Volcano Eruption Helps Scientists Predict Weather and Climate Change

The eruption of the Hunga Tonga-Hunga Ha'apai volcano in Tonga has allowed scientists to better study how the atmosphere works, enabling them to predict how the changing climate will affect future weather.

The underwater volcano became active in December 2021 and eventually erupted on January 15, 2022. In the weeks leading up to the eruption, the volcano began to spew a dense plume of black ash, sulfur dioxide and steam. When the volcano erupted in one of the biggest volcanic events in modern history, it destroyed many homes on nearby islands with 100,000 times more energy than the Hiroshima nuclear bomb, sent out a pressure wave that circled the globe multiple times, and produced a cloud of ejecta that towered over 30 miles high.

Research published in the journal Nature has shown the scale of the force produced by the eruption. According to the paper, a broad spectrum of atmospheric waves was triggered by the initial explosion, including Lamb waves traveling at around 715 mph at surface level and in the stratosphere, and gravity waves going up to 600 mph in the stratosphere.

This is the first time that gravity waves have been observed traveling at these speeds at heights below the ionosphere.

The study's lead author, Corwin Wright, of the Centre for Space, Atmospheric and Oceanic Science at the University of Bath in the U.K., said in a news release:

"This was a genuinely huge explosion, and truly unique in terms of what's been observed by science to date. We've never seen atmospheric waves going around the whole world before, or at this speed—they were traveling very close to the theoretical limit."

While the Lamb waves produced by the eruption were atmospheric pressure pulses, a type of acoustic wave trapped at the Earth's surface moving only in a horizontal direction, the gravity waves move up and down, oscillating stable atmospheric layers like a pebble in a pond.

These gravity waves were actually visible to the naked eye via their effects on the clouds, and according to a video released by co-author of the paper Cathy Clerbaux, from France's Sorbonne University, were caught on camera at an observatory in Hawaii.

"Some of the wave types the Hunga Tonga generated are very important to understanding how the atmosphere works and our ability to make effective computer models for weather forecasting and climate projections," Mathew Barlow, a faculty member in UMass Lowell's Climate Change Initiative, told local Massachussets news source the Lowell Sun. "Through the expulsion of particles into the high atmosphere, some strong eruptions can also have a cooling effect on the climate, though the amount produced by Hunga Tonga does not appear sufficient for a notable climate effect, unlike other volcanic eruptions over the last century, like the Pinatubo eruption in 1991."

Volcanoes throughout geological history have had major impacts on the planet's climate, decreasing surface temperature, increasing stratospheric temperature, suppressing global water cycle, and weakening monsoon circulation. According to the paper, the researchers see the Hunga Tonga eruption as an ideal case study into how the atmosphere responds to a "sudden point-source-driven state change", which they plan to use in weather and climate models in the future.