Volcanic ash can scrub planet-warming methane from the sky
A single massive eruption in the Pacific recently triggered a chemical reaction that neutralized as much methane as the daily output of two million cows.
When the Hunga Tonga-Hunga Ha'apai volcano exploded in 2022, it did more than shatter windows thousands of miles away; it turned the sky into a giant air purifier. By lofting salty seawater and mineral ash into the stratosphere, the eruption created a cocktail of iron salt particles. When hit by sunlight, these particles released reactive chlorine atoms that acted like a chemical scissors, snipping apart methane molecules at a rate of 900 megagrams per day. While methane is a potent greenhouse gas with eighty times the warming power of carbon dioxide over twenty years, this volcanic scrub acted as a natural emergency brake.