This volcano didn’t just erupt—it triggered a hidden atmospheric cleanup scientists never expected to see

When the submarine volcano Hunga Tonga–Hunga Ha’apai within the South Pacific erupted in January 2022, it was not solely one of the crucial violent volcanic eruptions in fashionable occasions. The volcano additionally did one thing fully sudden: it helped clear up a number of the methane air pollution it launched. This phenomenon may doubtlessly be key to how people can sluggish international warming.

Using superior satellite tv for pc measurements, researchers noticed unusually excessive concentrations of formaldehyde within the huge volcanic plume following the eruption. This was essential proof: when methane is destroyed within the environment, formaldehyde types as a short-lived intermediate.

“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,” explains Dr. Maarten van Herpen from Acacia Impact Innovation BV.

“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,” he provides.

The study has been printed in Nature Communications.

Salt, daylight and new chemistry

According to the researchers, every little thing factors to a very particular course of happening—one they first found in 2023, however in a fully completely different a part of the world.

They discovered that when mud from the Sahara is blown over the Atlantic Ocean, it mixes with sea salt from sea spray, forming small particles often known as iron salt aerosols. When daylight hits these aerosols, chlorine atoms are produced. These chlorine atoms react with methane and assist break it down within the environment. This discovery modified scientific understanding of tropospheric chemistry.

“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,” says Professor Matthew Johnson from the Department of Chemistry on the University of Copenhagen, one of many researchers behind each discoveries.

The 2022 eruption harm monumental quantities of salty seawater into the stratosphere together with volcanic ash. The idea is that when daylight hit this combination, extremely reactive chlorine was fashioned, serving to to break down the methane launched in the course of the eruption. The seen proof of this methane breakdown was the big quantities of formaldehyde detected in satellite tv for pc photos.

Methane is at the moment accountable for one third of world warming. Over a 20-year interval, methane is about 80 occasions as potent as CO₂. However, methane breaks down comparatively rapidly within the environment—sometimes inside about 10 years.

This implies that if we scale back methane emissions now, it may have a noticeable influence on the local weather inside a decade. For this purpose, researchers generally refer to methane reduction as an “emergency brake” on local weather change—one which will assist forestall local weather tipping factors within the coming a long time. However, decreasing CO₂ emissions stays important to stabilize temperatures in the long run.

Inspiration for future options

The researchers behind the brand new examine imagine their findings may inform a rising discipline engaged on options to scale back methane emissions by artificially accelerating its breakdown within the environment—related to how the volcano successfully cleaned up after itself. Various strategies are at the moment underneath investigation, however a key problem is measuring and verifying how a lot methane is definitely eliminated.

“How do you prove that methane has been removed from the atmosphere? How do you know your method works? It’s very difficult. But here we address that problem by showing that methane breakdown can in fact be observed using satellites,” says Dr. Jos de Laat from the Royal Netherlands Meteorological Institute, senior creator of the examine.

The analysis was carried out with the superior TROPOMI instrument aboard the European Space Agency’s Sentinel-5P satellite tv for pc, which displays air air pollution and greenhouse gases worldwide on a day by day foundation.

“Retrieving formaldehyde from TROPOMI in a stratospheric volcanic plume is far outside the instrument’s standard operating conditions—we had to carefully correct the satellite’s sensitivity for the unusual altitude of the signal and account for interference from the high sulfur dioxide concentrations. Getting these corrections right was essential to confirm that what we were seeing was real,” stated Dr. Isabelle De Smedt, Royal Belgian Institute for Space Aeronomy.

The researchers imagine the brand new findings will encourage engineers in trade:

“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. Our satellite method could offer a way to help figure out how humans might slow global warming,” Johnson concludes.

“We now know that atmospheric dust—for example from a volcanic eruption—impacts the methane budget, meaning the budget of how much methane is added to the atmosphere and how much is removed. Because dust has not previously been taken into account, it is important that we correct the data on which these estimates are based,” says Johnson.