The eruption of the Hunga Tonga-Hunga Ha’apai volcano in Tonga on January 15, 2022 was an incredible natural event with widespread and far-reaching consequences. The eruption not only generated a devastating tsunami but also generated sound waves around the world and released unprecedented amounts of water vapor into the stratosphere. A study recently published in the Journal of Climate examines the long-term climate impacts of this volcanic eruption. The study showed that the January 2022 eruption of the Hunga Tonga-Hunga Ha’apai volcano had a significant impact on global weather patterns.
Hunga Tonga-Hunga Ha’apai Volcano
- It is an Undersea Volcanic Eruption consisting of two small uninhabited islands, Hunga-Ha’apai and Hunga-Tonga.
- The volcano has erupted regularly over the past few decades.
- This is one of the massive explosions the volcano is capable of producing roughly every thousand years.
- One of the reasons for it being highly explosive is the Fuel-Coolant interaction.
- The Hunga Tonga eruption’s unique characteristic of injecting massive water vapour into the stratosphere.
- Usually, volcanic smoke, which mostly contains sulphur dioxide, leads to a temporary cooling of the Earth’s surface.
- The sulphur dioxide turns into sulphate aerosols, which reflect sunlight into space, causing the surface to cool down until the sulphate settles back on the surface or is washed out by rain.
Effects of the Hunga-Tonga Volcano on the Climate
Extraordinary Ozone Hole in 2023
- Since, Hunga Tonga is an underwater volcano, it produced 100-150 million tonnes of water vapour during its eruption, raising the amount of water in the stratosphere by around 5%.
- This water vapour in the stratosphere contributes to the destruction of the ozone layer and acts as a potent greenhouse gas.
- The study found that the large ozone hole observed from August to December 2023 was at least partly due to the Tonga eruption.
- This ozone hole was almost two years in advance, as the water vapour from the eruption had enough time to reach the polar stratosphere over Antarctica.
Wet Summer of 2024 in Australia
- The model predicted a positive phase of the Southern Annular Mode during the summer of 2024, leading to a higher chance of a wet summer in Australia.
- This was contrary to the expected El Niño conditions, and the model was able to forecast this two years in advance.
Regional Weather Disruptions
- The study predicts colder and wetter than usual winters for the northern half of Australia up to around 2029.
- North America may have warmer than usual winters, while Scandinavia can have colder than usual winters.
- These regional weather patterns are attributed to the Tonga eruption’s impact on the way atmospheric waves travel, which directly influences local weather conditions.
- This emphasises the need for region-specific climate predictions and adaptation strategies.
Minimal Impact on Global Temperatures
- The impact of the eruption on global mean temperatures was very small, around 0.015°C.
- The incredibly high temperatures observed for about a year cannot be attributed to the Tonga eruption.
Undersea Volcano
- The undersea volcanic eruption happens in a volcano which is located under the ocean surface. There are an estimated one million undersea volcanoes, and most of them are located near the tectonic plates.
- Apart from lava, these openings also spew out ash. These deposit on the ocean’s floor and lead to the formation of sea mounds (underwater mountains that are formed on the ocean floor but do not reach the water surface).
Fuel-Coolant Interaction
- If magma rises into seawater slowly, even at temperatures of about 1200 degrees Celsius, a thin film of steam forms between the magma and water. This provides a layer of insulation to allow the outer surface of the magma to cool. But this process doesn’t work when magma is blasted out of the ground full of volcanic gas.
- When magma enters the water rapidly, any steam layers are quickly disrupted, bringing hot magma in direct contact with cold water. It is akin to weapons-grade chemical explosions.
- Extremely violent blasts tear the magma apart.
- A chain reaction begins, with new magma fragments exposing fresh hot interior surfaces to water, and the explosions repeat, ultimately jetting out volcanic particles and causing blasts with supersonic speeds.