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)
richardscourtney says:
September 1, 2012 at 10:55 am
Tom P says:
September 1, 2012 at 11:01 am
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Plants, oceans and soils are absorbing 2.0% per year of the excess CO2 in the atmosphere above the equilbrium level of 276 ppm.
I say equilibrium level because that is what it has been for the past 24 million years (give or take a 185 ppm in an ice age) and roughly what is was for the 8,000 years before our emissions started in earnest about 1750.
If we stopped emitting tomorrow, plants oceans and soils would go on absorbing 2.0% per year of the excess CO2 and, in about 100 years, we would be back to 291 ppm.
–> CO2 concentration increase ppm = Human Emissions ppm – Natural Carbon Sink Rate
–> CO2 concentration increase ppm = Human Emissions ppm – [0.02 (CO2 curr ppm * 2.13 – 276 ppm * 2.13) / 2.13]
–> for 2011 = 1.92 ppm = 4.3 ppm – [0.02*(827-589)/2.13] = 4.3 – 2.38 = 1.92 ppm
–> for 1950 = 0.2 ppm = 0.83 ppm – [0.02*(663-589/2.13] = 0.83 – 0.63 = 0.2 ppm
This formula works very close for any year between 1950 and 2011 (prior to that the 0.02 was a little lower).
(the 2.13 is required to go between Carbon and CO2 because most of the data is in billion tons Carbon and, in the sinks, the Carbon is held is different Carbon-based molecules than CO2).
Greg House says:
September 1, 2012 at 12:00 pm
That is exactly what I am doing, considering “greenhouse gases warming” by itself, and by itself it excludes a negative feedback and includes a positive feedback.
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If you are including a feedback, you cannot say in the same breath that you are considering CO2-induced warming *by itself.*
Either you consider it by itself or you don’t. If you include feedbacks, you need to consider all plausible feedbacks, not only the ones you like. For example, more water vapor doesn’t mean only more water vapor, it also means more clouds and therefore an increased albedo.
I will misericordiously assume you are just trolling and leave it at that.
The IPCC says that if CO2 was not emitted after 2000, the temperature rise would be 0.6 K, which is in the pipeline. What happens if we continue to emit CO2 through 2100? We get a rise of 2.8 K. Everyone agrees so far. Where we disagree is what is the net loss from the pipeline if the CO2 continues to rise because that can be subtracted from 2.8 K to get the real heating of CO2 in the 21st century. Monckton assumes all the 0.6 degrees is lost from the pipeline, leaving nothing in the pipeline at the end. I (and the IPCC) would argue that there is no net loss from the pipeline (possibly a gain), simply because CO2 still provides energy to the pipeline at the rate it is lost. You only get that energy out, in the net, if CO2 stops putting energy in, which only occurs if emission stops. In short, 2.8 K is the real gain, as the fluxes to/from the pipeline tend to cancel.
Monckton of Brenchley says:
September 1, 2012 at 1:55 pm:
“Mr. House states, meaninglessly, that “the greenhouse-gases warming notion alone supports only a positive feedback”. That is incorrect. …For these reasons, Mr. House’s assertion that anyone who assumes there is a greenhouse effect must also assume net-positive feedbacks is a grave misunderstanding of the elementary equations of climatological physics.
Mr. House goes on to say that I maintain a negative feedback is possible. …He then complains that I did not demonstrate that any negative feedback actually exists in the real climate, and does so immediately after mentioning one such negative feedback himself – evaporation.”
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For the like 20th-30th time on this blog I have to start my answer to Christopher Monckton with the words “I did not say that” (sad). Christopher, I did not say “net-positive”, I said “positive”, these are 2 very different things. There can be a positive feedback but with a negative net-result because of other negative feedbacks, if there are any, of course, this is so obvious.
Second, I would like you to prove your statement that evaporation is a negative feedback in the context of alleged “greenhouse property” of water vapour. In other words, you can not take the evaporative cooling out of the context, because the process of evaporation leads also to a higher concentration of the “greenhouse gas” water vapour and thus (according to the AGW concept) contributes to warming. So, evaporation cools but water vapour allegedly warms, and you need to prove that its cooling effect is stronger that its warming effect. If you can not do that, your statement about evaporation being a negative feedback has no basis. I am looking forward to your scientific answer on this point. If you do not have any, you might consider a possibility to come up with another “negative feedback”, but please do not forget, that the “global warming”, “global temperature” etc. is about the surface temperature.
Paolo says:
September 1, 2012 at 2:09 pm:
Greg House says:
September 1, 2012 at 12:00 pm
That is exactly what I am doing, considering “greenhouse gases warming” by itself, and by itself it excludes a negative feedback and includes a positive feedback.
If you are including a feedback, you cannot say in the same breath that you are considering CO2-induced warming *by itself.* Either you consider it by itself or you don’t.
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The alleged contradiction is not real, it is only the result of your possible misunderstanding, because you made “CO2-induced warming” out of my “greenhouse gases warming”.
Again, the “greenhouse gases warming” concept includes BOTH “CO2 induced warming” AND “water vapour induced warming”, and since “CO2 induced warming” produces more water vapour it produces thus also more “water vapour induced warming”, and this is a positive feedback.
Christopher Monckton again fails to understand or address the error (not errors) in his introductory paragraph that renders his estimate of climate sensitivity incorrect. I have made very clear what that error is, not least in my post of September 1, 2012 at 6:53 am. It is such an elementary error to deduct a value for an “in the pipeline” warming in 2000 without then adding a similar value in 2100 that I struggle to understand how anyone could not see that error. The error, incidentally, is in no way the fault of the IPCC and lies entirely at Monckton’s door. However, I do not intend to waste further time on the issue. No doubt, if there are any scientists of merit in those he has asked to review his article then they will point out this error to him once again.
Monckton is also apparently unable to recognise the conditional and illustrative nature of the derivation of the 0.75K per W/M^2 figure, even though I have stressed that to be the case. It was simply to point out what the “in the pipeline” value would have to be in 2100 in order to suggest a climate sensitivity for a doubling of CO2 of around 3K [since 0.75*5.35*ln2 = 2.78]. That “in the pipeline” warming in 2100 would need to be 1.1C if the value in 2000 is 0.6C. Since the proportionate rise in CO2 is greater in the 21st century than the 20th, that is not an unreasonable proposition, but that is all it is.
Christopher Monckton,
Your plot is of the rate of change of emissions growth divided by the rate of change of CO2 concentration, and hence the intercept only gives the slope of the relationship between cumulative emissions and atmospheric concentration. You also need the intercept in that relationship to be able to convert between the two and hence put the right numbers in to your equation 1.
Your error at this point should be quite clear, but here are the numbers, as you insist. Substituting equation (2) above,
C = k E + Co,
into
deltaT = 0.44*0.53*ln(C2/C1)
where C1 and C2 are the concentrations at the beginning and end of the period we obtain
deltaT = 0.44*5.35*ln[(kE2 +Co)/(kE1 + Co)] (3).
Hence to solve for the temperature change between 1960 and 2008, we solve equation 2 using k as the reciprocal of 15 GTonnesCO2/ppm, Co as 290 ppm and E1 and E2 from the reference you use, Boden et al., as a cumulative 308 GTonnes in 1960 and 1272 GTonnes in 2008, giving
deltaT = 0.44*5.35*ln[(1272/15+290)/(308/15 + 290)]
giving
deltaT = 0.44*5.35*ln (375/311) = 0.44 C
which is in good agreement with the 0.47 C derived from the concentration figures for these two particular years. Your figure of 0.27 C is the result of you incorrectly relating emissions to concentration, giving a fallacious fixed “quantum of emissions necessary to raise global temperatures by 1K”. There is no such thing!
There is no contradiction between the warming derived from concentration and emissions, and certainly no independent constraint.
Again, I strongly suggest you ask your previous reviewers to take a closer look if you are still unsure as to your error here.
I suggest that Jim D, whoever he or she is. should do as I suggested earlier and look at what the IPCC actually says, rather than making up his own interpretation of it. Of the 2.8 K anthropogenic warming that it posits as a central estimate taken as the mean of all six emissions scenarios, 0.6 K is explicitly stated to be in-the-pipeline warming that results from our past sins of emission. The remainder is what arises by 2100 as a result of the CO2 we add to the atmosphere this century. Like it or not, that is what the IPCC says, and if you want to dispute it then take the matter up with the IPCC, and do not waste my time with your interpretations, which, however seemingly ingenious, are at odds with what the IPCC actually says.
Mr. House should really not waste any more time displaying his bottomless ignorance on this site, which allows all comers but expects at least a rudimentary level of knowledge. Evaporation, whether he likes it or not, is a negative feedback, as was inadvertently revealed by Wentz et al. (2007), when they demonstrated that the actual increase in evaporation from the surface per Kelvin of surface warming is thrice what the models say it is. And, this time, I do not expect Mr. House to reply until he has read and understood their paper. I am tired of giving him references that he then fails to follow up.
Professor Lindzen has calculated that this consideration alone requires the officially-published central estimates of climate sensitivity to be divided by three. Mr. House burbles, irrelevantly and trivially, that evaporation increases the water vapor concentration in the atmosphere, and that water vapor is a greenhouse gas. Yes, it is, but the process of evaporation (which takes place at the surface, as demanded by Mr. House) is nonetheless a negative feedback, and one which the models currently greatly undervalue, because they are unduly obsessed with radiative transports and do not give sufficient attention or weight to non-radiative transports within the atmosphere.
Mr. House tiresomely demands another example of a negative feedback, even though in my previous answer to his drivel I had already mentioned the lapse-rate feedback. If he is not prepared to read my answers carefully, he should not continue this discussion.
And, finally, he takes refuge in pathetic semantics, saying that when he had talked of “positive” feedbacks he had not meant “net-positive” feedbacks. Well, that point too is trivial: Since he disagrees – on no scientific or other rational basis that has yet been stated – with the long-established results in process engineering and in climatology demonstrating that negative feedbacks exist, all feedbacks in his world will of course be both positive and net-positive: in that disfiguring and scientifically absurd circumstance, the terms are self-evidently interchangeable.
I suggest that he should go and do some elementary reading in mathematics and in climatological physics before he tries – I fear deliberately – to muddy the waters any further. 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. I am willing – as previous postings here have amply demonstrated – to have a scientific discussion with those who are at least making a genuine attempt at discussing real science. Mr. House, however, starts from an absurd and scientifically-unwarrantable standpoint that there is no greenhouse effect, and – having thus abandoned the uses of reason a priori – is both temperamentally and educationally unequipped to conduct a rational, informed, logical scientific discussion. However, his interventions are perhaps of value in that they are yet further visible evidence of the sad level of general scientific and forensic ignorance that the climate extremists can and do so readily and ruthlessly exploit.
Christopher Monckton,
I should add you have misled yourself as to why you can ignore your admitted error.
You are right that you get away with it with regard to concentrations: this is because for a small relative change in concentrations between 1960 and 2008, from 317 to 386 ppm, the logarithmic relationship is close to linear for a change of around 20%, with only a 2% error. But this is not the case for emissions. They have increased from 308 to 1272 GTonnes, some 420%, and a linear approximation is off 65%. This is not a second order effect!
Monckton of Brenchley says:
September 1, 2012 at 3:56 pm:
“Evaporation, whether he likes it or not, is a negative feedback, as was inadvertently revealed by Wentz et al. (2007), when they demonstrated that the actual increase in evaporation from the surface per Kelvin of surface warming is thrice what the models say it is…. Mr. House burbles, irrelevantly and trivially, that evaporation increases the water vapor concentration in the atmosphere, and that water vapor is a greenhouse gas. Yes, it is, but the process of evaporation (which takes place at the surface, as demanded by Mr. House) is nonetheless a negative feedback,…”
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Christopher, first of all, certain properties of your rhetoric do not bother me directly, but they can easily damage your reputation among the readers, and this bothers me. Please consider sticking just to the scientific points and refraining from certain particularly inappropriate expressions.
MODELS??? Who is talking about models? You are essentially stuck on the possible lowest level: definitions and what immediately follows.
As I said before, the process of evaporation is releasing water vapour in the air. You mean it is a negative feedback? Prove it. You apparently know that there is such an effect as evaporative cooling. At the same time you accept the “greenhouse effect” that includes warming properties of water vapour. So, the process of evaporation allegedly contributes to both cooling and warming at the same time. And you mean that the net effect is cooling? Then prove it.
But OK, I am not going to “torture” you scientifically any further, you are already sitting in a scientific trap. Because if the net effect of the process of evaporation is COOLING, then the water vapour is not a greenhouse gas any longer per definition. If it is WARMING, then it is contrary to your statement not a negative feedback, it is then a positive feedback.
So, I suggest you acknowledge that and come up with another “negative feedback”. And please think twice before you bring that “lapse-rate” again.
I will just say that the pipeline (aka the ocean heat content excess) had a net gain in the 20th century.There is no expectation of a net loss in the 21st century. At least the same warming will still be in the pipeline in 2100. You can’t pay into the atmospheric budget from the pipeline, because at least as much leaks in the other direction as it was doing in the 20th century.
Greg House says:
September 1, 2012 at 3:19 pm
The alleged contradiction is not real, it is only the result of your possible misunderstanding, because you made “CO2-induced warming” out of my “greenhouse gases warming”.
Again, the “greenhouse gases warming” concept includes BOTH “CO2 induced warming” AND “water vapour induced warming”, and since “CO2 induced warming” produces more water vapour it produces thus also more “water vapour induced warming”, and this is a positive feedback.
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The subject of Monckton’s paper is climate sensitivity to CO2, which of course is the result of CO2 forcing plus the net balance of *all* feedbacks of either sign. An increase in water vapor is definitely one of the feedbacks that results from an increase in CO2 forcing, and it is a positive feedback. So what? Water vapor is itself the result of evaporation, which by itelf has a cooling effect. And water vapor results in more clouds, which also have a cooling effect. In any case, the water vapor that is a feedback of CO2 forcing cannot, by definition, be part of said CO2 forcing, which seems to be what you are claiming (to the extent it’s even possible to know what you are arguing about). Water vapor appears to be the only feedback you acknowledge from the CO2 forcing, to the point you want to make it part of the forcing itself, or at least declare it’s the only feedback worth considering.
Greg House says:
You apparently know that there is such an effect as evaporative cooling.
[…]
But OK, I am not going to “torture” you scientifically any further
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So first you question wether evaporation causes cooling and almost immediately you brag about torturing people “scientifically”. You have made an ass of yourself long enough and no one should reply to your brayings anymore.
[snip – rephrase that]
Greg House:”As I said before, the process of evaporation is releasing water vapour in the air. You mean it is a negative feedback? Prove it. You apparently know that there is such an effect as evaporative cooling. At the same time you accept the “greenhouse effect” that includes warming properties of water vapour. So, the process of evaporation allegedly contributes to both cooling and warming at the same time. And you mean that the net effect is cooling? Then prove it.”
Respectfully, you are confused here. It is not evaporation that is a positive GH feedback, it is the *presence* of water vapor. Ultimately, for the water cycle to be in balance, evaporation must equal precipitation but this, on its own does not establish what the concentration of WV is. For instance, the climate models usually predict that a 1C temperature increase will increase WV by ~6% but only increase evaporation by btw 1-3%. OTOH, the Wentz 2007 study referenced earlier suggests that the actual increase in evaporation is ~6% which implies a much higher negative feedback from evaporation following a temperature increase. IAC, see this link for more detail on the evaporation-lapse rate feedback.
http://stratus.astr.ucl.ac.be/textbook/chapter4_node7.html
Cheers, 🙂
Let me reply again to the various bizarre scientific points that are now being raised.
First, it is intellectually dishonest of “Tom P.”, who continues to lurk furtively behind a pseudonym, to say that I have admitted an error, when there was no error and, therefore, I did not admit one. Before I wrote the paper, I carried out careful calculations to satisfy myself that over the relevant period the relationship between changes in CO2 concentration and changes in temperature was very nearly linear because the climate-sensitivity parameter tended to grow with time, and that would offset the logarithmic decline in the forcing effectiveness of CO2.
Realizing this, “Tom P.” now shifts his ground and points out that CO2 emissions have increased fourfold over the period of study. So they have, but it remains true that the relation between the rate of change in emissions and the rate of change in concentration shows no trend over the period. Since the relation between the rate of change in concentration and the rate of change in temperature is also very nearly linear, for the reason I have just explained, it is legitimate for me to find the relation between the rate of change in emissions and the rate of change in temperature near-invariant over the short timescales concerned.
I repeat that if “Tom P.” wishes his argument to be taken seriously he or she must first reveal his or her identity and then carry out a quantitative analysis to demonstrate why he or she considers my analysis to be at fault. For mathematics is the language of science; equations are its grammar; and quantities are its vocabulary. If “Tom P.” continues to fail to deploy a quantitative analysis, then – scientifically speaking – he has nothing whatever to say.
Mr. House whines that he does not like me pointing out his ignorance. Then he should cease to display it. I had invited him to read Wentz et al., so that he could understand the implications of their finding that surface evaporation per Kelvin of surface warming increases at thrice the rate predicted by the models, but instead of reading it he asks me who is talking about models. The answer, as he would have known if he had read either my previous answer to him or Wentz’s paper, is of course Wentz. Shawnhet, another correspondent on this thread, has read and understood Wentz’s paper: is it really too much to ask that Mr. House should at least attempt to do the same? When (or if) Mr. House has read Wentz’s paper and understood it, let him come back here and discuss this matter further. If, however, he will not read the reference he is given, there is no point in answering him further on this aspect of the discussion. He appears not to understand that evaporation as a result of surface warming is a negative feedback; that an increase in atmospheric water vapor as a result of not only surface warming but, more importantly, of the warming of the space occupied by the atmosphere is a positive feedback in accordance with the Clausius-Clapeyron relation; but that, as Wentz’s paper and Shawnhet’s comment both helpfully point out, increased evaporation tends to be matched by increased precipitation.
Since my paper did not make any attempt quantitatively to disentangle the negative feedback from evaporation (which is thrice what the models thought) from the zero feedback caused by the additional water vapor in the atmosphere caused by the additional evaporation (for it simply precipitates out again), or from the positive feedback potentially caused by the increased Clausius-Clapeyron carrying capacity of the atmospheric space for water vapor as that space warms, his insistence that I now do so is off topic. He had asked me to identify any negative feedback, and I identified two of many: evaporative cooling, and the lapse-rate feedback.
Even if feedbacks are zero or somewhat net-negative, adding CO2 or any other greenhouse gas to the atmosphere will cause some warming, so Mr. House’s implication that because he infers that certain feedbacks may cancel each other out there is no such thing as a greenhouse effect is nonsense. Let him do some reading before he makes a still greater idiot of himself. He might usefully begin with the numerous references I have already given him. I have been very patient; but, as I have said, if he continues to argue aprioristically rather than logically and rationally he will make no useful contribution to the debate.
“Jim D.” equates the IPCC’s imagined (and, if my result is correct, imaginary) warming in the pipeline with what he calls an “excess” of ocean heat content. However, we remain unable to measure the heat content of the ocean reliably, so we have no idea whether there was a net gain in ocean heat content in the 20th century. Even the 3000+ Argo bathythermograph buoys, which since 2006 have been providing better coverage than ever before, are the equivalent of taking a single temperature and salinity profile at one location in the whole of Lake Superior less than once a year, as Willis Eschenbach pointed out in one of his distinguished contributions to this blog. Attempting to draw any conclusions from so sparse a sampling plainly has its limitations, to put it mildly.
Furthermore, in the IPCC’s speculative theory, warming in the pipeline comes chiefly not from some supposed (but not demonstrable) increase in ocean heat content but rather from the gradual coming into effect of long-acting temperature feedbacks (such as the supposed progressive loss of global ice cover and a consequent decrease in the Earth’s albedo).
However, his confusion on the matter of the warming in the pipeline is not so much his fault as that of the IPCC, which ought to have produced a curve of the change in the value of the climate-sensitivity parameter over time to allow direct verification of the extent to which the feedbacks it imagines (not one of which can be measured) are having the influence it imagines they will have. Yet the IPCC very deliberately does not do this. Indeed, it does not even quantify the zero-feedback or instantaneous value of the climate-sensitivity parameter until its Fourth Assessment Report, and only then in a footnote on p. 631. It provides no explicit statement of the centennial-scale, bicentennial-scale or equilibrium sensitivity parameters; however, as explained in the Annex, I have deduced their values as 0.44, 0.49, and 0.88 Kelvin per Watt per square meter respectively. From these values, it follows that most of the warming that is in the pipeline will not come out of it until long after the period of study, so the world will have millennia to adjust to it, and it need not concern us at all as policy-makers today.
Christopher Monckton,
You ask for a quantitative analysis: you have been given one in my comment of September 1, 2012 at 3:36 pm, clearly demonstrating that the data for concentration and emissions give the equivalent warming for the period 1960 to 2008 of 0.46 K and 0.44K.
Your value of 0.28 C is a result of your faulty analysis, evidenced by you calculating a “quantum of emissions” for a 1K warming. Such a constant quantum does not exist. You have admitted your error here, hoping it had no appreciable effect on your calculation over this period. For emissions, that hope is misplaced, as the numbers show.
There is no independent constraint on climate sensitivity available using the emissions rather than the concentration data. This should be hardly surprising given the linear relationship between the two.
I suggest you read the comment of September 1, 2012 at 3:36 pm , and if you still remain unclear as to your error, ask one of the scientists whom has seen your draft to go over it with you.
Unable to argue with what I actually wrote, the Viscount argues with its inverse.
I wrote that ‘reciprocal of the reciprocal of x is x’ i.e. 1/(1/x)=x
He claims I wrote that the ‘reciprocal of a quantity is equal to the quantity itself.’
Will the Viscount please apologise to the readers of this blog for misleading them.
Here we go again. Tom P still insists I have admitted to an error. No, I have not. I have merely indicated that an assertion of his is trivially true but does not cut athwart my analysis in any material respect. In the circumstances, it is intellectually dishonest of him to assert that I have admitted an error.
He then at last provides an argument with numbers in it: but all that argument does is to run my analysis backwards to its starting point and then to dismiss my argument on the ground that he has succeeded in reaching the starting-point. That is a novel instance of the argumentum ad petitionem principii – the begging-the-question fallacy.
My own argument starts from two simple observations that are derived directly from the data. First, that over this century the relationship between increases in CO2 concentration and projected increases in temperature is near-invariant, because the growth in the value of the climate-sensitivity parameter more or less exactly offsets the logarithmic diminution in the additional forciing that arises from each additional unit increase in CO2 concentration.
Let me demonstrate this quantitatively. Using the IPCC’s implicit climate-sensitivity parameter of 0.44 K/W/m2 for the whole of the 21st century, I have already established that one requires about 223 ppmv of additional CO2 concentration to generate 1 K of additional warming.
Now consider just the next four years, rather than the next 100 years. Here, because the time-frame is so short, a value for the climate-sensitivity parameter that is very close to the instantaneous value is appropriate: let us say 0.35 K/W/m2 rather than the instantaneous 0.31.
Then, taking the IPCC’s central estimates of CO2 concentrations over the next four years (derivable from Table 10.26 of the Fourth Assessment Report), warming over 2012-2015 inclusive would be 0.35[5.35 ln(402.6/392.5)] = 0.0476 K. Additional concentration per Kelvin of warming is then (402.6 – 392.5) / 0.0476 = 212.2 ppmv K–1. But this value is very close to the 223 ppmv/K calculated by the same method using the IPCC’s projections for the whole of the 21st century. That, I hope, establishes the near-invariance of the relation between CO2 concentration increase and temperature increase over the period of study.
But, as I think Tom P. accepts, over decadal to centennial timescales there is also a near-invariant relation between CO2 emissions increase and CO2 concentration increase.
Accordingly, little error arises if, over the period of study, we assume two constants: 15.5 Gte CO2 emissions increase per ppmv concentration increase; and about 220 ppmv CO2 concentration increase per Kelvin of temperature increase. Multiplying these two gives a third constant relevant to the period of study: namely the CO2 emissions increase per Kelvin of temperature increase. It cannot legitimately be said that the relation between CO2 emissions and temperature change is irrelevant, since that is precisely the point that everyone is arguing about.
Once the value of that constant is accepted, the rest of the argument follows. We know that there were 975 Gte CO2 emitted from 1960-2008, which is equivalent to 0.28 K, not to the 0.46 K that one would expect by applying the IPCC’s implicit 21st-century climate-sensitivity parameter to the period 1960-2008.
Mr. Oldberg wanders off topic by saying that equilibrium surface temperature is permanently unobservable. Whether it is or is not permanently unobservable, it is not currently observable, which is why, as I have had to point out to Mr. Oldberg twice before, my own analysis concentrated on the shorter-term sensitivity parameters whose effect is indeed currently observable, at least to some extent.
I must indeed apologize to Mr. Telford for having misread what he had written: on my screen his equation had indeed been mangled, as I had at first suspected, and I had not noted that he had used “the reciprocal of” twice in succession in his subsequent posting. His point appears to be that my argument is circular. But a careful read of my paper will indicate that this is not so. I begin by establishing the relation between the CO2 concentration increase and warming, deriving it from the IPCC’s own central estimate of 21st-century CO2 concentration increase and warming. Earlier in this posting, I have established that over the period of study this relation is near-invariant. I continue by independently establishing the near-invariant relation between CO2 emissions and CO2 concentration increase over the period of available data, which is 1960-2008. Multiplying these two near-invariant relations gives a new relation that is also near-invariant over the period we are concerned with: that of CO2 emissions and temperature change. It works out at about 3450 Gte CO2 per Kelvin.
Next, to find out how much of the 0.66 K observed warming from 1960-2008 was caused by CO2 emissions, I divide the measured emissions of 975 Gte CO2 over the period by 3450 Gte CO2, to yield 0.28 K, not the 0.46 K that the IPCC’s methods would lead us to expect. Finally, from this lower warming value, I derive a new and lower value of the climate-sensitivity parameter appropriate at centennial scale: namely, 0.27 K/W/m2, which, when applied to the 21st century, suggests that CO2-driven warming to 2100 will be less than 1 K. And that is it. It is quite straightforward and there is really no need to make such heavy weather of it.
Slioch continues to refuse to read the IPCC’s documents at the points I have previously referenced. If he want to argue with the IPCC’s 0.28 K of 21st-century warming, of which it states 0.6 K is already in the pipeline, then he should take the matter up not with me but with the IPCC. As I have already twice explained, the other end of the pipeline need not – and probably does not – occur within the next couple of hundred years, in which event it is simply not policy-relevant today. Slioch needs to learn that if he receives – as he has, on several occasions – a detailed answer to his assertions, then he must address those answers directly rather than childishly (and erroneously) repeating that I (or, rather, the IPCC) had made an error.
Slioch sneers that I am “apparently unable to recognise the conditional and illustrative nature of the derivation of the 0.75K per W/M^2 figure. Well, what he originally said was that that value was “in line with IPCC”. I had assumed that he had meant what he said, but I take it he now concedes he cannot find authority for this absurdly high value in the IPCC’s documents. He has, yet again, failed to take any note of my point that since the IPCC’s central estimate of the equilibrium-sensitivity parameter is 0.88 K/W/m2, and since equilibrium will not occur for 1000-3000 years (Solomon et al., 2009), suggesting a centennial-scale climate-sensitivity parameter that comes close to that value (and also exceeds by an absurd 50% the 0.49 K/W/m2 bicentennial parameter assumed by the IPCC for 1900-2100) is implausible in the extreme.
The climate extremists need to raise their game. Their arguments to date have been startlingly unmeritorious: but perhaps that is not unsurprising, now that 15 years without global warming has established a clear discrepancy between what the models had predicted and observed reality. Their central projections of future warming are indeed exaggerated, and it is becoming harder and harder – whether by the obfuscations and diversions we have seen here or by the publication of absurdly inaccurate IPCC reports – to conceal that fact.
Paolo says:
September 1, 2012 at 8:47 pm
“Greg House says:
You apparently know that there is such an effect as evaporative cooling.
[…]
But OK, I am not going to “torture” you scientifically any further”
So first you question wether evaporation causes cooling and almost immediately you brag about torturing people “scientifically”. You have made an ass of yourself long enough and no one should reply to your brayings anymore."
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Using your "[…]" nasty trick you certainly can let everything look like nonsense, well done.
Christopher Monckton,
It appears you did not take my advice to show your draft to a scientist who would be able to correct you on your analysis. At least your response should be making it clearer to others as to how you have confused yourself.
Your write:
“But, as I think Tom P. accepts, over decadal to centennial timescales there is also a near-invariant relation between CO2 emissions increase and CO2 concentration increase.
Accordingly, little error arises if, over the period of study, we assume two constants: 15.5 Gte CO2 emissions increase per ppmv concentration increase; and about 220 ppmv CO2 concentration increase per Kelvin of temperature increase. Multiplying these two gives a third constant relevant to the period of study: namely the CO2 emissions increase per Kelvin of temperature increase. It cannot legitimately be said that the relation between CO2 emissions and temperature change is irrelevant, since that is precisely the point that everyone is arguing about.”
The problem comes when you multiply the two constants together, as there is an offset in the emissions/concentration relationship. Hence while there is an approximate linear relationship between increase in concentration and increase in temperature between 1960 and 2008, and a very good linear relationship between emissions and concentration, though with an offset of around 300 ppm, there is not a linear relationship between emissions and the increase in temperature due to that offset.
Furthermore, while using a linear approximation for the logarithmic function for the small relative change in concentration, from 317 to 386 ppm, is justified, it is not valid for the large, non-linear change in cumulative emissions that have increased from 308 to 1272 MTonnes CO2 (equivalent to 86 to 346 MTonnes of C):
http://img850.imageshack.us/img850/9186/timeseries.png
The fault in your analysis in assuming a constant emissions per temperature rise is clear if you look at the emissions produced in the first and last decade of your period. As you state in your paper, you have taken the temperature as a linear trend over that period. Hence if there was a valid constant emissions per temperature, that would correspond to a similar quantity of emissions in the first and last decade.
In fact from 1960 to 1970, there were around 6 GTonnes of CO2 produced, while from 1998 to 2008 there were 11 GTonnes. Your data should have told you immediately that it was incorrect to base an analysis on a constant “quantum of emissions” for a given amount of warming.
At no point have I said that the relationship between CO2 emissions and temperature is irrelevant. What I have said is that you were incorrect to state that is has a constant value. It is the confusion in your maths that has caused you to get a different sensitivity using concentration and emissions.
It should now be clear that as both emissions and concentration give equivalent warming when properly calculated, there is no independent constraint on climate sensitivity emerging from you faulty analysis.
JimD said, “I will just say that the pipeline (aka the ocean heat content excess) had a net gain in the 20th century.There is no expectation of a net loss in the 21st century. At least the same warming will still be in the pipeline in 2100. You can’t pay into the atmospheric budget from the pipeline, because at least as much leaks in the other direction as it was doing in the 20th century.”
The oceans did have a net gain during the 20th century, mainly in the northern hemisphere where the majority of the warming took place. However, the the energy gained is just as likely due to recovery from ice age cooling which had a greater impact on the northern hemisphere than the southern. The thermal mass of the globe is not symmetrical, the solar forcing on the global is not symmetrical and the ocean heat uptake was not symmetrical. CO2 induced warming should be somewhat symmetrical.
JimD, most of you “beliefs” are based on linear assumptions made in a highly non-linear system. The data is there if you care to join the debate instead of repeating talking points.
http://redneckphysics.blogspot.com/2012/09/frame-of-reference.html
Once again you can avoid looking at what a simple change in reference can do to perspective, but there are significant flaws in AGW theory.
Shawnhet says:
September 1, 2012 at 10:46 pm:
Greg House:”As I said before, the process of evaporation is releasing water vapour in the air. You mean it is a negative feedback? Prove it. You apparently know that there is such an effect as evaporative cooling. At the same time you accept the “greenhouse effect” that includes warming properties of water vapour. So, the process of evaporation allegedly contributes to both cooling and warming at the same time. And you mean that the net effect is cooling? Then prove it.”
Respectfully, you are confused here. It is not evaporation that is a positive GH feedback, it is the *presence* of water vapor.
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I do not see any confusion. First of all, I did not say “it is evaporation that is a positive GH feedback”, so your “it is not evaporation that is a positive GH feedback” simply misses the point. The best way to avoid confusion is not to replace the opponent’s words with what you think he meant.
Again, the first essential point is that evaporation has (according to the AGW concept) at the same time 2 opposite effects: evaporative cooling effect and “greenhouse warming” effect. Any problem with that? Then the next step. Depending on the real numbers, the overall effect of evaporation can be cooling or warming. Any problem with that step? If no, then the next step.
As I said, if the the overall effect of evaporation is cooling, then water vapour is not a “greenhouse gas” per definition. If the the overall effect of evaporation is warming, then it is not a negative feedback, it is a positive feedback then.
Now, within the AGW concept water vapour IS a warming “greenhouse gas”, so you can not at the same time support that concept and maintain that the evaporation is a negative feedback. It is a clear contradiction and I hope that Christopher Monckton realises that sooner or later and drops it. If he hopes that warmists will not be able to see his contradiction, then it is a bad strategy.
“Jim Cripwell says:
August 31, 2012 at 3:50 am
I am an empiricist; I only trust hard, measured data. On the subject of radiative forcing and climate sensitivity, the only thing that can actually be measured is total climate sensitivity; how much do global temperatures rise as a result of a given rise in the amount of CO2 in the atmopshere. In theory we can measure total climate sensitivity. We can measure how much CO2 concentrations rise; we can measure how much atmospheric temperatures rise, assuming they are still rising. All we need to do is to prove how much of any observed temperature rise is due to the change in CO2 concentration.
What I cannot understand is why there is so little interest in making an attempt to actually measure total climate sensitivity. If we could actually measure it, it would be like a Michelson/Morley moment; it would settle whether CAGW exists for all time.
”
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It’s easy to ascertain the overall average sensitivity based on rather well accepted values. I’ve shown it on threads here before. It comes out to around 0.22 (0.218) K per W/m^2. That’s the average from the very first w/m^2 of atmospheric absorption from ghgs and clouds up to the most recent ones. Note that by the ipcc’s own words (a W/m^2 effect is assumed to be a W/m^2 effect regardless of what changes ) that a large variance between the average and the modern instantaneous sensitivity tends to falsify that hypothesis. Also, the 0.22 value does not include any feedback contributions from a slight rise in T which would bring it even closer to the 0.27 value mentioned by the author. The main feedback, h2o vapor, adds a tiny fraction of 0.22 to the total as a 5 deg C rise would be required to achieve a 30% increase in h2o vapor and it, like co2, is well into the log mode with between 2 and 3 times the power absorption per doubling as for a co2 doubling.
Note that a sensitivity of over 0.3 K / w/m^2 is necessary for surface T for a blackbody so any sensitivity less than that is indicative of a net negative feedback. That is, the positive feedbacks reduce the total net negative value a bit.
The problem with sensitivity is that co2 is a bit player while albedo, mostly due to cloud cover, is the main actor. There is no good history of albedo measurement data. You can find that most sensitivity research has ignored this as a variable and hence has created a nightmare of inaccuracy and over stated values. Also, it doesn’t help the Cagw case any.
As for M&M, it’s done a good job for a century but all theories need continual testing (and not just undergraduate students). After all, now we know the direction and speed Earth is traveling wrt the microwave background radiation as measured by WMAP which would be the velocity through the aether assuming it existed. LOL
Tom P.”The problem comes when you multiply the two constants together, as there is an offset in the emissions/concentration relationship. Hence while there is an approximate linear relationship between increase in concentration and increase in temperature between 1960 and 2008, and a very good linear relationship between emissions and concentration, though with an offset of around 300 ppm, there is not a linear relationship between emissions and the increase in temperature due to that offset.”
I must admit I don’t follow the disagreement that you and Mr Monckton are having or the reasoning behind using the emissions data at all(as separate from the concentration) but what you have written above isn’t accurate IMO. If we are talking about concentrations between 317 and 713 ppm, then establishing the relationship btw emissions and temperature change in the way MoncKton has done is perfectly reasonable IMO. Obviously the relationship btw CO2 and temp change is only approximately linear but this will only give you a slight difference in the calculations over the period in question.
BTW, what makes you think that there is an offset at about 300ppm anyway? I don’t see why there would be one.
Cheers, 🙂