Satellites tracked a formaldehyde-rich plume from the 2022 Hunga Tonga-Hunga Ha'apai eruption across earth's atmosphere, and researchers say the cloud kept destroying methane for more than a week. The plume drifted through the stratosphere and reached South America after being visible for 10 days.
Maarten van Herpen, a researcher at Acacia Impact Innovation BV, said, "When we analysed the satellite images, we were surprised to see a cloud with a record-high concentration of formaldehyde." The team estimated that the plume destroyed around 900 metric tons of methane per day, a level they compared with the yearly methane output of two million cows.
Sentinel-5P Tracks The Plume
The researchers used TROPOMI, an instrument aboard the European Space Agency’s Sentinel-5P satellite, to follow the cloud as it moved across the Pacific toward South America. They reported formaldehyde levels as high as 12 parts per billion at about 30 kilometers altitude.
The plume was tied to the 2022 eruption of Hunga Tonga-Hunga Ha'apai, a submarine volcano sitting roughly 150 meters below the ocean surface. Parts of the plume reached more than 30 kilometers above Earth’s surface, where the cloud appeared to act like a high-altitude chemical reactor.
Matthew Johnson On Stratospheric Chemistry
Matthew Johnson, a professor at the University of Copenhagen, said, "What is new, and completely surprising, is that the same mechanism appears to occur in a volcanic plume high up in the stratosphere, where the physical conditions are entirely different," The researchers say the destruction was powered by seawater, ash, salt, and sunlight, with formaldehyde forming as methane broke apart.
Formaldehyde usually survives only a few hours in sunlit air, which is why the 10-day signal stood out to the team. Van Herpen said, "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."
Hunga Tonga-Hunga Ha'apai And Methane
The eruption also injected a massive amount of water vapor into the stratosphere and increased the stratospheric water burden by about 10 percent. That left the plume doing two things at once: carrying an unusual chemical signature and adding water to a part of the atmosphere where such a process is rarely seen.
The finding does not describe a way the volcano removed its own broader climate effect. It does show that satellites can catch short-lived chemistry in motion above the Pacific, and that this plume kept breaking down methane long enough for researchers to measure the process from space.
