Monday, July 1, 2013

Swedish scientist replicates Dr. Murry Salby's work, finding man-made CO2 does not drive climate change

Swedish climate scientist Pehr Björnbom has recently replicated the work of Dr. Murry Salby, finding that temperature, not man-made CO2, drives CO2 concentration in the atmosphere. Dr. Björnbom confirms Salby's hypothesis that the rate of change in carbon dioxide concentration in the air follows an equation that only depends on temperature change, detailed in his report Reconstruction of Murry Salby's theory that carbon dioxide increase is temperature driven [Google translation].

Dr. Björnbom discusses his findings in this post from The Stockholm Initiative [Google translation + light editing]:

Murry Salby, climate science innovator who challenges established views

Murry Salby is a highly qualified and well-respected professor, academic teacher, and climate scientist. He has a series of innovative talks challenging the leading circles representing the IPCC sanctioned culture of consensus in climate science. He presents startling research that fundamentally questions the established views of the IPCC consensus. An important hypothesis that he advances is that the atmospheric CO2 rate of change is a function of only the global temperature changes and that this may explain the increase in carbon dioxide from pre-industrial times. This result was I able to reproduce, in a report given here.

One of the big talking points in climate science circles is interest in Murry Salby's lecture in Hamburg recently:
It is in this lecture he presents the hypothesis that the rate of change in carbon dioxide concentration in the air follows an equation that only depends on temperature change . There is enough information in the preferred order to be able to reconstruct Murry Salby's theory in detail, as I have done in the report Reconstruction of Murry Salby's theory that carbon dioxide increase is temperature driven . My reconstruction can be summarized in the following figure where the projected path of carbon dioxide compared with the observed from Mauna Loa since 1959 and before that carbon dioxide levels from an ice core.
Figure 1
The correspondence between the calculated and observed values ​​is excellent if not perfect. It should be noted that Murry Salby made ​​a much more detailed analysis than me with a thorough discussion.
The Murry Salbys theory agrees well with the observed data is of course no guarantee that the theory is also consistent with reality. But this shows that the arguments given in the IPCC reports are not as solid as is often claimed. I have considered these arguments in a previous blog post Is the IPCC argument for carbon dioxide increase due to human emissions sustainable? . There are other theories that give similar results as in the figure above, such as that of Dr. Gosta Pettersson.
What my reconstruction, however, quite clearly shows is that Murry Salby's reconstruction results are reliable. Murry Salby is on firm ground when he says that his hypothesis agrees with observations of how carbon dioxide levels have increased since 1850.
This is not the impression you get when you read the title of a blog post by a Swedish professor of climate blog UI, by a layman in climate science, as he is a specialist in artificial intelligence: "Salbys strained relationship with the truth." But reviews the blog post closer you get to say that the professor in question throw stones in glass houses. None of the professor's points of attack on Salbys lectures in Hamburg audit Salby's analysis. One, on a published map , I have included in annotating # 30 in last week's blog post . The second point of attack argues that Professor Murry Salby's criticism of climate models are inaccurate. But, unfortunately for the professor, the same day he published his blog post  so it came very known German climate scientist Hans von Storch with a similar criticism as that of Dr. Salby.
Murry Salby is Professor at the Department of Environment and Geography - Environmental Science from Macquarie University in Australia. He has a formidable list of publications , especially the part related books:
Salby, M., 1992: The Atmosphere. In Climate Systems Modeling, K. Trenberth Ed. Sponsored Jointly by UCAR and the Electric Power Research Institute (EPRI), Cambridge University Press, 53-115.
Salby, M., 1996: Fundamentals of Atmospheric Physics. International Geophysics Series, Academic Press, pp. 628. 2nd Printing (2005)
Salby, M., 2002: Planetary Waves. in Encyclopedia of Physical Science and Technology, P. Crutzen Ed. Academic Press, 12, 357-371.
Salby, M., 2003: Fundamental Forces and Governing Equations, Chapter 2, in Handbook of Weather, Water, and Climate: Dynamics, Cliimate, Physical Meteorology, Weather Systems, and Measurements, T. Potter and B. Colman, eds. (Wiley-Interscience, Hoboken NJ, 2003), 7-20.
Salby, M., 2009: Fundamentals of Atmospheric Physics. International Geophysics Series, Academic Press, 2nd Edition (In preparation)
The latter book is now published, the list is not fully updated. I myself have read the textbook at postgraduate level Fundamentals of Atmospheric Physics in 1996 which is very respectable. Murry Salby appears to be very knowledgeable and competent.
From the beginning, in 2011, there was only one audio output (a podcast) from Murry Salby's lecture. But his thinking was so startling that it led to publicity. Judith Curry wrote a blog where she discusses a news article in the Herald Sun Andrew Bolt about this lecture.
Judith Curry begins her blog post:
I just finished listening to Murry Salbys podcast on climate change and carbon. Wow.
She then takes up the published summary and enters Andrew Bolt's article about the lecture. Her as usual pithy concluding remark is:
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.” 
Judith Curry obviously got a lot of criticism on her blog for her acclaim of Murry Salby's lecture, which she took up in her subsequent blog posts. Here she responds to a comment:
Can you please provide for "the record" what you * especially * found that is "sufficiently important" in this, "we should start talking about" it?
Thanks in advance.
JC comment:  The fact that Murry Salby is a former colleague of mine and definitely a scientific straight shooter initially caught my attention on this.  If correct, his hypothesis has far reaching implications on both AGW science and policy.  His presentation was extremely lucid and well done (even without availability of the plots.)   The topic he addresses was one that I thought was squarely in the “what we know with confidence” category; this presentation synthesizes and opens up issues at the knowledge frontier on this topic.   Fascinating stuff.  So if you are irritated that “deniers” will use this talk (and the fact that I featured it on my blog) as ammo in their war against CO2 stabilization policy, well that is too bad.  I for one am not going to let your irritation get in the way of having a good discussion here where we all stand to learn something.
This is well said by Judith Curry, as probably everyone who has a sincere interest in climate can agree with.



  1. "...the rate of change in carbon dioxide concentration in the air follows an equation that only depends on temperature change."

    What kind of statistical model are we talking about? ARIMA? Polynomial cointegration?

    No, simple correlation.

    The data represent time-series, so spurious correlation must be excluded. Econometricians do this by using cointegration rather than correlation.

    Does CO2 concentration polynomially cointegrate with global temperature during the period 1880–2007 and thus support the anthropogenic interpretation of global warming during this period?

    An Israeli group concluded, "We have shown that anthropogenic forcings do not polynomially cointegrate with global temperature and solar irradiance. Therefore, data for 1880–2007 do not support the anthropogenic interpretation of global warming during this period."

    Reference: Beenstock, Reingewertz, and Paldor Polynomial cointegration tests of anthropogenic impact on global warming, Earth Syst. Dynam. Discuss., 3, 561–596, 2012.


    In my opinion, until Salby and Bjornbom collaborate with statisticians/ econometricians familiar with cointegration, they cannot falsify the hypothesis that the correlation they have found is spurious.

    In fact, by integrating the observations, they have gone in the wrong direction. The first step in cointegration analysis is to take first differences.

    In my opinion Beenstock et al have already demonstrated that GHG are not coointegrated with observed warming.

    Salby and Bjornbom have demonstrated spurious correlation using more or less the same inappropriate statistical methods as the proponents of AGW.

    1. Thanks for your good points & reminding me about this paper, which I highlighted the day it was published here:

  2. Frank WaltersJuly 2, 2013 at 12:16 AM

    "In fact, by integrating the observations, they have gone in the wrong direction. The first step in cointegration analysis is to take first differences."

    As you like it. This is not spurious.

  3. There is another consequence of Salby's observations which has not yet made its way to the fore. The relationship imposes a requirement that the greenhouse effect of added CO2 to the atmosphere is necessarily small, or even negative.

    The reason is that the temperature-CO2 relationship establishes a positive gain between temperature and CO2. I.e., a temperature rise leads to a rise in atmospheric CO2.

    If, in addition, a rise in CO2 leads to a substantial rise in temperature, then there is a positive feedback loop dynamic. A temperature rise releases more CO2, which increases temperature, which releases more CO2, and so on, ad infinitum.

    Without some mechanism to arrest the mutually reinforcing dynamic, CO2 and temperature would continue increasing together without pause. With an arresting mechanism, the system would either peg at a boundary, or engage in a limit cycle, ping-ponging between boundaries. With strong mutally reinforcing feedback of the type required to induce significant warming from CO2, the limit cycle would be at relatively high frequency, and we would see large variations in CO2 and temperature over short intervals.

    We do not observe such behavior. It follows that the effect of CO2 on temperature, i.e., the sensitivity or gain, is either very small (long limit cycles) or negative (no limit cycle, well behaved system).

    It is quite possible for there to be a negative gain between increasing concentration of atmospheric CO2 and warming of the surface. Don't get me wrong. The greenhouse effect undoubtedly exists - any retained energy flux has to pool up somewhere.

    But, there is no requirement that it be monotonic with concentration. Due to the interlocking reactions of the Earth's various systems, the sensitivity function could easily overall look like this. Though globally positive, it may be locally negative in the neighborhood of a particular climate state, such as that which prevails at the dawn of the 21st century.

    In any case, Salby's relationship is telling us is that we have nothing to worry about, in terms of surface temperature, from increasing CO2, even if we were responsible for it or had any control over it, which we aren't and we don't.

    - Bart

    1. Thanks again Bart

      Reminds me of Monckton's discussion of feedback gain factors, that a system with feedback gain above ~0.8 is inherently unstable, but the past billion years of Earth's history instead indicate relative stability.

  4. The physicist Richard Feynman told his students, quite some time ago, that it doesn't matter how smart or powerful you are, if your hypothesis is contradicted by the empirical data, you are in dire need of a new hypothesis.

    In the case of the anthropogenic global warming hypothesis the co2 increase brought on by human activities (mostly due to burning fossil fuels) causes global warming. The contradiction is that there is no evidence that co2, neither over geologic periods nor currently, impacts global warming. In fact, over geologic periods it is clear that temperature variation brings on, hundreds of years later, very similar variations in co2 volume. And co2 has been 10 to 20 times higher than now in the more distant past, been much higher during two ice ages and going into once ice age, Finally, co2 at 20ppmv had already consumed 50% of the sun energy available to it. At 400ppmv there is basically no further energy available to co2 so no further increase in the global temperature. In fact, since about 2003 there has been a cooling. Both Russian and Japanese scientists, among others, such as Svensmark, are predicting long term cooling going forward.

    Moreover, ALL the computer models assume that the real culprit, water vapor, provides a positive feedback, bringing on a temperature increase 2 to 3 times that brought on by increased co2. This feedback assumption is (at best) dubious because NOBODY has a good understanding of climate feedbacks. In fact, cloud cover, one aspect of water vapor, very likely provides a negative (offsetting) feedback. Even hobbyist physicists should have long since understood that co2, representing 4/100 of one percent of the atmosphere volume, is not likely to be an influential factor insofar as climate.

    The total contribution of co2 caused by man's activities currently represents 5% of the co2 in the atmosphere. Therefore, what we control is 5% of 4/100 of one percent. (.05 X .0004 = .00002. The US is responsible for perhaps 30 percent of that amount, and Obama is promising to reduce that 30% by 17% over the next several years. (do the math!) The cost to our economy will be horrendous, and for absolutely no purpose. Both the democrats and Obama are going to be painted as charlatans in the history books, if there is any earthly honesty remaining by then.

    I have not yet heard one science based rebuttal of any of this information. All (so-called) rebuttals rely on non-science, "appeals to authority" or mumblings of "consensus" or such nonsensical stuff as psychoanalyzing skeptics. Even the infamous Michael Mann ("hockey stick graph" author) responds to scientific criticisms, by asking whether the reader prefers to have their gall bladder taken out by a dentist. (If this doesn't arouse your suspicions you are indeed a potted plant.) I would not claim that Mann qualifies as even a dentist, for fear of law suits brought on by both Mann and the dental association.

  5. Why have levels been around ~300ppm for the last 3 million years, while higher levels existed in the past ?

    Because the data passed through a filter (ice cores) that clipped the peaks.

    Until 1985 most studies of CO2 in gas inclusions in pre-industrial ice indicated that CO2 concentrations (up to 2450 ppm) were higher than the current atmospheric level. After 1985, lower pre-industrial CO2 values were reported, and used as evidence for a recent man-made CO2 increase.

  6. You'll let us know when this paper gets peer reviewed, right?

    1. Yes

      According to Monckton, Salby has three papers in press

  7. "Why have levels been around ~300ppm for the last 3 million years, while higher levels existed in the past?"

    This statistic may hold merely because of the low resolution of the data, not much better than 1000 years for some variables. And this level of precision is only recent.

    Data from peat bogs can be resolved by decade and when that is done, the estimate of CO2 concentration for some decades is much higher. The CO2 concentration appears to fluctuate in cycles. [Leaf stomata size is a proxy for CO2 concentration.]

    There are known problems with CO2 estimates from ice, the main one being the rate diffusion of CO2 out of glacial ice during various stages of its formation and burial at depth.

    Low resolution data has the effect of averaging the ups and downs over long periods. The estimate of 280 ppm that we have inherited from Keeling's work was one of several estimates available at the time. Some were well over 300 ppm.

    Recently there was a paper in Biogeosciences about outgassing of CO2 off the coast of California. There is a growing literature. Outgassing elevates CO2 but it is too early to say that annual CO2 outgassing is greater than CO2 from emissions. [Skepticism works both ways.]

    Uncertainty is a good reason not to base economic policy on the science as it stands today. Extrapolating a constant CO2 concentration of 300 ppm into the past is based mostly on ignorance about what the decadal and centennial fluctuations actually were.

    Like many other aspects of climate science we will have to wait until paleo-climate techniques have improved.

    I expect that in another 30 years or so we will know enough about the atmosphere, the oceans and the Sun to be able to account for these decadal and centennial variation in the climate.

    When I graduated back in 1958, the conventional wisdom was that climate had been stable since the Climatic Optimum 5000 years ago when global temperature was about 3 degrees Celsius higher than now. Sea level was about 2 meters higher at that time.

    In those days continents were believed not to moved laterally because plate tectonics was considered pseudo-science until 1970 or so. Humans were believed to have 48 chomosomes, 2 more than now.

    Science takes time, mostly time to overcome the prevailing dogmas. We won't know for 30 years which dogmas were wrong.

    That's a good reason not to wreck our economies and change out way of life.

  8. Salby's analysis of CO2 increasing in percentages with the increase of temperature makes more sense than the other way around. Much like the ability of water to hold more sugar and dissolve it easier when the water is warmer than when it is ice cold. Try it, put the same amount of sugar in hot and cold water and stir. (Water=air and sugar=CO2) To say otherwise (i.e. AGW)would be to say that the sugar gets wetter the more sugar you add.

    1. Sorry, you really need to lookup and understand Henry's Law, the relation between solubility and temperature.



  11. Sorry that I have to disagree here. Salby and Pettersson and others are completely wrong on this point.

    There are two main sources and sinks of CO2: oceans and vegetation. Vegetation is a difficult one:
    - During the seasonal cycle, there is a lot of CO2 absorbance in spring/summer and a lot of release in fall/winter. Mainly thanks to mid- to high latitude forests.
    - Interannual, there is a temporarely (1-3 years) lot of CO2 release with increased temperatures (and drought) from tropical forests and opposite from cooling + scattering sunlight from volcanoes.
    - Multi-decadal to multi-millenial, vegetation is an increasing absorber for CO2 (larger area) at higher temperatures, especially in more polar area's.

    For oceans it is quite simple: higher temperatures means more release of CO2 and opposite. But that is limited: not more than 16 ppmv increase in the atmosphere for 1°C increase in temperature. Far from the 100 ppmv we see today.

    The error by Salby (and others) is that they use the relative high correlation of the short-term variability of CO2 and temperature to integrate the increase of CO2 over the past 50 years, while that are two completely independent and even opposite reactions. And they forget the other variable: human emissions at twice the rate of the increase in the atmosphere...

    1. As well stated in a comment at WUWT:

      Ian Wilson says:
      August 12, 2013 at 7:42 am
      Allan MacRae says:
      August 12, 2013 at 3:48 am

      But if temperature primarily drives atmospheric CO2, not the reverse, why has atmospheric CO2 continued to increase even as there has been no significant warming of average atmospheric temperatures for the past ~10-20 years?


      I think the point is that d(CO2)/dt is proportional to temperature.

      This means that CO2 levels are proportional to the integral of temperature.

      I think you will find that even though the instantaneous temperature has recently flattened out, the integral of the atmospheric temperature with time is still rising. Hence, you would expect CO2 levels to still be going increasing.


    3. MS, Sorry for the late reply, seems that I have missed this one...

      If the CO2 levels are proportional to the integral of temperature, then there is no limit in the increase (or decrease) of CO2, as long as there is an offset from an (arbitrary) zero effect temperature. That is impossible to match with glacials and interglacials with duration of millennia and huge offsets either direction, neither with Henry's Law, which shows ~16 ppmv increase for 1°C temperature change. Any increase in the atmosphere above 16 ppmv will push more CO2 into the oceans, not reverse for 1°C sustained increase in temperature. Here a plot of fluxes and CO level for a sudden increase in temperature:
      No matter the real height of the fluxes, after a short time the fluxes of before the temperature increase are restored at a fixed increase of CO2 in the atmosphere.

  12. About the 14C decay from Pettersson: while the atomic bomb tests spike of 14C could be used as a good tracer for the fate of an excess of CO2 in the atmosphere, there is a huge problem for the part that is exchanged with the deep oceans: what goes into the deep oceans is the isotopic composition of today. What comes out is the isotopic composition of ~1000 years ago, thus long before the atomic bomb tests, or less than halve the 14C/12C ratio of the 1960 14CO2 peak.

    That means that the decay of 14CO2 in the atmosphere is much (more that 3 times) faster than the decay of an extra CO2 injection in the atmosphere. Thus the 14CO2 decay rate can't be directly used as proof for a fast decay of the human CO2 injection...

    1. the 14CO2 decay rate can't be directly used as proof for a fast decay of the human CO2 injection

      While not proof, it does provide strong evidence, unlike your mass balance argument which proves absolutely nothing.

      Where are the published papers finding from observations that isotope mixing from the deep oceans makes any significant difference to upper ocean isotope composition?


      From slide 13 on, but the whole lecture is very interesting.

      Main finding is that the 14C bomb spike is much lower near the upwelling places (between Chile and the Galapagos islands).



  15. "The correspondence between the calculated and observed values ​​is excellent if not perfect."

    This is interesting but you are _seriously_ over-stating the case.

    Plot the diff of both of those line then come back and post the result.

  16. If you can't explain the 'pause', you can't explain the cause...

    Neat, I'm gonna use that.

  17. New paper finding temperature, drought, and fires are the most important drivers of CO2 levels on inter-annual basis.

  18. Hi 'MS'. I don't have a 'clue' as to who you are, but your blog was linked to/by 'Tallbloke's Talkshop' so I came here.

    I'm a retired 'universal millwright' with an interest in 'climatology' since the UN declared that the 'ozone hole' was a risk to our survival. Who are you?

    I read nothing in your article WRT the absorption of CO2 by 'new water' generated by 'cloud droplet formation'. CO2 is the first gas to be absorbed of/from local gasses into pure water. Surely this 'forcing' is worth mention?

    The gaseous and solid 'states' of H2O preclude CO2 in their make-up, but the 'liquid phase' of H2O (water) permits a 'gaseous inclusion' (thus, 'fizzy drinks').

    IMHO this post ignores the value of 'new water' in the reduction of atmospheric CO2 in the 'rain' that adds to the 'pot' of CO2 in the oceans! Systems that 'decrement' atmospheric CO2 really do need to be mentioned 'alongside' the systems that 'accrete' atmospheric CO2.

    Best regards, Ray Dart.