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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 126 to 150 out of 308:

  1. ps Glaciers in sunny california are GROWING because of the extra moisture off the Pacific. I have posted links to all of these articles that describe what I have said. All of this climate change can easily be explained without super powerful CO2 forcing that historically does not seem to very powerful at all.
  2. Also you might want to read Peter Ward's work on the PT extinction (not the media coverage that assume CO2). While Ward does not recognize the importance of the Antarctic impact, he does cite the Siberian Traps that it created as releasing METHANE and poisionous gas. While the gas may have caused a GH condition, the GHG did not cause the extinction event, which (as he points out in Gorgon and elsewhere) was a two stage extinction. First the oceans died (90% of all ocean species) and was followed by land species (70%). What most forget when reading about the PT extinction is that the Pennsylvanian-Permian Ice Age had just closed and the planet had warmed (naturally) prior to the extinction event, just like right now after 12000 years of interglacial (the average length of an interglacial BTW).
  3. Here's the thing(s) about that: " Eastern Canada and the N.E. U,S, are not the only places on earth that have cooled while population centers warmed and it is from population centers that most data comes from. Why was this cooling ignored? " No, not really. The Arctic has warmed, the oceans have warmed (Aside from other data, sea level has been rising - that has to be mainly a combination of melting or temperature inceases - melting involves some of the heating occuring without temperature changes, of course). "South America, Antarctica and Africa have not experienced the same changes as Europe and PARTS of Asia. " ... " South Atlantic and Antarctic deep water is notably getting colder." The point being, you have to put all those together. It's still global warming, in the sense that there is more heat coming in then going back into space. "Glaciers in sunny california are GROWING because of the extra moisture off the Pacific." And why is that happening? "All of this climate change can easily be explained without super powerful CO2 forcing that historically does not seem to very powerful at all." It could be explained without CO2, but with strain and guessing. Much or most can be explained very very very very very very very very easily with a net forcing that is the sum of contributions from the changes in CO2, somewhat smaller from the rest of GHGs, a sizable likely negative aerosol contribution, rather small contributions from episodic volcanoes and solar radiation, and also, some other effects of ozone depletion (that doesn't explain the general global warming, etc, but it has effects). Etc.
  4. Sea level rise is within the Fairbridge curve; ie. normal or "expected". The Arctic is the obvious problem which is why I did not mention it. But outside of Greenland it won't cause a rise in sealevel because it is expanded (frozen) water that is also displacing sea water at present. Add to that the increased sea and glacial ice in Antarctica despite the small area near S.A. and there is no reason for additional sea level rise. The planet went through a brief warm spell, a large part caused by ocean cycles but some was abnormal. The anomally clearly shows which areas and they are decidely not global. I like the way you calculate out the CO2 forcing but I still agree with Spencer. There is a fundamental flaw somewhere. Be the one to find it.
  5. Regarding the P/T extinction: The concept as I understood it: There was a long ice-house period (with some significant ice, sometimes more (ice ages)) in the late Paleozoic. I've not been clear just when that ended, whether that was part of the P/T extinction or not. If it had ended but only just recently, that might have left species more vulnerable to any further warming. It was a time of continental collision - the formation of Pangea. One version: So then this Siberian trap flood volcanism starts up and persists for ~ a million years (more?), pumping CO2 into the air at a faster than typical rate. (Aerosols too, but those don't accumulate.) Eventually there is a lot more CO2. The Earth warms - maybe 5 degrees C - some extinctions occur (more on land??) The warmth causes CH4 release from the oceans. Sudden burst of warming. A total of 10 deg C more than before the flood volcanism? More extinctions. Oxygen doesn't dissolve as well in the oceans because of higher temperatures. Anaerobic bacteria that produce H2S become more commonplace. H2S in oceans, maybe some in the air. More extinctions.
  6. "the average length of an interglacial BTW" Average, perhaps. Not all. Once every few interglacials, one is longer - although this is too long of a pattern to have been repeated much in the last several hundred thousand years, but there was at least one extra-long interglacial. Based on astronomical forcings, this interglacial could be one of the extra-long ones, perhaps lasting another 20,000, 30,000, or 50,000 years, even without AGW. "t won't cause a rise in sealevel because it is expanded (frozen) water that is also displacing sea water at present. " Yes, of course. Yet, the sea level is rising; Greenland is losing land-based ice (potential point of confusion: the base of the ice is below sea level in many parts, and in Antarctica too (West Antarctica in particular), but the height of the surface of the ice is such that most of the weight of the ice is not supported by the water - it will raise sea level when it melts). Antarctica may also be losing ice in total even though some parts may be gaining ice mass. "Sea level rise is within the Fairbridge curve; ie. normal or "expected"." But if it is expected, what is the expectation based on? (Fairbridge's argument about Solar jerk was based on cycles dominated by Jupiter and Saturn, but the actual forces (tides on the sun) would be dominated by Jupiter and Venus, then Earth and Mercury, before any other gas giants - and I showed earlier these would be exceedingly exceedingly small effects.) I'm really not at all convinced that the Fairbridge curve was/is based on a solid body of evidence. "I like the way you calculate out the CO2 forcing" Thank you - but actually, I only explained how it is calculated, and the physical principles on which it is based, which are as sound as the inverse square law. "but I still agree with Spencer." Spencer doesn't really make a durable point, though.
  7. In that work of Spencer we've discussed, his argument was not abotu CO2 forcing but about climate sensitivity. There is no flaw in the fundamental sense. There is uncertainty. Spencer's argument seemed ill-concieved to me - the logic isn't quite there.
  8. Spencers argument is specifically about sensitivity to CO2. Look under Arguments, the Pacific Decadal Oscillation (at this site). I posted a link to a draft he did that they have refused to publish. I would prefer to be wrong about all this as I much prefer a warmer world but I fear that Spencer may be right. I am sure that Fairbridge was as the last two winters have been showing. The test is 2007 through 2011. Halfway there.
  9. ps This is spencers site. Articles and links to peer reviewed papers.
  10. Sorry, I missed something that you said. The Fairbridge curve and the Solar Jerk are two different hypotheses. The curve was rejected and is now accepted by the consensus while the solar jerk still has not been accepted. They are unrelated subjects.
  11. The problems I saw in Spencer's approach: 1. he was looking at climate sensitivity based on Temperature and radiative fluxes (top of atmosphere (TOA)) over rather short time periods. This is not an equilibrium climate sensitivity at all. (PS if a period of 5 years is sufficient, then why isn't 40 or 100 years of warming sufficient?) 2. conceivably there could be some net global cloud feedback, as well as the ice-albedo and and water vapor feedbacks and others, to forcing of climate from CO2, etc. Over short time periods (this is part of concern 1, actually), any water vapor feedback and other feedbacks, etc., would be limited by thermal inertia of the oceans. In addition, CO2 would generally only be a feedback over longer time periods. What is the cloud feedback to cloud forcing? 'Internal Radiative Forcing' is a feedback to some other internal effect, and will react to itself... 3. If one of the graphs could be shown in enough detail, one might judge to what extent temperature fluctuations are driving radiative fluctuations and vice-versa - obviously both happen - they must, that's the physics. 4. On that note, there can be some correlation, perhaps with some lag in time or not, between cloud radiative feedback and temperature, or temperature changes, that is not entirely due to a direct forcing of temperature by clouds OR a direct forcing of clouds by temperature. The short term variability may involve fluctuations in cloud type, amount, and distribution, and in temperature and wind, etc, that are of a different nature than that of longer term changes. 5. Spencer's description of how the IPCC, etc, estimate sensitivity is not descriptive enough for me to judge what it means. ------- FROM "And it appears that the reason why most climate models are instead VERY sensitive is due to the illusion of a sensitive climate system that can arise when one is not careful about the physical interpretation of how clouds operate in terms of cause and effect (forcing and feedback)." This seems to set aside any work that goes into trying to realistically model clouds based on observations of clouds and weather on smaller spatial scales (relative to global) - I think 'they' do that. " The allure of models is strong: they are clean, with well-defined equations and mathematical precision. Observations of the real climate system are dirty, incomplete, and prone to measurement error. " Well, I guess we should trust the models, then, eh Spencer? :) (I just found that particular passage to be very ironic, and not just within the context of this paper.)
  12. 3 and 4 in last comment - What I mean - Spencer refers to striations and spirals. Are those spirals predominantly clockwise or counterclockwise? (And does it vary by the size of the spiral? Etc...) It may be that the method for figuring out climate sensitivity that Spencer is criticizing is actually not a very good method, for perhaps some of the same reasons that Spencer's own method seems lacking. But this is just one piece of the puzzle (which might have been helpful but unnecessary? - There is a lot of other evidence out there). For example, Spencer mentions use of this method on climate models. But the most clear cut way to evaluate climate model sensitivity is to have multiple runs in response to various forcings and compare. ------------ "The curve was rejected and is now accepted by the consensus" Could you show me where it is accepted?
  13. It also occurs to me that Spencer's analysis could be capturing some aspect of the annual cycle.
  14. Patrick Wikipedia Entry Article A quick web search provides many more links.
  15. ps Here is another example from a different scientist. There is an apparent agreement with Fairbridge: Earth's Orbit Creates More Than A Leap Year: Orbital Behaviors Also Drive Climate Changes, Ice Ages ScienceDaily (Feb. 18, 2008) — The Earth's orbital behaviors are responsible for more than just presenting us with a leap year every four years. According to Michael E. Wysession, Ph.D., associate professor of earth and planetary sciences in Arts & Sciences at Washington University in St. Louis, parameters such as planetary gravitational attractions, the Earth's elliptical orbit around the sun and the degree of tilt of our planet's axis with respect to its path around the sun, have implications for climate change and the advent of ice ages.
  16. "Earth's Orbit Creates More Than A Leap Year: Orbital Behaviors Also Drive Climate Changes, Ice Ages ScienceDaily (Feb. 18, 2008)" That's just the Milankovitch cycles. It's basic grade-school science. Nothing new here. "There is an apparent agreement with Fairbridge" Well, according to "Article" from comment 139, Fairbridge was an early supporter of the Milankovitch cycle-driven climate changes concept. But that doesn't do anything to bolster his other concepts about solar jerk and sizable sudden sea level changes in the later Holocene. Also, "Article" did imply that the Fairbridge curve had been accepted in some way, but I don't buy that in full. Of course I wouldn't be surprised if sea level changes have some irregularity or even smaller cycles in them; there's no rule about having to rise completely monotonically (never reversing) between the peak of the last ice age and the present. But that's different then accepting the Fairbridge curve.
  17. Re: "That's just the Milankovitch cycles." Not Quite. It's a better understanding of various cycles, not just Milankovitch.
  18. Re: "It also occurs to me that Spencer's analysis could be capturing some aspect of the annual cycle." Climate is the average of annual cycles over a given time period. The 30 year limitation currently used skews the results.
  19. Re 143: 1. In the work of Spencer we had been discussing, he was using observations over short time periods - not long term climate trends - to attempt to infer the magnitude of climate sensitivity. Some portion of that short term variation occurs in under a year. Because of asymmetries between the hemispheres and also that fall and spring are not just the averages of winter and summer, etc, there will be some annual cycles in some global averages, which result from external forcing but of course involve feedbacks. Spencer also tried to explain most of recent global average surface temperature trends in terms of the PDO and ENSO, I think (it was a strain to do so - in other words, Occam's razor selects against this explanation). There may be an irony there - what positive feedbacks are available to boost internal variability while leaving external forcing so impotent? Of course, there are different spatial-temporal structures in different feedbacks to different things, etc... 2. The 30 year limitation - what limitation, exactly? The satellite data and some other data may only go back to x, but where it agrees with other data we might gain confidence in other data sets going back further; also we have paleoclimate and paleoclimate forcing records, and physics and modeling to fill in some of the blanks. Re 142: Where in the article did you see something besides Milankovitch cycles?
  20. Patrick "Re 142: Where in the article did you see something besides Milankovitch cycles?" Here: "According to Michael E. Wysession, Ph.D., associate professor of earth and planetary sciences in Arts & Sciences at Washington University in St. Louis, parameters such as planetary gravitational attractions," You see "planetary gravitational attractions" are an addition, referring to what I am talking about and not part of the Milankovitch cycle theory.
  21. Re: "Spencer also tried to explain most of recent global average surface temperature trends in terms of the PDO and ENSO," Yes, but he does not get into the cause of the PDO or ENSO as I have (granted it's only my hypothesis, it does lend support to it).
  22. "You see "planetary gravitational attractions" are an addition, referring to what I am talking about and not part of the Milankovitch cycle theory. " Those gravitational attractions are responsible for the Milanovitch cycles - precession of tilt and perihelion advance, changes in tilt, changes in eccentricity of orbit; also, changes in the plane of the ecliptic, though whether that has any significance climatologically is ... ? - but that's still a 70,000 year cycle. None of these cycles is shorter than ~ 20,000 years. If shorter-term astronomical cycles were meant to be implied to 1. exist (of course some do - but are there more than either of us is familiar with? The Chandler wobble (~over 400 days, no significant climatological consequence), cycles in the moon's orbit (perigee advance? (~between 8 and 9 years), precession of nodes (precession of tilt of the orbital plane relative to Earth's orbital plane) ~ between 18 and 19 years, some other shorter cycle(s) - these and consequent alignments with Earth-sun orbital geometry (including) perhelion/perigee alignment; solar cycles (of course they affect climate, but seem to only account for some fraction of recent warming, not-so-large a fraction especially in more recent decades) ... Of course, the Milankovitch cycles result from tidal torques on the Earth's equatorial bulge (mostly from the moon and sun) and tides acting on the Earth's orbit (the difference in the gravitational acceleration due to other planets acting on the Earth-moon system relative to the sun) - with some relativistic contributions, about which I don't know much. These are cummulative effects, I think, considering that the tidal torque on the equatorial bulge must go through semimonthly (no torque from moon when aligned with equatorial plane, which it crosses roughly twice in a full orbit) and semiannual cycles (no torque due to sun at equinoxes). There are obviously cycles in the alignments of the planets, and modulated by relative positions of perihelions and ascending nodes (the ascending node is where an object's orbit crosses a reference plane from south to north - typically the reference plane for planets is the ecliptic - approx. the plane of the Earth's orbit. One might also use the "invariable plane" of the solar system - the total angular momentum vector of the whole solar system is perpendicular to this plane). Anyway, Milankovitch cycles, I think, result over time as cummulative effects from forces that are also cycled over time over shorter periods. Are there significant cycling displacements in such things as tilt (magnitude and/or direction) and Earth-sun distance that occur in shorter time periods (that don't average to near zero over just a few years but can be set aside over thousands of years leaving the Milankovitch cycles)? If there were, I would have expected to here more about it in an article where "planetary gravitational attractions" were being highlighted. The impression I've gotten is that these short-term pulsations are small relative to the trend over 1000s of years. That is, using snow-depth as an analogy to tilt, eccentricity, etc, the impression I've gotten is that we get to ~ 1000 inches over 1000s of years by many small flurries that occur every month or so, a few bigger than the rest, but without much melt in between - as opposed to massive snowstorms followed by heatwaves.
  23. Patrick Re: 147 Fairbridge and his idea of Jupiter and other planets affecting the Barycenter, effecting solar activity, affecting climate. ps Remeber we discussed water levels before? I found this article (don't know how I missed it). World On Water "Geophysicists Show That Crust Temperature Variation Explains Half Of Elevation Differences In North America" February 1, 2008 — Geophysicists determined that tectonic mountain-building processes are not the only factor that determines elevation in North America. The temperature of the crust affects its density, and lower density crust will rise higher than colder, higher density crust. The heat in question comes from the Earthýs interior and also radioactive decay of various elements in the crust. Broadly, the Rocky Mountain region of the United States has the hottest crust, as well as the highest general elevation. Interesting no?
  24. This is where the volcanos are active in Antarctica Funny coincidence?
  25. Nice map. Are these all active right now? When was the last time they were active? Is the activity unusual for the last 1000+ years? "Geophysicists Show That Crust Temperature Variation Explains Half Of Elevation Differences In North America" Yes, that's interesting. If we were discussing changes over millions of years, it could potentially pertain.

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