An underwater volcanic eruption filled stratosphere with 150 metric tonnes of water vapour. Here's how

New Delhi, India

A high-intensity eruption occurred in the underwater volcano Hunga Tonga–Hunga Ha'apai on January 15, 2022, which led to a powerful tsunami throughout Tonga. 

But this event also had another lasting effect which was the launch of high amounts of aerosol and water vapor plumes towards the sky. This was the largest underwater explosion to have ever been recorded by modern scientific instruments.

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The scientists examined how the eruption of Volcano Hunga impacted the climate in the Southern Hemisphere in the next two years.

Here's how volcanic eruption impacted climate

The scientists discovered that there was a stronger cooling effect from volcanic aerosols reflecting sunlight into outer space after the eruption in comparison to the warming that happened because of heat getting trapped by the water vapours in the atmosphere.

However, by the end of 2023, more of the effects of the volcano had dissipated.

Satellite data was used by the researchers to examine how stratospheric aerosols, gases, and temperatures had changed after the eruption. 

It was discovered that the Hunga eruption poured 150 metric megatons of water vapour into the stratosphere. This is a very high amount and has increased global levels of stratospheric water vapour by about 10 per cent.

In the tropical stratosphere, the massive water injection led to the cooling of temperatures by 4°C in March and April of 2022. 

The temporary cooling led to the formation of a secondary circulation pattern because of which ozone levels started reducing throughout 2022.

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The Hunga eruption also led to the release of 0.5 and 1.5 metric megatons of sulfur dioxide into the stratosphere. 

Sulfur dioxide produces sulfate aerosols which reflect sunlight and can lead to a reduction in surface radiative forcing or the difference between outgoing and incoming radiation. 

This can also cause global cooling if enough amount of aerosol is loaded as was the case in the 1991 eruption of Mount Pinatubo, during which 20 metric megatons of sulfur dioxide was released.

The Hunga aerosol load was not huge and had confined effects on the Southern Hemisphere in 2022 and 2023.

(With inputs from agencies)