Carbon cycle questions

by Judith Curry

I just finished listening to Murry Salby’s podcast on Climate Change and Carbon.  Wow.

The abstract for his talk is here:


Chair of Climate, Macquarie University

Atmospheric Science, Climate Change and Carbon – Some Facts

Carbon dioxide is emitted by human activities as well as a host of natural processes. The satellite record, in concert with instrumental observations, is now long enough to have collected a population of climate perturbations, wherein the Earth-atmosphere system was disturbed from equilibrium. Introduced naturally, those perturbations reveal that net global emission of CO2 (combined from all sources, human and natural) is controlled by properties of the general circulation – properties internal to the climate system that regulate emission from natural sources. The strong dependence on internal properties indicates that emission of CO2 from natural sources, which accounts for 96 per cent of its overall emission, plays a major role in observed changes of CO2Independent of human emission, this contribution to atmospheric carbon dioxide is only marginally predictable and not controllable.

Professor Murry Salby holds the Climate Chair at Macquarie University and has had a  lengthy career as a world-recognised researcher and academic in the field of Atmospheric Physics. He has held positions at leading research institutions, including the US National Center for Atmospheric Research, Princeton University, and the University of Colorado, with invited professorships at universities in Europe and Asia. At Macquarie University, Professor Salby uses satellite data and supercomputing to explore issues surrounding changes of global climate and climate variability over Australia. Professor Salby is the author of Fundamentals of Atmospheric Physics, and Physics of the Atmosphere and Climate due out in 2011. Professor Salby’s latest research makes a timely and highly-relevant contribution to the current discourse on climate.

The podcast for his talk is here.  Unfortunately there is no video so you can’t see his graphs.  But the talk is very lucid, you can certainly get the point.  The entire podcast is an hour, with his formal presentation about a half hour, and questions for the remaining half hour.

This talk was given in June at the IUGG meeting in Melbourne Australia, and apparently created quite a stir.    A journal paper is in press, expected to be published in about 6 months.  Some of the results will be in his forthcoming book Physics of the Atmosphere and Climate that will be available Sept 30.

Andrew Bolt has some reactions in the Herald Sun:

Salby’s argument is that the usual evidence given for the rise in CO2 being man-made is mistaken. It’s usually taken to be the fact that as carbon dioxide concentrations in the atmosphere increase, the 1 per cent of CO2 that’s the heavier carbon isotope ratio c13 declines in proportion. Plants, which produced our coal and oil, prefer the lighter c12 isotope. Hence, it must be our gasses that caused this relative decline.

But that conclusion holds true only if there are no other sources of c12 increases which are not human caused. Salby says there are – the huge increases in carbon dioxide concentrations caused by such things as spells of warming and El Ninos, which cause concentration levels to increase independently of human emissions. He suggests that its warmth which tends to produce more CO2, rather than vice versa – which, incidentally is the story of the past recoveries from ice ages.

The Earth’s carbon cycle is not a topic on which I have any expertise.  A good overview article is provided by NASA’s earthobservatory.

Climate models have begun to include an interactive carbon cycle in the CMIP5 simulations.  NASA has been trying to launch a satellite to measure global carbon, an effort which remains troubled and plagued by continuing delays.

JC comments:  If Salby’s analysis holds up, this could revolutionize AGW science.  Salby and I were both at the University of Colorado-Boulder in the 1990’s, but I don’t know him well personally.  He is the author of a popular introductory graduate text Fundamentals of Atmospheric Physics.  He is an excellent lecturer and teacher, which comes across in his podcast.  He has the reputation of a thorough and careful researcher.  While all this is frustratingly preliminary without publication, slides, etc., it is sufficiently important that we should start talking about these issues.  I’ll close with this text from Bolt’s article:

He said he had an “involuntary gag reflex” whenever someone said the “science was settled”.

“Anyone who thinks the science of this complex thing is settled is in Fantasia.” 

Moderation note:  this is a technical thread, comments will be moderated for relevance.

1,129 responses to “Carbon cycle questions

  1. Thank you, thank you, Professor Curry, for another moment of truth.

    Propaganda artists have manipulated and used good citizens of the once “Free West” by the same bag of “political correct” consensus opinions that once openly controlled the other half of the globe.

    With kind regards,
    Oliver K. Manuel

    • “another moment of truth.”

      Thank you, Oliver, for illustrating the mis-named “skeptics” blind, unquestioning faith in the truth of whatever they want to believe.

      No paper, no slides, no evidence . . . but that’s not a problem for a true believer.

      • Only a prejudiced man would color an entire heterogeneous group by the writings of just one data point. Perhaps you are the one trying to see what you just want to see.

      • Robert, have you actually listened to the podcast?

        It’s frustrating that the slides Salby uses can’t be seen, but there is no lack of science in the presentation. I’m at ~18:40 and counting.

        I’d suggest you listen before commenting.

      • Until we can see Selby’s slides, Tom V. Segalstad presented similar material from earlier sources:
        Carbon isotope mass balance modelling of atmospheric vs. oceanic CO2
        Tom V. Segalstad, Heartland Institute ICCC 2009

        Note: Proof from isotopic mass balance slide 12/30

        The calculations confirm that maximum 4% (14 GT C) of the air CO2 has anthropogenic origin; 96% is indistinguishable from non-fossil-fuel (natural marine and juvenile) sources. Air CO2 lifetime is ~5 years.

        Note Slide 15/30

        “The upper 200m has enough Ca to bind ALL remaining fossil fuel CO2 as calcium carbonate”

        CO2 & Volcanism (slide 17/30

        Mikhail I. Budyko has shown good correlation between emissions of CO2 through periodes of extensive volcanism and deposition of marine carbonate rocks during the Earth’s last ~600 million years.

        Under equilibrium Slide 24/30:
        <blockquote This means that there will be about 50 times more CO2 dissolved in water than contained in the free air above.
        Ocean buffers Slide 28/30

        This anorthite feldspar ↔ kaolinite buffer has a buffer capacity 1000 times larger than the ocean’s carbonate buffer.

        Presentation also at
        Interview Segalstad on CO2 lifetime

      • Thanks, just spotted your response – should keep me busy.

      • Selby details the cause/consequence issue raised by Spencer. See links below to similar posts by Roy Spencer on Ocean driving CO2; and The C13/C12 Isotope Ratio

      • I do not think this study is really anything new. A study from early 2010 reported very similar information.

        In truth we do not really know what percentage of total atmospheric CO2 is due to humans because we have no reliable, accurate way to determine this information. The best we can do is to estimate how much CO2 humans are putting into the atmosphere and then see if there is a good correlation to the rate that overall CO2 levels are changing. It appears that there is not a great relationship as far as I can tell, but if we use common sense we can tell that people are putting a considerable amount of CO2 into the atmosphere and total CO2 is rising, so it would seem logical that humans are greatly contributing to the overall rise.

      • er then you havent listened to the podcast. Its worth the time. Educate yourself. then step to the keyboard.

      • I have listened to the podcast. Have you reviewed the math and the margins of error in the calculations?

      • think about this sentence:
        “so it would seem logical that humans are greatly contributing to the overall rise.”
        Think about the word greatly.
        Doubtless the amount is higher than it would be without our contribution.
        But that’s not the question and not your statement.
        Think about this:
        “But that conclusion holds true only if there are no other sources of c12 increases which are not human caused. Salby says there are – the huge increases in carbon dioxide concentrations caused by such things as spells of warming and El Ninos, which cause concentration levels to increase independently of human emissions.”

        So what may seem “logical” to you, that we are contributing “greatly” depends upon a uncertain assumption “only if there are no other sources of c12 increases which are not human caused”

        So, it would seem there are questions about the assumption that drive your “logical” conclusion. The one who needs to produce error bars is the person making the logical leap. Not the person questioning the logical leap.

        we’ll see if his work holds up. But i’d pause before making any “logical” leaps.

      • I notice that as well. It seems to those who “want” to believe the increase in CO2 is due to man they must assume there are no natural increases that could cause it.

        Man contributes 4% of the carbon. That means 96% comes from natural sources. It is easy to see that you don’t need a great increase from natural sources to totally overwhelm any contribution man may be making (a 4.2% natural increase equals the total contribution of man while a 4.2% increase in mankind’s contribution would increase the total by less than 2 tenths of a percent) .

      • Steve

        In this case I believe I chose my wording appropriately and that your comment was “misguided”.

        I wrote that human CO2 emissions “greatly” impacted total atmospheric CO2 levels. The term does not denote a specific percentage. It would seem inappropriate to claim that the human contribution is “insignificant”. The conclusion is not dependent to their being no other sources for C12 in the atmosphere as you wrote. If you think about that it is a bit silly. What you refer to matters about measuring the source of the CO2 and not its impact on the climate.

      • David Bailey

        Surely the most salient point is that annual CO2 increases varied from nearly zero to twice the average rate (the slides would be really useful – I wonder if Judith could obtain them!) depending on external factors such as El Niño events. Since industrial CO2 is obviously produced steadily, it doesn’t seem to be a big contributor.

      • Fail to see how “greatly” is obvious but not “insignificantly” other than a IMO

      • Julian Flood

        An atmospheric light C signal can be caused in two ways: an increased input of 12C or a reduced pulldown of 13C. The latter can be easily caused by ecosystem alterations, tipping them from C3 to C4/CAM metabolism. An example would be an increase of dissolved silica in the oceans, giving C4 diatoms the advantage over C3 calcareous phytoplankton. The difficulty here is that diatoms do not export as much carbon to the deep ocean and they would leave an increasing proportion of light C and more C in total… hang on, are we onto something here?


      • There are two main sources of the 13C/12C decrease: fossil fuel burning and decay in the biosphere. It is near impossible to make a differentiation between the two based on the 13C/12C ratio, as Salby says, but there are two differences: recent carbon contains 14C in ratio with what was absorbed during growth, but old carbon is 14C free. And the oxygen balance can give information if the biosphere is a net source or sink for CO2.

        The first was clear: 14C ratios declined in the pre-nuclear tests, so that carbon dating needed correction tables.

        The second is also clear: If the oxygen use from fossil fuel burning is calculated, one does find a deficit in the oxygen trend: less oxygen is used than calculated. Thus extra oxygen is produced by the biosphere, there is more CO2 uptake than CO2 release and by preference more 12CO2, increasing the 13C/12C ratio in the atmosphere. This excludes the biosphere as source of the increase. See:

        Similarly the oceans are excluded, as the 13C/12C ratio of the oceans is too high, thus any substantial release of ocean CO2 would increase the 13C/12C ratio, but we see a decrease, as well as in the atmosphere as in the ocean surface layer:

        With some literature search, Salby would have known that…

      • The 14 C calculations are even more discredited….as you know already.

        The errors in the measurements and calculations totally discredit the oxygen argument.

        Usually you fall back on the Vostok ice core record as your gold standard of how much CO2 increase the biosphere is capable of; not much of an argument but you stuck to it through thick and thin. Now Salby knocks that plank away, you are reduced to even weaker arguments.

        Now clearly you have made your mind up and that’s it. The rest of us continue to say that the idea of an overflowing bathtub representing mans 3% overloading the system was always ridiculous from day one.

      • Ferdinand Engelbeen

        JamesG, can you give some references to the literature where the errors in the oxygen measurement are that large that they invalidate that the biosphere is a net sink for CO2?

        Further, everybody says that the earth is greening, as also seen by satellite observations, is that not true?

      • What is important about the study is not simply the material, but also the author. Science has historically been slow to accept new findings based on a single paper. As more and more scientists study the question and release their findings the mainstream position shifts. Like CO2 and temperature, there is a lag. 20 years after ulcers were shown to be caused by bacteria, surveys showed 80% of all doctors still believed they were caused by stress.

      • Judith – I’m curious as to what metric you’re using for determining “technical relevance.”

      • If it annoys you it is relevant. If you approve, it is left-wing drivel.

      • One might be tempted to think that Judith’s criteria match yours.

        What’s interesting is that she hasn’t clarified whether they do or not.

      • Well Joshua, that’s science. Judith is letting science do its thing.

      • Joshua, a blog with a couple hundred comments a day is likely very time consuming. Most blogs this size will not scrutinize every word. Don’t be so self-centred.

      • Joshua

        She doesn’t need to clarify anything to you. It’s her blog and her house. You are the visitor here. Her rules apply. If you don’t like, you’re free to leave.

      • Venter –

        I never thought that she “need[s]” to clarify anything. It’s interesting to me that anyone could even interpret my comment as saying that she “needs” to do something. Of course her rules apply. I’m simply asking that she clarify the rules. As it stand currently, she says that she’s monitoring posts for technical relevance and then allows attack comments from the likes of hunter and Bruce (well, and Robert) that are mostly unrelated to the topic at hand.

        Perhaps when you’re a very entitled person, you think that others are saying that someone “needs” to do something when they are only making requests?

      • Joshua –
        Perhaps when you’re a very entitled person, you think that others are saying that someone “needs” to do something when they are only making requests?

        Making a request is one thing. Making repeated requests is a demand. Sometimes called “badgering”.

      • Does your Mommy know you are here acting like a crybaby?

      • CO2 goes up and down as a function of Ocean Water Temperature and not the other way. This is simple physics. Dr. Salby has a good understanding of simple basic physics. Open a hot and a cold carbonated drink and observe the extreme difference. The huge amount of Water and ice and water vapor and clouds regulate the temperature of earth. The tiny amount of CO2 goes in and out of the water as temperature goes down and up. The tiny amount of CO2 does likely have a correspondingly tiny influence on temperature. The trace of CO2 has a huge influence on how green things grow. We need and like green things. The more CO2 we can get, the better life on earth will be.

      • Many years ago, there was much more CO2 in the Atmosphere and Earth Temperature was not a lot warmer than now. Earth took a lot of the CO2 out of the atmosphere and stored it for us in Carbon Based Fuels. She almost took too much. We are close to the low level at which green things can;t grow and very far from a high level that is dangerous. The Space Station CO2 limit and The Submarine CO2 limit are in the Thousands. Order of magnitude above what we have now. Earth knows how to regulate CO2. Let Earth do her job as she has always done.

    • Anyone want to discuss what the pal reviewed literature says about all this?

      start here, pick a paper, any paper.

    • Thank you, Oliver, for reminding us the probity of Baron VonMonkhofen’s reaction:

      Wow. Wohohow!

      Wait. Are we in 2011?

    • Found that ‘iron sun’ yet?

  2. Dr Curry,
    Thanks for putting this up. It is such a shame that it’s not a video- i’d love to see the graphs; it’s very difficult to make a full evaluation of his talk without the relevant graphics.

    That said however; this mirrors some work i saw about a year ago that called into question the assuption that only C12 was natural- when in fact some (and in fact a significant proportion) of plants naturally produce (and release c13. I’ll try to dig the article out when i get home.

    I think this talk most importantly tackles one of the biggest (and in my opinion most important) assumptions of the cAGW theory- the complete reduction of natural variation and influence on global temperature and co2 levels.

    If this work holds up, i think it presents a REAL problem for the cAGW theory. This needs looking at quite thoroughly, by both sides.

    • munkey,

      I guess Dr. Curry should have the slides but has no permission to publish it here. It will probably behind a paywall soon or buy a copy of his book in about one months’ time. Something legitimate for the hard work and non-funded by the big oil, the big coal and remotely from the Government fund to skeptics. But I am such a low lying greedy man getting it without paying.

  3. That the CO2 increase might not be due to human emissions is something I have pointed out here on several occasions. This is a fascinating issue that has been perking along under the radar for a long time. The problems with C12/13 ratios are not new. Plus there are interesting arguments for the mechanism whereby CO2 levels are driven by temperature changes. But Salby’s heavyweight status changes the game.

    • I have been saying that for years. I agree with you.

      For sure under the radar. There is no CO2 category on this blog. And CO2 is the devil.

      There’s evidence (no links, sorry) that the atmospheric CO2 rate of change (time derivative – dCO2/dt) is correlating very well with the global temperature. The CO2 lags the temperature.

  4. “If this work holds up, i think it presents a REAL problem for the cAGW theory. ”

    If there were such a thing as “cAGW theory,” it might be a problem. But of course you cannot point to any evidence that such a theory exists. It’s just part of the pseudoskeptical mythology.

    I doubt very much Salby’s work will be a problem for any actual scientific theory. While it would be interesting if the isotopic ratio were not the reliable fingerprint of anthropogenic emissions it has been thought to be, that is only one of many independent lines of evidence that the current rise in CO2 concentrations is caused by people. One can start with the fact that we are watching ourselves release the stuff by the gigaton.

    I guess we’ll see what Salby has when he publishes.

    • I tend to agree that it is difficult to argue that we aren’t cointributing to the co2 in the atmosphere. The real question, from my rather primitive understanding of the research, is what will this do to the calculated residency times.

      • It’s the proportion of the contribution and the significance that is of issue here. NO ones denying we’re not releasing co2. No one sane anyway.

      • simon abingdon

        “NO ones denying we’re not releasing co2.” On the contrary, no-one’s denying we are”

      • OOPS!!! that is of course what i meant! mea culpa!

    • Hang on hang on. What?!?

      with cAGW i am referring to catastrophic anthropogenic warming- i.e. the position touted by the IPCC et al that the change in climate we are seeing is;
      a) dangerous,
      b) man-made
      c) linked to human Co2 and finally
      d) is preventable

      If you have not yet come across this theory i’m sure there are many who could point you in the right general direction.

      • And those are all entirely false. Even one false knocks cAGW out of the running. All 4 reduces it to farce. And tragedy.

    • Regardless of what we released why isn’t it charted natural vs. human in total? I think I know but I’ll hear you out.

      It’s just evil to wash out natural and compound human co2. If you want to quote 8 billion gigatons you should quote the whole hog of total co2 production over the same time line. The cause wouldn’t like that so it’s all about framing a talking point isn’t it?

      This is what science comes down to in the 21st century?

    • When I see the term “CAGW” I think of this sort of rhetoric. It’s a comment in today’s Deseret News (Utah) accompanying an OpEd by Dr. Barry Bickmore, a local scientist and blogger who supports the idea that calamity will result from “human caused climate change”:

      “Scott Mandia | 4:29 a.m. Aug. 4, 2011

      Scientists understand that humans are overloading earths atmosphere with carbon dioxide, a heat-trapping gas that builds up like so many blankets, raising the planets temperature. The US National Academy of Sciences, formed by Abraham Lincoln to advise Congress, states that certain scientific theories achieve the status of settled facts. This is the case for the conclusions that the Earth system is warming and that much of this warming is very likely due to human activities. All major science academies (representing tens of thousands of international scientists) hold a similar position.

      Others agree. Military intelligence experts warn that climate crises could topple governments, embolden terrorists and destabilize regions. Health officials say climate change could be the biggest global threat of the 21st century. The property/casualty insurance industry lists climate change as its greatest risk.

      For our health, our national security and our economic competitiveness, we need to curb our fossil fuel addiction. Otherwise, well wind up clients of the Chinese, paying top dollar for renewable technologies that we should have invented ourselves.”

      This may not be proof that “there is such a thing as CAGW theory”, to you, but it is what most of us, IMO, are referring to, when we use the term.

    • One can start with the fact that we are watching ourselves release the stuff by the gigaton.

      Why do we do that?

      To save the naked animal from the freezing winter.

      To save the naked animal from the sweltering summer.

      To save the naked animal from a brutish, short life.

      To allow the naked animal live as a human by overcoming darkness.

    • Your seem to personalize CO2 emission by using gigaton. To me personally a gigaton is awesome (ful?) amount. BUt in the context of the atmosphere, given its size, you do the significance math.

  5. Steven asks a good question: what will it do to the calculated residence times? That depends on the assumptions and the rate equations used. I agree with Robert’s snark that we should discuss merits rather than beliefs. So, I propose we discuss assumptions or statements made in the podcast wrt such questions as what effect it would have on the residence time. Note that the effect may well be to support the IPCC model of hundreds of years because the flux increase acts as a lever on our emissions wrt residence time. Another good thought to discuss, would be what if it is worse than we thought, but it is uncontrollable? What would the estinmates of increased risk be for our continued CO2 emissions, and does the work portend to find a real smoking gun for a tipping point?
    The assumptions one way or the other and how valid they appear to be will help determine the confidence or for Robert perhaps a thread related post.

  6. ThinkingScientist

    There are two significant problems with the AGW argument that increase in CO2 in atmosphere = human contribution:

    (a) the residence time for CO2 in the atmosphere is around 5 years
    (b) The fluxes (sources/sinks) of CO2 in nature are very large, as are the error bars on their estimates:

    fossil fuel burning approx 6.4 Gt per year
    Atmospheric flux from natural sources is approximately 200 Gt of which about 90 Gt is ocean and 110 Gt is biomass
    Uncertainty on sources/sinks in nature +/- 30 to 40 Gt

    The IPCC and AGW hypothesis supporters like to talk about net CO2 because it looks scary, but compared to the actual flux of CO2 and the associated uncertainty the human contribution is actually pretty small. And we know from ice core data that there is strong evidence that warming increases CO2, not the other way round.

    • “The fluxes (sources/sinks) of CO2 in nature are very large, as are the error bars on their estimates:”

      And yet oddly despite all the uncertainty and all the fluxes, the atmospheric C02 keeps increasing and even more oddly it does so in relation to our emissions. At staggering levels of oddness it appears natural sources/sinks were approximately in sync before we started dumping gigatonnes worth into the atmosphere every year.

      But I guess you can just slap “Uncertain” on anything.

      • I don’t think it does “do so in relation to our emissions”. The Mauna Loa CO2 growth rate has been basically constant since at least 1993, while our emission rate has increased dramatically. In fact the CO2 increase has been roughly linear since the 1950’s,with the 1993-2010 rate only slightly higher than the preceding years, while our emissions have seen strongly nonlinear growth. This lack of correlation is one of the chief arguments against a human driver.

      • David

        Can you cite the source of data describing human CO2 emission rates. I am not aware of any reliable information tracking human CO2 emissions over time. it would be interesting to see how the data was complied.

      • Data is at EIA and CDIAC. In 1993 it was 6172 Gtons C/year, in 2008 it was 8749. The annual rate has increased, but it’s hard to say that the rate of increase has been notably nonlinear.

        Emission numbers basically come from accountants – burning C is expensive and well recorded.

      • Human breathing, farting and human food cosumptions were not accounted for in these official sources. More human, more food (animals and plants, well vegetables for human, grass for food animals including lands and seas) for human, more CO2 production by human.

      • You might also look at the global carbon fluxes at
        which includes an estimate of effects due to land-use changes.

      • Thank you both for your replies. I was familar with the CDIAC information, which is why I wrote the “reliable” qualifer in my question. If you review how their data is accumulated I believe you will find that their “estimated emissions” are +/- something like 20%. It is a rough estimate of human emissions, but certainly nothing more than a rough estimate

      • “error bars schmerror bars” only merchants of doubt use them /sarc

      • Be patient sharper. It will start decreasing soon, when the cooling gets going. I have been waiting for that since ~10 years. It will be priceless.

        And don’t even start with the ocean pH.

      • “before we started dumping gigatonnes worth”

        4% of total global co2 input? What percentage of GHG impact does co2 represent and include water as a GHG when you reply?

      • “At staggering levels of oddness it appears natural sources/sinks were approximately in sync before we started dumping gigatonnes worth into the atmosphere every year. ”

        Huh!!!! and we have data for that??? Are you by chance claiming that the CO2 concentrations from Ice Core so fine ( and unaffected by diffusion ) that we can find CO2 concentration in atmosphere with century accuracy? How do you even validate that data? just making such claims makes the whole theory sound like a bunch of scaremongering BS to me.

      • It isn’t odd at all. It is consistent with the lagged response of CO2 to warming conditions following colder eras. There is no geological evidence whatsoever that natural sources and sinks have ever been in step at any time during the last 500,000,000 years. There reasonable certainty about our production of CO2, but there is very little sound data on sink responses and natural sources are even vaguely near being fully inventoried. The wildly varying “estimates” on atmospheric residence time alone are evidence of this lack sound data: ca. five years to a century or more, forsooth. What this means is very simply that we have only the vaguest ideas of marine and terrestrial productivity. The estimates of volcanic production are the wildest of WAGs since we do not have any thing like a complete inventory of volcanoes, and at least three quarters of the ones we don’t know about are submarine. It doesn’t require agendas or conspiracy to create controversy in such a situation, merely lazy minds wedded to single ideas.

      • Estimates of CO2 residence time do not vary wildly. It’s just that people will not get their head around the fact that there are two different concepts. Individual C atoms are exchanged on a 5-year time-scale. But a pulse of CO2 lasts for a century or more – not necessarily with the same atoms.

        98% of the atoms in your body are exchanged every year. Residence time is a matter of months. But that doesn’t derermine human lifetime.

      • John Vetterling

        Unless I have missed something, I believe the IPCC said that CO2 resident time in the atmosphere was between 50-200 yrs. That seems like wildly varying estimates to me.

        I not trying to pick an argument, just trying to understand your point.

      • John said five years to a century. This is the persistent misunderstanding that I refer to. Five years is the relatively well-established residence time for carbon atoms. Yes, the persistence of a pulse is less well established, and a range of 50-200 years is not unreasonable. The basic issue there is that it isn’t a simple exponential decrease. There are sinks with different time-scales.

      • These CO2 residence times are all speculations without scientific basis. They are all junk data so far.

      • Well the problem is that the residence times are based on models, which are based on the assumption that the measured increase is entirely due to man. If that assumption is largely wrong or unfounded then 5 years is as good as any estimate. Freeman dyson estimated 12 years by another means but real data is lacking for all estimate and normally using a model as a substitute for data would be unacceptable practice. However running a model, as Dyson observed, is a lot more comfortable than going in the field and collecting hard data.

  7. I’ve emailed the institute and Prof. Salby to see if any video is available.

  8. Michael Larkin

    Okay. A simple technical question. I’m not quite getting the point about C12 and C13 isotopes and their importance. Can anyone explain it or alternatively point me to a clear exposition for the layman on the web?

    Thanks in advance if anyone can help.

  9. Have you listened to the podcast, or are you restricting your commentary to the introduction to the podcast on this blog?

  10. Bizarre threading issues. My question at 8:51 directed at sharper00

    • Not a threading issue, it appears my comment pointing out there were no technical details to discuss on a “technical thread” was removed.

      No I haven’t listened to the podcast. I’d like some definition of why I would want to (beyond nebulous claims of a “revolution”) and then something to actually investigate which the original post admits simply doesn’t exist because nothing has been published.

      • Well certainly a bizarre response. There were enough claims and reasoning in the podcast to merit discussion of a technical nature. the “restriction” is a fair one.

        Why not listen? Maybe you’ll find something that unravels the premise.

      • Now you are asking others to tell you what you should do? Please don’t listen if that’s your thing. I think that he asked what he asked to inform the audience that your criticisms are based on nothing more than the abstract of the talk.

      • How about listening to it purely because it’s the subject of the thread that you’re commenting on and that it’s interesting?

      • Sharperoo is just afraid to think for himself. If its not written on the sacred scrolls Sharperoo is dismissive. Next he will seek the what this means from his high priests at the temple.

      • On no account listen to the podcast.

  11. What I find curious is the complete frightened / shocked / dazzled tone of voice of the moderator at the end while performing his duty to close off the speech and the discussion. I might be imagining things, but I would guess that this presentation shook his entire basis of reality.

    • steve from brisbane

      You would be completely wrong. The video was shown on a (little watched) cable channel in Australia, and the host was a well known moderate conservative commentator in Australia who has often expressed skepticism about climate change science.

  12. I too look forward to the publication of Prof Salby’s results, until which event it seems premature to announce a revolution.

  13. So… the huge increase in concentrations of CO2 we’ve seen were mostly natural but just happened to coincide with the industrial revolution(s)? A remarkable coincidence.

    • Don’t forget that our own emissions also have to disappear somehow or else we’d have the natural ones + ours.

      • That is not how it works. You are using a simple reservoir model, thereby ignoring the entire issue of how natural CO2 levels are established. On the proposed flux model it is perfectly possible for CO2 levels to fall even as our emissions rise. Never forget that the natural CO2 flux swamps our emissions.

    • It’s not remarkable at all. CO2 hockey stick is as bad as the other one.

    • As Edim points out, the pre-1950 CO2 concentration is a bit of a hockey stick. It is based on ice core data, ignoring all data to the contrary, of which there is a bunch. Nothing in nature is constant but AGW assumes CO2 concentrations are constant prior to around 1800.

      • ThinkingScientist

        There is a large body of pre-1950’s atmospheric CO2 measurements made using the chemical assay method. There about 90,000 measurements over more than 100 years. The method was quite widely used, is reasonably reliable (accuracy about +/-3% as I recall) and shows significant fluctuation in pre-1950’s levels of CO2, including much higher asa well as lower values.

        These measurements are completely ignored by IPCC.

        On the other hand we have a single measurement station at Mauna Loa on a volcano using a sensor from which 80% of the readings are thrown away because they look wrong. No comparison was ever made between the Mauna Loa measurements and the chemical assay method. That single measurement station on Mauna Loa is the entire basis for the zero sum game of anthropogenic CO2 is the sole cause of increase of atmospheric CO2.

        The sum of all the huge fluxes in nature is assumed by the IPCC to be zero sum hence the zero sum game. If nature = 0 then all change is caused by man.

      • Latimer Alder

        Can you expand om the ‘80% thrown away because they look wrong’. This is astounding news. As is the idea that the assay method is never used to calibrate the sensor or check it regularly.

      • “That single measurement station on Mauna Loa is the entire basis…”
        No. Please look at

      • Thanks HaroldW. Some CO2 time series look interesting.

      • “On the other hand we have a single measurement station at Mauna Loa”


        The “continuous” readings at MLO are backed up with periodic “flask” measurements at other locations. There is a pretty thorough analysis of MLO measurements by a well known climate change skeptic here Eisenbach also addresses chemical assay results as well in his article.

        All that doesn’t necessarily mean that CO2 is increasing uncontrollably and we’re all gonna die. See Glassman “The Acquittal of CO2”

    • R. Nassar et al. report on an international team measuring:
      Inverse modeling of CO2 sources and sinks using satellite observations of CO2 from TES and surface flask measurements
      Atmos. Chem. Phys., 11, 6029–6047, 2011 doi:10.5194/acp-11-6029-2011

      Aggregating the annual surface-to-atmosphere fluxes from the joint inversion for the year 2006 yields −1.13±0.21 PgC for the global ocean, −2.77±0.20 PgC for the global land biosphere and −3.90±0.29 PgC for the total global natural flux (defined as the sum of all biospheric, oceanic, and biomass burning contributions but excluding CO2 emissions from fossil fuel combustion).

      Supporting Murry Selby’s analysis, the highest fluxes are “South American Tropical Forests”, “North African Grasslands”, while “South and Central Europe” is the biggest sink.

      However, I thought Selby to refer to larger subsurface variations.

    • Stilicho,
      Here’s another remarkable coincidence …
      The huge increase in concentrations of CO2 we’ve seen just happened to coincide with our actually starting to take CO2 measurements, and on the side of an active volcano no less.

      And another one …
      The start of the AGW temperature rise just happened to coincide with the invention of the Fahrenheit scale and of the registering thermometer.

  14. Whither everywhere
    Wondered carbon sinks unknown.
    Please, we need the truth.

  15. Quick and potentially daft question- how are the anthropogenic emission amounts calculated?

    I.e. how do we know how much we’re emitting?

    • Carbon emissions are mostly based on fossil fuel consumption, which is generally pretty well reported, albeit maybe not accurately. Last I knew biomass burning (mostly wood and dung), mostly in poorer countries, was not included. Verification is a major stumbling block in the climate negotiations.

      • Thanks- i was trying to figure out if the C13 attribution issues would affect these calculations, or to put it another way- to check that the determination of the amount of c02 released into the atmosphere is not ‘generated’ by the (what may be) suspect C13 detections.

  16. barn E. rubble

    RE: “He suggests that its warmth which tends to produce more CO2, rather than vice versa . . .”

    I thought this had already been well established – or settled, as it were? Further, wasn’t the misleading overlap of CO2 and temperature graphs one of the major inconvenient truths? Or is this really something new?

    Curious . . .


    • As far as I know, the consensus is the other way around (Jim D?). CO2 produce more warming than vice versa. Way more. I think 1% hotter sun results in only ~10 ppm increase. Jim D will correct me if I misinterpreted.

      I think CO2 does nothing to the temperature. If anything, it causes cooling.

      • A 1 degree warming of the ocean can increase CO2 by ~10 ppm by Henry’s Law. I will say more on this talk at the bottom. Note that you would have to increase the ocean temperature a lot to get 100 ppm of CO2 as we have in the past century, so we can be sure it is not ocean-warming alone that can account for this (beside the acidification being the wrong sign for the ocean to be the source).

      • Thanks Jim. Any links for the acidification evidence? Are you claiming that the oceanic CO2 concentration increased?

    • barn, you are thinking about CO2 versus temperature on the millennial scale, from ice cores, where temperature seems to lead CO2 by hundreds of years. This is a common skeptical argument. AGW deems that to be generally irrelevant on the anthro-forced decade to century scale we are talking about. Many warmers also argue that despite the lag most of the temperature increase is still due to CO2. That is, once the warming starts, for unknown reasons, the CO2 takes over and drives it. This looks like a theory-saving argument but there it is.

      • Except for the reduction- the drop in temp is sharp, if not sharper than the rise- while co2 continues to rise. I think that invalidates that particular suggestion.

      • The continued rise in CO2 after temperatures start to drop, as shown by the ice cores, cannot be explained by AGW without aerosols. Volcanoes must cause the temperatures to drop, and since there is almost always a volcano active somewhere, this explanation can be used to explain any temperature change that is not in accordance with AGW.

  17. ThinkingScientist

    Inline comments don’t seem to be working.

    To Sharperoo at 8.43am:

    Actually the estimates of fluxes are themselves based on difference calculations so the uncertainties are even bigger. There is a small net increase in CO2 in the atmosphere each year, but a small change in those huge fluxes (eg due to a rise in temperature) could easily swamp the contribution from fossil fuels. The current IPCC position is based on the very strong assumption that the natural flux is in steady state and any incremental change is therefore anthropogenic. This is neither supported by the data (estimated sizes of flux), the large uncertainties and the fact that CO2 residence time in the atmosphere is very short – 5 years or so. Murry Salby’s talk presents the argument that the observed changes in CO2 flux are actually in areas away from anthropogenic sources.

  18. I was mocked only yesterday when I made the same estimate of natural co2 production, 96%. Considering co2 is less than 5% of the total GHG impact even in warming circles without the magic (make believe) human co2 compounding talking point just how much relative impact could human co2 have??

    I love it that he is from CU Boulder, just another layer of social protection from the zealot attack he should expect. What are the odds he’s another right-wing denier at that hot bed of conservative thinking at CU Boulder? I’m sure the TEAM will think of something. -:)

    • The book that he wrote Curry referenced in the post was co-authored by none other than Pielke Sr.

      So that’s the link you are looking for ;).

  19. ThinkingScientist

    RE Sharperoo @ 9.06 am says

    “Don’t forget that our own emissions also have to disappear somehow or else we’d have the natural ones + ours.”

    Residence time of CO2 in atmosphere is around 5 years. Anthropogenic CO2 is being scrubbed and recycled at a very high rate and this is entirely consistent with the large sources/sinks. The natural system can swallow our contribution with hardly a burp.

    Without actually listening to the presentation you are going to find it pretty tough arguing some of thepoints. Murry Salby is constrcuting his argument from actual observations from satellites.

    • “Anthropogenic CO2 is being scrubbed and recycled at a very high rate “

      And yet, oddly, not the coincidental natural emissions leading to a net increase. Funny how it can be that human emissions are scrubbed clean after 5 years but the increase just happens to come from elsewhere.

      • sarcasm fits you badly, sharper00. It may well be that this researcher got all wrong. It may well be that you have a damned good point. It’s not with pot shots that we will discover it.

      • ThinkingScientist

        The natural fluxes are of the order of 200 Gt of CO2 per annum, the IPCC estimate of anthropogenic CO2 is 6.4 Gt. Miraculously, despite the IPCC natural source/sink numbers being deduced by difference, despite their having error bars of +/- 30 to 40 Gt per annum, the IPCC model assumes steady state for the natural system, the natural fluxes miraculously balance out (depsite error bars of +/- 30 – 40 Gt per annum) and voila – miraculously the increase at Mauna Loa is exactly the amount estimated to be added from anthropogenic CO2. The IPCC result is based on an assumption – atmospheric CO2 is in steady state equilibrium. This is probably why they also disregard/ignore the 150 years of reliable chemical assay data for atmospheric CO2 which paint a much more varied picture of atmospheric CO2. Never let data get in the way of your preferred model.

        Alternatively, it could be that CO2 in the atmosphere is influenced by huge natural events such as ENSO, PDO and (gasp – surely not) temperature increases. Murry Slaby presents a compelling argument based on real world observations to support this alternative hypothesis. And he has actual data from satellites, not hand waving IPCC estimates.

      • Not funny sharper00, but indicative of two main possibilities not necessarily exclusive. One is that the temperature is the driving force. Another is that anthropogentic emissions act as a lever to excite the natural state to a higher one. Combined with the satement that it is not controllable could indicate more reason for us to regulate CO2 not less. It will be science that demonstrates what one could or should expect. I think someone seeing this as an automatic out for AGW causing problems, indicates a lack of appreciation of the effect of different rates and how a small input can act as a lever over a long period if it causes a change of state. Those who deal with reactors, including biological reactors, know this leverage effect is typical, not rare.

      • “Those who deal with reactors, including biological reactors, know this leverage effect is typical, not rare.”

        Any reactor that is inherently unstable will eventually over time fail catastrophically. In the case of a biological reactor, evolution tells us that over time this will lead to replacement of the unstable design with a more stable design. Over time, life will evolve so that it stabilizes the climate to ensure its continued existence.

        We see strong evidence of this in the paleo records of the past 600 million years. Average temperatures have gone up and down, but have remained between 11C and 22C, with most of the time spent at either 11C or 22C, and only rarely in between.

        Current temperatures are 14.5C which if one looks at the paleo records is not a stable temperature. We should expect the temperature to either increase of decrease naturally, until they plateau at either 11C or 22C.

        The current interglacial is inherently unstable and according to the paleo records will not last. If we can affect the climate then the question we should be asking is this. Do we want an ice age earth or a tropical earth, because those are the stable climates.

      • If the sink was not variable how is it the dangerous compounding of co2 hasn’t happened long ago?

        I’m sorry the 40% human co2 contribution (current inventory of co2) based on washing the natural contribution with a static sink but compounding human co2 input is pathetic logic. How many unknowns can you fit on head of pin?

        You have to totally buy-in that all net human contributions are added to total co2 inventory. How does a pig like that fly in the science community?

      • Sharper. Use logic and not black and white thinking. Net increase can stop at any time. I am not saying it definately will.

  20. Stevev Fitzpatrick

    This argument (warmth increases atmospheric CO2) is for sure true… you need only look at the glacial/interglacial CO2 concentrations, and their ~800 year lag behind temperature (ice core data), or el Nino driven variations in the Mauna Loa CO2 trend to see this relationship looks real at all time scales.

    The problem with the argument that this accounts for much/most of the post industrial increase in CO2 is that the magnitude of recent rise in CO2 is not what you would expect based on that long term historical record, it is much (many times) greater per degree of temperature change. Roy Spencer made a similar argument a few years back (that warming of the ocean was causing a very large increase in CO2). In any case, the argument is true in part, but does not appear to explain the large majority of the industrial period rise in CO2. The simplest and most reasonable explanation is that most of the rise in CO2 has come from burning fossil fuels.

    I wrote a brief post related to this subject at WUWT a couple of years back ( which might be of some interest.

    • The simplest explaination is that the earth releases more co2 when it is warmer.

      Industrial co2 is so small and the sink isn’t understood. The retorts on WUWT are more compelling.

      • Steve Fitzpatrick

        Any simple explanation, like warming temperatures have caused the recent increases in CO2, requires consistent behavior between the increase in CO2 due to recent warming and the increase in CO2 that took place in the last (warmer than today) interglacial. The warmer temperatures in the last interglacial did not lead to CO2 concentrations even close to what is in the atmosphere today. Some of the comments on my post at WUWT were thoughtful, some much less so.. The very simplest explanation is that if you add more of something to an existing quantity of that same something, the total increases.

      • 4% or more in this case?

        Waht makes you think it is accumulated instead of absorbed by the sink? Does the sink like magic know not to absorb human co2 past a certain point and where is the proof that the (net) growth is coming from humans?

        It looks like a logical fallacy.

      • Steve Fitzpatrick

        If you read the post at WUWT, you will see that I estimated about half the emitted CO2 is currently absorbed by the oceans (perhaps with some help from increased plant growth). The sink doesn’t ‘know’ anything; it only reacts to an increase in atmospheric CO2 by absorbing more CO2. This doesn’t seem very surprising to me. Absolute ‘proof’ is hard to come by in life; usually people weigh the available data and adopt the explanation which is most consistent with the data. You seem to me not be addressing the primary argument which I raised in my initial comment here: if the recent rise in CO2 is mostly the result of warming, then the substantially warmer previous interglacial should have produced higher CO2 levels than at present, but did not; the CO2 levels were much lower. It would be nice if you could offer some reasoned explanation for this apparent discrepancy.

      • The simplest explanation is the we are using different techniques to measure present CO2 levels as compared to how we measure past interglacial’s.

        Image that you had a thermometer that averaged temperature over a full year. If you compared this to a standard thermometer reading taken in summer or winter, you would conclude that the summer/winter reading was abnormal, but in point of fact it is simply a result of the difference in the bandpass frequency of the thermometers.

      • steve fitzpatrick

        Are you suggesting that the true CO2 level during the last interglacial (and during the warmer early part of the Holocene) was actually higher than today? If you haven’t done so already, you may want to download the ice data (the best are the high resolution cores from Greenland and Antarctica) and take a look. The temporal resolution is sufficient to see even relatively brief changes in CO2. It is hard to see how any relatively long period of much higher CO2 could be missed in the ice record.

  21. Keeling (and others) has been taking the biotic out of the biosphere by examining the ratios of Ar/N2 in the atmosphere. The changes in these ratios are reporters of, mostly, temperature changes in the relative solubility of the two gasses in water.
    Ar/N2 changes report daily temperature changes, seasonal and longer term steady state levels of these two, ‘inert’ gases as they partition into and out of the aquatic and atmospheric reservoirs.
    The saw-tooth pattern Keeling observes in atmospheric, biotic, O2/N2 and CO2/N2 ratios is also present in the non-biotic Ar/N2 ratio.
    Blaine, Keeling & Paplawsky (2005) Fig 5. shows the daily response of Ar/N2 to temperature changes

    A nice paper 2008 by Nicolas Cassar et al, shows the lovely season variation in Ar/N2 changes, at different points on Earth.

    Now, the changes in Ar/N2, and the correlations with O2/N2, show us something very important; the exchange rates of, THESE’ gases between to aquatic and atmospheric reservoirs is extremely rapid.
    We can therefore reasonably infer that distribution of a biotic gas, CO2, is also in rapid dynamic equilibrium between to aquatic and atmospheric reservoirs. Meaning the annual ‘saw-tooth’ pattern first observed by Keeling for atmospheric CO2 does show the rapid biotic/chemical sequestration/release of atmospheric CO2.
    However, working out how much CO2 in the atmosphere is due to non-biotic changes, due to burning fossil fuels or to temperature changes, is a complete nightmare. One needs to be able to measure the absolute levels of Ar/N2/O2/CO2, over long (decade) time periods and at large numbers of locations.
    Figures 7 and 8 of van der Laan-Luijkx et al., (2010) show how damned hard it is to deconvolute even simple measurements and attempt to work out if you have changes in water/atmospheric temperature and changes is biotic CO2/O2 fluxes.

    Must actually do a bit of work now, but I will leave you with this.
    As we know that the atmospheric gases are in rapid dynamic equilibrium between the aquatic and atmospheric reservoirs we can use very simple maths to examine what is going on. Using a steady state approach we can get a handle on the sizes of the overall fluxes of CO2.
    At steady state the level of atmospheric [CO2] represents the sum of CO2 influx and efflux. We know that the atmosphere has altered from about 280 ppm to about 395 ppm. Over the last 50 years have increased the influx into the atmosphere by about 40%, by burning fossil fuels. To get to 560 ppm we would need to increase our burning of fossil fuel by 2.5 times. Atmospheric bomb tests show the true t 1/2 of all [CO2]atm is only about a decade.

    • Doc, I hope you have time to expand on this, thanks for stopping by

    • There is a problem with this approach: While there is a rapid equilibrium between CO2 in the atmosphere and in the ocean’s surface layer, the increase in carbon mass (CO2 + _bi_carbonates) in the surface layer is only 10% of the increase in the atmosphere, due to the equilibrium reactions in seawater.

      Further, the bomb tests only show the turnover of CO2, not how fast an excess in mass is removed. That is much longer, around 40 years half life time. The first is based on the exchange rate of about 20% over the seasons, while the latter is based on the sink rate, which is only 4 GtC per year (the current difference between human emissions and what shows up in the atmosphere).

  22. Professor Salby’s talk centers around well known effects of temperature on the fluctuations of CO2 ie volcanoes and enso. He says that the IPCC does not know this. There are quite a few climate memes in there as well. I’m not sure this talk is going to cause any stirs outside the blog world.

    • “He suggests that its warmth which tends to produce more CO2, rather than vice versa – which, incidentally is the story of the past recoveries from ice ages.”

      Does IPCC “knows” this?

      • Yes. Either he does not know this, or has come up with numbers that are way off the consensus evidence. It’s hard to know which from his podcast.

      • Grypo,

        The consensus is that global warming causes more CO2 increase than the CO2 increase causes warming? Of course we have to agree on the metrics, but I don’t think that it’s the IPCC consensus.

  23. While we wait, I searched for Carbon Cycle on Amazon, and sifting by price gives the following three books. Has anyone any professional feedback on their value?

    Kirill Y. Kondratyev, Vladimir F. Krapivin, Global Carbon Cycle and Climate Change, Springer Praxis, (hard 2003, paper 2010) ISBN-13: 978-3642056420

    T. M. L. Wigley (Editor), D. S. Schimel (Editor) The Carbon Cycle [Paperback] Cambridge Univ. Press312 pages 2005, ISBN-13: 978-0521018623

    Christopher B. Field (Editor), Michael R. Raupach (Editor), Susan Hill MacKenzie (Preface), The Global Carbon Cycle: Integrating Humans, Climate, and the Natural World (Scientific Committee on Problems of the Environment (SCOPE) Series) [Paperback] 568 pp, Island Press; 1 edition (March 15, 2004) ISBN-13: 978-1559635271

  24. JC,

    Can you please state for the record what *specifically* you found “sufficiently important” about this “that we should start talking about” it?

    Thanks in advance.

  25. “Anyone who thinks the science of this complex thing is settled is in Fantasia.”

    We’ve always been at war with Fantasia.

  26. Wow, I’m stunned.

    Folks who read J.C.’s blog might start by reading the posts at RealClimate that explain the evidence — and not just from 13C/12C ratios.

    Start here

    and work backwards to the slightly more technical posts:

    Incidentally, the 13C/12C ratio of the ocean is unequivocally *decreasing*, just like the atmosphere. I’ll be curious to see what machinations Salby goes through to explain that (if indeed he mentions it at all — it will be rather telling if he does not).

    • sharper00 made a very similar contribution, mr Eric.
      Judith followed with an interesting link:

    • ThinkingScientist

      Eric Steig, its great that you came and posted at Judith curry’s blog.

      It would be even better if you would actually state the arguments and participate in the discussion here where comments are unmoderated/uncensored.

      Of course, you may find your arguments a little more difficult to carry in an open forum like this one where you do not have editorial control and the means to delete and “moderate” comments that you don’t like.

    • Eric Steig, what did you think of Prof Salby’s talk when you listened to it?

    • Dr. Steig,
      Thank you for dropping by. It is great that our hostess will allow you to speak freely. But that is a characteristic of blogs dvoted to actually studying an issue.
      As to Dr. Salby’s work, which none of have read:
      No need for a review or revisit of the question? No possiblity of anything new to learn?
      Everything is settled, no need to check, just move on nothing to see?
      Why would someone from a free discussion blog want to go and be subjected to censorship, by the way?

    • Dr Steig, I’d like to add my warm welcome to Climate Etc. Others have assumed that you have listened to Professor Salby but I make no such assumption. What I do assume is that you and your esteemed colleagues at RealClimate have read this sentence:

      He said he had an “involuntary gag reflex” whenever someone said the “science was settled”.

      That raises an fascinating question for me. Is it possible for one scientist’s involuntary gag reflex to provoke exactly the same in another scientist, but for opposite reasons?

      • Richard,

        As with many things Bolt writes (although this is more of a trivial error than most), he got it wrong. Salby actually said that not about “‘settled’ science”, but rather when “politicians” and those of a certain bent invoked “*the* science”.

        Should we assume that you didn’t actually listen to the presentation yourself?

      • Thanks for your perspective. I’ve just read this post for the first time and an hour has not elapsed since I chanced upon it and then took the detour to Bishop Hill to read Paul Dennis on the matter, as advised by Judith. From that you can deduce that I have not listened to the podcast. But I did read that summary by Judith, which you say she got from Andrew Bolt, and I also assumed that Dr Steig had read it.

        As for the difference you report, it seems a trivial one to me. Invoking the science and saying the science is settled are for me one and the same. But everyone to their own.

      • The ‘gag reflex’ line is right at the end of the presentation (30mins before Q&A). He did say ‘invoke *the* science’ but went on to say the science is never settled.

      • As I heard it, Salby was deliberately vague in his condemnations of “advocacy” and characterizations of some involved in the debate about warming due to CO2 emissions.

        In fact, it was that lack of specificity that IMO, (with me not being a position to evaluate the science of his presentation) – that places him squarely in an “advocacy” position. It seemed rather clear both from his presentation, as well as in his answers to the follow-up questions, that Salby is not merely presenting science here, but engaging the politics of the debate process in and of itself. He was clearly obliquely criticizing people – perhaps scientists or perhaps scientists as well as politicians – and not simply criticizing scientific theories.

        That might or might not be problematic in an of itself (although I would say usually it is), but when he launches such criticisms of individuals, without a full explanation of context, and with indirectness and inuendo, and without specifying who he is referring to so we can distinguish his inuendo from political conspiracies – he does himself a disservice (IMO) and makes it impossible for someone like myself to evaluate his position.

      • Joshua:

        In order to evaluate your objectivity I need to know if you will apply these rules equally to all sides:
        “That might or might not be problematic in an of itself (although I would say usually it is), but when he launches such criticisms of individuals, without a full explanation of context, and with indirectness and inuendo, and without specifying who he is referring to so we can distinguish his inuendo from political conspiracies – he does himself a disservice (IMO) and makes it impossible for someone like myself to evaluate his position.”
        lets take this:
        1. criticism of individuals without specifying who he is referring to

        You say that this makes it impossible to evaluation his position and does him a disservice.

        Are you prepared to make this same kind of statement about others?
        can you guess who Im thinking of?.

      • I assume you’re thinking of me.

        Where did I offer oblique criticisms of individuals without specifying who I was criticizing and giving context for that criticism?

      • All from the shelter of anonymity. That’s brave.

      • I’ll never understand how people think that they can determine something about someone’s character on the basis of whether they post anonymously on blogs.

        My assumption is that there are people who lack “courage” who post under their names just as their are people with “courage” who post anonymously.

        Certainly, there are many people who are publicly recognizable who I think lack courage.

        Do you base you assessment of your own courage based on the fact that you assign your name to your posts? Really? That really ranks highly on your list of ways to assess someone’s courage? Really?

        So if I beat my wife and posted on blogs under my own name, you’d consider me courageous?

        The fact is that you know absolutely nothing about me personally. I’d say your assumption that you does not exactly speak highly for your analytical abilities – although it does suggest that you have some need to pump yourself up. Meanwhile, I’ll stick to people that I actually know and have reason to respect to get feedback on my amount of courage or lack thereof.

        What attribute do you assign to people based on their propensity to take cheap shots on blogs by interjecting insults into dialogue between others?



        That’s not the first attribute that jumps to my mind.

      • Joshua –
        I’ll never understand how people think that they can determine something about someone’s character on the basis of whether they post anonymously on blogs.

        “whether” is immaterial. But “what” is relevant. As in this rearrangement of your words –

        people can determine something about someone’s character on the basis of what they post anonymously on blogs.

        Which is something you may not have considered even though it’s true.

        The fact is that you know absolutely nothing about me personally.

        Many of us know more about you than you believe. Including how to sometimes “push your buttons”. You tell us something about yourself every time you write – sometimes it’s something new, sometimes something old. We ALL do that. Assuming you’re different is just self deception.

      • lolwot –
        I just think use of ones real name online is a little pretentious

        And I think you’re afraid to use yours.

      • I don’t need to prove it. Clearly, since he posts anonymously, he lacks courage.

        I learned that from Anthony Watts – and the lesson was further reinforced in this thread by Richard.

        And in another thread I learned that if fewer people posted anonymously, there would be a higher S/N ratio.

        Because, you know the S/N ratio is so high when famous people, like Sarah Palin, opine on various subjects.

        It’s very important when you consider even national security issues with Russia as Putin rears his head and comes into the air space of the United States of America, where—where do they go?

        or perhaps

        I know that John McCain will do that and I, as his vice president, families we are blessed with that vote of the American people and are elected to serve and are sworn in on January 20, that will be our top priority is to defend the American people.

        Heh. All S, no N there. Nosireebub. Because, after all, we know her name.

        Too funny.

      • I notice a lot of people on this thread are cowardly hiding their middle names and their bank details

      • I never use the term liberal for progressives – a liberal is for free people and free markets and is not a pissant progressive. The effette was used in relation to progressives threatening to kick the butts of tea partiers. As the progressives are all hat and no cows or guns – it seemed unlikely.

        If you click the button on my title – you will be sent to a web page with my full name and title.

        Robert Indigo Ellison
        Chief Hydrologist

        Note that my title derives from Cecil (he spent four years in clown school – I’ll thank you not to refer to Princeton like that) Terwiliger – who was Springfield’s Chief Hydrological and Hydraulical Engineer. Cecil opined that in some cultures it was a sacred calling. Given the importance of water both practically and symbolically there is more than an element of the sacred. Water is scared but carbon dioxide is unholy.

        ‘Am I some poor merchant of doubt selling shopworn and
        threadbare wares on the ebays of the ideas marketplace?
        Let me take stock then in a dismal reiteration of my poor
        argument that is my faint hope to delude and dismay you.

        Unless we can count on some mad and untestable theory,
        then the unholy carbon ghost must grasp the photon closely
        in warming arms for a period of no less than 80 years or so.
        Or until judgement day – whichever comes before the cart.’

        a fragment from Song of a Climate Zombie

        Is Salby the mad theorist overthrowing the ‘unholy carbon ghost’? We shall see.

    • Machinations?

    • I am stunned too Eric. There are multiple lines of evidence that the recent CO2 rise is human caused.

      • I was stunned by the same thing. Haven’t these people heard of multiple lines of evidence? Like for the Hockey Stick? And for high climate sensitivity? I certainly have, I’ve heard about it again and again and again. Hasn’t ever convinced when I’ve looked into it but I’ve sure heard about it. But I, like Judith, only much more so, am not an expert on the carbon cycle. I cannot help but look forward to the myriads of lines of evidence I’m going to find in this area, with the help of Professor Salby and his loving admirers in the rest of climate science.

    • TimTheToolMan

      If I’m understanding the argument properly the 13C/12C ratio is largely irrelevent. There is no question we’ve put masses of CO2 into the atmosphere. Its one of the few things thats certain. But the argument as I understand it is that you can think of all that CO2 as fully sunk…and then the natural processes (mainly based on temperature?) are releasing it independently.

      I believe that is consistent with all your measurements except it would have profound impacts on AGW as its understood.

    • Recent analysis of RC traffic has shown just how alarmingly high the censorship is. One could hardly expect any such site to provide an objective scientific discussion.

  27. Alexander Harvey

    If I be right there are some things about this presentation that seem a bit crook.

    Whatever he has discovered that is new, it is not that there is a link between temperature and the carbon cycle or soil moisture and the carbon cycle.

    I am also having trouble tracking down his presentation to IUGG 2011 Melbourne. He was slated to speak on July 5th but on Antartic Ozone, but I cannot find when he presented the material under debate. However the program was provisional:

    and doesn’t necessarily reflect what unfolded.

    That he should sit on something so important and sell his book on the strength of it, is his own affair, but that he doesn’t seem to be wishing to publish formally for many months seems a little mean.


    • What seems mean to my eyes is probably just lazyness or distraction on your behalf. He *did* write this thesis on a paper which has *already been approved and peer-reviewed* for publication. The publication is the thing that will take months itself.

      • Alexander Harvey

        True, he says that the work is a year old, written up six months ago and to be published in 2012.


    • The issue with the delay in publishing is probably the length of his paper. You can only publish short papers in Nature, Science, GRL. A more lengthy paper published in JGR or say an AMS journal would commonly take 6 months to be published, although some journals make in press papers available pre publication. And some journals do not allow you to prepublish drafts of the paper on your own website. I am aware that several people have emailed salby requesting a copy of his paper and ppt slides. Lets see if this attention motivates him to do so. He seems to operating in the traditional mode of waiting until the paper is published.

      I’ve spotted a few relevant links on the web:

      JoNova has an extensive post here

      • Alexander Harvey


        I thought he said that half of the content would be in his new book prior to formal publication.


      • I guess this is the half that isn’t in the journal article, that is how I interpreted his statement.

      • Yes, Jo Nova has this on the delay to the paper:

        “The up and coming paper with all the graphs will be released in about six weeks. It has passed peer review, and sounds like it has been a long time coming. Salby says he sat on the results for six months wondering if there was any other interpretation he could arrive at, and then, when he invited scientists he trusted and admired to comment on the paper, they also sat on it for half a year.”

      • From that link,

        “The trend in CO2 derives from a hysteresis in its
        annual cycle: More is emitted during half of the
        year than is absorbed during the other half. The
        residual, which accumulates to fo rm the trend,
        provides a record of net emission. It is shown
        to track the satellite record of global -mean
        temperature, which fl uctuates b etween years.
        Temperature changes of 0.5 – 1.0 K are attended
        by modulations o f C O2 emission as large as
        100%. Much the same dependence is exhibited
        by isotopic composition. The temperature
        dependence o f CO2 parallels that of water vapor,
        the dominant greenhouse gas. Such dependence
        governs CO2 emission for temperature changes
        that are cl early of different origin, including the
        eruption of Pinatubo and the 1997-1998 El Nino.”

      • Why yes, JoNova’s post sure is “extensive” but I question whether it’s any good. Specifically, please comment on whether, to your knowledge, a 2.6% difference in isotope ratio truly makes it “hard to tell their ‘signatures’ apart.”

        Prof Salby points out that while fossil fuels are richer in C12 than the atmosphere, so too is plant life on Earth, and there isn’t a lot of difference (just 2.6%) in the ratios of C13 to C12 in plants versus fossil fuels. (Fossil fuels are, after all, made in theory from plants, so it’s not surprising that it’s hard to tell their “signatures” apart). So if the C13 to C12 ratio is falling (as more C12 rich carbon is put into the air by burning fossil fuels) then we can’t know if it’s due to man-made CO2 or natural CO2 from plants.

        How “hard” is it, really? Can it be done?

        Off hand, I think it can be done, and I think that it’s not even particularly difficult with the right modern instruments.

  28. He suggests that its warmth which tends to produce more CO2, rather than vice versa – which, incidentally is the story of the past recoveries from ice ages.
    If you open a warm carbonated drink it expels high pressure CO2
    If you open a cold carbonated drink it does not spew much.

    Of course there are higher levels of CO2 when the oceans are warm.

    It is not possible that a tiny trace gas caused the huge warming’s as we came out of ice ages.

  29. I was just about to post that we should expect some pseudo-response from RealClimate even before Salby’s paper appears in print. Surprise of surprises, Eric Steig has already posted here providing an old blog post published six years before Salby’s analysis came public. Steig’s cited post cannot possibly address the science Salby has done.

    I have to wonder if Steig even bothered to listen to the podcast.

    • “Steig’s cited post cannot possibly address the science Salby has done.”

      As far as I can tell, Salby hasn’t done any real science. He appears to have no comprehension of the actual science of the carbon cycle. He doesn’t appear to have read Chapter 7 of the IPCC thoroughly: Figure 7.4 already shows the year-to-year variability that he is focusing on, and he ignores all the discussion made therein which shows that these variations are indeed captured within the existing framework. He doesn’t understand how carbon cycle models work, he dismisses ice cores. He apparently gave the paper to some scientists he knows, but I doubt that any of them were actually carbon cycle experts.The talk is just embarrassing, and it is embarrassing that it is being given prominence on this website. This is just SkyDragons all over again.

      • As far as I can tell, Salby hasn’t done any real science.

        Yes, no science here.

      • burned!

      • Lol. ‘M’ needs to get Moneypenny onto the background research. Q won’t be happy that he’s administered another footshooting to the Team

      • M,
        Are you taking debate lessons from Michael Mann? You sound just like him and just as unconvincing too!

        Anyone who listens to Salby can tell he has done his homework. He has been sitting on his results for a year trying to find some error in his work. This is an important step in science which is far too often neglected by the Hockey Team. No, Salby seems to be very well acquainted with Chapter 7. He is, after all, Climate Chair at his university.

        A little more humility and a little less hubris would help your side think more clearly. And it would help you come across to the public as more thoughtful.

  30. Over at BishopHill’s blog, there is a good technical discussion with Paul Dennis

  31. I think that was a bit uncalled for ,Venter. Eric Steig was at least reasonably polite. We should not stoop to their level of snark or we undermine our own credibility.

    • ThinkingScientist

      If Eric Steig were prepared to face critics openly without hiding behind censorship and moderation at Realclimate then I am sure we would all be very happy to engage with him and be polite.

      But if, as I suspect, its simply a smokescreen by Realclimate to pop up here, throw out a “the science is settled – come and see at Realclimate” comment and then disappear without making any argument in open forum then I think Venter has a point.

      Anyone who has attempted to have a discussion at RealClimate that disagrees with their views will already know that Eric and his pals are certainly not polite and indulge in censorship and “moderation” of comments they don’t like. WUWT had a nice post on the level of deletions at RC. I prefer my discussions to be open and without censorship.

      • There has to be a large inquiry has to the conduct of
        this scientific debate when this nonsense has died a
        natural death. I can only see the death coming when
        the CO2 ppmv figure actually trends down following
        the recent temp declines in the Pacific al nina large
        events that have caused the climate events not seen in
        a century (that is multi-decadal CYCLES) .

        For those that actually listened to the podcast you could not miss
        the stunned unease in the questioners voices. I wonder what
        they would do- nothing ignore this data point.

    • Rob,

      Eric came on with an uncalled and arrogant post. I replied to it. I see that JC has removed my post as well as another post of mine agreeing with what Ron Cram posted. Yes, maybe they were not technical. So was Robert’s and a multitude of other posts. But they are there.

      Dr.Curry, could you kindly clarify?

      • I am working to esp delete posts that violate blog rules

      • Judith –

        It might help if you clarified what measure you are using to determine “relevance.”

        As it stands, without such clarification, one might think that there is reason to question how you determine which posts are sufficiently technical in nature.

      • I’m happy for you not to delete any that may be calling me a Nazi, or whatever. I think I can look after myself without resorting to that level.

        But it does strike me as odd that those who do indulge in verbal bullying and name calling are usually the first to cry if there is any retaliation. I’d just make the point that those who can’t take it themselves shouldn’t dish it out to others.

      • I’m happy for you not to delete any that may be calling me a Nazi, or whatever. I think I can look after myself without resorting to that level.

        There is another issue with deletion of posts and responses. It takes the context out of threads. I now read about Venters uncalled for posting without being able to read what it exactly was.

        Mind, I am merely a visitor. I don’t make the rules of this blog and I am absolutely fine with that. The above remark was simply for consideration.

  32. I’m reluctant to spend an hour on a podcast when the crux of the issue will be found in a published paper, along with the description of all the technical details, graphs, methods, etc. However, I will try to tune in to at least part of it. At this point, the evidence that the natural variations Salby cites can transiently affect atmospheric CO2 concentrations is plausible, but the claim that they explain long term multidecadal or centennial trends is untenable. Rather, the evidence that the approximately 40 percent rise in atmospheric CO2 since preindustrial times is completely or almost completely anthropogenic is compelling in that it is derived from multiple independent sources. Some are described, with references, in the RC piece by Corrine Le Quere, but other data include the quantitative bookkeeping from industrial emissions records, as well as data on changing atmospheric O2 and C14 levels.

    I have no quarrel with Dr. Curry’s decision to bring this topic to our attention, although I’m worried that use of terms such as “wow” or “revolutionize” will turn out in retrospect to signify some naivete about a topic that has been thoroughly evaluated over many decades. Is it possible that Salby, although cited here as advancing only arguments already well known in the blogosphere, has in fact turned up something new? I doubt it, but when his paper appears, we will have a chance to judge. If I have anything to add after visiting the podcast, I’ll comment then.

    • Well, Fred, it is certainly nice to see you are open to new data!

      I certainly don’t have this all figured out yet, but it is apparent Salby has made some new observations. He did not particularly like the interpretation of the data, but has not been able to find anyone in the field who can come up with a viable alternative to his interpretation.

    • Fred
      With all due respect, this is yet another example where you try to sound scientific in your writing, but demonstrate your bias in looking at information based upon what you have written. Let me further explain-
      The link you cited is one of the most blatantly misleading articles that could be written on the scientific topic “what percentage of atmospheric CO2 is due to humans. The article states:
      1. “all of the recent CO2 increase in the atmosphere is due to human activities”
      2. “There is a lot of evidence to support this statement which has been explained in a previous posting here and in a letter in Physics Today “ My response- The 1st link is simply incorrect science when it explains that C14 can be used to make this determination, when that is known to be inaccurate due to the unstable ratio of C14 in the atmosphere since the late 1940’s. The 2nd link also fails to describe the problem of using C14 and goes on to explain how we can also use C12/C13. What is absolutely fails to mention is that when using C12/C13 and tree ring data the margins of error in the calculations make them useless for the intended purpose.
      Fred writes—“Rather, the evidence that the approximately 40 percent rise in atmospheric CO2 since preindustrial times is completely or almost completely anthropogenic is compelling in that it is derived from multiple independent sources.”

      My response- Fred what a crock. That hard evidence certainly does not exist although the conclusion may be correct. We have no data to tell us reliably what percentage of current atmospheric CO2 is due to humans today, last year or ten years ago. For someone to claim otherwise is either being ill informed or an outright lie. The multiple independent sources are what to claim the rise is “ALL or Almost Completely” due to humans.
      Fred writes- “as well as data on changing atmospheric O2 and C14 levels.”
      My response- Please show how O2 or C14 are used to make this determination Fred. You might be able to make inferences, but certainly not definitive determinations.

      Let’s be honest about the science of what we know and are still learning about. We know humans are putting a lot of CO2 into the atmosphere. We also know that natural non human emissions vary greatly over time.

    • I have since listened to the podcast. I have to be tentative because it was audio only without the slides, but as far as I can tell, it confuses short term interannual perturbations with long term trends, despite a contrary claim apparently based mainly on correlation coefficients. The short term fluctuations do involve a variety of non-anthropogenic processes, whereas the rise from preindustrial levels of 280 ppm to the current levels of about 390 (did Salby misspeak and say 380 or did I mishear him?) can only be accounted for by anthropogenic processes – mainly fossil fuel burning and deforestation, with little room for other variables. The C12/C13 isotope ratios are only part of the story, although it is hard to imagine a non-biological (non-plant) source of C13-depleted carbon, and a major non-fossil fuel plant source would require us to believe that plants have been massively decimated since preindustrial days – far beyond known land use changes. The C14 deficit (referenced via tree samples back to pre-atomic bomb days) shows that the emitted carbon is very old (probably more than 50,000 years old given the 5600 year half life of C14), and that age is hard to attribute to something other than fossil fuels. Needless to say, the most direct evidence involves the record of human emissions such that these are about twice what has been added to the atmospheric concentration, and must be accounted for – they can’t simply disappear. The accounting is resolved by the accumulation in known sinks, mainly oceanic, where observed increases in dissolved inorganic carbon and reductions in pH are incompatible with the oceans serving as a net source and require it to be a substantial sink.

      I conclude, not unfairly I hope, that Salby’s claims have no merit, and I predict that they will have little impact on scientific thinking about atmospheric CO2 levels.

      • Alexander Harvey


        FWIW he did say 380 ppmv and that measurements started in the 60s and then later says 1960.

        What I found more troublesome is that around the half hour mark after he has spoken about the linkages between temperature and soil moisture and the carbon cycle he says (nearly verbatim) regarding AR4:

        “the behaviour you’ve seen was not known at the time of that report; were it the IPCC could not have drawn these sweeping conclusions that it did”

        I do not know what to make of that. Linkage between temperature and the carbon cycle has cetrainly been known for ~50 years (I asked the M. Loa guys some years ago) and a relation between soil temperature and moisture and the cycle is mentioned in AR4 WGI (ch 7?) somewhere or other.

        I presume that he hasn’t read the report and he is not well aquainted with previous analysis regarding the CO2 record. He is quite definite in his assertions.


      • Steve Fitzpatrick

        You seem to have accurately summarized the relevant issues. I agree that the argument he advances is almost certainly without merit. There are too many independent lines of evidence which point to the burning of fossil fuels as primarily responsible. Any one of these would be a strong case against Salsby’s argument. Together, they are an overwhelming counter argument.

        I must admit that I am a bit surprised Judith highlighted this presentation; the basic idea has been around for a long time, and it is no more consistent with the available data now than it was the last several times it was advanced. There are lots of areas where climate science orthodoxy skates on very thin ice, and where doubt of its validity rests on technically credible arguments; this is not one of them.

      • To add briefly to my earlier point about the difference between short term CO2 growth rate fluctuations due to temperature changes and their inapplicability to long term trends, if we regress CO2 flux rate against temperature, it will show that a rise in temperature induces a change in flux rate in or out of terrestrial or oceanic reservoirs. This could be an increase in net outward flux if the climate is near equilibrium, or in our current climate, a reduction of net flux into the reservoirs, but this is because the proximity to equilibrium between the atmosphere and the reservoirs has been perturbed. Once the system returns toward equilibrium, the CO2 flux rate will decline back toward the earlier values despite the higher temperature. The time for most of this to occur is probably measured in a relatively few years. Data derived from these short periods can’t be assumed extrapolable to century-long intervals.

  33. I think we ought to contrast this with the statement on British TV by Sir Paul Nurse of the Royal Society that humans contribute seven times more CO2 than natural sources:

    What should rankle is the absolute certainty of his statement, not just that it’s incorrect.

    • Sir Paul Nurse is talking about net contributions. Naturally, gross emissions and gross absorption of CO2 are equal. So, net contributions in that sense are zero. I think he may have been talking about emissions from volcanoes, but I’d argue they are natural too and I would have to agree he hasn’t explained himself very clearly.

      An good analogy, of the CO2 build up problem , would be the workings of the a large economy like the USA’s. If exports and imports are equal and opposite then everything is in balance. But if say imports are 2% larger than exports for one month, or even one year, then there is still no problem. But if it carries on for over 150 years those 2% imbalances start to add up.

      150 years later, its no good saying that there is no problem because the imbalance in imports is only 1/50 of the total level of imports.

  34. After listening to the podcast, it confirms that aCO2 is swamped by natural flux of the carbon cycle. But we knew that already. Salby pretty effectively pokes holes in the isotope argument (and the RealClimate post), but I am not certain Salby answers all of the relevant questions.

    Prior to Salby, we estimated about half aCO2 ends up in the atmosphere. After taking Salby’s observations into account, where is the aCO2 going? I cannot fathom a mechanism by which nature recognizes an zCO2 molecule and automatically sends it to a CO2 sink. Or is the argument that the carbon cycle is so big that any part of human contributions which may end up in the atmosphere are negligible?

    I think this is a very interesting subject. Thank you, Dr. Curry for bringing it to our attention. I look forward to the discussion.

  35. You don’t need isotopic arguments to demonstrate that the observed rise in atmospheric CO2 is anthropogenic; there is a much more straightforward argument. The annual rise in atmospheric CO2 has been smaller than the volume of anthropogenic emissions (fossil fuel and land use) every year for the last 50 years. If the environment were a net carbon source, the annual rise in atmospheric CO2 would be greater than anthropogenic emissions, not less. This mass balance argument establishes beyond reasonable doubt that the natural environment is a net carbon sink, and hence is not the cause of the observed rise in atmospheric concentrations.

    Now if Salby can explain why the annual increase is less than anthropogenic emissions, without anthropogenic emissions being the cause of the rise, then he may have something worth publishing.

    • Unless the sinks are overriding both and only ‘allowing’ a certain remainder amount to be present- like for example a slowly shifting buffer system.

      You can add all you want, but the observed increase will only be what is not handled by said system. It is the shift in the system itself that dictates the free co2, not the amount of emited co2, though this of course assumes a non-saturated system,

      • The fact that anthropogenic emissions exceed the annual rise established beyond doubt that the natural environment is a net sink. While the natural environment is a net sink it is OPPOSING the rise in atmospheric concentrations, not causing it. This is true regardless of the behaviour of individual fluxes. As I said, any argument that says man is not responsible for the observed rise needs to be able to explain why the observed rise is less than anthropogenic emissions. This isn’t rocket science, it is just conservation of mass.

        There are questions in climate science where there is significant uncertainty, but this isn’t one of them.

        N.B. looking at the growth rate tells you nothing about the long term trend (hint: what happens when you differentiate f(x) = cx ?). Analysis of the growth rate might tell you what causes the variability around the long term trend, but it tells you nothing about the long term trend as the differencing operation used to get the growth rate makes the long term trend dissapear. It sounds as if that is the basis for this study, but it has been raised before (e.g. by Roy Spencer), it was wrong then as well.

      • Yet the logic doesn’t flow- 95% (ish) of the co2 in the atmosphere is naturally released- only the rest is anthropogenic.

        So your argument only holds water if we ignore the naturally releaed carbon dioxide.

        So yes, the earth is a net carbon sink, but the fact that anthropogenic releases are estimated to be higher than the actual amount in the atmosphere proves nothing- except perhaps that the whole system has an exceptionally good capacity to ‘cycle’ carbon.

        My buffer example seems to still stand, espeically if there is doubt over the c13 attribution. Unless of course i’m missing something,

      • labmunkey, your error is concentrating only on emissions. The natural environment takes up more than it emits, and it is the difference between emissions and uptake that governs the rise in atmospheric CO2. If you save $5 a month and your wife saves $95, but spends $98 a month, which one of you is responsible for the rise in your savings?

      • Hang on- i thought we didn’t KNOW all the natural sources of co2? For example, we’ve consistently underestimated the amount released from the oceans.

        Secondly- if the environment takes up more co2 than it emits- pre industrial revolution there should have been no c02 in the atmosphere-you can’t have it both ways. I think you’re making an unfounded assumption regarding the natural rates of emmision and loss.

        Further, if your explanation was correct, this would be the first example of a naturally occuring buffer system that is ‘tipped’ by such a (relatively) small adition of co2 that i’m aware of.

        I don’t think your logic holds- i’m really not trying to be obtuse here, i just don’t think your explanation is correct.

      • O.K. in that case, if you think the natural environment is a net source, then explain why the observed rise is less than anthropogenic emissions. If the natural environment is a net sink explain why it is the source of the rise. This isn’t my argument, it was in the iPCC WG1 report and it has appeared in numerous papers on the carbon cycle. This blog is too slow, but I’d be happy to discuss this further at, where this issue has already been discussed at some length (quite a lot of it by me ;o).

      • Secondly- if the environment takes up more co2 than it emits- pre industrial revolution there should have been no c02 in the atmosphere-you can’t have it both ways.

        By that logic, the only possibility is for the environmental CO2 fluxes to be precisely balanced — otherwise, the atmosphere would be either 0% or 100% CO2.

        If you think it’s not possible for the environment to be a sink of CO2, why would you think the environment could be a source of CO2?

        [For anyone who’s genuinely puzzled by this apparent dilemma, consider finding a copy of Bill Ruddiman’s book “Earth’s Climate: Past and Future”, which has nice descriptions of how CO2 fluxes change at all time scales, from interannual to tectonic].

      • You’re missing the boat entirely. We currently emit 30 gigatons of CO2 a year, and the atmospheric concentration is currently rising by 15 gigatons of CO2 per year.

        So what’s happening to the remaining 15 gigatons that we emit, that doesn’t end up in the atmosphere???????

        Obvious answer: it’s being absorbed by oceans and land. Since oceanic carbon is observed rising, and land carbon can be strongly inferred to as well, it all makes sense. For everyone but Salby, who insists that oceans and land must be losing carbon instead!

        dikranmarsupial has it exactly right. Salby is violating conservation of matter. His paper cannot possibly pass peer review.

      • How do we know how much the natural environment takes up? – genuine question

      • Mostly by mass balance. We know how much carbon we add to the atmosphere, and we know how much remains in the atmosphere. The missing part is obviously taken up by the environment. Figuring out where it goes in the environment is a little trickier, but roughly half goes into the oceans and the other half into soils and plants.

      • But what about the total taken up by the environment – not just the CO2 we emit but also the natual emissions? I take your point about the increase in atmospheric CO2 being less than what we emit, but unless we know the totals emiited and absorbed it is hard to understand the errors and sensitivities involved.

      • But what about the total taken up by the environment – not just the CO2 we emit but also the natual emissions?

        Hi, RobB. Guess that wasn’t clear. The environment (currently) takes up a quantity of CO2 equivalent to all of its own emissions, plus about half of ours. Here’s a mathematical way of expressing it:

        A = CO2 emitted by human activities (known from “accounting” to within 20% or so)

        B = CO2 absorbed by human activities (this is pretty small for now)

        C = CO2 emitted by natural sources

        D = CO2 absorbed by natural sinks

        E = annual increase or decrease of mass of CO2 in the atmosphere; this is easy to measure and is known quite precisely

        So, (A – B) is the net CO2 flux to (or from) the atmosphere associated with human activities. Likewise, (C – D) is the net CO2 flux associated with the environment. Finally,

        E = (A – B) + (C – D)

        Since we know that (A – B) is actually larger than E, we know that (C – D) must be negative, and thus more CO2 is absorbed by nature than is emitted by nature (under current conditions).

      • Thanks, J, I understand all of that. What I was trying to ascertain were the absolute values in Giga Tonnes of C and D and compared to A and B.

      • My bad – I found it further up thread. Thanks anyway.

      • But, your little algebra says nothing about the relative size of C and A-B! C could be 1,000,000,000,000,000,000 times larger than A-B, and you have no way of knowing it! D could totally remove A-B with hardly a flicker of acknowledgement, and still fall behind in keeping up with C. You. Do. Not. Know. Saying “While the natural environment is a net sink it is OPPOSING the rise in atmospheric concentrations, not causing it” is, there is no sugar coating it, STUPID.

      • Bart writes: Saying “While the natural environment is a net sink it is OPPOSING the rise in atmospheric concentrations, not causing it” is, there is no sugar coating it, STUPID.

        Bart, please stop, catch your breath, and think for a moment.

        Under current conditions, on annual timescales:
        1. The net carbon flux from human sources to the atmosphere is positive.
        2. The net flux from natural sources is negative.
        3. The magnitude of the former net flux is approximately twice as large as the latter.
        4. Carbon is accumulating in the atmosphere.

        None of those facts is seriously in dispute.

        If one wants to just answer the simple and obvious question “Are human emissions responsible for the observed rise in CO2?” the straightforward answer is “Yes.”

        One can make this quite a bit more complicated, because as you correctly note the magnitude of the gross fluxes (e.g., natural sinks) isn’t independent of the atmospheric concentration, so one can’t just say that if we removed all human emissions the net natural flux would still be negative and atmospheric CO2 would be decreasing.

        But that’s not really relevant to the question most people in this thread are asking. They want to know what caused the 120 ppm rise in atmospheric CO2 since the time when humans first began burning fossil fuels. This rise — as large as the CO2 rise from the depths of a glacial to the peak of an interglacial — rapidly brought CO2 concentrations to a level never seen in at least the past 800,000 years, and it happened at exactly the time when humans started burning coal and oil. The atmospheric rise was also accompanied by a flux of CO2 from the atmosphere to the ocean.

        The only reasonable answer to that question people are asking is “human emissions caused the rise”.

      • J | August 6, 2011 at 8:57 am |

        “Bart, please stop, catch your breath, and think for a moment.”

        J – please stop, and take your own advice. You are babbling incoherently. See my post at August 6, 2011 at 7:37 am. You are being monumentally obtuse.

      • No, Bart. I’ve referenced your point from that comment, right here (“One can make this quite a bit more complicated, because as you correctly note…”). Ultimately, what you say there is basically irrelevant to the question people are asking in this thread.

        Since you seem to be continually avoiding it:

        Humans are burning fossil fuels and adding CO2 to the atmosphere. The natural environment (oceans and biosphere) is absorbing some of this CO2, but the remainder is accumulating in the atmosphere. Over the past 150 years or so, atmospheric CO2 has risen by over 100 ppm, to levels much higher than any seen in the previous 800,000 years.

        It is not purely coincidental that this rapid 35% increase in atmospheric CO2 — to a level far outside anything seen in the Pleistocene record — occurs at the exact same point when humans began adding large quantities of fossil carbon to the atmosphere.

        If someone asks “Are human CO2 emissions responsible for the observed increase in atmospheric CO2?”, the only reasonable answer is “Yes”.

      • “It is not purely coincidental that this rapid 35% increase in atmospheric CO2 — to a level far outside anything seen in the Pleistocene record — occurs at the exact same point when humans began adding large quantities of fossil carbon to the atmosphere.”

        So, now we have cum hoc ergo propter hoc to add to your mounting list of logical fallacies employed.

        Your mass balance argument is specious. It is, I am sorry but there is no way to sugarcoat this, dumb. Dumb as rocks. Dumb as toast. Dumb as… anything dumb every done.

        So, your whole case rest on a superficial resemblance between slightly quadratic trends in a particular time period (which can always be made to seem affinely similar through appropriate fitting) and an unshakable faith in a measurement process (ice cores) which can never be tested in closed loop fashion.

        You are skating on very thin ice, my friend.

      • J –
        It is not purely coincidental that this rapid 35% increase in atmospheric CO2 — to a level far outside anything seen in the Pleistocene record — occurs at the exact same point when humans began adding large quantities of fossil carbon to the atmosphere.

        So now you’re saying that correlation can be presumed to be causation? Really?

        Your statement “may” be true, but what evidence do you have – other than correlation? You keep on doing this – and it’s NOT science – it’s just an assumption based on correlation. Just because you can’t think of anything else it could be doesn’t make it so.

      • Just had another thought on this; though bear with me as i’m writing this in a hurry aas i need to get back to an experiemnt.

        Even if the system is a net absorber- it can still ‘present’ c02 into the atmosphere. Think of a pH buffer; there is a set amount of hydronium ions present to give that particular pH. Add more hydronium and the system adjusts to absorb those extra ions, but still presents the same amount to give the defined pH (until saturation- but that’s another point).

        Now if you change the temperature, the buffer-point also changes- which in turn presents more(or less) hydronium ions. Now if you add more external hydronium, the buffer system will still adjust to absorb those extra ions while allowing the net hydronium content (or pH) to rise as the temperature changes.

        I.e. although you are adding more hydronium ions, it is the temperature change that is driving the net rise in hydronium ions, not the external hydronium ion addition.

        I see this as directly analagous to the co2 / earths climate system.

        Though of course i could be 100% wrong- but it makes sense to me.

      • “The fact that anthropogenic emissions exceed the annual rise established beyond doubt that the natural environment is a net sink. ”

        Natural emissions exceed the annual rise by a much greater factor. Thus, using the same logic, this would establish beyond doubt that the anthropogenic environment is a net sink.

        We in fact see this, as atmospheric CO2 levels peak over areas where there are limited people and are least over areas where populations are greatest.

      • Your logic is faulty. You are forgetting natural uptake completely and it is the difference between natural uptake and natural emissions that governs the natural effect on atmospheric co2. Note anthropogenic uptake is essentially zero, we have not yet made serious attempts at sequestration.

      • so there is effectively zero uptake of anthropogenically emitted co2?? really? i find that hard to believe- thought it would certainly add weight to your argument if true. Do you have any evidence for this?? Besides the C12/C13 debacle?

        Also- damn, this thread is slow now.

      • Labmunkey: so there is effectively zero uptake of anthropogenically emitted co2?? really?

        No! dikran is not saying that at all. S/he’s saying that there is no anthropogenic uptake, not that there is no natural uptake of anthropogenic emissions.

        I’ll pedantically quibble with her/him and say that’s not entirely (though it is functionally) true. There is undoubtedly some small amount of sequestration due to reforestation in North America, for example, but this may well be swamped by deforestation elsewhere, and is certainly swamped by anthro emissions generally.

        The point is that if there were no sinks, anthro emissions are should be causing the atmospheric CO2 levels to increase more than they actually do. We know that the terrestrial biosphere and ocean are acting as sinks, however.

        As others have mentioned, this refutes Salby more or less entirely. We cannot be emitting more CO2 than is staying in the atmosphere, have nature acting on the balance as a sink, and magically have the increase in atmospheric CO2 be attributable to natural rather than anthropogenic emissions. It’s not exactly that cut and dry, but it’s pretty close.

      • “…this refutes Salby more or less entirely.”

        (Facepalm) see my comment above at August 6, 2011 at 3:24 am.

    • you are absolutely correct dikran,

      we know nature is aborbing more CO2 than it emits. Therefore it doesn’t explain the CO2 rise. The CO2 rise is caused by man, not nature.

      • Another example of that pristine science principle – “It must be humans because we can’t think of anything else it might be.”

      • I’m afraid you’re not getting the point.

        We know the mass of carbon emitted by humans (A). We know how much mass of carbon accumulates in the atmosphere each year (C). We know that A > C.

        Therefore, the carbon flux from “nature” (i.e., everything that is not people) has to be negative.

        We don’t know the magnitude of every single natural carbon source and sink, but that’s OK. By mass balance, we know the net natural flux is equal to the difference between A and C.

      • J
        Actually we do NOT KNOW the mas of human emitted CO2–we have very rough estimates–

      • We know the magnitude of the flux to within approximately 20%. That’s enough to conclude that it is larger than the atmospheric increase, and thus to conclude that the natural component of the earth system has to be a net sink, not a net source. See Ferdinand Engelbeen for details.

      • J

        Actually you are mistaken from what I have read on the topic. We do not fully understand the amount of natural variation, but there is strong evidence that it may be as large as human emissions. I previously posted a study showing that evidence from 2010.

      • I don’t know where you posted before. But interannual variation in the net flux from natural sources is small in comparison to the magnitude of the flux from anthropogenic sources. This can be seen by downloading the data from Mauna Loa or elsewhere, detrending it, calculating the standard deviation of the detrended data, and comparing that to the anthropogenic flux.

        Alternatively, just look at the keeling curve. It keeps rising steadily, through El Ninos and La Ninas, warm years and cold years. There’s small variations in the rate of increase, but it constantly increases.

      • 1)Its still very small – ppms.

        2)Extra CO2 is likely helpful towards extra life anyhow.

      • (1) is irrelevant. Lots of small things are important. Over time, the small annual increases have raised the atmospheric concentration of CO2 by around 35% or so. Whether that’s important or not depends on the role of CO2 in the climate system, not on whether “ppm is a really small number, dude”.

        (2) is likewise irrelevant to this thread. Whether CO2 is good, bad, or ugly is irrelevant to the question of whether it’s increasing, and whether combustion of fossil fuels and anthropogenic land use changes are responsible for most of that increase.

      • …or maybe CO2 at those levels is irrelevant. Compared to the other green house gases it’s are irrelevant. It’s like about one thousandth as important as water vapour is to warming.

      • “It’s like about one thousandth as important as water vapour is to warming.”

        More like a third as important.

      • lolwot, There is 40,000 ppm of water vapour (at the tropics where it is at a max concentrations) compared to 390 ppm CO2 in the air. The global average is 25 times more H2O vapour than CO2, but H20 is more effective as a green house gas. It amplifies the effect of other green house gases. The earth is warmest close to the surface. This is the most effective location for the greenhouse effect and that is where H20 vapour.

      • In a lot of places water vapor’s greenhouse gas effect is saturated. Did you forget that argument? it’s one of the skeptics favorites.

        Overall CO2 provides about a third of the greenhouse effect, not 1/1000th

      • J,

        What is your opinion on this presentation:

      • “We know that A > C.”

        No! You know A > C – D! A > C does not follow!

      • As the other part doesn’t allow further comments, here is mine:

        “But, your little algebra says nothing about the relative size of C and A-B! C could be 1,000,000,000,000,000,000 times larger than A-B, and you have no way of knowing it! D could totally remove A-B with hardly a flicker of acknowledgement, and still fall behind in keeping up with C. You. Do. Not. Know. ”

        The basic formula in question is:
        E = (A – B) + (C – D)
        where E is the increase in the atmosphere and A,B resp. human emissions and sinks and C,D natural sources and sinks.

        We know E (measured), we know A-B (calculated), therefore we know C-D.
        Over the past 50 years of accurate measurements, C-D was always negative, see:

        Thus whatever the real height of C and D, D was always larger than C. For each year, the exact difference between C and D is known. If for the current year the emissions are 8 GtC, the increase in the atmosphere is 3 GtC, then the difference between C and D is -5 GtC.

        It doesn’t make any difference if C was 100, 1,000 or 1,000,000 GtC, as in all these cases C-D = – 5 GtC
        For C = 100; D = 105
        For C = 1,000; D = 1005
        For C = 1,000,000; D = 1,000,005

        Thus the absolute height of C and D is not of the slightest interest at all for the mass balance and for the fact that humans are fully responsible for the increase. No matter how much natural CO2 circulates through the atmosphere, in all cases nature is a net sink and doesn’t contribute to the increase.

      • Nature is a net sink because of the anthropogenic input. The anthropogenic input is removed to restore the equilibrium. Without the anthropogenic input, the net sink would be a net source.

        When it starts cooling, the net non-anthropogenic flux (sink since the ~1960s) will increase. (C – D) will get more negative and when absolute value of (C – D) is greater than (A – B), the E will get negative.

        (A – B) does not drive E

        Temperature drives E.

        (A – B) drives (C – D). E is determined by the temperature.

      • I think, Edim, you are saying what I am saying in different words just below. Will they get it? I’d bet against it. Oh, well… We tried.

      • Edim, you are in part right. But it depends:

        In the past 50 (and probably longer) years, (C-D) is negative, that is what is observed. That means that the increase of E is fully attributable to (A-B). Temperature modulates how negative (C-D) is, but over the full 50 years, it was never positive. Thus temperature modulates the sink rate by nature, therefore the increase rate of E, but the trend is (near) 100% from (A-B). Only if temperature has a more permanent increase, that contributes to E. But that is at maximum 8 ppmv since the LIA.

        If the temperature gets more and more negative, one need a continuous drop of about 0.25 degr.C per year (!) to completely absorb the (current) emissions.

      • Nooooooooo!!!

        I see I am going to have to talk about this from a systems aspect, something I wanted to avoid because, frankly, I’m not sure who here will understand it.

        D IS NOT independent of A+B. The natural structure of systems such as this is as follows. Let S be the accumulation,

        S(k) = S(k-1) + E(k)

        where “k” refers to the year. D is an ARMA operator on S, so that

        S(k) = S(k-1) + A(k) – B(k) + C(k) – D(S(k))

        In the simplest form, D might be represented by a simple gain. Let that gain be “d”

        S(k) = S(k-1) + A(k) – B(k) + C(k) – d*S(k)

        Because this is a linear system, you can break it up into three parts S1, S2 and S3, where

        S1(k) = (1-d)*S1(k-1) + A(k) – B(k)

        S2(k) = (1-d)*S2(k-1) + C(k)

        S3(k) = (1-d)*S3(k-1)

        S1 is the accumulation due to A and B, S2 to C. These are initialized to zero at time step k = 0, and S3 is initialized to S(0). Then, S(k) = S1(k) + S2(k) + S3(k) for all k >= 0.

        If A(k) – B(k) is bounded to be less than a value, say “M”, for the time period under scrutiny, then we can bound S1(k) as S1(k) <= M/d. If d is really large compared to M, then S1 is going to be really small.

        But, that DOES NOT MEAN S2(k) is small, because we do not know what C(k) is!

        This static accounting you guys have been doing is simply not up to the task. You have made a conclusion which is in NO WAY justified.

      • Bart, D is hardly dependent of (A-B), it is (C-D) which depends on sigma(E):

        As it looks like that the CO2 cycle of the atmosphere acts as a simple linear first order process, the sink rate (C-D) directly depends of the difference between the current level in the atmosphere (390+ ppmv) and the equilibrium setpoint (around 290 ppmv). As (C-D) is about 4 GtC/year, the influence is distributed over the sources (only the oceans, as volcanoes and vegetation decay don’t react on pressure changes) and sinks (oceans and vegetation). Oceans emit about 90 GtC over one season, thus D may have been reduced with a few %. That is all.

      • Ferdinand Engelbeen | August 6, 2011 at 8:22 am |

        “Bart, D is hardly dependent of (A-B), it is (C-D) which depends on sigma(E):”

        Bssst… Wrong. The sinks do not know the difference between anthropogenic and non-anthropogenic CO2 (ACO2 and NACO2). They expand for all inputs. That means D can be broken up into two parts: D1, which is the sunk ACO2, and D2 which is the sunk NACO2. So, the question is NOT is (A-B) > (C-D), but is (A-B-D1) > (C-D2).

      • “If A(k) – B(k) is bounded to be less than a value, say “M”, for the time period under scrutiny, then we can bound S1(k) as S1(k) 0, or to put it in your terms, C(k) – d*S(k) > 0. And since we know S(k), A(k), B(k), from direct measurement, and since d in your equations is determinable from the above, we can also determine that C(k) – d*S(k) <0. So Salby is wrong.

      • We also know that both C and D are very much larger than both A and B, therefore a small change in either C or D will have the same effect as a large change in A or B.
        How then, especially given factors like deforestation, desertification etc, do you imagine that the value of C-D has remained stable enough, even over the last century, to make A-B the dominant player?

      • Let’s forget about the notation A, B, etc. via which I apparently made this thread less clear rather than more clear, by using different sets of letters in different comments. I wish I hadn’t started that.

        It’s easy to see that today (and for several decades now) anthropogenic emissions account for the entirety of the observed rise in CO2.

        Two hundred years ago, when humans were first starting to burn fossil fuels, natural variations in CO2 fluxes would have resulted in increases or decreases in atmospheric CO2 that dwarfed the impact of those small, early human emissions.

        At some point between 1800 and 1960, a point was crossed over whereby anthropogenic emissions became large enough to produce an ever-increasing accumulation of CO2 in the atmosphere. I’m not sure exactly when that crossover occurred, but we’re long past it now.

      • We have only rough figures pre-Mauna Loa, but we know that the variability in the past 50 years of (C-D) are quite modest: +/- 2 GtC (+/- 1 ppmv) around the trend. Thus in the earlier period, when emissions were less than 2 GtC/year, it may have been that nature was a contributor to the increase, or a sink for all human emissions, but in average a sink.

        Thus while there may have been huge changes in individual flows, the variability in sink rate is surprisingly small for a natural process (about 2% of the throughput). The main reason of the low variability may be that oceans and biosphere act as CO2 opponents on temperature changes

      • The main reason of the low variability may be that oceans and biosphere act as CO2 opponents on temperature changes

        Having no desire to live on either Snowball Earth nor Jurassic Park, I’m personally grateful for this low natural variability!

      • You guys do not understand feedback systems. I’m looking at you two like a parent looks at an errant teenager who thinks he knows all about the world, but is unaware of the gaping holes in his logic due to his inexperience. You don’t even realize how foolish you look.

      • J,

        Two hundred years ago, when humans were first starting to burn fossil fuels, natural variations in CO2 fluxes would have resulted in increases or decreases in atmospheric CO2 that dwarfed the impact of those small, early human emissions.

        But these huge natural variations somehow self-regulated so as to keep CO2 concentrations within close limits for millions of years?
        And then, at some point halfway through the 20th C, these huge natural variations suddenly and coincidentally stopped, did they?
        I see.

      • Ferdinand:

        The main reason of the low variability may be that oceans and biosphere act as CO2 opponents on temperature changes

        Ferdinand, it’s simply not enough to say ‘may be’.
        Unless you can satisfactorily explain such processes, any assumptions you may make will remain just so – assumptions.

      • Bart writes:

        “We know that A > C.”

        No! You know A > C – D! A > C does not follow!

        You’re getting overexcited and misreading things. Admittedly, it’s partly my fault for being sloppy.

        The comment you reply to here was posted by me at 11:35 am, and does not use any term “D”. It was just an ultra-simplified statement that human emissions (A) are greater than the observed atmospheric increase (C).

        That’s just a fact.

        Now, later (at 3:52 pm) I responded to a post by someone else, and it seemed necessary to break things down a little more, so I posted a different comment involving five terms (A, B, C, D, E). Due to the semi-threaded nature of this comments list, that later comment actually appears higher up on the page. So if you’re reading this from top to bottom, and not paying too close attention, it’s very easy to understand why you might be confused.

      • I understand the setup perfectly well, J. It is mind-numbingly clear that you do not.

      • Bart, I have to reply here, as I can’t on the right place.

        Bart | August 6, 2011 at 12:31 pm | :
        “The sinks do not know the difference between anthropogenic and non-anthropogenic CO2”.

        I didn’t say or implied such thing, to the contrary. For any equilibrium reaction the sink rate is directly dependent of the difference in partial pressure between current CO2 and equilibrium CO2. The sink rate is independent of the origin of the molecules.

        I don’t see any need to split D. The sink rate is not D (that is the total sink and largely unknown and not of interest here). The sink rate is (C-D), that is the net amount which is removed (and exactly known). That is all what is needed and all what counts. It is the height of (C-D) which depends of the partial pressure difference.

        Bart | August 6, 2011 at 12:34 pm |

        “You guys do not understand feedback systems.”

        Wow, 34 years experience with feedback systems in chemical plants (including a few nasty runaway reactions) don’t count?

      • “Wow, 34 years experience with feedback systems in chemical plants (including a few nasty runaway reactions) don’t count?”

        I don’t know what you do that you call “feedback”, but you are making an incredibly elementary mistake here, regardless. Your mass balance rules out nothing. Let’s work through an example. I’m not saying this is how CO2 is accumulated in the atmosphere, it is merely to show that your assumption is unfounded in general. Let’s work with the hypothetical model I gave in my comment at August 6, 2011 at 7:37 am

        S(k) = S(k-1) + A(k) – B(k) + C(k) – d*S(k-1)

        (Note: I typed hastily and the sink term should have been written as being evaluated at step k-1)

        Suppose at year 0, we have S(0) = 280 ppmv.

        At time step k = 100, we have S(100) = 380 ppmv. Let’s ignore the B(k) term for this example (there are no active measures being taken by humans to remove CO2) Suppose A(k) = 0.04*k ppmv/year. A straight accumulation

        S(k) = S(k-1) + A(k)

        would give S(100) = 280 + 0.04*100*101/2 = 481, i.e., the total accumulation would be twice what is observed.

        Now, assume d = 0.8. Without considering NA inputs, we have

        S(k) = S(k-1) + A(k) – 0.8*S(k-1)

        At the end of the period, we have S(100) = 12.5 ppmv (obviously, we’re missing the big chunk due to NA forcing).

        Now, add in the NA intput. Suppose C(k) = 214+0.8*k. We have

        S(k) = S(k-1) + (A(k) + C(k) – 0.8*S(k-1))

        We now get S(100) = 380 ppmv, as observed. The ACO2 input flux A(k) is much smaller than the NACO2 input flux C(k), but the outcome is less than the total accumulation of A(k). Yet, you have assured us that this cannot happen!

        In 91 of 100 years, C-D = C(k) – 0.8*S(k-1) is, indeed, negative. It is a net “sink” by your definition. Yet, clearly, C(k) is the quantity driving the major portion of the output. How can this be???

        I know your next move will be to huff and puff and say this is not representative of how the actual system works. But, in a very general sense, it is. In any case, that is an argument for another day. First, you folks have to understand that the argument you are making requires A LOT more supporting evidence, which constrains the system favorably for you (but which isn’t allowed because the system would have secondary characteristics that have not been observed), than you have so far believed or proferred.

      • That makes sense to me as described.

        Effectively there is an equilibrium CO2 level being increased naturally. Actual CO2 level must follow that rising equilibrium level. As a result CO2 rises at rate N independently of how much CO2 humans are emitting.

        When humans are emitting > N (as they are today) then nature turns into a sink absorbing the excess.

        If humans suddenly start emitting < N then nature turns into a source emitting the shortfall.

        At all stages the CO2 level rises at rate N independently of whether humans are emitting or not.

      • Paleoclimate suggest that the natural rate of change of CO2 is negative, except for volcanically active periods (which we are not in). It appears to be about 10 ppm per million years. This is probably the sequestering rate due to weathering and vegetation.

      • So in essence, even though human CO2 emissions are greater than the rate of CO2 increase in the atmosphere and nature is a net sink, if human CO2 emissions were to stop, CO2 would continue increasing in the atmosphere at the same rate because nature would change to becoming a net source.

      • The format of this blog makes replies quite difficult…

        Bart | August 6, 2011 at 10:03 pm |

        S(k) = S(k-1) + A(k) – B(k) + C(k) – d*S(k-1)
        S(k) = S(k-1) + A(k) – 0.8*S(k-1)

        You assume here that the total natural sink is directly proportional to the amount in the atmosphere. That is a bridge too far. When the system was in equilibrium, then C = D = d*S(k-1) where d is about 0.26 for 580 GtC in the atmosphere (if we may assume that the current knowledge of the carbon flow of around 150 GtC source/sink flow is correct).

        Now that S increased with over 30%, d decreased to 0.19 for 800 GtC in the atmosphere, if we attribute the total increase in sink rate (4 GtC/year) to the sink. D is simply independent of the amount of CO2 in the atmosphere. There are no indications that the natural flows changed by 30% because of the increase in the atmosphere.

        There is hardly any change in C or D from the increase in the atmosphere, and there is little difference between C and D because of that. Instead, the sink rate, the difference between C and D, is a linear response to the increase in the atmosphere:
        S(k) = S(k-1) + A(k) + (C-D)(k)
        (C-D)(k) = d*(S(k)-So)
        S(k) = S(k-1) + A(k) + d*(S(k)-So)
        where So is S at equilibrium conditions and d about 0.04 GtC/ppmv difference.

        Of course, even a small non-human caused change in C or D changes the balance and may dwarf the human contribution. But there is no need to guess what the imbalance (C-D) is, because we know that quite exactly. And that was always negative in the past 50 years at about halve the human emissions…

      • lolwot | August 6, 2011 at 11:40 pm |

        Effectively there is an equilibrium CO2 level being increased naturally.

        After 800,000 years of ice cores knowledge, we know that the natural equilibrium was 290 ppmv at the current temperature.

        When humans are emitting > N (as they are today) then nature turns into a sink absorbing the excess.

        In this case you assume that 100% of the human emissions are instantly absorbed and the increase is only from the increasing setpoint. That means that the sensitivity of CO2 for temperature is about 100 ppmv/degr.C, which leads to negative values during ice ages and extreme high values during warmer periods in interglacials. Even if you don’t trust ice cores, the first is impossible, the second is not observed in any kind of proxy. The extreme high sensitivity is impossible.

      • Ferdinand,
        Your formula and that of Bart are equivalent. Your disagreement with Bart is due to a misunderstanding of his formula. He has made the formula as simple as possible by rearranging different phenomena appropriately in C and D.

      • Ferdinand Engelbeen | August 7, 2011 at 6:21 am |

        “There is hardly any change in C or D from the increase in the atmosphere, and there is little difference between C and D because of that. “

        A statement like this is what makes me doubt your “feedback” cred. You do not understand how natural systems work. In a system such as you describe, no equilibrium would exist.

      • Pekka Pirilä | August 7, 2011 at 6:42 am |

        Your formula and that of Bart are equivalent.”

        Indeed, they are (or would be, if he got the sign of the feedback right – currently, his equation is unstable). Ferdinand does not realize his equation is in conflict with his words.

      • Sorry for the delay in reply, three blogs to respond to and a life beyond the blogosphere sometimes a little too much…

        First, I need to go back to what Pekka wrote August 4 at 4:45:

        1. An alternative source of CO2 adding CO2 on top of the carbon flux that has maintained the balance.
        2. Strong sinks that absorb both half the human emissions and the additional source.

        But in fact that doesn’t alter the mass balance, because the strong sinks and the alternative source together only add to the turnover, don’t add anything to the mass balance. The balance still is that natural sinks are greater than natural sources.

        Bart’s example is similar, but his interpretation is different:
        He says:
        The ACO2 input flux A(k) is much smaller than the NACO2 input flux C(k), but the outcome is less than the total accumulation of A(k). Yet, you have assured us that this cannot happen!
        That the outcome is less than the total accumulation has nothing to do with the height of C(k), that only depends of the difference between C(k) and d*S(k-1). The difference must be negative over the years, thus a sink measured over the full period, only then is it possible that the outcome is less than the accumulated A(k). Again, all of the height of C(k) is only throughput, except for 9 years in Bart’s example.

        Nobody said that C(k) is not the majority of the output, to the contrary, but in most cases more than the output disappears in the sinks.

        Further, there is a fundamental difference between Bart’s model and my model: Bart’s model in principle can go down to zero CO2, because there are no constraints, while my formula is linear around a (temperature controlled) setpoint.

        And from a practical view: we don’t know the exact height of C or D, but we know (for the past 50 years) that (C-D) = 0.55*A +/- 2 GtC. Thus whatever the height, there is (relative) little difference between C and D.

        But thanks for the remark that it must be – d*(S(k)-So), I indeed forgot to change the sign after copying and replacing.

      • Ferdinand,

        It should be clear from earlier messages that I don’t agree with Bart on the conclusions related the real Earth system, but I prefer having also the logic right and mathematics correctly understood, not only the conclusions.

        Bart prposed a linearized model that can be right only over a limited range close to the present state of the Earth system. Thus the term d*S(k-1) is also valid only for S(k-1) not far from the present value or from the value S0 that you introduced.


        D = d*S(k-1) = d*(S(k-1)-S0) + d*S0

        this term is split to two terms. The first is the one that you prefer and the second is a constant that can be included in C (i.e. C = C1 + d*S0, where C1 is the natural source excluding the contribution of the mathematical trick). That’s what Bart did. That’s just a mathematical trick that makes the formula slightly simpler, while it can lead to such a misunderstanding that you appear to have concerning his message.

        The division of the natural term to C and D is done on the basis that D is proportional to S(k-1), not on the basis that it would have all the sinks. C may include both sources and sinks but they are assumed to be determined by something else than S(k-1). Large (i.e. close to 1.0) coefficient d would mean that any additional CO2 due to human influence or some natural process independent of S(k-1) would be removed to a large extent from the atmosphere. As we know that S(k)-S(k-1) is as large as measured at Mauna Loa large d would require a large natural source C1 on top of the constant “trick term” d*S0. That’s a mathematically valid possibility, while it’s not physically plausible taking into account everything else that we know about CO2 in the Earth system.

      • “there is a fundamental difference between Bart’s model and my model”

        There is no difference at all, except that you take “So” to be a constant, and I assume it is time varying. Indeed, it is how I came up with the equation, knowing that S(k) would track “So” when the feedback parameter is “fast”.

        You can protest all you like about how realistic the model is but, as Pekka observed, it all comes down to whether the feedback is fast enough. I maintain that, if the ice core data are truthful, it follows that it must be, because otherwise there would not have been strong regulation of the CO2 level in the past.

        But, this is beside the point here. The point here is that I have ripped your mass balance argument to shreds. Your claim was that the mass balance proved that the rise was wholly anthropogenic. That claim is revealed as sloppy reasoning and utterly false.

      • Pekka Pirilä | August 9, 2011 at 5:13 pm |

        “That’s a mathematically valid possibility, while it’s not physically plausible taking into account everything else that we know about CO2 in the Earth system.”

        On the other hand, it is not physically possible for CO2 to have been regulated tightly in accordance with the ice cores without strong feedback. So, you have something which you believe is not physically plausible versus something which is not physically possible. Who wins that contest?

      • Bart,

        Time scales are essential. In the present case the feedback should be strong over a timescale of years, while the ice cores tell about slower processes.

        In the present situation both the large natural source and the mechanism for the very strong feedback are missing. We have just the human contribution and the feedback that is sufficient to compensate for about 50% of the annual human contribution. From the understanding of the feedback mechanisms it could be perhaps 50% stronger, but we miss the source for even that.

      • Pekka – absence of evidence is not evidence of absence. It is a simple discrepancy which must be laid to rest, or there is no way to conclude anything about the system: how were CO2 levels maintained in a tight range over centuries, given all the random influx and egress from volcanic activity, environmental perturbations, deforestation, desertification, fossilization, agricultural trends, wars, oceanic turnover, continental drift, weathering of minerals, fires, floods, etc…, if there is not a fairly strong feedback holding them in place?

        If there is not a strong feedback holding them in place, the ice core measurements are bunk, and we have no basis for believing current levels are unusual. If there is a strong feedback holding them in place, then the current rise is not anthropogenic in origin.

        The CO2 narrative sought to establish a scenario by which the rise could be attributed to human emissions. But, the narrative is internally inconsistent.

      • On Bart | August 6, 2011 at 10:03 pm |

        Just in case anyone tried to replicate my math in the above post, I noticed that in the actual script I ran, I had set A(k) = 0.1*k ppmv/year rather than A(k) = 0.04*k ppmv/year.

      • Bart,

        Pekka – absence of evidence is not evidence of absence.

        Formally you are right, but the observed increase in atmospheric CO2 has been very regular at a level that cannot have continued for very long. The strength and regularity of that increase requires something that’s really, really exceptional in comparison with earlier history. The human influence fits the requirement, while inventing something natural to do the same is really, really unlikely.

        The case for the human dominance is really, really strong.

      • “…at a level that cannot have continued for very long.”

        Cannot? This sounds like a personal inclination rather than an iron law to me.

        The strength and regularity of that increase requires something that’s really, really exceptional in comparison with earlier history.”

        Assuming the ice core measurements accurately reflect history. And, what you mean, of course, is in relatively recent “earlier” history. Yet, the ice core measurements also indicate a level of stability which is in conflict with the assertion of substantial human influence.

        “The human influence fits the requirement…”

        On a superficial level. The stress hypothesis also fit the requirement for inducing stomach ulcers. The theory of continental drift was rejected for decades because there was no known driving force.

        Too much of climate theory is being based on data which are not nearly as incontrovertible as portrayed. Too many reasonable possibilities are being rejected out of hand on the basis of limited information.

      • “…at a level that cannot have continued for very long.”

        Cannot? This sounds like a personal inclination rather than an iron law to me.

        Negative concentrations are not possible and it’s possible to set lower limits limits well above zero.

      • “Negative concentrations are not possible and it’s possible to set lower limits limits well above zero.”

        But, you’re claiming upper limits.

      • I was referring to history. It’s not possible that the trend has continued for very long in the past at the present rate.

      • I see. Then, I guess I see your assumption that it is “very, very unlikely” as just that: an assumption. Do you have anything to go on other than a vague sort of feeling?

        It all comes back to the ice core measurements. They make you believe that everything was quiescent for centuries before. Yet, it is “very, very unlikely” that, that quiescence was just happenstance, and almost surely because there were opposing forces and feedbacks maintaining it. And, if that is the case, then there was an abrupt change either way you slice it: either there was some sort of burp in the system which altered the equilibrium conditions, or there was a relaxation of feedback which allowed the anthropogenic influx to accumulate. Which is more likely? An sudden addition into the system (perhaps from upwelling of the deep oceans), or a massive failure of part of it?

        Of course, the simplest explanation is that the ice core measurements are unreliable, and I suspect that is likely enough, given that there is no way to actually confirm the model for how CO2 is trapped and held over centuries, much less many thousands of years, in an end-to-end fashion. But, the simplest explanation is not necessarily the right one.

      • Ferdinand Engelbeen

        I am, oh horror, computer handicapped for the moment, at last I now have a laptop with Excel on board but with a Belgian/French keyboard (azerty), which I am not familiar with.

        Thanks for the clear explanation Pekka. I have done more practical work than theoretical, so theory is mainly from 40+ years ago, but it is slowly coming back. Thus my formula and Bart’s are more or less equivalent. Rests the main objection:

        I have repeated Bart’s calculation. His main point is that the increase in the atmosphere is mainly from natural emissions, as these are much larger than from human emissions. My objection is that it doesn’t matter, because as long as the natural sinks are larger than the natural sources, whatever the height of the sources, these are only part of the throughput and don’t add to the increase (as is the case in Bart’s example). Before Bart goes through the roof in anger, let us look at the most extreme case in Bart’s example:

        All human emissions are completely absorbed within minutes by the nearby forests or oceans. That makes no difference for the flow of natural sources, but that occupies part of the natural sinks, which otherwise would be used by natural CO2.

        Thus the formula then will be:
        S(k) = S(k-1) + (A(k) – D1(k)) + C(k) – D2(k)
        where A(k) – D1(k) = 0 and total natural sinks D = D1 + D2

        We measure C(k) – D2(k) in the atmosphere, and the result is that C(k) is larger than D2(k), in quantity about A(k)/2.
        Thus in this case the natural emissions C(k) are 100% responsible for the momentary increase in the atmosphere. But that is a false responsability, because the human emissions reduced the sink capacity of the natural sinks, so that a part of the natural emissions remain in the atmosphere. Ultimately, all what happened is that the anthro CO2 was replaced by natural CO2, but the origin of the increase is the reduction in natural sinks by human CO2, not an increase of natural CO2. Only when the difference between C(k) and D(k) gets larger than A(k), only then there is a real contribution by natural CO2.

        Our mass balance argument still stands strong.

        Next message some comment on the response speed.

      • Ferdinand Engelbeen | August 11, 2011 at 6:39 am |

        Ferdinand – All you are saying, in roundabout fashion, is that, in equilibrium with a purely intregrating system, the anthropogenic input is responsible for any rise. You have dismissed the role of feedback entirely and, in doing so, are insisting on a tautology for how your system so constrained will behave.

        But, the constraint is arbitrary, and the system you describe is merely one out of infinite possibilities. We can partition that set of possibilities into two subsets: fast systems (high bandwidth) and slow systems (low bandwidth).

        Your purely integrating model falls in the slow set – it is the ne plus ultra of the slow set. Your mass balance argument is really just a correlation which applies to systems in the slow set. It is not a characteristic of the fast set.

        It is my contention that the quiescence of CO2 levels, as indicated by the ice core data, indicates that the CO2 regulatory system is a fast one. The reason is that slow system inherently cannot maintain tight bounds on the system output, which would necessarily display random fluctuations similar to a random walk over time lines associated with the settling time of the system.

        But, the bottom line is, your mass balance argument fails. It has a crucial “IF” condition which you have left out, to wit: IF the system is slow, THEN (and only then) the mass balance proves that the rise is anthropogenic.

        Hope that clears things up for you.

      • Ferdinand Engelbeen

        Bart, depends what you call “fast” and “slow”.

        The feedback of the CO2 in the ocean’s surface and vegetation on temperature certainly can be called fast (1 to a few years), but limited. The reaction of both on CO2 changes also is fast, but limited for CO2 disturbances: about 20% of the emissions/year for vegetation and only 5% of the emissions/year in the ocean’s surface, due to ocean chemistry.

        The deep oceans take the rest of the 50% of the sink rate, which all together gives a half life decay time for an excess amount of CO2 of about 40 years.

        That is slow on human scale, but pretty fast on geological scale, the more that many of the other natural processes are much slower, or much smaller in scale or both.

        – Volcanoes and vents emit less than 1% of human emissions (even the Pinatubo eruption caused a dip in the CO2 increase, as the cooling by the volcanic dust increased the absorption of the oceans beyond the extra emissions.
        – The current increase in the atmosphere is equivalent to burning down about 1/3rd of all land plants. You need to burn a lot of vegetation to give a descernable increase in the (ice or other) records, the more that fresh growth within the following years rapidely uses a lot of CO2.
        – Other processes are very slow in change: vegetation area increase/decrease, ocean overturning rate, rock weathering,..

        Thus the response to CO2 disturbances is slow enough to support the mass balance argument and fast enough to support the stability as seen in the ice cores.

      • Well, at least maybe you’re starting to get it now, that the mass balance “argument” is really not an argument at all, but an assertion of the type of system we are dealing with.

      • No Jim, the mass balance argument rules out the possibility of the rise being of natural origin. It isn’t that we can’t think of anything else, we can rule out the possibility as being inconsistent with the observations. On the other hand, we know anthropogenic emissions are more than enough to explain all of the observed rise (and then some). So if it isn’t natural, and it isn’t anthropogenic, what else could be causing the rise, UFOs?

      • dikranmarsupial –
        I understand mass balance. I also understand the constraints on mass balance – about which you make “assumptions”. I also understand that the carbon cycle is still an unknown and will remain so for some time to come. Why else would you think the OCO spacecraft was important?

        IOW, come back with your arguments when you actually have the cycle AND ALL the sources/sinks in the known column. And you don’t have that right now. Therefore – your logic works IF and ONLY IF all your assumptions are correct. The fact that you “can’t think of any other sources” was the thrust of my previous comment. And while you may be correct, but that has yet to be determined.

        So – your logic is provisional if not uncertain.

        BTW – I did not say you’re wrong – or that CO2 is not increasing – or that humans have no part in the process. I AM saying that I see a LOT of assumptions that may be intuitive to you, but “intuitive” is only one part of science. The important part is the title of a book – “But is it True?” And too often, it’s not.

        Science is about determining whether it is – or is NOT – true. Which is why the massive opposition to the Salby paper – before anyone has even read it – is NOT science but advocacy. And ridiculous.

        Personally, I’m hopeful, but sceptical. Meaning – IF it’s true, it would scratch “my” confirmation bias – but I have doubts.

      • Jim, as explained just above here, you don’t need the exact figures for any natural CO2 input and output, because you know the result at the end of the year. The difference between two knowns is a known. And that difference was negative over the past 50 years. Thus nature can’t be the cause of the increase in the atmosphere, it is a net sink.

        Thus even without a look at Salby’s paper, he made a fundamental error on this point.

      • wrong, wrong, wrong, wrong, wrong… See above @ August 6, 2011 at 7:37 am.

      • Ferdinand –
        I think I’ll wait for the paper.

      • “…the mass balance argument rules out the possibility of the rise being of natural origin.”

        No! See above @ August 6, 2011 at 7:37 am.

    • Not necessarily, take this hypothetical to explain the arithmetic. Partition the system into anthropogenic, sea (natural) & land (natural) i.e. divide natural into sea and land. Over a given period, if : –
      1. Net anthropogenic emission = +1 unit
      2. Net sea emission = +1 unit
      3. Net land emission = -1.5 unit

      The overall net emission over this period = + 0.5 units yet we can see how anthropogenic and sea (e.g. warming) contribute equally to this figure while net natural emission (i.e. sea + land) is – 0.5
      Do we really know enough about the carbon cycle, in particular the natural fluxes of CO2, to rule out that some thing like this is going on?

      • If the question is “is the rise natural or anthropogenic” then the internal partitioning of the natural sources and sinks is irrelevant. Of course some parts of the natural carbon cycle are net sources (e.g. volcanos), but considering them separately just makes what is left of the natural carbon cycle and even stronger net sink. In your hypothetical example, what would happen if anthropogenic emissions were reduced to zero? Atmospheric CO2 would be falling instead of rising.

      • You are correct when you say. “In your hypothetical example, what would happen if anthropogenic emissions were reduced to zero? Atmospheric CO2 would be falling instead of rising”.
        However in my hypothetical example what would happen if if sea emissions over time were reduced to zero? e.g cooling of the oceans. Then CO2 would also be falling even though anthropogenic emissions are rising. Actually I would contend that in both cases the CO2 would remain the same because the net land absorption would probably decrease by 0.5 units.
        The point here is that it’s an error to view the natural sources and sinks as one homogeneous system. They are not, they can behave independently over time but obviously the situation is far more complex than a simple partitioning of natural into sea and land..

  36. The isotopic argument never made any sense to me. Here’s why:

    Basic thermo: there exists a theoretical state called equilibrium, which when talking about the CO2-Water system depends on temperature. Anybody who’s ever opened a warm can of soda understands that CO2 pressure goes way up with rising temperature.

    So it’s completely uncontroversial that rising ocean temperature will raise the equilibrium CO2 concentration.

    A consequence of bacis thermo, Le Chatelier’s Principle, says that if you push CO2 into this system, equilibrium will be shifted slightly, but most of the CO2 will disappear from the gas phase. Again, this is very basic stuff.

    We also know the following (h/t Thinking Scientist):

    So what does the isotopic ratio tell us that we don’t already know? We already know the fluxes, and the isotopic composition tells us something about the transport processes, but the equilibrium is what it is. If, indeed the equilibrium is being shifted by the temperature, the isotopic composition doesn’t shine any light on that process; only the transport processes involved.

    If, in fact this turns out to be valid, it implies a very low climate sensitivity to CO2, although it also implies another positive feedback mechanism. So in reality, we could be seeing more natural CO2 than anthro, and yet the anthro could be leveraging some of the natural CO2. So it’s not at all clear what this implies for sensitivity to anthro carbon. This theory could end up incorporated into AGW theory without disturbing it.

    • The isotopic ratios tell you something about the source of the CO2. See, for example, Ferdinands blog or real climate cited herein or look at this summary

      and yes, evaporation is very slightly higher for heavier isotopes, but the differences btw C12/C13 are ppm anyhow.

  37. Fred,

    I have always respected you and your insight, but you are giving this blog too much credibility; this is another of Judith’s whole charade of “this is interesting! Maybe I will put it on my blog and reserve judgment to avoid any criticism of myself, but pretend it has validity.”

    I pointed this out with Loehle’s piece too. It is a dumb game she plays and everyone else sees it.

    • Chris,

      It’s always possible that she will break down and actually answer straightforward requests like that posted at:

      She might surprise you and actually go on the record as to why this is “wow”-worthy, “sufficiently important”, etc.

    • Latimer Alder

      Could you explain to an interested layman why this isn’t interesting to you? Seems to be extremely interesting to me.

    • What’s the alternative, Chris? To pretend it doesn’t have validity? Listen to the podcast and you will learn why people think Salby has blown a hole in the isotopes argument. Salby’s work has not been replicated yet, so Dr. Curry can’t totally embrace it. But it is interesting to anyone who has an open and questioning scientific mind. Too bad that excludes many climate scientists.

    • Chris,
      Hearing a first year grad student talk about a real scientist’s charade, on her own blog site, is rude even for you.
      You manage to squeeze in ‘charade’ and ‘pretend’ regarding Dr. Curry’s motives all in one paragraph, and follow it with characterizing her as ‘dumb’ in the next.
      Nothing acts as a ‘tell’ of someone dodging an issue much better than to impugn their motives and sincerity.

      • hunter,

        I’m sorry if it is “rude” but Judith Curry is a publishing climate scientist. She has a PhD. She is in a in a position to make judgments on various claims, and she also influences a lot of peoples opinions based on her credentials. There is no excuse for over-hyping every new opinion out there. It also takes much less than a grad student in the field to spot some of the bad work recently discussed on this blog (but believe it or not, even without a PhD, we do actually pay tuition for a reason).

        The evidence CO2 increase is due to humans is overwhelming. The isotopic signature discussed in Dr. Steig’s link is but one. So is the oxygen decline in the atmosphere. The carbon uptake by the ocean and land is another proof that they are not acting as long-term sources. The point made in the video that the CO2 is “dynamic” and influenced by many processes- temperatures, clouds, etc may be true but is not the least bit convincing in the context of the long term trend. CO2 has fluctuated between ~180-280 ppm over the last million years and done so at considerably slow rates. The feedback influence from temperature is on the order of 10 ppm per degree (if pressed, I will find a reference, there was a good one a couple years ago but I forgot the name). In contrast, CO2 has risen ~100 ppm in ~1 century and at absolute concentrations much higher than in the Quaternary. Did the clouds suddenly shift into a completely new regime so as to create this rise? Was the trend from 0 to 0.8 C anomaly causing the ~100 ppm CO2 increase; if so, the sensitivity of CO2 concentrations to past conditions would be much, much higher.

        I am tired of people treating every new idea as if it is really a big deal, ONLY because it has something to say against “AGW.”

      • Chris,
        I am tired of sophomoric (look it up) behavior from people like you.
        The evidence is not overwhelming. It is strong. Nor is the evidence that CO2 is the primary forcing of the climate.
        Your side has never explained the clear lag between increased temps and CO2 increases in the historical record.
        As to the paleo record, the only thing clear is that it has huge error bars, iss full of noise and is not complete or reliable.
        What I and many skeptics are tired of is being treated rudely, of seeing people like Dr. Curry or Spencer or Pielke treated shabbily, of skeptics being told we are mentally or genetically deficient, or that we are actually crypto-nazi deniers.
        This idea, if true, is in fact huge because it would be yet another line of evidence that the AGW movement has been leading us down a rabbit trail.
        we already know that flood, storm, droughts are not impacted significantly, in contra to AGW beliefs. If we can determine how much of the increase in CO2 is simply driven by the slight warming we have experienced, then we can, happily conclude that even less of the hysteria and fear mongering of your profession is something to worry about.
        Already 69% of Americans believe that climate scientists are committing fraud. I would suggest that your behavior at the bottom food chain, and Dr. Steig’s at the top, only increase that percentage.

      • Hunter, someday when you get your GED and really buckle down to basic math and introductory science, you may be able to pull off this sneering superior act. As it is, though, your painful insecurity and overpowering (and justified) feelings of inferiority scream out of every snide, whiny, rude remark.

        You “skeptics” have murdered dozens, compared scientists to Nazis, threatened to rape children and waved nooses in scientists’ faces. Your hypocritical concern with the “rudeness” of people calling you out on your incompetence and sloppiness again reads like an expression of your own guilt and insecurity.

      • So is the oxygen decline in the atmosphere. The carbon uptake by the ocean and land is another proof that they are not acting as long-term sources.

        I’m probably saying huge mistakes, but these aren’t compelling evidence that the source of CO2 is “man-made” at all (although I’m not really much skeptical about it, I do worry about rigor and integrity of logical arguments). These arguments are only evidence that CO2 is increasing.

        CO2 has fluctuated between ~180-280 ppm over the last million years and done so at considerably slow rates.

        This is the best counter argument so far, and I find it quite compelling. The dear doctor’s thesis is that these records aren’t too trustworthy, that the ice cores for instance have a natural process of “smoothing out” the isotopes, so that when they are read, you get to see a smoothed historical graph, and not “the real thing”.

        The feedback influence from temperature is on the order of 10 ppm per degree (if pressed, I will find a reference, there was a good one a couple years ago but I forgot the name)

        Stil do you agree this is a point still pretty much in research? I’d love to see those sources to check the method to which they arrived at that number.

        I am tired of people treating every new idea as if it is really a big deal, ONLY because it has something to say against “AGW.”

        They are far more fascinating than the boring ones. But that’s just human nature.

      • “…of the order of 10ppm per degree…”. Chris’s figure (for the change in atmospheric CO2 per degree change in temperature) is within the range calculated for ocean water temperatures in 1999 by J. Ahlbeck, who concluded:
        “…a temperature increase of one degree celsius will increase the atmospheric concentration of carbon dioxide in the range of 8 ppm (150 m layer) to 18 ppm (600 m layer). The influence of the assumed layer thickness is great in the beginning, but for thicker layers the influence will level out. If we assume that the whole ocean (mean depth 3795 m) is in equilibrium with the atmosphere, a one degree celsius global warming will increase the atmospheric carbon dioxide concentration by 28 ppm. For a very long time scale (ice ages and interglacials) the whole water volume may be in equilibrium with the atmosphere…”
        Ahlbeck, J. (1999) at

        Even at the high end of this range, it is difficult to attribute more than a tiny proportion of the recent increase in atmospheric CO2 to the rather limited amount of global – or oceanic – warming actually observed during the last century or so.

        I hope Prof Salby has taken this aspect into account in his forthcoming publications.

      • What is not accounted for in the calculation of 8-18 ppm / 1 C is the mixing rate of the ocean. The bottom of the oceans contain vast quantities of dissolved CO2 at about 4C. When this wells to the surface in the tropics it absorbs vast quantities of (missing) heat, increasing in temperature by about 20C while releasing CO2. How much CO2 is released is not known, because the mixing rate is not known. At the same time, CO2 is absorbed and sinks towards the poles, to reappear 800 years later at the equator.

      • Steve Fitzpatrick


        Yes, the argument has virtually no technical merit. Few who have examined the available data, and given it some thought, would argue otherwise.

        That is still no reason to be offensive. Being offensive serves no purpose.. unless you want to make sure people don’t like you. I wonder, do you imagine that makes your arguments more effective?

    • Chris

      I am not writing that humans are not putting CO2 into the atmosphere or that it does not contribute to warming.

      If you can not acknowledge that we do not know what percentage of total atmospheric total CO2 is due to humans, then you are not being truthful.

    • John Whitman

      Chris Colose,

      I apologize for interrupting, you being so busy with your crude baiting of our gracious host here at Climate Etc. May I have a moment with you? I am sure Judith wouldn’t mind my interruption.

      I empathize with you. It is probably difficult being in the back of the bus now when, prior to the events culminating in climategate, you were used to being up front of the consensus climate bus guiding the bus driver.

      For background on the bus analogy I reference my transcript of a portion of Professor Murray Salby’s talk on ‘Global Emission of Carbon Dioxide: The Contribution from Natural Sources’ given at the Sydney Institute on 2 Aug 2011,

      Salby said, “The popularized view has been that CO2 is driving the bus and climate is along for the ride. The observed behavior reveals just the reverse. Climate is at the wheel and, to a significant degree, CO2 is at the back of the bus.”

      Chris Colose, you are projecting yourself as highly erudite in the issues of CAGW. Therefore I implore you to teach us the benefits of your learning versus Salby’s. Please do as Prof Salby implores (my transcription) in his talk at the Sydney Institute:

      Salby said, [. . .]“There is no such thing [as “The” science]. Science is dynamic. Its predicated on discourse, questioning, that’s how we get to the truth. Were it not for discourse we’d still be in the dark ages. Excluding discourse from the equation isn’t science, its advocacy. [. . .]

      Look forward to your discourse specifically toward Professor Salby. I am sure we all can learn from it. Thanks.


      • John, thank you for your transcript of these statements.

      • John Whitman


        You are most welcome. I have more transcripts of the last 10 minutes of his talk where he summarizes and concludes. I will try to interject them into the dialog as it develops.

        Thanks for this very wonderful place. Being here causes me to imagine the intellectual salons of turn of the century Paris and Vienna. : )


      • Salby said, [. . .]Excluding discourse from the equation isn’t science, its advocacy. [. . .]

        When I’ve tried to ask questions about the contradictions in Climate Science over at RC I’ve always been censored. That seems to prove that the science is truly settled, as far as RC is concerned.

        The question I’ve asked is this: If climate science is settled, then why spend 1 penny more in researching climate? There can be no value in researching something that is already known.

        Wouldn’t it make much more sense to take this money (100 billion and counting) and use it to put people back to work, increase the tax roles, pay down the debt and make the economy more competitive?

        Why pay people to research settled science? Put them to work doing something productive. Something that generates value. Building infrastructure rather than red tape. There is plenty of red tape already.

    • Chris – My response to this post is somewhat similar to the one I gave regarding the Loehle/Scafetta paper. It is sometimes frustrating to see a post focusing on claims by a cited author that are almost certainly spurious, but the subsequent discussion can be useful in several regards. It can help identify flaws in the claims through appropriate reference to data. It can help us (or at least me) review the evidence in my own mind to ensure that I’ve interpreted it correctly. It can give us insight into the latest climate blogosphere fad that is circulating, before it has a chance to be replaced by a new one. And finally, it can expose uncertainties in our own minds that require us to await further details to be sure we are not overly confident in our conclusions.

      Like you, I don’t see anything cited in this post that is likely to change our understanding of the dominant role of anthropogenic CO2 emissions in mediating the rise since preindustrial days, but I’m willing to wait things out to see if something unusual turns up. As I said before, I wish words like “wow” and “revolutionize” had not been used, because they impart an importance to Salby’s claims that can’t be justified by anything so far presented here or elsewhere in the literature or in the blogosphere.

      Although not directly in response to your comment, I’ll add that evaluating the Salby claims emphasizes the need for us to make a distinction that is routinely neglected in attempts to distribute attribution between natural and anthropogenic contributions – timescale. Without doubt, changes in internal climate dynamics, particularly those such as ENSO that involve upper ocean heat redistribution, contribute to variation in atmospheric CO2 concentrations. What they cannot easily do, however, is perpetuate a trend in those concentrations, because they themselves go up and down over much shorter timescales than the long term trajectory from preindustial days to today. Over that long interval, we have more than enough evidence to implicate anthropogenic activities as almost the sole cause of the rise in atmospheric CO2. The ability of internal dynamics to modify concentrations on shorter timescales would not conflict with these conclusions even if the short term variations were greater in amplitude than they appear to be. The apparent conflict between natural and anthropogenic roles in climate change can often by resolved by relegating each to its appropriate timescale.

      • Fred,
        OT but a technical point regarding one of your favorites, OA.
        I suggest you read the essay attached:

      • And btw, speaking of Loehle/Scafetta, none other than Willis Eschenbach took L/S to task at WUWT for what he said was improper use of stats. So indeed, the discussion can be valuable even if the paper isn’t. I actually learned some useful techniques from that thread.

        Of course, it also shows that Willis is more interested in getting to the bottom of things than scoring points for his team. A little more of that on both sides of this issue would help a lot.

      • I completely agree…although the comments on this thread are lively

    • Chris, that’s actually a very bitchy comment of yours. What the hell do you want? Judith found this talk to be interesting and wanted a discussion about it. She made it clear she has very little understanding about this particular subject, not that she would “reserve judgement” about it.

      So people take it as they want. You imply that this argument has no validity whatsoever. That’s great Chris, could you enlighten us why? These discussions could be so cool if people actually engaged them rather than diss them.

      • Luis,

        See my response above to hunter. Also, I am glad people want to discuss things, even things that are “well known” like how the greenhouse effect works. It encourages understanding, and we all (including myself) pick up interesting insight.

        But I am tired of all of these types of threads devolving into how everything is uncertain, everything is important, and every new claim needs to be thought through thoroughly and “rebutted.” Good discussion can be generated without the need to post obvious nonsense in order to get people thinking. Perhaps the idea that good discussion can only be encouraged by the back and forths of every new “AGW is wrong!” paper is testimony to the lack of climate knowledge or interest out there.

        The fact is that we know the CO2 increase is due to humans. We know gravity is real. We know evolution happens, and I’m tired of people insulting the ones who actually study and work on the technical nuances of these topics under the Galileo-dressed “science is about questioning!” Some work is just junk, such as Loehle and Scafetta’s curve fitting game. Judith Curry has the knowledge to spot these issues, and despite the “if” contained in “If Salby’s analysis holds up, this could revolutionize AGW science,” she knows her quotes will get spread around and looked at closely. She has the training to actually comment on the topic as well, even if she is not a carbon cycle expert.

        That is how I feel. Of course, you are free to disagree and JC is free to run her blog as she sees fit.

      • Well Chris you can’t save the internet. This is the place where millions of people come to discuss things, to tell the neighbour netizen “how wrong he is” (or worse, how stupid he is), and of course you’ll always have newcomers, prejudiced people, stupid people, intelligent people, you name it.

        And so of course these kinds of “posts” will always appear time and time again. And they are excellent for people to learn stuff if there are good conditions for those discussions, namely that the moderation isn’t biased (at least that the people don’t feel it is biased), and that there is a varied range of perspectives from the commentators.

        The second one is the hardest to achieve, I think, because sites or blogs do tend to be balkanized (in that regard, I avoid commenting on both WUWT and on RC, since I would be pretty much marginalized and bullied in both of them right on the spot). It’s not even people’s fault, this is a universal phenomena in the internet.

      • For the record, I wish I had Fred’s patience here. I am sure I am just constantly frustrated at the internet, and the things people believe about science.

      • I just now seen one of Gavin’s post, highlighting the same point I made above to hunter about the sensitivity of CO2 rise to temperature. He found a reference though…

        [Response: Yes. Having now listened to the podcast, I thnk he has done a regression of growth rate to temperature (and soil moisture) over the recent period. The sensitivity he then derives is projected back using the 0.8 deg C warming over the 20th C. However, this is ludicrous – the sensitivity in the recent period can’t be more than say, 1 ppmv per 0.1 deg C. Projected back you would have say a 10 ppmv (max) change over the 20th C. Paleo-climate constraints demonstrate that CC feedback even on really long time scales is not more than 100 ppmv/6 deg C (i.e. 16 ppmv/deg C), and over shorter time periods (i.e. Frank et al, 2010) it is more like 10 ppmv/deg C. Salby’s sensitivity appears to be 10 times too large. Someone might want to have a look at the data and redo the regressions, but the physics is screwy. – gavin]

      • Chris

        You conclude- “the sensitivity in the recent period can’t be more than say, 1 ppmv per 0.1 deg C.”

        How exactly did you make this determination?

      • It’s gavin doing the calculation, not Chris Colose, but it seems pretty obvious how.

        If we have, say, a drop of CO2 in the ice ages from 280 ppmv to 180 ppmv, and the temperature drop is 6C, then the derived sensitivity of CO2 to temperature change would be 100ppmv/6C, or 16ppmv/deg C.

        That would be over a long period of time. Over shorter periods, the transient response would probably be more like 10ppmv/deg C. (see his Frank et al reference).

        That would be 1ppmv/0.1 deg C.

        Lots of nuance left out there, but it’s plain that Salby is well off.

        Also, anyone care to address dikranmarsupial’s point about mass balance? Since we’re emitting MORE than the CO2 that is ending up in the atmosphere, clearly the oceans and land must be acting as a net sink. So how can they be acting as the source?

        It’s not just the isotopic signature, or the decline of atmospheric oxygen concentrations – which is the signature of the source of the CO2 being combustion… It’s also this simple mass balance argument.

        I’m going to predict that credulously rushing to promote this is going to be a real embarrassment to Dr. Curry. Even if on publication we discover that Salby is making a more subtle point than something that “could revolutionize AGW science”, hyping it now as such will have been an embarrassment.

      • Gavin’s argument makes the fallacy that all temperature change is externally forced. If the temperature change is caused by natural internal variability, then this argument is not useful.

      • Gavin’s argument makes the fallacy that all temperature change is externally forced. If the temperature change is caused by natural internal variability, then this argument is not useful.

        Huh? Unless I’m completely misunderstanding something, the claim that Gavin is rebutting is that the observed CO2 flux is primarily caused by temperature change. It doesn’t matter whether that temperature change is caused by the Sun, fossil fuels, internal variability, or invading Martians. A warming planet will produce a positive CO2 flux; a cooling one will produce a negative flux. How does the CO2 flux know whether a given temperature change is externally forced or a result of “natural internal variability”?

      • Of for pete’s sake, Gavin is only saying that the paleo record during just the past few ice age cycles seems to constrain the “sensitivity of CO2 to temperature” to far less than what Salby seems to be implying.

        What is fallacious about that? And note well: Salby is talking about the sensitivity of CO2 to temperature. It’s how he is attempting to explain the CO2 rise, not the temperature rise, which he appears to accept.

      • Gavin’s is the fallacy that CO2 is the driver of climate, not albedo, not land use changes, not changes in hydrologic flows, not solar variability.
        That would be a large fallacy.

      • Hunter writes: Gavin’s is the fallacy that CO2 is the driver of climate, not albedo, not land use changes, not changes in hydrologic flows, not solar variability.

        That has nothing to do with the issue here. Salby says that the flux of CO2 into and out of the atmosphere is primarily determined by the earth’s temperature. Gavin (correctly) points out that if a relatively small temperature change of the past century caused the observed 115 ppm change in CO2 concentration, then much larger changes in past global temperature (e.g., glacial/interglacial temperature changes) ought to have caused swings in CO2 of 500-1000 ppm. Obviously, that didn’t happen.

        Gavin’s point seems quite reasonable. Dr Curry suggested there’s a fallacy in Gavin’s argument, one somehow related to the difference between internal vs external temperature forcing. It would be interesting to learn how the CO2 flux knows whether a given global temperature change is due to the “right” kind of temperature forcing.

      • Judith Curry,

        Gavin’s argument does not rely on the attribution to temperature change at all. There is absolutely no evidence that CO2 can rise close to modern values (from preindustrial) as a response to < 1 C rise in temperature in less than a century. None. Zilch. The "uncertainty" card will not win the hand here; there are more than enough paleoclimate events in the past that would pick up on a CO2 feedback sensitivity this high. It does not matter if internal variability, anthropogenic, or magic dust fairies caused the warming. We know the land and oceans are acting as a sink; we have isotopes; we have O2/N2 ratio dropping…Please see


      • JC writes: “Gavin’s argument makes the fallacy that all temperature change is externally forced. If the temperature change is caused by natural internal variability, then this argument is not useful.”

        Please justify this claim. I have no idea what you’re basing it on.

      • Now this is a very good argument by Gavin. I’ll be waiting for a response on that.

      • TimTheToolMan

        Although we haven’t seen the graphs themselves, I believe Salby’s argument was based on analysis surrounding know and well measured events such as Mt Pinatubo and La Nina.

        Perhaps we need to question the accuracy of proxy reconstructions to get historical temperatures. There’s a lot of scope there for complete wrongness.

      • These carbon sequestration calcs are only based on the temperature sensitivity of the solubility of CO2 in water. The total turnover of CO2, on an annual basis has been estimated in the range of 200Gt., +- 40%. aCO2 is estimated at about 6-7 Gt lately. What are the mechanisms involved in absorbing and desorbing these quantities of CO2? They can’t simply be solubility. So chemical reactions must be involved- formation of carbonates and other carbon containing compounds, biomass reactions, etc. All of these reactions are also temperature dependent both in absorbing and desorbing CO2. ; From thermodynamics, chemical reaction rates approximately double for a change of 10 degK. So, a 1 deg. C change in temperature would cause a 2-3% change in reaction rate. Applied to 100 Gt, that puts all the increase in CO2 since 1800 in the observed range. With uncertainties of 40% or more it is hard to be more accurate.

        Nothing requires that all these reactions occur simultaneously or at the same rates. Sequestration in the deep ocean could be very slow, but has a long time to work. There is plenty of room for cycles, similar to the PDO or AMO but chemical in nature, to absorb and release CO2 over long periods. Given the many uncertainties involved it seems pretty cavalier to assume that the earth’s carbon cycle has been determined and that the increase in CO2 is unequivocally caused by human emissions.

      • philc, a key chemical mechanism is equilibrium between CO2 in the atmosphere and dissolved in the oceans. This doubles about every 25 degrees C, leading to the 10 ppm per 1 deg C number. It is Henry’s Law that plays a big part over the oceans, at least. I don’t know of situations where this law can be violated on long time scales. It should be quite a tight constraint and it comes from chemistry.

      • J,
        CO2 as the primary driver of climate is the issue. The AGW promoters have claimed for years that CO2 has very long residence times in atmosphere. That is now being questioned, as well as if temperatures lead CO2, as the record seems to indicate, or if CO2 drives it, as AGW claims.
        Understanding how CO2 actually operates is fundamental to the question.
        If the understanding of isotopes is incorrect in the consensus, then that is significant.

      • I don’t think Gavin has grasped the issue correctly, at least he has not addressed the isotope issue at all.

      • Someone might want to have a look at the data and redo the regressions, but the physics is screwy.

        Only if you assume the data is accurate and all other things are unchanged. Even a small change in the deep ocean upwelling will lead to large quantities of dissolved CO2 being heated 20C+, or large quantities of CO2 being removed from the atmosphere at the poles.

        Modern instruments have a different bandpass than do ice cores. You can’t compare them reliably to determine if one is unusual as compared to the other, unless the sample interval is sufficiently long. We do not have sufficient length of data in the modern records. This is better covered in signal processing theory.

      • Mr. Schmidt needs to check his Internal Hubris Alarm — it seems it must be broken, it should have been sounding loudly after he wrote ‘but the physics is screwy’.

        It would be a point of professional courtesy to assume that Dr. Salby, an acknowledged professional whose specialty is Atmospheric Physics, has not made some goofy ‘grad student claims to have discovered the theory-of-everything’-type mistake. After all, he wrote a/the textbook on Atmospheric Physics and while it is possible that there can be a disagreement about the physics involved, calling his carefully considered result ‘screwy’ physics is certainly out-of-line. It might be better for Dr. Schmidt to admit that he simply does not yet understand the points Dr. Salby made in his short, rather preliminary, presentation, quite possibly because of the lack of visuals and the general nature of the talk–or, if he did understand, but disagrees, to state that. But this type of bad manners never serves well.

        I am simply a long-term observer of the scientific sideshow known as the Climate Wars. I have seen several comments here and elsewhere asking ( in many different ways) ‘Why would Salby sit on his results for a year, then send them for comment to trusted friends, waiting another six months, if his results are so important?’ I have just this morning googled ‘Murray Salby’. The answer is obvious from what one finds with this simple exercise. He might as well have announced sighting the Planet Nibiru heading for Earth. Over 800,000 google hits and rising fast. I envision he knew he was risking his career and professional reputation. I’m sure, once his paper has been published, that he will explain something along the lines of spending a year checking and re-checking his assumptions and calculations, looking for where he may have made a misstep. Satisfied, he sends his results to respected friends, on the QT, saying in effect, before ‘before I put my career on the line, before I throw my hat in the Climate Wars ring, would you side-check my work?’ Apparently, their answers encouraged him. His paper reportedly has passed peer-review and is scheduled to be published. We are to understand that some data are under embargo. A fascinating story — I look forward to the paper when it comes out, and the effect it will have on the Climate Wars saga. I just love the way real science works.

      • Kip Hansen writes: It would be a point of professional courtesy to assume that Dr. Salby, an acknowledged professional whose specialty is Atmospheric Physics, has not made some goofy ‘grad student claims to have discovered the theory-of-everything’-type mistake. After all, he wrote a/the textbook on Atmospheric Physics and while it is possible that there can be a disagreement about the physics involved, calling his carefully considered result ‘screwy’ physics is certainly out-of-line.

        This “dispute” or whatever you want to call it isn’t really about atmospheric physics. It’s about the carbon cycle. Has he ever done any research at all on anything related to the carbon cycle? I’ve read his list of publications and there’s nothing even remotely related to it.

      • J –
        Not sure where you’re coming from but your point has no validity. Salby is an atmospheric physicist. Just what do you think an atmospheric physicist does? What kind of education do you think an atmospheric physicist might have? AND – why do you think the carbon cycle is not part of that education and experience?

        I worked with atmospheric physicists for the best part of 40 years and, frankly, you’re making an ass of yourself. Those on your side of the dance floor may buy into your smear job – if they’re ignorant and/or stupid. But don’t expect ALL of us to do so.

        Notice – I did NOT say he’s got it all right – that remains to be seen. But the mob scene to discredit him by any means possible is a good indication of the fear level among your compatriots. And a good indication that he may just be onto something.

      • John Whitman


        Your views are a testament to the scientifically independent orientation. It can be a testament because of the existence of this open blog site (and others like CA/BH/WUWT/etc, etc, etc) where we can hear such words as yours.

        Thank you sincerely.


      • We KNOW that the amount of CO2 in the oceans has increased. How? Because the pH has decreased (that is measured) because of increased CO2 in the atmosphere and the decrease in pH matches what is expected from the increase in CO2 in the atmosphere.

        Anyone trying to claim that the increase in CO2 in the atmosphere is due to warming of the oceans has to get through that one.

      • John Whitman


        “”” We KNOW . . . ”””

        Is that the Royal we?


      • Why yes, glad you noticed. See the Royal Society report on ocean acidification

      • Chris

        You say YOU KNOW the increase is due to humans.

        We know that humans are emitting lots of CO2, we also know that natural variability of CO2 can be equal to human emissions and vary over time.

        How do you KNOW what percentage of the change is due to
        humans vs. due to the changes in natual emissions?

        What measurement method do you say we can use in Aug. 2011 to determine what percentage of total atmospheric CO2 is human caused? Can we walk through the math?

      • Let us put it very simply, with made up numbers. In one year, nature emits 6 tons of CO2 and humans emit 2 tons of CO2. The total increase of CO2 in the atmosphere for that year is 1 ton. This means that 7 tons of CO2 was absorbed by carbon sinks. So all 6 tons of the naturally produced CO2 was absorbed by carbon sinks and 1 ton of the human produced CO2 was absorbed by those same carbon sinks, and we thus know that the increase of 1 ton of CO2 is due to human emissions.

        Is that simple enough for you all? If the increase in CO2 is less than total emissions by humans, then the increase is all accounted for by human emissions.

      • Holly- Unfortunately the real world is NOT your example. In the real world we know that natural CO2 emissions vary over time. We also know that humans are emitting CO2 but can only estimate how much. We have no reliable means to determine what percentage of atmospheric CO2 is human caused at any specific point in time.

        Given what I have written above to be true(and it is) how do we know more than rough estimates??? We dont

      • You are making an argument from ignorance. You don’t know these things so you assume that no one else does; but scientists do things like figuring out how much CO2 is being emitted.

        You want to know how they do it? Read the real reports by real scientists, including their footnotes and the things they link to. But that would be hard work, wouldn’t it?

      • As Salby stated human emission of carbon is well documented due to its expense.

      • Holly,
        You would be closer to the mark if you said, “In one year, nature emits 100 tons of CO2 and humans emit 2 tons of CO2. The total increase of CO2 in the atmosphere for that year is 1 ton. This means that 101 tons of CO2 was absorbed by carbon sinks”

        Of course, you’d then have to explain just how total natural sources managed to track total sinks within 1 ton/year, for many thousands of years.

        And if you have to invoke a negative feedback mechanism to explain that apparent stability, then you’d have to further explain why that negative feedback mechanism hasn’t swallowed up the recent anthropogenic component.

      • Cgp Chris price

        Easy, c4 co2 absorption mechanism is an energetic vacuum.
        Ppmv is nothing but a residual indication of the performance of this vacuum mechanism. Nature offers a sink that can rapidy follow any wayward source spikes.

      • That is a simple but incomplete to the point of being an inaccurate response

    • With a PhD and a couple or three US$ bucks, or Europa Euros, you can get a cup of coffee at a few places.

      Throwing your bona fides from The Academy onto the table gets you negative points in many environments. Zero is usually the highest point value attainable.

      It’s what you know and how to apply that knowledge in a manner that advances the technical issues at hand that gets positive points in productive environments.

  38. Blockquotes failed in the above comment. Here’s the quote:

    Fossil fuel burning approx 6.4 Gt per year
    Atmospheric flux from natural sources is approximately 200 Gt of which:
    about 90 Gt is ocean
    about 110 Gt is biomass
    Uncertainty on sources/sinks in nature +/- 30 to 40 Gt

    • Not only uncertainty. Even small variations in natural sources (3-5%, which are a given, it can not be 100% constant) are like is 6-10 Gt/year.

      • You both forget one thing: against natural sources stand natural sinks, We only have rough estimates of the height of the sources and sinks and of their year by year variability, but we have quite exact figures of the difference between natural sources and sinks and their variability: that is the difference between the human emissions and what is measured as increase in the atmosphere.

        That shows that in the past 50 years the natural sinks were (near) always larger than the natural sources. See:
        The current emissions are around 8 GtC (4 ppmv) per year, the current sink rate about 2 ppmv and the (temperature caused) variability in sink rate is +/-1 ppmv around the trend. Thus human emissions are about 200% of the increase in the atmosphere, about 200% of the sink rate and about 200% of the variability in sink rate.

        No matter if human emissions are 3% or 0.3% or 0.03% of the natural sources, the former are additional, while the latter only circulate in and out, without any contribution tot the total mass of CO2. That is turnover not addition,

      • The system is the atmosphere and does not include oceans and land. We measure CO2 concentration in the atmosphere. The addition is inputs minus outputs.

      • We measure net changes in the oceans by monitoring pH.

  39. Thanks Judith for bringing to our attention Murry Salby’s critically important presentation. I understand Murry Salby to say that net CO2 variations are the difference between large natural sources and sinks dominated by temperature and soil moisture, with anthropogenic emissions forming a small contribution. He clearly explains and adds recent satellite data to similar materials from other researchers. Look forward to his graphs & paper.

    Geologist Tom V. Segalstad at emphasizes similar issues regarding large natural CO2 flows as highlighted by Murry Salby. See Carbon cycle modelling and the residence time of natural and anthropogenic atmospheric CO2: on the construction of the “Greenhouse Effect Global Warming” dogma.

    Both radioactive and stable carbon isotopes show that the real atmospheric CO2 residence time (lifetime) is only about 5 years, and that the amount of fossil-fuel CO2 in the atmosphere is maximum 4%. Any CO2 level rise beyond this can only come from a much larger, but natural, carbon reservoir with much higher 13-C/12-C isotope ratio than that of the fossil fuel pool, namely from the ocean, and/or the lithosphere, and/or the Earth’s interior.
    The apparent annual atmospheric CO2 level increase, postulated to be anthropogenic, would constitute only some 0.2% of the total annual amount of CO2 exchanged naturally between the atmosphere and the ocean plus other natural sources and sinks. It is more probable that such a small ripple in the annual natural flow of CO2 would be caused by natural fluctuations of geophysical processes.

    Jo Nova posts Blockbuster: Plantary temperature controls CO2 levels — not humans .
    She links to figure: Tom Quirk: Sources and Sinks of CO2
    She links to Roy Spencer’s posts along similar lines: “Could the Ocean, Rather Than Mankind, Be the Reason?” See Fig. Mona Loa dCO2/dT (Fraction of emission “showing up” in atmosphere)
    Also: Spencer Part2: More CO2 Peculiarities – The C13/C12 Isotope Ratio

    The flea climbing the elephant trunk has been getting very agitated over the “hockey stick” rate of climb apparently associated with the rate of temperature increase on his travels. I wonder what he will think when the elephant takes a drink and then decides to trumpet?

    • David,

      I had a discussion with Segalstad on a sceptic conference in Brussels,.He speaks about the fast residence time of CO2, But that only says how much CO2 is going in and out of the atmosphere over the seasons (about 20%) but that doesn’t influence the total amount of CO2 after a full cycle, if ins and outs are equal, Only how much is added or removed over a year is important, not how much circulates, And that is far less (about 4 GtC/year) than what is circulating…

      And as already said by others: dCO2/dT says nothing about the cause of the trend, because you have effectively removed the trend by taking the derivative…

      • Ferdinand
        Thanks for the graph. However, I understood Selby to examine the natural sources and sinks and rate of change of CO2 and show that they were much larger then anthropogenic emissions. Furthermore, the CO2 variations did not correlate with anthropogenic emissions, but with temperature and soil moisture. I look forward to his presentation and publications.
        Have you read Spencer’s discussions etc?

      • David,

        Indeed I have had discussions with Dr. Spencer on the same topic. The error both Spencer and Selby make is to look at the rate of change, which is influenced by short term temperature changes (and precipitation) with a ratio of about 4 ppmv/degr.C (based on the 1992 Pinatubo cooling and the 1998 El Nino warming. But most of the temperature changes level out over time. Any consistent warming has an influence of about 8 ppmv/degr.C over very long term (ice ages, interglacials, MWP-LIA). By far not enough to explain the 100+ ppmv increase. The current trend has an extremely good correlation with the emissions:
        but far less with temperature:
        where temperature changes of halve the scale have little influence on CO2 levels.

      • Thanks Ferdinand
        From Selby’s talk, he mentioned CO2 dependent not just on temperature but also on soil moisture. The latter can vary with clouds and thus with the 21 year Hale cycle modulating cosmic ray variations, and also with cosmic rays themselves as we traverse galactic spirals. e.g. see WJR Alexanders work which shows precipitation, runoff and floods correlating with the 21 year Hale cycle, but NOT evaporation. Similarly, see Henrik Svensmark on cosmoclimatology. Selby also noted major variations with el Nino and volcanoes.
        Thus temperature variations driving CO2 is expected (necessary), but not the total picture. i.e. cAGW still “Not Proven” by Scotts legal code. Rather, there is growing evidence per Selby of much larger natural fluctuations.

        Happy hunting

      • Ferdinand Engelbeen
        See Fred H Haynie The Future of Climate Change
        He provides fascinating detailed analyses of CO2 variations showing the CO2 sub components varying with the respective polar ice. Note particularly the dramatically different shapes for CO2 pulses between Arctic, Tropic (Mauna Loa) and Antarctic (slide 10), as well as the isotope depletion (Slide 11.) I find Haynie’s detailed analysis of natural drivers more believable explanation than the overall anthropogenic emissions fit. Please find periods where there are major swings in the various parameters and then test for how well they fit.

      • David,

        I have read Fred’s work already some time ago. The problem with his approach is that it relies too much on curve fitting/comparison, but with little or no process evaluation.

        Based on the ice coverage – CO2 level match, he thinks that the main change in seasonal CO2 levels is from ocean sinks. But if you look at the 13C/12C record, it is clear that growing vegetation in spring (and rotting in fall) in the NH is the main cause. The same for the % of human influence on the d13C ratio, etc…

  40. Dr. Curry,
    It is impressive that you are willing to permit fellwo scientists who challenge the climatocracy be heard. Thank you.
    It is amazing to see the reactionary responses of the AGW community.

  41. Love this topic, but am very busy today.

    Here is a pair of figures from a steady state model of atmospheric CO2.
    The first is a plot of anthropogenic carbon vs. Keelings [CO2].

    This shows that the pre-Industrial [CO2] was in the order of 280-300 ppm. It also shows that there is a step in the relationship, probably caused by either temperature, anthropogenic changes to the biotic capacity or more likely that the efflux of CO2 from the atmosphere is of an order greater than 1 (i.e. has a first-order and second-order reactions).

    I tried to do a fit to explain the pre-Industrial [CO2] = 295 ppm, 590 GT total atmospheric carbon, and the increases seen by Keeling, 380 ppm, 763 GT total. Using this fit I get t1/2 CO2 efflux of 29 years.
    I can get quite reasonable fits using t1/2’s of between 7-35 years, with slightly different intercepts for the pre-industrial levels.
    One cannot get a fit using longer t1/2’s.
    The actual t1/2 is near a decade;

    A point to remember. Think of CO2/C in the biosphere as body heat. You lose body heat all the time and use themogenic reactions to maintain it in a reasonable range.
    As well as heat being circulated, it is lost to the body and regenerated.

    Every mineralized carbon atom, coal, oil, methane, insoluble carbonate is lost to the biosphere. What is also lost is the carbon that falls to the bottom of the oceans, the raining ‘shit’ fog that covers wrecks like the Titanic/Bismark, is destined to form sedimentary rocks with a high carbon content. This is an efflux from the system, is the most part gone. Gone for good, except in geological time. Carbon is lost to the biosphere all the time.

    The primary inputs into the system are from CO2/CH4 released from anearobic microorganisms, vents and vulcanos, introducing pre-fossil, fossil and primordial carbon back into the biosphere.
    You may note that all of the Carbon cycle diagrams, like this one:-

    all miss, or play down, the mineralization efflux and volcanic influx of Carbon out of and into the biosphere. I guesstimate that the natural efflux/influx , mineralization/vulcanism, vents and CO2/CH4 rock leakage, rate is about 22 GT y-1.
    The oceans act as a carbon buffer, but plants will drag CO2 out of the atmosphere until they are CO2 limited, which brings us to about 280 ppm. At these levels, carbon fixing is hugely inefficient, with at least a third of all the redox potential being lost on mis-fires. Over geological timescales, the biosystem will drag CO2 down to 280-300 ppm. A rapid input of CO2, either from burning fossil fuels or from a big volcanic event will cause a short term rise in atmospheric CO2, followed by a rapid sequestration.

    One need only fit Keeling’s CO2 to the known release of anthropogenic CO2. Fit Keeling’s CO2 line-shape to known anthropogenic CO2 and you can work out the efflux.

  42. An excellent discussion of how bomb-generated 14C is used to constrain carbon cycle components, and related issues, can be found here.

    A relevant excerpt:
    “It has been erroneously argued that the observed atmospheric CO2 increase since the middle of the 19th century may be due to an ongoing natural perturbation of gross fluxes between the atmosphere, biosphere, and oceans. That the increase is in fact a predominantly anthropogenic disturbance, caused by accelerated release of CO2 from burning of fossil fuels, has been elegantly demonstrated through 14C analyses of tree rings from the last two centuries…[references follow]”.

  43. Recent comments here and in other threads raise questions about the choices Judith Curry makes in citing claims of a “contrarian” nature as the starting point for some discussions. If this were my blog, my choices might be different, but she has reasons for her choices that I’m prepared to accept.
    I have some thoughts about those reasons that I’ll mention here. I assume she may be reading what we write, and so she can correct me when I misrepresent her.

    I believe Dr. Curry is very angry at the IPCC leadership because she believes they betrayed her and other scientists who took the IPCC conclusions on faith, repeated them, and then found out that some in the leadership had been cooking the books. That made her and others feel foolish, and she appropriately resented it. She still accepts many basic climate science principles but no longer believes that the most important IPCC conclusions should remain unchallenged. She routinely issues those challenges in the form of the topics she posts, and the implicit challenge that all of us should make our judgments without blind acceptance of the pronouncements from authority or their implied certainty, just as she is prepared to do based on her own expertise.

    I came to read the IPCC reports fairly late in the course of my own climate science learning curve. If I had never read them, I would have come to conclusions that were 95 percent similar to the conclusions in AR4 WG1 (with less confidence in WG2 and 3). I believe the strong role of anthropogenic contributions to climate change with potentially significant adverse impacts (global warming and ocean acidification) is well documented by a large array of independent evidence. Regrettable behavior on the part of some prominent IPCC figures would not change that. That the IPCC and climate science (and scientists) are very distinct entities deserves constant emphasis and reemphasis. It is never acceptable in my view to promote the view that we can judge one from the other.

    But she is saying, “Well, if you believe that, can you effectively refute THIS CHALLENGE, and THIS ONE, and THIS NEXT ONE? Which is why we see many of the posts that appear here.

    Well, can we?

    Almost certainly yes – not in the minds of anyone with unalterable opinions, but in the perception of readers who come here looking for answers rather than arguments. It is those readers who are our audience, and to whom, in my mind, we have an obligation to be well informed, truthful, and as objective as possible.

    I hope to continue trying to do this. I will refer to the IPCC from time to time as a source of information, but not authority. There is more than enough evidence available without IPCC reports to address all the challenges that arise here.

    Every one of these topics deserves more space than we can give it. Anyone expecting me to use this comment to document my conclusions about the entirety of anthropogenic climate change will be disappointed, but I have addressed individual points on many past occasions and will continue to do so in the future. I expect that will lead me often to agree with Dr. Curry, but at times to disagree with her on certain points – less about basic principles than on measures of uncertainty that she sees as more impactful than I do – but that’s a good reason to keep these exchanges going, and on a professional and courteous basis. It’s also a good opportunity to learn while helping others to learn as well.

    • Well said, Fred. I always read your comments and even if I don’t always agree with them, I always find them intellectually challenging and informative. I just wish some of the visiting scientists would adopt your unvarying politeness.

    • Fred,

      That’s a thoughtful response. I would be more sympathetic to that narrative if it actually had the productive qualities that Judith probably does at the end of the day intend. However, I’ve seen no evidence of such. If you have, that’s wonderful and I’d love to know about it.

      The threads I’ve read at length seem to be largely “skeptic” echo chambering and backslapping, with admirable contributions of sanity by you, Pekka, and a few others. The “technical ‘skeptics'” that Judith so relentlessly pursued for an audience fall largely in with the former, and only rarely in with you in the latter.

      While it may be true that Judith intended this blog to be a place where climate science was strengthened in trials by fire, its impact so far has been to bury the field under garbage (I believe that Judith has a T-shirt with a related theme). I see this blog cited approvingly by “skeptics” online, and it has without exception been in the context of dismissing, ridiculing, or otherwise attacking the mainstream. Whenever I myself have tried to cite it or Judith’s writing at say Climate Audit in a reinforcing or supporting role (to say nothing of her actual publications), these efforts are dismissed. No matter how hard Judith tries to earn her “skeptic” bona fides and proclaim herself an outsider, when she has the temerity to acknowledge the reality of anthropogenic warming and the threat it poses, she’s written off behind her back as a “warmer”.

      She may believe she’s building bridges between “skeptics” and the mainstream, but so far these bridges have been decidedly one way.

      • It may seem like an echo chamber, but that is just because your ears are ringing from the believer echo chambers you have dwelt in most of the time.
        I would suggest that the first fallacy to deal with is CO2 = ghg=AGW.
        The AGW is generally defined to mean “any impact”.
        That is a meaningless definition.
        Yet when skeptics point this out and and suggest that ‘dangerous impact’ be used instead, we are treated rather poorly.
        When we point out that on things like OA for instance, the reality is that the idea fails when actually measured, we get endless repeats (echo echo echo) of the same misleading work regarding ocean pH.
        If climate science is science it is strengthened when it is challenged. Because the bad ideas are tossed out and replaced with better ones. Not because those who believe in the bad ideas win.
        Yet the latter has been the case in cliamte science for far too long.
        Your attribution of motive regarding what is allegedly said behind Dr. Curry’s back is just an example of fallacious assertion.

    • Sorry but the behavior of some climate scientist is questionable not just the IPCC and you forget how often those scientists are at the heart of the IPCC reports , indeed their often the lead authors. There is no simple split between the two.

    • Fred writes “Well, can we? ”

      The question I would ask you, Fred, is this. Is the science settled with respect to CAGW? That is, has CAGW been proved, scientifically, beyond any doubt? Or do we skeptics/deniers have a case that CAGW is very far from proven? What I find diffficult to get my mind around, is that people like yourself are convinced that CAGW is a problem, yet, as Girma points out, there is almost no observed data to support this contention . Such observed data as we have seems to show that CAGW is NOT a problem.

      • You don’t need to prove a threat beyond doubt. A credible threat is enough without requiring specific disaster to be beyond doubt.

        Observed data certainly doesn’t show that CAGW is not a problem. You can only conclude a change is safe if a) it’s happened before without consequence or b) you understand fully what will happen. Neither is the case.

        CO2 levels are going to more than double in a mere couple of centuries. There is no known example of that ever happening in the past. Such an unprecedented perturbation to the carbon cycle is a serious threat given that the carbon cycle is a key part of the environment.

      • lolwot –
        You don’t need to prove a threat beyond doubt. A credible threat is enough without requiring specific disaster to be beyond doubt.

        You do if you’re demanding that the ec0nomies of all the nations on the planet be rearranged to accomodate your undefined and undefinable fears.

        You can only conclude a change is safe

        That’s a foolish statement. “Safe” is a meaningless word. It implies that nothing bad will ever happen. And that notion is insupportable in any context.

        CO2 levels are going to more than double in a mere couple of centuries.

        That’s another “assumption”. You seem to operate on a LOT of unwarranted assumptions – and not very muchin the way of solid information.

      • “You do if you’re demanding that the ec0nomies of all the nations on the planet be rearranged to accomodate your undefined and undefinable fears.”

        Uh what? I am talking about CAGW, not an economic rearrangement. If you can’t even stick on topic then I won’t bother pointing out your other errors.

      • lolwot –
        Uh what? I am talking about CAGW, not an economic rearrangement.

        Just what do you think is the purpose of CAGW? What do you think Kyoto – and Copenhagen – and Cancun were about? Are you really that obtuse? C’mon, man – I thought better of you than that.

      • Lolwot@Aug5 7.36pm:
        [ Dr Curry, I’m sorry—I know this isn’t technical, but I hope you’ll allow me to reply to Lolwot’s assertions.]
        Lolwot—-your comment is disingenuous beyond belief.
        ‘Economic rearrangement’, as you call it, is absolutely a live issue.
        Here in Australia, our government has announced that a carbon tax, with carbon priced at $23 per tonne, will be implemented eleven months from now.
        This government [ Labor] describes the tax and the ETS to follow, as the greatest transformation of the economy in Australia’s history.
        But Australia’s economy is probably one of the most carbon-intensive in the world, considering almost all of our electricity is coal-fired, and coal is our biggest export earner.
        No one in the government or the AGW scientists who have their ear, and have a Climate Science Commission and a running campaign going to re-educate us, will even address any questions raised on the science, or questions on which renewables will provide the base load power that coal now provides, and what products will replace the massive loss in export income we will suffer.
        Our AGW scientists [ the only scientists given any respect in Australia] respond to questions on the science or the scientific process by shutting down any pesky questioners with ‘the science is over’—‘the science is settled’—‘the science was settled decades ago’—as do most AGW climate scientists.
        I only mention this, because you and some other warmists pretend that if only we just do the right thing and ‘believe’ in AGW, everything will be all right—- when the truth is that a country like ours stands to lose its prosperity, our children’s futures and our standard of living for the foreseeable future—- all on the strength of the scientific conclusions that your AGW scientists have so little confidence in, that they’re afraid to have them scrutinised and questioned by other scientists.

      • a country like ours stands to lose its prosperity, our children’s futures and our standard of living for the foreseeable future

        That’s hilarious. I presume you are arguing that excessive taxation is going to destroy your children’s future — there’s not something magical about taxing carbon as opposed to taxing property, or income, or restaurant-going.

        So how heavily is Australia tax burden, and how much will a carbon tax add?

        Taxes as a percentage of the GDP (all figure from wikipedia): 27.1%

        Top ten countries from the WEF competitiveness rankings:

        Switzerland — 30.3%
        Swenden — 46.4%
        Singapore — 14.2%
        United States — 24%
        Germany — 37%
        Japan — 28.1%
        Finland — 43.1%
        Netherlands — 39.1%
        Denmark — 48.2%
        Hong Kong — 13%

        Even including the two city-states, one of which is part of China, 7 of the 10 ten economies in the world have a heavier tax burden than you. The only large state-state on the list with a lower tax burden is the US — you can ask Standard & Poor if we’re a good example to emulate.

        The Australia plan is accompanied by offsetting tax cuts, but we’ll ignore those for the moment. The expected revenue from the tax is $4.2 billion in the first year. That’s about 0.3% of the GDP, taking Australia to the dizzying height of — 27.4%. Still less than seven out of ten of the world’s top economies.

        Meanwhile your unemployment rate is 4.9%, and your public debt is 22.4% of the GDP. I think you’ll be OK.

      • Robert –
        I think you’ll be OK.

        That’s arrogance/hubris.

        Unless you live there, you haven’t a clue about conditions “on the ground” and all you’re doing is regurgitating numbers.

        I suspect that nobody cares what you think.

      • Robert:
        Good to see you’re amused, but are you sure you know what you’re talking about?
        Do you honestly believe the only tax impact that matters is the total tax burden—regardless of the type of tax, type of economy—the energy available etc?
        At present, 93% of our electricity is coal-fired, and other than gas temporarily, all we can resort to after coal is killed off is renewables. We have almost no hydro, and Labor rules out nuclear for the foreseeable future.
        So maybe you can tell me which renewables are ready , or will be ready in the foreseeable future, to provide base load power for industry—certainly not wind, solar or geothermal.
        We do have low unemployment, but that’s the result of the very well-run economy left to the previous Labor government by the conservative government before them in 2007 —the economic conditions that allowed us to ride out the GFC with little damage.
        It’s also a factor of our labour-intensive mining industry —the industry that will take a huge hit on its competitiveness from the carbon tax.
        We have a two-speed economy, and the mainstream economy is suffering a crisis of confidence due to this carbon tax, among other things.
        Coal is our biggest export earner, and the carbon tax and ETS to follow, are the start of the slippery slope for that as well.
        Most of our big export earners are carbon-intensive, and many are likely to go offshore to competitor countries, with no carbon tax and less efficient industries.
        We will probably have to import cement from China, where its production produces nearly twice as much in CO2 emissions, as its production in Australia does— a net rise in global emissions—not a fall.
        China will probably get its coal from countries that are more price competitive, but have lower quality and dirtier coal—more CO2 emissions—not less.
        In fact we’ll have to import almost everything we now manufacture , because we’ll be unable to compete with our high wages v the low wages in Asia, and a carbon tax on top of that.
        There’ll be an increase in global emissions —not a decrease.
        I know you couldn’t care less about all this, but whatever country you look at, prosperity is needed to fund the huge technological challenges ahead—and the US and Canada will find they have similar problems.
        If the science is settled, and this is the fundamental issue of our times, then why are AGW scientists so desperate to shut down debate on core aspects of it?
        Why are warmists already so angry about Professor Murry Salby’s paper, without even seeing it?

      • What dangers from the past have been demonstrated from CO2 increasing?
        As to your prophecy for the future ppm of CO2: bunk. You have no way to know what CO2 ppm will be in 100, much less 200, years.
        More importantly, you have no idea of what he impact of that increase will be on those people.
        Finally, you have no right to impose costs on us today for your guesses about 200 years out.

      • “What dangers from the past have been demonstrated from CO2 increasing?”

        When has CO2 ever increased this fast in the past? That’s the point. Coupled with CO2 affecting climate. This isn’t some irrelevant little change that’s being made to the carbon cycle.

        “As to your prophecy for the future ppm of CO2: bunk. You have no way to know what CO2 ppm will be in 100, much less 200, years.”

        I can easily see where CO2 is heading at it’s current rate and how much fossil fuels exist for humans to burn through. A doubling will be easy as pie, we are already about 30% of the way there.

        “Finally, you have no right to impose costs on us today for your guesses about 200 years out.”

        Where did I talk about costs? I am pointing out the threat from CAGW is well established. If you don’t want to do anything about that threat, fine, but don’t deny it exists.

      • “Finally, you have no right to impose costs on us today for your guesses about 200 years out.”

        Read Stephen Gardiner “Climate Change, the Perfect Moral Storm” on this.

        This means not only that one generation is not motivated to accept the collectively rational outcome, but also that the problem becomes iterated. Since subsequent generations have no reason to comply if their predecessors do not, noncompliance by the first generation has a domino effect that undermines the collective project. . .

        The upshot of all this is that in the case of climate change, the intergenerational analysis will be less optimistic about solutions than the tragedy of the commons analysis. For it implies that current populations may not be motivated to establish a fully adequate global regime, since, given the temporal dispersion of effects – and especially backloading and deferral – such a regime is probably not in their interests. This is a large moral problem, especially since in my view the intergenerational problem dominates the tragedy of the commons aspect in climate change.

        Second, insufficient action may make some generations suffer unnecessarily. Suppose that, at this point in time, climate change seriously affects the prospects of generations A, B and C. Suppose, then, that if generation A refuses to act, the effect will continue for longer, harming generations D and E. This may make generation Aʼs inaction worse in a significant respect. In addition to failing to aid generations B and C (and probably also increasing the magnitude of harm inflicted on them), generation A now harms generations D and E, who otherwise would be spared. . . .

        Third, generation Aʼs inaction may create situations where tragic choices must be made. One way in which a generation may act badly is if it puts in place a set of future circumstances that make it morally required for its successors (and perhaps even itself) to make other generations suffer either unnecessarily, or at least more than would otherwise be the case.

        . . . climate change is not a static phenomenon. In failing to act appropriately, the current generation does not simply pass an existing problem along to future people, rather it adds to it, making the problem worse. For one thing, it increases the costs of coping with climate change: failing to act now increases the magnitude of future climate change and so its effects. For another, it increases mitigation costs: failing to act now makes it more difficult to change because it allows additional investment in fossil fuel based infrastructure in developed and especially less developed countries. Hence, inaction raises transition costs, making future change harder than change now. Finally, and perhaps most importantly, the current generation does not add to the problem in a linear way. Rather, it rapidly accelerates the problem, since global emissions are increasing at a substantial rate such that generation D would be kept below some crucial climate threshold, but delay would mean that they would pass that threshold.

        If passing the threshold imposes severe costs on generation D, then their situation may be so dire that they are forced to take action that will harm generation F – such as emitting even more greenhouse gases – that they would otherwise not need to consider. What I have in mind if this. Under some circumstances actions that harm innocent others may be morally permissible on grounds of self-defence, and such circumstances may arise in the climate change case. Hence, the claim is that, if there is a self-defence exception on the prohibition on harming innocent others, one way in which generation A might behave badly is by creating a situation such that generation D is forced to call on the self-defence exception and so inflict extra suffering on generation F. Moreover, like the basic PIP, this problem can become iterated: perhaps generation F must call on the self-defence exception too, and so inflict harm on generation H, and so on.

      • Rabbit,

        Let me summarise my response to you. The problem you mentioned has not existed.

        Don’t waste your life on a non-existing problem and do some real sicentific work such as why N2 radiation in the Earth’s atmosphere does not have to obey radiation laws.

      • Quadrupole emission/absorption + collisional induced dipolism. Still about as vanishingly weak as the rest of your nonsense

        For those interested a href=”,or.r_gc.r_pw.&fp=5d738012b56afd96″>i the details

      • I am new here and somehow got this from Eli Rabbit. I don’t know what he is trying to say. Collision-induce dipole emission/absorption is indeed weak and broad banded. Nonetheless it is real. I don’t have a clue what it contributes to the radiation balance, but simple collision energy transfer from CO2 to ?N2/O2 is enough to spread and trap heat in the atmosphere and allow LTE modeling of radiation.

      • Jay, It doesn’t contribute anything significant. See Comment by Sam NC @ 10:09 August 7

      • Jay,

        N2, H2, and such gases can become good greenhouse gases in high density (and preferably lower temperature) regimes, and are on gas planets, or Titan (Saturn’s moon). They are not on Earth. Sam refuses to accept that but he is simply wrong. He continues to reference vague “radiation laws” but all of this is described in basic radiation literature and textbooks.

      • Rabbit & Chris,

        You denied N2 energy content is nonsense. You guys are real deniers of real energy in favor of unreal CO2 super overblown radiation heat flux.

      • N2 energy content is given almost exactly by equipartition at atmospheric temperatures, e.g. 5/2 RT per mole where T is the local temperature and R the gas constant in whatsoever damned units you want. Eli’s favorite is ft-lb/(oz-mol Rankine).

        The point is that it cannot get rid of this energy by IR or Visible radiation. Your statement about N2 radiation in the Earth[s atmosphere not having to obey radiation laws is irrelevant and a fine example of how knowing the question to ask means that you have 80% of the answerhas a lemma that some questions such as yours have no meaning because they are based on a set of false assumption.

        The odd types of radiative emission that are allowed simply are too weak to have any effect other than a couple of nice papers by folk like Walt Lafferty..

        Keep this up please. It’s amusing.

      • Eli Rabett:
        Is it your contention then, that coal and oil should never have been used as energy sources —or that we should have stopped using them in the 1950s ?

        If so, do you believe the developed countries would have been as innovative ?
        And what energy source would have powered all of the industry and technological advances since then—and who would have decided what was acceptable and what wasn’t, and how would global compliance have been achieved?

        Do you think that with that nobbling of development , there would have been the incentives to innovate?

        If you think you know now, what’s best for future generations far removed from now, why do you think the thinkers of the fifties or earlier didn’t likewise design our lives for us in what you think would have been a better way?

        How can you be so certain that future generations would not say we panicked on very little information , ignored the many unknowns and allowed ourselves to be diverted from real and pressing problems of poverty, much of it caused by lack of energy—to chase a phantom problem that could be resolved as technological progress followed the wider prosperity achieved as poor countries developed?

      • “Finally, you have no right to impose costs on us today for your guesses about 200 years out.”

        With “hours” in place of “years” this is pretty much the argument of the captain of the Titanic, who was under enormous pressure to reach New York on time.

    • Fred,
      The IPCC is made up of those ‘other sources’ you claim are so much better.
      What happens to those sources when the IPCC uses them?

  44. What I don’t understand is this: if I dump 1 gallon of water into a pool and the water level increases by 1 gallon, it’s hard to argue they aren’t connected, even if other hoses are going into the pool. Thus, since we dump 10 GtC into the atmosphere, and the amount increases by a fraction of that amount, how can it be that we’re not responsible? Is there an explanation of why CO2 would have increased by that much even if humans were not dumping CO2?

    • I am by no means writing that humans have not raised atmospheric CO2 levels. I am saying we do not know, but make assumptions as to how much humans have impacted total atmospheric CO2.

      To simplify the idea– if 95% of atmospheric CO2 is natural but we do not know how much overall the natural emissions amounts change over time, but we do know they change, it is easy to see that a 10% change in natural emissions would have potentially great change to total CO2.

      For someone to state that WITHOUT A DOUBT I AM SURE 100% (or almost 100%) of the rise in emissions is due to humans seems unsupportable.
      To all the posters who believe we KNOW all the increase in CO2 is due to humans- I say we do not even KNOW how much CO2 humans are emitting. We have at best rough estimates of human emissions.

      Using another example- imagine you have a pond with several streams filling it with water. You have noticed that several of these streams seem to fill the pond at different rates over the year. Let’s say you then turn on your hose and add it to fill the pond. After a while if you notice the pond has filled do you know it was due to the hose solely, or did the streams feeding the pond change what they were adding, or did the rate of evaporation/loss change? It might have been your hose, and it clearly had an impact, but can we say with certainty how much?

      • “To all the posters who believe we KNOW all the increase in CO2 is due to humans- I say we do not even KNOW how much CO2 humans are emitting. We have at best rough estimates of human emissions.”

        To the contrary, we have accurate fuel records showing that the CO2 from the burnt fuel has been very close to twice the increase in atmospheric CO2 over more than the past two centuries. Unless you have evidence contradicting this data, you are just pulling random statements out of thin air.

    • I dunno, racerx.

      Maybe a lot of the commenters on this blog have difficulty with the concept of conservation of mass? Or with basic arithmetic?

      I don’t actually believe that. I think if you posed this question in abstract terms, most of the commenters here would be able to get the answer quite right:

      C = A + B
      A > C

      Is B positive or negative?

      Obviously, in this formulation, A is the anthropogenic flux (well known), B is the natural flux (not easy to measure directly), and C is the net change in mass of atmospheric CO2 (well known).

      But because some people are deeply emotionally invested in rejecting anything related to “anthropogenic global warming”, they struggle to grasp what would be obvious in any other context (like your swimming pool, or a bank account).

      Anthropogenic emissions of CO2 represent > 100% of the observed annual increase in atmospheric CO2. If someone can’t acknowledge that fact, it’s a good sign that you probably shouldn’t take them seriously.

      • This offering from Dr. Curry should help put to rest the idea that most of her readers (except the Sky Dragons! of course, we’re not like “them”!) accept the basic principles of anthropogenic climate change, and are just focussing on uncertainties like climate sensitivity and the like.

        With the least provocation, many will quickly glom onto an argument that “could revolutionize AGW science”: that we aren’t even the principal cause of the atmospheric CO2 increase.

        As to not getting something as simple as that algebra, one need only look as far as this pretzel logic to see the contortionist efforts that are made to convince oneself that somehow B > 0. Dreadful.

        And all of this without even seeing Salby’s actual work…

      • Not nearly as telling as those beleivers dismissing the work before it is published, or slandering the author without ever hearing from him prior to today.

      • You are probably right. Some of us are just dumb aerospace engineers. We probably do not understand math. LOL

      • We probably do not understand math.

        Rob, I’m quite sure you understand how to multiply and exponentiate numbers you obtain from a random number generator.

        I seriously doubt however that you have a clue how to obtain numbers having any bearing on future climate.

      • Your premise;

        C = A + B, C = B + A, C – A = B?, C – B = A?

        It’s a fallacy. You already know that B is undefined (you said so) but certainly B > A is likely.

        C – B = A

        B > C could make “A” a negative number, this doesn’t follow since we know that it is a positive input. It gets worse;

        Why does it fail? Because “B” is an elephant and “A” is a peanut at the zoo. “A” can be completely eaten at the zoo and “B” could still drive “C” higher.

        The real fallacy that matters is that “B” isn’t treating “A” like a peanut which in fact it is in your equation. “C” is going up or down regardless of what “A” is doing. The fact that co2 fluctuates while “A” is a relative constant proves the point;

        AGW co2 compounding is a failed idea. How could C – A = B If you claim to know both C and A by measurement while not knowing what B is???? It’s really because A isn’t that important to C but you will never accept this because of your bias. If you stand with C – A = B that is a joke but so is agw compounding.
        There are better arguments to make, using rate of change numbers given the scale of B is the first issue. The real failure is thinking on a daily operating basis B can’t swallow A in a relative heartbeat and either way C really doesn’t change much because of A. It’s an essential fraud argument to AGW.

        Finally, why would co2 fluctuate at all if “A” was like magic compounding? Where does it go when it’s declining?;

        Does “B” have some sort of bowel movement process where it gives back “A” once it swallows it and pushes in rocks, plants and soil?? Is that the claim? Face it, most of the co2 even a few months ago is done gone! This is all co2 accounting Sophistry and nonsense because if NOAA for one, listed all the co2 inputs on a single chart with all the sink functions few of the AGW minions would get excited. That’s why it’s framed this way and the idea that a percentage of current C is all or even a good chunk of past A isn’t based on any observational evidence. It’s totally counter to how the carbon cycle works.
        A needed fiction for a cause, nothing more.

        Any other snark about who is serious and who isn’t?

      • Doug Badgero

        Very little of the carbon in the carbon cycle is contained in the atmosphere and therefore it cannot contribute to GH warming even if the rest of the consensus argument is valid. If the pulse time constant assumed is wrong (too long) then most of the anthropogenic carbon released will be sequestered in the soil, water, etc. Arguments about conservation of mass are meaningless unless we can better constrain the natural flux(es).

      • Very little of the carbon in the carbon cycle is contained in the atmosphere and therefore it cannot contribute to GH warming even if the rest of the consensus argument is valid.

        Very little of the arsenic in the ground is in this beverage, and therefore drinking it cannot impair your health.

        One of the challenges faced by climate scientists is keeping a straight face when confronted by the stupidity of skeptic logic.

      • Now, you’ve changed your variables. But, the argument is still dumber than toast. See my post at August 6, 2011 at 3:24 am.

      • But, the argument is still dumber than toast.

        Your toaster teach you that line?

      • J

        these are nets. The increase in conc has no bearing on the total value
        of a minor input.
        There is no relationship. It might be that the extra minor input is directly
        sinked with a time lag of five years by those C4 scarity eaters.

        What is it that stops your thought process here?
        Ah I know. A common mistake that Salby is attempting to
        bust and that is ‘constant background processes’. That would
        foul up your thinking. Like the constant never changing by even a tiny
        amount – the sun, background cosmic rays, and tada …

        global circulation sea and land temperature and soil moisture,
        all constant so we can blame the nasty industrialists.

    • Go google Le Chatelier’s Principle.

    • Near as I can tell the argument is an analogy to a buffered acid/base solution. So imagine you’re pouring some small amount of hydrochloric acid in a buffered solution. You won’t change the pH at all, really. Now suppose you lower the concentration of the buffer. That will result in a higher pH.

      The idea is we’re doing both these things at the same time, and that folks are looking only at the pH of the system and the fact that we’re adding HCl and saying “the ppm of hydronium ions is increasing, we’re adding hydronium ions to the system, therefore we’re responsible for the increase.” The author’s retort would be “the buffer change controls everything.”

  45. The Japanese have a GHG observing satellite up, they launched it about the same time as the failed nasa one.

    Ill have to wait till there is something substantive to read on this before im likely to change my beliefs in the origin of the co2 rise. Ive been convinced that fossil fuels are largely responsible…. but

    I certainly have my doubts about some of the CH4 accounting ive read(with cattle) it seems we only look at one side o the equation, whats emitted. But last time i checked ch4 had an atmospheric life of 7years, before it breaks down to co2 and h2o, but the C origin is ignored(last time i checked, cows eat plants, plants photosynthesis) So with a change in the total mass o cattle on the planet being able to possibly cause a perturbation, it should be neutral after 7 years. Its not stopping taxing going ahead, this does cause me some pause.

    • It’s not quite so simple for various reasons having to do with the chemistry and the circulation in the atmosphere, Also the 7 years is not the time that all the methane breaks down, but the half life, so half is left after ~7 years, 1/4 after 14, etc.

      • Thanks for that Eli, but i would like to get to the bottom of this, its a Q thats irked me for some time, and the few papers ive come across on it, dont adequetly to my mind acount for the origin of the C.

        We input N, P, K & S. And the N can be from fossil fuel sources, but thats for protein, and aids in photosynthesis, but the C would be atmospheric in origin? And with the seven year half life, established herds should not be a contributor to a rise in CH4(most herds would be 50 plus years old, new herds could contribute, but there contribution should have deducted the natural breakdown of organic matter’s CH4)

        I doubt you will read this, i will persue it with the local agricultural science organization here… but a link addressing this would be appreciated.

        maybe a weee bit off topic ;-)

      • King, Eli doesn’t think so because among other things, herds have been growing at enormous rates. FAO should have the data, although it might be easier to look in the international statistics part of the US Statistical Atlas at

  46. RacerX and few others have nailed it. Discussions of isotope ratios and uptake and emission of CO2 by all the various and sundry physical and biological processes are distractions to the simplest and most compelling line of evidence that the increase in atmospheric CO2 concentrations is primarily anthropogenic – to wit, comparing the expected concentration increase based on anthropogenic emission rates with the actual increase over a given period of time.

    Based on production and usage data for various fossil fuels, we can reasonably (though not perfectly) estimate the mass of anthropogenic CO2 emitted to the atmosphere in a 1, 5 or 10 year period. We can also, with reasonable accuracy, estimated the total mass of the atmosphere. It is then nothing but simple math to estimate how much the anthropogenic emissions should have increased the anthropogenic concentration. From what I understand, the actual concentration increase is always less than what would be expected from the mass of emissions. No need to get sidetracked by isotope ratios, natural sinks and sources, paleoclimatic conditions, etc. – Heck, you don’t even have to worry about what the actual pre-industrial average was since we are only looking at the change over a given period of time.

    Admitting that we are emitting Gt’s of CO2 into the atmosphere and thus affecting the atmospheric concentration of CO2 doesn’t mean that you also have to agree with the IPCC on the climate sensitivity to CO2, that CO2 is the primary cause of warming in the late 20th century, or that warming of a few degrees C will result in really bad things happening. It just means you are admitting that when you add a chemical to a solution, you expect the concentration of the chemical in solution to change.

    • Not that simple. I agree that the isotopes don’t mean anything, but your model has no sinks, and we know that isn’t true by simple mass balance. If what you’re saying were true, CO2 would be rising twice as fast.

      • That’s my point and RacerX’s point. Based on the mass of anthropogenic CO2, emissions in a five year period, we can calculate the expected increase in atmospheric concentrations. Since the expected increease is greater than the actual increase, the increase is primarily due to anthropogenic sources and the oceans and biosphere are acting as sinks.

        Sure there are probably fairly substantial error bars on the estimates of annual anthropogenic emissions (+/- 15-20%, maybe) but that doesn’t prevent one from making the calculations. Also there is no doubt that processes primarily control the flux from various natural sources and sinks and we have a lot to learn in that area.

      • Bob- when you write “primarily” or even put a qualifier like “probably or most likely” I would agree. It is when people claim “100% for certain” that their claims appear unsupportable

      • BobN – This is horribly fallacious reasoning. i can’t believe so many people who believe themselves smarter than the average bear are falling for it. See my comments interspersed above.

    • BobN,
      Were those isotopes meaningless when they were used to shut down lines of inquiry regarding the origin of the CO2 inthe atmosphere?
      Or were they only meaningless when they impled a vastly shorter t1/2 for CO2 in the atmosphere than the climatocracy needs? O are they only worhtless now that it might be that CO2 effluxing from oceans as they warm a bit could account for a substantial amount of CO2?
      Scientists would welcome this being clarified.
      Which tells a lot about those climate scientists who are dismissing this from the start.

    • Have ANY of you comprehended Salby’s argument?
      Please tell us his mistake.

      Is his point about the natural variation of
      0 to double annual co2 increase misguided?

      Comment on how the new satellite data is irrelevant.

      Please leave other off topic issues and get to the point of the paper.
      This is no place to for counter arguments not related to the correlation
      of the annual c02 increment (NOT) to steady human emissions.

  47. You said :

    curryja | August 4, 2011 at 1:04 pm | Reply
    I am working to esp delete posts that violate blog rules

    Yet you allowed this?

    Oliver K. Manuel | August 4, 2011 at 7:17 am | Reply
    Thank you, thank you, Professor Curry, for another moment of truth.
    Propaganda artists have manipulated and used good citizens of the once “Free West” by the same bag of “political correct” consensus opinions that once openly controlled the other half of the globe.
    With kind regards,
    Oliver K. Manuel

    Judith don’t pretend that you’re some conscientious observer, a conscientious or thorough one would wonder why there are so many issues with what he had to say. Even little lies like “Satellites have complete global coverage” wrong… and “Prior to the satellite era only 35% of the earth has coverage for instrumental records” wrong… Please tell me why is this such an important podcast?

    • Just for clarification, that’s a different Robert.

      I agree with some of his sentiments. I would not agree that Dr. Curry is “pretend[ing]” to be a “conscientious observer” although like many of us, she is probably more affected by her own biases and cognitive dissonance than she is aware of.

      I do doubt this thesis’s impact on AGW, but I can hardly point fingers as to the practice of calling attention to new ideas or observations and saying “It’s early days, but what if?” Blogs are a good place for that sort of speculation.

      When it comes to this comment, I agree it fails the test of relevance:

      “Propaganda artists have manipulated and used good citizens of the once “Free West” by the same bag of “political correct” consensus opinions that once openly controlled the other half of the globe.”

      But there is a much bigger problem with it. Dr. Curry has often written of her concern for the credibility of mainstream scientists, and or the positive impact “skeptics” can have on the discussion. If you believe those propositions, then presumably “skeptics” also have to be concerned about their credibility — if they lose credibility, they will not be able to make any positive contribution.

      In the wake of Brievik’s mass murder of 74 people at a summer camp, preceded by the release of a manifesto denouncing climate change as an “eco-Marxist conspiracy,” the association of climate “skeptics” with the far right has become incredibly toxic to any credibility “skeptics” might hope to wield outside the closed systems of Beck and Limbaugh. Taking a hard line on comments pontificating on right-wing nonsense unrelated to climate change would be an excellent start in trying to create a corner of the climate “skeptic” universe that might one day be clearly disassociated from those “skeptics” that write letters to climate scientists telling them to gargle razor blades.

      • Taking a hard line on comments pontificating on right-wing nonsense unrelated to climate change would be an excellent start in trying to create a corner of the climate “skeptic” universe that might one day be clearly disassociated from those “skeptics” that write letters to climate scientists telling them to gargle razor blades.

        Thank you.

        I have been trying for months to make that point to Judith, although admittedly, with far less eloquence.

        Perhaps she’ll be able to hear it from you.

      • Robert,
        You return to your vile slander about the Norwegian killer like a dog to his vomit.
        You explain tous the similarities between the unabomber’s writing, gore’s writing and the eviro movement.
        You explain Pol Pot’s desire to ‘pastoralize’ Cambodia and the enviro desire to deindustrialize society.
        You explain to us hansen’s endorsement of “Time’sUp!”, the call to global destruction of technological infrastructure.
        And finally explain to us why a certain early 20th century charismatic politician and his deeply seated green credentials are not at the heart of the enviro movement.
        Your disgusting fact-free slimeball attack in trying to associate a demented lone actor spouting words to justify his mass murder to skeptics is only matched by your shameless ignorance of the roots of the enviro movement.

      • What does that have to do with the posted topic?

      • Only that true believers can wander off track in ways indistinguishable from the severely mentally disturbed.

      • OK, get back on track

  48. The science has not changed, i.e., temperature drives atmospheric concentrations of CO2.

    What the proponents of AGW have argued is that man over the past 60 years has turned that science on its head, i.e, increasing man-made CO2 emissions drive temperature.

    All Murry Salby has done is to show that arguement is nonsense, the science has not changed – temperature continues to drive CO2.

    You cannot blame humanity for rising global temperatures, nor can humanity control levels of atmospheric CO2.

  49. Michael Larkin

    I’ve just read Jo Nova’s piece about this, and I think it’s very good indeed – at least for a layman like me. I’m not saying anything about the value of Salby’s piece – others more qualified than I will make that judgement. But it makes sense of what I had difficulties grasping from the podcast: at least I know now what Salby is saying.

    • I’ve just read Jo Nova’s piece about this, and I think it’s very good indeed – at least for a layman like me.

      Michael, Jo Nova’s piece completely misses the point. The temperature/CO2 feedback accounts for much of the year-to-year variation in the rate of the atmospheric CO2 increase, but it doesn’t account for the increase itself.

      Basically, humans burn fossil fuels, resulting in a flux of CO2 to the atmosphere. Some of that excess CO2 is soaked up by the ocean and biosphere, while the rest of it accumulates in the atmosphere. Over the course of the ENSO cycle, the ocean and the biosphere are able to take up a little more, or a little less, of that anthropogenic CO2 than they do in an “average” year. But the ever-increasing mass of CO2 in the atmosphere is obviously due to human emissions.

      • Michael Larkin

        I don’t think it misses the point of Salby’s lecture. If you think it is missing a point that you happen to believe, well, that’s your prerogative, but it isn’t relevant to my comment.

    • The Nova piece is terribly wrong. It might fairly represent what Salby is saying, but if so it makes him terribly wrong too.

      This is some McLean ENSO nonsense all over again but this time with CO2.

      When you realize how solid the science is that CO2 rise is human caused, you can read articles like that Nova one and spot all the little propaganda tricks. The careful omissions, the wordplay. Fascinating, but not in a good way.

      • lolwot,
        The attribution of motive to skeptics, when it is the cliamte scientists who were caught in cliamtegate, is a bit hypocritical on your part. You can say many things about Jo Nova- and obviously do- but I would suggest taht implying she is a liar, as you do, is really a demonstration of either bigotry on your part or ignorance of what she is actually saying.
        What is fascinating is when certain climate scientists and their supporters defend lying, palying with data, ratinolizing secrecy with data, distorting the null hypothesis, etc.

  50. Just to follow up on my last post, here’s my question:
    1. we know that atmospheric carbon is increasing (over the past few years) by about 5 GtC/yr
    2. we know that humans are adding about 10 GtC/yr
    3. thus, non-human sources must be subtracting about 5 GtC/yr

    this would confirm that humans are the cause of the increase.

    what am I missing?

    • Your argument is basically valid, and in my view the strongest reason to believe that the increase is mostly, if not totally, due to human activities. The logic is, however, not fully solid, as there is another alternative. This alternative is very unlikely in my judgment, but still an alternative. It requires two factors:

      1. There must by another additional source of CO2 on top of the carbon fluxes that have maintained the balance.

      2. There must be sinks that can absorb both half of the human contribution and all of this additional source. This means that the natural processes that act to return the CO2 level back to its “normal” level must be very strong, not only strong enough to absorb half of the deviation, but much more than that.

      I haven’t seen any serious proposals on, how these two requirements would both be satisfied. On the contrary, there are many publications that tell that the natural processes could balance approximately that part of the human contribution that doesn’t stay in the atmosphere. At the same time it’s clear that the carbon cycle is not known accurately, but there are uncertainties that add up to an significant part of the annual increase of the CO2 concentration.

      • Pekka if I may, 1. Salby noted in his podcast that the earth has been warming since the little Ice Age and continues to do so today. Warmth leads to increased CO2, so there is your additional source. 2. While he declined to elaborate in that podcast, though he indicated that he would do so at some point, he posited that the was a source of negative feed back when of necessity would lead to a dampening of the effect. He, as do many others, see this as a necessity or else the whole process would roar out of control at the least provocation. So yes he to see the alternative has at least the qualities that you do. Only he finds it not unlikely, but necessary.

      • Warming leads to increased CO2 release from the ocean, but the effect is far too weak. The total solubility of CO2 (total dissolved inorganic carbon) in sea water has been studied, and the equilibrium CO2 concentration of the atmosphere rises very little, when the water temperature rises by one degree. This alone cannot explain more than few percents of the increase. The weakness of this effect is the explanation also for the fact that the process does not roar out of control. In the main stream thinking this is a small part of the positive feedback.

      • How about other changes to the oceans? We’re sitting at about half the pre-industrial fish and plankton populations. Could that alter the equilibrium?

      • Pekka if I may, 1. Salby noted in his podcast that the earth has been warming since the little Ice Age and continues to do so today. Warmth leads to increased CO2, so there is your additional source. 2. While he declined to elaborate in that podcast, he posited that the was a source of negative feed back which of necessity would lead to a dampening of the effect. He, as do many others, see this as a necessity or else the whole process would roar out of control at the least provocation. So yes he too see the same alternative which has at the least the two qualities that you do. Only he finds it not unlikely, but necessary.

    • Actually the flux can be anywhere from 3.5 to 7GtC/yr over the last 10 years … supposedly.

      Using an average when the swing is so huge is dodging the import questions that Salby is trying answer … what actual causes such massive swings.

      • The important question has an answer: The swings are in the sinks. In warmer El Nino years the ocean sink reduces resulting in a larger atmospheric CO2 rise and in colder La Nina or pinatubo-style years the sink is larger resulting in a smaller atmospheric CO2 rise. And I bet there’s a similar effect on vegetation. The longterm trends for these things fall under carbon cycle feedbacks and they are far from ignored.

      • So the earth has warmed up as much as an El Nino or so, therefore that causes more Co2 in the long run, just like an El Nino causes more CO2 in the short run.

        Sounds right. Temperature leads, CO2 follows.

      • yes the more we warm the earth up, that may reduce the CO2 sinks resulting in higher CO2 and even more warming

      • Or warming just causes more Co2. As it did in the Eemian.

      • CO2 was lower during the Eemian.

      • But it too rose 100ppm without human interventian after temperature rose.

        And that brings up another interesting point. Why was CO2 in the Eemian so close to extinguishing plant life? Why did CO2 in the Holocene start out higher?

      • But it too rose 100ppm without human interventian after temperature rose.

        It rose from the trough of the previous glacial to the peak of the interglacial. That corresponds to a temperature change about ten times larger than the 0.8 C we’ve seen in the past century. If CO2 flux is dependent on temperature, why would temperature changes that differ by a factor of 10 produce the same CO2 increase?

      • J, one thing to remember is that the LIA was deleted from Mann’s Hockey Stick as well as the MWP. Recent evidence from Greenland suggest a 4C drop to the depths of the LIA. That means a possible 4-5C rise the depths of the LIA.

        And since there is a lag …

      • The Eemian never got more than 3C above our current temperature.

      • But as the temperature during the Eemian was higher than today, one should expect CO2 levels to be lower than during the Eemian, but they are near 100 ppmv higher…

      • Ferdinand,

        We don’t know that. I disagree that CO2 levels were 100 ppm lower during the Eemian. Professor Salby disagrees too.

      • Ferdinand, CO2 did not go up before the MWP.

        And why did the Holocene start 100ppm higher than the Eemian?

      • Each summer has more co2 than the previous winter. Co2 is not driving the seasons. Co2 is a reaction to heat an vegetation.

    • Doug Badgero

      You are missing the fact that the natural fluxes are not nearly well enough constrained to make this leap……….and are by default assuming they are constant, or at least their net differences are constant at zero. We know that atmospheric CO2 is rising by about 5GtC/year. This means that the total of all fluxes is 5. There is an infinite number of solutions that can add up to a net 5 into the atmosphere.

    • What you are missing is the ~190 GtC/yr that cycles through the oceans and land mass, with an uncertainty of about 40 GtC. The mechanisms of that cycling are largely unknown and unstudied. We don’t even have enough data to analyze whether or not there might be oscillations in that cycle. Given all the known cycles in the climate(PDO, AMO, ENSO, etc) forgive me if I think that a 1-2% change in the global carbon cycle over a period of 50-100 years is probably more than likely.

      • “The mechanisms of that cycling are largely unknown and unstudied.”

        By you, certainly. But not by scientists. “Carbon cycle” pulls up 138,000 results on Google Scholar. “Carbon sink” — 21,100. “Soil respiration” — 32,600 articles.

    • You are missing that you do now know how much overall non-human sources are adding and subtracting separately. Because the net sinks expand with accumulated volume (nobody can deny that), you can simply have the subtraction tracking the adding, and human contributions could be no more than bit players.

      • Bart you’re on a mass balance mission.

        I hope it will get the “settled” scientists re-search the problem.

        I speculate we won’t have to wait too long for significant atmospheric CO2 decceleration evidence.

    • An assumption of constant background processes.
      The big arrows as Salby says MAY PERHAPS vary
      in their net outputs.

      There is a well known process control theory that says
      something like (it’s being 25 years since I graduated B.E. chem Eng)
      a 3 per cent input has no impact, the signal is washed out by other
      much larger varibles.

      By the way a 1 in 100,000 molecule trace on a trace of man made
      contribution having an effect (whatever the amplification sign)
      on the atmosphere would imply a grossly unstable system, one that
      would have venus’ed out billions of years past.

  51. John Whitman

    Even with the challenge on having no actual slides, original source transcripts and video I have taken a stab at a tentative takeaway from Prof Salby’s talk.

    My understanding from Salby is the GCMs used in AR4 and since have not included in their framework the main sources of atmospheric CO2 and their changes on the timescales of satellite and Mona Loa. Observations are used to support that critique. He evaluates CO2 changes backward before satellite and Mona Loa in support of the critique of the AR4 GSMs. To me it looks like the GCMs are misleading and continued high emphasis on them by the IPCC with its so-called consensus science is even detrimental to more open scientific discourse.

    In support of my understanding I have transcribed below Salby’s description the IPCC climate modeling framework (GSMs) at the ~28:56 min mark of the podcast of his talk ‘Global Emission of Carbon Dioxide: The Contribution from Natural Sources’ given at the Sydney Institute on 2 Aug 2011.

    “ (John Whitman personal transcription)
    Salby said, “Climate projections rely on an ability to predict CO2. It’s the one thing believed to be known because of the presumption we control it. Mainly, future atmospheric CO2 is determined entirely by human emissions. That’s what is specified in climate models, which then predict how climate will respond in so-called climate scenarios. The observed behavior reveals that, much as we might like it, the real world doesn’t work that way. Net emission includes a substantial contribution from natural sources. If you don’t control CO2 you can’t predict it, and if you can’t predict CO2 you can hardly predict how climate will respond.

    The climate modeling framework just described is the cornerstone of the IPCC. [. . .] I used to be a reviewer. Much of the public debate stems from the IPCC’s last report. The behavior you’ve seen [in my talk] was not known at the time of the report. Were it [known], the IPCC could not have drawn the sweeping conclusions that it did. Here’s why. As you’ve seen emission from natural sources is integral to observed changes of CO2. Its contribution hasn’t been recognized, nor is it represented in climate models. Because it involves emissions other than human, that is not solely human, future atmospheric CO2 is only marginally predictable and in significant part not controllable. That means the changes of human emission will not be tracked by changes of atmospheric CO2. They never have been.”


    • Salby is wrong. Future atmospheric CO2 is not determined entirely on human emissions. If it was there would be no discussion about carbon cycle feedbacks in the IPCC reports.

      I can’t see anything that Salby mentions that isn’t already known and factored in.

    • “As you’ve seen emission from natural sources is integral to observed changes of CO2. Its contribution hasn’t been recognized, nor is it represented in climate models. ”

      This quote is one of many that demonstrates that Salby does _not_ understand the state of the art on carbon-cycle models (or even the state of the art several decades ago). And apparently has not read chapter 7 of the IPCC (or needs serious reading comprehension lessons). For example, see Interannual Changes in the Carbon Cycle: “Since the TAR, many studies have confirmed that the variability of CO2 fluxes is mostly due to land fluxes, and that tropical lands contribute strongly to this signal (Figure 7.9).” One of the supports for this assessment? “(3) ocean model simulations (e.g., Le Quéré et al., 2003; McKinley et al., 2004a) and (4) terrestrial carbon cycle and coupled model simulations (e.g., C. Jones et al., 2001; McGuire et al., 2001; Peylin et al., 2005; Zeng et al., 2005).” How can you read that and claim that emissions from natural sources, and their contribution to interannual variability, have not been recognized or included in models?

      (oh, and the whole 13C thing has been known for a long time: “(2) consistent relationships between δ13C and CO2 (Rayner et al.,
      1999),” – or, google “13c global carbon cycle model”)

      Much like the SkyDragons debate, it makes it really hard to have a conversation about real uncertainties in climate science if we’re stuck arguing about whether the greenhouse effect contradicts the 2nd law of thermodynamics or whether the last century’s rise in CO2 concentrations is mainly due to natural causes. These are issues that were resolved half a century ago. Saying “If Salby’s analysis holds up, this could revolutionize AGW science” is like saying “wow, if the analysis on that Moon hoax site regarding a waving flag holds up, that could revolutionize our understanding of the history of space flight.”

      • Yes, one of the truly scary things out there is a possible drying out of the Amazon basin with the associated release of carbon from decaying tropical forests.

  52. “While it may be true that Judith intended this blog to be a place where climate science was strengthened in trials by fire, its impact so far has been to bury the field under garbage (I believe that Judith has a T-shirt with a related theme). ”

    This is one of the nastiest, misguided claims it’s been my displeasure to read here. Congratulations on your breathtaking incivility. Talk about garbage.

  53. JC,

    Can you please state for the record what *specifically* you found “sufficiently important” about this “that we should start talking about” it?

    Thanks in advance.

    • Thingsbreak, I am starting a new thread tomorrow to discuss blog related issues that you, chris and fred have raised

      • I appreciate that you’re going to post about some of the meta-issues raised in this thread, and I am genuinely looking forward to it.

        That’s a different kettle of fish from what I’m asking, though.

        You called this presentation was “important”, exclaimed, “wow”, that it could “revolutionize AGW science”, etc. You created a “technical” blog post about it.

        Yet there are no data or analyses to discuss. You’ve offered exactly nothing in terms of specifics of why you personally believe this is so important and potentially revolutionary. Other than “not IPCC”, what explicitly are you saying is “important” about this?

      • I think this dicussion is 1000x more important than say Cool Dudes — the anti-White Male thread.

      • JC:

        What from a science perspective (not “he used to be a colleague” and not “Not IPCC”) from Salby’s presentation do you feel was worth saying wow, it’s so important that we should talk about it, it’s potentially revolutionary to the field, etc.?

        (I apologize if you actually managed to answer this at any point during the last couple of days. I understand that your time is precious and you choose which comments to respond to with great care…)

      • I’ve got a pretty satisfactory answer for your question, tb, from Judith’s response to your question, as quoted in her ‘Editorial Decision’ thread., two whole days ago. What about her response there fails to satisfy you?

      • Well, I’ve considered some more, and I can see that with your focus on ‘he used to be a colleague’ and ‘not IPCC’ instead of ‘potentially revolutionary’ you are likely to be insatiable.

        Enjoy your repast. Digest at leisure.

  54. Does anyone know which journal the paper will appear in? I suspect it may be E&E.

    • Take a look at salby’s web page, and see what journals he publishes in, definitely NOT E&E

      • I have looked at Salby’s publication record (which is very good); however the carbon cycle seems rather outside his primary expertise, so it wouldn’t be a surprise if he were to depart from his normal choice of journal. It is well known that volcanic eruptions and e.g. ENSO are well correllated with the growth rate; it is also well known thatthis tells you precisely nothing about the long term trend as the differencing operation used to obtain the growth rate obliterates the long term trend. The mass balance argument is also well known, and established beyond reasonable doubt that the natural environment is a net sink, and hence is opposing the observed rise. As a result I would be very surprised if a mainstream climate journal would accept it if its conclusions are as suggested here (I wouldn’t be at all surprised if E&E accepted it though).

      • It isn’t hard to get published in a non-climate journal where the editor likes mavericks. And in a non-climate journal, the editor has to depend on suggested reviewers by the author (eg, his friends) and doesn’t know where to find a real expert reviewer. So occasionally, climate contrarian papers that have no scientific standing can actually get in print in respectable journals.

      • No I have to differ with you, Mister M. It’s simply not possible for climate contrarian papers that have no scientific standing to find their way into print in respectable journals. Because the moment such an event might have been deemed to occur the journal concerned would no longer be held to be respectable. You seem to losing the plot, in more than sense of the word.

      • dikranmarsupial –
        I have looked at Salby’s publication record (which is very good); however the carbon cycle seems rather outside his primary expertise, so it wouldn’t be a surprise if he were to depart from his normal choice of journal.

        Salby IS an atmospheric physicist with apparently longer experience with saellite data than most climatologists. And I think if you look carefully at his pubs, this isn’t all that far from what he’s done for the last 25 years or more.

        You’re picking nits where ther are none.

      • He’s wrong anyway. It doesn’t matter that he’s an atmospheric physicist. When someone is this wrong discussion invariably turns to finding out how it could happen.

        Dikranmarsupial suggests in this case it could be because the carbon cycle is outside his primary area of expertize.

      • lolwot –
        Dikranmarsupial suggests in this case it could be because the carbon cycle is outside his primary area of expertize.

        Well, since his paper has been peer reviewed and will be published, I would suggest that that reason is noting more than another form of hand waving dismissal with no validity.

        Not saying Salby is right – but you lack any evidence that he’s wrong so your eagerness to trash him just confirms your CAGW Church membership.

      • Peer review is no guarantee that a paper is correct, never has been, never will be. It is the only the first step in the acceptance of a paper. The next step is to wait to see if there is any correspondance published, and then a wait to see if it collects citations. Essenhigh’s paper published in Energy and Fuels is aa good example. It also purports to show that man is not responsible for the rise in atmospheric CO2 (in this case because the residence time of CO2 is only about 5 years). It is a peer reviewed paper, in a respectable journal, but it is nevertheless wrong. It wouldn’t have been published in a mainstream climate journal as the reviewers would have known why residence time is irrelevant (it is adjustment time that is relevant).

        Now as it happens, I did more that wave arms, I gave a specific argument that demonstrates that anthropogenic emissions are responsible for the observed rise in atmospheric CO2 (the mass balance argument). This same argument also explains why Essenhigh’s paper was also wrong.

        It is best to avoid throwing round insults (“CAG” church membership”) as it doens’t help your argument when it turns out that there was evidence presented that Salby was wrong, you just didn’t see it.

      • scepticalWombat

        Jim Owen says
        Well, since his paper has been peer reviewed and will be published, I would suggest that that reason is noting more than another form of hand waving dismissal with no validity.

        On what basis do you say it has been peer reviewed and will be published? It is now over 12 months from the talk and Salby has already indicated that he was having trouble with the review process.

  55. There is no reason to believe that carbon sinks have a linear relationship to temperature. A 1C warming now would allow for a lot less plant growth then a 1C warming when the world is half covered with ice.

  56. The realistic discussion of this would be rather boring to many. Ie where Salby has gone wrong, the multiple lines of evidence that CO2 rise is human caused, etc.

    But the fantasy discussion – always premised on the exciting idea that the subject might prove man-made global warming wrong – is popular to a certain clientele.

    Dr Curry seems to provide just enough information to facilitate the exciting fantasy discussion, but not any more that might risk the boringly realistic discussion happening.

    As an example I note that the discussion is predicated on a summary by Andrew Bolt and not a summary by Dr Judith Curry. I realize the podcast and abstract was not sufficiently lucid enough that a summary could be quoted from Salby, but letting Andrew Bolt frame it? Really?

    Makes things very difficult because as these fantasy discussions go it never matters what the scientist is actually claiming, only what the skeptics interpret them as claiming.

    Lets assume Bolt fairly summarizes Salby (if we have to review that then this thread is trashed anyway).

    In which case Salby has made a number of errors. The prime error being that he’s confused causes of short term variation with causes of longterm variation. He’s pulled a bit of a McLean ENSO-temperature error here. Salby hasn’t raised anything new, he’s just misinterpreted things that are already known.

    Second he wrongly claims isotopes are the only evidence for CO2 rise being human caused. In fact there are multiple lines of evidence and in sum it’s overwhelming. Salby doesn’t appear to have considered anything other than isotopes.

    You don’t need to be an expert on the carbon cycle to understand this or where Salby has gone wrong.

    • lolwot,
      Your gift of prophecy is one that we should all appreciate more.
      Please tell us what else you can already fully understand and critique before you read it.
      Have you considered a career in financial management and investment advisory services?

      • If there’s enough information for Andrew Bolt to summarize it and enough information for this thread to exist to discuss it, then why do you think there isn’t enough information for me to conclude Salby is wrong?

      • Because there’s considerable doubt that you’ve ever been right?

    • Anything related to cimate change framed by Andrew Bolt can almost be garanteed to be wrong.

      Most Australian readers would know to take a Bolt pronouncement with a massive dose of salt, but Judith may not be aware of his well-known proclivity for his …um….interpretation… of facts.

  57. Amusing to see E&E derided again. Wait and see my friends…….Not so long ago, EE “isn’t in ISI so must be no good”, Whoops now it is. So it must be good, yes? And is Salby all about Beck, EE author scoffed at by everyone? Jo Nova links to Quirk, guess where his papers were published. “Always be polite to young ladies, you never know who they might become”

  58. Dr. Salby’s states that CO2 response to temperature is much higher than the ice core indicates. This does not mean that the mass balance will not or does not work. I thnik that it is not much ado about nothing, but may be more important on how we model sinks, and even how we veiw long term CO2 temperature changes. I thnik we need the paper.

  59. Looks like we could all learn something from the IPCC report afterall. Interannual Changes in the Carbon Cycle

    “The atmospheric CO2 growth rate exhibits large interannual variations (see Figure 3.3, the TAR and The variability of fossil fuel emissions and the estimated variability in net ocean uptake are too small to account for this signal, which must be caused by year-to-year fluctuations in land-atmosphere fluxes. Over the past two decades, higher than decadal-mean CO2 growth rates occurred in 1983, 1987, 1994 to 1995, 1997 to 1998 and 2002 to 2003. During such episodes, the net uptake of anthropogenic CO2 (sum of land and ocean sinks) is temporarily weakened. Conversely, small growth rates occurred in 1981, 1992 to 1993 and 1996 to 1997, associated with enhanced uptake. Generally, high CO2 growth rates correspond to El Niño climate conditions, and low growth rates to La Niña (Bacastow and Keeling, 1981; Lintner, 2002). However, two episodes of CO2 growth rate variations during the past two decades did not reflect such an El Niño forcing. In 1992 to 1993, a marked reduction in growth rate occurred, coincident with the cooling and radiation anomaly caused by the eruption of Mt. Pinatubo in June 1991. In 2002 to 2003, an increase in growth rate occurred, larger than expected based on the very weak El Niño event (Jones and Cox, 2005). It coincided with droughts in Europe (Ciais et al., 2005b), in North America (Breshears et al., 2005) and in Asian Russia (IFFN, 2003).”

  60. So, Murry Salby is suggesting that recent warming has induced an increase in CO2 levels rather than the other way around?

    However, past interglacial periods have been slightly warmer than this one. The Eemian period (the previous one ~100k yrs ago) was a couple of degrees warmer, sea levels were a few metres higher, but CO2 levels were still below 300 ppmv .'s_atmosphere

    • Do you unreservedly believe anything Wikipedia says on subjects related to climate change?

      • Peter317,
        Not unreservedly. Wiki is an extremely useful resource and its often the first place I’d look, but it does pay to double check. For instance if I’d like to provide a reference that CO2 levels are now much higher than in the Eemian period I would give:
        And as for conditions themselves 100k yrs ago:

        Have you any evidence that Wiki have it wrong? If so, I’d be happy to edit the Wiki entry if you can show credible evidence that they have.

      • Have you any evidence that Wiki have it wrong?

        I didn’t say Wiki had it wrong, just that it’s not to be trusted – and I tend to take with a pinch of salt any climate-related postings which reference Wikipedia articles.
        A certain gentleman with the initials WC appears to spend an inordinate amount of time editing Wikipedia articles – so much so that it’s a wonder how he manages to get anything else done.

      • Peter, here the plot of the Vostok ice cofe CO2 vs. temperature (proxy):
        That is around 8 ppmv/degr.C

        A similar plot is available for the MWP-LIA transition from the higher resolution (40 years average gas age) Law Dome ice core, again about 8 ppmv/degr.C.

        The current short term response of the CO2 sink rate on temperature variations is about 4 ppmv/degr.C around the trend.

        Conclusion: temperature is not the cause of the 100+ ppmv increase of the last 1.5 century,

      • Ferdinand
        Re: “about 4 ppmv/degr.C”
        Is that the net or the gross variation?
        e.g Spencer finds “7,100 mmtC/deg. C.” in the southern ocean.

        I understood Selby to say that natural sources and sinks are much larger, vary much more, and have much higher uncertainties than anthropogenic emissions.

        See NASA on Carbon Cycle for conventional perspective.

        See also Jim Goodrich on Atmospheric Carbon Dioxide variations

        “This increase fluctuates 6.3 ppm on an annual cycle with the highest in May and the lowest values in October.”
        These annual variations are clearly temperature driven. The longer term variations also look much closer to temperature variations than anthropogic variations. Spencer shows variations from e.g. from 0 Gt/year to 7.8 Gt/year.

      • David Hagen,

        Firstly its important to remember that, globally, there is no such thing as summer and winter. All UK cricket lovers will know that the summer months in Australia are the winter months in the Northern Hemisphere.

        Still, the Northern Hemisphere does dominate as that’s where most of the land is and that’s where there are the most trees and other vegetation.

        Yes, there is a noticeable annual sinusoidal variation, which as you say produces a maximum in April and a minimum in October. So, it looks like you might be shooting yourself in the foot with this argument. Doesn’t it show that the warm NH summer months are causing a reduction in CO2 rather than an increase?

      • tempterrain,

        When is the maximum for the global temperature? I think in July.

        Do you know when the maximum is for the average sea temperature?

      • I would say later. Sept/Oct maybe?

      • tempterrain
        Conventionally CO2 is driven by N Hemisphere biomass. However, Spencer probes the possibility that it is actually driven by the southern hemisphere ocean. The highest CO2 in May would indicate that “summer down under” dominates, not the No. hemisphere growing period. (I lived in Oz for 9 years, so appreciate the importance of proper orientation.
        So I encourage you to check out the phase relationships between CO2 variations, the ocean’s thermal lag and solar variation, and see who’s “dancing” and why! I see the case is still open – and trending towards greater natural variation!

      • Annual variation in CO2 mixing ratios in the southern hemisphere are about nothing. The long term increase in the southern hemisphere lags that in the north by a few years, as would be expected if the excess is being driven by emissions in the north. See the

        Can that one.

      • Doesn’t it show that the warm NH summer months are causing a reduction in CO2 rather than an increase

        Think about it. There’s a lot more land in the NH, therefore a lot more vegetation to soak up the CO2 in the (NH) summer months. The SH has more ocean, therefore more outgassing of CO2 during the (SH) summer months. The tropics are rather neutral on yearly timescales.
        So yes, a decrease in CO2 during the NH summer is to be expected.
        And, overall, an increase in the long-term average CO2 concentration is to be expected with warming.

      • And thus there IS a global summer and winter as
        shown by the wiggle in the conc co2 curve.

      • The global temperature varies over the year with about +/- 0.5 degr.C, mainly due to the NH, which has most land. I had calculated a global CO2 variation of about 5 ppmv, but have no problem with the 6.3 ppmv of Roy Spencer.
        That means that the short-term (seasonal) influence of temperature on CO2 levels is about 6.3 ppmv/degr.C.
        From ice cores (even relative high resolution ice cores like Law Dome) we see an 8 ppmv/degr.C influence on very long periods. Thus the recent warming may be responsible for maximum 6 ppmv since the LIA (~0.8 degr.C rise), the rest is from human emissions.

        Indeed we only have a rough idea of the variability and height of the different natural inflows and outflows, but we have a pretty good idea about the total of all natural inflows and outflows together, which is a net sink over the past 50 years, with a natural variability of +/- 1 ppmv around the increasing trend in sink capacity. The current emissions at 4 ppmv by far exceed the increase in the atmosphere at 2 ppmv, including its variability.

      • Ferdinand
        Re: “maximum 6 ppmv since the LIA (~0.8 degr.C rise), the rest is from human emissions.”
        Except that does not account for the total sources and sinks, only for the difference. See Selby on how actual sources and sinks are much larger, and the apparent CO2 is only the net difference. The fact that it varies much much more than the anthropogenic emissions indicates that the natural trends dominate the CO2 variations, and probably the decadal and centennial trends as well. e.g. see Loehle & Scafetta (2011). for a separate analysis .

        Check out the correlation of CO2 variations with anthropogenic vs with temperature, volcanoes, enso, PDO/AMO, Hale cycle, galactic cosmic rays, the 1480 year cycle etc. etc. I think you will find that correlations of CO2 with natural causes are much higher than to anthropogenic emissions.
        As before, cAGW “not proven” with growing evidence that natural causes dominate.

      • You are assuming that the response to low frequency components is the same as that to high frequency components. On what data do you base this assumption?

      • The data from ice cores show a 8 ppmv/degr.C sensitivity for (very) long periods (centuries to millennia), while over the past 50 years, the sensitivity of the year by year variability in sink rate around the trend is about 4 ppmv/degr.C. The seasonal variability gives globally a change of 5 ppmv/degr.C.

        There are no data for mid-long periods (decades to centuries), but it would be quite strange to see a huge change in sensitivity for such periods. Even if that was right, it would show up in medium resolution ice cores.

      • Yes, I would be interested in seeing an explanation of how the sensitivity could be O(10 ppmv/K) at both interannual and Milankovich timescales, but O(100 ppmv/K) at decadal to century timescales. That explanation would take some creativity, I think.

      • J,
        The explanation is easy. We don’t know atmospheric CO2 variations at ‘Milanković’ timescales. There are many problems with CO2 data from ice cores (bubbles not gas-tight over 1000s of years, contamination, dating…).

      • Sure. If you throw out all the data that could contradict your hypothesis, then it can’t be falsified.

        Virtually all actual scientists working in this field accept the ice core measurements. The model being debated here would imply truly massive swings in CO2 between glacial and interglacial conditions (on the order of 1000 ppmv fluctuations). There is no evidence for that.

      • J,
        Just given the massive changes in biomass volume etc, especially between glacials and interglacials, how do you explain the apparent lack of massive swings?

      • J,

        I don’t completely throw all the ice core data out. Tempearature is likely pretty accurate. Dust too. Dating is somewhat problematic.

        But gas data can not be good for physical reasons. It’s simply not plausible.

      • Just given the massive changes in biomass volume etc, especially between glacials and interglacials, how do you explain the apparent lack of massive swings?

        There are swings of approximately 100 ppmv. This corresponds nicely to what would be expected from models (see, e.g., the EPICA Challenge) and is not unreasonably different from the sensitivity observed at shorter time scales, as Ferdinand Engelbeen noted.

        Lots of things change between the glacials and interglacials, and some of them have opposing effects on carbon fluxes. I’m not going to try to track down the latest and greatest on this, but a 2002 paper by Brovkin et al. shows that, at the last glacial maximum:

        * The atmosphere held ~400 Pg carbon (compared to ~600 preindustrial / interglacial)

        * The terrestrial carbon pool (soils and vegetation) held ~1300 Pg C (versus ~1900 preindustrial)

        * The ocean held ~40,100 Pg C (versus ~38,300 preindustrial).

        So, basically, during a glacial the land loses carbon, the atmosphere loses carbon, and the ocean gains carbon. I don’t know if that picture has changed in the past decade.

      • Edim,

        Most of the objections against ice cores I have read were based on the papers of Jaworowski/Segalstad of 1991. Most of the objections were already refuted in 1996 by the work of Etheridge e.a. on three ice cores at Law Dome.

        There may be some minor problems left:
        – A small fractionation of the smaller molecules at closing time, but for CO2, that is less than 1.2 ppmv/200 ppmv.
        – Migration of CO2 through the ice core: in “hot” (-23 degr.C) ice cores: a broadening of the resolution with 10% to 100% at depth, that means that the resolution is 22 years to 40 years instead of 20 years for the Siple Dome ice core. But that doesn’t change the average level!

        There is no migration in the “cold” (-40 degr.C) Vostok and Dome C ice cores over 420,000 and 800,000 years. If there was the slightest migration, the nice ratio between CO2 levels and temperature (proxy) of 8 ppmv/degr.C over glacials and interglacials would fade over time for each 100,000 years period further back.

      • J,
        You said: “The model being debated here would imply truly massive swings in CO2 between glacial and interglacial conditions (on the order of 1000 ppmv fluctuations). There is no evidence for that”

        But then in your reply to me, you said: “Lots of things change between the glacials and interglacials, and some of them have opposing effects on carbon fluxes.” etc etc

        I think you may have answered your own question there.

      • Ferdinand, why is land use change and deforestation not the most important change in all this?

        The addition of so many billions of people and the deforestation, desertification, urbanisation etc that followed, is surely the most massive change the system has had.

    • It’s funny that you have to even pose that first sentence as a question.

      As usual we are guessing at what the exact claim is. I decided to just go with Bolts interpretation as the official skeptic line on this matter – ie that Salby is claiming that the evidence for CO2 rise being human caused has been refuted – but the downside is that even if I successfully prove that wrong skeptics will claim I have errected a strawman because Salby never said that…(even though that’s what half the skeptics “took home” from it)

      Such is the waste of time refuting these vague claims

    • We don’t know the Eemian CO2 concentrations. We only have very crude estimates, IMO. If it was really a couple of degrees warmer (I believe it was), then I expect that the CO2 concentration was higher than today (very likely).

      • That’s not what the ice core records show.
        They show less than 300ppmv

      • You didn’t listen to the podcast, did you.

      • I know. It’s amazing that people believe it. Bubbles in ice are air tight over 1000s of years? There are other problems as well (contamination, dating…).

      • I mean gas-tight or sealed.

      • Edim,

        If ice cores weren’t gas tight, how do you explain that one still finds 100 ppmv CO2 difference between warm and cold periods, each warm period separated by some 100,000 years cold.

        If there was even the slightest migration, wouldn’t the differences have flattened to one long average of 210 ppmv (90% of the time at 200 ppmv, 10% at 300 ppmv). Or worse, we should see that the current high level of near 400 ppmv migrates all the way to the bottom of the ice core?

      • How do they know it was a warm period or cold period? There is much plasticity and elasticity in ice and pressure also changes it.

      • oxygen isotope ratios among other things

      • Thank you, but how accurate is it? With archeology they have radiocarbon dating but often when you read or follow a story in archeology they don’t seem to put much faith in the radiocarbon date. I hope its not CO2 levels or it would just be circular.

      • No, it is independent. OTOH, that’s kink of a how does Eli know that Judith Curry exists question.

      • Ferdinand,

        I don’t have an explanation for that. I would have to think about it and do some research. There could be many explanations (absorption, diffusion, chemical reactions, clathrates…). I am just speculating, but various artifacts are not to be dismissed.