How volcanic eruptions impact the ozone layer
When the Hunga volcano erupted in Tonga in January 2022, its impact was felt both here on Earth and well above it too. With materials reaching an unheard of 30 miles above the Earth’s surface, the eruption changed the chemistry and dynamics of the stratosphere and caused a 7 % loss in the ozone layer over a large swath of the Southern Hemisphere. “While we know that volcanic eruptions can influence the stratospheric ozone, we don’t know exactly how such changes impact the climate and the Earth system in general,” explains Freja Chabert Østerstrøm, an atmospheric scientist at Aarhus University. Helping to answer these questions is the EU-funded SOLVE project.
It’s all about a volcanic eruption’s latitude, season and halogen content
To start, Østerstrøm spent two years at Harvard University conducting 3D chemistry-climate modelling of volcanoes. Part of this work focused on investigating the stratospheric ozone’s sensitivity to an eruption’s latitude, season and halogen content. Halogens are a group of chemical elements that includes chlorine, bromine and iodine. As part of this research, Østerstrøm looked at three different types of eruption scenarios, which she simulated for two different seasons and at six different latitudes spanning the range of global latitudes that have volcanoes. A total of 36 different scenarios were run. “We found that the main influences on an eruption’s impact are the latitude and halogen content of its volcanic gases, whereas the season that the eruption takes place plays a smaller role,” says Østerstrøm.
Volcanoes and stratospheric composition
When the Hunga volcano erupted in 2022, Østerstrøm shifted the focus of her research to describing the global stratospheric changes and impacts seen in the first year following the eruption. “Here we showed how the observed stratospheric composition, chemistry and global water vapour all changed following the eruption,” adds Østerstrøm. This research is the focus of an upcoming World Climate Research Programme report on the eruption’s global impacts, which in turn will serve as a key source of information in the next World Meteorological Organization ozone report. Østerstrøm herself is co-leading a chapter on stratospheric chemistry and composition impacts.
Studying how future volcanic eruptions could impact the atmosphere and climate
The project, which received support from the Marie Skłodowska-Curie Actions programme, helped resolve the question of how sensitive the ozone is to volcanic eruptions. “This information can be used to describe, for example, how to better include volcanic eruptions and their impact in future evaluations of ozone recovery trends,” notes Østerstrøm. In addition to continuing her work on modelling and researching the Hunga eruption, Østerstrøm plans to further investigate how future eruptions could impact both the atmosphere and the climate. “The next challenge is to study other sudden changes to stratospheric composition that can influence human health, the environment and climate,” she concludes. Østerstrøm’s research has been published in several leading scientific journals, with one article receiving the highest attention scores as tracked by Altmetric.
Keywords
SOLVE, volcano, volcanoes, volcanic eruption, ozone layer, climate, climate change, stratosphere, atmosphere
