The average contribution of SO2 to the atmosphere by volcanoes, estimated largely by extrapolation from direct measurements of volcanic SO2, is calculated to be 18.7 Tg per year. Of this, an estimated 6.8 Tg per year (36%) is from non-erupting degassing volcanoes. Erupting volcanoes yield an average annual flux estimated to be 11.9 Tg SO2 per year (64%). The estimated total annual SO2 output is about 23% larger than the most recent estimate based on direct measurements. Our calculations suggest that 64% of the total comes from erupting volcanoes, as compared to 7% in the earlier estimate. Of the total worldwide annual SO2 flux, 9% is found to be from volcanoes.
ASJC Scopus subject areas
- Geochemistry and Petrology