Copied from the CO2 in the earth's atmosphere article
Drivers of ancient-Earth carbon dioxide concentration edit
On long timescales, atmospheric CO2 concentration is determined by the balance among geochemical processes including organic carbon burial in sediments, silicate rock weathering, and volcanic degassing. The net effect of slight imbalances in the carbon cycle over tens to hundreds of millions of years has been to reduce atmospheric CO2. On a timescale of billions of years, such downward trend appears bound to continue indefinitely as occasional massive historical releases of buried carbon due to volcanism will become less frequent (as earth mantle cooling and progressive exhaustion of internal radioactive heat proceed further). The rates of these processes are extremely slow; hence they are of no relevance to the atmospheric CO2 concentration over the next hundreds or thousands of years.
Copied from volcanic gas article.
Non-explosive volcanic gas release edit
The gas release can occur by advection through fractures, or via diffuse degassing through large areas of permeable ground as diffuse degassing structures (DDS). At sites of advective gas loss, precipitation of sulfur and rare mineralsforms sulfur deposits and small sulfur chimneys, called fumaroles. Very low-temperature (below 100 °C) fumarolic structures are also known as solfataras. Sites of cold degassing of predominantly carbon dioxide are called mofettes. Hot springs on volcanoes often show a measurable amount of magmatic gas in dissolved form.
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Current Emissions of Volcanic gases to the atmosphere edit
Present day global emissions of volcanic gases to the atmosphere can be characterized as emissions during eruptions and emissions during non-eruptive activity. Although all gases discussed above are emitted to the atmosphere, the emissions of sulfur dioxide (SO2) and carbon dioxide (CO2) have received the most study. Sulfur dioxide (SO2) emissions during eruptions were 2.6 tera grams (1012g or Tg) SO2/year [1] and during non-eruptive periods or passive degassing were 23.2 ± 2Tg SO2/year for the period from 2005 - 2015 [2] . It has long been recognized that the SO2 emissions during eruptions is much less than during passive degassing [3] [4]. Carbon Dioxide (CO2) emissions from volcanoes during eruptions were 1.8 ± 0.9 Tg CO2/year during the period from 2005 to 2015 [1]. CO2 emissions from volcanoes during non-eruptive activity were 51.3 ± 5.7 Tg CO2/year during the period from 2005 - 2015 [1]. Therefore CO2 emissions during volcanic eruptions are less than 10% of CO2 emissions released during non-eruptive volcanic activity. The VEI [5] 6 eruption of Pinatubo Volcano in the Philippines on June 15 1991 released a total of 18±4 Tg of SO2 [6]. Such large VEI [5] 6 eruptions are are rare and only occur once every 50 - 100 years. The 2010 VEI 4 Eyjaflallajökull eruption [7] in Iceland emitted a total of 5.1 Tg CO2 [8]. VEI 4 eruptions occur about once per year. For comparison, the human activity of burning fossil fuels and the production of cement has released 36,300 Tg CO2 into the atmosphere in 2015[9]. Therefore, the amount of CO2 emitted due to human activity is 600 times the amount of CO2 presently released by volcanoes. Some recent volcanic CO2 emission estimates that are higher than the ones listed above of 51.3 ± 5.7 and 1.8 ± 0.9 Tg CO2/year during non-eruptive and eruptive activity, respectively[1]. An estimate of 540 TgCO2/year [10] and an estimate of 220 - 300 TgCO2/year [11] take into account diffuse CO2 emissions from volcanic regions. Still, even considering the highest estimate of volcanic CO2 emissions of 540 Tg CO2/year [10], current CO2 emissions by human activity of 36,300 Tg CO2/year[9] is 67 times higher.
- ^ a b c d Fischer, Tobias P.; Arellano, Santiago; Carn, Simon; Aiuppa, Alessandro; Galle, Bo; Allard, Patrick; Lopez, Taryn; Shinohara, Hiroshi; Kelly, Peter; Werner, Cynthia; Cardellini, Carlo (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. ISSN 2045-2322. PMC 6904619. PMID 31822683.
{{cite journal}}: CS1 maint: PMC format (link) - ^ Carn, S. A.; Fioletov, V. E.; McLinden, C. A.; Li, C.; Krotkov, N. A. (2017). "A decade of global volcanic SO2 emissions measured from space". Scientific Reports. 7 (1): 44095. doi:10.1038/srep44095. ISSN 2045-2322. PMC 5343458. PMID 28275238.
{{cite journal}}: CS1 maint: PMC format (link) - ^ Berresheim, H.; Jaeschke, W. (1983). "The contribution of volcanoes to the global atmospheric sulfur budget". Journal of Geophysical Research. 88 (C6): 3732. doi:10.1029/JC088iC06p03732. ISSN 0148-0227.
- ^ Andres, R. J.; Kasgnoc, A. D. (1998-10-20). "A time-averaged inventory of subaerial volcanic sulfur emissions". Journal of Geophysical Research: Atmospheres. 103 (D19): 25251–25261. doi:10.1029/98JD02091.
- ^ a b Newhall, Christopher G.; Self, Stephen (1982). "The volcanic explosivity index (VEI) an estimate of explosive magnitude for historical volcanism". Journal of Geophysical Research. 87 (C2): 1231. doi:10.1029/JC087iC02p01231. ISSN 0148-0227.
- ^ Guo, Song; Bluth, Gregg J. S.; Rose, William I.; Watson, I. Matthew; Prata, A. J. (2004). "Re-evaluation of SO 2 release of the 15 June 1991 Pinatubo eruption using ultraviolet and infrared satellite sensors: SATELLITE STUDY OF 15 JUNE 1991 PINATUBO SO 2 RELEASE". Geochemistry, Geophysics, Geosystems. 5 (4): n/a–n/a. doi:10.1029/2003GC000654.
- ^ Smithsonian Institution (2013). Venzke, E (ed.). "Volcanoes of the World, v. 4.3.4". doi:10.5479/si.gvp.votw4-2013.
{{cite journal}}: Cite journal requires|journal=(help) - ^ Werner, Cynthia; Fischer, Tobias P.; Aiuppa, Alessandro; Edmonds, Marie; Cardellini, Carlo; Carn, Simon; Chiodini, Giovanni; Cottrell, Elizabeth; Burton, Mike (2019-10-31), "Carbon Dioxide Emissions from Subaerial Volcanic Regions", Deep Carbon, Cambridge University Press, pp. 188–236, ISBN 978-1-108-67795-0, retrieved 2020-09-10
- ^ a b Le Quéré, Corinne; Andrew, Robbie M.; Canadell, Josep G.; Sitch, Stephen; Korsbakken, Jan Ivar; Peters, Glen P.; Manning, Andrew C.; Boden, Thomas A.; Tans, Pieter P.; Houghton, Richard A.; Keeling, Ralph F. (2016-11-14). "Global Carbon Budget 2016". Earth System Science Data. 8 (2): 605–649. doi:10.5194/essd-8-605-2016. ISSN 1866-3516.
{{cite journal}}: CS1 maint: unflagged free DOI (link) - ^ a b Burton, Michael R.; Sawyer, Georgina M.; Granieri, Domenico (2013-12-31), "11. Deep Carbon Emissions from Volcanoes", Carbon in Earth, Berlin, Boston: De Gruyter, pp. 323–354, ISBN 978-1-5015-0831-8, retrieved 2020-09-10
- ^ Werner, Cynthia; Fischer, Tobias P.; Aiuppa, Alessandro; Edmonds, Marie; Cardellini, Carlo; Carn, Simon; Chiodini, Giovanni; Cottrell, Elizabeth; Burton, Mike (2019-10-31), "Carbon Dioxide Emissions from Subaerial Volcanic Regions", Deep Carbon, Cambridge University Press, pp. 188–236, ISBN 978-1-108-67795-0, retrieved 2020-09-10