Studies of Carbon 14 in the atmosphere emitted by nuclear tests indicate that the Bern model used by the IPCC is inconsistent with virtually all reported experimental results.
Guest essay by Gösta Pettersson
The Keeling curve establishes that the atmospheric carbon dioxide level has shown a steady long-term increase since 1958. Proponents of the antropogenic global warming (AGW) hypothesis have attributed the increasing carbon dioxide level to human activities such as combustion of fossil fuels and land-use changes. Opponents of the AGW hypothesis have argued that this would require that the turnover time for atmospheric carbon dioxide is about 100 years, which is inconsistent with a multitude of experimental studies indicating that the turnover time is of the order of 10 years.
Since its constitution in 1988, the United Nation’s Intergovernmental Panel on Climate Change (IPCC) has disregarded the empirically determined turnover times, claiming that they lack bearing on the rate at which anthropogenic carbon dioxide emissions are removed from the atmosphere. Instead, the fourth IPCC assessment report argues that the removal of carbon dioxide emissions is adequately described by the ‘Bern model‘, a carbon cycle model designed by prominent climatologists at the Bern University. The Bern model is based on the presumption that the increasing levels of atmospheric carbon dioxide derive exclusively from anthropogenic emissions. Tuned to fit the Keeling curve, the model prescribes that the relaxation of an emission pulse of carbon dioxide is multiphasic with slow components reflecting slow transfer of carbon dioxide from the oceanic surface to the deep-sea regions. The problem is that empirical observations tell us an entirely different story.
The nuclear weapon tests in the early 1960s have initiated a scientifically ideal tracer experiment describing the kinetics of removal of an excess of airborne carbon dioxide. When the atmospheric bomb tests ceased in 1963, they had raised the air level of C14-carbon dioxide to almost twice its original background value. The relaxation of this pulse of excess C14-carbon dioxide has now been monitored for fifty years. Representative results providing direct experimental records of more than 95% of the relaxation process are shown in Fig.1.
Figure 1. Relaxation of the excess of airborne C14-carbon dioxide produced by atmospheric tests of nuclear weapons before the tests ceased in 1963
The IPCC has disregarded the bombtest data in Fig. 1 (which refer to the C14/C12 ratio), arguing that “an atmospheric perturbation in the isotopic ratio disappears much faster than the perturbation in the number of C14 atoms”. That argument cannot be followed and certainly is incorrect. Fig. 2 shows the data in Fig. 1 after rescaling and correction for the minor dilution effects caused by the increased atmospheric concentration of C12-carbon dioxide during the examined period of time.
Figure 2. The bombtest curve. Experimentally observed relaxation of C14-carbon dioxide (black) compared with model descriptions of the process.
The resulting series of experimental points (black data i Fig. 2) describes the disappearance of “the perturbation in the number of C14 atoms”, is almost indistinguishable from the data in Fig. 1, and will be referred to as the ‘bombtest curve’.
To draw attention to the bombtest curve and its important implications, I have made public a trilogy of strict reaction kinetic analyses addressing the controversial views expressed on the interpretation of the Keeling curve by proponents and opponents of the AGW hypothesis.
(Note: links to all three papers are below also)
Paper 1 in the trilogy clarifies that
a. The bombtest curve provides an empirical record of more than 95% of the relaxation of airborne C14-carbon dioxide. Since kinetic carbon isotope effects are small, the bombtest curve can be taken to be representative for the relaxation of emission pulses of carbon dioxide in general.
b. The relaxation process conforms to a monoexponential relationship (red curve in Fig. 2) and hence can be described in terms of a single relaxation time (turnover time). There is no kinetically valid reason to disregard reported experimental estimates (5–14 years) of this relaxation time.
c. The exponential character of the relaxation implies that the rate of removal of C14 has been proportional to the amount of C14. This means that the observed 95% of the relaxation process have been governed by the atmospheric concentration of C14-carbon dioxide according to the law of mass action, without any detectable contributions from slow oceanic events.
d. The Bern model prescriptions (blue curve in Fig. 2) are inconsistent with the observations that have been made, and gravely underestimate both the rate and the extent of removal of anthropogenic carbon dioxide emissions. On basis of the Bern model predictions, the IPCC states that it takes a few hundreds of years before the first 80% of anthropogenic carbon dioxide emissions are removed from the air. The bombtest curve shows that it takes less than 25 years.
Paper 2 in the trilogy uses the kinetic relationships derived from the bombtest curve to calculate how much the atmospheric carbon dioxide level has been affected by emissions of anthropogenic carbon dioxide since 1850. The results show that only half of the Keeling curve’s longterm trend towards increased carbon dioxide levels originates from anthropogenic emissions.
The Bern model and other carbon cycle models tuned to fit the Keeling curve are routinely used by climate modellers to obtain input estimates of future carbon dioxide levels for postulated emissions scenarios. Paper 2 shows that estimates thus obtained exaggerate man-made contributions to future carbon dioxide levels (and consequent global temperatures) by factors of 3–14 for representative emission scenarios and time periods extending to year 2100 or longer. For empirically supported parameter values, the climate model projections actually provide evidence that global warming due to emissions of fossil carbon dioxide will remain within acceptable limits.
Paper 3 in the trilogy draws attention to the fact that hot water holds less dissolved carbon dioxide than cold water. This means that global warming during the 2000th century by necessity has led to a thermal out-gassing of carbon dioxide from the hydrosphere. Using a kinetic air-ocean model, the strength of this thermal effect can be estimated by analysis of the temperature dependence of the multiannual fluctuations of the Keeling curve and be described in terms of the activation energy for the out-gassing process.
For the empirically estimated parameter values obtained according to Paper 1 and Paper 3, the model shows that thermal out-gassing and anthropogenic emissions have provided approximately equal contributions to the increasing carbon dioxide levels over the examined period 1850–2010. During the last two decades, contributions from thermal out-gassing have been almost 40% larger than those from anthropogenic emissions. This is illustrated by the model data in Fig. 3, which also indicate that the Keeling curve can be quantitatively accounted for in terms of the combined effects of thermal out-gassing and anthropogenic emissions.
Figure 3. Variation of the atmospheric carbon dioxide level, as indicated by empirical data (green) and by the model described in Paper 3 (red). Blue and black curves show the contributions provided by thermal out-gassing and emissions, respectively.
The results in Fig. 3 call for a drastic revision of the carbon cycle budget presented by the IPCC. In particular, the extensively discussed ‘missing sink’ (called ‘residual terrestrial sink´ in the fourth IPCC report) can be identified as the hydrosphere; the amount of emissions taken up by the oceans has been gravely underestimated by the IPCC due to neglect of thermal out-gassing. Furthermore, the strength of the thermal out-gassing effect places climate modellers in the delicate situation that they have to know what the future temperatures will be before they can predict them by consideration of the greenhouse effect caused by future carbon dioxide levels.
By supporting the Bern model and similar carbon cycle models, the IPCC and climate modellers have taken the stand that the Keeling curve can be presumed to reflect only anthropogenic carbon dioxide emissions. The results in Paper 1–3 show that this presumption is inconsistent with virtually all reported experimental results that have a direct bearing on the relaxation kinetics of atmospheric carbon dioxide. As long as climate modellers continue to disregard the available empirical information on thermal out-gassing and on the relaxation kinetics of airborne carbon dioxide, their model predictions will remain too biased to provide any inferences of significant scientific or political interest.
References:
Climate Change 2007: IPCC Working Group I: The Physical Science Basis section 10.4 – Changes Associated with Biogeochemical Feedbacks and Ocean Acidification
http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch10s10-4.html
Climate Change 2007: IPCC Working Group I: The Physical Science Basis section 2.10.2 Direct Global Warming Potentials
http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch2s2-10-2.html
GLOBAL BIOGEOCHEMICAL CYCLES, VOL. 15, NO. 4, PAGES 891–907, DECEMBER 2001 Joos et al. Global warming feedbacks on terrestrial carbon uptake under the Intergovernmental Panel on Climate Change (IPCC) emission scenarios
ftp://ftp.elet.polimi.it/users/Giorgio.Guariso/papers/joos01gbc[1]-1.pdf
Click below for a free download of the three papers referenced in the essay as PDF files.
Paper 1 Relaxation kinetics of atmospheric carbon dioxide
Paper 2 Anthropogenic contributions to the atmospheric content of carbon dioxide during the industrial era
Paper 3 Temperature effects on the atmospheric carbon dioxide level
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Gösta Pettersson is a retired professor in biochemistry at the University of Lund (Sweden) and a previous editor of the European Journal of Biochemistry as an expert on reaction kinetics and mathematical modelling. My scientific reasearch has focused on the fixation of carbon dioxide by plants, which has made me familiar with the carbon cycle research carried out by climatologists and others.
Greg Goodman says:
July 4, 2013 at 5:13 am
Where is the study of “individual CO2 molecule” coming from. These data are from bulk measurements mainly in NZ and Norway. Absolutely NO ONE is studying this at the molecular level.
Greg, you are misinterpreting what Willis means: the residence time is the average time that any molecule in the atmosphere spends in the atmosphere before being catched by some tree or by the oceans surface. One human emitted molecule from burning fossil fuel can be catched within a minute by the next nearby tree, while another can reside in the stratosphere for centuries. But the average residence time for any molecule and all molecules of whatever origin in this case is about 5 years:
residence time = mass / inflows = mass / outflows = 800/150 = 5.33 years.
That means that about 20% of all CO2 molecules in the atmosphere per year are exchanged with CO2 molecules from other reservoirs.
The above 14C decay rate is one of the results of this exchange rate, but is longer, because part of the exchange comes back in the following years from the ocean surface and vegetation decay (mainly leaves). Only deep sea exchanges do reduce the 14C ratio continuosly.
But the net result, if inflows = outflows is zero change in total CO2 mass in the atmosphere.
In contrast, any excess injection of CO2 from any source will increase the CO2 levels in the atmosphere, which will lead to less release and more absorption of CO2 from/into the oceans (and more uptake by vegetation). The increase in the atmosphere thus will lead to a distortion of the equilibrium: inputs and outputs are not equal anymore. The decay rate of such an excess will be given by:
Tau = excess / (outflows – inflows) = 210 / 4 = 52.5 years
Quite a difference with the residence time of 5 years or the 14C decay time of 14 years…
The point is that the residence time says next to nothing about the behaviour of an impulse of extra CO2 mass in the atmosphere…
Creating some arbitrary construct like e folding or pulse half life merely obscures the reality that we are talking about individual molecules, after all. Unless you can show why an individual 14CO2 will behave differently than average for its proportion of a pulse or whatever construct you wish, the results are one and the same.
Edim says:
July 4, 2013 at 7:10 am
Ferdinand, for some reason there is a good correlation between CO2 annual (and longer) change and temperature level. Roughly, dC = C*T. So, after integrating, the change in atmospheric CO2 and the area under the temperature curve are proportional. There is a CO2 annual change ‘hiatus’ just like the global temperature anomaly one.
The short term correlation doesn’t change, no matter if you detrend the whole 50 years of data or not. The integral fits the multidecadal change only by shifting the baseline until the two match (which is what Phil already said), that is curve fitting, and has no physical basis.
The problem is that both emissions and temperature increased over the 50 year period, so any increase of CO2 in the atmosphere can theoretically be from any of them or from both in any ratio.
As the emissions are about twice the increase in the atmosphere, I’ll bet on the emissions, but pure theoretically, it is possible that the reaction time of the sinks is so fast to any disturbance that an enormous increase in sources is responsible for the increase, dwarfing the increase in human emissions to peanuts.
Assuming that was the case, then the increase in natural emissions should mimic the human releases all over the years, thus increase in ratio with the human emissions over time.
As human emissions per year more than doubled in the period 1960-2012 with accurate measurements, the natural inputs should have been doubled too, as good as the natural sinks, leaving only currently 4 GtC/year (2 ppmv/year) extra in the atmosphere.
A doubling of the total of all sources and the total of all sinks results in a halving of the residence time since 1960. Buth there is no change in residence time visible in the 14C bomb spike decay, or any other estimate of the residence time. If you separate the pre-1985 estimates from the post-1985 residence time estimates, the post-1985 residence times are even slightly longer (the total CO2 mass increased, the fluxes didn’t?). Thus where is the increase in natural fluxes?
If the natural fluxes didn’t increase over time, then the only cause of the increase are the human emissions…
gymnosperm says:
July 4, 2013 at 11:33 am
Perhaps one needs to have had experiments gone awry when water is left even a few minutes exposed to ambient air to appreciate how unphysical a sustained average 7 microatm pCO2 differential between the water and air is…
The problem is that the diffusion of CO2 in water is very slow. For a water drop no problem, for 100 meter of seawater no way. Therefore one need wind to mix the upper layer all around and with the atmosphere above it. Even with wind and 7 microatm pressure difference it needs 2 years to get a new equilibrium between the “mixed” layer of the oceans and the atmosphere. But as the atmospheric CO2 continuous increases, the oceans always are somewhat behind the atmosphere…
Why would this be true? How is 14C discriminated in the mass? If anything its mass proportion should be increased by biological rejection.
The 14C decay rate is 14 years, the excess mass decay rate is 52,5 years. The first is mostly based on the residence time and is not applicable to a change in mass, as the extra mass from a doubling of 10^-22 compared to 12C is negligible. That is the base error of Gösta Pettersson in this article…
Anyway, the Bern model is wrong.
Agreed, but the 14C model is wrong too…
Gene Selkov says:
July 4, 2013 at 10:55 am
Richard M asks: “Has anyone studied biological activity in ice?”
There is no active life in ice. Life relies on liquid water both inside and outside for structure maintenance and for the transport of materials. Under freezing conditions, chemical degradation is the only change. You can find spores and pollen in ice and even much larger organisms like fish and reptiles, some of which can thaw without damage, but there is no active life. No transport, no synthesis; only slow decay.
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Respectfully beg to differ.
Pockets of liquid water exist within ice which support life. Maybe it’s a semantic distinction as to what constitutes being “in” ice.
But then there are also microbes & even lichens which actually live in ice, with their liquid water worlds within themselves rather than outside.
http://www.astrobio.net/pressrelease/1737/life-in-ice
It’s possible if not probable that life itself developed within ice.
gymnosperm says:
July 4, 2013 at 12:26 pm
Creating some arbitrary construct like e folding or pulse half life merely obscures the reality that we are talking about individual molecules, after all. Unless you can show why an individual 14CO2 will behave differently than average for its proportion of a pulse or whatever construct you wish, the results are one and the same.
Besides some partitioning between the different isotopes at the air-water border and some biological partitioning, all carbon isotopes behave the same. What is different is that residence time (throughput, exchange rates) has very little in common with excess decay rates.
It is similar to the difference between the turnover of a bussiness (which is shown by the 14C decay) and the profit (or loss) of a bussiness (which is shown by the excess CO2 decay)…
PS: I should note that it’s unclear from the article (not the paper itself) whether the lichen grow only on rock in the volcano or in the ice as well. But there’s no doubt about the microbes.
Ferdinand,
All you are doing is taking an arbitrary group of molecules and defining it as “mass” in relation to another arbitrary concept of “doubling”. Your “mass” contains 14CO2. Are you arguing that it falls out faster because it is heavier? For some other reason? If not, it should represent the rest of the “mass”.
Gene Selkov says:
July 4, 2013 at 4:53 am
Thanks for the digitized data. I fit a single exponential to the C-14 curve from all locations using Excel Solver to determine the best estimate of the initial value in about July of 1963 (89% excess) and the residence time tau (14.4 years). Looking at the residuals, there was a hint of a possible much faster decay affecting a small fraction of the total, but I doubt that a two-exponential solution could be justified. As it is, the RMSE for the single exponential fit was just 3.2% so it really seems quite strongly to obey a single exponential decay. The R^2 for a linear fit to the logs was 98%. Excel file with multiple graphs available on Dropbox.
https://dl.dropboxusercontent.com/u/75831381/C-14%20decay%20from%20bomb%20testing.xlsx
Ferdinand Engelbeen says:
July 3, 2013 at 7:46 am
Indeed we have not much knowledge of ocean chemistry and biology, execept from deposits on the ocean floor and corals etc…
But we have quite good knowledge of the CO2 levels in the atmosphere as result of all the CO2 fluxes together: an increase or decrease of about 8 ppmv/K over the past millenium with a resolution of ~20 years, up to 800 kyears with a resolution of 560 years.
That shows very little variation over the past 1000 years, far from the over 100 ppmv/K we see over the past 50 years.
Thus whatever the cause of the increase, we may say with confidence that the current increase is unique over the past 800 kyears and not caused by any known natural source, including the oceans.
Following paper condradicts Ferdinands statement;
”Stomatal proxy record of Co2 concentrations from the last termination suggest an importan role for CO2 at climate change transitions” http://www.sciencedirect.com/science/article/pii/S0277379113000553
Margret Steinthorsdottir
According to this paper there has been large variation of CO2 concentration – more than 400 ppm.
Abstract
A new stomatal proxy-based record of CO2 concentrations ([CO2]), based on Betula nana (dwarf birch) leaves from the Hässeldala Port sedimentary sequence in south-eastern Sweden, is presented. The record is of high chronological resolution and spans most of Greenland Interstadial 1 (GI-1a to 1c, Allerød pollen zone), Greenland Stadial 1 (GS-1, Younger Dryas pollen zone) and the very beginning of the Holocene (Preboreal pollen zone). The record clearly demonstrates that i) [CO2] were significantly higher than usually reported for the Last Termination and ii) the overall pattern of CO2 evolution through the studied time period is fairly dynamic, with significant abrupt fluctuations in [CO2] when the climate moved from interstadial to stadial state and vice versa. A new loss-on-ignition chemical record (used here as a proxy for temperature) lends independent support to the Hässeldala Port [CO2] record. The large-amplitude fluctuations around the climate change transitions may indicate unstable climates and that “tipping-point” situations were involved in Last Termination climate evolution. The scenario presented here is in contrast to [CO2] records reconstructed from air bubbles trapped in ice, which indicate lower concentrations and a gradual, linear increase of [CO2] through time. The prevalent explanation for the main climate forcer during the Last Termination being ocean circulation patterns needs to re-examined, and a larger role for atmospheric [CO2] considered.
We can thus “say with confidence that the current increase is” NOT” unique”.
Ferdi: you clearly have a lot of detailed knowledge of the processes involved so you comments are interesting and appreciated. However, as I have said repeatedly just banging out some result without say where you the relationship from or where you get the numbers from does not help me see whether I agree with you or not. eg.
residence time = mass / inflows = mass / outflows = 800/150 = 5.33 years.
Am I supposed to recognise your 800 and 150 ? That makes no sense as it stands.
The above 14C decay rate is one of the results of this exchange rate, but is longer, because part of the exchange comes back in the following years from the ocean surface and vegetation decay (mainly leaves).
Good, so you are in fact saying that the 14y result is NOT the residence time. At least that is clear now. So we can forget your first confusing equation.
The decay rate of such an excess will be given by:
Tau = excess / (outflows – inflows) = 210 / 4 = 52.5 years
Again, what are these numbers?? Is that supposed to be the excess since pre-industrial? That’s more like 120 not 210 . Where does “4” come from?
It really would be much more use if you explained what you were doing.
Thanks.
Lance Wallace says: Looking at the residuals, there was a hint of a possible much faster decay affecting a small fraction of the total, but I doubt that a two-exponential solution could be justified.
That’s interesting. Would that be anything like the Bern model’s 1.186 years, if you fit it? That was the only but which did seem close to C14 curve and it would be nice if part of it could be reconciled since it is supposed to be derived from fitting empirical trace elements too.
I agree that a single decay model is probably sufficient but it would be interesting to know whether it matches.
Also 22y is not a mile away from 14y in view of many of the gross assumption involved and the non global nature of many of those tracer measurements. I would give more credibility to the C14 result as being well mixed and globally representative but the two may reconcilable.
That leaves the 179y and the 22% residual. The 22% is clearly wrong and does not merit further discussion. The 179y “decay” is probably and attempt to shoe-horn some multi-centennial variability into the same paradigm. In fact that may explain the 22% as well.
gymnosperm says:
July 4, 2013 at 1:52 pm
Ferdinand,
All you are doing is taking an arbitrary group of molecules and defining it as “mass” in relation to another arbitrary concept of “doubling”. Your “mass” contains 14CO2. Are you arguing that it falls out faster because it is heavier? For some other reason? If not, it should represent the rest of the “mass”.
There’s a significant difference between adding a pulse of a part per trillion tracer and a large pulse of CO2.
In the case of C14 it isn’t as readily adsorbed in the biosphere as C12 but it is adsorbed as otherwise carbon dating wouldn’t work. The major sink is therefore the ocean, unlike C12 the C14 is under-represented in the ocean however. The average age of C14 in the ocean surface is about 400 years as opposed to ~5 yrs in the atmosphere so you don’t see the two-way exchange that you get with CO2. Also a pulse of CO2 alters the net flow across the interphase whereas a pulse in C14 does not.
Mats says: Following paper condradicts Ferdinands statement;
”Stomatal proxy record of Co2 concentrations from the last termination suggest an importan role for CO2 at climate change transitions” http://www.sciencedirect.com/science/article/pii/S0277379113000553
Margret Steinthorsdottir
===
Thanks for the link. That backs up what I said earlier , the swing between the two very different climate states can not be taken as a basis for establishing ratio of T and CO2 that applies during the relative stability of an interglacial (even assuming the ice record were accurate).
If CO2 is supposed to be an important factor now it would have been many times more important when CO2 was around 180 ppmv (recalling the log relationship). The flip between two bistable states is typical of a positive feedback system. The fact that the system is bounded by stable states and does not continue with the run away reaction means that there is an even stronger negative f/b dominating. At least part of that controlling -ve f/b must be the reawakening biosphere.
Clearly such a transition tells us little about the current stable state
Yet another simplistic and erroneous assumption adopted without much critical thought by mainstream climatology.
Lance, w.r.t double exp. model. Introducing a second shorter term would presumably slightly lengthen the 14y time const. , that really would not be so far from the first two Bern model values given above.
33.8% will have a lifetime of 18.51 years
18.6% will have a lifetime of 1.186 years
How do the amplitudes come out if you do a double exp model?
Gene Selkov says:
July 4, 2013 at 10:55 am
Richard M asks: “Has anyone studied biological activity in ice?”
There is no active life in ice. Life relies on liquid water both inside and outside for structure maintenance and for the transport of materials. Under freezing conditions, chemical degradation is the only change. You can find spores and pollen in ice and even much larger organisms like fish and reptiles, some of which can thaw without damage, but there is no active life. No transport, no synthesis; only slow decay.
Not according to the links I provided. I assume you didn’t read them. I also got the feeling that this subject has had very little analysis done. The error bars looked to be huge and a lot of maybes in the text.
Mats says:
July 4, 2013 at 3:09 pm
Ferdinand Engelbeen says:
July 3, 2013 at 7:46 am
Indeed we have not much knowledge of ocean chemistry and biology, execept from deposits on the ocean floor and corals etc…
But we have quite good knowledge of the CO2 levels in the atmosphere as result of all the CO2 fluxes together: an increase or decrease of about 8 ppmv/K over the past millenium with a resolution of ~20 years, up to 800 kyears with a resolution of 560 years.
That shows very little variation over the past 1000 years, far from the over 100 ppmv/K we see over the past 50 years.
Thus whatever the cause of the increase, we may say with confidence that the current increase is unique over the past 800 kyears and not caused by any known natural source, including the oceans.
Following paper condradicts Ferdinands statement;
We can thus “say with confidence that the current increase is” NOT” unique”.
I don’t see where you get that from, the paper shows a transition nothing like the recent history, shows some fluctuations in the range of 180-340 ppm and no consistent change. The one spike that is close to our current value is based on 2 leaves and “may be an outlier”.
The linear feedback model leads to an exponential decay of an impulse change. Convolution of the annual emission data with such a function gives accumulation time series.
One property of such a model is that for a constant rate of increase the output is also the same constant rate of increase but with a time lag equal to the time constant of the decay function.
http://climategrog.wordpress.com/?attachment_id=411
approximating the p.pressure difference in uatm as the same number of ppmv and noting the lag of the linear response, the time delay corresponding to the pressure difference is :
p.press difference (ppmv) / rate of change (ppmv/year) = number of years lag
Taking the 7 microatmosphere “average” offset between ocean surface partial pressure and atm partial pressure of CO2 and attributing the current annual increase of 2ppm to emissions leads to a time constant of 3.5 years for a linearly proportional absorption model.
This clearly does not agree with anyone’s estimate of the reaction response.
The value of 14 years would imply a rate of increase of 0.5 ppmv per annum resulting from the absorption of emitted CO2. The remaining 1.5 ppmv/a must therefore be due to out-gassing.
Unless, the true decay function is nearer to 3.5 years than 14.
Unless, the true decay function is nearer to 3.5 years than 14… in which case the IPCC needs to downsize their estimations of how long CO2 emissions remain airborne by about two orders of magnitude.
Ferdi says: “The rate of outgassing only depends on two factors: the partial pressure difference water-air and the mixing speed of water and air, …Temperature influences the partial pressure of CO2 in seawater, thus there is a direct effect.”
Let’s play that back in slow motion. Temp changes partial pressure of CO2 in sea water. Rate of out-gassing depends the partial pressure difference.
So … rate of out-gassing ie d/dt(CO2), is proportional to temperature, which is exactly what I said in the first place.
Richard & Gene:
This deals with microbes in very salty water, so that it remains liquid in permafrost at -25 degrees C:
http://www.ncbi.nlm.nih.gov/pubmed/23389107
Phil. says:
July 4, 2013 at 6:37 pm
There’s a significant difference between adding a pulse of a part per trillion tracer and a large pulse of CO2.
Why? Rate constants are independent of species concentrations.
In the case of C14 it isn’t as readily adsorbed in the biosphere as C12 but it is adsorbed as otherwise carbon dating wouldn’t work.
Huh? The premise behind C14 dating is that the organism incorporates C14 into the tissue while alive. After death, exchange ceases. The rates of exchange of C12 and C14 differ only by a small kinetic isotope effect.
The major sink is therefore the ocean, unlike C12 the C14 is under-represented in the ocean however. The average age of C14 in the ocean surface is about 400 years as opposed to ~5 yrs in the atmosphere so you don’t see the two-way exchange that you get with CO2. Also a pulse of CO2 alters the net flow across the interphase whereas a pulse in C14 does not.
This last paragraph does not make any chemical sense. The flux across the boundary is governed by Fick’s first law of diffusion. Again, to a first approximation, nature does not distinguish between isotopes, which is why radiotracer studies can be used to probe the bulk system behavior.
Phil. says:
July 4, 2013 at 6:37 pm
In the case of C14 it isn’t as readily adsorbed in the biosphere as C12 but it is adsorbed as otherwise carbon dating wouldn’t work. The major sink is therefore the ocean, unlike C12 the C14 is under-represented in the ocean however. The average age of C14 in the ocean surface is about 400 years as opposed to ~5 yrs in the atmosphere so you don’t see the two-way exchange that you get with CO2.
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Do you have citations for all of this ? As a person who published several papers, in major journals, on highly complex secondary tritium isotope effects, I’d like to check out the primary literature here.
Also, I assume you meant absorbed, not adsorbed ?
ZP says:
July 4, 2013 at 10:23 pm
Phil. says:
July 4, 2013 at 6:37 pm
Again, to a first approximation, nature does not distinguish between isotopes, which is why radiotracer studies can be used to probe the bulk system behavior.
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Agreed in general ZP but, for the sake of accuracy, if the first step in the pathway, or any other important step is the RATE-DETERMINING step, then the isotope effects are measurable (but not huge).
If they’re not the rate-determining step, then they’re irrelevant.
Phil,
Refreshing to get to the crux of the issue which is how good a proxy is 14CO2 for the other isotopes? I doubt we can really answer that question. As you have pointed out it s not entirely biologically rejected, but it ought to be rejected even more than 13C if our notions are correct.
Your comment is a bit confusing regarding 14C in the oceans but I will take the greater age as indication of anomalous concentration. I once believed (and was corrected by Ferdinand) the oceans would be high in 12C. They are not. The oceans are repositories for the heavier isotopes.
Imagine that we wished to deliberately inject 14C as a tracer to find out if the increasing atmospheric CO2 were “ours” or not. What percentage of our combustion would we need to tag to be satisfied the results were not a statistical fluke?
I personally suspect a good bit of the increase is “ours” , but unlike Willis and Nick and Mosher and Ferdinand I don’t think we have any way to be certain of this. Nope, this here science ain’t settled either!