Guest post by Christopher Monckton of Brenchley
Abstract
Global CO2 emissions per unit increase in atmospheric CO2 concentration provide an independent constraint on climate sensitivity over the timescale of the available data (1960-2008), suggesting that, in the short term and perhaps also in the long, climate sensitivity may lie below the values found in the general-circulation models relied upon by the IPCC.
Introduction
The Intergovernmental Panel on Climate Change (IPCC, 2001, p. 358, Table 6.2), citing Myhre et al. (1998), takes the CO2 forcing ΔF as 5.35 times the logarithm of a proportionate change Cb/Ca in CO2 concentration, where Cais the unperturbed value. Warming ΔT is simply ΔF multiplied by some climate sensitivity parameter λ.
Projected 21st-century anthropogenic warming, as the mean of values on all six IPCC emissions scenarios, is 2.8 K (IPCC, 2007, table SPM.3: Annex, Table 0). Of this, 0.6 K is stated to be in the pipeline. Of the remaining 2.2 K, some 0.65 K is attributable to non-CO2 forcings, since the CO2 fraction of anthropogenic warming is 71% (the Annex explains the derivation). Thus the IPCC’s current implicit central estimate of the warming by 2100 that will be attributable solely to the CO2 we emit this century is only 1.56 K.
Projected CO2 concentration C2100 in 2100, the mean of the values on all six IPCC emissions scenarios, is 713 ppmv (Annex, Table 3), 345 ppmv above the 368 ppmv measured in 2000 (Conway & Tans, 2011). Therefore, the IPCC’s implicit climate-sensitivity parameter for the 21st century is 1.56 / [5.35 ln(713/368)], or 0.44 K W–1 m2. This value, adopted in (1), is half of the IPCC’s implicit equilibrium value 0.88 K W–1 m2 (derived in the Annex).
Global warming from 1960-2008
The IPCC’s implicit central estimate of CO2-driven warming from 1960-2008 is at (1):
The CO2 forcing coefficient 5.35 was given in Myhre et al. (1998). Initial and final CO2 concentrations were 316.9 and 385.6 ppmv respectively (Tans, 2012). Since the 0.46 K warming driven by the CO2 fraction is 71% of anthropogenic warming, use of the IPCC’s methods implies that, as a central estimate, all of the 0.66 K observed warming from 1960-2008 (taken as the linear trend on the data over the period in HadCRUt3, 2011) was anthropogenic. However, attribution between Man and nature remains problematic: an independent approach to constraining climate sensitivity produces a very different result.
An independent constraint on climate sensitivity
Since few non-linearities will obtrude at sub-centennial time-scales, to warm the Earth’s surface by 1 K the CO2 concentration in the atmosphere must increase by 345/1.56 = 223 ppmv K–1. From 1960-2008, the trend in the ratios of annual global CO2 emissions to annual increases in atmospheric CO2 concentrations does not differ significantly from zero (Fig. 1). The mean emissions/concentration-growth ratio over the period was 15.5 Gt CO2 ppmv–1, which, multiplied by 223 ppmv K–1, gives 3450 GTe CO2 K–1, the quantum of CO2 emissions necessary to raise global temperature by 1 K.
Figure 1. Near-zero trend in annual emissions/concentration-growth ratios, 1960-2008. Data and methods are described in the Annex. Spikes caused by volcanic eruptions are visible. Excluding effects of major eruptions makes little difference to the outcome.
Total global CO2 emissions from 1960-2008 were 975 Gte CO2 (Boden et al., 2011). Accordingly, CO2-driven warming expected over the period, by the present method, was 975 divided by 3450, or 0.28 K. Allowing for the non-CO2 fraction, some 0.40 K warming over the period, equivalent to 61% of observed warming, was anthropogenic, not inconsistent with the estimate in IPCC, 2007 that at least 50% of observed warming from 1950-2005 was anthropogenic. However, inconsistently with (1), this method yields a CO2-driven warming that is only 61% of the central estimate derived from the IPCC’s general-circulation models.
Implications
On the assumption that the coefficient in the CO2 forcing function, cut from 6.3 to 5.35 in Myhre et al. (1998), is now correct, one implication of the present result is that the climate-sensitivity parameter λ appropriate to a 50-year period is not 0.44 K W–1 m2, as the models suggest, but as little as 0.27 K W–1 m2. Since the value of the instantaneous or Planck sensitivity parameter λ0 is 0.31 KW–1 m2 (IPCC, 2007, p. 631 fn.), temperature feedbacks operating during the period of study may have been somewhat net-negative, rather than appreciably net-positive as implied by (1).
If feedbacks operating over the short to medium term are indeed net-negative, there is no warming in the pipeline from past emissions; in the rest of this century CO2-driven warming may be little more than 1 K; anthropogenic warming from all sources may be less than 1.5 K; and supra-centennial-scale warming may also be significantly less than currently projected. If so, all attempts at mitigation will prove cost-ineffective, and the cost of adaptation to future warming will be well below current estimates.
References
Boden, T., G. Marland, and R. Andres, 2011, Global CO2 Emissions from Fossil-Fuel Fossil-Fuel Burning, Cement Manufacture, and Gas Flaring: 1751-2008, available from http://cdiac.ornl.gov/ftp/ndp030/global.1751_2008.ems
Conway, T., & P. Tans, 2011, Recent trends in globally-averaged CO2 concentration, ww2.esrl.noaa.gov/gmd/ccgg/trends/global.html#global.
Garnaut, R., 2008, The Garnaut Climate Change Review: Final Report. Cambridge University Press, Port Melbourne, Australia, 680 pp, ISBN 9780521744447.
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.
Myhre et al., 1998, New estimates of radiative forcing due to well mixed greenhouse gases. Geophysical Research Letters25:14, 2715–2718, doi:10.1029/98GL01908.
Ramanathan, V., R. Cicerone, H. Singh and J. Kiehl, 1985, Trace gas trends and their potential role in climate change, J. Geophys. Res.90: 5547-5566.
Solomon, S., G.-K. Plattner, and P. Friedlingstein, 2009, Irreversible climate change due to carbon dioxide emissions, PNAS 106:6, 1704-1709, doi:10.1073/pnas.0812721106.
Tans, P., 2012, Atmospheric CO2 concentrations (ppmv) at Mauna Loa, Hawaii, 1958-2008, at ftp://ftp.cmdl.noaa.gov/ccg/co2/trends/co2_annmean_mlo.txt.
Acknowledgements
The author is grateful to Dr. Patrick Michaels for having drawn his attention to the near-zero-trend in the annual CO2 emissions/concentration-growth ratios that is confirmed here.
Annex: supplementary material
Values of the climate sensitivity parameter λ
If net temperature feedbacks exceed zero, the climate sensitivity parameter λ is not constant: as longer- and longer-acting feedbacks begin to act, it will tend to increase between the time of a forcing to the time when equilibrium is restored to the climate 1000-3000 years after the forcing that perturbed it (Solomon et al., 2009). Illustrative values of λ are given below.
The sensitivity parameter derived from the present result and applicable to the 49 years 1960-2008 is 0.27 K W–1 m2.
Where temperature feedbacks sum to zero, the instantaneous value λ0 is 0.31 K W–1 m2 (derived from IPCC (2007, p. 631 fn.: see also Soden & Held, 2006).
Garnaut (2008) talks of keeping greenhouse-gas rises to 450 ppmv CO2-equivalent above the 280 ppmv prevalent in 1750, so as to hold 21st-century global warming since then to 2 K, implying λ262 = 2 / [5.35 ln{(280 + 450) / 280}] = 0.39 K W–1 m2.
As explained in the text, the IPCC’s implicit climate-sensitivity parameter for the 21st century is λ100 = 1.56 / [5.35 ln(713/368)] = 0.44 K W–1 m2.
On each emissions scenario, the IPCC’s estimate of the bicentennial-scale transient-sensitivity parameter λ200 is 0.49 K W–1 m2 (derived in Table 0), a value supported by IPCC (2001, p. 354, citing Ramanathan, 1985).
The implicit value of the equilibrium-sensitivity parameter λequ is the warming currently predicted in response to a CO2 doubling, i.e. 3.26 K (IPCC, 2007, p. 798, Box 10.2), divided by the forcing of 5.35 ln 2 = 3.71 W m–2 at that doubling. Thus, λequ = 0.88 K W–1 m2.
Additional tables in the annex (which cannot reproduce properly here in blog format) are in the PDF file for this paper:
monckton_climate_sensitivity (PDF)
Tom P:
In response to your post addressed to me at September 4, 2012 at 5:20 am, I commend that you take note of my post addressed to you at September 4, 2012 at 2:58 am. I repeat that it was sincere and kindly.
Richard
Mr Monckton.
In all of this you have assiduously avoided addressing Tom P’s substantive points. You rail against his name, but it matters not a whit if he styles himself as Peter Pan if his argument is sound, and thus far you have done nothing to demonstrate that Tom P is incorrect.
Oh, there’s been a lot of huffing and puffing, but anyone who is numerate can see quite plainly that you are prevaricating. Indeed, it seems that you are caught in a recursive loop of avoidance, so I would suggest a simple way to break the deadlock.
Write your “proof of an independent constraint on climate sensitivity” in exactly a form that would be presented to a professionally reviewed journal. You know, similar to the draft paper that Anthony Watts released just over a month ago. Include in it a rebuttal of Tom P’s disputation. Doing so will not only cement your case if you are correct, it will also show that you understand the mathematics and physics sufficiently that you are able to engage at that level.
If you can construct such an argument, then real scientists might take you seriously. Otherwise, all you are good for is fodder for the so-called “skeptical side”.
Bernard J.
Are you Tom P? Please tell.
Richard
There is a post on the Hockey Stick and the Yamal trees centered around Tom P:
More broken hockey stick fallout: Audit of an Audit of an Auditor
http://wattsupwiththat.com/2009/09/29/more-broken-hockey-stick-fallout-audit-of-an-audit-of-an-auditor/
Tom P at WUWT
http://tinyurl.com/ckh86bf
Paolo,
Don’t forget my tussles with Steven Goddard with his perpetual promises of an arctic ice recovery. He never accepted his ice thickness calculations were wrong, though the money he lost this melt season might concentrate his mind.
That reminds me, I have that bet with Charles the Moderator on whether 2008 was the start of a cooling trend…
“Tom P.” and “Bernard J”, both skulking behind pseudonyms (and perhaps, as Dr., Courtney points out, the same person – just one reason why pseudonyms are a bad idea), merely repeat “Tom P.”‘s original and very silly error, which I have already fully dealt with. “Tom P.”, thoroughly defeated, now resorts to a combination of semantic quibbling and vituperative, ad-hominem remarks.
One need say no more about the ad-hom remarks except that they are characteristic of the climate-extremist movement; that they are one of the chief reasons why it has so abjectly lost the argument; and that they constitute a sub-species of the fundamental fallacy of logic known to the medieval schoolmen as ignoratio elenchi (ignorance of the appropriate manner of conducting an argument, in that red herrings are introduced).
As to the semantic quibble, the IPCC came to one value for climate sensitivity and I came to another. The two results are self-evidently different. However, I used values for both CO2 emissions and CO2 concentrations in reaching my value. The purpose of using the CO2 emissions was to establish what fraction of the observed warming from 1960-2008 was represented by changes in CO2 concentration, which stand in a near-invariant ratio to changes in CO2 emitted.
Where the ratios of CO2 emissions growth to CO2 concentration change and of CO2 concentration change to temperature change are broadly constant, the ratio of CO2 emissions growth to temperature change will also be broadly constant, and “Tom P. / Bernard J.” continue, erroneously, to insert a quite unnecessary additional term into the equation.
Dr. Courtney is an IPCC reviewer. I know who he is and what his qualifications are. Because I do not know who “Tom P. / Bernard J.” is, I do not know at what level I should pitch my replies to his/their arguments. But it appears that he/they do not have a good grasp of elementary mathematics, which is perhaps why they are insufficiently equipped, intellectually speaking, to comprehend their error.
Christopher Monckton claims, “Tom P now resorts to … vituperative, ad-hominem remarks.”
Really? Where?
I have looked through the last several of Tom P’s comments and find not a single comment that could be so characterised.
Christopher Monckton, on the other hand, has interacted with those with whom he is in dispute in the following terms:
“Mr. [Xxxxx] should really not waste any more time displaying his bottomless ignorance on this site.
he tries – I fear deliberately – to muddy the waters
All he does with his childishly petulant and shamefully ill-informed interventions is to clarify before everyone the depth and breadth of his own ignorance. his interventions are perhaps of value in that they are yet further visible evidence of the sad level of general scientific and forensic ignorance
it is intellectually dishonest of “[Xxx X]” who continues to lurk furtively behind a pseudonym
Mr. [Xxxxx] whines … Let him do some reading before he makes a still greater idiot of himself …
it is intellectually dishonest of him … “
Christopher Monckton,
Your inconsistencies, both mathematical and rhetorical, are both so clearly displayed to anyone who cares to read this thread, there’s little to add. But you additionally seem now to be confused by Mr. Courtney (I am led to believe he has no PhD) that for some reason I might share an identity with Bernard J.
Bernard J. is just making a question that I’m sure has crossed the minds of nearly all who have read this thread (I feel I should except the mind of Mr. Courtney): where is your working to rebut the calculation I presented September 1, 2012 at 3:36 pm that emissions gives a warming of 0.44 K, rather than the 0.28 K you erroneously calculated?
You have had five days to work on this, and attempt a rescue of your claim that you have discovered an independent constraint on warming. Without any rebuttal, this thread demonstrates something rather different to what you set out to prove.
Tom P. merely reasserts a position that I had already demonstrated to be false. An independent constraint on climate sensitivity now exists.
Christopher Monckton claims, “An independent constraint on climate sensitivity now exists.”
Hubris.
Only when your article has been peer reviewed and published in a reputable journal and withstood the scrutiny of the scientific community would you be entitled to make such a claim.
TomP:
With respect to your comment about me, at least you have not presented the usual warmist lie that Monckton of Brenchley is not a Lord. Such demeaning of people is normal by warmists, but it is reprehensible.
Richard
Slioch:
Your post at September 7, 2012 at 1:17 am says
Clearly, you have no understanding of science and/or logic.
Every scientific finding may be – probably will be – overthrown in time, but it cannot be said that a scientific finding does not exist merely because you don’t like how and where it was published.
According to you Newton did not provide an independent assessment of gravity, Einstein did not provide a theory of relativity, and the Wright brothers did not establish aeronautics.
There were no peer-reviewed journals for Newton to publish in, the relativity papers were published in Nature without being put to peer review, and the seminal work on aeronautics was published as an article in a magazine about bee keeping.
Play the ball and not the man.
Richard
Richard Courtney
Even the very preliminary assessment of Monckton’s article provided by this forum has indicated there may be serious problems with it. My assessment, for what it’s worth, is that it would never pass peer review, but if Monckton wishes to attempt that hurdle then let him do so. Until such time, don’t expect those who find fault with it to agree that “An independent constraint on climate sensitivity now exists.”
As for your comparison – however tenuous – between the preliminary status of Monckton’s efforts and those of Newton and Einstein… . Really, don’t be ridiculous.
The Internet is awash with all manner of strange ideas. Are we to accord preliminary acceptance of these just because in the past major advancements have passed through a similar stage?
BTW, I do love the juxtaposition of “Clearly, you have no understanding of science and/or logic.” with “Play the ball and not the man.” Quite delicious.
Slioch:
I explained how and why your post demonstrates “you have no understanding of science and/or logic”. And your response provides further examples.
I played the ball, not the man.
But you …
Richard
Mr Courtney,
Your commented:
“With respect to your comment about me, at least you have not presented the usual warmist lie that Monckton of Brenchley is not a Lord. Such demeaning of people is normal by warmists, but it is reprehensible.”
There is no doubt Monckton is a lord, though purely by accident of birth. The US wisely dispensed with deferring to anyone by their title merely on the basis of parentage.
It should be added Monckton has not a happy relationship with the House of Lords:
http://www.parliament.uk/business/news/2011/july/letter-to-viscount-monckton/
In fact Monckton tried to attain an elected position in that House, but his candidacy gained precisely zero votes.
Of course, this has nothing to do with the flawed mathematics of Monckton’s post. He has failed to produce any rebuttal of the calculation I presented September 1, 2012 at 3:36 pm. You seem to be the only defender of Monckton’s position left. Maybe you could oblige?
Messrs Monckton and Courtney.
I most certainly am not Tom P, although I am utterly delighted to be confused with him. However, anyone familiar with the various mainstream climate blogs would know that I post under just the one name – I don’t have time for sock puppetry – and that I speak in a different voice to Tom P. If you doubt this, ask the moderators here to check the IP addresses as they often do – they’ll demonstrate that Tom and I are not only in different places, but likely in very different parts of the world.
I elect not to use my full name because I learned long ago, to my bitter frustration, that to do so invites so much spam as to render my institutional email accounts entirely unusable. There’s also the secondary fact of having been threatened with physical harm on at least one occasion when I posted of a forum that allowed private messaging. It should matter not though whether you know my identity or Tom’s – the fact of his rebuttal of Monckton’s ‘analysis’ is sufficient that the discussion should focus on that only. And after all, there are countless dismissers of global warming on this blog who are even more anonymous than I – ‘Smokey’ for example – and whose posts are never questioned just because they are anonymous.
The substantive point remains. Tom P has constructed a straighforward mathematical refutation of Monckton’s “proof”. If Monckton disputes the refutation he has but to construct his own mathematical demonstration, side-by-side with Tom P’s if need be, and demonstrate with equations and the cold, hard logic of mathematics and physics where he is correct and where Tom P is not. If Monckton has faith in his “proof”, he would construct his argument in exactly this fashion, as if preparing for publication, because his “proof” is (or should be) intended to refute the scientific consensus, and not to simply convince the ‘sceptical’ laiety using ambiguous waffle.
Don’t be concerned about my ability to understand a highly mathematical explanation, Mr Monckton. I completed two years’ study of the subject in my undergraduate degree, and I’ve used it routinely in my Masters and PhD work, and in my professional positions. If you attend to presenting your case clearly and comprehensively, I will attend to the simple task of understanding it.
And of course, when all is said and done, it doesn’t matter if I am but a chimney sweep – Monckton’s claim is what it is, and should be presented and defended at the level that it can be unambiguously understood by professional experts in the field.