Volcanoes around the world continuously exhale ash and water vapor laced with heavy metals, carbon dioxide, hydrogen sulfide, and sulfur dioxide. Researchers from Michigan Technological University created the first, truly global inventory for volcanic sulfur dioxide emissions.

The measurements were calculated using data from the Dutch-Finnish Ozone Monitoring Instrument on NASA’s Earth Observing System Aura satellite, launched in 2004.

The team compiled emissions data from 2005 to 2015 to produce annual estimates for each of 91 presently emitting volcanoes worldwide. The data set will help to refine climate and atmospheric chemistry models and provide insight into human and environmental health risks.

“Many people may not realize that volcanoes are continuously releasing quite large amounts of gas, and may do so for decades or even centuries,” said volcanologist Simon Carn, an associate professor at Michigan Tech in Houghton, Michigan, and the lead author of the new study, published this month in Scientific Reports. “Because the daily emissions are smaller than a big eruption, the effect of a single plume may not seem noticeable, but the cumulative effect of all volcanoes can be significant.

Carn and his team found that each year volcanoes collectively emit 20 to 25 million tons of sulfur dioxide into the atmosphere. The new research includes data on a greater number of volcanoes, including some that scientists have never visited.

With daily observations, tracking sulfur dioxide emissions via satellite can additionally assist researchers with eruption forecasting. Along with measuring seismic activity and ground deformation, scientists monitoring satellite data can potentially detect increases in gas emissions that may precede eruptions.


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