It seems there’s really no complete measurements on how much CO2 is coming out of volcanoes, both active and inactive.
From Livescience: Long Invisible, Research Shows Volcanic CO2 Levels Are Staggering (Op-Ed)
…
In 1992, it was thought that volcanic degassing released something like 100 million tons of CO2 each year. Around the turn of the millennium, this figure was getting closer to 200. The most recent estimate, released this February, comes from a team led by Mike Burton, of the Italian National Institute of Geophysics and Volcanology – and it’s just shy of 600 million tons. It caps a staggering trend: A six-fold increase in just two decades.
These inflating figures, I hasten to add, don’t mean that our planet is suddenly venting more CO2.
Humanity certainly is; but any changes to the volcanic background level would occur over generations, not years. The rise we’re seeing now, therefore, must have been there all along: As scientific progress is widening our perspective, the daunting outline of how little we really know about volcanoes is beginning to loom large.
Quiet monsters
The exhalations of our planet can be spectacularly obvious. The fireworks, though, are only part of the picture. We now know that the CO2 released during volcanic eruptions is almost insignificant compared with what happens after the camera crews get bored. The emissions that really matter are concealed. The silent, silvery plumes which are currently winding their way skyward above the 150 or so active volcanoes on our planet also carry with them the bulk of its carbon dioxide. Their coughing fits might catch the eye — but in between tantrums, the steady breathing of volcanoes quietly sheds upwards of a quarter of a billion tons of CO2 every year.
We think. Scientists’ best estimates, however, are based on an assumption. It might surprise you to learn that, well into the new century, of the 150 smokers I mentioned, almost 80 percent are still as mysterious, in terms of the quantity of CO2 they emit, as they were a generation ago: We’ve only actually measured 33.
If the 117 unsampled peaks follow a similar trend, then the research community’s current projection might stand. But looking through such a small window, there’s no way of knowing if what we have seen until now is typical or not. It’s like shining a light on a darkened globe: randomly, you might hit Australia, and think you’d seen it all – while on the edge of your beam, unnoticed, would be Asia. Our planet’s isolated volcanic frontiers could easily be hiding a monster or two; and with a bit of exploration, our estimate of volcanic CO2 output could rise even higher.
You’d think that would be enough. That might be my fault — I tend to save the weird stuff until the end. Recently, an enigmatic source of volcanic carbon has come to light that isn’t involved with lava — or even craters. It now seems that not only is there CO2 we can’t get to, there’s some we can’t even see.
…
Even more incredibly, it even seems that some volcanoes which are considered inactive, in terms of their potential to ooze new land, can still make some serious additions to the atmosphere through diffuse CO2 release. Residual magma beneath dormant craters, though it might never reach the surface, can still ‘erupt’ gases from a distance. Amazingly, from what little scientists have measured, it looks like this process might give off as much as half the CO2 put out by fully active volcanoes.
If these additional ‘carbon-active’ volcanoes are included, the number of degassing peaks skyrockets to more than 500. Of which we’ve measured a grand total of nine percent. You can probably fill it in by now — we need to climb more mountains.
Related articles
- Long Invisible, Research Shows Volcanic CO2 Levels Are Staggering (Op-Ed) (livescience.com)
- Indonesia’s Mount Sinabung continues to erupt (abc.net.au)
- Volcano spews ash 3km high (stuff.co.nz)
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I have no expertise here, but if I were tasked with estimating natural CO2 emissions, I would want to know the rate of carbonate subduction at the continental margins, thinking this might approximate CO2 emissions from gassy volcanos. I would largely discount volcanos along seafloor spreading zones; these would be basaltic.
Jquip says:
November 16, 2013 at 2:49 pm
Any one have info on how this would effect, or not effect, isotope ratios for c12 and c13? That is, is this just a complete boff of how much is being produced, or are there knock-on effects for source assignment?
Depends where the magma is coming from:
– subduction volcanoes (like these in Indonesia and Italy) emit CO2 from the calcite deposits at the ocean floor which in general are around zero per mil δ13C. See e.g.:
http://link.springer.com/article/10.1007/s00445-010-0423-2?no-access=true
– deep magma volcanoes (like the Icelandic ones) emit CO2 from the deep earth and are in general lower in δ13C, somewhere between -4 and -7 per mil δ13Cl.
– the atmosphere currently is at -8 per mil δ13C
– human emissions are around -24 per mil δ13C
That means that, with a few exceptions, all volcanic vents emit CO2 that would increase the 13C/12C ratio in the atmosphere. See e.g.:
Italy:
http://www.springerimages.com/Images/Geosciences/1-10.1007_s00445-010-0423-2-2
http://www.earth-prints.org/handle/2122/4383
Mount Reinier:
http://igitur-archive.library.uu.nl/dissertations/2004-0128-122010/c6.pdf
and many more…
Myrrh says:
November 16, 2013 at 7:00 pm
From the geologist (also referenced by Janama):
Both tectonic and volcanic CO2 are magmatic and depleted in both 13C & 14C
Depleted in 13C against subduction volcanoes, but enriched compared to the atmospheric ratio.
Quite strange that a geologist doensn’t know that…
Thus whatever the amount of CO2 emitted by volcanoes, that can’t be responsible for the steady decrease in δ13C over the past 160 years:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/sponges.gif
Further: most of the CO2 emissions from underwater volcanoes will simply dissolve in the deep oceans and stay there for extremely long periods. The deep ocean δ13C is around zero per mil…
See further:
http://www.agu.org/pubs/pdf/2011EO240001.pdf
@Willis
Willis Eschenbach says:
November 16, 2013 at 2:43 pm
According to the article, the current best estimate is that volcanoes put out about 600 megatonnes of CO2 per year, which is 0.6 gigatonnes (0.6E+9 tonnes).
Human activities, on the other hand, annually release on the order of 33 gigatonnes of CO2 …
That means that if the volcanoes are actually putting out twice the best estimate, which they may be doing, it would still only be about 4% of human emissions.
I had looked up the human emissions and seen the discrepancy. So I wondered how accurate the human emissions figure was.
It wouldn’t be the first time that Climate Scientists had exaggerated data by orders of magnitude…
Dodgy Geezer says:
November 17, 2013 at 3:57 am
I had looked up the human emissions and seen the discrepancy. So I wondered how accurate the human emissions figure was.
Human emissions are calculated from fossil fuel sales (taxes!) and fuel burning efficiency. Probably more underestimated than overestimated because of under the counter sales…
Ferdinand Engelbeen says:
November 17, 2013 at 4:32 am”
Estimated. Most likely OVER-ESTIMATED due to the fact that (In Australia at least) CO2-e is calculted as 3.76 times the effect 1 tonne of CO2 has on climate (Which is bogus anyway).
This is interesting, but, as Steve Keohane notes, 0.6 Gt CO2 per year is still very small compared to other CO2 sources and sinks.
CO2 is 27.3% carbon and 72.7% oxygen, so 0.6 Gt CO2 is only 0.164 GtC (gigatons carbon). For comparison, AR4 estimates that anthropogenic sources contribute about 7 GtC/yr, and natural sources are about 25x that. That would make the volcanic contribution about 0.1% of the total.
Whoops, I see that Willis did essentially the same calculation that Steve and I did, first.
It’s fun having all the “volcano alarmists” plus Willis plus Nick in one thread. My question to the the former is: are volcanoes seasonal? Or put another way: what causes the large annual wiggle? It is larger in the NH than in Antarctica, so the explanation must include that fact. Also the annual wiggle measurement was repeated worldwide for decades, so it is not a Keeling invention.
Second,the observed decrease in pH in the ocean, e.g. http://www.webpages.uidaho.edu/envs501/downloads/Wei%20et%20al.%202009.pdf would have to correspond to a very large secular increase in undersea volcanoes in the 20th century. AFAICS, there is no documented evidence of such an increase in undersea volcanoes unless this blog post is evidence. But so far there are other explanations for rise in estimates.
Pat says:
November 17, 2013 at 4:53 am
Estimated. Most likely OVER-ESTIMATED due to the fact that (In Australia at least) CO2-e is calculted as 3.76 times the effect 1 tonne of CO2 has on climate (Which is bogus anyway).
Nothing to do with the effect of CO2 on the climate. Fossil fuel sales are known from taxes on the sales. Burning coal, oil and gas gives specific amounts of CO2, thus the amounts of CO2 from burning fuels is known, within the limits of the sales and burning efficiency. But as humans are pretty smart in avoiding taxes, the CO2 emissions are probably underestimated…
http://cdiac.ornl.gov/trends/emis/aus.html
What? You want to collect more data? That really shouldn’t be necessary. We can just krige it, or find some other statistical analysis, or, I KNOW, we can MODEL it! Those are a lot easier and cheaper than having to trek out to some God-foresaken place and do actual science.
Thanks, Anthony. Good reporting.
I think that natural CO2 dominates, not “man-made” CO2. Moreover, H2O dominates, not CO2.
We live in a natural world, not a man-made world.
As long as undersea volcanoes are venting below the carbonate compensation depth, it doesn’t matter how large their co2 flux is. It simply falls out of the equation.
More climate science, this time using the Mann-Trenberth & Jones-Hansen-Schmidt transform functions. Assume 150 under air volcanoes (although a trivial few were under water) @ur momisugly mean annual CO2 production of 4 MT times 3.5 million undersea volcanoes, yields 14,000 GT of CO2 per annum, ignoring as trivial the 150 under air volcanoes. OK, assume only 100,000 of the undersea volcanoes are comparable to the 150 land volcanoes & ignore the CO2 contribution of the other 3.4 million calculated under water volcanoes & from the 150 under air volcanoes. That gives us only 400 GT per year. Make it 10,000 undersea volcanoes comparable to the 150 based upon a sample of 33 & it’s 40 GT, again without the land contribution.
I’m not sure I understand your math here. If we assume the 150 land-based volcanoes are the only significant emitters, and that the density of significant emitters is proportional to area, then the land-based numbers — whatever they are — should be multiplied by 3.33 (to go from 30% of the total surface to 100%). So if you assert 600 Mt/year for the land, you should end up with 2 Gt/year for the entire surface. To assert anything else, you have to have measurements that I don’t think that we have — some very concrete reason to think that there are more significant emitters per square kilometer underwater compared to on land. Maybe there is, I don’t know, but asserting that there are 150 important (enough) land volcanoes and 3.4 million equally active underwater volcanoes seems dubious. Yes, I know about oceanic rifts and subduction zones and all that, but still, you’re basically asserting that e.g. the mid-atlantic rift is an oozing line of naked magma. Perhaps it is, but I’d think one would need to perform a whole lot of active measurements to verify its CO_2 contribution, not simply try to scale a land-based contribution from volcanoes of a completely different structure.
However I do agree with you that assuming a simple factor of 2 is insufficient. If we assume maximum ignorance, the correct multiplier is 3.33. If we have some sound Bayesian prior, there might be a good reason to increase or decrease this factor, but I’d feel a lot more comfortable basing the estimate on direct measurements in situ instead of scaling measurements that the top article itself is dedicated to asserting are not particularly reliable, yet. “The uncertainty in the volcanic contribution is large” is perhaps the best conclusion from the article, and it could easily be large enough to completely screw up e.g. the Bern model.
A question — it was asserted that there (could? do?) exist stable pools of liquid CO_2 in the deep ocean. This suggests that there is some ocean depth where liquid CO_2 formation is favored. This in turn suggests that there could actually be liquid CO_2 rain in the deep ocean, places where saturated CO_2 falls out of the surrounding water as droplets. This, in turn, would be a serious alteration to the Bern model, as it could put a cap on the CO_2 concentration of the deep ocean at saturation, after which it falls out as rain, nearly stably sequestered.
What is the observational evidence for any or all of this? Are there measaured/observed pools of liquid CO_2, and are those pools thermodynamically stable or slowly evaporating? How close is the deep ocean to saturation (or at what depth does it become saturated and hence unstable to CO_2 rain)?
rgb
J Martin says:
November 17, 2013 at 2:49 am
Sorry, J, but that’s not true in the slightest. There was no “increased volcanic activity during the Little Ice Age”, that’s an urban legend. See my post here for a graph of volcanic activity versus time. There is nothing like what you claim.
w.
Pat says:
November 17, 2013 at 4:53 am
Citation? As far as I know, Australia’s emissions are figured out just like the rest of the planet …
w.
Hoser says:
October 20, 2013 at 11:26 pm
Glad we are getting around to this topic.
eric1skeptic says:
November 17, 2013 at 5:55 am
The annual “wiggle” in the atmospheric CO2 is generally said to come from the change in the amount of actively growing plants, particularly in the Northern Hemisphere. In the summer they absorb CO2, and in the winter they release it. As a result, CO2 peaks in May and is at its smallest in October.
w.
It may be important to consider natural CH4 -> CO2 as well. It is not clear whether the measurements of CH4 production and mapped sources of natural CH4 emissions are sufficiently accurate. Etiope, et al., have estimated geological and wetland emissions of CH4 are about 6 million tons per year in Europe. Could the value be extrapolated to the world? Do we know enough? Is the sea floor also a “wetland” and a major source of methane? Is methane trapped below a certain depth and consequently, can most of the sea bed can be ignored? Or even there, do methanotrophs consume methane directly or in clathrates, releasing CO2?
ftp://ftp.eol.ucar.edu/pub/temp/users/campos/2012dc3/papers/etiope.atmosEnv2009.natural.ch4.geo.seepage.europe.1-s2.0-S1352231008002483-main.pdf
http://escholarship.org/uc/item/01k4m30p#page-1
The EPA say this However, the U.S. Geological Survey (USGS) reports that human activities now emit more than 135 times as much CO2 as volcanoes each year.
http://www.epa.gov/climatechange/science/causes.html
The annual “wiggle” in the atmospheric CO2 is generally said to come from the change in the amount of actively growing plants, particularly in the Northern Hemisphere. In the summer they absorb CO2, and in the winter they release it. As a result, CO2 peaks in May and is at its smallest in October.
It’s not a thermal variation? I would have expected it to follow the seasonal variation in GAST, or rather global SST as temperature rise/fall affects surface absorption/emission rates (or for that matter phytoplankton consumption rates) as a larger effect. I stand corrected.
rgb
We now know that the CO2 released during volcanic eruptions is almost insignificant compared with what happens after the camera crews get bored. The emissions that really matter are concealed. The silent, silvery plumes which are currently winding their way skyward above the 150 or so active volcanoes on our planet also carry with them the bulk of its carbon dioxide. Their coughing fits might catch the eye […] It might surprise you to learn that, well into the new century, of the 150 smokers I mentioned, almost 80 percent are still as mysterious, in terms of the quantity of CO2 they emit, as they were a generation ago: We’ve only actually measured 33.
Haha, I had to read that a few times and follow the link to the picture before I realised the article wasn’t attempting to link the rise in CO2 to cigarette smokers! I even checked for a “satire” tag!
I know. What a numpty.
Robert Brown says:
November 17, 2013 at 8:37 am
I wasn’t actually asserting anything. It was meant as a wildly hypothetical joke, to show what volcanic CO2 might be, since in fact science knows essentially nothing about the degree of underwater emission.
I assumed without evidence (hence the similarity to feedback assumptions in GIGO GCMs) that oceanic crust, being so much thinner than continental & of different composition, would emit more rather than less CO2. I picked twice as much out of thin air, as a possibility that can’t be ruled out in the present state of our lack of knowledge. So if underair & lake volcanoes produce, let’s say, 1 GT, then the oceans could produce {71/29 (oceans cover 71% of the planet, not 67, of which some of course is continental shelf) X 1 GT} = 2.45 GT, for a total of 3.45 GT for land & sea. However, applying my assumption of twice as much emission from the oceans yields (2.45 X 2) = 4.9 sea + 1.0 land = 5.59 GT. If I raise my land assumption to 2 GT & maintain the presumed double for ocean emission rate, then the total would be 11.18. I rounded off in my prior calculations & assumed simple 2:1 sea:land ratio, since it involves such WAG assumptions anyway.
CO2 emission needn’t occur only with magma lava flows, which fact is yet another source of great uncertainty in estimating volcanic contribution. Even on land, science doesn’t know how much CO2 leaks out of the ground in the vicinity of active & geologically dead volcanoes. IMO whatever the figure might be, it’s liable to be greater in the oceans, where new seafloor is constantly being produced at ridges & where so many giant volcanoes, only now being recognized, exist, thanks perhaps to the thinness of crust there & consequent ease with which smaller impacting bolides (space rocks) can punch through the crust to the mantle, creating hot spots such as that which has made the Hawaiian Islands & Emperor Seamounts.
You raise good questions about CO2 saturation in the cold, dense depths. I don’t know.
Tonyb says:
November 16, 2013 at 3:19 pm
David ball
A couple of years ago I was told by a Cambridge university volcanologist that it was believed that there are ten thousand times more underwater volcanoes than previously believed. I have no way of determining if this is accurate.
Tonyb
http://www.newscientist.com/article/dn12218#.Uokpa7OYO90
“The true extent to which the ocean bed is dotted with volcanoes has been revealed by researchers who have counted 201,055 underwater cones. This is over 10 times more than have been found before.
The team estimates that in total there could be about 3 million submarine volcanoes, 39,000 of which rise more than 1000 metres over the sea bed”
I understand the seafloor being much thinner then the continental crust, I would not be surprised if more then 90% of the volcanic activity would happen under the sea.
rgbatduke says:
November 17, 2013 at 11:07 am
It’s not a thermal variation? I would have expected it to follow the seasonal variation in GAST, or rather global SST as temperature rise/fall affects surface absorption/emission rates (or for that matter phytoplankton consumption rates) as a larger effect. I stand corrected.
The seasonal T-CO2 fluxes are countercurrent for oceans as for vegetation (land as well as ocean). In the SH, the fluxes are near in equilibrium (very small seasonal variation), but in the NH, (land) plants win the battle, as can be deduced from the opposite CO2 and 13C/12C ratio changes over the months.
Monthly data can be downloaded from the CDIA website for the same site for both CO2 and δ13C:
http://cdiac.ornl.gov/trends/co2/iso-sio/graphics/iso-graphics.html
or from NOAA:
http://www.esrl.noaa.gov/gmd/dv/iadv/
Thanks Willis, rgbatduke, and Ferdinand for the answers about the seasonal wiggle. RGB, I too thought there was a thermal component since the earth is closest to the sun in January and the SH ocean warming would lag that by a few months in line with the peak in CO2.
This is “WebHubTelescope’s plot of SST and CO2: http://img836.imageshack.us/img836/1332/co2withphaseshift.gif from this thread: http://judithcurry.com/2012/03/15/on-the-adjustments-to-the-hadsst3-data-set-2/ It does not appear to be as simple as I thought and there was some argument over the validity of the his analysis.