Guest Post by Steven Goddard
We have all seen lots of pictures of the Eyjafjallajokull eruption now, with steam and ash billowing up in the air. The eruption started one month ago, and as the Guardian reports, The eruption of the Eyjafjallajokull volcano is unlikely to have any significant impact on climate but has caused a small fall in carbon emissions, experts say.
The Guardian editors seem to have forgotten that the volcano itself is spewing massive amounts of CO2 in the atmosphere. Perhaps their kinship with Plane Stupid is having an impact? Plane Stupid’s goal is to stop plane traffic in the UK, and they must be thrilled by the flight ban and the damage to the economy.
Added:
Volcano CO2 budget (CO2 is emitted independent of ash) ~200,000 tons per day X 30 days of eruption = 6,000,000 tons of CO2.
Plane CO2 Budget – assumes half of EU planes haven’t flown for the past six days 340,000 EU tons per day X 0.5 EU shutdown X 6 days = ~1,000,000 tons of savings.
People using alternative transportation (as Anthony and the BBC pointed out) as a replacement for aircraft – cars, trains, battleships , etc. ~1,000,000 tons of extra CO2 Is a battleship more “green” than a jumbo jet?
The total gain is 6,000,000 – 1,000,000 + 1,000,000 = 6,000,000 tons of excess CO2 from the volcano. The temporary aircraft shutdown has little or no net impact on CO2 emissions, but the volcano has a large impact.
Video and reader poll follow.
Below is a video chronology of the glacier and volcano, giving a feel of the events of the past month. First video shows what the glacier looked like prior to the eruption.
The next video shows the first night of the eruption – March 21. Note the similarity to Hawaiian volcanoes – lava fountains and little steam or ash.
By March 24, some steam and ash is starting to appear as glacial meltwater begins to mix with the magma.
By April 14, flash flooding from glacial melt began to pour down the side of the glacier.
The flooding was widespread and devastating downstream.
By April 17, the eruption was primarily steam, CO2 and ash.
Should climate modelers start differentiating between man made CO2 and “organic” natural CO2?
Reader Poll :
George Turner 08:41:19
Disregarding all the high fliers, I love your extra oxygen point, something no-one else seems to have picked up on, but Howarth et al, I hear the theme tune from MASH running through my head 😉
Hmm, Icelandic banks go bankrupt, then the country is set fire to.
It’s all an insurance fraud I tell you!
Bill Hartree (02:16:12) :
Your post makes it appear that you are commenting without having actually read my article above. I will post it for you again.
@kadaka (09:55:15) :
Yes, very interesting article. It further highlights that we’re just now starting to figure out the “unknown unknowns”, to mis-quote Donald Rumsfeld.
I had an article of Moonbat’s sneak up on me while reading the Sydney Morning Herald today. I shall read that journal no more, just in case it happens again.
He is telling us that the current level of aviation traffic is ‘unsustainable’. Tell Al Baby, and see if he’ll stop…..
Bernd Felsche (19:20:46) :
Hmmm …… that’s Strange ….
George E. Smith (17:06:32):
&
George E. Smith (16:43:50) :
Thanks for the comments, I’m glad we were able to help out. I, too, learn a lot in areas outside my expertise when reading the comments on this site, so I was glad to contribute some chemical knowledge.
On a topic related to CO2, can someone point me to a link where the radiative forcing factor for CO2 was derived? I’ve never run the numbers myself, but I have an idea on why it may be overestimated, so I wanted to check it out.
Thanks,
-Scott
Steven Goddard wrote: “Your post makes it appear that you are commenting without having actually read my article above”.
Steven, I was actually quoting not from your original posting but from a subsequent comment by you on the comments section, where you actually upped your original estimate of daily CO2 production from ~200,000 to 300,000 tonnes per day. I did actually read your article, which is how I got to know about the informationisbeautiful website: many thanks for introducing me to it!. My original point was to question your decision to go with a figure in the region of 150,000 to 300,000, based on “model data” from an eruption from a different volcano, rather than the 15,000 tonnes per day actually measured by vulcanologists from Eyja f.j. over the course of the last few days. I had assumed that you would have done as I did and investigated informationisbeautiful’s sources of information (for which they provide comprehensive links) for the 15,000, 150,000 and 300,000 figures, but in case you haven’t then you should be able to understand my comment better if you do so.
As for your claim that any reduction in emissions from planes would have been largely offset by emissions from cars, trains, buses and ships you may be right: I don’t feel I have the knowledge to comment either way on this.
Volcanic CO2 has a lower proportion of C14 than man made CO2.
I doubt that it makes any significant difference, certainly none that is measurable.
Gail Combs (18:33:07) :
‘We have a hothouse filled with corn plants that make
anti-sperm antibodies,’ said Epicyte president Mitch Hein.
Gail, I don’t know exactly what Epicyte’s anitbodies are, but as a result of normal digestive mechanisms, antibodies [a form of protein] are not absorbed intact into the human body intact, except for a brief period in neonates when [some?] antibodies in breast milk colostrum are absorbed intact:
http://www.vivo.colostate.edu/hbooks/pathphys/digestion/smallgut/absorb_aacids.html
Apparently only very short chain peptides, up to tripeptides = three aminoacids in chain – total, make it in.
Bill Hartree (08:25:26) :
If you look at the IIB spreadsheet linked from their site.
http://spreadsheets.google.com/ccc?key=0Aqe2P9sYhZ2ndERxaWs2TU1iaDU1QW9ldzBzQXBpbkE&hl=en_GB
you can see that the 15,000 figure was a “pre-eruption” number.
I wrote this letter to Dr. Ball, who had an excellent article in Canada Free Press:
Dr. Ball:
I enjoyed your article very much.
As a physical organic chemist of 40+ years, and an expert on liquid and vapor diffusion through solids and semi-solids, I have to comment about ice core CO2.
I will be very brief.
CO2 diffuses through solid ice. The diffusion coefficient, very slow, but relevant to geologic time, was determined 2 years ago at Scripps Oceanographic. The diffusion depends on the diffusion coefficient, temperature, and time, but it directly depends upon INITIAL CONCENTRATION according to Ficks’ first and second laws of diffusion. The diffusion proceeds, in a concentration dependent manner, dc/dt, until equilibrium is reached. According to these laws, diffusion will proceed until the outside concentration is approached asymptotically.
So, all ice core CO2, given enough time, will reach the same level! SO, the old cores will lose CO2 more, and faster yet if the concentration is high in the old core.
So the number assumed, of ice cores being 20% low, is a completely wrong supposition. If CO2 were very high in the past (had to be very high for dinosaurs to get so large, commensurate with the fast rate of plant growth in response to CO2), the CO2 would have been lost to our contemporary measurement. Has to be. It’s physics!
However, working backwards from Fick’s Second Law, if we know the age of the sample, and the current measurement of CO2, and assume a number for an average outside concentration, we can extrapolate, using a simple differential equation, to find the initial concentration now that we know the diffusion coefficient.
Bob Gyurik
Sanibel, FL
“”” Ron House (23:20:35) :
George E Smith and C=O=C vs C=O-C:
When diagramming a molecule, one shows how many bonds, not the 3D appearance of the bonds when looking from a particular angle. “””
Ron, of course I am; and always have been; well at least as far back as about 1950, aware that CO2 contains two double bonds and is a linear molecule, and that it was coventionally represented by O=C=O just as Steve has ita t the top of this thread; except in 1950, they did not have smiley faces on molecules. I believe I am also correct in saying that in 1950 I was certainly NOT aware, that H2O was bent at that all important 104.5 or so degrees; I’ve only been aware of that for less than half that time.
My O=C-O was a whimsical attempt to use the limitations of my keyboard to create what I thought was a reasonable 3-D “model” of a CO2 molecule, in which the right hand bond pair was viewed edge on. It was never intended to be a full quantum chromodynamics thesis on the structure of CO2; assuming anybody would ever bother to construct such an edifice.
The only “four bond” plastic atoms I have at my desk, are various colors of balls with tetrahedrally located holes, into which I can insert bendable plastic “links” to build “artist’s impression” models of the Zinc-Blende and Wuzite Crystal lattices of the common III-V compounds. I could also build the Diamond lattice for Carbon, Silicon or Germanium if I wanted to just build a zinc-Blende lattice with a single color balls. There is no elemental equivalent to the binary Wurzite lattice.
The Arsenides, Antimonides, and Phosphides of Boron, Aluminium, Gallium, and Indium, are all Zinc-Blende lattices; whereas the Nitrides of Aluminium Gallium, and Indium are all Wurzite lattices. Then of course there is Boron Nitride; the odd-ball, which can have either the Zinc-Blende lattice (Borazon) but usually has the BN lattice which is a lot like Graphite with hexagonal cellular layers; but the adjacent BN layers are displaced from the Graphite layers.
But if I use my plastic ball and rod pieces to make CO2, then I get the two bond pairs to the Oxygens at right angles to each other about the linear molecule axis. And the whole reason for trying to depict this structural form was to explain the two degenerate bending modes of the CO2 15 micron absorption as depicted in this animation:
http://science.widener.edu/svb/ftir/ir_co2.html
In those animations of the bending modes, it is assumed that the oxygen can move out of the plane containing the pair of bent spring bonds; but that the other oxygen would have to move out of a perpendicular plane containing its two bonds, giving the up-down, and side to side vibrations seen in the animations.
I presume that since the pair of bonds to the Oxygen can stretch as in either the symmetrical or assymmetrical stretch modes, that it is also possible to have one of the pair of Oxygen bods stretch while its companion shrinks, so that the O can warp sideways in the same plane of the two bonds; but this presumably would be a higher frequency mode of vibration than the 15 micron bend.
And as has been explained in detail by Scott, and Sjoerd, the reality is a lot more complicated than I can construct with my plastic balls, and flexible rods.
I’m familiar with the fact that organic chemists draw Benzene rings with alternating double and single carbon bonds around the ring; but that apparently that pattern isn’t static; so evidently one of those electrons can jump over a carbon into the adjacent CC space thereby moving the single and double bonds around dynamically. So how can you show that on a simple pictorial sketch; let alone try typing it on a keyboard.
Well this is all very interesting; but not too useful in deciding whether we are on our way to a CO2 tipping point; or whether the CO2 comes from a C3 breathing plant or a C4, or maybe from some trilobite’s remains; or an Arabian oil well.
I’m actually only casually interested in the origins of the carbon or whether it is man made or not; to me that is largely inconsequential; because I don’t believe that the CO2 Greenhouse effect (which I fully admit to) has any appreciable impact on global temperatures; compared to the total feedback control exerted by the bent H2O molecules; which alone, exists in earth’s atmosphere in all three phases of normal matter. Besides humans emit more H2O to the atmosphere than they do CO2; so we are guarding an empty hen house.
“”” bubbagyro (10:34:26) :
I wrote this letter to Dr. Ball, who had an excellent article in Canada Free Press:
Dr. Ball:
I enjoyed your article very much. “””
So Bob, I’m interested in the essence of your letter to Dr Ball.
First off, you say that Scripps determined the CO2 diffusion coefficient (presumably in ice) two years ago. I wonder if Dr Steve Piper had a hand in that. He’s a CO2 expert at Scripps; whom I know only though some fly fishing e-versations; and he has been kind enough to send me various papers on CO2.
Do you know if Scripps was able to determine any temperature coefficient of the diffusion coefficient.
But now, if I understand your above letter; you seem to be saying that the diffusion rate depends on the “initial” CO2 amount in the sample. Is this similar to the diffusion of impurities into say silicon, in the fabrication of semiconductor devices. In that technology we have several processes for getting some “lump” of impurity material (B or P say) into the Si; including Ion implantation; but then subsequent heat treatments will redistribute the “lump”, and in that case, the diffusion process does depend on the amount of impurity and its peak concentration in the original lump.
With the CO2 in ice thing; don’t they have a problem, that the distance from the “sample” to the ambient (atmosphere) must be largely unknown; unless they rely on the ice layers that presumably are laid down annually; but if the atmospheric CO2 is varying substantially over time, then it would seem they have a very complex deposition structure to subject to diffusion calculations.
Well maybe it is just a matter of how much supercomputer power you have access to.
Maybe you can comment on a related issue. The annual cyclic variation of atmospheric CO2 in the arctic; covering pretty much the entire arctic ocean to the pole, and maybe some of the surrounding land, has a peak to peak CO2 variation of aboput 18 ppm; which is three times the Mauna Loa amplitude.
Now I have postulated, that a possible cause or at least a contributor to this could be the melting and regrowth of the arctic sea ice. Assuming that the ocean surface water, must contain a lot of CO2 per Henry’s law, and the water being sub zero; upon freezing, it seems that CO2 along with the salt, must be excluded from the growing solid via some “segregation coefficient”. If the water CO2 content was near the equilibrium (saturation) value set by Henry’s law, then the addition of a considerable amount of CO2 that is being excluded from the growing ice, might then result in a lot of that CO2 escaping from the water into the atmosphere to comply with Henry’s law limits.
Now Dr Piper was not too moved by my postulate; and suggested that perhaps I needed reprogramming.
So perhaps Bob; you can enlighten us as to how much CO2 would be incorporated into the growing sea ice from the water; versus the amount that would remain behind in the water. The ice evidently is high purity fresh water, aside from brine inclusions in voids; so I wonder just what redistribution of the CO2 in the water as it freezes, would be expected to take place.
Don’t want to burden you with any chores; but if some of this is at your fingertips; it would be much appreciated to learn what happens.
George
E.M.Smith (14:51:55) :
And for all the folks talking about plants having preferential absorption of different isotopes remember that C3 vs C4 plants have different enzyme systems and thus different ratios. So you also get to figure out the historic ratio of these two plant metabolism types. For bonus points you get to figure out how both have evolved over time AND how both work in a differential way at different concentrations of CO2 and with different atmospheric ratios of C12, C13 and even C14 just for fun…
Ferdinand Engelbeen (00:53:48) :
Sorry I didn’t respond sooner, I was planting my victory garden! Ferdinand, I’m inclined to believe that we must agree to disagree. I’m entirely unconvinced that CO2 discrimination is measuring human interference through fossil fuel use with sufficient precision, especially within the short time-frame available. In addition to E.M. Smith’s contributions, there are two many confounding effects, some examples following.
For example, irradiance influences the isotopic ratio for marine algae. So have there been any studies relating tropical cloud cover to isotopic discrimination?
Abstract
The ratio of l*C : 13C was measured for Emiliania huxleyi cells grown under a range of irradiances in batch culture. Based on the assumption that HCO was the carbon source, the maximum discrimination against 13C in the decalcified E. huxleyi cells was 24.6?& at 4.8 mol photons m-* d-l and the minimum discrimination was 17.9?& at 0.5 mol photons m-* d-l. In calcified cells, the range of 13C isotope discrimination was
markedly lower (12-217~). In both calcified and decalcified cells, the carbon isotopic composition of and carbon isotopic discrimination by E. huxleyi was a significant linear function of irradiance from 0.5 to 4.8
mol photons m-* d- I. The relationship between isotopic discrimination and irradiance in E. huxleyi provides new evidence that the 13C of the oceanic POC samples should not be treated simply as a function of sea
surface temperature or [CO,],,. We propose that the P3C of E. huxleyi was controlled by irradiance through variation in the intracellular HC03- -derived CO2 supply which influenced the discrimination of ribulose
1,5-bisphosphate carboxylase/oxygenase (rubisco) against 13C.
The ability of the ocean to buffer the concentration of CO2 in the atmosphere through the so-called biological pump depends on the extent to which the photosynthetic rate of marine phytoplankton is limited by the concentration of CO2 in the water. If CO2 becomes available to phytoplankton by passive diffusion through the boundary layer around the cell, then the growth of large cells, which are believed to contribute disproportionately to the biological pump, could be limited by CO2 availability. However, many species appear to have the ability to circumvent diffusion control through the use of carbon-concentrating mechanisms (CCMs) such as active CO2 uptake, bicarbonate (HCO3-) transport, and carbonic anhydrase activity. These mechanisms are likely adaptations to the fact that the main carbon fixing enzyme, ribulose-1,5-bisphosphate carboxylase-oxygenase (Rubisco), is less than half saturated at normal seawater CO2 concentrations.
And the tiny fraction that man is producing has little affect on biological activity, the mole ratio figures are in dispute.
Isotopic disequilibrium experiments were also performed in the field to estimate the extent of photosynthetic bicarbonate (HCO3-) uptake in the oceans. The experiments were conducted in the Southern Ocean during the Southern Ocean Iron Experiment (SOFeX). In contrast to the results with P. tricornutum, approximately half of the photosynthetic inorganic carbon uptake was direct HCO3- uptake, the other half being direct CO2 uptake (passive and/or active uptake). A low-CO2 treatment induced an increase in uptake of CO2 through increased enzymatically mediated extracellular dehydration of HCO3- (carbonic anhydrase activity), which was at the expense of direct HCO3- transport across the plasmalemma. Because of the presence of CCMs, biological productivity in the Southern Ocean is unlikely to be directly regulated by natural or anthropogenic variations in atmospheric CO2 concentration. These results are consistent with stable isotope fractionation models and could have important implications for the global biogeochemical cycle of carbon.
For brevity, here are just blurbs from the results from other studies:
A review and experimental study of the various factors that influence CCM activity and therefore photosynthetic carbon isotope fractionation revealed that, other than CCMs, several factors that have been essentially ignored in the scientific literature may also contribute to the isotopic signature of photosynthetic organic matter. Isotopic fractionation during photosynthesis in P. tricornutum was found to be well correlated to changes in Rubisco enzyme kinetics. The contribution of carboxylases other than Rubisco to photosynthetic stable carbon isotope fractionation was also examined.
A multitude of factors may influence overall photosynthetic carbon isotope fractionation. Understanding these factors will be crucial to the use of isotopic analyses for paleo-CO2 reconstruction.
And, water deficiency (drought) affects the isotope discrimination, influencing terrestrial uptake and evolution:
Arndt SK, Wanek W. Use of decreasing foliar carbon isotope discrimination during water limitation as a carbon tracer to study whole plant carbon allocation. Plant Cell Environ. 25: 609-616 (2002)
Irradiance affects respiration isotope composition:
Barbour MM, McDowell NG, Tcherkez G, Bickford CP, Hanson DT. A new measurement technique reveals rapid post-illumination changes in the carbon isotope composition of leaf-respired CO2. Plant Cell Environ. 30: 469-482 (2007).
We know far less than we think we know.
George:
Yes, same as doping silicon. All gases diffuse into and through solids.
Diffusion does depend on “d” the thickness of the substrate. However, molecules “don’t know” what is happening on the outside, no matter how thick the substrate. Fick’s 2nd law assumes that the molecule diffusing is novel – in other words, that there is no molecule in the substrate through which it is diffusing.
The fact that the molecules “don’t know” means that the diffusion rate is proximal. For a substrate that already contains CO2, like the ice, then the diffusion depends upon ∂C, the immediate concentration difference. If, however, there is melting, or something “sucking molecules away” on the outside, then there will be a differential gradient that will affect the rate coming from the reservoir. The response time will depend upon the diffusion coefficient.
There is one other factor. Pressure. There is a gradient of pressure that can hinder diffusion, countering Fickian first order diffusion. Under a glacier, then, diffusion will be hindered. However, when the core is removed, then diffusion will go unabated.
Say, for example, during an ice age, CO2 and ice are laid down (CO2 is soluble in pure water at parts per hundred, so solubility is not a factor; the CO2 concentration of the atmosphere, then, is similar now to that trapped in the snow that has fallen, at say, a part per thousand), and the snow compacts into ice quickly (over tens or hundreds of years, not millennia). When the glacier melts, and pressure is reduced (again, hundreds of years), then the pressure within the bubbles in the core in question are under relatively high pressure.
This is why I cannot compute using Fick’s law because there are too many unknowns, Would need a Cray.
Yes, I believe it was Dr. Piper who did the Scripps work. If you know him, perhaps you could get his counsel on this.
stevengoddard (09:15:44): “If you look at the IIB spreadsheet linked from their site”
Steven, I find this sentence of your reply incomprehensible. What is “IIB”, and to whom does “their” refer?
The entry on the “pre-eruption” emission of CO2 contains no attribution, unlike most of the other entries, so I have no way of assessing its reliability. Perhaps I could help you out here by providing a reference: it’s actually in one of the links provided by the informationisbeautiful article to which I’ve referred you, but here it is: http://www2.norvol.hi.is/Apps/WebObjects/HI.woa/swdocument/1015769/Gas+report+-+Eyjafjallaj%C3%B6kull+2010.pdf
The data were gathered on 1st-2nd April, i.e. during the eruption and not “pre-eruption”. If you look at the bullet points towared the end of the article you will see that the emission of SO2 was 3000 tonnes per day and that the approximate molar ratio of CO2 to SO2 is 15:3. This actually means that the CO2 output would be more like 10,000 tonnes per day: informationisbeautiful’s figure was an over-estimate. Possibly, the author of the spreadsheet you cite, whose source remains a mystery to me, made the same mistake.
So, there you have it: a measurement-based figure for CO2 output during the eruption. As I have explained to you in my two previous comments, your 150,000 tonnes per day figure is not based on any measurements of Eyafjallajoekull, but rather on the speculative assumption that the current Eyja f.j. eruption is emitting at the same rate as a previous eruption of another, unnamed Icelandic volcano.
Would you care to comment?
So there you have it
bubbagyro (10:34:26) :
CO2 diffuses through solid ice. The diffusion coefficient, very slow, but relevant to geologic time, was determined 2 years ago at Scripps Oceanographic. The diffusion depends on the diffusion coefficient, temperature, and time, but it directly depends upon INITIAL CONCENTRATION according to Ficks’ first and second laws of diffusion. The diffusion proceeds, in a concentration dependent manner, dc/dt, until equilibrium is reached. According to these laws, diffusion will proceed until the outside concentration is approached asymptotically.
I think that I have read the article too (or were it Japanese tests I have read?). They measured the diffusion speed of ice at the same circumstances of the deep ice core of Vostok.
If I remember well, they compared the high pressure and low temperature CO2 diffuse speed against ambient pressure. Quite a difference with the real circumstances, where there is no practical pressure difference between ice at 2000 m and 2001 m depth. The same point for CO2 levels: the diffusion speeds I do remember were so low that the CO2 partial pressure difference over a meter of ice is practically irrelevant as driving force. The more that CO2 levels did go up and down over time, thus diffusion at the top layers would have been two-ways.
More important, even over 800,000 years of layers, the ratio between CO2 levels and temperature (proxy) didn’t change over time: for each glacial – interglacial transition, CO2 goes up and down with temperature (with a lag). If there was any (vertical) migration, the CO2 levels would be smeared out and the ratio would diminish with each transition 110,000 years further back in time.
Further, none of the ice cores from Antarctica which are used show any remelt of layers (with a few exceptions), relaxation is done at -20 C for up to a year (by far not long enough for the migration of CO2) and measurements are done by cold grating under vacuum over a cold trap, effectively removing any CO2 from any liquid water at the ice core’s surface layer.
Ice cores with very different circumstances of temperature, precipitation and salt/dust inclusions show the same CO2 levels at the same gas age for overlapping periods, the most recent high accumulation ones (Law Dome) have an overlap of 20 years with the South Pole atmospheric measurements.
Last but not least, CO2 levels in ice cores are measured at 180-300 ppmv. Today we measure 390 ppmv in the atmosphere. Backcalculating would mean that CO2 levels in the past would have been even lower, if migration from the outside world to the inside ice core would have occured…
Tim Clark (13:07:41) :
Sorry I didn’t respond sooner, I was planting my victory garden! Ferdinand, I’m inclined to believe that we must agree to disagree. I’m entirely unconvinced that CO2 discrimination is measuring human interference through fossil fuel use with sufficient precision, especially within the short time-frame available. In addition to E.M. Smith’s contributions, there are two many confounding effects, some examples following.
The examples you did give were about the d13C changes in organic carbon, which is not of interest here, as total biolife on earth (including animals and ocean creatures) produces more oxygen than it uses. That means that the bio world uses 12C and increases the 13C/12C ratio and that the bio world removes CO2 from the atmosphere. Thus the bioworld as a whole is not responsible for the increase of CO2 in the atmosphere, neither for the d13C decline we measure at least in the past 50+years.
The (deep) oceans have a higher d13C ratio in CO2 than in the current atmosphere, even taking into account the (two-way) isotopic fractionation between water and air at the ocean’s surface. Thus oceans can’t be the cause of the increase of CO2 in the atmosphere, or we should see a d13C increase.
d13C ratio’s from the ancient atmosphere are measured in ice core gas composition and doesn’t change with more than 0.4 per mil over glacial-interglacial transitions. When temperature and CO2 level goes up, d13C level goes up. Until some 150 years ago: CO2 goes up, but d13C level goes sharply down (in ratio with fossil fuel use) now already 1.4 per mil lower than during the whole Holocene.
d13C ratio’s from the oceans are measured in coralline sponges, which is inorganic carbon built from (bi)carbonate, without changing the isotopic composition compared to the surrounding seawater (coccolith shells are similar at near zero per mil d13C). These also show little variation up to about 1850 (+/- 0.1 per mil) and a sharp decline thereafter. Again in ratio to fossil fuel use.
Thus as neither biolife, nor the oceans are the source for the CO2 increase, neither of the d13C decline and both changes track fossil fuel use with an almost perfect fit, there is little doubt that humans are responsible for the increase of CO2 in the atmosphere.
That doesn’t imply that the effect of the increase is disastrous, that is a complete separate discussion.
Tim Clark (13:01:32) :
I don’t think you meant biochemical and then inferred a physical chemist would know. You should ask someone who has had Enzymology; and actually it makes 2.03% difference from corn chloroplasts in one of the most quoted pioneering work (peer reviewed ;~P)
Ferdinand Engelbeen (13:53:58) :
The story doesn’t determine what caused the fractionation in the ultimate enzymic reactions (interesting that it is the bicarbonate ion which is mainly used). The first fractionation at the air-water boundary indeed is a matter of kinetics (the same happens at the air-ocean border in both directions), but as for many biochemical reactions size and 3D-structure is important, I still wonder if that also is the case for 13CO2 vs. 12CO2 incorporation.
Ferdinand,
These folks indicated it is a little of both, but weighted toward RUBISCO.
Where ci is the intercellular leaf CO2 concentration; δ13Cair is about –8‰VPDB, a is the fractionation caused by the slower diffusion 13CO2 relative to 12CO2 (4.4‰), b is the fractionation caused by discrimination of RuBP carboxylase against 13CO2 (27‰) and ca is the atmospheric CO2
concentration. Field observations of average diurnal ci values correlated with whole-leaf carbon isotope values support this relationship.
Ferdinand:
I do not think that the last paragraph is true. In accordance with the geologically slow diffusion rate, the recent CO2 levels, measured by different proxies, are very low. We are IMHO in a CO2 starved state compared to the dinosaur era, certainly, and maybe in the last couple hundred thousand years. The “back diffusion” conditions you mentioned would not have existed except for thousands year times. Not enough time, IMO, for the high CO2 content in the ice to have diffused out in equilibration with the very recent concentration.
According to diffusion physics, any putative high CO2 concentrations in the past would be long lost to our measurement. We do know that high concentrations of CO2 did exist in the past, the question is when. We certainly could not see that by current methodologies.
stevengoddard (09:15:44):
Steven, After visiting informationisbeautiful I’ve worked out who “their” refers to in your message. You are taking the 15,000 tonnes figure as “pre-eruption” on the authority of … the informationisbeautiful website.
So that particular question of mine is answered. If you could still comment on the rest of my posting of 14:05:32 I’d be most grateful.
“”” bubbagyro (13:13:42) :
George:
Yes, same as doping silicon. All gases diffuse into and through solids. “””
Thanks Bob; I have always thought of the simple diffusion as being akin to the “ballroom dancing” effect, in that the movement of individual “dancers” is influenced by where the holes are on the dance floor; so everybody steers towards the empty space; which of course thereupon moves to somewhere else. So local concentration gradients point to which direction is downhill, and the rolling stone heads in that direction at a rate that reflects the steepness of the hill.
I was fortunate enough to get my early solid state Physics directly from Dr Andrew Grove, former President and co-founder of Intel; when we both were at Fairchild Semiconductor.
In his classic text on the Physics and Technology of Semi-Conductor Devices Grove gives:- C(x,t) = Cs.erfc (x/2sqrt(Dt)) for the one dimensional diffusion in x and t (time), with Cs as the fixed surface (predep) concentration; yielding the compementary error function diffusion profile.
This step is then followed by a so-called Drive in Diffusion where a regrown oxide blocks off the surface, trapping the fixed “clump” of dopant, which then redistributes in a Gaussian distribution, which gives:-
C(x,t) = (Q/sqrt(piDt))exp (-x^2/4Dt) ; Q being the fixed quantity of impurity in the clump. The surface concentration constantly drops from the initial Cs level as the dopant progresses into the crystal.
I believe that this analysis relies on an assumption that the dopant species, is in fact incorporated into the crystal lattice which results then in a local charge concentration as well since the dopants are not isoelectronic with the native crystal (silicon) species, so either make it (p) type (Boron) or (n) type (phosphorous). So I beleive there is both a concentration gradient driving force and also a Coulomb force due to the charged foreign species. If the impurities are interstitial, as they can be in in very high doping levels or in weird crystals like Gallium Arsenide, then the interstitial impurities diffuse under their own laws; which are more elaborate than the above.
But all that is rather unrelated to CO2 diffusion through ice, since I don’t quite see any Coulomb component to the driving force, as the CO2 molecules are hardly likely to be incorporated into the ice lattice; well I think that’s the case anyway.
Thanks for the insight; fancy that, Dr Steve may be the culprit. He seems like a very nice chap based on my exchanges with him. We are both avid salt water fly fisherfolk. I’ll have to bend his ear about the CO2/ice diffusion coefficient.
He already told me that his primary CO2 interests; were NOT actually directed towards any climatic interests; although he indicated that some of his CO2 colleagues at Scripps were. Like I said Steve yanked my chain a bit, and said I needed reprogramming. But then I suspect that scripps is one institution where it is not fashionable to be bucking the party line. Wouldn’t mind working there though, since La Jolla, and San Diego, has much better fishing that San Francisco. Well you’ve got the best fishing right in your back yard; I have a great affinity for tarpon on the fly.
George
Hooked a tarpon last year on light tackle from the shoreline, using shrimp, but of course he snapped the line.
Fairchild? I used Fairchild people in the 80s. I patented an electronic CMOS device for dosing medicine automatically for cattle in the 3rd world, so people would not have to round them up to dose once a month. The fellow who actually designed the chip to my specs, was the one who developed the deep channel CMOS chip for musical greeting cards. The rest of the solid state and mechanical components was built by a group called I2P.
Bill Hartree (14:05:32) :
IIB = Information Is Beautiful. The spreadsheet is linked in the article in question.