The Hunga Tonga eruption caused a plume that reached the mesosphere. Credit: NASA

Tonga Eruption Injected 146 billion Kilograms of Water Vapor Into the Atmosphere

It is estimated that the Tonga eruption injected around 146 teragrams of water vapor into the stratosphere - approximately 10% of the water already present in this layer. (1 teragram equals a trillion grams). Enough to fill more than 58,000 Olympic-size swimming pools.


As NASA’s Microwave Limb Sounder detected, the massive amount of water vapor released by the Tonga Explosion into our planet’s atmosphere could temporarily warm the Earth.

An eruption of the Hunga Tonga-Hunga Ha’apai volcano on Jan. 15 set off a sonic boom that circled the globe twice and sent a tsunami racing around the world.


A massive plume of water vapor was also released into Earth’s stratosphere by the underwater eruption in the South Pacific Ocean – enough to fill more than 58,000 Olympic-size swimming pools. The sheer amount of water vapor could be enough to affect Earth’s global average temperature temporarily.

“We’ve never seen anything like it,” said Luis Millán, an atmospheric scientist at NASA’s Jet Propulsion Laboratory in Southern California.

New research led by Millán examined the amount of stratospheric water vapor injected by the Tonga volcanic eruption. The stratosphere lies between 8 and 33 miles (12 to 53 kilometers) above the planet’s surface.

It is estimated that the Tonga eruption injected around 146 teragrams of water vapor into the stratosphere – approximately 10% of the water already present in this layer. (1 teragram equals a trillion grams)

It’s almost four times as much water vapor as scientists estimate Mount Pinatubo’s 1991 eruption produced in the stratosphere.

Millán used data collected by NASA’s Aura satellite’s Microwave Limb Sounder (MLS), which measures atmospheric gases, including water vapor and ozone. Water vapor readings skyrocketed after the Tonga volcano erupted.

“We had to carefully inspect all the measurements in the plume to make sure they were trustworthy,” explained Millán.


The stratosphere is rarely filled with water as a result of volcanic eruptions. NASA has taken measurements for 18 years, and only two other eruptions have sent water vapor to such high altitudes – the 2008 Kasatochi event in Alaska and the 2015 Calbuco eruption in Chile.

Compared with the Tonga eruption, those were mere blips, and the water vapor from both eruptions dissipated quickly. On the other hand, the excess water vapor injected by the Tonga volcano could remain in the stratosphere for many years.

By increasing atmospheric water vapor, certain chemical reactions might be boosted, thereby temporarily worsening the depletion of the ozone layer. In addition, it could affect the temperature of the surface.

As gases, dust, and ash are emitted by massive volcanic eruptions like Krakatoa and Mount Pinatubo, they reflect sunlight back into space, thereby cooling the Earth’s surface.

By contrast, the Tonga volcano injected little aerosol into the stratosphere but did send huge amounts of water vapor. The water vapor trapped heat, so it could have a small warming effect for a short period of time.

Climate change effects would not be exacerbated noticeably by the extra water vapor cycling out of the stratosphere after about a year.

Water was injected into the stratosphere only because a caldera under the volcano was at approximately 490 feet (150 meters) below sea level. It usually forms when magma erupts or drains from a shallow chamber beneath the volcano.

The stratospheric water vapor values Millán and his colleagues observed would not have been possible if it was any shallower.

If the eruption had been any deeper, the immense pressures in the ocean would have muted it.


Since MLS observes natural microwave signals emitted by Earth’s atmosphere, it was well positioned to detect this water vapor plume. This technology allows MLS to measure water vapor in the stratosphere even in the presence of obstacles like ash clouds without being blinded by them.

“MLS was the only instrument with dense enough coverage to capture the water vapor plume as it happened, and the only one that wasn’t affected by the ash that the volcano released,” said Millán.

The study was published in Geophysical Research Letters.

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Written by Ivan Petricevic

I've been writing passionately about ancient civilizations, history, alien life, and various other subjects for more than eight years. You may have seen me appear on Discovery Channel's What On Earth series, History Channel's Ancient Aliens, and Gaia's Ancient Civilizations among others.

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