SUMMARY: Volcanoes play an important role in recycling carbon dioxide. This study takes a closer look at the amount emitted into the atmosphere by volcanoes that aren’t underwater. Out of 900 volcanoes, only 500 have detectable degassing activity (i.e. they are emitting gases). One hundred and twenty-five are strong emitters, 144 are weak emitters, the other 756 are either very weak emitters or have no data. Since researchers cannot directly measure CO2, they must first measure SO2 (via satellite imaging). Using previously-obtained C/S (carbon to sulfur) ratios from other studies, CO2 emissions are calculated. For volcanoes with unmeasured C/S, the ratio is inferred based on the tectonic position of the volcano. Scientists can use information from either subducted slab-derived fluids or look at the amount of overlying crust to make an inference. Turns out, active, explosive volcanoes do not contribute that much CO2. In fact, volcanic CO2 represents about 0.02% of anthropogenic emissions.
LESSON COMMENTS: This article gives teachers more information about volcanoes and volcano research. It can be used in Earth Science or Environmental Science classes. Since volcano activity is constantly changing, it’s important to note that the researchers talk about the need to update these measurements regularly. For applications in the classroom, the methodology of this experiment is particularly interesting. Are there certain things that we can’t measure, but must infer indirectly? There is some basic mathematical concepts in this article that can also be used in an interdisciplinary class (math and science). The article is easy enough to read for younger students, specifically the abstract and conclusion section. High school students should have no problems with the introduction and can read this on their own.
Fischer, T. P., Arellano, S., Carn, S., Aiuppa, A., Galle, B., Allard, P., … Chiodini, G. (2019). The emissions of CO2 and other volatiles from the world’s subaerial volcanoes. Scientific reports, 9(1), 18716. doi:10.1038/s41598-019-54682-1