published in Nature Communications
, suggest that the interaction between salt, sunlight, and mineral particles can be used to destroy potent greenhouse gases. Methane is significantly more effective at trapping heat than carbon dioxide, making its removal a high-priority target for slowing global warming.
The observation that a natural event could trigger such a large-scale atmospheric cleanup may inform future strategies for human-led atmospheric intervention. By understanding the precise conditions under which reactive chlorine destroys methane, scientists may develop new technologies to replicate this effect without the destructive force of a volcanic eruption.
Atmospheric Dynamics of the 2022 Event
The 2022 eruption was characterized by its extreme violence, punching a plume through the atmosphere and into the mesosphere. This altitude allowed the resulting chemical reactions to occur across a vast area, influencing atmospheric chemistry far beyond the immediate vicinity of the South Pacific.
The research conducted by Dr. van Herpen and his team at Acacia Impact Innovation BV highlights a complex duality in volcanic activity. While the eruption caused immediate geological and environmental disruption, it simultaneously revealed a natural mechanism for reducing atmospheric methane. The ability of the plume to maintain methane-destroying properties for over a week suggests that the reactive chlorine particles remained stable and active throughout their journey to South America.
As researchers continue to analyze the long-term data from the Hunga Tonga-Hunga Ha’apai event, the focus remains on whether these findings can be scaled into viable atmospheric clean-up efforts. The current evidence confirms that the atmosphere possesses hidden chemical pathways that can be triggered by specific mineral and saline conditions to mitigate the presence of greenhouse gases.