When Mount Ruang in Indonesia suffered multiple explosive eruptions last week, volcanic gases were released so high that they reached the second layer of the atmosphere, tens of thousands of meters above the ground.
The force of Mount Ruang’s eruptions this week ejected an ash cloud tens of thousands of feet into the air and sent some volcanic gases more than 65,000 feet into the air, according to satellite estimates – about 25,000 feet higher than a commercial airliner typically flies.
The potential impacts of the eruption on weather and climate are beginning to become evident, even as the danger posed by the volcano persists and evacuations continue.
It is possible that volcanoes have a short-term impact on climate – including cooling global temperatures – due to the gases they inject into the upper atmosphere. But Mount Ruang’s influence on climate will likely be minimal, according to Greg Huey, chair of Georgia Tech’s School of Earth and Atmospheric Sciences.
And daily weather conditions near Mount Ruang — things like temperature, clouds and rain — likely won’t be influenced by the volcano for long, Huey told CNN.
Mount Ruang, a 2,400-foot (725-meter) stratovolcano on Ruang Island in Indonesia’s North Sulawesi province, has erupted at least seven times since Tuesday night, the the country’s volcanology agency said. Stratovolcanoes can produce explosive eruptions because their cone shape allows gas to accumulate, according to volcanologists.
Volcanic ash is typically a mixture of crushed solids – including rocks, minerals and glass – and gases, such as water vapor, carbon dioxide and sulfur dioxide, according to NASA.
“The ash itself is short-lived in the atmosphere because it’s heavy, it’s large and it tends to settle quickly,” Huey told CNN. These are the gases that can reach much higher levels in the atmosphere.
Dense ash near the surface creates dangerous air quality and causes a temporary cooling effect as it blocks warming sunlight. Once the active eruption stops, the ash begins to settle.
Some gases from Mount Ruang’s eruptions rose so high that they reached the stratosphere, the second layer of Earth’s atmosphere. It is located just above the troposphere, where all life and climate occur.
The stratosphere is a very dry place and typically only gases with a long lifespan — spanning decades — are filtered into it, according to Huey. A volcanic eruption is essentially the only natural way for short-lived gases – less than a few years – like sulfur dioxide and water vapor to reach the stratosphere.
Once in the stratosphere, sulfur dioxide and water vapor combine to form sulfuric acid aerosols that create a layer of hazy droplets, according to UCAR. These droplets spread far from their point of entry and remain in the stratosphere for up to three years, reflecting sunlight back into space and causing global temperatures to cool.
But the cooling effect lasts longer if more gas reaches the stratosphere.
In 1991, Mount Pinatubo – another stratovolcano – erupted in the Philippines and produced the largest sulfur dioxide plume ever measured. The eruption spilled more than 17 million tons of gas into the atmosphere and led to a decrease in global temperature of about 0.5 degrees Celsius (0.9 degrees Fahrenheit) that lasted about a year, according to the United States Geological Survey. U.S.
By comparison, satellite instruments estimated that Mount Ruang released about 300,000 tons of sulfur dioxide so far, although it’s unclear how much of that plume reached the stratosphere. While that amount is pretty huge on its own, it falls far short of the most extreme case, according to Huey.
An eruption as large as Mount Pinatubo in 1991 could certainly cool the planet for a few years, although it would not be able to erase Earth’s radiation. current climate problems caused by planet-warming pollution, and would come at the cost of enormous damage to life and property.
CNN’s Kathleen Magramo contributed to this report.
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