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Do volcanoes emit more CO2 than humans?

What the science says...

Select a level... Basic Intermediate

Humans emit 100 times more CO2 than volcanoes.

Climate Myth...

Volcanoes emit more CO2 than humans

"Human additions of CO2 to the atmosphere must be taken into perspective.

Over the past 250 years, humans have added just one part of CO2 in 10,000 to the atmosphere. One volcanic cough can do this in a day." (Ian Plimer)

The solid Earth contains a huge quantity of carbon, far more than is present in the atmosphere or oceans.  Some of this carbon is slowly released from the rocks in the form of carbon dioxide, through vents at volcanoes and hot springs. Volcanic emissions are a small but important part of the global carbon cycle. Published reviews of the scientific literature by Mörner & Etiope (2002) and Kerrick (2001) report a range of emission of 65 to 319 million tonnes of CO2 per year. Counter claims that volcanoes, especially submarine volcanoes, produce vastly greater amounts of CO2 than these estimates are not supported by any papers published by the scientists who study the subject. 

The burning of fossil fuels and changes in land use results in the emission into the atmosphere of approximately 34 billion tonnes of carbon dioxide per year worldwide, according to the U.S. Energy Information Administration (EIA). The fossil fuels emissions numbers are about 100 times bigger than even the maximum estimated volcanic CO2 fluxes. Our understanding of volcanic discharges would have to be shown to be very mistaken before volcanic CO2 discharges could be considered anything but a bit player in contributing to the recent changes observed in the concentration of CO2 in the Earth's atmosphere.

Volcanoes can—and do—influence the global climate over time periods of a few years but this is achieved through the injection of sulfate aerosols into the high reaches of the atmosphere during the very large volcanic eruptions that occur sporadically each century. But that's another story...

Recommended further reading on CO2 and volcanoes can be found here: Terry Gerlach in Earth Magazine ; USGS

Last updated on 2 June 2017 by John Cook. View Archives

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Further reading

Tamino has posted two examinations of the "volcanoes emit more CO2 than humans" argument by looking at the impact of the 1991 Pinutabo eruption on CO2 levels and the impact of past super volcanoes on the CO2 record.

The Global Volcanism Program have a list of all volcanoes with a Volcanic Explosivity Index (VEI) greater than 4 over the past 10,000 years.

Myth Deconstruction

Related resource: Myth Deconstruction as animated GIF

MD Volcano

Please check the related blog post for background information about this graphics resource.


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Comments 151 to 175 out of 237:

  1. Patrick It has been determined that the earth does not work slowly but just like evolution, in fits and spurts, ie. it does not matter if it's a million years or a hundred years. What matters is current phase which is an active phase. This was noted in an article this past year (more new information not taken into account by the IPCC). Yes, those volcanos are active. And those are only the ones that are under the ice, not the ones on the ocean floor. It's a subduction zone.
  2. ps We are also looking at overall trends, over millions of years in addition to the current phase. It certainly does pertain.
  3. Patrick Here is a couple more new items of increased tectonic activity: New Fault Raises Threat of Eastern Earthquakes Yellowstone Earthquake Swarm Puzzles Scientists
  4. "ps We are also looking at overall trends, over millions of years in addition to the current phase. It certainly does pertain. " To the subject of climate in general, but not so much to AGW specifically in as far as the causes of recent changes (last 100 years, especially last few decades) must be, outside of natural variability contributions, things which have recently changed and in so doing reached states unseen for some longer time. "What matters is current phase which is an active phase. This was noted in an article this past year " Which article? "Yes, those volcanos are active. And those are only the ones that are under the ice, not the ones on the ocean floor. It's a subduction zone. " But are they unusually active? The numbers just don't add up to explain much of recent climate changes, if even to suggest some significant multidecadal trend in tectonic activity.
  5. Patrick I am referring back to the articles posted above in this thread. Yes the activity increased in the late 1970s and has continued. That is exactly what all of the above links indicate. And what is usual? The realization that tectonic activity is not a constant is a recent realization (the article on this concerns mountain building in fits and spurts). So how can it be more than usual, as there is apparently no usual.
  6. ps The "new" fault is obviously not new, it just has become active again. I knew it was there, so obviously they should know at LEAST what I was able to learn. It's a very sad state of affairs for the educational system in the U.S.
  7. "The "new" fault is obviously not new, it just has become active again. I knew it was there, so obviously " Are you sure the fault you knew about is the specific one they described as recently discovered? I didn't get the impression from the article that there has been any recent activity at that specific fault (where I heard about it from a different source, my impression was that the bubbling liquefied sand was not an ongoing process but something that had happenned and left a mark in the geologic record, which helped identify the fault), which is near but not the same as the New Madrid fault, which I also already knew about. "So how can it be more than usual, as there is apparently no usual." Of course it is not constant, but as with climate and weather, there will be a general state of tectonic activity within which variations and events occur on smaller time scales. There does seem to me to be more tectonic activity right now than 10 years ago (but is that a false impression created by a very small data set? - in other words, this isn't something I've followed closely). Is this level unusual for the last 100 years? The last 1000? There was an earthquake in Portugal - I think during the little ice age, actually (but I'm not sure) - and it killed something like over 70,000 people. Which is a great tragedy, of course, but what does that imply in as far as tectonic trends or short term tectonic activity - climate relationships? Not much. When you picture the level of tectonic activity over time - let's say the last 1000 years - what do you picture: (_ low, , - medium, | high, ^ higher, A highest) (graphs coming soon)
  8. A. -^^__A|__^||^^|^|__||A|_^-A^^^A-A|A-_^-^-_|^---_-A-|A^^_|A_A_^^^A-AA^^^_-_A-^-_||__--A-_^-^A_||-__^_--_|A-^^_|- B. A----A-|A-^|AA^--|A___-|^-A_|_||-|-|^-_^___-_A|_-^^A_-_^AAA_A|^A_^|A_^__-AA_A-__|A|A^^A^^A-_||___^^|__-A^AA^-A- C. _|_^^^AAA^_|-__-_|^A|----A^|^_|A-^__|___|_|___A^_AA|_---_-^|--_____A|_|^A--^|_-^A_|A-|-|-__A__A-_^A-_|^-|^^-^A_ D. __^__^-|^--_AA_^__A____^-||_^||__A__^-_--_-_^_-_-____|-_-||_-A__A__|__^__A^-____||-_|_A_|_____|-___A|-__^___^__ E. __^____^A____--_|-^--|__-__|A-|^-_|A__-||_A__-A^^-__|-|___|___|_---_^^__|A-^-A__-^-_-__A-_^____|___|__^|_______ F. ___^___--__|-_-_|__|____|___-_-|____|__^-____||_-__-_-|-_-__^____|_-____|_|___--__|-__^_^|^____|___|-_-_-|-_-_| G. --|-____-___-A-^__-|---_-__-_A____-_-__--A__---_-__|-|-_|-_A-|_|_|_-_^|_A--_-^^^_-_-_^___-__^--___|___|_|_|____ H. _____A_--A|__-_^-_-A_^_-_-___--_|_|__----|__--_^A-^---_-|-A____|__---___---__|^___^___|-_____A_-|_^_-|______^|_ I. -_-__--A|__|-_^^------__|-^-_---__-|__-|__-_|-_-____-_|_^-_-___|_|-__^___A___-||A-|-A_______^__^-__-_-^___A_|_^ J. _-_A|-_-|---_|^--__---^_---|-__-_A_-_|^-_A-__^-__|-^_-__-_||_^-_-|____-____-_--^|__|_--_--^__-__-|_--|^-A^A-|^A^
  9. Patrick I have been assuming that you are up on geology since you are studying climate. Your recent comments have indicated that I made a false assumption. I am sorry if I have confused you. On the antarctic: The penninsula of west antarctica sits on a subduction zone, that is the reason that the volcanos are active and mountain building is still occurring in that region. That is the southernmost extent of what they call "the ring of fire". The New Madrid area is a juncture of a fault line and a fracture zone. In each of these areas there is only one main fault but it has fractures running perpendicular and minor faults running parallel. The appalachian chain follows the main fault. It has many inactive volcanos all along it from Texas to Maine as proof. They are "discovering" old faults that were considered "dead" but they were simply not very active, and that activity has been increasing for about 25 to 30 years now all along that main fault. Another area of subduction is the northern edhe of Greenland and Arctic Canada. Again this area has only recently increased in activity. The subduction zones along Asia and Alaska have also increased activity, the recent volcanic activity is simply indicative of the tectonic activity. This is why geologists make good climatologists.
  10. PS don't think too hard about it. All except J are just random sequences (I used a spreadsheet to make the text strings). (Not that there aren't such things as random trends.) The first few follow power laws; the last few have each level about half as likely as the next highest. Anyway, even with some correlation between tectonics and climate, one still has to show at least either that the correlation is robust (reoccurs with statistical significance) and/or that there is some reason to expect a predictable (as opposed to butterfly effects) causal relationship. At least that is met for short term volcanic aerosol cooling, for longer term geologic influences on atmospheric CO2 concentration, and changing geography (but a local land rise of 5 inches isn't generally significant as a regional or global climate cause).
  11. PS 160 follows 158, not comment 159 "This is why geologists make good climatologists." What "This"? - for comment 159 is essentially all about geology. Why not then assume that because I have a grasp of climatology, I might then know more about geology than you do - that would also potentially be erroneous. Yes a fault, volcano, etc., might be thought dead/extinct and later discovered to still be active or have potential for activity in the not too distant future, etc. But that doesn't mean that all new discoveries of potentially active faults had already been identified as faults, does it? An example of what I am aware of - The New Madrid seismic zone is a leftover of a failed rift - an aulacogen (aka Mississippi Embayment ?) - from around the time of the breakup of Pangea or around that time (I'm better at the generalities than the exact dates). A much older example of a failed rift underlies Lake Superior and is ~ a billion years old or so - at least roughly in the same temporal territory as the Grenville orogeny (might they be causally linked?).
  12. "that you are up on geology" Well I guess that depends on what you mean by 'up on'. I have a good basic understanding of the rock cycle, plate tectonics, mantle convection, some stuff about the core, geochemistry, how material is processed so as to concentrate some materials in some places in some forms (repeated partial melting and freezing for igneous rocks), crystal lattices, the large scale of geologic history; I could draw a rough map of Pangea; am less clear on Rodinia, I've heard of Mazatzal (spelling?); I know detrital pyrite is an indicator of lack of oxygen; ... But no, there are certainly a lot of minerals (especially the rare ones) that I couldn't identify or have never heard of, I don't know every division of time, I don't know every minor fault, I don't know precisely where the line is drawn between active, dormant, and extinct; I have some more detailed knowledge about a few things, like Baraboo quartzite (it goes back ~ 1.8 billion years, has some association with the Penokean orogeny; color an indication of presence of atmospheric oxygen at the time).
  13. Patrick No offense meant. I did assume that you understood more geology than I do. Your questioning if volcanos are active over an active subduction zone threw me a curve. I assumed that you knew where the subduction zones were (Hansen et. al. apparently doesn't). The pattern of activity has been increasing since the 1970s. Looking at paleomaps, it is clear that the "canadian shield" is not a solid plate. The rifting really is not a failed rift. What we have is a compression along an old plate edge that we assumed to have fused when beringia was formed. I don't believe anything "fused" is actually a permanent condition. PS I don't understand what 158 represents.
  14. ps To clarify, does J indicate the current time and what time frame are you depicting?
  15. pps To see what I mean look at this map: Look at New England and Nova Scotia near the bottom left of the map.
  16. Re 165 - yes, I know ultimately every sizable chunk of continent came together from smaller terranes. Of course the Keweenawan rift likely cut through some older boundaries and may well have incorporated some older boundaries. But it was itself a rift. Although it is also true that it absorbed some compression at a later time (but not much later?)- formerly fallen blocks were forced back up. "I don't believe anything "fused" is actually a permanent condition" - well, that makes sense, but I would guess that, other things being equal, forces would be more likely to reactivate more recently active faults than faults that have been dead for longer. Re 164 - each is a hypothetical ~1000 year 'graph' of tectonic activity. I altered J in an attempt to show what one might expect it to look like if recent global warming were driven by an increase in tectonic activity. Even if it did look that way, however, there is still the problem that there is not enough reason to expect one to cause the other. Whereas there is much reason to expect adding CO2 to the atmosphere to cause warming, with or without paleoclimatic and geologic record correlations, though every bit can help clarify matters. I don't see what your point is about the map (458 Ma). The Keweenawan rift (underlying Lake Superior but extending elsewhere) predates this map and within the borders of the portions (or at least mostly so) of North America so far assembled and still together at 458 Ma.
  17. Patrick I was referring to New England and Nova Scotia being on a seperate plate. It's actually more than New England but that's irrelavent. The joining of this land mass from the bottom left to the canadian shield is responsible for much mountain building and the primary appalachian fault which is still active. They just had a 3.0 quake in Morristown N.J. a couple days ago - extremely rare event for N.J. which I am assuming occurred along the Ramapo fault (a parallel fault). This makes sense when you realize that the arctic ridge increased speed and is pushing the canadian shield south again.
  18. "I was referring to New England and Nova Scotia being on a seperate plate. It's actually more than New England but that's irrelavent. The joining of this land mass from the bottom left to the canadian shield is responsible for much mountain building and the primary appalachian fault which is still active. " - Okay... aside from there being one fault that can be designated the primary fault, I was aware of that. Isn't possible, though, that there has been no increase in activity? Because: "They just had a 3.0 quake in Morristown N.J. a couple days ago - extremely rare event for N.J." (PS I heard about that one. I had known about the New Madrid fault quite some time ago but just a couple or so years ago I was surprised to see on a map that there was significant seismic hazard in South Carolina and elsewhere in eastern North America. I think there've even been a few big earthquakes in the New York/eastern Canada region (historical).) When events are so rare, it is really hard to tell from a short record just what would signify a trend in activity. Maybe there's an average of one >= 3.0 earthquake in NJ every 500 years or so (pure hypothetical example - I don't know what the number actually is). You did refer to news about scientific findings from the Arctic ridge, but it was never established that there was an actual significant increase in speed. Mantle convection and the large scale plate motions that follow it are gradual on the scale of many years to many hundreds of thousands of years ... not sure where the long cut-off would be - the point being that, as some portion of the stress is relieved in jolts, I would expect the finer time scale will show some irregularity in motion on the spatial scale of the stress build up and relief by single or a few earthquakes. But this will tend to average out on intermediate timescales because the source of such stress is from the pressure variations due to elevation, composition, and temperature variation, which change significantly only on much longer timescales.
  19. Yes, the fault that follows the Hudson river had a 5+ back in the 70s near Bear Mountain. I remember that one because I felt it in N.J. over a hundred miles away and there was concern about the epicenter being close to a nuclear power plant. I was born and raised in N.Y. and raised my children in N.J. so I am familiar with the area. Never even heard of earthquakes there until the 70s. Knew about the 2nd avenue fault from history, they discovered it blasting for a subway. Obviuosly they stopped work on it.
  20. ps thats 2nc Avenue in Manhatten (NYC).
  21. I forgot the "booming" noises (enough to rattle windows in north western NJ) that were in all the NJ papers in the 70s. It took them a while to realize that they were earthquakes because no one alive at the time had ever felt them in NJ. They thought the Ramapo fault was dead and that's the main one through NJ.
  22. "Obviuosly they stopped work on it. " Was that before or after they realized the fault had a potential for activity? PS - a little fuzzy on some of this, but I think: The Keweenaw rift formed (as a rift) just before 1000 Ma, and this may coincide with the Grenville orogeny (to the east if oriented as now) - (perhaps the rift occured over a descending slab of subducted oceanic crust, from the subduction zone to the east (if oriented as now)). Shortly afterward, it reversed from being extensional to being compressional; fallen blocks (The Saint Croix horst?) (having been covered with basalt and sediment) were forced back up again. This occured between 1000 Ma and 900 Ma, during another collision (I believe distinct from and coming after the Grenville orogeny, though not completely sure). But, faults were again reactivated during another collision in the Ordivician, with the former rift absorbing a bit more compression.
  23. Patrick "Obviuosly they stopped work on it. " Was that before or after they realized the fault had a potential for activity? The blasting caused an earthquake. Not a good thing under downtown NYC. :)
  24. The Keweenaw rift That sounds logical enough. I thought that you were talking about a recent event when you first said "a failed rift". It does not seem to have failed, just old and later compressed. My cousin has a degree in geology (not a PhD) and showed me some of the features upstate New York some years ago. Where he is now (near Albany) has Devonian rock all over, covered with fossils. Interesting stuff.
  25. Volcanic Eruptions Greater than 4.0 Period from 1945 to 1970 (16 major eruptions) Nomen Year Rank Location FERNANDINA 1968 4 Galapagos AWU 1966 4 Sangihe Islands KELUT 1966 4 Java TAAL 1965 4 Luzon SHIVELUCH 1964 4+ Kamchatka AGUNG 1963 5 Lesser Sundas AGUNG 1963 4 Lesser Sundas BEZYMIANNY 1956 5 Kamchatka CARRAN 1955 4 Chile SPURR 1953 4 Alaska BAGANA 1952 4 Bougainville Island KELUT 1951 4 Java LAMINGTON 1951 4 New Guinea AMBRYM 1951 4+ Vanuatu HEKLA 1947 4 Iceland SARYCHEV 1946 4 Kuril Islands Period from 1971 to 2006 (26 major eruptions) Nomen Year Rank Location RABAUL 2006 4 New Britain MANAM 2005 4 N.E.of New Guinea REVENTADOR 2002 4 Ecuador RUANG 2002 4 Sangihe Islands SHIVELUCH 2001 4 Kamchatka ULAWUN 2000 4 New Britain RABAUL 1994 4 New Britain LASCAR 1993 4 Chile SPURR 1992 4 Alaska HUDSON 1991 5+ Chile PINATUBO 1991 6 Luzon KLIUCHEVSKOI 1990 4 Kamchatka KELUT 1990 4 Java AUGUSTINE 1986 4 Alaska CHIKURACHKI 1986 4 Kuril Islands COLO 1983 4 Sulawesi GALUNGGUNG 1982 4 Java CHICHON 1982 5 Mexico CHICHON 1982 4+ Mexico PAGAN 1981 4 Marianas ALAID 1981 4 Kuril Islands ST.HELENS 1980 5 Washington AUGUSTINE 1976 4 Alaska TOLBACHIK 1975 4+ Kamchatka FUEGO 1974 4 Guatemala TIATIA 1973 4 Kuril Islands Source: Results: 10 more eruptions recently with a VEI >=4 than for the same length preceeding period using 1970 as a cutoff. Note: I have no access to the additional activity or the undersea volcanos that are not included.

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