A team of atmospheric specialists recently published their research in the journal Science, revealing the significant impact of the 2022 eruption of the Hunga-Tonga Hunga-Ha’apai volcano. This eruption was exceptional due to its injection of substantial water vapor into the stratosphere. The researchers found that this event led to a rapid and substantial ozone loss (O3).

To investigate this phenomenon, the scientists conducted balloon-based measurements, zenith sky observations, and analyzed satellite data. Within just one week of the eruption, the ozone levels in the stratosphere above the tropical southwestern Pacific and Indian Ocean region dropped by 5%, exceeding the impact of previous volcanic eruptions. The research highlights the role of water vapor in triggering this ozone loss, as increased humidity and radiative cooling in the stratosphere allowed for chemical reactions on volcanic aerosols’ surfaces to occur at higher temperatures than usual.

The study’s findings revealed that water vapor played a critical role in the ozone depletion. The enhanced humidity and radiative cooling in the stratosphere facilitated chemical reactions on the surfaces of volcanic aerosols. These reactions led to the formation of active chlorine species, including chlorine monoxide (ClO), which catalytically destroyed ozone molecules. This process was further supported by the decrease in hydrogen chloride (HCl) and the increase in ClO within the volcanic plume. The data uncovered the intricate interplay between volcanic emissions and stratospheric chemistry, elucidating the mechanisms responsible for the observed ozone depletion.

In addition to its volcanic relevance, this research has broader implications for atmospheric chemistry and climate change. The study provides crucial insights into the complex interactions between large volcanic eruptions and stratospheric ozone, advancing our understanding of rapid ozone depletion in specific volcanic plumes. It also offers new perspectives on the effects of volcanic eruptions on stratospheric composition, informing future research and early-response strategies to assess their consequences. The study underscores the importance of understanding how such eruptions can impact the Earth’s atmosphere and climate.

References

• Evan, S., Brioude, J., Rosenlof, K. H., Gao, R.-S., Portmann, R. W., Zhu, Y., Volkamer, R., Lee, C. F., Metzger, J.-M., Lamy, K., Walter, P., Alvarez, S. L., Flynn, J. H., Asher, E., Todt, M., Davis, S. M., Thornberry, T., Vömel, H., Wienhold, F. G., … Read, W. G. (2023). Rapid ozone depletion after humidification of the stratosphere by the Hunga Tonga Eruption. Science, 382(6668), eadg2551. https://doi.org/10.1126/science.adg2551
• Yirka, B. & Phys.org. (2023, October 20). New study shows Hunga-Tonga Hunga-Ha’apai eruption depleted ozone layer. Phys.Org. https://phys.org/news/2023-10-hunga-tonga-hunga-haapai-eruption-depleted-ozone.html