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The carbon dioxide theory of Gilbert Plass

Filed under: — gavin @ 4 January 2010

Gilbert Plass was one of the pioneers of the calculation of how solar and infrared radiation affects climate and climate change. In 1956 he published a series of papers on radiative transfer and the role of CO2, including a relatively ‘pop’ piece in American Scientist. This has just been reprinted (as an abridged version) along with commentaries from James Fleming, a historian of science, and me. Some of the intriguing things about this article are that Plass (writing in 1956 remember) estimates that a doubling of CO2 would cause the planet to warm 3.6ºC, that CO2 levels would rise 30% over the 20th Century and it would warm by about 1ºC over the same period. The relevant numbers from the IPCC AR4 are a climate sensitivity of 2 to 4.5ºC, a CO2 rise of 37% since the pre-industrial and a 1900-2000 trend of around 0.7ºC. He makes a lot of other predictions (about the decrease in CO2 during ice ages, the limits of nuclear power and the like), but it’s worth examining his apparent prescience on these three quantitative issues. Was he prophetic, or lucky, or both?

To understand if Plass should get full credit, we need to see his workings. These are mainly outlined in two more technical papers in Tellus and QJRMS earlier that year. In today’s parlance, Plass calculated the change in top-of-the-atmosphere (TOA) radiative fluxes given a doubling (or a halving) of CO2 while everything else stayed the same. He then took that number and using someone else’s estimate of the sensitivity of the TOA radiation to the surface temperature, he calculated the temperature change that would be necessary to compensate. Converting from the units he used, the radiative flux values for a doubling of CO2 were 8.3 W/m2 and 5.8 W/m2 for clear-sky (no clouds) and averagely cloudy conditions (all-sky) respectively (and slightly larger and of opposite sign for a halving). The sensitivity of the TOA flux to surface temperature he used was around 2.3 W/m2 per ºC (equivalent to a temperature sensitivity of 0.4 ºC/(W/m2)). However, this is a ‘no-feedback’ estimate (allowing only the surface temperature to change with a constant lapse rate, but with no changes to water vapour, albedo or clouds).

Today, our current best guess for the forcing due to 2xCO2 is around 4 W/m2, and the ‘no-feedback’ sensitivity is around 0.3 ºC/(W/m2), giving an expected no-feedback temperature change of about 1.2 ºC, a factor of 3 smaller than the number Plass quoted, though since our number is for ‘all sky’ conditions, it would be a little better to compare it to his averagely cloudy number 2.5 ºC (so a factor of two higher). Note that Plass was a little casual in how he described his numbers and the ‘clear sky’ designation for the 3.6ºC number was not always made clear. However, Plass was well aware that the ‘no-feedback’ case was unrealistic and estimated that the water vapour, cloud and ice-albedo feedbacks would be amplifying, although he was not able to quantify them.

Moving now to the rate of change of CO2 in the atmosphere, Plass made a very good estimate as to how much human emissions of CO2 were increasing. His estimate was (again, in modern units) that then-current emissions were 1.5 GtC based on earlier estimates from Callendar, which actually was an underestimate. Our current best estimate for the anthropogenic emissions in 1956 is about 2.2 GtC. Given the increasing nature of the emissions, Plass then estimated that concentrations would rise about 30% by the end of the 20th Century. This however needs an estimate of how much of the emissions would be absorbed by the oceans and biosphere. Here, Plass has another impressive insight that the ocean chemistry would prevent quick uptake of the human CO2, a concept that wasn’t fully worked out until Revelle and Suess’s paper in 1957 (though possibly he may have been aware of some informal communications earlier). Plass actually assumed that none of the CO2 would be taken up in the short term. So his 30% growth estimate (the actual rise was 36%) was derived from an underestimate in emissions (and emissions growth) combined with an overestimate of the ‘airborne fraction’ (which is roughly 40% of total emissions).

Finally, his estimate of temperature rise of about 1ºC by the end of century follows from the two previous numbers, along with two further assumptions – that the climate is always close to equilibrium with the forcings and that of course, there aren’t any other factors changing. The first assumption affected by the substantial lag in the system because of the thermal inertia of the oceans, and of course, there are many more factors driving climate change over the 20th C. Plass can of course be forgiven for not knowing about the greenhouse impact of rises in CH4, N2O and CFCs (not realised until 1974), or the role of aerosol emissions (1970s), and indeed, he was fortunate that the net effect of all non-CO2 drivers is close to zero (though with significant uncertainties).

So Plass was correct about all of the big issues, but lucky that, in his quantitative estimates, the errors went both ways and end up pretty much cancelling out.

Eli has described this using Isaiah Berlin’s Hedgehog and the Fox metaphor – Plass being the Hedgehog who knows one big thing, and for whom the details are more incidental. I think this is a reasonable take, as long as it is realised that Hedgehogs are not always right, even though in this case he was.

The Fox in this case was another big name in atmospheric physics, Lewis Kaplan. He published a counter to Plass’s 1956 work in Tellus in 1960 (vol. 12, p204-208), and there was a “spirited” exchange of letters in 1961 (vol. 13, p296-302) (references for those of you with libraries – for some reason, none of the old Tellus volumes are online). His calculation used a different methodology, more up-to-date spectra but was different enough in approach and specifics to make a fair apples-to-apples comparison between the results hard to do. Nonetheless, Kaplan declared that “Plass’ estimate of a temperature drop of 3.8ºC due to a halving of [CO2] appears to be too high by a factor of two or three” and that “it would seem, then, that CO2 variations could not play a role in the ice-age cycle unless the changes were by an order of magnitude”.

The subsequent comment and reply are actually very reminiscent of recent disputes in climate science. Plass complains that not enough information was provided to replicate the analysis, that Kaplan used unjustified precision, that he wasn’t comparing like-with-like (all-sky with clear-sky), that he made unjustified technical assumptions, and that his overall conclusion was ‘misleading’ because of the neglected feedbacks (that neither of them had quantified). Kaplan responds that of course there is enough information to check his workings (in another paper), that it was Plass’ fault he compared the all-sky and clear-sky numbers, and that he has exaggerated the impact of the technical criticisms. Notably, Kaplan did not respond on the issue of feedbacks.

Looking over the exchange with a 50 year perspective, a number of things stand out. First, Kaplan does seem to have been closer to modern values in his calculation – Plass was out by a factor of two for the all-sky no-feedback case. I’m not really familiar enough with the details to be be able to tell why (perhaps someone can enlighten us in the comments). However, Kaplan was wrong about everything that has ended up mattering – CO2 does play a big role in ice age cycles (with a magnitude of change close to what Plass anticipated) and its growth today is climatically significant. Significantly, I can find no trace in the literature of any resolution of the technical issues raised in the letters. Resolution in Plass’ favour of the big questions came with further independent efforts as computers got fast enough to do the more complicated feedback problem, better observations, better spectral data and better paleo-climate information (particularly from the ice cores). In some sense, resolution of their technical differences would have been moot because that wasn’t the real issue. Of course, that would have been difficult to see at the time.

So, to summarize, Plass did have some key insights and in many respects was well ahead of his time. But he was also lucky.

Update: Stay tuned, it looks like there is another little wrinkle to this story…

158 Responses to “The carbon dioxide theory of Gilbert Plass”

  1. 1
    Andy Revkin says:

    Plass’s work also led to the first substantial media coverage of human-driven global warming, including a remarkable article in The New York Times that ends with a line that is entirely relevant today (brackets added):

    “Coal and oil are still plentiful and cheap in many parts of the world, and there is every reason to believe that both will be consumed by industry [and consumers] so long as it pays to do so.”

    I included a link to pdf of that article with this 2006 story on sifting reality from hype (of any sort):
    Here’s direct link:

  2. 2
    Andy Revkin says:

    Forgot to include link to this amazingly prescient Frank Capra look at climate science, which also was released around that same time:

  3. 3

    Thanks for another enlightening post. I do think that the historical depth and breadth of the science is important–and grossly under-appreciated.

    It seems that Plass’s case is parallel to Arrhenius’s in that both were right about the big picture, both had predictions that turned out to be correct, but both had some luck in terms of “error cancellation.” (Unlike poor old Claude Pouillet, whose calculation of the temperature of the Sun was blown up by the fact that Stefan-Boltzman was still yet to come!)

  4. 4
    CM says:

    Ah, good to have a history post again. Leaves me very idly wondering two things:

    What will RealClimate be saying in 2060 about today’s best estimates?

    And is there some way to cultivate a knack for making one’s errors cancel out (short of running model ensembles)?

  5. 5
    John E. Pearson says:

    Nice article. I took a couple of semesters of what was called “Modern Physics” (i.e. special relativity and QM for idiots) from Plass in about 1980. I don’t remember many of my teachers but I do remember him. He mentioned his work on CO2 in passing one day, but didn’t go into it. I still have the text book in which I scribbled that down. This set off a long running debate between me and my girlfriend at that time who doesn’t like cold weather and thought global warming would be a good thing.
    Plass was a good guy who cared about his students. It is funny now that he is considered an “alarmist” by the denialists. His public personna was meek and mild, although I suspect that he had a tougher side. The only thing I personally ever saw alarm him was when the Texas A&M Corps of Cadets (aka Corp Turds or “CT”s) would put up posters advertising the next “CT Beer Bust” on the physics department bulletin boards. Plass would grow visibly angry, stride over to the bulletin board, and tear down the offending material. During those times he radiated anger, but otherwise he was a mild mannered and quiet gentleman who was always in a suit coat and wore a bow tie, although he’d take the jacket off while sitting in his office. I have no knowledge of any physics students removing CT Beer Bust posters from other parts of campus and installing them up near Plass’ office in the physics building just to watch the fireworks.

  6. 6
    Eli Rabett says:

    It is important to understand that when hedgehogs are wrong they are nutty wrong. You can’t ever convince them of this, but you can ignore them. A good recent example of this is Qing Bin Lu at Waterloo whose hammer is cosmic ray shower formed electron attachment to PSC ice particles which explains everything about climate from ozone to global warming and, oh yes, is absolutely key in biology. We have seen many examples of this including, for example, Ferenc Miskolczi. Lindzen is well on his way.

    As far as Kaplan and Plass there is is story that Eli has shared with others about a friend who, when he has a problem, visits with two colleagues. One of them, the Nobel Prize winner (for serious) gives him the wrong answer but for the right reason, the other, almost equally famous given him the right answer with the wrong reason. Since they are unfailingly consistent in this he gets what he needs.

    The reason that hedgehogs who have the right big idea win out is that the other stuff that effects the problem, some goes up, some goes down and on average, averages out.

  7. 7
    Ike Solem says:

    Plass – wasn’t he the person who debunked the notion of CO2 saturation with respect to infrared in the Earth’s atmosphere? That came about due to his work with military technology – an understanding of how infrared was absorbed in the atmosphere was required for heat-seeking missile technology. A military spin-off, in other words – search Google Scholar for GN Plass and infrared.

    For a more comprehensive view, see Moller & Manabe 1961, Monthly Weather Review, “On the Radiative Equilibrium and Heat Balance of the Atmosphere.”

    It is a very challenging problem, however, to simulate the latitudinal distribution of the height of the tropopause, that of the temperature in the stratosphere, and the polar inversion in the lower troposphere. In order to do this it is necessary to build a model which has a high resolution (many levels) in the vertical direction and which includes the various thermal processes acting in the atmosphere, i.e., radiation, condensation, and the eddy flux of sensible and latent heat from the earth’s surfuce.

    Hence, at the time, without even the ability to accurately predict the current state of the atmosphere, let alone how it would change under forcing, those Plass – Kaplan estimates are just educated guesses that needed a lot of refinement. At the time (1961) the current status was something like this:

    Gowan computed the distribution of radiative equilibrium temperature of the stratosphere and obtained an increase of temperature with altitude by taking into consideration the heating due to the absorption of solar ultraviolet radiation by ozone as well as the effect of long wave radiation by water vapor. In the improved version of his computation, he also includes the effects of the the 15u band of carbon dioxide, the 9.6u band of ozone, and the absorption of solar radiation by water vapor. The equilibrium temperature of the stratosphere thus obtained increases with altitude and qualitatively coincides with observed features. Quantitatively, however, the temperatures are much warmer than those observed. This computation could be further improved by adopting recent observations of the extraterrestrial solar spectrum and the distributions of gases in the stratosphere as well as the absorptivities recently obtained in the laboratory.

    That latter laboratory work involved Plass and his co-workers, wasn’t it? That was the real contribution, I think.

    Manabe lays out the basic elements in sections 2 & 3, titled “Temperature change due to long-wave radiation” and “Temperature change due to the absorption of solar radiation.” He also mentions Plass:

    The dependence of absorptivity of this band on temperature is not always small. This was pointed out, for example, by Plass [51].

    Which again goes to show that the main contributions of Plass were in the area of understanding the pressure and temperature effects related to infrared absorption in the atmosphere:

    Although the mixing ratio of carbon dioxide is approximately constant with height, pressure as well as temperature vary with altitude. Therefore, the estimation of effective temperature involves cumbersome computations. (See, for example, Plass [51]).


    However, according to Goody [20], the 15u band of carbon dioxide has a rather strong heating effect at the tropopause. The reason for this strong heating could be found from a careful examination of Plass’ [51] results of the temperature change due to this band.

    The Plass article that Manabe cites is titled “The Influence of the 15u Carbon Dioxide Band on the Atmospheric Infra-Red Cooling Rate. (1956)”

    The main point here is that the science behind global warming wasn’t cooked up overnight, but is rather the result of detailed long-term efforts by hundreds of scientists over many decades. They first verified that the main actors with respect to long-wave radiation were carbon dioxide, water and ozone – and only by understanding the steady-state situation can you have any hope of prediction the effects of ozone destruction, fossil fuel-sourced CO2 additions, and the resulting changes in water vapor content and distribution. The first one-off guesses about the result of any such changes are interesting, sure, but it’s not some Einstein moment, I don’t think.

    As far as press coverage, well, I imagine the fossil fuel lobby wasn’t such a dominant force in discussions of climate during the 1950s. For example, you wouldn’t have reporters running around claiming that all droughts and floods are due to El Nino cycles in the pre-fossil fuel lobby era, I don’t think. And by the way… why is Australia getting hammered by floods during an El Nino, after suffering droughts during La Nina? Anyone want to suggest an explanation for this apparent reversal of normality?

    U.S. press coverage of climate science is as atrocious as it gets – and when they try to buck the trend and do a good job, their fossil fuel corporate owners simply fire them, as per the CNN science team.

  8. 8
    paulina says:

    Gavin: Nice synthesis!

  9. 9
    Eachran says:

    Another interesting comment for me for the start of my year. Dr Annan’s, and Hargreaves, paper on the upper bound for sensitivity and the economic implications was also very interesting.

    I have been following climate science for a few years now but have difficulty getting a solid grip on, or a feel for, the big picture because of the details.

    My field is principally economics and I have no problem following any of the work being done in economics. Much of the stuff is obscured by numbers but I think I know how to edit the stuff and there hasnt really been any theoretical progress since Adam Smith, Marx and Keynes.(Before any economists start to list what they believe is progress they need to remember that the dividing lines in the social sciences are becoming increasingly blurred and that behavioural sciences in general are almost certainly showing the way forward.)

    I have no problem with numbers : indeed we depend on them. But there is this tree and wood problem which is difficult to manage outside of ones field. But it needs to be managed so as to give the average Jo an opportunity to understand what he/she may have to vote for.

    It really doesnt surprise me that big picture thinkers in complex areas do well, multi-variate and multi-dimensional analysis is difficult and not many do it well nor can explain it simply, the problem is how to project the big picture to the population at large.

    Sorry no answers on that. Not yet, anyway.

  10. 10
    Spencer says:

    Plass told me that he had worked up these calculations in his spare time, out of curiosity; his day job was doing infrared calculations for Lockheed in connection, I suppose, with heat-seeking missiles. It shows how little interest people of the time had in greenhouse warming, which helps explain why the Plass-Kaplan exchange was noticed by very few (two exceptions: Revelle and Keeling, who like Plass were working in Southern California).

    Plass and Kaplan both left out not only clouds and H2O enhancement butr also what turned out to be the elephant in the room: upward transport of heat by convection of air(okay, the heat is mostly carried by water vapor, there’s that old H2O again). You can’t get a correct result if you don’t take that into account, as was first done by Manabe & Strickler in 1964.

    Well, not actually first. A remarkably prescient and entirely overlooked calculation including convection, predicting significant warming, was published by E.O. Hulburt in 1931, Physical Review 38: 1876-90.

    For details on all this see this historical site.

    Here’s another neat politics-related quote I ran across recently, not quite so old, although 1981 is still pretty far back:

    “The effects of CO2 may not be detectable until around the turn of the century. By this time, atmospheric CO2 concentration will probably have become sufficiently high (and we will be committed to further increases) that a climatic change significantly larger than any which has occurred in the past century could be unavoidable. To avert such change it is possible that decisions will have to be made (for example, to reduce anthropogenic CO2 emissions) some time before unequivocal observational ‘proof’ of the effects of CO2 on climate is available.” — T. Wigley & P. Jones, Nature 292: 205-08

  11. 11
    Spencer says:

    “This historical site” URL didn’t get through your posting system…

  12. 12

    The unabridged version of the original American Scientist article is available here:

    Thanks to Gavin for suggestions in cutting the print version and, of course, for his excellent commentary.

    David Schoonmaker
    American Scientist

  13. 13
    Andy says:

    Holey schmoley, it’s a small world. I believe Dr. Plass occupied a lab next to mine at Texas A&M in the mid-1980′s. While I was picking invertebrates out of samples of marsh mud, he and his graduate student had constructed a helium cooled laser that occupied an entire elevator shaft and upstairs room. If I recall correctly, his student had to learn how to use a metal lathe to manufacture some of the needed parts. I thought I was going over and above for my graduate degree (biblical plagues of mosquitos, etc.) until this student told me he had been working on his master degree, constructing this laser from scratch, for the last five years.

  14. 14
    Completely Fed Up says:

    “But it needs to be managed so as to give the average Jo an opportunity to understand what he/she may have to vote for.”

    The voting isn’t on the science.

    It’s done on the question: “Is there a problem with AGW”.

    There is.

    Voting from the public would be on what politicians they want and the politicians would have to vote on what methods they’d use to enact the requirements.

    What SHOULD be happening is the politicians saying “well, scientists, what if we do this that and the next thing on this timescale?”.

    But the money is still trying to make out the science isn’t firm so nothing should be done. And do you think THEY are wanting a vote?

    Heck no!

  15. 15
    Matthew says:

    This was good, and I saved it to my home repository of AGW stuff.

  16. 16
    Bean says:

    When it comes to understanding CO2’s naturally occurring and anthropogenic influence and effect on Earth’s climate, the public will not vote for politicians who increase their taxes because of what some early nineteenth century chemist (Arrhenius) or 1950’s physicist guessed at regarding climatology, a branch of science that didn’t even have a University degree at the time. What surely they will be more interested in is something recent and more relevant like Lindzen & Choi’s GRL article published in August of 2009.
    To summarize, the more GHG absorb heat in the atmosphere, the greater the flux rate of heat to space at the top of the atmosphere, meaning less warming than predicted by AGW theory. Hard data stating global warming will be less than one-sixth than that predicted.
    And to those who snivel at Richard Lindzen’s accomplishments, Michael Mann certainly does not. If fact quite the opposite, Richard Lindzen “contributes meaningfully to the scientific discourse” according to his December 31, 2009, WSJ article. Thus, one cannot simply ignore Lindzen’s research as some crank or skeptic who consistently is not “on message” when it comes to AGW theory. He’s gadfly in the AGW theory to be sure, but is also a first rate scientist. Who should the public take more seriously when considering global warming if it were put to a vote, Gilbert Plass or Richard Lindzen?

    [Response: The issue is not Plass vs. Lindzen, but rather Lindzen vs. pretty much everyone else today. - gavin]

  17. 17
    Eachran says:

    Well, Completely Fed Up, what you think should happen is all very well but what does happen is in general what people want to happen or are persuaded that it is in their best interests to happen.

    One of the distinguishing things about scientists as a group is that they tend to be aggressive with each other, with their subject or with the things that they believe themselves to be certain about. I would expect them to do that and would be disappointed if they didnt do that because if they were not aggressive then I would suspect the scientific method. I expect blood on the carpet.

    It seems that the apparently mild mannered Mr Plass was like that.

    That does unfortunately have unfortunate effects.

    One of them is screwing up on the PR. The unfortunate IPCC Chairman demonstrated that in The Guardian CiF today despite the fact that he is almost certainly correct in his views.

    I would be more optimistic and less authoritarian than you. There are lots of good people working in government who know the science and are doing their best : we need to support them.

    Even if it means paying the next retired CEO of Exxon USD400 million on retirement to keep his mouth shut.

    That’s politics, but it may save our skins. In any event what can anyone do with USD400 million.

  18. 18
    jyyh says:

    no idea on Australian flood but southern Brazil (about on the same latitude) has also had its share of increased moisture. is there a common ground?

  19. 19
    Edouard Bard says:

    Bonjour Gavin,

    Many thanks for this nice and interesting piece on the history of our field !

    A year ago, I participated as a member of the Habilitation committee of Jean-Louis Dufresne at the University of Paris 6 (he is a well-known climate modeler at ‘Laboratoire de Meteorologie Dynamique’ and served as an author of several chapters of the IPCC AR4). As an introductory section of his thesis, Jean-Louis has redone several calculations performed by several famous pioneers (Dufresne J.-L., « L’effet de serre : sa découverte, son analyse par la méthode des puissances nettes échangées et les effets de ses variations récentes et futures sur le climat terrestre. », These d’Habilitation à Diriger des Recherches, Université Pierre & Marie Curie, 107 pp. 2009).

    For example, Dufresne reassessed the calculation published in 1896 by Svante Arrhenius on the 5°C warming linked to atmospheric CO2 doubling (compatible with the latest range of model climate sensitivity compiled by the IPCC). To his surprise, Dufresne showed that this widely quoted value is the result of luck. This is due to cancelling of large biases linked to limitations in the absorption data on CO2 and H2O available to Arrhenius and to his use of a one-layer greenhouse model.

    The aim of Dufresne was of course not to alter the fame of Arrhenius (Dufresne even showed that the famous chemist was the first to introduce several ingredients in the greenhouse calculation). The main value of Dufresne’s work is to illustrate that it is (very unfortunately) not possible to make a “back of the envelope” calculation of the CO2 effect by treating the atmosphere as a single layer (reminiscent to the RC post about Angström written by Ray Pierrehumbert). This problem is known to specialists but not by the public and not even by scientists, specialized on other subfields of physics or chemistry, when they try to reinvent the wheel to make their own mind about the greenhouse problem. The 5°C value calculated by Arrhenius in 1896 provides the false impression that such a calculation is possible and that climate modelers did not make any progress over a century despite their use of more and more complex GCMs.

    Jean-Louis Dufresne did also a nice job in checking the robustness of the work performed by other pioneers. Unexpectedly, he showed that Claude Pouillet was correct in his estimation of the solar constant (1228 W/m2 published in 1838), but that his temperature of the Sun was wrong only because of his use of a low-temp approximation of the Stefan-Boltzmann law (empirical law by Dulong & Petit, mainly used in metallurgy). Dufresne corrected the French page of Wikipedia on Pouillet ( ). Unfortunately the English pages are still erroneous when they state “The lower value of 1800 °C was determined by Claude Servais Mathias Pouillet (1790-1868) in 1838 using the Dulong-Petit law. Pouilett (sic) also took just half the value of the Sun’s correct energy flux” ( ).

    Later, Samuel Langley determined the solar output at different wavelengths, but he severely overestimated the total output. It took more than a century to go back to the value measured by Pouillet (without anyone acknowledging or even knowing it). Putting aside my natural chauvinism, this is a lesson for all scientists that a brilliant and influential colleague can slow down a bit his own field if he is too dominant (and even if he did not intend to do so).

    Edouard Bard

    [Response: Bonjour Edouard! I can heartily recommend Jean-Louis' these. It's really outstanding. To help make it more accessible to non-Francophones, David Archer and I have included a discussion of some of Jean-Louis' conclusions regarding Arrhenius in our forthcoming book, "The Warming Papers." I have not independently verified the claims regarding the implications of the index of refraction of salt, but it is clear that Arrhenius used a linear extrapolation which seems inconsistent with modern data. Jean-Louis' conclusions seem to me to hang together. In addition, for the book I independently wrote an Arrhenius one-layer model using modern accurate spectroscopy, using a somewhat different approach to the calculation. My numbers aren't identical to the ones in the these, but they do confirm the general conclusion that if Arrhenius had used the one layer model with correct spectroscopy, he would have arrived at an erroneously low value of warming, owing to spurious masking of CO2 by water vapor opacity. --raypierre]

  20. 20

    Re 19: Link to a pdf version of Jean-Louis Dufresne’s thesis.

  21. 21
    Completely Fed Up says:

    “One of them is screwing up on the PR.”

    Uh, the PR is blown because Faux News is a rightwingnut haven. And that can’t be fixed without closing that slagheap down.

    Have a look at the number of people who are STILL saying Obama’s heath care will kill pensioners.

    It can’t be undone because those EXTREMELY NOISY people do NOT live in the real world. They live in the sheltered world inside their heads where it’s ALL a communist conspiracy.

  22. 22
    Lamont says:

    #16: lindzen used out-of-date ERBS data. corrected data (which existed prior to lindzen publishing) does not show the effect in his paper.

    [Response: Not clear this is quite true for the published paper. Can you provide a cite? - gavin]

  23. 23
    Hank Roberts says:

    Bean links to a copy of Lindzen and Choi at Spencer’s website, says it’s “hard data” — but appears not to have actually read Spencer, who pointed out major problems with it. Bean, did you repost something from somewhere else, or did you actually read Spencer’s website about this paper?

    I think I’ll trust Spencer’s opinion for now.

    Bean, if you got your opinion second hand from some other website–don’t rely on some guy on a blog and trust their opinion (nor on the WSJ for that matter). Spencer put the paper up for discussion, and discussed it. Worth reading.

  24. 24
    Mats Frick says:

    Hello everyone,

    The initial take on the psychology of foxes and hedgehogs was a bit on the shallow side. But don’t despair, here’s a guy who has devoted a career to that particular dichotomy: Philip Tetlock

    You may also want to check out his book.

    Keep up the good work

  25. 25
    TRY says:

    Two things – if you give 5 people a problem to solve, and they all come up with a similar answer, but each of them use assumptions and methods that are demonstrably incorrect – I personally would not treat this as evidence for the accuracy of the answer, but evidence that they knew the answer beforehand.

    I’m a contrarian by nature, and some of the comments directed at me here have been ‘nasty’ and ‘patronizing’ so it’s definitely made me more of a contrarian on this issue. That said, my point above stands, I think – and I doubt that Gavin would claim these historical numbers should be treated as evidence.

    My more general question, and related to my assumption that measuring and analyzing first-order effects is the best way to approach this: how is a tree or a glacier different than a weather station collecting daily data, in terms of assessing the impact of CO2?

    Given the additional impacts of wind/particulates/precipitation/etc on glaciers, tree-rings, and so on, as well as their responses to local temperature. How is a glacial pullback anything more than a record of temperature increase in a specific location, much as you might get from a thermometer (ignoring particulate issues for the sake of discussion)? Genuine question – and a part of my ongoing emphasis on first-degree impact data measurement and analysis.

  26. 26
    Doug Bostrom says:

    Bean says: 4 January 2010 at 2:31 PM

    Wow, that did not take long. Here’s a thread about mainstream science and the developmental track it’s taken for the past 50 years, and straight off it’s swerved into touting an outlier prediction, a speculation given special permission to pass by the rigorous scrutiny accorded to mainstream science by contrarians.

    “Hard data stating global warming will be less than one-sixth than that predicted.”

    Hold on a minute. Where’s the confirmation of that prediction? Surely there’s more to offer than a mere calculation? After all, calculations are dismissed as insufficient if they’re part of the mainstream integrated model of AGW. Where’s the data?

  27. 27
    Josh Cryer says:

    Such a great writeup, thanks for sharing this history Gaven. And also, thanks to Andy for that extra bit of info. I’m going to try to see if UCS has the journal in question in the library, next time I go, would be really cool to see the exchange that is being discussed.

  28. 28

    Re #7 Ike Solem,

    So if Plass was working on detecting targets with heat seaking missiles, he probably noted that a certain amount of CO2 in the path of propagation of the radiating wave from the target heat source to the heat seaking missile would actually attenuate that wave sufficiently that the term “saturation” would apply. I surmise Lockheed would have fired him for wasting his time on a heat transfer problem that operates more slowly such that it is related not at all to the near instantaneous hot target detection problem.

    I see it as quite important that the problem was clarified, I guess by Plass, and we now understand that that there are what I would call secondary processes that are the heating and reradiating that arise following the initial attenuating effect.

    If I see this correctly, it might be ok to just say he added more understanding rather than “debunking” previous thinking.

  29. 29
    Doug Bostrom says:

    “How is a glacial pullback anything more than a record of temperature increase in a specific location, much as you might get from a thermometer (ignoring particulate issues for the sake of discussion)? Genuine question – and a part of my ongoing emphasis on first-degree impact data measurement and analysis.”

    When it’s more than one glacier, in diverse locations?

  30. 30

    Kevin Mckinney wrote: It seems that Plass’s case is parallel to Arrhenius’s in that both were right about the big picture, both had predictions that turned out to be correct, but both had some luck in terms of “error cancellation.”

    Yes, Arrhenius’s work seems to be slowly becoming better known, much the least, because he wrote in a non-English language. He has been mentioned more frequently in some more recent journal articles:

    From the Peer-reviewed Ambio journal (2001): “How did Arrhenius conduct his calculations into the “hothouse” effect of CO2? They were, says Gustaf Arrhenius, “done on the same basis as they are done now, only without the aid of digital computers.” He divided the world into small squares and calculated for each one the warming effect, taking into account local conditions and their likely feedbacks. He knew the impact of features such as clouds in his calculations, and that “refinement of these made all the difference between the greenhouse effect becoming positive or negative,” says Gustaf Arrhenius. His devotion to such detail, he says, explains why “his results came close to what dozens of people spend hundreds of hours of computer-time on today.” He concluded that, globally, a doubling of CO2 levels would raise temperatures by 5–6°C. And a halving would reduce temperatures by a similar amount—enough to bring on another Ice Age.”
    AmBio,Volume 30, Issue 3 (May 2001)

    “…the greenhouse
    effect, whereby the presence of an
    atmosphere acts to increase a planet’s surface
    temperature. Written in 1827, nearly three quarters
    of a century before science advanced
    to the point where Arrhenius could quantify
    the phenomenon…” Pierrehumbert, Nature 2004

    “Svante Arrhenius, who was first to predict global warming as a consequence of using fossil fuels.” Bard C. R. Geoscience 336 (2004) 603–638 2004

    Svante Arrhrenius-1897- Model, grids, predicted more warming at poles, …AMBIO peer-reviewed journal, 1997, vol. 26, no. 1. (Published by Royal Swedish Academy of Sciences) ( . A Journal of the Human Environment ).
    J Uppenbrink – Science, 1996
    H von Storch, N Stehr – NATURE, 2000
    K Hasselmann – Nature, 1997
    RE Benestad – Climatic Change, 2003
    V Ramanathan – Science, 1988

  31. 31
    Thomas says:

    Well, to answer TRY, about glacier or tree ring proxies. Obviously temperature isn’t the only thing affecting either system. Glaciers will also respond to changes in precipitation and to changes in the amount of shortwave radiation (which could be affected by cloudiness). Tree growth depends upon other factors than just temperature as well, and you’d probably have to be a biologist to sort it out. Nevertheless we do have other proxies, such as the isotopic concentrations seen in ice, that can be used to disambiguate the temperature from the other factors. Climate reconstructions do not rely upon single proxies, but upon multiple independent proxies which need to be looked at together so that a consistient picture can be built up. And Doug’s point, that these proxies are compared to other similar ones in many different locations is valid as well.

  32. 32

    Re 19.
    “These d’Habilitation à Diriger des Recherches, Université Pierre & Marie Curie, 107 pp. 2009).” … Dufresne showed that this widely quoted value is the result of luck. This is due to cancelling of large biases linked to limitations in the absorption data on CO2 and H2O available to Arrhenius and to his use of a one-layer greenhouse model.

    Is this the place to state this yet?

    I thought in 1906 Arrhenius adjusted the value downwards to 1.6 °C (including with a water vapour feedback of 2.1 °C).”Ueber den Einfluss des Atmosphärischen Kohlensäurengehalts auf die Temperatur der Erdoberfläche, in the Proceedings of the Royal Swedish Academy of Science, Stockholm 1896, Volume 22, I N. 1, pages 1–101…

    I certainly don’t mean any disrespect at all…but how do you know there are no problems with your numbers and that all angles have been considered…(and they could be dead on right)…have your figures been published in a major journal or convention for verification as all accepted scientific studies are? I appologize if they have.

    As Gavin has said: “Peer-review: necessary, but not sufficient!”

  33. 33
    ccpo says:

    I’m a contrarian by nature

    That’s not contrarianism, it’s obstinance. There is nothing in our “nature” that can make us contrarian.

    “and some of the comments directed at me here have been ‘nasty’ and ‘patronizing’ so it’s definitely made me more of a contrarian on this issue.”

    People insult you (or maybe just point out reality), so you dismiss an entire field of science?

    Yes, I think you should post more.


    [Response: Actually, I'm going to defend him on this one. Some people do have a contrary nature - especially scientists - and in fact including me. It comes down to initially adopting a 'show me' stance when you see new ideas and trying to burrow down into the assumptions that might underlie it. In small does it comes in quite handy. However, this has to be tempered with an open mind that allows you to be persuaded by new information. Contrarianism combined with obstinacy and a dash (or more) of political advocacy and you end up with Lindzen or worse. - gavin]

  34. 34
    Lamont says:

    Gavin — while Lindzen references Wong, 2006 in a couple places, isn’t the dataset in Lindzen just the ERBE edition 3 dataset without the revision to correct the instrument drift that was found in Wong, 2006 (and is referred to in Wong, 2006 as ERBE edition 3 revision 1?)

  35. 35
    Connor says:

    An interesting read on the philosophy of science and Pessimistic Meta-Induction:

    “Firstly, it’s true: our current scientific theories are almost certainly wrong. If you look through history, all of our most successful, most beautiful and most explanatory theories have been wrong. Based on that evidence, we’d be mad to think our current theories are right. Philosophers of science call this argument the Pessimistic Meta-Induction. (Comedian Dara O’Briain makes some funny jokes about misuses of this form of reasoning.)

    The question is, what follows from the Pessimistic Meta-Induction? If our theories are false, should we ignore them?

    The answer is a clear “No”. If you look through the history of science, successful scientific theories that garnered consensus yielded good advice. Although Newtonian mechanics is wrong, it still yields the right advice for any situation you’re likely to come across.

    Newtonian mechanics will tell you that if you want your car to go faster, you should make it less heavy. Just because the theory behind that advice turned out to be wrong, doesn’t mean the advice was wrong.

    Similarly, even if climate science turns out to be inaccurate in some way, the advice it is giving us is clear. Cutting emissions is essential for stopping global warming.”

  36. 36
    sidd says:

    Mr. CM idly wonders on the 4th of January, 2010 at 10:36 AM:
    “…is there some way to cultivate a knack for making one’s errors cancel out…”

    i suppose one could study Drude’s schooling

  37. 37
    Edward Greisch says:

    The fairy tale of the porcupine and the fox is one I missed as a child. Having read ~ 200 headlines, I still haven’t found the right one in Google.

    But the real message is that, ever since 1897, scientists have been refining their calculations of the climate sensitivity? A large enough number of people have tried their hands at it. We are getting close to the correct number. Conspiracy over a century is impossible. This is real. The story of Gilbert Plass and all those other people is to inform the world that global warming is real and serious.

    And the real problem is that, for Homo Sap to survive, democracy isn’t really the right form of government. Politicians have to take dictation from scientists. Since the world doesn’t work that way, scientists don’t make good politicians or dictators, there will be a dark age of death and chaos.

    The carbon dioxide theory of Gilbert Plass needs to be read by Robert Reich on his radio hour on PBS, as soon as he gets a dedicated daily hour on PBS. Prior to that, the story of the porcupine and the fox needs to be aired on Sesame Street.

  38. 38
    Geoff Wexler says:

    Very interesting discussion. Does your description of the 1956 article in the American Scientist as ‘pop piece’ include its account of the greenhouse effect by analogy with a glass greenhouse without reference to the role of the temperature distribution?

    I wonder if Plass knew about the negative result obtained by R.W. Wood (now well known) with a couple of blackened cardboard boxes one covered with glass and the other with rock salt ,which transmits infrared. Plass would have understood why the glass one showed so little additional radiative warming. This was because the temperature of the lid which depends upon a self consistent treatment of convection and radiation, was too close to that of the floor and walls of the box. So the outward radiation from the glass would not have been substantially reduced.

    He might perhaps have been able to suggest an alternative experiment with a skyscraper greenhouse for which the analogy might have been better. Too much for a pop piece?

  39. 39
  40. 40
    Alan of Oz says:

    Can I buy a preview button? Last post was in response to #35.

  41. 41
    Damien says:

    Ike Solem@7,

    On the Australian Floods, I thought they were due to the recent break-up of cyclones over the Northern Territory. For example, this news article

    While we’re in this part of the world, the government is using the BoM’s announcement that 2009 was the second hottest year on record to hit the opposition over the head. Whether it has any traction remains to be seen – it is an election year, after all.

  42. 42
    Schmert says:

    “a concept that wasn’t fully worked out until Revelle and Suess’s paper in 1957″

    So there really was a Dr. Seuss ?

    [Response: Actually, Revelle and Suess get far too much credit for this important bit of ocean chemistry. It is clear even from the references in Revelle and Suess that the basic buffer chemistry was known decades earlier. In fact, there are even indications from exchanges between Arrhenius and Hogbom that Arrhenius knew about it, and knew it would limit ocean CO2 uptake. The credit should go to whoever first drew the correct conclusions regarding anthropogenic CO2 increase, and here Revelle and Suess messed things up and in fact drew a completely incorrect conclusion. Credit for getting the so-called "Revelle Buffer Factor" right should really go to a paper by Bolin and Eriksson, published at essentially the same time. All this is made clear, together with reprints of the relevant original papers, in the forthcoming book "The Warming Papers," by Archer and myself, due out this year from Wiley/Blackwell. --raypierre]

  43. 43
    Geoff Wexler says:

    Re #1
    Michael Schlesinger has highlighted the following remark in that quote from the NYT of 1956.

    These cannot absorb much of the heat radiated by the earth after it has been warmed by the sun. If they could the climate would be far colder than it is today,…

    ['These' refers to oxygen and nitrogen]

    Perhaps one day historians of science will examine scientific journalism as carefully as Gavin is analysing early research?

  44. 44
    Geoff Wexler says:

    Re: my #39.

    To test Plass’s analogy between CO2 and glass greenhouses (continued).
    Instead of the thought experiment of scaling up a glass greenhouse in all directions, perhaps it might be possible to construct a calorimeter with a heated floor or cooled roof? I’m sure that Plass’s analogy has some theoretical validity even if it is inapplicable to glass greenhouses under most realistic conditions.

  45. 45
    John E. Pearson says:

    Andy: (13) Are you sure that it was Plass who built the laser? I was always under the impression that he was strictly a theoretician. A&M had both low temperature and atomic and molecular experimental groups either of which might have built a helium cooled laser but as far as I knew Plass was not in them. There was a pretty strong planetary atmospheres group consisting of Plass, George Kattawar, and several senior scientists who were not faculty: Andy Young, Louise Young, and Ronald Schorn. There might’ve been others. I’m recalling this from pure memory and jeez, I haven’t thought about these folks for decades. I think I’ve got the names right.

  46. 46
    Hank Roberts says:

    So, Bean, work with us other readers here, we’re mostly amateur readers like you trying to learn how this stuff works. Where’d you come across mention of Lindzen and Choi? Who did you consider a reliable source for the beliefs you posted above? How do you decide who to trust on this sort of thing?

  47. 47
    Hank Roberts says:

    > 35 Connor
    > 40 Geoff

    Good links and reminders, thank you both for pointers worth reading.
    Robert Grumbine has made a similar point at his blog a while back (though the search tool doesn’t handle arithmetic well, couldn’t find it again).

    He was reminding some of us not to leap all over new posters with all four feet. He pointed out that while some people with doubts about climate science seem to believe, as someone said dismissively, that 2+2=5, this is much closer to correct than believing that 2+2= some much larger number.

  48. 48
    Completely Fed Up says:

    Geoff, that cooling/warming surface would break up for the exact same reason as a tiny model boat on a small tank of water doesn’t look real: it’s too small. The Physics knows the difference and in this particular case, you’d have convection relatively huge.

    There’s no substitute for size if you’re going to model something like this in a lab.

  49. 49
    Dean Weichmann, Wisconsin says:

    I am not a climatologist so please be kind to me. I wondered if warming temps and thus higher dew points (moisture carried in the atmosphere) could result in greater snowfall in higher elevations. This in turn resulting in greater deposits at the beginning of glaciers.

    Would Antartica gain more ice?

  50. 50
    Completely Fed Up says:

    “I am not a climatologist so please be kind to me.”

    There’s nothing wrong in not being a climatologist.

    Claiming to be one and asking dumb questions about climate is a different matter…

    “I wondered if warming temps and thus higher dew points (moisture carried in the atmosphere) could result in greater snowfall in higher elevations.”

    It can, but you tend to get dryer air after raining and it would like to rain earlier. Whether this happens is dependent on a lot of things. Some places, yes. Some no.

    “Would Antartica gain more ice?”

    It has been. The central plain of Antarctica is the driest place on earth. It’s too darn cold there for there to be enough water to fall down when it freezes.

    So when it warms up, there’s some more water (if it hasn’t dried out by falling even heavier elsewhere) and it’s still far below freezing.

    So it falls as snow.

    Therefore, despite it being warmer you can get more snow.

    Whether that happens in more variable places (I.e NOT at the pole) depends on what the land is doing and what the weather normally does.

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