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)
There is much conceptual confusion about the relation of the pipeline to the earth’s energy imbalance to the ocean heat content. I recommend Hansen’s 2011 energy imbalance paper for a clear and up-to-date exposition on the subject.
http://pubs.giss.nasa.gov/abs/ha06510a.html
Essentially, the radiative warming from CO2 is not immediately balanced by the increase in surface temperature as some goes into the deep ocean. This results in a radiative imbalance that continues to warm the earth and deep ocean until the surface temperature has risen to offset the CO2 effect. In reality it never catches up if the CO2 keeps increasing, leading to the energy imbalance being a semi-permanent state, and the pipeline warming in the ocean being a thermal inertia that delays the equilibrium until after the forcing has stopped changing.
The paper talks about the interplay of the aerosol effect and deep ocean mixing in controlling this energy imbalance, and how better measurements of the imbalance will help with separating these effects on the observed record.
Monckton of Brenchley:
In the article at http://wattsupwiththat.files.wordpress.com/2012/08/monckton_climate_sensitivity.pdf you state that “Warming delta T is simply delta F multiplied by some climate sensitivity parameter lambda.” In your comment of Sept. 1, 2012 at 1:55 pm, you state that “My paper did not, repeat not, depend upon the equilibrium sensitivity parameter.” From the content of the two statements, I gather that lambda does not reference the equilibrium climate sensitivity parameter but rather references a similar idea with the equilibrium temperature replaced by the actual temperature. Lamda, then, is the proportionality constant in a function that maps the change in the forcing to the change in the temperature. However, there can be no such function for in the period after a change in the forcing, the temperature is time varying.
Shawnhet,
The offset of a little less than 300 ppm, Co, is just the concentration of CO2 in the atmosphere, C, before there were any appreciable anthropogenic emissions, E, as expressed in my equation 2 above,
C = k E + Co (2).
Monckton has ignored this offset in his calculations, and hence miscalculated a different answer, 0.27 K, for the warming from emissions compared to the value he had calculated from concentration, 0.46 K. Rather than hearing a warning bell that maybe an error had crept in, Monckton posted this paper asserting that he had found an independent, and much lower, constraint for the climate sensitivity on the basis of the emissions data.
If the offset of equation 2 is included, I have shown that the warming from emissions over this period comes to 0.44 K, in close agreement to the 0.46 K value Monckton calculated from the increase in concentration.
Monckton set off to prove a lower constraint to climate sensitivity, but has ended up demonstrating a rather different constraint in his analytical methodology.
Tom P, it seems as though your issue here revolves around the following from the OP:”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).”
You appear to be arguing that it is impossible for the trend in two related phenomena to be the same if one trend starts at 300 units and another starts at 0. However, this is incorrect. If you have someone with $300 in the bank whose bank balance is increasing by way of a trend of $2 a year and someone with a bank balance of $0 but also with a trend of $2/year increase the ratio of the two is 1. You seem to be arguing in effect for the fact that the average balance in bank account 1 is greater than ave. bal in bank acct 2 which is true but does not address the point at issue.
Reality check here: the molecules of CO2 are the same whether you consider emissions separately or not. Regardless of whether we look at those number of molecules as being determined by a formula KE+Co or any other function, our calculated amount of warming should be same. I am sure that if we constructed a GH forcing function in terms of moles of CO2 we would probably have to include what you call an offset.
Cheers, 🙂
Shawnhet,
Your banking analogy nicely demonstrates where Monckton’s maths let him down. Both of the bank balances have the same growth, but you can’t calculate the ratio of the final amount to the initial amount over, say, five years by just knowing the amount that the balance has increased in that time. You need to know the starting balance for that.
Likewise, I certainly wouldn’t choose to put my money into an investment scheme based solely on how much money it would make me in a year. I would insist on also knowing what amount I had to invest in the first place! An annual return of $100 looks very good if I only have to put down $100, but lousy if $1m is required, although both investments are returning at the same rate of $100 a year.
Monckton tried to solve for the climate sensitivity using just the growth in emissions to calculate the temperature rise. But equation 1 requires the ratio between two numbers and to get that ratio from the emissions data requires the amounts at both the start and end of the period.
I would hope by now that Monckton realises his error. The independent constraint on climate sensitivity he has presented does not exist. It is just a result of his misunderstanding of how to do the calculation.
The global warming projections in the start of this thread.
How can they make these linear or accelerating when the effect of CO2 is logarithmic?
Those arguing whether evaporation is a negative feedback or not should remember that essentially all the water that evaporated subsequently condenses and precipitates. The latent heat absorbed during evaporation is released on precipitation, and there is no net cooling.
Reality gets slightly more complex as latent heat can be transported, cooling regions with net evaporation and warming regions where latent heat is released.
Let me explain again to “Tom P.” exactly what the calculation in my paper actually does. It is not possible to distinguish between the contributions to observed warming as between those from Nature and those from Man: all we know is that since 1960 the world has warmed by two-thirds of a Kelvin. However, it is possible to determine by looking forward to the next century how much CO2-driven warming the IPCC predicts; and, using that information, to determine the climate-sensitivity parameter that it implies.
Now, the c.s.p. curve is a slippery customer: the IPCC fails to make it explicit. However, it is possible to deduce, by the methods explained in the paper and particularly in the annex, that the instantaneous c.s.p. is 0.31 K/W/m2; that the centennial-scale c.s.p. is 0.44 K/W/m2; that the bicentennial-scale c.s.p. is 0.49 K/W/m2; and that the asymptote, which is the equilibrium c.s.p., is 0.88 K/W/m2. Broadly speaking, I should expect the evolution of the c.s.p. from forcing to equilibrium to follow the S-curve of an epidemic; and the best way to model it, as with modeling an epidemic, is to use matrix addition. However, these considerations are for another day.
The IPCC’s implicit estimated centennial-scale c.s.p. is determined in my paper by looking forward to 2100, using the IPCC’s own central estimates of CO2 concentration growth. You have agreed that the relation between CO2 concentration change and temperature change over the limited periods under consideration is near-invariant; so, applied during the 20th and 21st centuries, we may take it as constant.
Now for the relation between CO2 emissions change and CO2 concentration change. Here, my Fig. 1, derived by the methods and data set forth in Tables 1 to 5 of the Annex, agrees with original research by Dr. Patrick Michaels that shows a linear relation between the two. Notice that we are dealing not with CO2 concentration C, where the 300 ppmv offset that you mention would be relevant, but with CO2 concentration change delta-C. In this crucial respect, the route by which we reached today’s concentration is not relevant. It is for this reason that Shawnhet is correct in his conclusion that the offset is irrelevant: and his dollar analogy is apt.
I am not claiming a relation between emissions and concentration, but between the changes in each. Stand back for a moment and consider this. Surely it is not implausible to think – as the data strongly confirm – that there is a linear relationship between the change in emissions and the change in concentration? This is not a particularly surprising result: but it is certainly a result that has received insufficient attention since Dr. Michaels first discovered it. For, as I have demonstrated, it does indeed hold the key to providing a simple but robust check on the IPCC’s climate-sensitivity estimates.
The second point in your latest posting is that it is not reasonable to assume a linear relation between emissions growth and concentration growth from 1960-2008. I have not assumed it: I have determined it, using the actual data. And it is self-evident from Fig. 1 and from the full description of the data and methods by which it was determined that at no point was I assuming that temperature over that period had changed in a straight line. My sole reason for calculating the least-squares linear-regression trend on the data was to establish how much warming had occurred over the entire period. My calculations for Fig. 1 were, as stated in the paper and its annex, determined year by year on the data.
So there was nothing “faulty” in my analysis. An independent method of verifying the IPCC’s global-warming projections now indeed exists: and it demonstrates, not greatly to the surprise of most readers of this column, that climate sensitivity has been significantly overstated.
Tom P.’s interventions were based in what appears to have been a misunderstanding of what I had written. Here, I think, I am somewhat to blame. In trying to be brief I had become obscure. In the light of this and other comments, I shall be reworking the paper to improve its clarity and to expand the discussion at points where it is now too compressed for the scientifically-literate general reader. Once again, I am grateful to those whose contributions have assisted in clarifying the argument.
Friends:
At September 3, 2012 at 4:30 am Monckton of Brenchley writes
I rarely disagree with the noble Lord (except on matters of politics where we are poles apart) but, for the record, I write to say that I disagree each of his three points which I here quote.
Richard
”
Jim D says:
September 2, 2012 at 9:45 am
There is much conceptual confusion about the relation of the pipeline to the earth’s energy imbalance to the ocean heat content. I recommend Hansen’s 2011 energy imbalance paper for a clear and up-to-date exposition on the subject.
http://pubs.giss.nasa.gov/abs/ha06510a.html
Essentially, the radiative warming from CO2 is not immediately balanced by the increase in surface temperature as some goes into the deep ocean. This results in a radiative imbalance that continues to warm the earth and deep ocean until the surface temperature has risen to offset the CO2 effect. In reality it never catches up if the CO2 keeps increasing, leading to the energy imbalance being a semi-permanent state, and the pipeline warming in the ocean being a thermal inertia that delays the equilibrium until after the forcing has stopped changing.
The paper talks about the interplay of the aerosol effect and deep ocean mixing in controlling this energy imbalance, and how better measurements of the imbalance will help with separating these effects on the observed record.
”
**********
None of the IR makes it past the skin of the surface of the ocean. All of the energy is absorbed at the top small section and very little of it transfers by conduction downward. The only places where the ocean is moving surface water downward is in small areas of much colder climate – not where there is substantial incoming solar and higher atmospheric temperatures near the surface. Have you ever tried to boil a pan of water by placing a hotplate upside down on the top? All of the mechanisms that make it straight forward and easy to boil water sitting in a pan on top of the hotplate are now working against the attempt. The same goes for the vast amount of oceans.
Visible light, almost 50% of total incoming solar, penetrates the surface to significant depths, some beyond a few hundred feet. LW IR emitted by atmospheric temperatures doesn’t get past the skin, well under an inch. It results in increased evaporation. Water vapor is a lighter molecule, 18, vs the average of 28.8. Like helium, it will rise, absorbing more IR energy and reducing its density even more (like a hot air balloon rises). It will rise until the water vapor is forced to become liquid/solid as the RH rises with decreasing T. At that point, the heat of evaporation absorbed by the water at the surface will be given up, well above most ghg effects and well above the surface.
My experience with reading hansen papers is that if he says it, it’s most likely wrong or totally unsupported by the facts presented.
Christopher Monckton,
You write “Surely it is not implausible to think – as the data strongly confirm – that there is a linear relationship between the change in emissions and the change in concentration? This is not a particularly surprising result: but it is certainly a result that has received insufficient attention since Dr. Michaels first discovered it.”
It is a little odd that you pretend I dispute this relationship. I even plotted it for you two days ago: http://imageshack.us/photo/my-images/703/emissionsvsconc.png/
In fact the fatal flaw in your paper, and one you appear to be blind to, is that you cannot determine a change in temperature from equation 1 from a single value for the growth in emissions from 1960 to 2008. You should really have suspected an error as soon as you calculated a result for the degree of warming from emissions that differed from the value derived from concentration.
And if Dr. Michaels presented his research as original, you have been rather misled. The linear relationship between CO2 concentration and emissions was well know more than two decades ago. The first IPCC report in 1990 states: “the observed rate of CO2 increase closely parallels the the accumulated emissions trends from fossil fuel combustion and land use changes” (IPPC 1, Chapter 1 p 14). In fact it was highlighted in IPPC 1 as evidence for an anthropogenic source of the measured change in the CO2 in the atmosphere.
You appear to have reinvented the wheel, but this time as square. I agree, a little rework of the paper would be a good idea.
rgbatduke says: “…a certain amount of absurdity, e.g. spending 40 years making a journey that is at most a few weeks on foot today.”
RGB-san: If you are going to get Biblical on us (and I’d just as soon that you didn’t), you should keep in mind that the Arabic word for “forty,” Arba’een ( الأربعين ), is also used for “many.” In the manner of most things in that region, as it was then, it is today, and vice versa. When the Bible says, for example, that Jesus fasted for forty days and forty nights, it means that he did so for a long time, not a literal 40. There are those that believe otherwise, but the less said about them, the better.
TomP: I checked your linked graphs, thank you, and noted that 1) the range of CO2 concentrations is fairly narrow, (316 to 383 ppm), representing a short time span. 2) CO2 concentrations vs time are highly autocorrelated. 3) anthropogenic emissions are also highly autocorrelated over time. Furthermore, 4) the CO2 cycle is very complex and not well understood. 5) there is no rigorous proof of causation between anthropogenic emissions and total CO2 concentrations. Studies using two such highly autocorrelated variables often result in conclusions akin to “global warming is caused by pirates.” I think that is what you’ve done here, Matey.
Greg House says: “The concept of “greenhouse gases warming” excludes [this word changes meaning herein!] a negative feedback [so you claim]. You can not have both at the same time. [yes you can] If the concept of “greenhouse gases warming” is correct [it isn’t], then you generally must have more warming if you have more “greenhouse gases” (until the effect is saturated). If warming increases concentration of water vapour in the air and water vapour is a “greenhouse gas”, then you will inevitably get more warming, this is a positive feedback. Logically, if there is a proven negative feedback, then it proves the concept of “greenhouse gases warming” to be false. But, as I said, you can not have both at the same time.”
Faulty premises + circular reasoning + equivocation = invalid conclusions.
cba, the net effect of IR at the surface is cooling. This is also good for mixing. The only thing downward IR does is reduce the cooling rate, and the ocean stays warmer that way.
Tom P:”Your banking analogy nicely demonstrates where Monckton’s maths let him down. Both of the bank balances have the same growth, but you can’t calculate the ratio of the final amount to the initial amount over, say, five years by just knowing the amount that the balance has increased in that time. You need to know the starting balance for that.”
I agree with what you have posted here and not having gone through the calculations myself, I am willing to assume that you have the correct context for them. I thought the point at issue is whether the ratio of conc. increase(or change in concentration) to emissions is (more or less) constant but I may well be mistaken. I can agree (as you state later on) that if the two methods of calculating temp change (using emissions and concentrations) give substantially different answers, then one of them(at least 😉 ) must be wrong.
richard telford says:
September 3, 2012 at 3:24 am
Respectfully, this post is mistaken. You are correct that all evaporation is balanced by condensation but what you have missed is where these two processes take place. Evaporation takes place at the surface and condensation takes place overwhelmingly in the atmosphere. This has the effect of moving heat higher up into the atmosphere where it is more easily emitted to space.
Cheers, 🙂
The greenhouse effect is simply to prevent it getting to warm during day with sunlight and getting cold when there is no sunlight?
”
Jim D says:
September 3, 2012 at 9:46 am
cba, the net effect of IR at the surface is cooling. This is also good for mixing. The only thing downward IR does is reduce the cooling rate, and the ocean stays warmer that way.
”
not if the net result is to generate more h2o vapor and more clouds.
I shall go with Dr. Courtney, whose identity and expertise are known to me, and not with Tom P, who continues to lurk behind a mere pseudonym and appears to have some difficulty with elementary logic. The reason why my calculations differ from those of the IPCC is that I have determined the IPCC’s implicit linear relationship between CO2 concentration change and temperature change from its predictions of both over the 21st century (for it cannot be determined from observation), and I have determined the relationship between CO2 emissions growth and CO2 concentration growth from the period 1960-2008, because it can be determined from observation. My purpose in introducing emissions per Kelvin of warming to the calculation is that, for the first time, it allows a respectable determination of the fraction of observed warming that is attributable solely to CO2, from which a tolerably reliable determination of climate sensitivity also becomes possible.
Since both of these relationships – CO2 emissions change vs. concentration change and concentration change vs. temperature change – are near-invariant over relevant timescales, I may legitimately regard them as constants over the period of study without significant error. Therefore, I may – again, legitimately – take their product and use it to establish the results in my paper.
I do not obtain different results by the use of emissions and by the use of concentrations, for the blindingly obvious reason that I use both in the calculation. The reason why I have obtained a result different from that of the IPCC is that the IPCC has exaggerated climate sensitivity over the period of study.
One understands that Tom P. and many others who have commented here have passionate, aprioristic beliefs that my result calls greatly into question: but science is not done by overruling the data aprioristically: it is done by rational and logical examination of the evidence. That is what I have tried to do here, and none of the arguments advanced thus far call the result credibly into question.
Christopher Monckton,
You now claim “I do not obtain different results by the use of emissions and by the use of concentrations”.
When you first solve for the warming in equation 1 using just the concentration values of 316.9 ppm in 1960 and 385.6 ppm in 2008, you correctly obtain a value of 0.46 K. However, when you use the well derived linear relationship between concentration and emissions to recalculate the warming, you obtain “by the present method” a value of 0.28 K.
This you claim gives an independent constraint on a lower climate sensitivity. But your “present method” is plainly wrong, as it only uses the growth in emissions between the two dates. As I have clearly shown in my comment of September 1, 2012 at 3:36 pm, correctly rewriting equation 1 in terms of the emissions values gives a value of 0.44 K, not 0.28 K.
But apparently you now believe 0.28K is no different from 0.46K.
You have not only reinvented the wheel as square. You are now insistent that despite everyone seeing that your wheel clearly has four sides, it is still in fact a circle.
Tom P:
I offer you two pieces of sincere and friendly advice.
1.
When you are in a hole then stop digging.
2.
It is better to be thought a fool than to say things which prove you are a fool.
Richard
[Snip. ‘Denialism’ or its synonyms violates site Policy. ~dbs, mod.]
Quite a lot of arguments about simple facts, let’s repeat some:
Carbon emissions are the product of human activity: that are added on the top of natural emissions (which are probably reversible and stay in check with the natural sinks). Before the industrial age it is assumed that the CO2 concentration was more or less constant at about 280 ppm.
Two diagrams show both carbon emissions and CO2 concentration, in absolute terms and in annual increases. See : http://db.tt/xRXF52CI and http://db.tt/xfOIcSnV
Not all emitted CO2 stays in the atmosphere: calculated over the past 260 years the balance indicates that about 1/3 was absorbed to form of biomass or carbonate sediments, and 2/3 remained in the atmosphere (a slight accumulation as diluted gas in the ocean contributes to some acidification; ultimately this also goes to biomass and sediments). See: http://db.tt/unQGb4LZ
For each billion tons carbon emitted you can expect a CO2 concentration increase of 0.46 ppm.
In 2010 the emissions were 9.1 billion tons (CDIAC), therefore we could have expected the atmospheric CO2 concentration to increase by 4.2 ppm, but it was only 2.4 ppm (there is a time lag to take into account, but this pattern repeats itself every year).
Then you can argue about temperaure sensitivity: forcing as a result of atmospheric CO2 concentration change, a logarithmic dependency:
ΔF = 5.35 · ln(2) = 3.7 W m-2 for each doubling of CO2.
Since the beginning of industrial age: ΔF = 5.35 · ln(391/280 )= 1.79 W m-2 .
Depending on the model used (a linerization is allowed if changes are small) this means that the Earth surface temperature should have increased by approx. 0.37 °C just because of carbon emissions.
Then comes the system feedback to this primary forcing: as it is a net negative one, the temperature increase will remain at a lower level. Depending on the model and parameters used this may be approx. 0.29 °C (see model example: http://db.tt/BQuIQDyu).
Or for any doubling of CO2 concentration we could expect an increase of approx 0.6 °C.
These figures are much more modest than the dire predictions of any IPCC scenario. This is the important conclusion.
All other changes must be linked to other causes; but this cause (anthropogenic carbon emissions) cannot be dismissed as deniers do.
my earlier comment: sorry! the link for CO2 balance is http://db.tt/eMimzA71
Richard Courtney,
Apologies, I obviously overgeneralised when I said that everyone can see that Monckton’s reinvented wheel is square. You are clearly an exception.
I suggest you go carefully through my post of September 1, 2012 at 3:36 pm to see why the emissions data gives a warming of 0.44 K, not Monckton’s incorrect value of 0.28 K. Let me know if you have any difficulty following it.