When a volcano erupts it sends thousands of tons of gases into the atmosphere – all of which can weaken the ozone layer. A team of German meteorologists studying giant eruptions in Nicaragua recently reported that due to the amount of ozone-depleting halogen gases already in the stratosphere (through man-made actions), if the world suffered a substantial eruption it could devastate the ozone layer.
Kirstin Krueger, a meteorologist with GEOMAR in Kiel, Germany noted that bromine and chlorine (two gases that are frequently erupted) “love to react — especially with ozone. If they reach the upper levels of the atmosphere, they have a high potential of depleting the ozone layer.” The team conducted field work and a series of geochemistry and existing atmospheric models to study previous Nicaraguan eruptions and found that they were explosive enough to reach the stratosphere and have an effect on the protective ozone layer.
Team member Steffen Kutterolf, a chemical volcanologist with GEOMAR, studied the gases that were released and used high-energy radiation from the German Electron Synchrotron in Hamburg to detect trace elements, including bromine. By studying the amount of gas within magma before the eruptions, he was able to calculate how much bromine and chlorine are released in a typical eruption.
The facts are unsettling: the typical eruption sends mushroom clouds of ash kilometers high, with 25% of halogens making it into the stratosphere. However the team only estimated 10% of the gases reaching the ozone layer for their study. Even worse, the gases that do reach the stratosphere can be carried across the globe leading to ozone depletion over a large area.
Krueger and her team are currently presenting their findings at the American Geophysical Union’s Chapman Conference on Volcanism and the Atmosphere in Selfoss, Iceland where they hope to predict future ozone destruction from the lessons of the past.