When looking at diffuse degassing, the researchers found one area that measured less than a tenth of a square mile, yet emits 150 tons of carbon dioxide per day. The researchers note that Mt. Etna, a volcano which produces 35,000 tons of carbon dioxide per day and is the largest single source of natural carbon dioxide in the world, is located in this area of Italy. Unlike many other volcanoes, Etna is not in an area where tectonic plates meet. Assuming that most carbon dioxide in the past came from areas of subduction vulcanism may not be the way to model carbon dioxide production, according to the researchers. There is a great deal of gas coming from carbon dioxide vents and the area around these vents that must be taken into consideration.
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