Context: The eruption of the underwater volcano Hunga Ha’apai off Tonga in 2022. The volcano has had weather altering impact across the globe.
About Hunga Tonga–Hunga Haʻapai
- It is under water volcano eruption (Submarine volcano)
- It is part of the highly active Kermadec-Tonga subduction zone
- It is associated with volcanic arc, which extends from New Zealand north-northeast to Fiji.
- It is formed by the subduction of the Pacific Plate under the Indo-Australian Plate.
Unusual Eruption
- Unlike typical volcanic eruptions, Hunga Tonga, an underwater volcano, emitted minimal smoke but significant water vapor (100-150 million tonnes).
- Water vapor ascended into the stratosphere, a dry layer 15-40 km above the surface, which usually lacks clouds and rain.
Stratospheric Effects
- Water vapor in the stratosphere contributes to ozone layer depletion and acts as a potent greenhouse gas. (Water vapor in stratosphere leads to release of active OH which in turn reacts with ozone to form oxygen and monoatomic oxygen)
Modeling Future Climate
- Two simulations compared: one with the eruption's water vapor injection and one without eruption of water vapor.
Findings
- August-December 2023 witnessed a large ozone hole partially attributed to Hunga Tonga.
- Predicted the ozone hole's enlargement two years in advance; subsequent years unlikely to be impacted.
- Positive Southern Annular Mode in summer 2024 led to unexpected wetter conditions in Australia contrary to El Niño expectations.
- Global mean temperature impact negligible (0.015°C).
Long-term Regional Impacts
- Northern Australia to experience colder, wetter winters until approximately 2029.
- North America anticipates warmer winters, while Scandinavia expects colder ones.
- Volcanic eruption influences atmospheric wave dynamics, impacting weather patterns.
Study presents one perspective; acknowledges limitations and welcomes further research.