Volcano eruption in Tonga released enough water to fill 58,000 swimming pools

One of the most powerful volcanic eruptions on the planet has blasted such a large amount of water vapor into the atmosphere that it will likely temporarily warm the Earth’s surface, according to detections by a NASA satellite.

When the Hunga Tonga-Hunga Ha’apai undersea volcano erupted on January 15, 65 km north of the capital city of Tonga, it created a tsunami and a sonic boom that spread across the world – twice.

The eruption sent a high cloud of water vapor into the stratosphere, located between 12 and 53 km above the Earth’s surface. It was enough water to fill 58,000 Olympic swimming pools, according to detections from a NASA satellite.

The detection was made by the Microwave Limb Sounder instrument on NASA’s Aura satellite. The satellite measures water vapour, ozone and other atmospheric gases. After the eruption took place, scientists were stunned by the water vapor readings.

They estimate that the eruption delivered 146 teragrams of water into the stratosphere. A teragram is equivalent to a trillion grams and, in this case, it was equal to 10% of the water already present in the stratosphere.

That’s nearly four times the amount of water vapor that reached the stratosphere after the 1991 eruption of Mount Pinatubo in the Philippines.

A new study of the water vapor findings was published in July in the journal Geophysical Research Letters.

“We’ve never seen anything like it,” study author Luis Millán, an atmospheric scientist at NASA’s Jet Propulsion Laboratory in southern California, said in a statement. “We had to carefully inspect all measurements on the plume to ensure they were reliable.”

eyeing the earth

The Microwave Limb Sounder instrument can measure natural microwave signals from the Earth’s atmosphere and detect them even through thick ash clouds.

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

The Aura satellite was launched in 2004 and has since measured only two volcanic eruptions that have released substantial water vapor so high into the atmosphere. But water vapor from the 2008 Kasatochi event in Alaska and the 2015 Calbuco eruption in Chile quickly dissipated.

Typically, powerful volcanic eruptions like Mount Pinatubo or the 1883 Krakatoa event in Indonesia cool the Earth’s surface temperature because the gas, dust and ash they spew reflect sunlight into space. This “volcanic winter” followed the eruption of Mount Tambora in 1815, triggering “the year without a summer” in 1816.

The Tonga eruption was different because water vapor sent into the atmosphere can trap heat, which can cause warmer surface temperatures. Excess water vapor can remain in the stratosphere for several years, according to the researchers.

Additional water vapor in the stratosphere can also lead to chemical reactions that temporarily contribute to the depletion of Earth’s protective ozone.

Anatomy of a rash

Fortunately, the heating effect of the water vapor is expected to be small and temporary, and will dissipate as the extra vapor subsides. The researchers do not believe it will be enough to worsen existing conditions due to the climate crisis.

The researchers believe the main reason for the high amount of water vapor was the depth of the volcano’s caldera, 150 meters below the ocean’s surface.

If it was too deep, the depth of the ocean would have silenced the eruption, and if it was too shallow, the amount of seawater heated by the erupting magma would not match what reached the stratosphere, the researchers said.

Scientists are still working to understand the extraordinarily energetic eruption and all its superlatives, including hurricane-force winds that hit space.