A massive underwater volcanic eruption in the South Pacific in 2022 may have revealed a new way to reduce methane, one of the most potent greenhouse gases driving global warming, according to a new study.
Researchers studying the eruption of the Hunga Tonga-Hunga Ha'apai volcano found evidence that the blast may have triggered a natural process that helped destroy methane in the atmosphere, according to a study published in the journal Nature Communications on May 7, CNN reported.
The volcano erupted in January 2022 with a force hundreds of times greater than the Hiroshima nuclear explosion, sending ash, steam and gas nearly 40 miles into the sky. The eruption caused a tsunami and a sonic boom that circled the planet twice.
Scientists tracked a large cloud of formaldehyde, a chemical that forms when methane breaks down. The cloud remained visible for 10 days. "We found a huge cloud of formaldehyde that should normally not be there," said Maarten van Herpen, a study author and executive director at Acacia Impact Innovation.
The researchers estimate that the volcano released about 330,000 tonnes of methane. Of that, roughly 900 tonnes were being broken down each day through this natural chemical process.
Scientists had previously discovered that when dust from the Sahara Desert blows across the Atlantic Ocean, it mixes with sea salt in the air, creating tiny iron-rich particles. When sunlight shines on these particles, they produce chlorine atoms, which react with methane and break it down.
Researchers believe a similar process occurred after the Tonga volcano erupted. The blast sent enormous amounts of salty water vapour and volcanic ash high into the atmosphere – enough water to fill about 58,000 Olympic-sized swimming pools.
Methane is one of the most powerful greenhouse gases. Over a 20-year period, it traps about 80 times more heat than carbon dioxide. Scientists estimate that methane is responsible for around one-third of global warming today, and its concentration in the atmosphere has doubled over the past 200 years.
However, some scientists are not fully convinced by the proposed process.
Pete Edwards, who was not involved in the study, said the findings are interesting but difficult to confirm. "The proposed chemistry still needs to be thoroughly tested in atmospheric models," he said.
Scientists also warn that deliberately altering the atmosphere could have unintended consequences.
