Atmospheric impacts of Hunga volvanic eruption

The eruption of the Hunga volcano in the South Pacific on 15^th January 2022 produced the largest underwater explosion ever recorded by modern scientific instruments. It injected vast quantities of water vapor into the stratosphere, increasing global stratospheric water by about 10%, much of which remains in the atmosphere through 2025.

After 4 years of work, the World Climate Research Programme (WCRP), which is co-sponsored by the World Meteorological Organisation (WMO), delivered a landmark report on the global atmospheric impacts of the Hunga eruption. This international assessment, through the Atmospheric Processes And their Role in the Climate (APARC) project, brought together 159 scientists from 21 countries.  The report’s seven chapters synthesize findings from observations, data analyses, and climate model simulations. It includes contributions from the Hunga Tonga–Hunga Haʻapai Impact Model Observation Comparison (HTHH-MOC) project – an international modeling effort involving more than ten global climate models (Zhu et al., 2025).

HYGEOS contributed to the HTHH-MOC project with simulations from the ECMWF IFS-COMPO global atmospheric composition model.  This work showed that IFS-COMPO manages to represent well the role of water vapour in the enhancement of particulate sulfate production, which is a specific feature of the Hunga eruption as compared to e.g. the Raikoke or the Pinatubo eruptions. It also allowed for numerous tests and improvements of the volcanic injection code of IFS-COMPO. This leads to future improvements in the representation of large volcanic events by the Copernicus Atmosphere Monitoring Service (CAMS) that uses IFS-COMPO for its operational production.

The report can be found at: https://aparc-climate.org/publications/aparc-report-no-11/