Over on the Hockey Schtick we have been alerted to a new paper which inadvertently offers a clue about the degree to which co2 levels are dependent on temperature, rather than the other way round, as the upside-down warmists claim. The last time this issue was discussed here at the talkshop, we made some real progress with the help of some excellent contributions from Richard Courtney, Bart, Roger Andrews, Stephen Wilde and others. That thread ended with a tentative conclusion from Roger A that the human contribution to the ~80ppm increase in airborne co2 since the 1950’s was between 25 and 60%, depending on the ‘residence time’ selected (5-15 years). Couple with the new lower estimates of sensitivity – the amount of warming expected for a doubling of co2 concentration – of around 1.6-2C this leaves cAGW (catastrophic anthropogenic global warming) pretty much dead in the water. The new paper may help constrain that estimate, so I’m putting it up for discussion again.
Figure 3 from:’Atmospheric verification of anthropogenic CO2 emission trends’
Roger J. Francey, Cathy M. Trudinger, Marcel van der Schoot, Rachel M. Law, Paul B. Krummel, Ray L. Langenfelds, L. Paul Steele, Colin E. Allison, Ann R. Stavert, Robert J. Andres & Christian Rödenbeck
Nature Climate Change 3, 520–524 (2013) doi:10.1038/nclimate1817
Michael at the Hockey Schtick writes:
New paper demonstrates temperature drives CO2 levels, not man-made CO2
Tallbloke's Talkshop 
I’d just add to Michael’s analysis that outgassing from volcagenic soils under increased sunshine hours due to diminished cloud cover in the 90’s is probably at least as big a factor as increased outgassing from the oceans, if not much bigger. SST doesn’t change as much as land surface temperatures.
https://tallbloke.wordpress.com/2012/04/18/uncertainty-the-origin-of-the-increase-in-atmospheric-co2/
There is considerable evidence that CO2 follows temperature on a daily basis (1-2hrs), on seasonal basis (maybe one month), on short term cycles (1 to 5 yrs – see for example http://www.biomind.de/realCO2/statements.htm) and in the long term cycles from ice cores (500 to 800 yrs)
Is there a way of proving CONCLUSIVELY that CO² follows temperature ? If yes than surely AGW is DEAD. We would be chaseing an unachievable goal.
“Is there a way of proving CONCLUSIVELY that CO² follows temperature ? If yes than surely AGW is DEAD. We would be chaseing an unachievable goal.”
Stephen,
Formally the answer is No, causality cannot ever be proved. [But that applies to all scientific endeavour.] You just try to rule out as many alternative explanations as you can be bothered to think of and test. At the simplest level, this is why kinetics experiments are so powerful: If A occurs before B, then A may, or may not, cause B. But B cannot cause A (unless it can travel backwards through time.)
As my thesis advisor used to tell the whole research group, “Remember: We’re a Kinetics Lab.”
In the kitchen, it is easy to set up controlled experiments where the rate of out-gassing of CO2 from a fizzy drink increases as you increase the temperature. Serious proponents of cAGW are mostly well aware of this, but are not keen to dwell on what they claim makes this problem go away when considered on a global scale. The “other” Shakun (&Marcott) paper in Nature last year was one such attempt.
“(The earlier) thread ended with a tentative conclusion from Roger A that the human contribution to the ~80ppm increase in airborne co2 since the 1950′s was between 25 and 60%, depending on the ‘residence time’ selected (5-15 years).”
Time for a recap. I based these conclusions on a simple mass-balance model which assumes that anthropogenic CO2 added to the atmosphere in any year will be absorbed in following years relative to a decay curve that can be defined either using the time constant (when the CO2 decays to 1/e of its original value) or the residence time (when the “average molecule” gets reabsorbed, which works out to 0.7 times the time constant if we assume that “average” means the the 50th in a chain of 100 molecules.)
The model results are summarized below. With a time constant of 50 years (35 year residence time) anthropogenic emissions explain effectively all of the 76 ppm increase in atmospheric CO2 between 1959 and 2010. With a time constant of 25 years (17.5 year residence time) they explain about two thirds of it and with a time constant of 10 years (7 year residence time) they explain about a third of it. But with time constants of more than 50 years they explain more CO2 than we had to begin with.
We can form only one reasonably firm conclusion from these results – that the very long CO2 atmospheric residence times assumed by the IPCC don’t fit observations, which means that the IPCC’s equilibrium climate sensitivity estimates will be too high, which I think is what the recent batch of 1.6 to 2.0C estimates are beginning to confirm. (These estimates, interestingly, are very similar to the IPCC’s transient climate sensitivity estimates shown in Table 8-2 of the AR5, which average 1.8C.)
http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch8s8-6-2-3.html
However, we can’t use the model to estimate how much of the recent CO2 increase was anthropogenic without an exact estimate of residence time. If residence times are in the 5-15 year range, as some claim, then indeed only a fraction of the recent CO2 increase was man-made. But where did the rest of the CO2 come from? The obvious source would be the oceans, but the amount of CO2 released from the oceans seems to explain only a fraction of the total. This is illustrated in the graph below, which compares monthly changes in ICOADS SST and Mauna Loa CO2, with CO2 advanced to allow for a 7 month global-average lag relative to SST. There’s generally (although not always) a direct correlation between changes in CO2 and changes in SST, but a regression fit gives an increase of only 3ppm CO2 for each degree C increase in SST.
So what do I think was the most likely cause of the recent atmospheric CO2 increase? Well, after having done all this work I have to admit the existence of uncertainty, but as an admirer of William of Ockham I still find this comparison as convincing as anything:
Thanks Roger, good summary. Remind us what the decaytime/residence time is for that last graph again please. Now, regarding this:
“The obvious source would be the oceans, but the amount of CO2 released from the oceans seems to explain only a fraction of the total.”
Did you read my comment earlier about volcagenic soils?
TB:
“Remind us what the decay time/residence time is for that last graph again please.”
It’s a straightforward plot of carbon emissions versus CO2. No smoke, mirrors or residence/decay times involved.
“Did you read my comment earlier about volca(no)genic soils?”
Yep. 🙂
A new paper by Henrik Svensmark finds a possible link between ocean temperature and atmospheric CO2 over the last 510 million years through “enhanced bioproductivity in oceans that are better fertilized in cold conditions.”
Evidence of nearby supernovae affecting life on Earth
Henrik Svensmark1.
1 National Space Institute, Technical University of Denmark,
Juliane Marie Vej 30, 2100 Copenhagen Ø, Denmark
22 April 2012
ABSTRACT
Observations of open star clusters in the solar neighborhood are used to calculate local supernova
(SN) rates for the past 510 million years (Myr). Peaks in the SN rates match passages
of the Sun through periods of locally increased cluster formation which could be caused by
spiral arms of the Galaxy. A statistical analysis indicates that the Solar System has experienced
many large short-term increases in the flux of Galactic cosmic rays (GCR) from nearby
supernovae. The hypothesis that a high GCR flux should coincide with cold conditions on
the Earth is borne out by comparing the general geological record of climate over the past
510 million years with the fluctuating local SN rates. Surprisingly a simple combination of
tectonics (long-term changes in sea level) and astrophysical activity (SN rates) largely accounts
for the observed variations in marine biodiversity over the past 510 Myr. An inverse
correspondence between SN rates and carbon dioxide (CO2) levels is discussed in terms of a
possible drawdown of CO2 by enhanced bioproductivity in oceans that are better fertilized in
cold conditions – a hypothesis that is not contradicted by data on the relative abundance of the
heavy isotope of carbon, 13C.
Key words: Astrobiology – Earth – supernovae: general – cosmic rays – open clusters and
associations: general – Galaxy: structure
Entire paper:
ftp://ftp2.space.dtu.dk/pub/Svensmark/MNRAS_Svensmark2012.pdf
I pose the question “Natural or Not?” about atmospheric CO2 in a document that covers much of this discussion. It can be found here: http://www.scribd.com/doc/129802522/Natural-or-Not
Jonathan, timely reminder, I meant to get around to posting on your study – apologies.
Roger A: Congrats, you found a correlation between two nearly straight lines. 😉
However, as the graph in the headline post shows, the rates of change of emissions and airborne fraction are in antiphase.
Gerry: Yes indeed, in the recent post here about improving fish stocks I mentioned increased food chain biota as a possible contributing factor. So I think we can expect that since fish stocks go in 60 year cycles along with the oceanic oscillations, co2 rate of change will be slowing and then possibly reversing over the next decade.
The Svensmark paper is a masterpiece, highly recommended. A great read.
Okay, back to basics. Here’s my theory: The 100 ppm increase in atmospheric CO2 since 1900 is explained by:
* Anthropogenic emissions of 1,400 gigatons CO2 since 1900
* 560 gigatons absorbed by carbon sinks such as oceans and vegetation
* 840 gigatons remains in the atmosphere.
And here’s what I understand from what others are saying to be the mainstream skeptic theory: The 100 ppm increase in atmospheric CO2 since 1900 is explained by:
* Anthropogenic emissions of 1,400 gigatons CO2 since 1900
* Most or all of which was absorbed by carbon sinks
* Which then re-emitted 840 gigatons of “natural” CO2 because of increased temperatures.
Do I have this right?
Brett Keane
@michael hart says:
April 30, 2013 at 2:36 pm
So, how do kinetics apply to the idea that lower frequency photons can affect higher frequency molecules? BK, NZ
Roger A: I think the correct understanding of this requires an appreciation of the vast size of the carbon cycle context in which the ‘fossil carbon’ is emitted. As usual the problem is ‘static thinking’ concerning sources and sinks. If Cardellini et al are correct, and 9Gigatonnes per year are being emitted from the decomposing volcagenic soils of central Italy alone, then the whole discussion changes. We are no longer talking about relatively static ‘net’ sources and sinks, plus anthropogenic emissions. We need to consider human emissions in the context of a natural carbon cycle in which both sources and sinks have increased during the warm period.
when you do that, it’s pretty obvious that increasing sources will outstrip increasing sinks when warming is occurring, because it takes time for additional vegetative biomass to ‘catch up’ with the increased availability of airborne co2.
The graph in the the headline post tells us there is no simple relationship between human emissions and increased airborne co2 in which ‘natural’ sources and sinks stay constant relative to each other. If there was, then the rates of increase would match. Therefore natural sources and sinks have been changing too, QED. We also know that sinks are bigger than sources, since the increase in the airborne fraction is only around half of human emissions. So the logical deductions are that:
1) Both sources and sinks have increased, but the increase in sources (including human emissions) outstripped the increase in sinks during the warming period
2) Since ~2000AD The sources are no longer increasing at a faster rate than the sinks, even though human emissions have accelerated
And the logical deduction from that is:
3) The changes in the ‘natural’ part of the carbon cycle are (considerably) bigger than the changes in the anthropogenic element.
When we add in the fact that rates of change of
emissionatmospheric co2 level closely follow changes in temperature we can further logically deduce that4) The majority of change in Co2 level has been caused by temperature rise (probably due to decreased cloud 1980-1998), not human emission (since changes in co2 lag changes in temperature at all timescales).
From that we can deduce that the atmospheric ‘decay’ (e-folding time) and residence times are much less than the figures the IPCC has plucked out of its arse, because otherwise, airborne co2 levels would by now be vastly higher than they are.
I tecently attended a lecture by Murry Salby in Oslo. He demonstrates very convincingly how CO2 variations follow temperature swings, out of phase by 90 degrees. Worth having a look at; http://notrickszone.com/2013/04/09/professor-murry-salby-to-callenge-global-warming-in-presentation-at-the-helmut-schmidt-university/
Tim,
Murray Salby will be lecturing in Cambridge soon too, but I won’t be able to attend. Thanks for the link to the write-up.
Brett Keane says:
May 1, 2013 at 5:06 am
Brett Keane
@michael hart says:
April 30, 2013 at 2:36 pm
So, how do kinetics apply to the idea that lower frequency photons can affect higher frequency molecules? BK, NZ
————————-
If I was making my post longer I would have more explicitly steered it away from objects travelling at the speed of light. In chemical reaction kinetics this can safely be ignored.
TB: Thanks for your response. However, to support the claim that the 100 ppm CO2 increase since 1900 was natural and not anthropogenic we need to come up with a plausible physical explanation for the disappearance of 1.4 trillion tons of anthropogenic CO2 from the atmosphere and its replacement with 840 gigatons of natural CO2, and I’m not sure there is one.
I also did some checking into Cardellini’s 9-gigaton volcanogenic CO2 flux estimate and found that it’s probably a typo. It should be megatons, not gigatons. Details supplied on request.
Roger Andrews,
I would put the problem differently. As I understand it, the currently adopted IPCC carbon-cycle model cannot adequately account where half of the anthropogenic CO2 has gone, and the error is growing all the time. The anthropogenic fluxes are small compared to the natural ones, which are themselves poorly understood or quantified. The burden of proof remains with the proponents of that model.
Put the details online here.
Probably? Who says? Do you think Cardellini would have stood up in front of the EGU with an order of magnitude error,given the enormity of the implication?
Some additional reading:
The WMO greenhouse gas bulletin for 2012
Click to access GHG_Bulletin_No.8_en.pdf
The top right diagram shows the disparity between CO2 emissions and observations. The declining red line showing how the carbon sinks are getting bigger and bigger.
The non-alarmist part of the text states:
“These sinks constitute the small net difference between large fluxes (~100 PgC per year) into and out of the atmosphere from the terrestrial biosphere and oceans. This small net difference varies with climate oscillations, such as El Niño and La Niña events. The ocean sink is less susceptible to human interference than the terrestrial biosphere.”
The data is taken from these two articles. Paywalled, unfortunately, but the first abstract (Ballantyne et al) describes it well.
http://www.nature.com/nature/journal/v488/n7409/full/nature11299.html
http://www.nature.com/nature/journal/v488/n7409/abs/488035a.html
It’s not just Economists who make unreasonable calculations based on things like assumed equilibrium conditions.
At pH~8.1-8.2 the ocean sinks appear to be some way from equilibrium pH that CO2 can achieve in pure water (rainwater pH~5.6, calculated to fall to 5.49 at 700ppm CO2 here: http://link.springer.com/article/10.1007%2Fs11270-008-9774-0#page-1 )
Solubility in seawater is much more than simple diffusion of the gas across the phase boundary into, and dissolution in, water, as per Henry’s law. At oceanic pH, most of the CO2 ends up as HCO3-, bicarbonate, and that’s partly why the ocean is such a huge sink. I would expect the rate of dissolution of CO2 to quite possibly be limited not only by CO2 diffusing into water, but by the rate at which it is converted into bicarbonate, which is about 7 powers of 10 (i.e. 10,000,000 times) SLOWER than a diffusion-controlled maximum reaction rate set by the Einstein-Smoluchowski limit. Note that while increased temperatures do drive the dynamic equilibrium towards the right hand side of the reaction:
(H+) + (HCO3-)=(H20) + (CO2)
-higher temperatures also increases the RATE of interconversion between the two species and hence the RATE at which equilibrium is approached from either side.
The practical upshot of this is that at higher temperatures, despite a slightly unfavourable shift in the equilibrium position, CO2 can dissolve FASTER in aqueous solutions that are not close to equilibrium. That is, the sink potentially becomes BIGGER because it never was at equilibrium.
Does this happen? It’d take a fair bit of time for slow-me to answer that. My guess is possibly not fast enough to make much difference in oceanic bodies of sterile water where the chemical reaction is not catalysed by living organisms. But they aren’t sterile. The oceans are teeming with very small life forms. And every life form, photosynthesising or respiring, makes carbonic anhydrase to catalyse the CO2-Bicarbonate exchange reaction. This is one of the so-called “perfect enzymes” because it speeds up the reaction to effectively the maximum rate set by diffusion. So life itself can speed up the rate of oceanic carbon sinks without actually capturing CO2 by photosynthesis.
Of course this might all be covered by the literature, if not the IPCC, but I’m not aware of it yet; much less whether this has been incorporated into carbon-isotope fluxes upon which the models live or die.
TB:
Cardellini details as per your request.
Cardellini et al. published two papers in 2011. The first was entitled “CO2 Fluxes from Earth Degassing in Italy”. It was authored by Cardellini, Chiodini, Frondini, Avino, Baldini and Donnini and presented at the EGU. The abstract includes the following statement:
“Quantitative estimates provided a regional CO2 flux of about 9 Gt/y affecting the region (62000 km2), an amount globally relevant, being 10% of the present-day global CO2 discharge from subaerial volcanoes.”
The second was entitled “Non-Volcanic release of CO2 in Italy: quantification, conceptual models and gas hazard”. The authors included Cardellini, Chiodini and Avino and the paper was presented at the AGU. The abstract includes the following statement:
“The total flux of CO2 in the area has been estimated in ~ 10 Mt/a which are released to the atmosphere through numerous dangerous gas emissions or by degassing spring waters (~ 10 % of the CO2 globally estimated to be released by the Earth through volcanic activity).”
There seems to be little doubt that the two papers are talking about the same area, but the first reports a CO2 flux of 9 gigatons/year and the second a flux of 10 megatons/year, a thousand times lower. Which is right? Based on the following lines of evidence it’s the megatons.
1. According to the first paper the CO2 flux in the study area represents 10% of the discharge from subaerial volcanoes, which is estimated at about 100 megatons/year, and 10% of this gives about 10 megatons a year, not 9 gigatons. According to the second paper it represents about 10% of the CO2 releases from all volcanoes, which are estimated at 200 or 300 megatons/year, and 10% of this gives 20-30 megatons/year. This is higher than the 10-megaton reported estimate but still orders of magnitude short of gigatons.
2. The phrase “globally relevant” in the first abstract is a giveaway. Nine gigatons/year amounts to about a third of total global fossil fuel CO2 emissions, and there’s no way this much natural CO2 seeping out of the rocks in an area that covers barely more than 0.1% of the Earth’s surface can be described as merely “globally relevant”. It would be potentially globally overwhelming, and the paper could hardly fail to point this out.
3. The map below (from Chiodini) shows contoured estimates of CO2 flux, in tons/day/sq km, in the 62,000 sq km study area. If we take an average of 0.5 tons/sq km/day, which looks about right, we get 365 x 0.5 = 182.5 tons/sq km/year, and multiplying this by 62,000 sq km gives 11.3 megatons/year for the area as a whole.
Based on these results I believe that the 9 gigatons/year in the first Cardellini paper is a typo, but feel free to pursue the question if you remain unconvinced.
I googled “cardellini 2011”, and clicked on images to see if there was more…
There was, and very nice too, but alas not about CO2 fluxes 🙂
michael hart:
Alas, or a lass? 😉
@michael hart says:
May 1, 2013 at 1:26 pm:
Thanks, Michael. Sigh, another shortcut to my fuller understanding shot down. But interesting all the same….BK
A delightful demonstration of more non-equilibrium thermodynamics of carbon dioxide in water: Now just over 1/3 of the way through the year and we’ve just had the first two days of serious sunshine in this part of Central England. (Might that be it for 2013?)
At midday I walked beside a slow stretch of the River Nene. Crossing a footbridge, I stopped and looked down. Only a few feet deep, the water looked markedly more opaque than two days ago. Like pieces of apple in a pint of particularly vicious Scrumpy, pieces of dead vegetation were slowly rising from the supersaturated depths, buoyed up with small bubbles of carbon dioxide. They accelerated towards the surface, each one producing an effervescent burst as they broke the surface.
It made me wonder, do any features of this resemble the El Nino/La Nina cycles in the pacific Ocean?
Roger Andrews says:
May 1, 2013 at 5:40 pm
“However, to support the claim that the 100 ppm CO2 increase since 1900 was natural and not anthropogenic we need to come up with a plausible physical explanation for the disappearance of 1.4 trillion tons of anthropogenic CO2 from the atmosphere and its replacement with 840 gigatons of natural CO2, and I’m not sure there is one.”
The oceans’ thermohaline circulation is a huge conveyor belt of CO2. It is constantly coming up in the tropics and outgassing to the atmosphere, and going back down again at the poles.
The rate at which it outgasses in the tropics is proportional to the temperature differential between the upwelling water and atmosphere. The rate at which it gets carried down at the poles is proportional to the temperature differential between the downwelling water and the atmosphere.
If those two rates are not in equilibirum, then CO2 will either accumulate or drain from the surface system.
Thus, we have an affine relationship between the rate of change of CO2 in the atmosphere and the global temperature with respect to a particular baseline:
dCO2/dt = k*(T – Teq)
CO2 = atmospheric concentration
k = coupling factor in ppm/degC/unit-of-time
T = temperature
Teq = equilibrium temperature
The coupling factor k is not necessarily constant, but apt to be effectively so over extended intervals. Such a relationship is what is seen in the records. It is especially well matched in the high accuracy satellite data. It appears to match Southern Hemisphere records best, lending credance to the hypothesis that this is largely an oceanic phenomenon, and due to upwelling CO2 rich waters which carried their high concentration down 100’s of years ago.
Integrating the rate of change over time leads directly to the observed atmospheric concentration. And, that concentration is almost entirely attributable to the temperature relationship, and not anthropogenic sources. If you could look into the future and provide me with temperature data for the next 10 years from one of the data sets referenced above, I could tell you quite accurately what the CO2 level would be at the end of that time, without needing any knowledge of anthropogenic inputs.
As for anthropogenic flow, it is first important to recognize that it is tiny compared to the natural fluxes. It is also mostly released over land, which has many active carbon sinks available. The argument is rather technical, but there is good reason to expect that the overall system acts something like the coupled set of equations below:
dCO2/dt = (CO2eq – CO2)/tau + H
dCO2eq/dt = k*(T – Teq)
CO2eq = equilibrium level of CO2 dictated by the ocean dynamics
tau = time constant
H = rate of change of airborne fraction of human inputs in ppm/unit-of-time
In these equations, if tau is short, then the contribution to CO2 from H will be drastically attenuated, but CO2 will track CO2eq closely. That, I believe, is basically what we see in the data.
Michael Hart: “It made me wonder, do any features of this resemble the El Nino/La Nina cycles in the pacific Ocean?”
This sounds somewhat similar:
“Effects of EL Nino/southern oscillation on the atmospheric content of carbon dioxide” by Keeling & Revelle, 1985.
adsabs.harvard.edu/full/1985Metic..20..437K
<a href=”http://adsabs.harvard.edu/full/1985Metic..20..437K” >link text here</a>
Sure that wasn’t oxygen?
Bart:
All kinds of good stuff in your comment. Thank you.
Time to consider, please?
In the meantime, here’s something to chew on. You say that “The rate at which (CO2) outgasses in the tropics is proportional to the temperature differential between the upwelling water and atmosphere.” Well, here’s a plot of the SST- air temperature differential in the tropical oceans since 1850. Unfortunately I can’t do a plot for the polar oceans because we don’t have any SST data there.
Roger A: I think the clue is in the title of the second paper. “Non-volcanic release” obviously doesn’t include release from volcanic sources!
Note that the second paper mentions the previous ‘estimate’ of the total flux, whereas the first paper talks about their own ‘QUANTITIVE MEASUREMENT’.
Roger Andrews says:
May 3, 2013 at 4:23 am
I suppose there could be different interpretations of the data you present. My thought would be that the upwelling water is definitely gaining heat from the surface waters, and releasing CO2 as it does so. So, if the surface waters are warming, then the upwelling waters should be releasing increasing amounts of CO2 to the atmosphere.
So, perhaps instead of saying “The rate at which (CO2) outgasses in the tropics is proportional to the temperature differential between the upwelling water and atmosphere”, I should have said “The rate at which (CO2) outgasses in the tropics is proportional to the temperature differential between the upwelling waters and surface waters.”
I think my basic idea is sound, but the narrative I offer has not been reviewed by many, probably not any with a sympathetic outlook, and could have holes, such as this one. Thank you for pointing it out.
The other side of the equation, of course, is how much CO2 is downwelling at the poles. It is the imbalance between the two which would tend to either accumulate or drain CO2 from the surface system.
Some other plots to consider. In the tropics, and Southern hemisphere SST.
Definitely dead vegetation coming from beyond the point of visibility, pulling/pushing a plume of supersaturated water, Tim. The rate, and nature, was also quite unlike methane.
Actually, few things will effervesce like CO2-water. If I could make oxygen in water fizz like champagne or coca-cola, I’d give you my second billion $$$ 🙂
Bart:
That graph wasn’t intended as a put-down – quite the opposite, in fact. It shows a gradual increase of about 1C in the tropical sea-air temperature differential over the last 150 years that more or less coincides with the increase in atmospheric CO2, and this gradual increase would presumably have caused increased ocean-air heat transfer at the Equator. Exactly how it would have affected ocean-air CO2 flux isn’t clear, but since CO2 solubility decreases with increasing temperature it should have caused the release of more CO2 into the atmosphere from the oceans, all other things being equal. So basically the graph is qualitatively consistent with a natural origin for both the warming and the atmospheric CO2.
The problem, however, lies in quantifying the effect of temperature on CO2. You summed the issue up succinctly with the equation:
dCO2/dt = k*(T – Teq)
CO2 = atmospheric concentration
k = coupling factor in ppm/degC/unit-of-time
T = temperature
Teq = equilibrium temperature
With the critical variable, of course, being k. Your plots of delta temperature against delta CO2 give k values high enough to explain pretty much all of the CO2 increase as a temperature-dependent effect, and I have plots which can be interpreted in the same way. The problem, however, is that these plots cover only the period since the Mauna Loa record began in 1958 (since 1979 for TLT) and the temperature-CO2 correlation exists only over this period. I’ve illustrated this on the following graph, which compares annual CO2 concentrations with HadCRUT4 going back to 1850, with the scales adjusted so the two plots line up visually over the period of recent warming:
A temperature-CO2 relationship is still visible in the tiny humps in the CO2 record that coincide with the 1987 and 1997-98 El Niños and in the larger hump that broadly coincides with the 1940 temperature peak, but these humps give k values that are far too small to explain the total CO2 increase. So my current best guess is that temperature changes cause only the wiggles in the CO2 plot. The long-term CO2 increase is caused by something else.
TB:
“Roger A: I think the clue is in the title of the second paper. “Non-volcanic release” obviously doesn’t include release from volcanic sources!
Note that the second paper mentions the previous ‘estimate’ of the total flux, whereas the first paper talks about their own ‘QUANTITIVE MEASUREMENT’.”
As it turns out these are actually papers three and four. Paper 1, published in 1999, cites CO2 flux from the study area at between 4×10^5 and 9×10^6 mol/year/sq km, equivalent to between 1 and 25 million tons of CO2/year over 62,000 sq km. Paper 2, published in 2004, states that “the total CO2 released … (2.1×10^11 mol/y) is globally significant, being 10% of the estimated present day total CO2 discharge from subaerial volcanoes of the Earth [Kerrick, 2001]”. Converting moles to tons gives 9.2 million tons CO2/year, a number which is indeed about 10% of Kerrick’s estimate of 88 to 110 million tons/year. Note also the similarity of the wording to the wording in the current papers.
These numbers do refer only to tectonically-induced degassing of carbonate sediments, but adding volcanic CO2 isn’t going to make that much difference. The highest CO2 flux number I’ve been able to find for Mt. Etna, arguably the most actively-degassing volcano in the world, is 50 million tons/year, and some of this is thought to come from degassing carbonates too.
Roger Andrews says:
May 3, 2013 at 3:47 pm
Roger – this is a superficial correlation, and the data set before 1958 is not verifiable.
It is a superficial correlation because it is not at all difficult to match two increasing time series affinely like this. If you have two trends, then they are completely affinely similar. If they both have same-sign moderate quadratic curvature, you can generally match them pretty well over a finite time interval simply by performing a least squares fit between the two series to derive the affine parameters which produce the best match.
It is nothing like the correlation you see in the plots, e.g., here, were every nook and cranny matches.
The data before 1958 are dodgy. If they weren’t, there would have been no point in setting up the MLO facility in the first place. There are no independent superior, or even comparable, measurements with which to verify the estimates from ice cores. It is all founded on assumptions about how the gases stored in the ice behave.
I was challenged on this point some time ago by Ferdinand Englebeen, who insisted that I had to accept the pre-1958 measurements as gospel truth. He pointed out that extending the relationship back before 1958 resulted in a hindcast estimate of CO2 in 1900 that was too low.
To be clear, I do not have to accept the inviolability of the data before 1958. As I said, there are no means of verification. However, in order to render the point moot, I brought up the fact that the parameters are potentially variable – e.g., we could currently be experiencing a bubble of higher CO2 density upwelling waters. There could have been a regime change, resulting in a change in the effective parameters at some point in the history. So, I ran the model again, inserting a step change into them in about 1945 to obtain this plot, showing that the formulation is flexible enough to cover such events.
But, all this is academic. The bottom line is that, since 1958, using the best, most modern, most precise measurements available, the CO2 in the atmosphere has tracked the relationship
dCO2/dt = k*(T – Teq)
with exquisite precision given the quality of the data. That is the period of the greatest growth in CO2, and the relationship shows that, that growth did not come about due to human inputs.
“So my current best guess is that temperature changes cause only the wiggles in the CO2 plot. The long-term CO2 increase is caused by something else.”
The amazing thing about this plot is that, in order to fit the variation between the series, you also end up fitting the trend. They are consistent with one another. If you decrease the scaling so that you can add in a portion of the trend from anthropogenic forcing, then the variation no longer matches.
Ferdinand continually insisted that the temperature based trend was somehow filtered out by natural systems, and the anthropogenic trend was what determined the long term behavior. But, this action would necessarily leave telltale phase dispersion so that various frequency components of the time series would have different delays, and you would not get such a broad spectrum match as we do.
It also runs contrary to Occam’s Razor. Which is more likely? That there is some exotic process which takes out the natural temperature related trend, which precisely matches the overall trend on its own, and substitutes in the human trend without any discernible phase distortion? Or, that temperature is simply responsible for the essentially the entire ball of wax, and human inputs are rapidly sequestered?
To me, the final confirmation that temperature is driving the CO2 level was the realization of the continuous transport model I have described above. It leads from first principles to a relationship of the type
dCO2/dt = k*(T – Teq)
which is PRECISELY what is observed in the historical record since at least 1958.
Ferdinand would insist that there is a definite sensitivity of some small number of ppm/degC, and this small number invalidates the hypothesis that the CO2 is coming from the oceans. But, that is a static analysis, and it is not applicable to a continuous transport system of this kind. Here, the sensitivity number inherently MUST be in units of ppm/degC/unit-of-time, and the input can cause the output CO2 level to grow without bound as long as conditions allowing it to do so persist.
Bart:
“(T)his is a superficial correlation”. If you’re referring to the graph I posted above then the idea was to show that over the longer-term there is NO obvious correlation other than the minor wiggles and humps in the CO2 record that coincide with shorter-term temperature excursions.
“The (CO2) data before 1958 are dodgy.” “There are no independent …. measurements with which to verify the estimates from ice cores.” The data I use are from the Scripps atmospheric CO2 records after 1958 and from the Law Dome ice core records before then. Over the 20-year period of overlap between 1958 and 1978 the Scripps and Law Dome records match each other very closely and the 280-310 ppm Law Dome values before 1958 are backed up by CO2 values measured by the Scandinavian sampling network (Fonselius, 1956).
The CO2 in the atmosphere since 1958 “has tracked the relationship dCO2/dt = k*(T – Teq) with exquisite precision.” I’ve already acknowledged that the results can be interpreted this way over this period, but you have a problem when the exquisite precision falls apart before 1958, and not because of bad data.
Stephen Richards says:
April 30, 2013 at 1:16 pm
Is there a way of proving CONCLUSIVELY that CO² follows temperature ? If yes than surely AGW is DEAD. We would be chaseing an unachievable goal.
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wrong.
you would have to show that C02 increases dont lead to temperature increases.
It’s well known and predicted that increases in c02 will follow a temperature increase.
Hansen actually made this prediction before the effect was found in paleo data.
C02 is a GHG. GHGs raise the ERL. When the ERL is raised the planet re radiates from
a higher cooler region and the surface cools less rapidly as a result. In short, C02 causes warming.
IN ADDITION, in a warmer world you will get more C02 outgassing.
Put another way.. you learn nothing by looking at leads and lags. but you can waste your time trying
Roger Andrews says:
May 3, 2013 at 10:15 pm
“Over the 20-year period of overlap between 1958 and 1978 the Scripps and Law Dome records match each other very closely and the 280-310 ppm Law Dome values before 1958 are backed up by CO2 values measured by the Scandinavian sampling network (Fonselius, 1956). “
First, define “very closely”.
Then, you will have only verified the measurements from 1958 to 1978 between Scripps and Law Dome. Time is the critical variable. In the morning after shaving, my face is as smooth as a young boy’s for perhaps a couple of hours. That does not mean our faces will look anything alike at 5:00 PM. Extrapolation beyond the confines of the data is always hazardous.
You will have to fill me in on the Scandinavian sampling network if I have it wrong, but the reference I looked up says it had only “just begun” in reference to the year 1955.
“…but you have a problem when the exquisite precision falls apart before 1958, and not because of bad data.”
As I have stated:
A) It doesn’t fall apart. If the data prior to 1958 are genuine, the coefficients may simply have shifted. Indeed, it is frankly surprising to me that they appear to be fairly stable since 1958.
B) The question is moot. In the modern era, the relationship holds. That is the era in which the lion’s share of the rise in CO2 was recorded.
I have given you a first principles argument for how the data should look, and they do look that way. The match is over the period of the most reliable, most modern measurements. It is pretty obvious that temperature is calling the shots.
But, if you don’t agree, you don’t agree. However, I suggest you keep an eye on the dCO2/dt to temperature relationship as temperatures accelerate their fall in the next decade, in accordance with the ~60 year cycle starkly evident in the data. As the temperatures fall, the rate of CO2 increase will fall (it has already flatlined along with temperature in the last decade). Emissions will continue to accelerate, and the increasing divergence between them and the measurements will become unequivocal at some point.
Bart:
“If you don’t agree, you don’t agree”. Well, I try to be objective about these things, and as Tallbloke can confirm from private email correspondence I spent a lot of off-blog time last year trying to demonstrate that my initial assessment – that the CO2 increase was anthropogenic – was wrong and that it was in fact natural, but I couldn’t come up with any results that I found convincing enough to make me change my opinion.
However, I did manage to convince myself that the question could not be solved analytically – too few equations, too many unknowns. So I still have to go with what is basically my gut feeling. (I will of course keep an eye on what happens to CO2 and temperatures in the next decade, but I’m getting up there and can’t guarantee that I will still be around in ten years’ time.)
But let me now raise another issue. You interpret the temperature-CO2 relationship after 1958 to mean that the warming generated the CO2. The IPCC uses the same relationship to claim that the the CO2 generated the warming. It seems to me that causality can work in both directions here, so why is your interpretation right and the IPCC’s wrong?
And if you believe, as I do, that CO2 has little or no impact on temperature, does it even matter what caused the increase?
Roger A: It seems to me that causality can work in both directions here, so why is your interpretation right and the IPCC’s wrong? And if you believe, as I do, that CO2 has little or no impact on temperature
Well if co2 has little or no impact on temperature, then that’s one direction causality isn’t working in. 🙂
Roger Andrews says:
May 4, 2013 at 4:21 am
“It seems to me that causality can work in both directions here, so why is your interpretation right and the IPCC’s wrong?”
The arrow of causality is inherent in the differential equation
dCO2dt = k*(T – Teq)
If CO2 were driving temperature, then the temperature would be responding not to the level of CO2, but to its rate of change. You could pump 10,000 ppm into the atmosphere but, once you stopped pumping, T would return to Teq, regardless of the level in the atmosphere.
This is clearly an absurd outcome, hence we must conclude that temperature is driving CO2, and not the reverse.
“And if you believe, as I do, that CO2 has little or no impact on temperature, does it even matter what caused the increase?”
Well, it does if we really want to understand the system. And, if we want to drive home the lessons from the impending debacle as the AGW brouhaha crashes to its ignominious end.
The scientific method has taken a real beating in the overheated rush to judgment. The time is nearly upon us to reassert that “intuitively obvious” is not a valid answer to any scientific question. Not for an undergraduate taking a test, not for a graduate student expounding a formal proof, and certainly not for professionals in the field investigating matters upon which hang the lives of billions of people around the globe.
The annual (sesonal) temperature (SST) cycle drives the annual atmospheric CO2 cycle. After one annual temperature cycle is over, the atmospheric CO2 doesn’t necessarily returns to its starting point – that’s the annual change in atmospheric CO2. The upcoming cooling will reduce the annual increase in atmospheric CO2.
Thanks, Edim.
Plenty of people have no problem with the idea that internal variability prevents temperatures returning to their starting point at the end of the annual cycle… But what makes so many (apparently) think that CO2 will do? It’s a “Homer Simpson moment” in-the-making.
Do you have any other links to go with that graph?
Stephen Richards says:
April 30, 2013 at 1:16 pm
“Is there a way of proving CONCLUSIVELY that CO² follows temperature ? If yes than surely AGW is DEAD.”
It has been dead for quite a while! It is starting to look a lot like the fish in Hemingway’s “Old Man and the Sea”.
While “michael hart” is correct when he says “causality cannot be proved”, “non-causality” can be proved.
Einstein explained this neatly when he said:
“No amount of experimentation can ever prove me right; a single experiment can prove me wrong.”
This post is yet another stake through the heart of the already dead Arrhenius theory that says:
“The selective absorption of the atmosphere is……………..not exerted by the chief mass of the air, but in a high degree by aqueous vapor and carbonic acid, which are present in the air in small quantities.”
Real scientists understand that it only takes one experiment to falsify a hypothesis. Sadly the CAGW zealots don’t care what the science says, so in September the corrupt and secretive IPCC will publish Assessment Report #5 (AR5). Expect the Shakun study to get top billing in the WG1 “Paleo” section (Chapter 5), while dozens of better studies covering 800,000 years will be dismissed with one liners. This is just “Politics as Usual”.
It won’t matter because even the CAGW faithful know that the ice cores show temperature driving CO2 rather than the reverse. Not that they will admit it in public:
http://diggingintheclay.wordpress.com/2013/05/04/the-dog-that-did-not-bark/
The orthodox creed of the CAGW faithful since the dreadful (to them) revelation that CO2 lags temperature formulated by Jeff Severinghaus who worked on EPICA and Greenland ice cores:
http://www.realclimate.org/index.php/archives/2007/04/the-lag-between-temp-and-co2/
The Severinghaus’ idea essentially concedes that CO2 can at most account for 10% of the temperature changes associated with glaciation cycles. That 10% number assumes that all of the “Global Warming” since 1850 was caused by CO2, an idea that looks crazier with each year that passes given Mother Nature’s recent tendency to mock the Keeling curve.
A short note, as I was not aware of this discussion…
I had several discussions in the past with Bart on the same subject. The main problem is that he uses one time constant that should fit all changes, while in nature several mechanisms with different time constants are at work.
– the oceans surface changes its total carbon content (CO2 + _bi_carbonates) with 10% for a 100% change in CO2 of the atmosphere, because of the Revelle factor. The time constant there is 1-3 years. Similar for fast changes in vegetation. That is the cause of the fast response of the CO2 rate of change to temperature (at 16 ppmv/°C).
– the deep oceans exchanges are much slower with a time constant of ~50 years. Similar for the long term uptake of carbon in vegetation (roots, peat, coal). That is the cause of the slow rise in uptake capacity, directly related to the difference between current CO2 level and equilibrium setpoint level, the latter temperature related. But as we are already 100 ppmv above equilibrium, any temperature change has less influence.
Thus at least two quite different time constants are at work: one fast, but limited in capacity, the other slower, but far less limited in capacity (deep oceans), if not unlimited (vegetation).
Further, any non-human origin of the increase I heard of violates one or more observations, including the oceans: these have a too high 13C/12C ratio, thus any substantial release of the oceans would increase the 13C/12C ratio of the atmospheric CO2, but we see a decrease, both in the atmosphere and the ocean’s surface, far beyond natural variability:
See further:
http://www.ferdinand-engelbeen.be/klimaat/co2_measurements.html#The_mass_balance
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