Study shows impacts of Hunga Tonga-Hunga Ha’apai eruption can have surface impacts on a decadal timescale

A new study published in the Journal of Climate explored the impacts of the massive eruption of Hunga Tonga-Hunga Ha’apai in 2022, and highlighted significant effects on winter weather patterns across multiple continents, with impacts expected to last for several years.

The eruption of Hunga Tonga-Hunga Ha’apai (HTHH) on January 15, 2022, in Tonga caused significant changes in global climate patterns by injecting between 100 million and 150 million tons of water vapor into the stratosphere. This amount, equivalent to 60 000 Olympic swimming pools, was unprecedented and has led to notable long-term effects, according to a study published in the Journal of Climate.

The study utilized chemistry climate model simulations to explore the impacts of such a large-scale water vapor injection. Unlike typical volcanic eruptions that release sulfur dioxide leading to temporary surface cooling, the HTHH eruption’s water vapor resulted in persistent and significant climate alterations.

One of the immediate and measurable impacts was the unusually large ozone hole observed from August to December 2023. The water vapor facilitated the formation of this ozone hole by reaching the polar stratosphere over Antarctica. The study’s simulations predicted this outcome nearly two years in advance.

Additionally, the eruption influenced the Southern Annular Mode, leading to an unexpectedly wet summer in Australia during 2024, despite the prevailing El Niño conditions. The study also noted that the global mean temperature impact was minimal, at approximately 0.015 °C, indicating that recent high temperatures cannot be attributed to the HTHH eruption.

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The study predicts that the climatic disturbances caused by the HTHH eruption will persist for the rest of the decade, particularly affecting winter weather patterns. For the northern half of Australia, colder and wetter winters are expected until around 2029. In contrast, North America is predicted to experience warmer than usual winters, while Scandinavia will see colder winters.

These changes are attributed to the altered behavior of atmospheric waves, which play a crucial role in weather patterns. The disruption caused by the vast amount of water vapor in the stratosphere has led to significant shifts in these atmospheric waves.

The findings from the Journal of Climate study highlight the need for further research to understand the full implications of large stratospheric water vapor anomalies on global climate.

While the study provides significant insights, it acknowledges limitations, such as not accounting for other climatic phenomena like the El Niño–La Niña cycle.

This study is a call to the scientific community to explore the long-term effects of such unprecedented events. As climate models continue to evolve, future research will either confirm or challenge these initial findings, contributing to a deeper understanding of volcanic impacts on climate.

References:

¹ Long-term climate impacts of large stratospheric water vapor perturbations – Martin Jucker, Chris Lucas, and Deepashree Dutta – Journal of Climate – American Meteorological Society – May 27, 2024 – DOI: https://doi.org/10.1175/JCLI-D-23-0437.1

Featured image: Ash produced by Hunga Tonga-Hunga Haapai eruption on January 16, 2024. Credit: NASA