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)
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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.
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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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So we don’t know accurately just how much CO2 volcanoes are putting out?
I suspect that we don’t know accurately how much CO2 humanity is putting out either…
What has amazed me are the volcanoes that quietly emit pure liquid CO2 at depth in the ocean. The high pressure keeps the CO2 liquified. In fact, I read a paper a while back that concluded that it was quite possible that large pools of liquid CO2 could have sat relatively undisturbed on the bottom for tens of thousands of years in places in the South Pacific due to the circulation patterns shutting down during the last glacial.
Not to mention the + 100.000 undersea volcanoes , as only 10 % of the deep seas are scanned this could be dtamaticly more.
150 volcanoes only? Aren’t there thousands of volcanoes on the ocean floor as active?
Not to mention the midocean ridge vents that are…horrors…acidifying the oceans.
I’m surprised at how poorly the budgets for most volatiles, such as CO2, sulfur, and chlorine balance. One could probably conclude that there are widely distributed, low density, exhalations from the mantle that we fail to see when there are dramatic sources such as volcanoes, ocean ridges, and so forth to distract us. For instance, where’d the commercial gas deposits containing mainly CO2 and helium come from?
crosspatch says:
November 16, 2013 at 2:23 pm
crosspatch nails it on the head. Do we even know how many volcanoes exist beneath the ocean?
http://wattsupwiththat.com/2011/08/11/undersea-volcanoes-might-be-more-common-than-previously-thought/
or this;
http://wattsupwiththat.com/2013/09/06/scientists-confirm-existence-of-largest-single-volcano-on-earth-massive-underwater-volcano-rivals-biggest-in-solar-system/
Here is settled science.
What about the deep sea volcanic vents? Are they better understood?
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.
w.
Shrinking Mankind’s contribution, percentage-wise. How nice. The usual suspects will have to run around and “discover” that some industry somewhere produces sooo much more CO2 than they thought, just to try and balance it up again. Poor dears, it’s just work, work, work nowadays.
Willis Eschenbach says:
November 16, 2013 at 2:43 pm
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Your comment came up just as mine went into moderation. Dang, I thought maybe our percentage had shrunk. No matter. 🙂
Third type of undersea volcanic eruption discovered:
http://www.sciencedaily.com/releases/2013/01/130121083215.htm
Up to 80% of all volcanic activity on earth takes place at deep-sea, mid-ocean ridges, so this could make more than bubbles.
Six fold? Minor adjustment… 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?
@crosspatch: “What has amazed me are the volcanoes that quietly emit pure liquid CO2 at depth in the ocean.”
That is ridiculously neat. Thanks for the info.
I would add another important factor the equation of level of C02 emission: that of the CO2 gas which exists in equilibrium with various carbonate minerals and carbonate rich rocks within the subsurface over varying temperatures and pressures around magma chambers, mid ocean ridge volcanic systems, marine and continental volcanic arcs, and active volcanoes.
The volume of material involved is enormous. Exploration geologists routinely study these carbonate minerals in rocks around volcanos as different carbonate minerals precipitate at different temperatures and so give an idea of the temperature at which any carbonate alteration and precipitation occurred, thereby giving an indicator for other minerals of economic interest formed during such whole rock alteration such as gold and copper.
Most of the world’s copper derives from extinct volcanic systems, precipitated in rocks around extinct volcanos which also often have varying degrees of associated carbonate alteration. The extent of carbonate alteration around these extinct volcanoes is of the order of several km2 or more. And there are literally tens of thousands of volcanoes, most of which are under the ocean.
The C02 which exists in equilibrium in huge volumes at varying temperatures around volcanoes will precipitate into a more carbonate-enriched rock as various carbonate mineral types, if there is a temperature and/or pressure change. Lower temperature carbonates include siderite and ankerite, and moderate to higher temperature carbonates include rhodochrosite, calcite, and dolomite. The carbonate can come to make up around 10% of so by volume of the rock, all of which involves removal and/or input of C02 from either seawater, from the surrounding rocks, or from the underlying magma chamber. This is particularly the case within the ocean, as the ocean itself acts as a huge source of dissolved carbonate, and marine volcanic sequences are often enriched in carbonate for that reason. (But there are also carbonate rich rocks associated with some continental volcanoes, so much so that some continental type volcanoes are called ‘carbonitite volcanoes’ but my memory of these from university days is thin).
The amount of dissolved C02 which exists in equilibrium with subsurface volcanoes far exceeds the small amount which exchanges with the atmosphere due to human activity. As such, it is unlikely that oceans would acidify very much with additional c02 in the atmosphere, but there is a paucity of studies which addresses this question.
More estimations. The science is settled dontcha know.
Surprise! But we must act now! It’s worse than we thought!
Don’t you get it? The natural CO2 sources are perfectly balanced by natural CO2 sinks–it’s the unnatural human contribution that throws things out of balance. Geez.
“It caps a staggering trend: A six-fold increase in just two decades.”
I have to wonder if the author here is getting mixed up with estimates quoted in tons of carbon, rather than CO2. He gives no references for his earlier figures. The new paper by Burton (637 Mt/yr) cites older estimates, and there is no such super rapid trend. He quotes Mörner and Etiope (2002) (600 MTons/yr), and Marty and Tolstikhin (1998) 440 Mt/yr.
Much depends upon what is meant by “active”. As our host sagely notes, even geologically inactive volcanoes are still chemically-active, ie releasing gases. So I wouldn’t put much store in the known known figure of 150 active volcanoes.
Adapted from “Volcano Discovery” site”
The exact number of volcanoes is unknown. It also depends on the definition of a “volcano”: for instance, there are “volcanic fields” that comprise hundreds of individual eruption centers (such as conder cones, maars, shield volcanoes) that are all related to the same magma chamber & that may or not be counted as a single “volcano”.
Millions of volcanoes have probably been active during the whole lifespan of the earth. During the past 10,000 years, about 1500 volcanoes on land have been known active, while the even larger number of submarine volcanoes is unknown. At present, there are about 600 volcanoes with known eruptions during recorded history, while about 50-70 volcanoes are active (erupting) each year. At any given time, an average of about 20 volcanoes is erupting.
The assumption is that most of the CO2 comes from the crater. The literature shows this is not true. Here are two examples.
“Furthermore, we find that diffuse emissions of CO2 from the upper flanks of Etna are magma-derived and are of a similar magnitude to those emitted from the crater plume. This observation, as well as others, verifies the idea that extensive diffuse release of magmatic CO2 may occur in volcanically active regions a process that needs to be taken into account when evaluating the volatile budget of subaerial volcanism.”
http://www.researchgate.net/publication/232761335_Eruptive_and_diffuse_emissions_of_CO2_from_Mount_Etna
“Over geological time scales, Earth degassing has a significant impact on atmospheric carbon dioxide (CO2) concentrations, which are an important component of global carbon cycle models. In Tibet, structural conditions and associated widespread geothermal systems lead to carbon dioxide degassing during geothermal water migration. We characterized the hydrochemical conditions of two geothermal fields on the Tibetan Plateau.”
http://www.researchgate.net/publication/225226304_Carbon_dioxide_degassing_flux_from_two_geothermal_fields_in_Tibet_China
This is diffusion around phreatic volcanoes with much heavier and denser lava than for ocean crust volcanoes like Hawaii. No wonder Keeling has to make such dramatic manipulative adjustments to his Mauna Loa readings.
” … it would still only be about 4% of human emissions.”
To be honest Willis, I have real trouble believing the estimates of either category. Given the lies, distortions, guesses, and bias of “climate scientists” for the past several decades there seems to be no reason to believe any estimate they provide.
Do you have any credible evidence?
Volcanism increases after ice sheets melt, which is another means by which CO2 trails rather than leads temperature:
http://www.gizmag.com/climate-volcanic-activity-link/25520/
“In times of global warming, the glaciers are melting on the continents relatively quickly,” says Dr. Marion Jegen, a geophysicist from GEOMAR. “At the same time the sea level rises. The weight on the continents decreases, while the weight on the oceanic tectonic plates increases. Thus, the stress changes within in the earth to open more routes for ascending magma.”
Because the rate of global cooling at the end of warm phases is much slower compared to the rate of warming at the beginning of such phases, there are less dramatic stress changes and less volcanic activity during these times.
“If you follow the natural climate cycles, we are currently at the end of a really warm phase,” says Dr. Steffen Kutterolf, the lead author of the study. “Therefore, things are volcanically quieter now.”
Assuming the above refers to Millions of Metric Tons, MMT, comparing this to the IPCC 2001 estimations (Table 3) of total sources and absorption of CO2, the IPCC gives Natural sources as 770,000 MMT and Anthro sources as 23,100 MMT for the 90s. A 2-600 MMT difference is inconsequential if these numbers are real. Is one set of numbers off some orders of magnitude? The whole 600 MMT is less than 0.1% of 800,000 MMT/ year annual input the IPCC claims.
Willis
But IF a good proportion of co2 stays in the atmosphere for hundreds or thousands of year the volcanic contribution to the co2 atmospheric levels over the centuries will be very large. Mans contributions until recent decades has been rather small
Tonyb
Just read the linked article. The authors’ estimate, though higher than past guesses, is most likely very low. They assume more CO2 from land & lake volcanoes than from hydrothermal & other submarine volcanoes, though of course the ocean has not been well sampled, as they admit.
Also, I’m disturbed by the unrepresentative sample of land volcanoes, which is skewed to Italy & the US. Only one Chilean volcano is included in the small sample, despite the number of highly active volcanoes there, the most earthquake prone region on earth.
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
OK, I’m going to practice “climate science” now & produce my own estimate of volcanic CO2, after the school of Cook & Lewandowsky, only starting from numbers with some basis in observations rather than made up or non-existent figures. If in this study roughly 300 million tonnes come from the land & 300 from the sea, for a total around 600 MT, my consensus climate scientific guess is 2700 MT, thanks to a quadrupling of the maritime component. But given differences in oceanic crust from continental, I’m going to add on another 300 MT as a fudge factor, applying the statistically now accepted best practice of the Cook-Lewandowsky-Mann transform function, for a final estimate of 3 GT of volcanic-origin CO2 per annum. Now I need some pals to review my “work”.