By Christopher Monckton of Brenchley
My commentary written for Remote Sensing on the empirical determination of climate sensitivity, published by the splendid Anthony Watts some days ago, has aroused a great deal of interest among his multitudes of readers. It is circulating among climate scientists on both sides of the debate. Several of Anthony’s readers have taken the trouble to make some helpful comments. Since some of these are buried among the usual debates between trolls on how awful I am, and others were kindly communicated privately, I have asked Anthony to allow me, first and foremost, to thank those readers who have been constructive with their comments, and to allow his readers the chance to share the comments I have received.
Joel Shore pointed out that Schwartz, whose paper of 2007 I had cited as finding climate sensitivity to be ~1 K, wrote a second paper in 2008 finding it close to 2 K. Shore assumed I had seen but suppressed the second paper. By now, most of Anthony’s readers will perhaps think less ungenerously of me than that. The new .pdf version of the commentary, available from Anthony’s website (here), omits both Schwartz papers: but they will be included in a fuller version of the argument in due course, along with other papers which use observation and measurement, rather than mere modeling, to determine climate sensitivity.
Professor Michael Asten of Monash University helpfully provided a proper reference in the reviewed literature for Christopher Scotese’s 1999 paper reconstructing mean global surface temperatures from the Cambrian Era to the present. This, too, has been incorporated into the new .pdf.
Professor Asten also supplied a copy of a paper by David Douglass and John Christy, published in that vital outlet for truth Energy & Environment in 2009, and concluding on the basis of recent temperature trends that feedbacks were not likely to be net-positive, implying climate sensitivity ~1 K. I shall certainly be including that paper and several others in the final version of the full-length paper that underlies the commentary published by Anthony. This paper is now in draft and I should be happy to send it to any interested reader who emails monckton@mail.com.
A regular critic, Lucia Liljegren was, as all too often before, eager to attack my calculations – she erred in publishing a denial that I sent her a reference that I can prove she received; and not factually accurate in blogging that “Monckton’s” Planck parameter was “pulled out of a hat” when I had shown her that in my commentary I had accepted the IPCC’s value as correct. She was misleading her readers in not telling them that the “out-of-a-hat” relationship she complains of is one which Kiehl and Trenberth (1997) had assumed, with a small variation (their implicit λ0 is 0.18 rather than the 0.15 I derived from their paper via Kimoto, 2009); and selective in not passing on that I had told her they were wrong to assume that a blackbody relationship between flux and temperature holds at the surface (if it did, as my commentary said, it would imply a climate sensitivity ~1 K).
A troll (commenter on WUWT) said I had “fabricated” the forcing function for CO2. When I pointed out that I had obtained it from Myhre et al. (1998), cited with approval in IPCC (2001, 2007), he whined at being called a troll (so don’t accuse me of “fabricating” stuff, then, particularly when I have taken care to cite multiple sources, none of which you were able to challenge) and dug himself further in by alleging that the IPCC had also “fabricated” the CO2 forcing function. No: the IPCC got it from Myhre et al., who in turn derived it by inter-comparison between three models. I didn’t and don’t warrant that the CO2 forcing function is right: that is above my pay-grade. However, Chris Essex, the lively mathematician who did some of the earliest spectral-line modeling of the CO2 forcing effect, confirms that Myhre and the IPCC are right to state that the function is a logarithmic one. Therefore, until I have evidence that it is wrong, I shall continue to use it in my calculations.
Another troll said – as usual, without providing any evidence – that I had mis-stated the result from process engineering that provides a decisive (and low) upper bound to climate sensitivity. In fact, the result came from a process engineer, Dr. David Evans, who is one of the finest intuitive mathematicians I have met. He spent much of his early career designing and building electrical circuitry and cannot, therefore, fairly be accused of not knowing what he is talking about. Since the resulting fundamental upper limit to climate sensitivity is as low as 1.2 K, I thought readers might be interested to have a fuller account of it, which is very substantially the work of David Evans. It is posted below this note.
Hereward Corley pointed out that the reference to Shaviv (2008) should have been Shaviv (2005). Nir Shaviv – another genius of a mathematician – had originally sent me the paper saying it was from 2008, but the version he sent was an undated pre-publication copy. Mr. Corley also kindly supplied half a dozen further papers that determine climate sensitivity empirically. Most of the papers find it low, and all find it below the IPCC’s estimates. The papers are Chylek & Lohman (2008); Douglass & Knox (2005); Gregory et al. (2002); Hoffert & Covey (1992); Idso (1998); and Loehle & Scafetta (2011).
I should be most grateful if readers would be kind enough to draw my attention to any further papers that determine climate sensitivity by empirical methods rather than by the use of general-circulation models. I don’t mind what answers the papers come to, but I only want those that attempted to reach the answer by measurement, observation, and the application of established theory to the results.
Many thanks again to all of you for your interest and assistance. Too many of the peer-reviewed journals are no longer professional enough or unprejudiced enough to publish anything that questions the new State religion of supposedly catastrophic manmade global warming. Remote Sensing, for instance has still not had the courtesy to acknowledge the commentary I sent. Since the editors of the learned journals seem to have abdicated their role as impartial philosopher-kings, WattsUpWithThat is now the place where (in between the whining and whiffling and waffling of the trolls) true science is done.
The fundamental constraint on climate sensitivity
A fundamental constraint rules out strongly net-positive temperature feedbacks acting to amplify warming triggered by emissions of greenhouse gases, with the startling result that climate sensitivity cannot much exceed 1.2 K.
Sensitivity to doubled CO2 concentration is the product of three parameters (Eq. 1):
- the radiative forcing ΔF2x = 5.35 ln 2 = 3.708 W m–2 at CO2 doubling (Eq. 2), from the function in Myhre et al. (1998) and IPCC (2001, 2007);
- the Planck zero-feedback climate sensitivity parameter λ0 = 0.3125 K W–1 m2 (Eq. 3), equivalent to the first differential of the fundamental equation of radiative transfer in terms of mean emission temperature TE and the corresponding flux FE at the characteristic-emission altitude (CEA, one optical depth down into the atmosphere, where incoming and outgoing fluxes are identical), augmented by approximately one-sixth to allow for latitudinal variation (IPCC, 2007, p. 631 fn.);
- the overall feedback gain factor G (Eq. 4), equivalent, where feedbacks are assumed linear as here, to (1 – g)–1, where the feedback loop gain g is the product of λ0 and the sum f of all unamplified temperature feedbacks f1, f2, … fn, such that the final or post-feedback climate sensitivity parameter λ is the product of λ0 and G.
The values of the first two of the three parameters whose product is climate sensitivity are known (Eqs. 2-3). The general-circulation models, following pioneering authors such as Hansen (1984), assume that the feedbacks acting upon the climate object are strongly net-positive (G 1: the IPCC’s implicit central estimate is G = 2.81). In practice, however, neither individual temperature feedbacks nor their sum can be directly measured; nor can feedbacks be readily distinguished from forcings (Spencer & Braswell, 2010, 2011; but see Dessler, 2010, 2011).
Temperature feedbacks – in effect, forcings that occur because a temperature change has triggered them – are the greatest of the many uncertainties that complicate the determination of climate sensitivity. The methodology that the models adopt was first considered in detail by Bode (1945) and is encapsulated at its simplest, assuming all feedbacks are linear, in Eq. (4). Models attempt to determine the value of each distinct positive (temperature-amplifying) and negative (temperature-attenuating) feedback in Watts per square meter per Kelvin of original warming. The feedbacks f1, f2, … fn are then summed and mutually amplified (Eq. 4).
Fig. 1 schematizes the feedback loop:
Figure 1. A forcing ΔF is input (top left) by multiplication to the final sensitivity parameter λ = λ0G, where g = λ0f = 0.645 is the IPCC’s implicit central estimate of the loop gain and G = (1 – g)–1 = 2.813 [not shown] is the overall gain factor: i.e., the factor by which the temperature change T0 = ΔF λ0 triggered by the original forcing is multiplied to yield the output final climate sensitivity ΔT = ΔF λ = ΔF λ0 G (top right). To generate λ = λ0 G, the feedbacks f1, f2, … fn, summing to f, are mutually amplified via Eq. (4). Stated values of λ0, f, g, G, and λare those implicit in the IPCC’s central estimate ΔT2x = 3.26 K (2007, p. 798, Box 10.2) in response to ΔF2x = 5.35 ln 2 = 3.708 W m–2. Values for individual feedbacks f1–f4 are taken from Soden & Held (2006). (Author’s diagram from a drawing by Dr. David Evans).
The modelers’ attempts to identify and aggregate individual temperature feedbacks, while understandable, do not overcome the difficulties in distinguishing feedbacks from forcings or even from each other, or in determining the effect of overlaps between them. The methodology’s chief drawback, however, is that in concentrating on individual rather than aggregate feedbacks it overlooks a fundamental physical constraint on the magnitude of the feedback loop gain g in Eq. (4).
Paleoclimate studies indicate that in the past billion years the Earth’s absolute global mean surface temperature has not varied by more than 3% (~8 K) either side of the 750-million-year mean (Fig. 2):
Figure 2. Global mean surface temperature over the past 750 million years, reconstructed by Scotese (1999), showing variations not exceeding 8 K (<3%) either side of the 291 K (18 °C) mean.
Consistent with Scotese’s result, Zachos et al. (2001), reviewing detailed evidence from deep-sea sediment cores, concluded that in the past 65 Ma the greatest departure from the long-run mean was an increase of 8 K at the Poles, and less elsewhere, during the late Paleocene thermal maximum 55 Ma BP.
While even a 3% variation either side of the long-run mean causes ice ages at one era and hothouse conditions at another, in absolute terms the temperature homeostasis of the climate object is formidable. At no point in the geologically recent history of the planet has a runaway warming occurred. The Earth’s temperature stability raises the question what is the maximum feedback loop gain consistent with the long-term maintenance of stability in an object upon which feedbacks operate.
The IPCC’s method of determining temperature feedbacks is explicitly founded on the feedback-amplification equation (Eq. 4, and see Hansen, 1984) discussed by Bode (1945) in connection with the prevention of feedback-induced failure in electronic circuits. A discussion of the methods adopted by process engineers to ensure that feedbacks are prevented in electronic circuits will, therefore, be relevant to a discussion of the role of feedbacks acting upon the climate object.
In the construction of electronic circuits, where one of the best-known instances of runaway feedback is the howling shriek when a microphone is placed too close to the loudspeaker to which it is connected, electronic engineers take considerable care to avoid positive feedback altogether, unless they wish to induce a deliberate instability or oscillation by compelling the loop gain to exceed unity, the singularity in Eq. (4), at which point the magnitude of the loop gain becomes undefined.
In electronic circuits for consumer goods, the values of components typically vary by up to 10% from specification owing to the vagaries of raw materials, manufacture, and assembly. Values may vary further over their lifetime from age and deterioration. Therefore engineers ensure long-term stability by designing in a negative feedback to ensure that vital circuit parameters stay close to the desired values.
Negative feedbacks were first posited by Harold S. Black in 1927 in New York, when he was looking for a way to cancel distortion in telephone relays. Roe (2009) writes:
“He describes a sudden flash of inspiration while on his commute into Manhattan on the Lackawanna Ferry. The original copy of the page of the New York Times on which he scribbled down the details of his brainwave a few days later still has pride of place at the Bell Labs Museum, where it is regarded with great reverence.”
One circuit parameter of great importance is the (closed) feedback loop gain inside any amplifier, which must be held at less than unity under all circumstances to avoid runaway positive feedback (g ≥ 1). The loop gain typically depends on the values of at least half a dozen components, and the actual value of each component may randomly vary. To ensure stability the design value of the feedback loop gain must be held one or two orders of magnitude below unity: g <0.1, or preferably <0.01.
Now consider the common view of the climate system as an engine for converting forcings to temperature changes – an object on which feedbacks act as in Fig. 1. The values of the parameters that determine the (closed) loop gain, as in an electronic circuit, are subject to vagaries. As the Earth evolves, continents drift, sometimes occupying polar or tropical positions, sometimes allowing important ocean currents to pass and sometimes impeding or diverting them; vegetation comes and goes, altering the reflective, radiative, and evaporative characteristics of the land and the properties of the coupled atmosphere-ocean interface; volcanoes occasionally fill the atmosphere with smoke, sulfur, or CO2; asteroids strike; orbital characteristics change slowly but radically in accordance with the Milankovich cycles; and atmospheric concentrations of the greenhouse species, vary greatly.
In the Neoproterozoic, 750 Ma BP, CO2 concentration (today <0.04%) was ~30%: otherwise the ocean’s magnesium ions could not have united with the abundance of calcium ions and with CO2 itself to precipitate the dolomitic rocks laid down in that era. Yet mile-high glaciers came and went twice at sea level at the equator.
As in the electronic circuit, so in the climate object, the values of numerous key components contributing to the loop gain change radically over time. Yet for at least 2 Ga the Earth appears never to have endured the runaway greenhouse warming that would have occurred if the loop gain had reached unity. Therefore, the loop gain in the climate object cannot be close to unity, for otherwise random mutation of the feedback-relevant parameters of vital climate components over time would surely by now have driven it to unity. It is near-certain, therefore, that the value of the climatic feedback loop gain g today must be very much closer to 0 than to 1.
A loop gain of 0.1, then, is in practice the upper bound for very-long-term climate stability. Yet the loop gain values implicit in the IPCC’s global-warming projections of 3.26[2, 4.5] K warming in response to a CO2 doubling are well above this maximum, at 0.64[0.42, 0.74] (Eq. 8). Values such as these are far too close to the steeply-rising segment of the climate-sensitivity curve (Fig. 3) to have allowed the climate to remain temperature-stable for hundreds of millions of years, as Zachos (2001) and Scotese (1999) have reported.
Figure 3. The climate-sensitivity curve at loop gains –1.0 ≤ g < +1.0. The narrow shaded zone at bottom left indicates that climate sensitivity is stable at 0.5-1.3 K per CO2 doubling for loop gains –1.0 ≤ g ≤ +0.1, equivalent to overall feedback gain factors 0.5 ≤ G ≤ 1.1. However, climate sensitivities on the IPCC’s interval [2.0, 4.5] K (shaded zone at right) imply loop gains on the interval (+0.4, +0.8), well above the maximum loop gain that could obtain in a long-term-stable object such as the climate. At a loop gain of unity, the singularity in the feedback-amplification equation (Eq. 4), runaway feedback would occur. If the loop gain in the climate object were >0.1, then at any time conditions sufficient to push the loop gain towards unity might occur, but (see Fig. 2) have not occurred in close to a billion years (author’s figure based on diagrams in Roe, 2009; Paltridge, 2009; and Lindzen, 2011).
Fig. 3 shows the climate-sensitivity curve for loop gains g on the interval [–1, 1). It is precisely because the IPCC’s implicit interval of feedback loop gains so closely approaches unity, which is the singularity in the feedback-amplification equation (Eq. 4), that attempts to determine climate sensitivity on the basis that feedbacks are strongly net-positive can generate very high (but physically unrealistic) climate sensitivities, such as the >10 K that Murphy et al. (2009) say they cannot rule out.
If, however, the loop gain in the climate object is no greater than the theoretical maximum value g = 0.1, then, by Eq. (4), the corresponding overall feedback gain factor G is 1.11, and, by Eq. (1), climate sensitivity in response to a CO2 doubling cannot much exceed 1.2 K. No surprise, then, that the dozen or more empirical methods of deriving climate sensitivity that I included in my commentary cohered at just 1 K. If that is indeed the answer to the climate sensitivity question, it is also a mortal blow to climate extremists worldwide – but good news for everyone else.
References
Bode, H.W., 1945, Network analysis and feedback amplifier design, Van Nostrand, New York, USA, 551 pp.
Chylek, P., and U. Lohman, 2008, Aerosol radiative forcing and climate sensitivity deduced from the last glacial maximum to Holocene transition, Geophys. Res. Lett. 35, doi:10.1029/2007GL032759.
Dessler, A.E., 2010, A determination of the cloud feedback from climate variations over the past decade, Science 220, 1523-1527.
Dessler, A.E., 2011, Cloud Variations and the Earth’s Energy Budget, Geophys. Res. Lett. [in press].
Douglass, D.H., and R.S. Knox, 2005, Climate forcing by the volcanic eruption of Mount Pinatubo, Geophys. Res. Lett. 32, doi:10.1029/2004GL022119.
Douglass, D.H., and J.R. Christy, 2009, Limits on CO2 climate forcing from recent temperature data of Earth, Energy & Environment 20:1-2, 177-189.
Gregory, J.M., R.J. Stouffer, S.C. Raper, P.A. Stott, and N.A. Rayner, 2002, An observationally-based estimate of the climate sensitivity, J. Clim. 15, 3117-3121.
Hansen, J., A., Lacis, D. Rind, G. Russell, P. Stone, I. Fung, R. Ruedy, and J. Lerner, 1984, Climate sensitivity: analysis of feedback mechanisms, Meteorological Monographs 29, 130-163.
Hoffert, M.I., and C. Covey, 1992, Deriving global climate sensitivity from paloeclimate reconstructions, Nature 360, 573-576.
Idso, S.B., 1998, CO2-induced global warming: a skeptic’s view of potential climate change, Clim. Res. 10, 69-82.
IPCC, 2001, Climate Change 2001: The Scientific Basis. Contribution of Working Group I to the Third Assessment Report of the Intergovernmental Panel on Climate Change [Houghton, J.T., Y. Ding, D.J. Griggs, M. Noguer, P.J. van der Linden, X. Dai, K. Maskell and C.A. Johnson (eds.)]. Cambridge University Press, Cambridge, United Kingdom, and New York, NY, USA.
IPCC, 2007, Climate Change 2007: the Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, 2007 [Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Avery, M. Tignor and H.L. Miller (eds.)], Cambridge University Press, Cambridge, United Kingdom, and New York, NY, USA.
Kimoto, K., 2009, On the confusion of Planck feedback parameters, Energy & Environment 20:7, 1057-1066.
Lindzen, R.S., 2011, Lecture to the American Chemical Society, Aug. 28.
Loehle, C., and Scafetta, N., 2011, Climate change attribution using empirical decomposition of climatic data, Open Atmos. Sci. J. 5, 74-86.
Murphy, D. M., S. Solomon, R. W. Portmann, K. H. Rosenlof, P. M. Forster, and T. Wong 2009, An observationally-based energy balance for the Earth since 1950, J. Geophys. Res., 114, D17107, doi:10.1029/2009JD012105.
Myhre, G., E. J. Highwood, K. P. Shine, and F. Stordal, 1998, New estimates of radiative forcing due to well mixed greenhouse gases, Geophys. Res. Lett. 25:14, 2715–2718, doi:10.1029/98GL01908.
Paltridge, G., 2009, The Climate Caper, Connor Court, Sydney, Australia, 110 pp.
Roe, G., 2009, Feedbacks, Timescales, and Seeing Red, Ann. Rev. Earth. Planet. Sci. 37, 93-115.
Schwartz, S.E., 2007, Heat capacity, time constant, and sensitivity of Earth’s climate system, J. Geophys. Res. 112, D24So5, doi:10.1029/2007JD008746.
Schwartz, S.E., 2008, Reply to comments by G. Foster et al., R. Knutti et al., and N. Scafetta on “Heat Capacity, time constant, and sensitivity of Earth’s climate system”, J. Geophys. Res. 113, D15015, doi: 10.1029/2008JD009872.
Scotese, C.R., A.J. Boucot, and W.S. McKerrow, 1999, Gondwanan paleogeography and paleoclimatology, J. African Earth Sci. 28:1, 99-114.
Shaviv, N., 2005, On climate response to changes in the cosmic-ray flux and radiative budget, J. Geophys. Res., doi:10.1029.
Soden, B.J., and I.M. Held, 2006, An assessment of climate feedbacks in coupled ocean-atmosphere models. J. Clim. 19, 3354–3360.
Spencer, R.W., and W.D. Braswell, 2010, On the diagnosis of radiative feedback in the presence of unknown radiative forcing, J. Geophys. Res, 115, D16109.
Spencer, R.W., and W.D. Braswell, 2011, On the misdiagnosis of surface temperature feedbacks from variations in Earth’s radiant-energy balance, Remote Sensing 3, 1603-1613, doi:10.3390/rs3081603.
Zachos, J., M. Pagani, L. Sloan, E. Thomas, and K. Billups, 2001, Trends, Rhythms and Aberrations in Global Climate 65 Ma to Present, Science 292, 686-693.
Dang! RS not RSS. My fingers just want to type the second S!
John– Obviously, anything lengthy involving entering equations in LaTex, including figures etc. I will post at my blog. I have a moderate traffic blog and I wouldn’t dream of burdening Anthony with formatting my equations or having to moderate comments for my sake.
No doubt, should Monckton wish to write a long post, he will post from here. That suits me. I’ll see the incoming ping.
For some technical aspects, my blog has advantages. Comments here don’t have a preview or edit feature; mine do. (This is because I self host and Anthony uses WordPress which doesn’t support that feature.)
I always see when Anthony pings me and he sees when I ping him. This has worked for a long time.
….and despite my challenge, the thread remains locked in a titfortat ad naseum debate about who said what and when a and where and in which context…but my challenge goes unanswered. So I will repeat it:
o According to the IPCC, “doubling” of CO2 = 3.7w/m2 = ~ +1 degrees C “average”
o The reference to “doubling” is defacto acceptance of CO2′s direct effects being logarithmic, and no IPCC reference I’ve seen claims otherwise
o Initial conditions per the IPCC are 280 PPM in the atmosphere. (The IPCC quotes 278 PPM, for simplicity I’ve used 280 PPM). They fix the initial date as about 1920, the beginning of the industrial age.
o The current concentration of CO2 is close to 400 PPM, with the increase over the last ~90 years being about 120 PPM.
o Keeping in mind that CO2 is logarithmic, and lab results can easily quantify that fact, we can arrive at the following. (Gory math not shown for brevity, all values approximate for simplicity):
280 + 120 = 400 PPM
Direct warming vs 280 PPM is ~ 0.6 C
400 +120 = 520 PPM
Direct warming vs 400 PPM is ~ 0.3 C
520 + 120 = 640 PPM
Direct warming vs 520 PPM is ~ 0.15 C
640 + 120 = 760 PPM
Direct warming vs 640 PPM is ~ 0.08 C
640 + 120 = 880 PPM
Direct warming vs 760 PPM is ~ 0.04 C
Can anyone propose a feedback mechanism that would result in LINEAR (let alone exponential) increases in average temperature in response to increasing levels of CO2?
Lucia’s comments, along with the cacophony of like minded sneering and snide found at The Blackboard can do little to endear Lord Monckton, nor to lead to a civil and meaningful exchange.
Sadly, Lucia’s blog, which I now rarely visit, regularly supports caustic posts directed towards WUWT and contributors to the site. There seems little or no effort expended into maintaining civility nor attempting to moderate the “unpleasant” side.
Perhaps if Lucia devoted a little more time to being civil and promoting civility at her blog, she might see others reciprocate. With things as they are, and bearing in mind the rude and arrogant tone of her review of Lord Monckton’s work, I see little cause for complaint if she is treated with less civility than she would like.
IMHO, Lord Monckton has been more than polite enough to those who try to ridicule and insult him rather than properly counter his arguments. Don’t throw the toys out of the pram if he hits back when attacked, however much you think you’ve disguised it!
John–
Perhaps you think my recent response to Monckton is a was a complaint about lack of civility:
It was not. It is a request that he back up what he claims about what I told my readers at my blog by finding quotes where I actually say those things. Presumably, if I said those things, he can locate those quotes.
I also don’t think I or my co-authors have posted caustic posts directed toward WUWT and contributors toward this site. It is true that some blog visitors (for example Neven) make caustic comments about WUWT– but some visitors to WUWT make caustic remarks right here at WUWT. Anthony tends to moderate lightly compared to moderators at RC and permits some of this. My moderation is lighter still. So yes, you’ll find discussion of WUWT at my blog with some people criticizing it, some people supporting it and some remaining neutral.
This thread reminds of the words of the old philosopher
“It is impossible to speak in such a way that you cannot be misunderstood.”
davidmhoffer says:
Unfortunately, david, you did not do the “gory math” correctly. If you are correct and the no-feedback temperature increase going from 280 to 400ppm is 0.6 C (which is not exactly but close enough to being correct, particularly since the IPCC puts the no-feedback sensitivity at a little over 1 C), then these are the correct values for the subsequent increments:
400 to 520 ppm: 0.44 C
520 to 640 ppm: 0.35 C
640 to 760 ppm: 0.29 C
760 to 880 ppm: 0.25 C
So, in fact the decrease with each added increment is not nearly so fast as you think! (You seem to be under the misapprehension that a logarithmic function says each time you add an increment, you get half what you got with the previous addition. That is not what it says. What it says is that what you get is proportional to the FRACTIONAL increase in the CO2 concentration rather than the absolute increase.)
Joel Shore;
Well, at last a response from someone.
Fine Joel, let’s use your numbers. Can you propose a feedback mechanism that would result in accelerating or even linear temperature increases driven by the numbers you propose?
Joel Shore;
Your math is wrong.
1 degree PER CO2 DOUBLING.
280 x 2 = 560 = 1 degree
560 X 2 = 1,120 = 2 degrees (compared to 280)
You’ve got 1.33 degrees just going from 400 to 880!
lucia was right to question this particular part of Monckton’s paper.
I don’t think the math works here. There is a paper backing it up but it misses part of the equation and it also uses a shortcut (which is often a problem in clmate science and even in the central philosophy of global warming at 3.0C per doubling which uses shortcuts which is not how the real energy/temperature/atmosphere works.)
I would change the part of Monckton’s paper citing the 0.152C/W/m2 to something between 0.184C/W/m2 to 0.23C/W/m2 just based on how the calculations should be done. Not a big change, but a change nonetheless.
Frankly, I still don’t see how AGW proponents get around the null hypothesis of natural change – particularly when there appears to be evidence for far greater temperature changes over far shorter timeframes in the past. PETM as one example, where it appears that at least at one point there was a 10 degree shift in only a couple of decades. The rate and magnitude, even the max temperatures, of recent changes (say since 1950, or even 1900), don’t appear to be out of the ordinary for even the Holocene – at least not as best as we can presently determine.
So why does this first, most basic step of the scientific method seem to be so roundly ignored? If climate has shifted so drastically long before man began adding any fossil fuel CO2 to the atmosphere, how can the claim be made that such a relatively small temperature shift in the present day should somehow be attributed to anything other than natural causes? Even the isotopic ratio that was used as supposed identification of man’s CO2 contribution to the increase is now apparently under question in the peer reviewed literature, where we are at about the right point for the CO2 temperature lag from the Little Ice Age to be kicking in.
Shouldn’t we understand natural variability before assuming we’re somehow out of it, when we haven’t even met the requirements necessary to supersede the null hypothesis?
Lucia, how do you justify ignoring the null hypothesis? Or anyone else here?
Rational Debate:
At September 28, 2011 at 8:32 pm you ask:
“Lucia, how do you justify ignoring the null hypothesis? Or anyone else here?”
I think I qualify as “anyone else” so I answer for myself.
The null hypothesis stands and should not be ignored (search WUWT to see my strong views on this) but it is not relevant to this thread.
Chris Monckton has taken the IPCC model and shown that when empirical data is inserted for the constants in the model then that model indicates only minor (i.e. not catastrophic) global warming will result. That is a very important result.
His work has been disputed – notably by Lucia – on the basis that his empirical data are not correct. This would be a valid criticism if it were true but it is an unfortunate fact that Lucia’s choice of language and subsequent behaviour have obscured the criticism. There does seem to be a concern that Monckton used a value of 0.15K W-1 m2 where 0.18K W-1 m2 may have been more appropriate, but either value would make no significant difference to his result so the criticism seems unfounded.
The subject of this thread is important in its own right. It is sad that the subject has been somewhat obscured by a slanging match, and the sadness would be increased if it were further obscured by discussion of the null hypothesis.
Richard
It may be of interest to readers to know how the IPCC determines climate sensitivity to a given increase in CO2 concentration. First, consider the position in the absence of temperature feedbacks. In the IPCC’s method, the transient no-feedbacks climate sensitivity, in Kelvin (the amount of warming we might actually see in the 21st century as a result of adding CO2 to the atmosphere, but without taking account of any resulting temperature feedbacks), is approximately equal to the natural logarithm of the proportionate increase in CO2 concentration. We can use this very simple formula to demonstrate the ever-diminishing returns from adding CO2 to the atmosphere over the next century that some commentators here have rightly pointed out:
Suppose we start with 400 ppmv today and add successive increments of 100 ppmv until we reach 800 ppmv by the end of the century, close to the IPCC’s central estimate on its A2 emissions scenario. Then the no-feedbacks transient sensitivity in response to each additional 100 ppmv of CO2 concentration would fall quite rapidly:
400-500 ppmv: delta-T(transient) = ln(500/400) = 0.223 K
500-600 ppmv: delta-T(transient) = ln(600/500) = 0.182 K
600-700 ppmv: delta-T(transient) = ln(700/600) = 0.154 K
700-800 ppmv: delta-T(transient) = ln(800/700) = 0.134 K: total 0.693 K
Checksum: delta-T(transient) = ln(800/400) = ln 2 = 0.693 K. Nice when it works!
To allow for feedbacks, multiply by 14/5 to give transient with-feedbacks CO2-driven warming of 1.940 K over the 21st century. In other words, even if we were to shut down the world’s economy right now, without even being allowed to light a carbon-emitting fire in our caves, the IPCC’s central estimate is that the warming forestalled in the 21st century after a doubling of CO2 concentration would only be around 2 K at most.
It is that simple fact which – more than any other – guarantees that any measure to try to forestall global warming by taxing, trading, regulating, reducing, or replacing CO2 emissions cannot by any stretch of the imagination be cost-effective.
Two-thirds of 1.940 K – or 1.293 K – represents the additional warming that will occur between the end of the 21st century and the point 1000-3000 years later (Solomon et al., 2009) when equilibrium sensitivity is reached. That gives total no-feedbacks CO2-driven equilibrium warming of 3.233 K. We don’t need to worry about this additional 1.3 K in policy terms, because it will occur so slowly that our children’s children will have plenty of time to adapt – and the warming might even stave off the next (and long-overdue) ice age, which would kill a lot more of us and our fellow-life-forms than global warming ever will.
Check: The IPCC’s central estimate of equilibrium sensitivity to a doubling of CO2 concentration, after including feedbacks, is 3.26 K (IPCC, 2007, p. 798, Box 10.2).
To allow for emissions of other greenhouse gases in the 21st century, the IPCC multiplies by ten-sevenths to bring the equilibrium warming up to 4.62 K. Dividing this by 5/3 gives transient all-forcings warming – the warming that the IPCC imagines might actually occur in the 21st century – of around 2.8 K.
Trouble is, as my commentary pointed out, it ain’t happening – not at even half the predicted rate, and there are numerous empirical and theoretical reasons why it ain’t gonna happen. Enjoy the sunshine!
Keep looking, there’s gotta be a rabbit of global warming in that hat somewhere.
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Richard S Courtney
I don’t.
Also, I am puzzled why you are bringing up this question when because what you call the nulll hypothesis is irrelevant to Monckton’s errors in paragraph 3 of his letter to RS.
Monckton
I note read your comment “Monckton of Brenchley says: September 29, 2011 at 4:49 am ” and note that you have not engaged my comment “lucia says:
September 28, 2011 at 3:40 pm ” in which I wrote:
I would like to clear up this matter, and request that you provide quotes to clarify what you intend to suggest when you say I mislead my readers on some point.
In addition, I would like you to clarify what you claim in your post when you write
To clarify, I request you reveal what relationship you believed Kiehl and Trenberth (1997) assumed , where you think you have used this relation; doing so should involve pointing to an equation text present in in K&T (1997).
As for what I have done: I have criticized use of equation (18) in Kimoto, saying Planck parameters computed using that relation are as likely to be correct as those computed by pulling a number out of a hat. This equation most certainly does not appear in Kiehl and Trenberth. If you can find evidence they assumed Kimoto’ equation (18) in that paper, please provide it explicitly.
I would also like you to justify that Kiehl and Trenbert (1997) somehow get an “implicit λ0 is 0.18” (W/m^2)
These questions relate simultaneously to substantive technical points, to issues of fact about what K&T 1997 actually says and to your accusation that I have mislead readers. I would like to see you provide support for what you are claiming.
lucia, Richard was answering someone else. How can I get things straight in my head when lucia keeps putting things in my speech.
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Monckton of Brenchley says:
September 29, 2011 at 4:49 am;
400-500 ppmv: delta-T(transient) = ln(500/400) = 0.223 K
500-600 ppmv: delta-T(transient) = ln(600/500) = 0.182 K
600-700 ppmv: delta-T(transient) = ln(700/600) = 0.154 K
700-800 ppmv: delta-T(transient) = ln(800/700) = 0.134 K: total 0.693 K
Checksum: delta-T(transient) = ln(800/400) = ln 2 = 0.693 K. Nice when it works>>>
I believe you still have the math wrong. Your check sum works because you’ve calculated the formula correctly. That doesn’t mean that you have used the correct formula.
IPCC >> CO2 Doubling = 1 Degree K
400 x 2 = 800 = 1 degree K.
You\ve gotten just under .7 degree.
In a rush right at the moment but I’ll try and get back to this later in the day.
Kim-
Thank you for pointing out Richard was answering not asking the question posted by Rational Debate. It appears Richard and I both agree the question is irrelevant to the current post.
To David Hoffer: No, I don’t have the math wrong. Read carefully! I was talking of transient no-feedbacks sensitivity, not equilibrium no-feedbacks sensitivity, so 0.7 K this century (compared with 1.2 K in total by a couple of millennia hence) is correct.
To Lucia: There are no errors in my para. 3: see the posting “1 K or not 1 K, that is the question”.
To Richard Courtney: Many thanks for kindly drawing attention to the fact that the 1 K result, obtained by so many distinct methods, may be important. It is good to have an IPCC reviewer on the team, as it were. I’ too, regret that a misleading and rather vexatious attempt to divert attention from the potential importance of the overall result was made: but, thanks to you and others, that attempted disruption has failed and the commentary is circulating very widely now.
To all: thanks again for your interest, and enjoy the most recent posting, posting in which I try to reply to as many of the points of substance in this discussion as I can.
re post by: Richard S Courtney says: September 29, 2011 at 1:56 am
Yes, you definitely qualify. 😉
Richard, thank you for the reply. Yes, I completely agree with you on all counts. The problem is that there hasn’t been a recent thread where the question would be more relevant (unless I missed one). In one sense it is relevant here – that being that if the AGW hypothesis isn’t even comparable to the null, then there shouldn’t even be a need to debate various aspects of the AGW hypothesis. That said, since obviously everyone, including of course the IPCC, governments, and on and on, have skipped right past the null and are foisting AGW policies and costs upon us all, then as you say, work such as this presented by Lord Monkton is very important in its own right.
So while on the one hand I hate to ‘water down’ this thread with a discussion of the null, it is a thread that some strong AGW proponents who are scientists or educated advocates (e.g., not just talking point regurgitators) appear to be following and commenting on, and they are the very ones that can explain why climate scientists ignore the null. So I asked (and my apologies to Lord Monkton for the tangential diversion). Darn I wish that comment sections such as this had powerful or flexible enough options to allow someone to post a question as I did, then duplicate the comment in an entirely new comment thread, with a pointer/link on the original comment to that new thread. That way the folks on the original thread you were hoping for replies from would see it and hopefully follow to the new thread to answer, but the existing/old thread wouldn’t be disrupted by the tangential conversation. Ah well, so it goes.
p.s., I will search a bit for your prior comments on the issue, and see what sort of replies you got.
For that matter, I’d LOVE to hear Lord Monkton’s take on the null hypothesis too! But fully understand if he’s not inclined to dilute this thread with it. I would be delighted to see his thoughts on the issue. If he’s interested or willing to give his views on the issue to me but doesn’t want to dilute this thread, he’s more than welcome to email a reply to me at: RationalDebate “at” gmail “dot” com.
As is anyone else for that matter.
re post by: lucia says: September 29, 2011 at 7:24 am
You don’t ignore it because you believe AGW hypothesis is equal to or supersedes it? If so, why? Or you don’t ignore it because you believe it stands, but debate aspects of AGW because of it’s current position politically etc?
As to why I bring it up here:
**Because if the null hypothesis stands, we shouldn’t even need to continue debating various aspects of the AGW hypothesis such as this thread – and ought to be requiring AGW climate scientists and proponents to justify going beyond the null. Yet it rarely seems to come up.
**Because there are a number of people active on this thread whom I respect, such as Lord Monkton and yourself, and would very much like to hear their opinion on this foundation issue of the entire AGW debate.
A post worth re-reading, I think, one which may have been lost in the noise:
Dewald says: September 28, 2011 at 5:37 am
Lightly paraphrased:
– – – – – – – – – – – – – – – – –
IMHO opinion the feedback discussions are moot.
… based on the fact that I can see the sun with my eyes: every molecule in earth’s atmosphere (gas, water vapor, particulates..) has a sight factor that is greater towards space than towards the earth or all other molecules in the atmosphere.
The temperature delta between said molecule and space is much greater that the temperature delta between said molecule and earth or other molecules.
The sight factor between the sun and the earth’s surface is much greater than the sight factor between the sun and and all the molecules in the atmosphere, based on the fact that I can see the sun with my eyes.
… Man can’t do anything to change the temperature of the atmosphere [dramatically] unless he can change the laws of electromagnetic radiation.
– – – – – – – – – – – – – – –
I would add, Dewald, that GHGs accomplish what adding an an LC Electro-Magnetic wave ‘filter’ (RF filter) does in line to a transmission line carrying RF (high frequency or “Radio Frequency”) energy:
There will be some attendant ‘phase delay’ though the filter, due in large part to the effect that some amount of energy is ‘stored’ for a short period of time in the reactive (L and C) components as the fields build up in the coils and capacitors in said filter, above and beyond what would be ‘stored’ in a physical (not electrical) equivalent length of transmission line (on the order of just a few centimeters).
Eventually, equilibrium is achieved: though, and power flow _in_ equals power flow _out_ (assuming lossless components for this mind experiment!) …
One can see this effect in some of the more exotic filter implementations, such as in Elliptical filters near cutoff, where the individual filter component current and voltage values reach ‘peaks’ many times the filter’s input port current and voltage values, -yet- the energy _flow_ into and out of the filter remains constant and equal (again, neglecting losses in components).
The difference is, the temporary _stored_ energy within the fields (electric field in the capcitors and magnetic field in the inductors) of the reactive, non-power dissapative elements (the L and C elements) making up the filter.
So, too inserting a bunch of ‘resonant’ gas molecules (CO2 and H2O plus others like CH4 etc) will act to add ‘phase delay’ to transiting LWIR leaving the surface of the globe, to space, but eventually some amount of ‘equilibrium’ is reached, for the present anyway …
.
davidmhoffer says:
(1) That’s because 400 to 880 ppm is more than doubling the concentration, so an increase in temperature by more than 1 C is expected.
(2) As I noted in my post http://wattsupwiththat.com/2011/09/27/monckton-on-pulling-planck-out-of-a-hat/#comment-754595 , your value of 0.6 C for going from 280 to 400 ppm is not quite right if you assume the sensitivity to be 1.0 C per doubling. However, since the actual reported no-feedback sensitivity is slightly larger than 1.0 C per doubling, I went with your 0.6 C for going from 280 to 400 ppm and made my computations of the temperature increases for subsequent 120 ppm increases of CO2 concentration on that basis. (This corresponds to a climate sensitivity value of ~1.166 C per doubling.)
Yes. For example, look at the rise for going from 280 to 400ppm of 0.6 C and the rise for going from 400 to 520 ppm of 0.44 C. Now, suppose that the amount of carbon dioxide we emit into the atmosphere is also rising about exponentially with time (as it has been). In particular, suppose that the emissions rates averages 36% higher during the 400 to 520 ppm rise than it averaged during the rise from 280 to 400 ppm. Then, that would mean that the two rates of temperature increase with time would be equal.
The point is that a logarithmic dependence does not lead to as nearly as dramatic a decrease in temperature increment on the concentration increment as you imagined. Hence, it is not that hard for us to more than compensate for this decrease by our ever increasing rate at which we emit CO2 into the atmosphere. (And note that a mere 2% increase in our CO2 emissions each year leads to a doubling…i.e., 100% increase…in those emissions every ~35 years.)