NASA satellite data shows that the volcano released more than 146 teragrams of water, enough to fill 58,000 Olympic swimming pools, into the second layer of Earth’s atmosphere, known as the stratosphere, where the ozone layer is located and just above from where planes fly The study indicated that the amount released is equivalent to 10 percent of the water that is already in the stratosphere.
“This is the first time this type of injection has occurred in the entire satellite era,” which includes water vapor data going back to 1995, said Luis Millán, lead author of the study and a NASA atmospheric scientist. “We’ve never seen anything like this before, so it was pretty impressive.”
Volcanic eruptions expel many different types of gases and particles. Most eruptions, including Hunga Tonga, release particles that cool the Earth’s surface by reflecting sunlight back into space, but these usually dissipate after two to three years. However, very few release water vapor that high. This water vapor can stay in the atmosphere longer (five to 10 years) and trap heat at the Earth’s surface.
Millán speculates that the water vapor could start to have a warming effect on the planet’s surface temperature once the accompanying cooling particles dissipate in about three years. He is not sure how much the temperature would rise, since it depends on how the column of water vapor evolves. The team suspects that increased warming will last for a few years, until circulation patterns in the stratosphere push water vapor into the troposphere, the layer where Earth’s weather is produced.
“This is just a temporary warm-up, and then it will go back to what it was supposed to go back to,” Millan said. “It’s not going to exacerbate climate change.”
NASA atmospheric scientist Ryan Kramer added that given the many factors that drive temperature changes on time scales of years, the volcano’s heating effect could also be lost in the noise, depending on its magnitude.
in a short On a time scale, increased water vapor could also worsen ozone depletion in the stratosphere, said Susan Strahan, an atmospheric chemist at the University of Maryland in Baltimore County and NASA.
Stratospheric ozone protects the Earth’s surface from harmful ultraviolet radiation. Chemicals that deplete the ozone layer were largely phased out through the 1987 Montreal Protocol and subsequent amendments.
Strahan, who was not involved in the study, explained that excess water vapor will affect many chemical reactions that control stratospheric ozone concentrations. NASA satellite data for July already shows a decline in ozone levels, compared to previous years, where excess water vapor is concentrated. He added that a full analysis would be necessary to discover the cause.
“There are probably impacts right now, but what we need [is] one model to tell us is by what mechanism(s) the impacts occurred. Almost certainly meteorology and chemistry will play a role: the questions are how much, where, when.” Strahan said in an email.
Strahan also said that excess water vapor could enhance the formation of special noctilucent clouds, which appear as glowing, ghostly wisps in the night sky. They occur about 50 miles into the atmosphere, higher than the stratosphere, and are some of the rarest, driest, tallest clouds on Earth. For many people, clouds provide an excellent view of the sky. Nevertheless, researchers think any noticeable changes in these clouds would not show up until later, depending on how long it takes for the water vapor to travel up into the atmosphere where the clouds form.
Overall, Millán said excess water vapor isn’t a cause for concern in and of itself, but “something that’s interesting that’s happening.” He and his colleagues are using this opportunity to test their computer models that help us understand climate change and weather forecasting in general.
“We have these massive amounts of water vapor moving in the stratosphere, and we can test how well the models reflect their movements within the atmosphere,” Millán said. “This volcano is going to give a lot of work to many researchers.”