A massive underwater volcanic eruption in January this year in the South Pacific Ocean may temporarily affect Earth’s climate patterns, a study has found.
Volcanic eruption of Tonga
The Hunga Tonga-Hunga Ha’apai volcano, which erupted on January 15 this year, sent a tsunami around the world and caused a sonic boom that circled the world twice.
The undersea eruption in the South Pacific Ocean also launched a huge plume of water vapor into Earth’s stratosphere, enough to fill more than 58,000 Olympic-sized swimming pools.
How Tonga’s Volcanic Eruption Could Affect Earth’s Temperature
The large amount of water vapor released in the volcanic eruption could be enough to temporarily affect the Earth’s global average temperature.
According to NASA, the water vapor released in the volcanic eruption could end up temporarily warming the Earth’s surface.
What is unprecedented about the volcanic eruption in Tonga
Volcanic eruptions rarely inject much water into the stratosphere. In the 18 years NASA has been taking measurements, only two other eruptions—the 2008 Kasatochi event in Alaska and the 2015 Calbuco eruption in Chile—sent appreciable amounts of water vapor to such high altitudes.
But those were mere blips compared to the Tonga event, and the water vapor from the previous two eruptions quickly dissipated. The excess water vapor injected by the Tonga volcano, on the other hand, could remain in the stratosphere for several years.
This extra water vapor could influence atmospheric chemistry, increasing certain chemical reactions that could temporarily worsen ozone depletion. It could also influence surface temperatures.
Warming effect from Tonga volcanic eruption may dissipate over time
Massive volcanic eruptions like Krakatoa and Mount Pinatubo often cool the Earth’s surface by spewing gases, dust and ash that reflect sunlight into space. In contrast, Tonga Volcano did not inject large amounts of aerosols into the stratosphere, and the large amounts of water vapor from the eruption may have a small temporary warming effect as the water vapor traps the heat.
The effect would dissipate as the additional water vapor left the stratosphere and would not be sufficient to significantly exacerbate the effects of climate change.
Correct depth in the ocean
The large amount of water injected into the stratosphere was only possible because the submarine volcano’s caldera, a basin-like depression that typically forms after magma erupts or drains from a shallow chamber beneath the volcano, was at the proper depth in the ocean: approx. 490 feet (150 meters) down.
Deeper, and there would not have been enough seawater superheated by erupting magma to account for the stratospheric water vapor values observed by a team of NASA researchers, and deeper, and the immense pressures at the depths of the ocean could have silenced the eruption. .
146 Teragrams of water vapor injected into the stratosphere
“We’ve never seen anything like it,” said Luis Millán, an atmospheric scientist at NASA’s Jet Propulsion Laboratory in Southern California.
He led a new study that examined the amount of water vapor the Tonga volcano injected into the stratosphere, the layer of the atmosphere between about 12 and 53 kilometers above the Earth’s surface.
In the study, published in Geophysical Research Letters, Millán and his colleagues estimate that the Tonga eruption sent about 146 teragrams (1 teragram equals a trillion grams) of water vapor into the stratosphere of the Earth, equivalent to 10% of the water already present in it. atmospheric layer
That’s nearly four times the amount of water vapor scientists estimate the 1991 eruption of Mount Pinatubo in the Philippines lifted into the stratosphere.
Millán analyzed data from the Microwave Limb Sounder (MLS) instrument on NASA’s Aura satellite, which measures atmospheric gases, including water vapor and ozone.
After the Tonga volcano erupted, the MLS team started seeing water vapor readings that were off the charts.
“We had to carefully inspect all plume measurements to make sure they were reliable,” Millán said.
The MLS instrument was well placed to detect this plume of water vapor because it observes natural microwave signals emitted from Earth’s atmosphere. Measuring these signals allows the MLS to “see” through obstacles like ash clouds that can blind other instruments that measure water vapor in the stratosphere.
“MLS was the only instrument with dense enough coverage to capture the water vapor plume as it happened, and the only one that was not affected by the ash released by the volcano,” he say Millán