From the "what were they thinking" department…
The "Physics and Society" Forum of the American Physical Society decided to open up their newsletter to a nice respectful debate on the main conclusion of the IPCC: that "anthropogenic CO2 emissions are very probably likely to be primarily responsible for the global warming that has occurred since the Industrial Revolution". From there, things went downhill quickly!
Two articles appear in the forum's July 2008 newsletter. The "pro" case is A Tutorial on the Basic Physics of Climate Change, by David Hafemeister & Peter Schwartz. The "con" case is Climate Sensitivity Reconsidered, by Christopher Monckton.
Monckton is rather … notorious … for those who follow these debates; and an extraordinary choice for a physics journal. His article has lots of formulae but little insight or competence. It did not take long for things to turn ugly.
In short order, half the blogsphere fell over themselves in triumph that the APS had reversed its long standing recognition of the facts of anthropogenic global warming; and gleefully concluded that the APS with its 50,000 strong membership could now be added to the ranks of the denialists. Fulsome praise was heaped upon Monckton's article as a brilliant mathematical refutation of the IPCC conclusions. It did not take long for the APS to add to its front page a plain statement that there had been no reversal of position; and add in red ink to the top of Monckton's article a notice that it had not been subject to scientific peer review, and drew conclusions that were in "disagreement with the overwhelming opinion of the world scientific community" and with the Council of the American Physical Society. Monckton hit back immediately with a letter demanding an apology and retraction.
How this all plays out will be most interesting to follow. The initial decision by the APS editor was extraordinarily naïve. I don't know what they expected to achieve with this; but whatever happens now it's a big win for Monckton and his fans. He's got a pulpit, and any response will be dismissed as scientific close-mindedness. Treating it as a serious debate is all that the denialists really want to achieve. Firing the editor (as some have suggested) is surely an over-reaction that would only make everything even worse.
Hey ho. I'm going to watch the social developments with interest; and attempt a minor contribution of my own just to indicate some of the errors, in my opinion, in Monckton's article.
There are, by the way, bound to be errors in my analysis as well. I'm posting it because I'll welcome feedback or corrections -- from anyone -- and because I think it is much better to focus on the substance of article, now that it has been published. I'm not an expert, but I co-incidently was reading many of the relevant papers used also by Monckton just recently, and so am willing to risk this attempt at analysis.
Basically, Monckton looks at the matter of "climate sensitivity" and feedbacks. For a useful review paper on the background to this topic, I recommend How Well Do We Understand and Evaluate Climate Change Feedback Processes? by Sandrine Bony and thirteen other authors; in Journal of Climate, vol. 19, issue 15, pp 3445-3482. (37 pages) You can also get a preprint by ftp from University of Washington Earth Observing System. It comes with a very handy little appendix to explain how climate feedbacks are quantified. Monckton also refers to this extensively.
I'll skip down to Monckton's attempt to use "The IPCC’s method of evaluating climate sensitivity".Part 1. An attempt to use the IPCC's method
It starts out ok. There is a formula used for the temperature change that should be expected for a doubling of the concentration of CO2. It is:
ΔTλ = ΔF2x κ f
The variables here, using Monckton's naming conventions, are
Monckton then correctly notes (eqn 3) that ΔF2x is about 3.7 W/m2. This follows from some basic physics, albeit obtained with difficult integrations across the spectrum and along the atmospheric column.
Everything from this point goes rather pear shaped. He makes a completely different use of the variable, to represent some kind of total anthropogenic forcing associated with a CO2 doubling, using a rather confused set of extrapolations from other effects. Basically, he takes the 3.7, scales it up so that it stands for 75% of a total forcing from other greenhouse gases, subtracts a fixed amount for aerosol cooling, and finally applies a "probability-density function" correction which has me baffled. The probability density functions for combined 1750-2005 forcings are in figure 2.20 of IPCC 4ar; It looks a bit like Monckton has taken the mode of 1.72 for the distributions by adding up best estimates for each individual forcing, and then scaled to get the mean 1.6 of the combined distribution (which is a bit skew) as given in section 2.9.2 of IPCC 4ar. Anyhow, after all of that weirdness, he ends up with about 3.4 as a forcing value; which is no longer a doubling of CO2 forcing but a strange kind of combined forcing not properly associated with any meaningful bench mark.
However, it is a forcing; so let's see what he does with it next.
His value of κ as 0.313 K W-1 m2 is uncontroversial. See the reference to Bony et al (2006) I link above.
The feedback multiplier contains more weirdness. Monckton includes a 0.25 "CO2 feedback", which is actually about the changing rate at which carbon is taken up from the atmosphere into the other reservoirs of the carbon cycle. This is discussed in section 7.3.5 of IPCC 4AR. What it means is that the fraction of emissions removed from the atmosphere reduces as carbon is being taken up and as temperatures increase; so that the same level of emissions results in a greater CO2 concentration.
This is not a feedback in terms of more temperature per unit forcing, and should not treated as such. Adding the 0.25 term is an error here, and it becomes very obvious as an error later in Monckton's article.
In any case, Monckton gets 2.16. He'd have been better to stick with 1.9; which is the actual feedback parameter. The accuracy of this number is low; certainly not enough to justify two decimal places.
The gain is then obtained as (1-2.16*0.313)-1, which is 3.077; far too many figures of accuracy. The errors in the 2.16, combined with the subtraction, mean that this number is only accurate to about +/- 1
Also, it should be (1 - 1.9*0.313)-1, which is more like 2.5.
Finally, he multiplies everything together to obtain 3.405 x 0.313 x 3.077 ≈ 3.28. Using the correct numbers, this would be 3.7 x 0.313 x 2.5 ≈ 2.9.
Monckton congratulates himself for "demonstrating that the IPCC’s method has been faithfully replicated" because his value of 3.28 is close to the central point of the range offered by the IPCC, being from 2 to 4.5.
However, what the IPCC actually says (technical summary) is:
So in fact, if Monckton had simply used the 3.7 forcing and the correct feedback parameter of 1.9, he'd have got much closer to the IPCC conclusion, and would have been following their methods.
So far, the errors don't have a lot of impact, but they demonstrate a level of basic misunderstanding that does not bode well. From here, things go downhill fast.Part 2.1 Adjusting the numbers. The forcing.
The first and major step is a look at radiosonde data for warming in the troposphere. This is a notoriously difficult area, as the radiosonde record has well known systematic errors, which have been discussed now for decades. A couple of recent papers have come out just this year which address many of the issues by using wind shear information. Specifically:
Basically, the mid-troposphere warming is indeed present, as expected.
Monckton does cite this new research, but dismisses it on the basis of satellite records... another case where measurement and calibration errors are a source of hot dispute. In any case, let it go... because what Monckton does with this is astounding.
He divides the forcing by 3. (equation 17)
That's just surreal. There's no basis to reduce the forcing here. It's the temperature response that is involved. He gives a vague appeal to Lindzen (2007), Taking greenhouse warming seriously, in Energy & Environment 18 (7-8). But that paper does not propose any reducing in forcing; only to sensitivity... on roughly the same dubious basis of limited troposphere warming.Part 2.2 Adjusting the numbers. The no-feedback sensitivity.
Here I confess to sharing a concern with Monckton. I've been looking at these papers now for a couple of months now for another discussion, and I also have tripped up on how this parameter is defined. I've been reading the same references Monckton gave in his paper (Soden, Bony, Colman etc) and I don't really get how the value of -3.2 is obtained. I can understand the -3.7. If anyone reading this would put a comment or a pointer to help clarify, I'd appreciate it!
But in any case. For this next calculation it become obvious that including the carbon dioxide feedback term of 0.25 as part of the feedback parameter b was an error. Monckton uses his 2.16 feedback parameter for a fixed CO2 forcing taken from observations. But that 2.16 included the curious 0.25 addition intended to account for changes in how carbon is taken up into the carbon cycle. It definitely can't apply here, where direct measurement of CO2 levels are being used.
There is also the bizarre use of a "mean" between two totally conflicting sets of measurements; based on NCDC, and a rather strange halving credited to McKitrick. It should be two alternative values; not a mean. And by using 1.9 rather than 2.16, you should get about 0.31 from NCDC values and 0.22 from the halved temperature.
This is not a sensible way to estimate κ, but in fact using the NCDC it gets close to the original value being used. But now Monckton is "double" dipping, in diverting the number down based on McKitrick... because this is ANOTHER reference to reduced warming trends... already used above to reduce the forcing estimate.
(Hat tip also to Tim Lambert, who notes this same error at the Deltoid blog: Monckton's Triple Counting.)Part 2.3 Adjusting the numbers. The feedback gain.
Monckton looks immediately to maximum upper bounds here; which conceals another subtle error. The various feedback parameters are not independent of each other.
In particular, the magnitude of a water vapour feedback (positive) tends to track with the magnitude of the lapse rate feedback (negative), since both become stronger with more water vapour in the atmosphere. Water both has a greenhouse effect for a positive feedback, and a weaker lapse rate for a negative feedback. You can't maximize both together; their sum shows less variation than either one by itself.
The actual range of all feedbacks together is available in Bony et al: it is about 1.5 to 2.6
There's no problem with the maximum exceeding the 1/κ value of 3.2
There's also a curious point that Monckton has already proposed a lower value for κ, which raises 1/κ to a bit over 4; but that is a detail. The fundamental error here is in simply adding up the upper bounds of feedbacks. They are not independent values; but are obtained as tuples from a range of models. Details in Bony et al (2006).Part 3. Conclusion
Monckton's paper looks superficially impressive, but examination of the equations betrays some fundamental confusion on the physics and climate science involved.
Monckton's best case here is simply the alleged lack of mid-troposphere warming. All the maths stuff is so badly flawed that it detracts from the shreds of what argument might be salvaged. The issue of troposphere warming will continue to be a focus of interest and debate; but skeptics invariably fail to take proper account of the large error bars on the old troposphere temperatures they invoke; and with the recent work on wind shear this argument, which was never strong, is looking more and more dubious.
Update: (July 26) Gavin Schmidt at realclimate has a response as well: Once more unto the bray. Gavin, by the way, is the real thing; a scientist active in climatology, and in public communication efforts, and with a daunting record of directly relevant formal scientific publication. He also linked to my little blog! Me and Gavin, yeah, that's the ticket.
Sunday, 20 July 2008
The APS and global warming: What were they thinking?
Analysis of models together with constraints from observations suggest that the equilibrium climate sensitivity is likely to be in the range 2°C to 4.5°C, with a best estimate value of about 3°C.
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Feel free to use or cannibalize my Figure 7 discussion. I think it's important since over the years that graphic (produced, interestingly enough, by the State of West Virgnia's chief mining engineer) has impressed lots of people as constituting a strong prima facie case against CO2 as a major factor in climate. (Whether it really did impress Saperstein or not is an interesting question. On the face of things yes, but I suppose another interpretation would be that he was saying "More rope, Your Lordship?")
ReplyDeleteHi Steve; welcome and thanks for the comment.
ReplyDeleteHere's a link to the discussion as you provided in a comment in the Deltoid blog: comment by Steve Bloom on paleorecords of CO2 and temperature in Monckton's paper.
Just to note that the FPS in the recent past did not find it so difficult to deal with climate-related articles "outside of the consensus".
ReplyDeleteFor an example, see Gerald E. Marsh’s “Climate Stability and Policy” in April 2008.
According to Marsh, current CO2 levels are too low and contributing to climate instability, even 750ppmv could still be not enough to stop an upcoming, catastrophic Ice Age. and the IPCC should switch its focus towards “determining the optimal range of carbon dioxide concentrations that will stabilize the climate, and extend the current interglacial period indefinitely”.
There was no major controversy at the time, even if the above is not mainstream at all.
Why did the APS had to overreact about Monckton with red inks and a rebuke of the FPS editor, I do not understand. Couldn't they simply publish a point-by-point rebuttal in next issue of the FPS? Especially if to write such a rebuttal only a couple of days are needed.
Welcome omniclimate!
ReplyDeleteI think the reason a disclaimer was needed on this occasion was simply that there was such an immediate and widespread distortion of what had occurred.
Specifically, it was immediately being claimed all over the blogsphere that the APS was reversing its position, and that Monckton's article was peer reviewed, or that Monckton's article being published meant some kind of endorsement.
All the above are false; and it was quite appropriate to put up an immediate and plain statement to counter these misrepresentations and set the matter straight.
The same could have been said for Marsh's article; but I don't there was a need, since it should be obvious anyway and it was not being widely misrepresented in the same way, I think.
In my view, we definitely don't want to insist everyone must march with the mainstream. But not all maverick ideas as poorly thought out and incoherent as Monckton's article.
Marsh's article; though idiosyncratic and well outside conventional notions, and with flaws of its own, is still more competent and interesting; and was not so swiftly misrepresented all over the internet.
Why did the APS had to overreact about Monckton with red inks and a rebuke of the FPS editor, I do not understand.
ReplyDeletePerhaps because Monckton issued a press release (through an organization for which he serves as policy maestro) claiming that the APS had published his "major PEER-REVIEWED scientific paper mathematically disproving AGW in an APS JOURNAL".
Two false statements bolded there ... (it's a newsletter, not a journal as typically understood by scientists and as implied by Monckton).
Monckton's been feeding the denialsphere response with false statements. It's no overreaction to attempt to set the record straight, though it's already far too late.
In the case you cited, did the author misrepresent his work and lie about the APS ("reversal of position" crap)?
"Monckton's been feeding the denialsphere response with false statements. It's no overreaction to attempt to set the record straight, though it's already far too late.
ReplyDeleteIn the case you cited, did the author misrepresent his work and lie about the APS ("reversal of position" crap)?"
I still can't understand. Surely the whole point of a 'debate' is that you are prepared to change your position, assuming the argument is good enough?
I can see that Monckton's paper has errors - why not point these out? Instead the APS seems to be suggesting that they are having a debate, but have decided beforehand that they will NOT change their minds! In which case, why have the debate at all?
has anybody got a link to Monckton's organization "press release"?
ReplyDeleteThe first press release of which I am aware came from the Society & Public Policy Institute, on July 15, signed by Robert Ferguson, who is the society's president. Monckton is the "Chief Policy Advisor", so he is almost certainly the source of the information. The release describes Monckton's article as a "mathematical proof" in a "major, peer-reviewed paper", within a "learned journal". It apparently came out on the day the newsletter was released; at least, it speaks of "today".
ReplyDeleteSee Proved: There is no climate crisis.
Hi,
ReplyDeleteI tried my own hand at Monckton's numbers and I am not sure of what I am doing, but I think I found something weird.
IPCC gives the forward 'gain'k as
.313 C-m^2/W
and the backward 'gain'b of 2.16 W/m^2-C.
I write the loop equation recursively (.313)*(F+2.16(Tn-1)previous temp)=Tn.
Notice the +. That's because the feedbacks are positive and adds with the F. I use F=5.358*ln(C/278) for the forcing function.
Try it at 550ppm and I end up with a temperature rise of 3.5 degrees C
for the IPCC values above. Monckton quotes Hansen as reporting a temperature rise of 2-4.5 deg C with an average of 3C at 550 ppm.
Then put in Monckton's 'corrected' values of k=.241 and b=3.38 and I get a much higher number of 4.69C at 550 ppm. This is because Monckton (stupidly) INCREASED POSITIVE feedback effects from 2.16to 3.38.
In other words his 'improved' method shows much greater warming. I also tried it at 378 ppm and he is slightly higher at 1.69C than Hansen at 1.68 deg C.
I might have screwed this up but I don't think Monckton realizes that the backward loop is for a positive feedback situation(i.e. water vapor, other GHG are increase temperatures).
He was so proud of his algebraic gyrations I don't think he checked his own sums, IMO. It's also irritating that he uses K instead of C because 3.5 degrees K is incredibly cold. He also uses 338ppm as a baseline Co, but also 278 ppm
Comments?
Hi anonymous. A few trivial terminological comments.
ReplyDeleteNormal conventions in science are to measure temperature in Kelvin (K). I'll be doing that. Note that a change of temperature in Kelvin is the same as the change in degrees Celcius. Hence 3.5 K is not a "cold temperature", but a "small change in temperature", and it's the same whether in Kelvin or Celcius.
Careful of the term "gain". Gain generally refers to the dimensionless factor by which a signal increases or damps. In this case, "f" is a "gain" due to feedbacks.
The value κ is a "sensitivity" term, given as 0.313 K/(W/m^2). It is also often inverted, and indeed Monckton obtained 0.313 by inverting the 3.2 W/m^2/K provided in his references; also called the Planck feedback parameter or the Plank response, or blackbody response, or variations of such terms.
The value b is also a "sensitivity" term, for feedback. The actual "gain" is factor by by which sensitivity increases as a result of feedback, which is 1/(1 - bκ).
This gain is actually the solution to your recurrence relation for temperature. Just calculate Tinf = 0.313 * F * gain
I think you have misunderstood Monckton's argument (which is not as clear as one might like!)
Monckton reasons as follows:
1. The IPCC uses a feedback value of 2.16.
2. The IPCC uses a base response of 0.313
3. The product of these must be less then 1, or else there would be a runaway feedback, which we obviously don't have.
4. The feedback value is uncertain, with an upper bound of 3.38
5. The product of 0.313 and 3.38 is more than 1.
6. Clearly then, the upper bound is too high, and should be reduced.
7. If we are justified in reducing the upper bound, we should also reduce the central estimate.
8. Ergo; the feedback value should be less than 2.16
Clear as mud? The whole foundation of Monckton's artgument is that feedback estimate is too high, and should be reduced. Here is the big error in Monckton's chain of reasoning.
1. Actually, the IPCC uses 1.9
4. Actually, the upper bound on this value is 2.6. The simple sum of upper bounds on the individual parts of the feedback is invalid.
5. The product of 2.6 and 0.313 is less than one, so there's no problem here about feedbacks being too large.
Different baselines for CO2 are fine; it just depends on what times you are looking at. For estimating sensitivities, it's actually much better to take a more recent baseline, because if you go all the way back to he pre-industrial value there are too many other forcing factors to mess things around.
His sums are more or less okay. It is the analysis and the physics that is really incompetent.
Hi DQ,
ReplyDeleteYes, I did notice that k*b HAS to be less than 1, but I was using
his 'improved' values to show that while at lower ppm Monckton produces less temperature, at ppms larger than 378 the temperature rise is even greater than Hansen calculates. I suppose I am assuming that his new values are sincere(and wrong) and you believe they are simply bogus.
You say his sums are right but what do you get for a temperature rise over 278 ppm at 550 ppm using his formula?
Monckton quotes Hansen saying 2-4.5,averaging 3 degree rise over all, and I get 3.5 degrees using the formula and IPCC k=.313,b=2.16.
Using Monckton's k=.241,b=3.38, I get 4.6 degrees at 550 ppm.
I am interested in this because the paleological time chart Monckton shows, indicates that the average of the earths temperature 1750 was ~12 C and in the Cretaceous it was ~22 C and I believe Al Gore said recently that CO2 concentrations soon shall be as high as they were 60 million years ago at the end of the Cretaceous(~1000 ppm).
Using the formula and k=.313, b=2.16 I get a temp rise of 6.6C but with Monckton k=.241,b=3.38 I get
8.8C which is close to 10C in the chart.
Is it worth checking? (I used an excel spreadsheet.)
You are not following his argument still. Check my comment #10 again.
ReplyDeleteIf you still don't get it I'll try again; but fundamentally Monckton is NOT suggesting 3.38 as an "improved value" for b; precisely the reverse!
His argument is wrong, of course. But your criticism of it is off target as well. Read through my comment #10, especially the 8 step argument proposed by Monckton; and if it is still unclear I'll try again. The 3.38 is Monckton's notion of what the IPCC has as an upper bound on b (it isn't) and because it is too large, Monckton argues that the IPCC estimate of b at 2.16 is too large (it isn't).
Monckton is not proposing b = 3.38. He is proposing b < 2.16
It's weird on two levels; he doesn't actually carry through with a different value for b; only for κ, and the proper value for b is 1.9 anyway.
Stick with it, by the way! Taking the time to sort through the argument puts you in a great position to point out its flaws. But you're not quite there yet, I think.
I do suggest not always referring to "denialists" and "deniers". I think there are really 3 groups -- AGW supporters, deniers, and AGW skeptics.
ReplyDeleteThe AWG supporters accept the IPPC positon, the deniers deny that there even is GW.
The skeptical group accepts global warming but questions whether CO2 is the direct primary driver, and questions how much influence can be laid to humankind (the "A" part of AGW).
Hi DQ,
ReplyDeleteYes, I see that in the end he uses b=2.16.
My fault--I thought he was merely wrong and had his own data.
But I think TVMOB argues in a rather sneaky way. After all that time using all the MAXIMUM
IPCC values to get a b=3.38, he inserts 2.16 at the bottom into his estimate.
I am surprised that he uses so much IPCC generated data and just tweaks one value to 'prove' his point. He's not an 'eccentric' but
more of a charlatan.
"It is, therefore, prudent and conservative to restore the values κ≈ 0.24 and f ≈ 2.08 that are derivable from IPCC (2001), adjusting the values a little to maintain consistency with Eqn. (27). Accordingly, our revised central estimate of the feedback multiplier f is –
"f = (1 – bκ)–1≈(1 – 2.16 x 0.242)–1≈ 2.095 (29)"
Fooled me once, TVMOB..shame on me.
How very weird; to find myself in the position of defending Monckton...
ReplyDeleteNo offense intended anonymous, but given that it is my blog article that and I am highly critical of Monckton's ability to do physics, I'm going to disassociate myself from the "sneaky" notion in use of 3.38
There's nothing "sneaky" about using 3.38. The argument, such as it is, absolutely requires it. I have spelled out the argument above in a comment dated 22 Jul 16:34.
There are several fatal errors in the argument; but the use of 3.38 should be identified as an error; not as being sneaky. He gets the upper bound of 3.38 by an invalid method; the actual upper bound is 2.6. He only uses it the once, to show it would be a runaway feedback given base response of 0.313, and in context it is plain enough how it fits into the steps of his argument that the IPCC overestimates b. The argument is wrong and incompetent ... not sneaky.
His whole argument is that the IPCC numbers are invalid, and this requires him to use a lot of stuff from the IPCC and then propose a series of corrections. That's not a valid basis for criticism either; it is a perfectly credible way to structure an argument. Where it goes off the rails is not the structure of the argument, but the lack of any physical merit in its details.
Hi DQ,
ReplyDelete"How very weird; to find myself in the position of defending Monckton... I'm going to disassociate myself from the "sneaky" notion in use of 3.38"-DQ
I find using 3.38 to be sneaky because
1. He admits that these are maximas, upper estimates, not averages and you don't add up maximas to determine b. He also 'wonders' why the IPCC decided to take 2/3 of 3.38 sum of maximas.
2. Then he goes on to use the IPCC
b=2.16. In other words, he accepts some IPCC numbers and not others.
Why???
Because he uses b=2.16 to recalculate k in the previous paragraph from NCDC, McKitrick data.
"The value of κ cannot be deduced by observation, because temperature feedbacks are present and cannot be separately measured.(Is that true? Is that how the IPCC calculated k? What about IPCC'lapse rate') ....
CO2 concentrations are the annual means from 100 stations (Keeling & Whorf, 2004, updated). TS values are NCDC annual anomalies, as five-year means centered on 1980 and 2005 respectively. Now, depending on whether the NCDC or implicit McKitrick value is correct, κmay be directly evaluated:
NCDC: κ= ΔT/ (ΔF + bΔT) = 0.412 / (0.560 + 2.16 x 0.412) = 0.284 °K W–1 m2
McKitrick: κ= ΔT/ (ΔF + bΔT) = 0.206 / (0.599 + 2.16 x 0.206) = 0.197 °K W–1 m2
Mean: κ = (0.284 + 0.197) / 2 = 0.241 °K W–1 m2 (26)"
which is Monckton's new value of k.
(And he takes a mean of the two estimates?!)
Seems to be circular reasoning to me. How can k be a function of b?
You said
"His whole argument is that the IPCC numbers are invalid, and this requires him to use a lot of stuff from the IPCC and then propose a series of corrections. That's not a valid basis for criticism either; it is a perfectly credible way to structure an argument. Where it goes off the rails is not the structure of the argument, but the lack of any physical merit in its details."
No. Monckton does'nt say IPCC numbers are invalid, he uses one number b to calculate k using his data.
Monckton says he is just checking sums. The easiest way to make sums work is to arbitrarily fix them so they do and that's exactly what Monckton did.
Good post.
ReplyDeleteI also want to point out that tropical tropospheric warming is not a unique greenhouse signature, but is due to the moist adiabat...so he could just as well have concluded that the "solar signature" is missing. In the vertical, stratospheric cooling is probably the largest "GHG" fingerprint, and that is seen in both observations and models.
DQ,
ReplyDeleteGreat post, along with enlightening comments.
I can just about follow the maths, although I certainly couldn't have got there under my own steam, so nice to see others stepping up to the plate on this one.
Of course, none of it comes as any surprise that a retired politician who studied classics and journalism should produce an error-strewn and muddled 'scientific' paper.
The frustrating thing in all of this is, that no matter what flawless mathematics and science is thrown out to counter Monckton, the denial camp will dismiss it as 'Big Science Lies' or 'Censoring Debate', whilst crowing victory over this latest 'proof'. [sigh]
Oh well, keep fighting the good fight. :)
Cheers.
P.S. SunSword:
I do suggest not always referring to "denialists" and "deniers". I think there are really 3 groups -- AGW supporters, deniers, and AGW skeptics.
I think this is really only true in the same sense that we still have 'evolution sceptics'. The evidence for AGW is almost, if not already, as mountainous as that for evolution. The only serious debate appears to be 'how much' and 'how quickly'.
The denial camp appear to have nothing, other than oil industry propaganda, wingnuts and a handful of discredited scientists. If there's anything else, I've not seen it from much research and arguing with the denial gang....
We might add another word: Obscurantism
ReplyDeletefrom Wikipedia:
Obscurantism (from the Latin obscurans, "darkening") is the practice of deliberately preventing the facts or full details of something from becoming known. There are two common senses of this: (1) opposition to the spread of knowledge—a policy of withholding knowledge from the general public; and (2) a style (as in literature or art) characterized by deliberate vagueness or abstruseness.
Choosing Moncton for creating a denialist piece was an excellent idea by the APS.
ReplyDeleteAs he pulls no weight, taking apart his "analysis" in the publication will nicely illustrate the foolishness of GW Denialism.
Moncton represents the enemy of ignorance and deceit. Not responding in print to the APS is the equivalent of doing nothing while the enemy mugs your neighburs.
Take No Prisoners.
As substantive and well done as this critique is, I still can't help the feeling that this is all akin to a debate about the correct weight of phlogiston. Some models may be more elegant than others and some critiques nonsensical but none of that changes the fact that the accepted concept and predictions of warming remain weak when actually applied to the world. It is not a logical impossibility for both Monckton and the IPCC to be wrong.
ReplyDeleteI have been a lukewarmist for a long time, convinced that CO2 had to have an effect but nowhere near the alarmist scenarios if for no other reason than negative feedbacks are (a) large and harder to model and (b) currently not the most popular focus, and so (c) they would likely tend to be minimized in the final modeling product. But that understandable working bias is hardening into a circle-the-wagons mentality.
I am deeply unimpressed by wind shear modeling as a substitute for all other measures of tropospheric temperature. I am also unimpressed by relocating the "real" fingerprint to the stratosphere as a counter to misbehavior by tropospheric measurements. These smack of wishful thinking in the face of unwelcome fact.
The skeptics’ greatest weapon at the moment is the simple fact that it has not warmed at all for quite a while and AGW modelers and defenders seem to be in denial about that rather than mobilized in a scientific mode to explain why and adjust the models accordingly.
In short, I don’t care what the correct measure of CO2 forcing is if no one can explain why it does not appear to be forcing much of anything at the present time.
Great blog, by the way. Thank you.
-George Tobin
Welcome to the blog, George, and thanks for the accolade.
ReplyDeleteYou raise a number of points; which I can comment upon. I am sure it will not suddenly make you a true believer (like me :-) but it may help to see inside my head a bit.
1. You are perfectly correct that criticisms of Monckton are not justifications of the IPCC. In answering some of your questions I'm trying to take up that other half of the equation.
2. You are wrong about how modeling products work. The feedbacks are properties of the models. You can'r measure feedbacks in real life, because a thermometer cannot tell you which portion of the temperature is due to which of the many contributing causes. Feedback parameters are never obtained directly as measurements, but only by application of physical theory; which is where the models come in. Models ARE the concrete expression of theory. Every time you see mention of the size of a feedback, it is always obtained from a model. There's no other way to do it.
Feedbacks are not something which is modeled directly. Rather, a feedback is just something that happens sometimes in a complex theory. It's a way to describe what the model is doing. For example... we don't model "cloud feedback". We model cloud. Because cloud is both dependent on temperature, and influences temperature, there will be a feedback when you model it.
From our model of clouds, we infer the feedback, as a kind of diagnostic of the model, and by holding various parts of the model fixed (can't do that in real life!) you can measure feedback parameters.
Is this making sense? The "large negative feedbacks" are only known at all because they are already a feature of existing models, and they actually ARE the most popular focus precisely because they are the largest uncertainty in modeling and the largest source of difference between alternative models. The notion of "minimizing them" is pretty close to being an oxymoron. They are descriptions of what is a large part of the model sensitivity already. "Circle the wagons" notion is also an oxymoron. The uncertainty you speak of is a description of how far apart all the various wagons are.
3. On wind shear and signatures, I think you are simply unaware of the relevant theory. The major signature for greenhouse warming has always been stratospheric cooling rather than tropospheric warming, because the tropospheric warming is a common feature of other ways to force warming. Stratospheric cooling is not. There has been no shift involved here.
The troposphere is additional relevant data, of course; but I don't think there is any theory able to explain lack of troposphere warming other then denial of warming altogether. If I am wrong about that, someone tell me. But in any case the major signature of greenhouse is the stratospheric cooling rather than the troposphere.
As far as wind shear is concerned, this is pretty basic physics as well; and interestingly it is one of the major "contrarian" voices in science (Roger Pielke Jr) who was emphasizing the importance of wind shear as a way of investigating temperatures, back in 2001. This is not greenhouse you are expressing skepticism of, but physics.
4. Finally, temperature trends have natural variation. You can quantify this, by taking a regression trend line over a certain length window (five years, or eight years, or whatever) and then slide the window along a time series to see the natural variation in regression slopes. I've done this for myself. For example, take an eight year window. Since 1975, the 8 year sliding window has slopes with a mean of about 0.19 C/decade, and a standard deviation of about 0.17 C/decade (GISS dataset). It is perfectly normal to get a number of eight year periods where a regression line gives slight cooling. But with a 15 year window, the mean slope is nearly unchanged (about 0.18) and the standard deviation for slopes is about 0.06. That is, a cooling regression line over 15 years would be 3 standard deviations away from the mean, and THEN you might start to wonder. Not before.
At present, we are still in the middle of a strong overall warming trend, with a bit of natural variation which we can quantify and check whether or not if conflicts with the trend.
No conflict as matters stand. That's just the maths of it.
Anyhow, feel free to ask about anything, and be welcome.
Thank you for that detailed and thorough response. Let me respond in kind as best I can. Sorry for the length.
ReplyDelete1) My discussion of negative feedbacks was clearly clumsy. Let me try to make the point by analogy:
I worked in cancer research as a lab tech in my youth. The people I worked for generally injected a variety of commercial chemicals in absurd quantities into very small animals in the hope that a publishable event (a tumor) would occur. (It was the era of the “cyclamate” model of cancer.) The search for a list of external causes rather than a search for why the immune system fails in particular instances was the norm because (a) it was easier to gin up a result (b) those who funded and supervised were invested in that paradigm and (c) the technology wasn’t there to do much else, especially the kinds of immunological stuff that can be done today.
That is why I cannot help but see CO2 qua cyclamate—an overfocused paradigm, enormous personal / ideological investments at the top of the funding chain while the more interesting questions are about what might work against such injections don’t seem as central as they should be.
Had I not misused the technical term “feedback” my point may have been clearer. We appear to be trying to define the phenomenon as if what is injected into the system from the outside is the defining entity when the more interesting issue is what it is that (usually) keeps the balance despite such injections.
2) Actually, I was generally aware of the physics of wind shear and I had read Pielke’s comments on the recent research (he seemed a little miffed that his prior work was largely ignored). However, unless there is something demonstrably wrong with both satellite and weather balloon temp measurement technology such that they have both missed a significant warming trend, wind shear remains an interesting line of research rather than an immediate refutation and substitute for inconvenient data from direct measurements made by established methods.
3) I defer to your expertise as to what is or is not the correctly defined fingerprint of AGW but in any event, neither the cooling on top (since 1996) nor the warming in the middle (last 8 years) have behaved as generally predicted. Which brings me to:
4) Lastly, I am intrigued by your figure of 15 years as the minimum time period of significance. The fellows at Real Climate seem to believe the figure is 20 or 30 years. Lucia Lundgren at the Blackboard has been using both 8 to 10 to declare IPCC projections falsified with a lot of rather impressive number crunching (that Pielke has praised). I recognize that there are specific ‘apples and oranges’ issues here but the idea that 15-20 years of non-warming is not a problem for the models while discrete short-term events are routinely held up as proof of AGW (the old “consistent with” maneuver) seems almost disingenuous.
Thanks again for the opportunity to participate in this enjoyable exchange. It was very informative.
Cheers.
-George Tobin
Deniers, skeptics and so on...
ReplyDeleteThe expression you are all looking for has existed in English for some time. It is "people who do not agree with us".
It is normal to have different perspectives on things; but not all perspectives are equal. Some perspectives are better informed than others, and the best basis for figuring out climate matters is physics. Not medicine.
ReplyDeleteI think I understand your position okay, George. Our differences are not primarily from failing to understand each other; but because we really do have different ideas. No amount of "communication" alone will bring us to agreement. We will continue to represent to contrasting perspectives until one or both of us actually has a substantial change of mind. But that is not a precondition for your welcome here, and I'm very happy some of this has been informative.
Your current position, as I understand it, is that you are doubtful that modelers are working as objective scientists, and you are skeptical that carbon dioxide matters as much as folks like me say it does. You express yourself fairly cautiously, but this is where you are leaning, it seems. Clarifications on "feedback" or other points don't really deal with the fundamental fact that you don't actually have any credible basis for your skepticism about the significance of carbon dioxide. If you try and rephrase to avoid what was wrong with your first line of argument, you'll simply get another incorrect line of argument. No offense intended!
You now explain your perspective using medical analogies. They describe how you see the matter, but not why. (At least, I hope not! If you actually have conclusions on climate BECAUSE of medical analogies, then you have pretty much no chance of ever developing any meaningful view of the field.)
The basic physics of carbon dioxide is not in any meaningful doubt. It has a large impact, quantified as a forcing, by basic thermodynamics and radiative transfers. It is a significant part of what makes our planet a livable climate at all. Without a greenhouse effect, the surface temperature would average around -18 degrees C. The 33 or so degrees warming we get from our atmosphere follows, by physics, mainly from the effects of water and of carbon dioxide. (There is a nice readable overview at Water vapour: feedback or forcing?, at realclimate.) You can't simply allocate a fraction of the effect to each part; they work together. Water gives most of the actual interaction with radiation, with carbon dioxide giving a significant secondary interaction. On the other hand, water falls in and out of the atmosphere almost immediately by evaporation or by precipitation; the amount of water in the atmosphere depends strongly on temperatures.
The above paragraph is the substance (in overview only) of the argument. Now, I'll use an analogy. Remember; the analogy is not the argument, only a way to help make the substantive argument more comprehensible. Carbon dioxide and water work together a bit like a guitar and amplifier respectively. Most of the sound comes from the amp, plus a smaller amount from the guitar. Most of the warming comes from water. But the sound level is still determined by the guitar, because that is what actually forces the system.
To think that people are inflating the importance of carbon dioxide is, frankly, merely ignorance of the basic physics of the whole equation. The importance of carbon dioxide and the significance of having a large increase in atmospheric greenhouse gas levels is not in any rational doubt. It's in plenty of irrational doubt, and that is basically a problem of education. This is not a "debate" in the normal sense between credible alternatives. It's a particular field of science with some well established fundamentals and a lot of important open questions, which is being systematically distorted and misrepresented in public discussions by spurious arguments on the well established fundamentals.
Many onlookers are sincerely confused and don't know who to trust. I sympathize with them, but they are not struggling with equal alternatives. They are rather unable to tell the difference between good argument and bad; which is not unusual when faced with a topic in which you have little technical background.
I don't expect to persuade you to just fall over and accept my position! You are going to have to continue trying to sort out who to trust and what to believe, and why; as we all do on many topics. You remain welcome here in any case, with no requirement that you'll actually agree with me.
On your other points, quickly.
2. You are wrong about temperature measurements and wind shear. There is no "direct measurement" here that stands as a simple hard value to be explained away. There is the stock standard scientific issue of a hard to measure quantity being constrained by as much data as we can find, and with ongoing work sorting out calibrations and biases.
3. The stratosphere IS behaving as expected. Measurements fit expectations quite nicely thankyouverymuch. Whether or not the troposphere is behaving as expected depends on what measurements you are working with. There are some discrepancies; but given the uncertainties they are not as much as you seem to think; and ongoing progress to nail down the temperature record is tending to confirm the expectations from physics and measured surface warming. The biggest discrepancy with the troposphere is a set of old measurements which were distorted by a basic algebraic error by the scientists who raised the issue. Since that was fixed, the discrepancy has been comparatively minor, mostly within error bars, with a small number of scientists making a kind of rearguard case for the discrepancy which is becoming harder and harder to sustain in the light of new data.
4. My 15 year window is based on a very crude analysis method and a simple 3-sigma deviance from a simple mean; it is entirely my own analysis, done with a spreadsheet at home and some downloaded data. A 15 year window showing a regression line with falling temperatures would, I suspect, be cause to start to wonder about an additional systematic forcing effect beyond what is at work over the last thirty years. I can think of several ways that might happen (systematic effects from multi-decadal oscillations, for example) so I'd not immediately shout "disproof". The real point is to explain why an eight year slow down is insignificant. That kind of variation is part of conventional expectations.
However! If there is a real substantive difference between me and the experts, an onlooker is much safer to put their money on the experts. I am just an amateur enthusiast. I do try to form a critical opinion of my own on the whole field, by reading the professional literature and doing my own analysis on available data. That is primarily for my own benefit. You really don't have to trust the experts blindly in everything; learning about the field is another option. It's a hard option; it can't be done overnight. But it is an option.
Thanks for a blog, just discovered, which is about the only AGW advocate blog I have found with a reasonable, polite tone - and which doesn't descend into instant wholesale abuse of those who 'think different'.
ReplyDeleteContinuing the dialog about CO2 and water vapor, is it the case that what sparks the increase in water vapor is a rise in temperature? Is this right? What happens is, we have a small rise in CO2, that then produces a small rise in temp, and this rise in temp then produces more water vapor. This rise in water vapor then produces more warming, and do on, until we reach some limit to absolute level of warmth determined by other factors.
This is the positive feedback we are talking about?
fred
That's right Fred, you've got it.
ReplyDeleteThe one minor point is; you don't actually need "other factors" to stop the feedback. If you apply the "incremental" method directly, you get smaller and smaller increments which quickly vanish away to nothing; and the whole effect is a simple amplification by some factor of the initial stimulus.
You can also calculate the whole thing much more directly as follows.
The first thing to note is that temperature is driven by energy flows. We have energy flowing in from the Sun, and also being radiated back out to space. These two flows are in balance (I'm telling a little fib there, to allow us to keep it simple; mathematically we are describing the "equilibrium condition" in which the flows as in balance; generally it takes a bit of time to reach this equilibrium, but let's ignore that for now.)
The hotter the Earth is, the more energy it radiates. If there is an imbalance of energy coming in, that will heat things up until the radiated energy output is once more in balance with the input.
For every degree of surface temperature, you get another 3.2 W/m^2 of radiated energy.
However! As the earth warms up, the water vapour effect you describe (plus other effects, listed in Monckton's article and my blog post) changes, with the result that extra water vapour keeps a bit of heat within the planet.
For every degree of temperature, you get enough water vapour etc added to the climate system to result in another 1.9 W/m^2 of energy retained back in the Earth.
Now. Suppose we "force" the whole planet somehow; by adding energy at the rate of X W/m^2. As a result, the planet is going to heat up, by a certain temperature T.
We can calculate how much it heats up with this equation:
F + 1.9 x T = 3.2 x T
This says that the forcing we added (with CO2, or with reduced albedo, or with very very heated debate, or anything else) PLUS the extra 1.9 x T from the water vapour etc, must match up with the additional radiated energy of 3.2 x T
Solve... F = 1.3 x T
Or equivalently, the temperature goes up by F/1.3
Note that without the feedback effect, it would have gone up by F/3.2
That is 3.2/1.3 ~ 2.5 times as much effect. It is like an amplifier, multiplying the effect by 2.5.
The number 1/1.3, or about 0.77, is also called the climate sensitivity. It says how much things heat up for a given forcing. This sensitivity is one of the big open questions in climatology. We know it is roughly 0.75 or so. But it could be more; and it could be less. The range is something like 0.5 to 1.2, and there's a lot of work and interest in trying to determine it more accurately.
Duae,
ReplyDeleteThanks for this blog of knowledgeable people.
Although not a climatoligist I am good at math and physics and understand most of what is being said I think.
It is my understanding that without "feedbacks" the underlying energy added by CO2 is about 1/3 or less of the total temperature change predicted for doubling CO2. Therefore it seems to me the entire debate really centers on the feedbacks because they are the responsible for the majority of the temperature change.
I don't think most people understand that. It is important because the physics of the heat caused by CO2 is rarely in dispute even by skeptics I believe. I think what we all are concerned about is that we then suddenly take a fairly unquestioned number and triple the amount of temperuture change (or more) because of a "guess" with far less proven and understood physics. You admit several times that it is "impossible" to actually measure feedbacks so they are based on models.
You have to admit the models are something of a piece of "work." There are so many assumptions and unknown relationships, missing relationships potentially. The entire methodology is grossly unscientific in the sense that the stepwise approach to temperature or climate prediction is proven to be nearly impossible. Anybody reading anything about chaos theory will be horribly skeptical of these predictions. Anybody with any computer, math or science background will understand that any "model" that attempts to step and step and step iteratively producing more inaccurate results one upon another is unlikely to result in any meaningful output. There are so many examples of this it is hardly worth mentioning.
Therefore my principal problem is not whether the forcing is 0.3 or 0.6 or 1 degree or whatever. The real question is how do the "scientists" possibly justify confidence in a computer model which you admit is essential for determining 2/3rds of the entire temperature change? A computer model which anyone of almost any scientific background would be intensely skeptical of.
Mr Monckton explains why he believes the feedback is less than the IPCC. I have no confidence in any of the theories (his or others) of these feedbacks because they are not based on the same level of physics as the CO2 itself is. Monckton could be right or Hansen or others. I don't believe anyone can say at this time.
I think the scientific community should make this clear because on the one hand you have papers being written and people saying "AGW" is undeniable and then others saying that it is a hoax. I think both are right but what is really in dispute is not whether CO2 causes warming just what the amount and time period will be. If the warming is less than 2 degrees or happens over a time period of >100 years then the argument is largely irrelevant from a public policy political perspective. it is the insistence of certain scientific members that they are right and the warming WILL BE >2 degrees and in less than 100 years that is so disturbing given the shaky scientific underpinnings of such statements.
I particularly am intrigued by your use of the 15 year window to "prove" or "disprove." The problem is that we are in a 11 or 12 year period here where a trend is either flat or down. Given the lack of heat in the ocean and the unmeasurable heat effect in the troposphere and the lack of land temperature increases it is hard to see how we will get any substantial increase in the next 3 or 4 years. It seems the skeptics are almost locked into winning based on the 15 year basis. The Nature article published just a few months ago said as much. On top of that are the PDO and NAO phenomenon which appear to be reversing and we are seeing these effects just starting. Several distinguished climatoligists believe these are overriding effects and could last for 25 or 30 more years. There is the issue of the sun although I remain unconvinced there is a correlation over time that is interesting. I have no idea how the sun might affect our world (spoken a little facetiously) but I understand that the apparent variations in solar radiation seem too small to have an impact. I have wondered if the strong magnetic effects of the storms that produce spots could cause interaction with our earths magnetic field or somehow affect ionic behavior in clouds. Has anybody thought of that? Could a rapidly varying magnetic field as opposed to a slower one cause effects on climate? Possibly the atmosphere is sensitive to particular frequencies we don't understand. All I know is that there is a compelling case to be made (frankly better than the CO2 relationship to temperature posited in the past). The historical relationship of CO2 to temperature appears irrelevant to me since it is obvious that the CO2 followed the temperature rises and this was largely due to ocean outgassing most likely. The physics is totally different from what is now postulated to be occuring where the CO2 is driving temperature not the other way around.
Anyway, what bugs me more about the 15 year time window is the fact that the modelers can't have it both ways. Either their models are accurate (which they argue) in which case a 8 year divergence is unexplainable and shows some missing phenomenon from their models OR their models are inaccurate (likely) in which case their predictions for 2100 are bogus. They can't have it both ways. They can't say look how well we've fitted the data in the past to our model and claim accuracy and then turn around and immediately right after producing their model for the next 10 years fail miserably to predict a flatline.
In science it is usually predictions that make or break a theory. In 2001 the IPCC predicted a temperature trend and although their are caveats of course they failed immediately! That is very disturbing to me and typical of many computer model simulations. Very small errors in assumptions and the physics models can result in gross errors and mistakes very quickly. The fact they were able to model past data is not particularly impressive from a scientific theory point of view. I hate to put this so bluntly but it is trivial to construct many models of past behavior which all fail immediately to predict the immediate future which is exactly what happened here. Maybe the models will "pull it out" but it is not the purpose or method of science to be arguing for the least likely scenario based on a blind belief in a theory. Scientists are usually skeptical and leap on data which contradicts a theory with glee. What i see in the AGW crowd is instead signs of panic reaction, attempts to squash debate, an almost religious belief that the underlying result is correct (even if there are many holes and assumptions made). That strikes me as dangerous and scary trend in science.
Lastly I think you have done a good job showing errors in Mr Moncktons article. Thanks for that. I think though on the whole he does agree that CO2 increases temperature. His main arguments are that without tropospheric warming the apparent forcing can be inferred to be a lot less than would be obvious based on the physics but even more I think his arguments rest on the fact that the feedbacks are not proved and are subject to vast error and interpretation.
As you point out to settle the argument of feedbacks we have to look at the data. Unfortunately the data is extremely uncooperative at this time. Even assuming the troposphere data can be fixed it is hard to understand ocean temperatures falling and the lack of land temperature increases for so long. There must be something else going on here and that is the most compelling argument to me. We just don't understand well enough to make these pronouncements like we are 95 or 99% certain as Hansen does.
Lastly on the wind data to "fix" the troposphere it seems to me as a layman that there are many assumptions made in those calculations. The idea we understand all of the factors and phyiscs that affect wind with more accuracy than temperature measurements is not obvious. Maybe it is obvious to you but I read those papers and frankly they look as full of assumptions as many of the models assumptions about climate behavior. Therefore it seems highly unlikely that these are more accurate than the satellite radiosonode data seems quite non-intuitive.
Thanks for your time if you read this.
Welcome, saturn. Thanks for taking the time to give a long comment.
ReplyDeleteA comment stream like this is not a good place to carry out a debate on climatology; and unfortunately, there is a tendency for discussion keep expanding until we've covered the whole field. Comment streams are also really awkward for writing, and I don't much like the blogger comment facilities. I'm going to attempt a response to your various claims and comments; but I may not go into a long to-and-fro exchange afterwards.
I will also be very dismissive of saturn's claims. Some folks have said nice things about the tone here, and I'll try to maintain that. But don't mistake that for my having more than usual respect for the arguments themselves. I aim to look carefully at all arguments on their own merits; but not because I'm undecided. It's just my preferred personal style, and it is the foundation of my confidence that AGW-skepticism arguments are profoundly irrational and riddled with misunderstandings of the science.
The heart of the problem of what word to use for the AGW-skeptics is that their arguments are so dreadfully bad. Any word used by people who actually understand the science of climate will tend to carry disparaging connotations. And so it should. This is not merely a matter of being rude or disrespectful. It is a well informed opinion on the standing and merit of arguments being used by the AGW-skeptics.
So saturn! – welcome to my corner of the web. I'm glad to have you here, and I have no expectation or demand that you will change your mind and accept my position. I include here a point by point response, which can stand side by side with your comment, and readers can see both views, to check out further for themselves which one is more sensible. There's no aggression here to you personally, and you are welcome.
(1) Saturn says: "the entire debate really centers on the feedback". That's not a bad summary, if you want a one-line summary of the big issues in a large field. The feedbacks can be quantified as something from 1.4 to 2.4, centering on 1.9. This is what Monckton calls "b". The real science and the genuine open questions are involved in trying to constrain that number. There is a large body of good solid scientific work applying theory and empirical observation from many different lines of investigation to give the currently known constraints, and ongoing work continues to chip away at the problem. In the meantime, irrational skepticism is thinking it is closer to zero; or that because it is unknown it means we can dismiss all constraints of any kind already discovered by science, or that because it is complicated the scientists who are studying it must be guessing, or incompetent. Nonsense.
(2) Saturn says: "You have to admit the models are something of a piece of work." In fact, I have to admit no such thing. The models have contributed enormously to understanding; and they continue to be refined and improved in various ways. But you don't need complex climate models to get the basic facts routinely denied by AGW-skeptics; such as the fact the planet is warming up, and the fact that the major cause of warming in recent decades is greenhouse gases in the atmosphere. The models are rather the concrete expression of all the relevant physics of thermodynamics and chemistry and fluid flow to try and constrain the details. Along the way they have confirmed the straightforward fact of AGW, but that is secondary. There's a long way to go in the whole modeling area. Cavalier dismissal of all the progress that has been made is irrational; and the implication that it is all based on unreliable climate models is false. The main facts of AGW follow from measurement (for warming) and the physics of radiative transfers (for the critical role of greenhouse gases).
(3) Saturn says: "The entire methodology is grossly unscientific in the sense that the stepwise approach to temperature or climate prediction is proven to be nearly impossible." This is flatly false; the remark has no foundation in chaos theory or anything else. The methodology is routine science, used also in all kinds of other fields without qualm. One of my favourites (I love astronomy) is the detailed physical modeling of a supernova explosion. The methodology is the same; the difficulties are similar, both deal with chaos and use stepwise gridded simulations, and the science is cutting edge.
Don't get me wrong here – projections of climate models are inexact and there are all kinds of aspects of climate that they have lots of trouble with. There is a lot of work involved in validating their results, and quantifying their inaccuracies, and extending their scope. Projections can't simply be the readout of a model. Model-based analysis results in a range of possibilities and likelihoods. But fundamentally – the range of legitimate uncertainty cannot possibility encompass the extreme skepticism of those who deny AGW.
(4) Saturn says "I particularly am intrigued by your use of the 15 year window to "prove" or "disprove." I think you are reading too much into this. I ran a very simple naïve analysis – which is all you need to show the basic error underlying AGW-skeptic claims that warming has stopped. An eyeball of the temperature graph shows that there's a strong warming trend since 1975, and that the trend is not uniform. A bit of maths shows that the recent slowdown is well within the natural variation that is easily visible in a plot of measurements.
(5) Saturn says: "Given the lack of heat in the ocean and the unmeasurable heat effect in the troposphere and the lack of land temperature increases…" All the various claims about measurements and distinguished scientists and what not simply do not match up with what is going on in the literature. Claims of oceans cooling, and troposphere cooling, are particularly egregious errors. Both are founded on cherry picking old papers with surprising results, and including errors discovered since publication and recognized even by the scientists who made the original claims. There's still ongoing debate and cleanup of the details; but the main "cooling" results from a few years ago were just wrong; though they do get recycled indefinitely in the popular debate. The land temperature thing is fluff; land temperatures are still increasing, more strongly than the sea temperatures, as expected.
(6) Saturn says: " The physics is totally different from what is now postulated to be occurring where the CO2 is driving temperature not the other way around." No, the physics is exactly the same. What's different are the circumstances to which the physics is applied. The physics, in both cases, tells you that CO2 has a significant warming effect; and that CO2 exchanges between atmosphere and ocean. The current circumstance is a huge increase in CO2 from geological reserves (fossil fuels), all over a very short period of time. The physics says that the ocean will take up a lot of this CO2, but gradually. (Confirmed; something like 40% of human emissions have ended up in the ocean already, making it more acidic.) The physics says the atmosphere and surface will warm up. (Confirmed; measured.) In the ice ages, the physics says that rising temperatures reduce the solubility of CO2, resulting in a transfer from ocean to atmosphere. The heating effect of that extra CO2 then gives a positive feedback to heat up even further; and this additional heating is essential to explaining the temperature cycles in and out of ice ages. Basically, in the ice ages CO2 acts as a positive feedback over a scale of hundreds of years. In the present, CO2 acts as a forcing thanks to human transfer from geological reserves to the atmosphere. Physics is precisely the same in both cases, and the study of ice ages stands as an independent confirmation of that physics, and also as a useful way to estimate the climate sensitivity… the same as point number (1) above.
(7) Saturn says: "Either their models are accurate (which they argue) in which case a 8 year divergence is unexplainable and shows some missing phenomenon from their models OR their models are inaccurate (likely) in which case their predictions for 2100 are bogus." This omits the obvious. The models are accurate for capturing trends, and also the kinds of variation you should expect around a trend. The 8 year divergence is precisely the same kind of variation seen in the models.
Models don't just give a sequence of temperatures. They give many sequences; obtained by repeated runs with small changes in starting conditions. Have a look at What the IPCC models really say (realclimate), or the diagram in FAQ 8-1, page 600 of the IPCC 4AR on the scientific basis. Analysis of model results allows you to infer a trend, and a level of natural variation about the trend. The models are not perfect; but in fact they do pretty well in capturing current and historical records, and the 8 year divergence is precisely the same kind of natural divergence that also shows up in the models.
----
So, in conclusion: the AGW-skeptics often complain that they are treated with disrespect. I want to avoid that; but on the other hand the actual arguments here are pretty much worthless. Any consideration of such material on its own merits will come across very dismissive and disrespectful indeed, and rightly so. Arguments don't have a right to respect in the same way as people; and the arguments repeated by saturn are dreadful. They carry no impact at all in the scientific world, where their flaws stand out immediately, and they serve only to muddy the water in popular debate.
I don't doubt saturn's sincerity, and I don't actually expect him to be convinced by my response. It can be really hard to sort out these matters; and I understand and sympathize on that difficulty. Here is my response in any case.
My question then is a very simple one. We know that in historical times there have been temperature rises of the same order as those that occurred between 1975 and 2005. So why did they not lead to this feedback and further warming effect? And what brought them to an end and caused the subsequent cooling periods? Like, the Roman warm period, and the MWP is what I'm thinking of.
ReplyDeleteLogically it would seem you have to argue either that there was no such warming and cooling, or that the feedbacks did happen but we did not know... or that the warming was somehow different in its effect on the feedbacks... or? But in any case, the question remains, what brought about the previous coolings?
Fred
They did have feedbacks in the same way then, as now.
ReplyDeleteFeedback is nothing more than a way of representing all the ways in which temperature responds to energy imbalances. Water evaporated in the past just like it does now; that's feedback. The Earth warms, and cools, in response to changes in energy balance in the past in precisely the same way as it does now.
I'm trying to guess why you think this is a difficult question. I'm not sure, but perhaps you think feedback means that there has to be some sort of infinite loop and unending increase. That's a special and unusual kind of feedback which doesn't apply here. There's no runaway involved.
Thanks so much for your response.
ReplyDeleteI think you have confirmed that there really is little difference of opinion about the basic physics of CO2 heat capture. It really bugs me to see either side engaging in politics because I feel it really cheapens science. One of the things that attracted me to your blog was it appeared to be knowledgeable people willing to consider everything. So, I found your mean-spritited comments about "skeptics" to be disheartening. I would expect scientists to engage in debate and to discuss the facts as you did with Moncktons paper rather than the debate shutting approach of many.
Frequently when I am trying to squash a bug in a computer program talking to someone who knows little about the subject is helpful because they make me think about things in ways I never did before. So, I find the dismissive nature of both sides in the debate to be unhelpful and dangerous to science. If the public perceives that science becomes too political and not about truth above all else then all science will suffer a huge death and damage. We need to be able to be honest about what we know and don't know because the future of science hangs in the balance. I am very worried that scientists have put us all into a black hole where the collapse of the AGW hysteria will come back to haunt every scientist and produce recriminations and disbelief of scientists in the future. It is now clear to me we are very possibly not going to see a 2 degree increase by 2100 and when the general public becomes aware of this they will be mad and we will all rue the day Lord Hansen got up and said he was 99% certain bla bla bla....
It seems we agree the feedbacks are the most important point of contention. Unfortunately in this field it is impossible to go back and know with certainty much past data. I am not saying there is not some rock solid numbers but much of the temperature record is in dispute for instance. We have only a few proxies for much of the data. For instance sea temperatures were measured by leather buckets, insulated buckets, engine inlet temperatures and any combination of the above for most of the last century. While we might have data on temperatures in any one region knowing if those temperatures were common across the globe is unknown or unknowable. We have clearly had periods of warm and cold that are scary in their severity compared to current times. What is obvious then is that there must be factors that drove all those variations and until we understand these factors it is impossible to make predictions with confidence about the future because we simply don't know what other effects that have affected temperatures in the past will recur. All such predictions would have to be caveated with: "well, unless we get a volcano of a certain size or unless we find that the sun has a massive corona or we don't get hit with a comet or whatever we can't predict or know." That is not to say that there is no value in predictions but one thing I found disturbing from the first time I read the IPCC 3 reports was that they specifically excluded volcanoes from their models of the future even knowing that volcano eruptions are common and happen 1 or 2 times a decade. A quick examination of the record shows these occur frequently and with huge impact on climate to the downside. Why didn't the IPCC factor in a fudge downward to take into account an assumed volcanic activity for the century? They fudge everything else in the models? This is not a putdown but simply fact that there are many fudge factors and assumptions of initial conditions or other parameters.
This is simply the barest foot in the door of the problems with the IPCC methodology. Reading the reports is very discouraging because so much is obviously assumption. Nonetheless as you point out it is a working hypothesis and working models are getting better and better. Nobody wants to stop the process from improving. Knowing the future climate is clearly a very good thing to know. I personally am more interested in knowing this to predict and prevent any declines in temperature in the future not to prevent increases. It is very clear to me the damage from decreasing temperatures is order of magnitudes larger than increasing temperatures.
How do we get to a common basis for models and computer simulations? I remain profoundly skeptical. I am skeptical for a huge number of reasons. 1) the programs could be simply programmed wrongly. What is the quality control process the groups use? Who does the code review and what are the ways they use to check they work? 2) how do we know the models are stable? Almost all computer models will eventually show asymptotic behavior with some inputs. It is the nature of the mathematics input into the stepwise process that can't understand every physical thing that happens to limit things. For instance, the models have to be started with initial conditions that aren't based in real numbers determined from experiment. The models produce bizarre results like the entire atlantic ocean freezing into a solid chunk of ice all the way to the bottom. This is an artifact of the fact that the models don't understand all the physics. 3) the models make assumptions about how everything interacts that are unproven. Each of these interactions needs to undergo its own intense study and vetting and quality control and yet there may be interactions we simply don't know or understand. 4) the whole idea of iterative model production is flawed since every iteration will produce results that are in error, the errors build upon one another till the end result is meaningless. This is why the error bars on the models results are truly closer to +13 degrees to -10 degrees for 2100 instead of the +2 to +4 degrees commonly bandied about. Even the modelers admit that the models cannot be used for prediction. They are sensitivity analysis tools to help identify what happens if you change one parameter what affect will this have. The modelers themselves would not be so bold to suggest that they know what the temperature in any region of the world will be in 10 or 20 or 30 years let alone 100.
This is just the barest start of the problems with the models. The point is not to debate each of these points but to point out that the physics and surety of the models is WAY more suspect than the underlying physics of IR capture by CO2. Since the models are responsible for predicting the vast majority of the suspected heat increase for 2100 it means that it is impossible to say that we are 95 or 99 % confident in our results or that the physics is proven or the kind of political poppycock that Lord Hansen goes to congress and says. It's simply impossible to be a scientist and claim such knowledge given the state of the models.
What I am saying about the current predictive failure of the models is not controversial. Many IPCC members including the lead author of the feedback chapter has already concluded that the results need to be modified substantially. Some think it won't be that big an adjustment but it is clear that the response of the enivironment to large increase in CO2 (a 10% increase in one decade) has produced NO increase in temperature in any way anywhere, neither in the troposphere, the land temperatures or the ocean. In fact buoy measurements of ocean temperatures from 2003 to 2008 are DOWN. This is not archaic information as you implied. The most recent buoy measurements from the ARGO buoys are down for 5 years. This is why the German science team got a peer-reviewed article published in nature predicting no temperature increases for 10 more years. This means that your 15 year time window is gone. We will almost certainly get a 15 year flat or down period which seriously degrades the models accuracy.
As scientists we must always be skeptical of our theories. The mere idea that "skeptic" is a bad word in science or that science is some kind of "religious edifice" that we all must defend current theories to our dying breath or something is absurd. Science is about truth and the next piece of data and any theory can become trash overnight to that truth of that measurement. The lack of a Higgs boson will be crushing for physics and most of the current theories. We may discover in the next year if physics itself is under massive change again. We don't see physicists running around saying those who don't believe in the Higgs Boson are unscientific or "evil-skeptics" or something. So, it is absurd to read that people have so much confidence in a theory of climate with so little solid information, so little proof, so little predictive ability. Please don't insult science by trying to imply we know more than we do. We have theories of climate change and climate prediction. Some of them seem better founded and provable and predictive than other parts but we are certainly not in the position to proclaim we understand the problem to a 95 or 99% certainty. Such proclamations scare the dickens out of me because of the very high probability we are wrong given our track record.
The very minimum to establish a greater degree of trust in the models and the feedbacks and AGW in general is to be able to explain the current 8 year, 10 year lull more clearly. I was very comforted by the idea we understood how particulates either from man-made pollution or volcanoes modified temperatures in the 20th century. That is very impressive. Until scientists can explain with more understanding why the last 10 years have been flat or down it is simply irrelevant that the data fits within the error bars. That's not good enough for us to believe in the theory and models with confidence. We must understand why the very first predictions of the models are immediately wrong and so badly off. Yes, they may come back into alignment. Yes, the error bars are big enough to accomodate a few years divergence but it creates enormous doubt about our ability to predict and the more protestations I hear and attacks at skeptics doesn't help. It only makes the science look cheap and unsure.
>6) Saturn says: " The physics is totally different from what is now postulated to be occurring where the CO2 is driving temperature not the other way around." No, the physics is exactly the same. What's different are the circumstances to which the physics is applied.
ReplyDeleteI think you misunderstood me. I agree with most of what you wrote in your reply to me including this part. All I was saying is that CO2 went up previously after temperatures went up and i agree we know why that happened. I have seen people point out that CO2 levels were consistent with the temperature at the time but the temperature appeared to get that high without the CO2 input. That makes one wonder why didn't the temperaure double soon after the CO2 increase happened? If the temperature was up 10 degrees 100 million years ago and we see that 500 years after the temperature jumped 10 degrees that CO2 climbs to 20 times current levels then I would expect ANOTHER 10 degree surge because of the additional CO2. Obviously the feedbacks in this case were negative to the CO2 input. Not only that but temperatures managed to fall precipitously even though CO2 did not decline. If anything the historical data seems to imply that some kind of feedback is essentially negating the effect of CO2 even when CO2 levels are 20 times higher than todays. This simple analysis should have led scientists to be skeptical of the positive feedback coefficient values in the current models or to at least propose models with much less positive feedback.
> (7) Saturn says: "Either their models are accurate (which they argue) in which case a 8 year divergence is unexplainable and shows some missing phenomenon from their models OR their models are inaccurate (likely) in which case their predictions for 2100 are bogus." This omits the obvious. The models are accurate for capturing trends, and also the kinds of variation you should expect around a trend. The 8 year divergence is precisely the same kind of variation seen in the models.
Do the models understand the PDO and NAO phenomenon? I have not seen that. I believe they think they have the physics in the models to simulate the PDO or NAO phenomenon but it is not clear to me they actually can model these phenomenon. That is important because of course these are on a current trend to decrease world temperatures and the arctic in particular over the next 25 years. The climate models are predicting behavior counter to what we have observed for over 100 years in the NAO and PDO phenomenon. Frankly, as many people have pointed out a large part of the trends since 1975 can be explained by any number of models including the PDO and NAO phenomenon which aren't scientific theories but still explain the data as well as the models especially if one considers the last 10 years. It is trivial to construct thousands of models which fit past data. This is a mathematical fact. Especially given the lack of solid data and error bars that are apparently assumed to be sufficient. I saw one paper which showed that a simple flat line linear model of the last 25 years was more accurate than all 22 models considered in the IPCC report AR4 or even the average of all 22 models. So, constant emphasis of how good the models are at simulating past data is not convincing. I continue to be amazed at how supposed smart people continue to make this error. It is not hard or surprising that people can create models to fit any arbitrary set of data to any level of accuracy desired. That is a trivial mathematical exercise. The fact that the models are complex doesn't make them any more convincing.
As I said the fact that the models predict past behavior "very accurately" is not good because it then makes it very difficult to explain their current misalignment.
There is a conundrum here which I am not exploiting. I understand that in order to get better models we need to keep iterating and there will be errors and improvements. I am simply saying that it is not understood by the general public that the vast majority of the "climate change" predicted by the IPCC and AGW enthusiasts is not based on solid physics that is proven but is instead based on largely very unproven and quite problematic models that have failed to predict very well the future.
From a scientific point of view it is only relevant what they predict for the future and they are divergent at this time and unlikely to converge anytime soon given sea temperatures as the German science team pointed out. We are almost certainly in for a 15 year haitus or more in temperature increases, maybe 20 years if the germans are right. This means almost certainly the models are wrong. I don't see the point of belaboring this point to death and defending to death something which is bizarre to defend. These models are incredibly complex and undoubtedly filled with huge numbers of errors and misconceptions and missing factors. To defend them is pointless. What we need to understand is why they are wrong in the last 10 years specifically and correct and see if we can do better.
All of this makes the projection of 2 degrees by 2100 incredibly problematic because it will require a very steep slope of temperature increases after 2013 or so to get to 2 degrees or more by 2100. Such a slope is unprecedented even in the 80s and 90s. Even if we repeated the temperature spikes of 1910-1930 and 1980-2000 over the rest of the 21st century without any more "unexplained pauses" and the NAO and PDO phenomenon disappear we wouldn't get 2 degrees. In order for us to get to the predicted (low end) of model behavior by 2100 we need to see an unlikely and unseen before temperature increase pattern. Maybe you believe that and maybe it will happen but it is not the purpose of science to make leaps of faith.
It is clear that once the models are modified to represent new data and are reset to new current initial conditions that they will not show the 2 degrees by 2100 previously calculated. Let's hope the new models work better and at least get a better start than the last batch. Let's hope we can explain to the public in a rational way why we were wrong about 2 degrees. It just doesn't seem likely anymore let's face it sooner rather than later or the damage will be much worse if we let people like Hansen go out there and tell people we are 95% certain when we aren't. He is attacking science really by making such claims.
This is about the point where I start to give offense; which doesn't bother me. It seems to be an inevitable response to the basic conclusions, no matter how carefully expressed. So be it. I will not be giving a comprehensive response to all the above by saturn, but will make a couple of basic points. As always; no offense is intended, but some of this will be sharply critical, as is appropriate. You need to wake up to yourself, saturn, and no-one likes to be told that. I sympathize, but sugaring the pill is not doing you any favours.
ReplyDelete(1) This IS a political debate, as well as a scientific one.
Complaints that engaging in politics cheapens the debate are naïve, and usually hypocritical. The conclusions of science on this issue have important political implications, and it is right and proper for scientists, like any other responsible citizens, to get involved in politics and decision making.
Responsible decision making is guided by the analysis of risks and costs, and that is informed in turn by science. In turn, governments can and should give support to research guided at least in part by what research questions are of political and social importance.
Where this goes off the rails is when support is given to research guided by the answers desired for political reasons. Political considerations should have no part whatever in the conclusions obtained. The whole point of having scientific investigation is to get useful answers to basic questions which are NOT distorted by political desires for one answer over another.
In the present circumstance, the distortion is almost entirely in one direction only. There is a flood of the most appalling scientific gibberish being dressed up as a cheap parody of real science, intended to support outright pseudoscientific nonsense on climatology. It's not happening in reverse on anything like the same scale. The scientific community in general shows the same high standards seen throughout the practice of science, and those actually working on the subject come down in a solid block to recognize the basic reality of anthropogenic global warming.
(2) This is not a debate between equivalent alternatives.
Many people are sincerely confused about who to trust; and there is a lot of pseudoscientific nonsense being actively spread about by non-scientists and pundits with grotesquely inflated claims of expertise, and – tragically – a tiny handful of scientists who have prostituted their scientific integrity for whatever reason. At the same time, there is also a vibrant scientific debate on many questions which remain wide upon and a focus of ongoing research, and also a few fairly extreme scientific mavericks; who as always remain an important part of the whole scientific enterprise.
People with no background in the topic may find it hard to distinguish the pseudoscience from the legitimate division of opinion on genuinely open questions. They may find it hard to distinguish legitimate but isolated maverick ideas from well grounded basic conclusions. I sympathize… but we are not all in that same position of confusion, and I make no apology for declaring that up front.
It is easy for anyone with a little bit of background in the relevant science to see the flaws in a paper like Monckton's. The more background you have, the more the flaws are obvious. Merely pointing out the errors dispassionately, without any whiff of personal criticism, is a terrible idea. An important part of the message for the general public is that Monckton's paper – and many others of that ilk – is not any part at all in the legitimate scientific debate.
I personally think it is important to pull out the flaws and show precisely where they are wrong, as a part of showing that Monckton's paper is not rejected simply because of his history or because we don't like his conclusions. The paper itself, on its own immediate merits, is dreadfully incompetent. Showing this is important for the sake of sincere non-experts who want to know why Monckton is treated so derisively by the experts.
Many others will simply say "Not Monckton again" and not even bother to look at the argument. They are RIGHT to do so.
(3) Yes, we really are sure about anthropogenic global warming
Much of saturn's article just reiterates the same confusions I addressed previously. He's flatly wrong about there being a big problem about recently cooling, or about predictions being substantially off. I have already explained that models include the expectation of natural variations; and that the recent slow down is well within normal variations as both seen in the past and as predicted by models.
The oscillations of NAO and PDO are oscillations. They are part of natural variations and cycles. They are one of the areas of active open research and investigation, and they are not at this point predictable with any level of confidence. It is pseudoscientific nonsense to take that as a sweeping refutation of model based research; because we already know that models have limited accuracy, and we already make conclusions with substantial confidence bounds that take into account what is not well known. Model simulations already show lots of variation analogous to major oscillations in the real world. Saturn may be sincerely unaware of that, but there you go. That's precisely the problem. It's not easy for a novice to distinguish the genuine open questions from the pseudoscientific distortions of those questions.
(4) Claims that new data is disproving the models are flatly wrong.
Take a look at saturn's last paragraph: "It is clear that once the models are modified to represent new data and are reset to new current initial conditions that they will not show the 2 degrees by 2100 previously calculated. Let's hope the new models work better and at least get a better start than the last batch. Let's hope we can explain to the public in a rational way why we were wrong about 2 degrees. It just doesn't seem likely anymore let's face it sooner rather than later or the damage will be much worse if we let people like Hansen go out there and tell people we are 95% certain when we aren't. He is attacking science really by making such claims."
That is just arrant nonsense from someone who is perfectly obviously a total novice at the topic. It starts out by expressing considerable confidence ("it is clear that") and then concludes in the final sentence with an attack on scientists for telling people we are "95% confident".
That's inconsistent. Dare I say it… hypocritical.
It's also completely false. The claims for new data that conflict with the expectations of theory are blown up out of all reason. Stratospheric data? Totally consistent with models. Tropospheric data? Badly misrepresented by outright mathematical errors in one analysis, identified and corrected three years ago; and since then a matter of ongoing calibration and refinement, and always consistent with the models to within the available measurement errors. Ocean data? Systematic errors in one particular set of measurements a couple of years ago continue to be the basis for most skeptical arguments, which as always cherry pick the data and fail to keep up with the research. There are genuine outstanding issues with different ways of making the ocean measurements, with some measurements showing different results from others; but the discrepancy has been much reduced in recent years; with the plain identification and measurement of systematic errors in data that previously showed cooling.
The measurement and modeling of the ocean remains an open question; where we there is very likely to be useful model refinements. It has little credible prospect of "disproving" the basic conclusions of climate science in the way saturn suggests. Potential refinements are about resolving uncertainties, all within long since acknowledged and quantified bounds.
Whether we are "95% certain" on something depends on the particular question at issue. For the basic issues of anthropogenic warming, we are by now far more than 95% certain. The planet is warming, and the major cause of that in recent decades is an increased atmospheric greenhouse effect, and the major cause of that is human activity. You can take that to the bank as a straight scientific discovery. Sorting out the sensitivity of climate to forcings; and sorting out the magnitude of other secondary influences, remain open questions, but with nothing to match confusions of popular AGW-skepticism.
(5) There is no 2100 prediction: we have choices
There's a difference between prediction and projection. A projection makes certain necessary assumptions about crucial inputs that are NOT predicted. What we have is a number of alternative projections, all dependent on scenarios involving choices and alternatives that are not predicted at all, but remain open to us as real choices.
This is why the subject is not a science dispute also, but also a political one.
If humanity in general makes a concerted effort to limit greenhouse emissions by a combination of alternative energy sources, reduced demands, and mitigation strategies, then you have one set of likely outcomes. On the other hand, if humanity in general takes no particular account of greenhouse emissions and carries on with a carbon based energy supply for unmoderated demands and no mitigation, then you get a different scenario and a different set of likely outcomes. I expect we'll collectively choose for something in between these responses, but it's still a collective choice. Science tells you the range of outcomes in a given scenario, without a care for the political implications. Politics (hopefully!) makes choices based on costs and risks, which in turn has an impact on the scenarios for the future.
As well as the unknown of human choices; projections assume that the natural world is not going to throw a spanner in the works with some improbable random event, like an asteroid strike or a massive supervolcano. There is also the unknown of model uncertainty. Even given a specific set of assumptions about human activity and improbable random events, there is still a substantial range of uncertainty in predicted outcomes, of several degrees.
It is already the case, right now, that projections based on feasible mitigation strategies that would NOT bankrupt economies make it entirely likely that temperature rise by 2100 will be less than 2C; although such scenarios still include rises of more than 2C within the range of possibilities. For example, the "B1" scenario projects increases in the range 1.1C to 2.9C. This scenario, however, requires immediate political action and seems unlikely. The do-nothing scenarios "A1FI" imply increases in the range 2.4C to 6.4C, with about 4C as the best estimate. All numbers from Ch10 of IPCC 4AR.
The "A1B" scenario, which involves significant growth along with substantial commitment to mitigation and alternative energy sources, is still entirely plausible. Under this scenario, the scientific evidence indicates temperature increase by 2100 in the range 1.7C to 4.4C, with 2.8C as the best estimate. Rational risk analysis takes into account that we honestly don't know which end of the range is more likely, and prepares for both.
Head in the sand refusal to take account of the science, and which opts instead to be guided by pseudoscientific claptrap from discredited political hacks like Monckton, is profoundly irrational; genuinely dangerous, and unfortunately very common.
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Afterthought. This response is fairly general. I appreciate that saturn is not simply trusting Monckton; so not all the above is simply for saturn alone.
Even so, his comments here are simultaneously dismissing some pretty basic fundamentals while at the same time uncritically accepting as "almost certain" isolated work which doesn't even say what he claims. For instance, the German research team he mentions and which was recently published in Nature is almost certainly Keenlyside et al. They are attempting the very kind of specific prediction that saturn otherwise tends to say is impossible; yet here it suddenly becomes "almost certain". But Keenlyside's own statements on their own behalf don't say anything like that. They note explicitly that their ideas are uncertain and make certain simplifications and assumptions. Problems with those assumptions have been identified by other researchers in the discussion since publication. And finally, they DON'T just predict a slowdown: they also predict a SPEED UP in warming after 2010, to come up to a match with conventional expectations by 2025.
That's symptomatic of all saturn's argument, frankly.
Lindzen said
ReplyDelete"Roughly speaking, the warming at τ=1 in the tropics is from more than twice to about three times larger than near the surface regardless of the sensitivity of the particular model. This is, in fact, the signature (or fingerprint) of greenhouse warming. Stated somewhat differently, if we observe warming in the tropical upper troposphere, then the greenhouse contribution to warming at the surface should be between less than half and one third the warming seen in the upper troposphere"
This is regardless of sensitivity.
Good science encourages debate. Pseudo science discourages it. When I detect efforts to discourage discussion, I start doubting the intentions of those who discourage it. There is a political component to this science related to money and social control, which makes me skeptical of some of the more worst case scenarios.
Lindzen is the guy I am thinking of, more than any other, when I speak of maverick scientists who are an important part of the whole scientific enterprise. The word "contrarian" might have been invented for him; and that's not always a bad thing.
ReplyDeleteHe's a genuine expert; but he's also pretty much out on his lonesome on the whole issue. And that's okay.
The comment quoted above by pft sounds about right; except that I don't think it is precisely a greenhouse signature in particular. Solar forcing should warm the troposphere in much the same way, I think; the major difference between greenhouse warming and other forcings is higher up, in the stratosphere.
But the real issue with the troposphere is simply sorting out what the temperatures really are. There are several major difficulties. Radiosondes have systematic instrument errors that make historical reconstructions a bit dubious; satellite measures have the problem of pulling out the troposphere signal from the signal in the stratosphere.
This actually related pretty closely to the matter of "feedbacks", and most especially the "lapse rate feedback". As you rise through the troposphere, temperatures fall. This is "lapse rate". If the surface warms a bit, and the troposphere warms by a larger amount, then you have a weaker lapse rate, which is a negative feedback for sensitivity. (Counter-acted by the positive water vapour feedback, which is why net effect on sensitivity is limited, I think. Lapse rate is also associated with moisture and the moist adiabat.)
In any case, historical measurement of temperatures in the upper troposphere, and of lapse rate changes, are certainly vexed. This is by no means finished business so it is premature to declare victory... but recent work published by Sherwood and Allen in Nature Geoscience (Warming maximum in the tropical upper troposphere deduced from thermal winds; Nature Geoscience Vol 1, June 2008, pp 399-403) does point the way to the enhanced warming in the troposphere, as expected. There are still issues identified in that paper, however, so stay tuned.
0) DQ: nice analysis.
ReplyDelete1) How did this whole APS thing happen?
Catherine Brahic has a good story in New Scientist. Assuming this story is accurate:
You will find that APS Fellow, and frequent contributor to FPS Gerald Marsh suggested names to the (somewhat naive about this topic) editors, and only Monckton was interested in writing.
And if you look closer yet, you discover that for years, Marsh has been running an OpED / white paper anti-AGW campaign (but not in peer-reviewed journals). A partial list can be found RealClimate.
My take: the editors should have checked more, but they were effectively set up by a trusted source.
2) Numerous arguments would be seen as silly if everybody just understood:
a) The statistics of noisy time series, i.e., where the trend is masked by year-to-year and decadal-length jiggles.
With such, there *must* be series of years in which temperature flattens or even goes down, especially if one can cherry-pick.
Tamino, over at Open Mind has many good articles on such.
b) When the Earth has an incoming energy imbalance, *most* of extra energy goes, not into the atmosphere & land, but into heating the oceans, which are subject to ENSOs, PDOs, NAOs, etc. I.e., major jiggles. When air gets warm because of a big ENSO, nobody is disobeying the First Law of Thermodynamics.
See my version of the Bathtub Analogy at Atmoz.
Thinking one can ignore the oceans is like picking a handful of stocks, and thinking that by tracking them, one knows what's happening in the entire market. There is a good reason why climate scientists want 30-year winodws for real trends to merge from statistical noise.
We have pretty good measurements on some areas of land, we have satellites for the atmosphere, we have some on the sea surface, but *most* of the heat content isn't in any of those, and deeper ocean measurements are still sparse, although ARGO will help, as it gets better calibrated.
But still: if there's an energy imbalance, and the First Law still holds, the energy goes *somewhere*, and it's the ocean.
Let me try again. Whether its a difficult question or not, its one I don't know the answer to.
ReplyDeleteMWP was as warm as today, and was as much of a rise as today's rise. So why did it not lead to the further feedbacks? Why did not the subsequent rise in CO2 levels and water vapor lead to exactly the same temperature rises that are forecast by the IPCC?
And then, while I understand that at some point you run out of warming and the thing moves into equilibrium, why did it cool and not just stay stabilized at the new high temp?
And what caused it in the first place? It was presumably not CO2? So what was it?
What I am not understanding is why, if climate sensitivity is so great to fairly small variations in the past, previous rises do not seem to have provoked the rises that are now forecast.
I also don't understand what it was that is thought to have caused previous fairly dramatic warmings and coolings, and don't know how, if we cannot say why they happened, how we can be sure that the warming is not due to the same thing, and will not be followed by similar coolings.
The same feedbacks working today were working in the past as well. The temperature changes you see in the past were affected by feedbacks in the same way as temperature changes now are affected by feedbacks. Water evaporated then, as now, and this is the largest feedback. Ice melted, and froze, and reflected light then, as it does now. That's all feedback.
ReplyDeleteAlso, the energy balance of the Earth is constantly changing. There's no such thing as "stability" in the sense of absence of change.
Measuring the past is much harder than measuring the present. We know what is driving temperatures now, to a very high level of confidence, because we can study it directly right here and now, in multiple different ways. But for the past, measurements are indirect and very limited.
For questions about the past, there is evidence available to help indicate plausible answers; but it is obviously never going to be as clear cut as what happens right under our noses, so to speak. We don't really know for sure what caused the medieval warm period; though there are some good guesses. We don't know accurately how much warming was involved. We don't know to what it extent it was regional, and to what extent it was a global warming.
It seems likely that warming was greater around Europe than the rest of the planet; so in part the warming was regional. Most data suggests the medieval warm period involved temperatures comparable with earlier last century, but that we have since heated up beyond the MWP. Likely causes that may have been involved are land use changes, which alter albedo (the amount of light reflected as opposed to absorbed), or oscillations in the North Atlantic Circulation (which would make it more regional than global), or solar variation. Whatever the driving cause, feedback effects are always involved in the temperature response to that cause.
The reason why change in the MWP was (apparently) not as great, or as rapid, or as widespread, as in the present, is because the forces on climate were not as great as they are at present. Although climate sensitivity is remains quite uncertain (bounds given in my main blog post); we still have quite an accurate notion of how much radiative forcing has been applied in recent times by carbon dioxide increases. Other forcings in the present are less precisely known; but they are plainly smaller. There's no indication or any comparably large forcing at work in the Medieval Warm period; nor should we expect it, given that the changes were (apparently) smaller than at present.
Go back further in time and you can find some much large temperature changes; and in many cases we have a good idea of the causes at work in those times… a good example is the ice ages and the Milankovitch cycles of orbital forcings. Feedbacks are crucially involved then as well; and in fact be estimating the forcings involved based on inferred levels of ice cover and greenhouse gas concentrations from ice core data, we can get a rough estimate of the magnitude of feedback effects.
1) Via Milankovich, one would generally expected it to have been warmer earlier. We *should* be in the very long, slow downward jiggles towards anotehr cie age in 30,000? 50,000? years.
ReplyDelete2) While some of these are hypotheses, Ruddiman's "Plows, Plagues, and Petroleum", and better yet, his published papers, give some intriguing possibilities for some temperature jiggles. he jsut has a new paper out about additional evidence from China on rice paddies.
But later on, the Roman and MWP periods had minimal plagues, but the MWP had plagues on both sides of it. In particular, the Little Ice Age coincided with a huge die-off in America, in which many fields went back to trees, sequestering CO2. There is at least enough evidence to consider his hypotheses
Whether or not there is a signature of greenhouse effect in the troposphere is largely irrelevent. You seem to be falling for the trap so many others are also falling. The CO2 capture and release of IR energy is not really disputed. I don't think any "skeptics" really think that this doesn't happen. The question comes back again and again to the feedback because the CO2 capture by itself is not enough to warrant concern.
ReplyDeleteThe only way to justify all this science we are spending money on, the huge investments in satellites, ocean buoy systems and the billions in research is based on the idea of 2 degrees representing a catastrophic impact on the planet.
The problem and the point of my entire email is that the feedbacks are far far far less certain than the CO2 IR capture or even the sensitivity and direct forcing from CO2.
Because of this lack of certainty it is anti-science to adopt this holier than thou, everybody who is a skeptic just spouts satanic versus stuff that I see in so many websites. What I saw on your website was at least a modicum of what looked like trying to refute using real science Moncktons article and admitting where the weaknesses in the current science is.
I may be mistaken. Maybe you like Hansen have an agenda and you really aren't a scientist but more interested in the politics but the fact that you even entertained questions is very good, so I want to congratulate you on that and give you kudos and respect for that. I will continue to read your blog and website.
I am quite willing to accept that somehow the satellites and weather balloons have missed the tropospheric warming and that maybe wind or the lapse rate could be a proxy for tropospheric temperatures. I would say that by definition it is less sure than actual solid measurements but I understand that this might be hard to accomplish just as measuring temperatures on land has proven to be much harder than seems at first blush to be the case. Even Hansen seems to spend an inordinate amount of time correcting and correcting and correcting the land temperatures so they are accurate (hopefully) and he gets it wrong frequently as we have seen several times. That's not a subtle dig or something. I have no doubt that these thermometers have questionable accuracy and placement, etc... It is so exciting to get the ARGO data and see something that seems irrefutable data for once in this business. Ocean temperatures have gone down over 5 years. The heat signature is missing. I don't know how that could be wrong. These buoys are designed so meticulously and the measurements so frequent and well spaced. At least we have something (besides the satellites) where we can count on the data unlike all this historical debate of the MWP.
What I've seen that seems rock solid on this topic is records from written archives which show that people did colonize and grow food in Greenland. It was much warmer there than it is even today. There is archeological data to back this up too. Also, there is indisputable information on the little ice age. Written accounts of the Thames freezing over and fairs with people having barbecues on the ice to me is very convincing. Of course nobody knows for sure if those conditions existed outside of northern europe. So, once again into the breach of we don't know.
It seems to me that everytime the data supports one side the other side says the data is bogus and everytime the data supports the other side then the counter side says that data is bogus. I don't believe your claim there is a "smart good" side and an "evil stupid" side. I think everyone is working to the same goal which is the truth and calling people names is unhelpful. On the other hand some people are clearly unscientific. I would say that people who ascribe more certainty to things than is possible or likely are just as unscientific as those who don't.
Getting back to the point. The issue in my mind that is most important is the feedbacks. It seems indisputable to me and I've seen nothing you've written which counters this argument of Monckton and others that the feedback is way way less than the IPCC calculated in all their AR1-4 reports. The feedback might even be negative to the point that the effect of CO2 is almost totally cancelled. I don't believe we have the answer on that.
The main argument for positive feedbacks is based on models. Models which I believe I have demolished pretty well and I think cannot be defended. My argument is not that AGW doesn't exist or that the feedbacks might be huge. My argument is more that we simply don't know and anything we say is really at this point no better than random guessing. The temperature in 2100 or with a doubling of CO2 could be +13 or -10 degrees from today or anywhere in between. In my opinion "real" scientists need to say this to the general public in no uncertain terms or all science will be in for a massive shock when the truth comes out that we don't know and didn't really know and lied to them or deceived the public at great cost to the world and for our economic benefit because we got research bucks or invested in companies based on hyped theories we knew were not as solid as we said.
I, like previous writers question how good the models work whether we are talking about the MWP, ice ages in the past or current temperatures. Until we can explain the last 10 years haitus in temperatures (what you call "wiggle") we have no confidence in the models.
Why? Because the models first predictions were in 2001 (I am excluding the 1990 models but we can go into that). These models seem to understand most of the wiggles up to 2000 pretty well. I was impressed to some extent even if I've said it is trivial to build models which mimic any set of data trivially. I want to believe the models could work eventually (even with my intense skepticism) but what breaks the kneecaps of these models is that they immediately failed to match in any way the past 8 years. Not just failed to predict land temperatures but the whole array of data from the ocean to higher in the atmosphere.
Again, I have to discount (as any real scientist has to discount) the models accuracy on past data. Not only is the data itself suspect that is being fitted to but any mathemetician can build an infinite number of models which match to any degree of precision required a past set of data. This is not at all impressive. I'm sorry. All that matters is what you predict when we don't model it and what happens and the jury is out on that at best because the models have failed. They all predicted a warming trend that has not materialized in the oceans, land or air since 2001 since they were issued. That is simply damning. No amount of excuse gets around this and the only way to get back confidence is to make the models work better or to explain the last 10 years like we have used volcanoes in the past to understand temperature declines and particulates.
All the models show for instance that both the north and south poles should show MORE warming than at the equator. This is true of the north pole. It's not true of the south pole. What we seem to have is "north pole warming" not global warming. In fact I wonder if you factor out the north pole from the data how much warming is actually left in the system at all!! If you look at data for the US we haven't warmed very much. The temperature pattern of a warmer NORTH pole is better explained by the NAO and PDO phenomenon not greenhouse gas emissions. Of course why do we have NAO and PDO? Maybe that is becuase of CO2. I haven't seen someone link these effects to CO2 yet. That would be useful because then it would explain why these 2 phenomenon are going to collapse suddenly over the next 100 years and we're going to get just consistent warming till 2100 as we increase CO2. (even though we have increased CO2 10% in 10 years and seen no increase in temperatures)
You have to admit the data must give you pause. You are constantly having to get into a defensive posture to explain why the data don't conform. The reasons keep coming out: well, it's normal, it's just statisitical noise, it really is happening if you look at it this way, it will happen I promise you. It does seem that you and the defenders of AGW hysteria are in the same position as skeptics were a few years ago when temperatures were going up. Better publications and more PHDs doesn't cut it because people are more impressed with results than excuses.
In my opinion science is the big loser here unless we can drastically improve the models correspondence to actual data and these models can explain things like the last 10 years and maybe the MWP and NAO and PDO, the lack of ocean warming, the lack of antarctic warming and maybe the lack of sufficient tropics tropospheric warmth.
My concern is the future of science and are we being good scientists. I think the pushing of a political agenda in science by the left or right is evil and that is really what I am against.
Hello, thanks for your explanations and for your comparative lack of arrogance compared with a forum like realclimate - it gives a newcomer like me the courage to dip my toe in the water.
ReplyDeleteFirst, regarding something Monckton said towards the end of his "Discussion" section:
"It is of no little significance that the IPCC’s value for the coefficient in the CO2 forcing equation depends on only one paper in the literature; that its values for the feedbacks that it believes account for two-thirds of humankind’s effect on global temperatures are likewise taken from only one paper; and that its implicit value of the crucial parameter κ depends upon only two papers, one of which had been written by a lead author of the chapter in question, and neither of which provides any theoretical or empirical justification for a value as high as that which the IPCC adopted."
Is this correct? If not, do you have a link to any rebuttal of this point?
Second, your query about the origin of the figure of 1/3.2 for κ. Has anyone gotten back to you? Am I right in thinking that the selection of this value rather than 1/3.7 will tend to increase the feedback values and therefore increase the warming estimates derived from the IPCC's models compared with a value of 1/3.7?
Finally, thanks for your analogy of the guitar/amp for climate sensitivity. While I realise analogies are no substitute for argument, they can be a very helpful tool for specialists in a subject area to explain a concept to laymen, provided everyone is aware that any analogy will ultimately break down (as I am). My take on the debate about climate sensitivity, using your analogy, is that CO2 is like the guitar and climate sensitivity is like the volume setting on the amp. The resulting overall sound level is the level of warming. People like Monckton would say the amp volume dial is set at negative one (warning: analogy breakdown!), or Spencer or Lindzen would say it's about positive one, IPCC would say it's about six, realclimate would say it's about seven and Gore would say it's eleven (apologies to Spinal Tap). The real point is that these are guesses (some educated, some less so) and that no one at this stage (given where the science is at) can say for sure. Is this a fair layman's take on the climate sensitivity debate?
On the MWP and feedback, there seems to be an error or at least a gap in logic.
ReplyDeleteWe've two facts: one is the rise in temperatures from 1975 to 2005. The second is the MWP. I take the references on CO2 Science to show that this was really global, and think we've no reason to think it lower than today. Some to think it higher.
The question we are tryng to answer is whether the present warming has been shown to be caused by a combination of CO2 warming and associated feedbacks, and whether there is evidence that this warming will continue. Or, could it have been caused by something else, for example the thing that caused the MWP, and be about to be succeeded by cooling, of the sort that succeeded the MWP.
I don't see how we are to tell on the evidence to hand. We don't know whether this warming is particularly unusual. The thing that is unusual is what is forecast to be about to happen, but that not having happened yet, is not evidence. We do have one thing which is clearly different: rising CO2 levels. But its not clear how we have proved causation. Yes, we have two things happening at the same time, the temps have risen from 1975+, and CO2 levels have also risen. But how do we know that this is not coincidence? How do we know that the same thing that caused MWP has not caused this warming, and that this has coincided with a rise in CO2?
This may seem simply ridiculous to suppose. The argument seems to be that there is nothing else to account for it. But there is: whatever caused the MWP. As long as we have no idea what that was, the argument that only CO2 emissions can be causing a temperature rise is not compelling. It is rather similar to arguing that nothing else could account for the diversity and adaptedness of creation to the planet save the existence of a creator. It is always very hard to argue from the fact that we have no idea what else a cause can be, to this being the cause. Very often such things are exactly what gets overturned by later scientific advances.
It must be possible that rising CO2 levels would provoke rising temperatures which would by feedbacks lead to the kind of warming forecast by AGW. But I don't see the evidence. The significance of the MWP is that it shows temperatures can rise this much in other ways and from other reasons.
Your reply seems to be that the MWP, despite being as large as the present warming, did not provoke the rise that is forecast to result from the present warming. The reason is that the forcings were not as great as today's. But that is circular. The evidence we have for the forcings being lower is that the later warming did not happen.
What I'd like to see is independent evidence covering the level of forcing from the two warm periods we know of - RWP and MWP. Then, it would also be necessary to have an account of the two coolings we know of in historical times, the cooling period after the RWP, and the LIA. If we could get an account of what caused them, we could assess whether they are likely to happen again. This would tell us whether the forecast for renewed warming is likely to be true, or whether we may start to see a similar cyclical cooling.
Its important. There is no chance we are going to stop the ROW from emitting ever increasing amounts of CO2. So it is really important to get to the bottom of what this is going to do, if anything. For me this is not about US or EC policy on CO2 so much as about what is coming towards us, given the probable way humans are going to behave for the next 20-30 years.
To extend the guitar analogy even more. There are 2 volume controls. One on the guitar and one on the amp. I think Monckton is saying that the guitar amp is set at close to one, not negative 1. He is also saying that the guitars volume is set down to 1/3 of its maximum. He makes this argument based on the idea that the tropospheric warming is substantially less than predicted therefore saying the forcing from CO2 is 1/3 what the IPCC said and therefore that says the guitars volume is set low and then he argues in addition that the guitar amp is also turned down. This is why we hear so little sound. Whereas others are saying the guitars volume is set high and the amps volume is low. Others are saying the music is loud and clear and don't understand why nobody seems to hear it.
ReplyDeleteI haven't heard many people argue since 1998 that the guitar volume itself is set at 0 or that the guitar amps volume is set at -1 but with the lack of heat for 10 years and the lack of conformance of the IPCCs predictions on polar warming at the south pole, the tropospheric data problem, the now 10 or 11 year (probably at least 15 or 20 year if the germans are correct) land temperature variance, the 5 year drop in ocean temperature we are left with what appears to me to be a trifecta of unambiguous flaw in the models of global warming and how it should play out. This then makes the argument viable again that the volume is set to 0 on the guitar or the amps volume is indeed -1.
My argument is that unless the guitar is turned all the way up and the amps volume is set at least at 3 then nobody is coming to listen to the music. The alarmists have put in stone that at 2 degrees we have calamity and below 2 we don't. Many researchers and companies trying to milk money off this hysteria NEED a guitar volume turned all the way up and a amp volume of at least 3 or the monetary motivation drops off totally. So, it is clear why many scientists and corporations now tout a high amp volume even though the emperor isn't wearing any clothes. they need the volumes to be turned up very high or they know the crowd is going to go away. So, they proclaim the sound is fine and don't anybody leave the theatre. The guitarist is screaming he has his volume set as high as it will go.
It appears that some scientists (Hansen, Gavin) are running around screaming about how high the volume is and how they can barely hear each other through the loud noise from the amps and yet most people today are walking around the concert hall hearing the chirping of the cockroaches and very little sound wondering what the fuss is about.
Other scientists are running around saying the lack of sound now is because the guitarist is playing softly and you remember the warmup band sounded fine. However, we know this song and it doesn't sound like this is the soft section of the music. Nobody seems to be able to get up and see what the amp volume is set at or if the connections to the amps are solid.
I am assuming the guitarist has his volume set high. I believe the guitarist proclomations he's not the problem and I think most people agree that CO2 does cause warming and the guitarist has his volume set high. Although it is troubling that there is no sound coming from the speakers and the guitarist does sometimes drink a lot. We had the guitarists ditzy girlfriend go up and talk to the guitarist but we're not sure about her sobriety or knowledge of things guitarish. So, there is some doubt about the guitar volume level.
On the other hand I say we don't know the value of the amp volume at all. Nobody really has looked at the amp volume or the connections to the amp. That could be the problem. Maybe someone stuck an attenuator somewhere in the circuit. We don't know because nobody can actually see any of this complicated stuff past the guitar.
The problem for the concertgoers is that they paid for the concert, they paid for scientists and politicians to implement vast expensive policies to have this concert and now there is no music coming out of the speakers or sometimes you hear something, a squeak. You know people are going to be mad. They are going to lose faith in the musicians or the hall and never come to the concert again or demand some kind of refund. That means science will suffer.
Welcome aboard, Skut!
ReplyDeleteI suspect the big difference between here and realclimate is that my blog is a far smaller and less well known. Big blogs attract lots of people, and that alters the dynamic. I love realclimate; but hey! I'm delighted my own two cents backwater is meeting a few needs as well! Thanks.
I think Monckton is incorrect about important parameters being given in only one paper. I've read a number of papers myself as I've been studying the subject, which give a base feedback parameter value in about the same range (3.1 to 3.3 or so), based on their own calculations. It's really a diagnostic number for a climate model; and since models are all based on physics, they all tend to give the same result for the base temperature response when everything else is held fixed.
However, when a paper is not providing its own calculation, then it is normal to cite one or other of a couple of major papers; usually Soden and Held; itself a review of many other results. The line-by-line calculation of CO2 forcing seems to be done by lots of people as well; but usually cited to the pioneering work of Myhre et al. This is not because these are the only guys who calculate it; but because these references stand out as pioneering in some way, I think.
As for 3.7 or 3.2… I don't think this choice is what determines results. Rather, the number 3.2 is used as a simple diagnostic of the results that actually are obtained, by a bit of analysis of results. This diagnostic number varies a little bit between models; but not by much.
I have had some comment from Gavin over at realclimate, but I was not satisfied. This is more a reflection of the fact I'm still struggling to understand; not a suggestion that Gavin is wrong... I may not have understood him completely. But I have a sneaking feeling in the back of my mind that perhaps the temperature change applied is not quite as vertically uniform as he says. You can see my comment, and Gavin's inline response, in a realclimate comment, here and here.
One day I might write up my two methods more thoroughly, and post it by snail mail to Gavin, and ask him to tell where I'm going wrong again. I still have a sneaking feeling that the vertical temperature change is not quite as completely uniform as Gavin's inline replies suggest. Presumptuous of me; but there you go. I've tried to integrate over latitudes, and the only way I get close to 3.2 or 3.3 is by allowing a slight vertical non-uniformity, which falls out naturally in any case by using a simple sequence of slabs for the atmosphere all with a small fixed emissivity.
As for sensitivity; there are half a dozen different ways to characterize sensitivity, which makes it confusing. In my blog post, Monckton uses a number "b". Another very common number used is the temperature rise for doubling of CO2, and if you look through the post carefully, you'll see this can be related to "b" as T_2 = 3.7/(3.2-b). Since "b" is feedback, the "gain" can be thought of as a ratio 3.2/(3.2-b).
Monckton does not really give a clear number; but Roy Spencer proposes "b" as -0.7, and uses 3.3 as κ. The IPCC uses 3.2, and "b" in roughly the range 1.4 to 2.4; centering on 1.9. Realclimate is has a particular big input from Gavin Schmidt. His GISS ER model has values 3.24 and 1.6; it was one of the inputs to the IPCC combined estimates. I don't know much about Gore, frankly; but I gather his proposals are all pretty much IPCC.
The state of play, as I read it, is that the IPCC value is the most sensible one to consider; it is not a single value, but a range of values and an idea of uncertainity. Readclimate tends to report IPCC results, but a major contributor there, Gavin, also stands as one of the data points used in the IPCC; so he is an example of a specific estimate; and he is actually a significantly low end of the sensitivity proposals. So in your summary, you need to exchange the places for realclimate and the IPCC. Gore does not, as far as I know, propose anything wildly different, but I can't really say. Monckton is more a less a lunatic; and his numbers correspond to roughly 4.13 and 2.16; but he also reduces the forcing 3.7 to 3.4 and then reduced by a factor of 3. Silly… in fact, the forcing is the one value we know to considerable accuracy. Spencer uses 3.3 and -0.7.
As the temperature sensitivity to a doubling of CO2, these values are:
IPCC: 2 to 4.5
Gavin: 2.25
Monckton: 0.6
Spencer: 0.8
You may safely dismiss the numbers from Spencer, and from Monckton, as frivolous and unphysical.
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John Mashey, I've read some of Ruddiman's stuff; very interesting. But it seems to me that there's a conflict between Ruddiman's work and the notion that the current interglacial is likely to be a long one. As I understand it, the Milankovitch style analysis suggests the Holocene will continue for many thousands of years yet, even in the absence of any human input. But Ruddiman considers that the ice age decline has already started; and is being offset by some greenhouse forcing from land use changes. The work suggesting that the current interglacial should normally be a fairly long one seems pretty persuasive to me, and a bit of a knock for Ruddiman. (Ref: A. Berger and M. F. Loutre, "An Exceptionally Long Interglacial Ahead?", in Science 23 Aug 2002, Vol. 297. no. 5585, pp. 1287-1288.)
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Anonymous; the general state of research on MWP is that temperatures were less than the present, that the change was not uniform over the globe but was particularly strong in Europe. There's some variance of opinion on this, but co2science represents a very extreme perspective, in conflict with most paleoclimate research. I can't follow what you mean by "did not provoke the rise". I'm not being circular; I'm just going by best current estimates for the amount of temperature rise involved. It seems to be less than today, and more limited in scope as well. Most certainly it was all more gradual. Now study of past climate is uncertain, of course. But that's the way evidence is leaning at present, co2science notwithstanding. There's little point asking for data about the forcing in the MWP; I don't think that can be measured in any credible way. There are guesses about the solar forcings; but this is much less certain than temperature. Basically, if the temperature rise was less than today, then the forcing was probably less as well. If the temperature rise was greater, then the forcing was probably greater also. The temperature is really our best guide to the forcing involved, whatever it was; and even then we need to know sensitivity to put numbers on it.
Projecting what is likely in the future is difficult! As you note. But the best way to resolve that is likely to be continued improvements in climate modeling, which is really about applying physics to the problem. Another proactive approach involves working towards reduced human impacts generally. Just switching off emissions is neither possible nor desirable, but there's still lots of scope for realistic human choices to make a difference.
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Saturn, the guitar is just an analogy. You can't push it too hard; the poor thing will break.
DQ:
ReplyDelete1) I assume you've seen the 2005 guest post & discussions by Ruddiman over in RealClimate.
2) Also, it's worth reviewing Figures 14.1 and 14.2, and relevant text in the book.
I think that there is sometimes confusion around all this, in that "imminent" glaciation can mean, at extremes:
a) Chicago gets covered with ice tomorrow.
TO
b) On Baffin Island, a small ice-cap whose southern limit has been jiggling around with no trend develops a trend in which it averages about .1mile/year further south ... which would get it to Chicago in 20,000 years.
Put another way, at least for some, glaciation means that the size of ice is increasing, but that says nothing about the rate...
It is often the case that "imminent" to a paleoclimatologist means something different than to most of us :-)
In any case, all of these are still hypotheses. One of the reasons I admire Ruddiman's work is that he is very careful about distinctions between "hypothesis" and "theory", and clearly, this is still being argued.
3) You might want to look at the following, if you haven't already:
"The Early Anthropogenic hypothesis: Challenges and Responses", Reviews of Geophysics 45, 2007: here, which discusses the Loutre/Berger issues in detail.
Thanks for the pointers, John. Here's a link to the realclimate discussion of 2005, which I had not seen before: Debate over the Early Anthropogenic Hypothesis. I'll leave it at that. Ruddiman does a pretty good job, it appears, of laying out the alternatives.
ReplyDeleteDuae, another damning article has appeared in hydrological scientific publication analyzing model outputs against real world data showing of course (drumroll please) no correspondence or correlation between model predictions and reality.
ReplyDeletehttp://www.atypon-link.com/IAHS/doi/pdf/10.1623/
They tested 8 different locations and applied numerous scenarios all showing that the models did worse statistically than a simple "average". How embarassing. All that work and an "average" beats them.
I can point you to other papers (peer reviewed) which have attempted to also replicate model results against the real world. All have failed miserably. The authors seemed shocked in fact at how badly the models do.
As I've said repeatedly it is not at all surprising. In fact it confounds me how anybody had ANY faith in these models who has even a modicum of computer science, mathematics, statistics or chaos theory knowledge.
It is illustrative that the APS chair didn't even bother to include an article defending the models. The paper put into the newletter to defend the AGW hypothesis simply stated what everyone admits. The physics of CO2 heat capture is not disputed. What is disputed is how that manifests itself in the real world.
Monckton provides a spirited defense of his use of various calculations in:
http://scienceandpublicpolicy.org/images/stories/papers/monckton/monckton_rebutted.pdf
It is interesting to me that in Smiths attack on Monckton he mentions that the APS paper used as a contrary to Monchton in fact to be more spirited attack on global warming that Monckton himself gave since it does not defend any level of feedback it leaves the total AGW effect at about 1.2 degrees or less, in fact the paper refuses to even give a temperature change for the forcing it calculates thereby leaving the sensitivity discussion open to debate. It seems that these 2 authors are not willing to say that the temperature variation from a certain forcing is something that can be defended scientifically.
Given the quite impressive defense by Monckton of his assumptions and reasons for his cutting by a factor of 3 both the temperature sensitivity and the feedback it is hard to see how to argue against him. It is plain that nobody wants to step into the "s***field" that is the feedback debate. Neither the APS nor Smith nor you seem to want to defend the feedback calculations in the models. Moncktons argument on the forcing value being cut in 1/3 is simply that since the temperature change is ultimately a multiplication of 3 variables it really makes no difference where one puts the 1/3 factor. Call it a feedback or lack of sensitivity or forcing. While not convincing it is mathematically correct.
Smith in HIS attack on Monckton does attempt to defend the models by bringing up a chart showing how a logarithmic map of CO2 multiplied by various sensitivity values results in a "best fit" around 2 degrees for each doubling of CO2. This is to my mind a more sensible way to look at the problem than models. So, I give him credit for that. However, Smith makes the assumption that ALL heat in the system is being generated by CO2 or other GHG. This is an assumption since we don't know what caused the little ice age or MWP or other multi-decadal oscillations we have no idea if those factors are contributing to the warming since 1850. What we have is a naive analysis by Smith that presumes that if CO2 is the sole reason for warming since 1850 then it makes sense that the sensitivity is 2.0K / doubling of CO2. As I've said before such naive curve fitting is absurd. Any number of similar "relations" could be created for any number of inputs including walnut production over the last century. Maybe walnuts increase temperatures too? Who knows? This is so un-rigorous to assume that any one variable is responsible for something like climate when it is clearly much more complicated. Until the models can show conformance to past temperature patterns and explain things better it is impossible to believe that CO2 is the sole factor affecting temperature over periods of 50 or 100 years. We just have too many oscillations like the little ice age that can't be explained by this simple model yet the more complicated models don't do it either from what I've seen.
I continue to be convinced the PDO and NAO or AMO are more reliable predictors than the models. Since they show a 25-30 year haitus in temperature rises and a drop in arctic temperatures we will soon see which works better. I would like to see the models be able to predict la Nina and El Nino phenomenon to have more confidence in them. These phenomenon are clearly significant energy weather patterns that should have some modeling capability. The energy has to come somewhere for these huge phenomenon. Similarly the models should be able to explain larger scale phenomenon like PDO and NAO. improvements of this magnitude in the models abilities would go a long way to believing they really understand what is going on in the atmosphere and how energy is moving around in the system.
My point continues to be that the feedbacks are simply unknown. Since the majority (2/3rds) of the temperature change is assumed to come from feedbacks that are completely uncertain, unprovable and seem to be very suspect in terms of the real world it is impossible as a scientist to ascribe any probability to things like a 2.0 degree increase from a doubling of CO2.
It is also rarely pointed out that when the IPCC and others talk of a doubling of CO2 they almost always mean a doubling from the 270 or so that was common in the 18th century before the industrial revolution took hold. Since we have had nearly a degree movement in this 150 years it means we have only 1 degree to go for the rest of the century assuming that we do in fact double CO2 to 550ppm or so. As you know the effect of CO2 is logarithmic so we have already seen a substantial amount of the warming we are going to get from the doubling which further mitigates the argument we will get 2 degrees by 2100.
I am so depressed about all this because what I see is something so obvious and I don't understand why we as scientists can't agree on something as clear and simple as the fact that the models cannot possibly have the same precision as the CO2 forcing (which is not 100% certain either - but I grant it anyway to facilitate the point). As I keep saying since 2/3 of the warming is predicated on this absurd model approach it is impossible for anybody of science (i.e., Hansen, Gavin) to proclaim such assuredness about these models and their predictions. Given the numerous studies now which show the models grotesquely bad predictive ability, given the lack of conformance for the last 10 years of the models to reality, given the very high liklihood of continuing cool temperatures for at least 5 years (the german paper) which I believe is intuitively obvious given the cool ocean temperatures it is all but assured that the 2 degree for a doubling of CO2 will transpire. Further, since a 2 degree total sensitivity only gives us 1 degree additional warming before 2100 the whole framework of climate catastrophe collapses (even if one believes the absurd predictions of starvation, etc..)
This issue is dead. I just can't see how anyone can defend AGW being a significant issue for us to worry about even with current trends in CO2 production in the next century given how temperatures have behaved in the last 10 years in the ocean, on the land and in the troposphere. It seems incredibly unlikely to me that temperatures will just start spiking and "catch up" as the germans seem to think. I don't believe the NAO and PDO phenomenon just disappear and we go into some super accelerated heat spike given that the heat in the ocean seems to be non-existant and in the sky. The oceans have 300 times the heat capacity of the entire atmosphere. If they are cooling it makes the probability of a warmer atmosphere extremely unlikely in my opinion. How would you explain how temperatures are going to spike while the ocean seems so uncooperative?
I feel science will be damaged by this. I feel it is already damaged because of a strongly perceived bias and hype that is financially motivated by scientists and politicians trying to take advantage of a gullible public.
Saturn's first link (refer his recent post) appears to be busted. Try this:
ReplyDeletehttp://www.atypon-link.com/IAHS/doi/pdf/10.1623/hysj.53.4.671
Hi DQ
ReplyDeleteExtraordinarily, the Earth has enabled life as we know it to have evolved. And so far we have not succeeded in finding the necessary concatenation of improbabilities occurring elsewhere in the universe. The long term environmental stability required by evolution and sustained over billions of years has a number of contributory factors (for example vast quantities of water consistently in the liquid temperature range and a nearly circular orbit around the parent star).
Among these altogether unexpected conditions are the Earth´s axis maintaining an interesting constant tilt relative to the sun (just about a quarter of a right-angle) as well as continuously spinning on this axis every 24 hours during its journeys round the Sun.
My simple question is: how do the IPCC´s Climate Projection models take into account these particular values of the Earth´s tilt and rotation?
Related to the last post I have always been confused how a 1% variation in solar radiation is treated as insignificant and yet a 0.03% change in CO2 concentration in the atmosphere will cause MASSIVE change in temperatures and life on the planet.
ReplyDeleteHow much change in total solar radiation occurs because of the milankovitch cycles anyway? 1%, 5%? These are supposedly responsible for plunging us into ice ages that cover the globe with massive sheets of ice all year or turning the planet into a tropical paradise where ocean temperatures in Hawaii are 98 degrees fahrenheit.
Is it possible that magnetic storms associated with sunspots could affect the magnetosphere of the earth in such a way to add energy or cause a large impact on climate? Could these magnetic storms cause energy in the internal parts of the earth or produce energy somehow? It seems intuitively obvious that a changing magnetic field "rubbing" against ours would produce some kind of residual energy that might not be detected as "solar radiation" and still produce heat on our earth in some indirect way possibly heating the oceans for instance through increased heat under the surface of the earth. I have never seen anyone discuss this or the physics around this.
Anonymous, climate models do take into account changes in tilt and other orbit factors, but only when doing a very long term simulation, appropriate for trying to describe changes over long periods of time in the past. For the next hundred years, there's no big changes likely so models just use current tilt and rotation.
ReplyDelete----
saturn, your numbers are wildly incorrect.
The change in CO2 is not 0.03%, but over 30%. This is measured. CO2 has gone up from 280ppm pre-industry to 385ppm now; and that is about a 37% increase.
A 1% change in the Sun would be massively disruptive; but fortunately the Sun is far more constant than this. The Sun has brightened by roughly 0.2% since the Maunder minimum; and in the last 50 years it has been almost constant.
You can calculate the forcings for these changes quite easily. The effect of a 35% increase in CO2 is about 1.6 W/m^2. The effect of 0.2% more Sun is about 0.5 W/m^2.
In the first half of the twentieth century, variation in the Sun probably had an impact about comparable with greenhouse changes. But in the latter half of the twentieth century, the greenhouse effect has accelerated, while the Sun has remained steady. So for increasing temperatures seen over recent decades, the Sun is not a big factor. The recent warming trend has been mostly driven by greenhouse changes.
Milankovitch cycles don't make much difference to total solar input at all. What they actually do is alter the seasonal differences. An ice age seems to be associated with a larger difference between winter and summer. For example, as Earth's orbit becomes more elliptical, winter in the Northern hemisphere becomes a bit longer; while summer is a bit shorter. This triggers changes in ice cover, and it is actually the effect of ice reflecting light which affects temperatures most. To this is added a greenhouse feedback and also other surface albedo changes. The solar variation from Milankovitch cycles is much too small to account for ice age temperature shifts all by itself; the temperature change actually comes mostly from positive feedbacks involving albedo and greenhouse effects. Or so present evidence indicates.
Magnetic storms have only a negligible effect. The actual energy involved is tiny, so any effect would have to be indirect. There is some indication that they can alter ozone production, which leads to a small effect, and this IS studied.
There is no "physics" to discuss here. It's a wild speculation, with no credible physical basis for any ocean heating, and perfectly obviously a total non-issue when you look at measurements of temperature and the magnetosphere. No connection, no reason to think there is a connection.
There is, on the other hand, a straightforward bit of thermodynamics which says large increases in greenhouse gases have a big effect. The physics here is unambiguous.
Basically, you are in the position of having a rottweiler chewing on your leg, and wondering if perhaps a vitamin deficiency might explain why it hurts. :-)
> saturn, your numbers are wildly incorrect. The change in CO2 is not 0.03%, but over 30%. This is measured. CO2 has gone up from 280ppm pre-industry to 385ppm now; and that is about a 37% increase.
ReplyDeleteAgreed but the number I was referring to was the total percentage of our atmosphere. CO2 has gone from 0.028 percent to the year 2100 where it will theoretically be at 0.058 percent of our atmosphere. That is a 0.03% increase as I stated. The appropriate analogy would be for us to have 1 grain of salt in boiling freshwater and you add 1 grain of salt more and expect the water to stop boiling. True enough the salt content of the water jumped by 100% but an extra grain of salt isn't going to make a pot of water stop boiling even if it is a 100% increase in salt. It is hard to imagine that increasing any component of our atmosphere by 0.03% is going to cause massive changes in the environment considering the amount of atmospheric change sustained by this planet over time.
> A 1% change in the Sun would be massively disruptive; but fortunately the Sun is far more constant than this. The Sun has brightened by roughly 0.2% since the Maunder minimum; and in the last 50 years it has been almost constant. You can calculate the forcings for these changes quite easily. The effect of a 35% increase in CO2 is about 1.6 W/m^2. The effect of 0.2% more Sun is about 0.5 W/m^2.
From https://www.blogger.com/comment.g?blogID=879226427561095229&postID=704662321851102680 I quote: We might expect solar variations of 0.2% are possible since that is twice the present 11-year solar variation.The 0.2% variation gives a surface temperature variation of
ΔTs = Ts(Δs/so)/4 = (287 K)(2 x 10–3)/4 = 0.14 K.
So, we have a forcing from solar variability that is about 1/3 to 1/4 what we have from a doubling of CO2 but it's not insignificant especially if CO2 turns out to be cancelled by strongly negative feedbacks. Of course the solar variability would probably also be cancelled by those same feedbacks unless the negative feedback was specific to CO2.
I also notice that you can only ascribe 0.6K to CO2 which is insufficient to get anyone worried. This is my central point of course. Without "postulated unproven" feedbacks you, Smith, APS nobody can scientifically prove we have sensitivity >0.6 degrees to a doubling of CO2. This is the central problem with the whole AGW is "settled". Yes, everyone agrees we might get 0.6 degrees in the 21st century. So what? The IPCC said 2 degrees but nobody can prove anything over 0.6 and the mere fact that the APS did not publish an article defending any level of temperature rise (even 0.6C) says that this is scientifically unsupportable.
> The solar variation from Milankovitch cycles is much too small to account for ice age temperature shifts all by itself; the temperature change actually comes mostly from positive feedbacks involving albedo and greenhouse effects. Or so present evidence indicates.
Thanks for that. Been searching for that for a while.
> Magnetic storms have only a negligible effect. The actual energy involved is tiny, so any effect would have to be indirect. There is some indication that they can alter ozone production, which leads to a small effect, and this IS studied.
Thanks again. Wonder how that ties into the drop in Ozone that seems to be causing the chemical changes in the froth of the ocean which is eating the methane in the pacific? Is this what is being studied?
> Basically, you are in the position of having a rottweiler chewing on your leg, and wondering if perhaps a vitamin deficiency might explain why it hurts. :-)
Well, I understand your analogy and appreciate what you are trying to say but I tend to look at such comments as disturbingly funny because they are so out of kilter to what is really happening. We aren't having a rotweiler chewing our leg. Frankly, temperatures haven't moved in a decade and we're actually in a cold spell so the analogy seems over-weighted. Also, we've since proven that storms are not increasing and Bangladesh's land mass is actually increasing etc... so it's hard to see there are ANY negative effects happening or will happen from global warming even assuming it happens. That's one of my problems with all the reporting as well. This completely outsized angst about the effects of global warming is bizarre.
The use of biofuels is causing a demand on the food supply that puts 1,000,000,000 people's lives at risk. The gains against poverty of the last 20-30 years are being demolished by high oil prices caused in part by an unwillingness to build more nuclear and other energy sources as well as these food price increases. The rottweiler in my opinion is not temperature increases (which aren't occurring anymore) but not getting enough energy in general that is leading to a potential loss of life that dwarfs anything ever imagined by global warming for 200 years.
I don't want to get negative though. I appreciate very much answering my questions above but I would ask you to consider if maybe the surety of 2 or 3 degree sensitivity is warranted when you can only show 0.6 certainty and when the claims of "armageddon" seem so misplaced with reality. Armageddon is more likely if we don't get food prices back in line and get energy prices down not some theoretical imagined sensitivity of 2-4 degrees to CO2 doubling and the ridiculous "effects" that you try to refer to by saying our leg is being eaten by a rottweiler. We are actually doing quite fine on the weather front. Hurricanes are down. It's pretty much business as usual. Death rates from natural disasters are the fastest FALLING cause of death in the last century.
As a simple example of this. France had 15,000 people die from the heat wave a few years ago. Since then other heat waves just as severe have hit France but the death rate was in the single digits (i.e. <10). For a negligible amount heat deaths were reduced by >99%. Our ability to deal with natural disasters is probably the thing that distinguishes our modern technology more than anything else. 1,000,000 people died per year from natural disasters in the early 20th century. Over the last decade or so that death rate has fallen to 20,000 people per year and that is with 3 times the population of 1900. That is a 99% reduction in death rates. We are amazingly good at dealing with things natural disasters and we continue to improve our ability to mitigate, predict, plan and deal with these disasters. The article this morning on Bangladesh gaining land points out the ridiculous and completely outsized hype generated about the supposed effects of global warming. Yet in the meantime 1 billion people's lives are at risk because we tried to stop global warming with bio-fuels. I just ask you and others to consider if you are overplaying this "rottweiler" analogy. I guess my argument would be that the rottweiler would be biofuels sucking up our food supply and global warming being the vitamin pills. Yes, the vitamin pills are good for us long term maybe (although the evidence is thin on this sometimes) but the rottweiler (the food supply being burnt for oil to reduce CO2 output) is about to kill 1,000,000,000 people.
Thanks for clearing up the physics on the magnetic stuff. I'd like to see more of the numbers because somehow these magnetic storms seem quite massive. I have heard descriptions that each sunspot explosion is equivalent to a billion nuclear bombs going off in energy.
Isn't it the case that if you factor in the NAO and PDO phenomenon that explains a large part of the warming in the 20 years from 1977-1997 and the melting of the arctic in the last 20 or 30 years? I saw an article that said that at least 50% of the warming in the arctic can be explained by the NAO phenomenon and the rest by black carbon from non-CO2 pollution. Doesn't this automatically reduce the CO2 feedback component? Why should I believe the NAO and PDO will disappear and stop considering there is no evidence they are stopping? Because some theory of feedbacks not backed by anything more than a historical analysis using data that is quite suspect and models with unproven feedbacks is put forward as one plausible theory? I would be more likely to believe that the heating we've seen in the last 30 years is due to the same things that caused the heating in the early part of the century and in the preceeding centuries + NAO and PDO added?
Saturn, 99% of our atmosphere is almost completely transparent to light and thermal radiation. The only thing that matters, for greenhouse effects, is the small amounts of the gases that interact with radiation. That's CO2, H2O, CH4, N2O, O3, and a few other trace gases. These greenhouse gases are what makes the planet livable at all; and so changes to that small amount matter.
ReplyDeleteThe change from 0.028% to 0.058% can only be sensibly called a 0.03% change if the other 99.9% is comparable with the CO2. It isn't; so speaking of a 0.03% change is not sensible at all. It is a change of over 100%, and the effects of that are dramatic.
But do note that the effect on temperature is logarithmic. 100% change does not double the effect; but rather adds another 3 degrees or so. This is enough to take the planet far above anything that has been seen for many millions of years.
I ascribed 1.6 W/m^2 to CO2; not 0.6K. The corresponding temperature change is about 1.3K or so; and I'm not going to go again into all the issues associated with basic first order calculations. But note; this is a consequence of CO2 changes that have already taken place; NOT a prospect for the future.
You are being inconsistent when you speak of this not being cause for worry. We'd be fine if that was the only change... but it isn't. Greenhouse gases are continuing to rise, as you have noted. THAT'S the cause for concern, and more importantly, because it is in the future, it really is something where we can make a difference. IF humanity does nothing and continues accelerating fossil fuel use at the present rate, the CO2 level is not going to stop at 580ppm, which you quoted. But if we recognize the risks and moderate the pressure we place on the system by a combination of realistic measures, then we can most likely stop before reaching that level. Ideally, we're going to reign things in and keep levels below 500ppm (450ppm would be better, but unlikely).
You calculate a 0.14K for a possible 0.2% change in solar radiation, but your method is basically using Stephan-Boltzman approximations, which ignore feedbacks. Feedback works in much the same way for the Sun as for greenhouse warming, to amplify the effect.
The proper calculation is 240 W/m^2 solar insolation; scaled by 0.2% to give a forcing of about 0.5 W/m^2. Sensitivity of climate is about 0.8 K/(W/m^2), so the temperature change is actually about 0.4K or so. Furthermore, since the Sun is right at a maximum, changes in the future are more likely to be down than up. That would help offset greenhouse warming... but not all that much. The forcing from 100% increases in CO2 levels is about 3.7 W/m^2; roughly seven or eight times greater.
The oscillations you mention are not energy sources. They are oscillations; variations that come and go in complex cycles. They make it hard to calculate the sensitivity, or the response of climate to a forcing; but we still have a pretty good notion of the range of responses that are plausible or which make physical sense. Furthermore, the uncertainty involved goes both ways. The 3K temperature increase expected from a 100% increase in CO2 levels could be 2K or 4.5K (90% likelihood estimates). Rational risk analysis prepares for both, and pays particular attention to the worse case. We'd better hope it isn't the worst case; but in any case, we can and should take stock of what we have been doing to the atmosphere and try to manage it better.
The effect of your proposed increase of CO2 is massive; dwarfing anything solar variations are likely to do. The "billion atomic bombs" going off is true enough; but that is 160 million kilometers away, in the Sun. It is also a blip on the radar by comparison with the total solar radiation output, which is of the order of 5000 billion Hiroshima-sized atomic bombs going off every second, all the time. We only get a fraction of that at the Earth.
I do not think I am over playing the rottweiler analogy. Another phrase adapted from US political campaigns that has been used (and I don't mean to give offense, but I think it is amusing and very appropriately blunt): "It's the physics, stupid".
> 99% of our atmosphere is almost completely transparent to light and thermal radiation. The only thing that matters, for greenhouse effects, is the small amounts of the gases that interact with radiation. That's CO2, H2O, CH4, N2O, O3, and a few other trace gases.
ReplyDeleteH2O of course is huge both in terms of its content of the atmosphere and effect. Something like 90+% of the GH effect is because of this. This is why the "feedbacks" have to be considered because CO2 is a SMALL part of the overall GH effect. The IPCC took the position that all the other players are neutral and the only thing changing is CO2 and that increases H2O (unproven but they assume this connection which then gets them the 2 - 4 degrees they wanted in order to scare everyone).
This actually gets to the principal problem which is that whether or not CO2 is actually going to heat 0.6 or 1.2C is irrelevant. Nobody will get excited about that. Everything really rests on this unproven assumption that H2O will surge. This is the big problem.
H2O hasn't risen. In fact rainfall has risen. Rainfall has risen way beyond what the GCMs predicted. This also points to a problem with the models. They have failed in every way imaginable. Because H2O content hasn't increased we haven't seen the feedbacks expected. This has led the author of the IPCC AR4 feedback section to recant and now suggest that there is no connection.
What we have is a hysteria built upon unproven science being promulgated by a political group misusing science to push an agenda that is based on misusing science. You said "it's the physics, stupid." I'm just asking you and others to really stick to that. There is no physics which can be proved that shows a >0.6 or > 1.2C temperature change from a doubling of CO2. Everything that is used to show > than that amount is pure conjecture, philosophy, theory and unproven. All the data is pointing in the opposite direction that the feedbacks may actually be largely negative.
> But do note that the effect on temperature is logarithmic. 100% change does not double the effect; but rather adds another 3 degrees or so. This is enough to take the planet far above anything that has been seen for many millions of years.
Again, you state 3 degrees which you HAVE NOT Proven. I don't want to belabor but even if I take your physics you don't prove 3 degrees but 1.2. As to your assertion that this is greater temperature than the planet has seen in millions of years this is greatly disputed as well.
You can believe what you want but if you really believe the statement "it's the physics, stupid" then you wouldn't be making claims that are not proven.
For instance, while the MWP is in dispute as to how far an extent it was spread over. Some suggest just northern europe and greenland but there is evidence it was more widespread. It does strain credulity to imagine a "hot spot" in greenland of such a duration and extent that somehow lived without the rest of the world any warmer. Is there any such example of climate over centuries being hotter in one place but not others? If so, I have never heard of it, but even assuming that it was limited to northern europe and greenland the temperature CLEARLY was warmer than 3 degrees you pointed to and nothing bad happened at all. Vikings farmed, plants and animals existed fine. There is no evidence of mass extinctions, deaths or anything bad happening at all as a result of this massive warming.
> Greenhouse gases are continuing to rise, as you have noted. THAT'S the cause for concern,
i don't know if you noticed but so are walnut productions going up. When will it stop and when will the negative effects of walnut glut be mitigated. Don't we need to stop all walnut manufacture immediately?
Temperature has been going up since 1750 and the end of the last little ice age. There is no evidence there is any perfect temperature on earth. Every degree we've risen from that ice age has resulted in a better earth, a more productive planet and more life. There is no reason to believe that another degree or even 3 will be any different.
The planet is covered in snow and ice. If you've flown in a plane you will see that most of the earth is unlivable and unarable. A rising temperature so far (since 1750) has been always good. We wouldn't want to go back to 1675 and go into that ice age would we? Therefore who is to say what is the optimal temperature? It makes no sense to assume that any change from today is negative. That's absurd considering we've gone up a long way from 1750 and it has always been good. Even if the rise was a bad thing it is not clear what the right response is. Probably not burning our food supply!!!!
What we should have done 40 years ago is build massive numbers of nuclear power plants. Then we wouldnt be having this whole CO2 debate but since people "like you" or anyway people who promoted a scare about nuclear power forced us to stop building them they led us INTO THIS CO2 scenario. The same wackos that told us nuclear power was unsafe (wacko because nuclear power is demonstrably the safest form of energy ever created) are telling us we are going to die from 1 or 2 or 3 degrees warming when the evidence for that is just as specious.
I give you your 1 degree. Monckton doesn't for good reason. He says the troposphere is not responding as expected. Thousands of radiosonde measurements and satellite measurements over decades prove his point. It is a LAW OF PHYSICS that if the troposphere doesn't heat the force driving land temperatures (From CO2) cannot happen or is greatly mitigated. 2 papers have come out saying the heating is occuring in the troposphere. I give you those papers and assume that somehow someway 30 years of directly measuring the temperature of the troposphere is WRONG and these 2 recently published research papers are right. So, I am giving you rope that Monckton insists doesn't exist. Nonetheless even with the 1 degree it is scientifically IMPOSSIBLE to defend the idea that we triple that number to 3 degrees because of fantastical models and assumed physical interactions all unproven, all questionable, all proven to be inaccurate and inefficient and then to conclude the world must do something when it is unproven there is really any substantial negative effect from this rise even if it were 3 degrees.
As monckton points out in his summary. This entire scare over AGW is absurd on every level imaginable. Even if we grant you everything you want, give you 3 degrees which is unsupportable by real science and physics all of the reprecussions are still non-sensical. The earth is a cold place. There was a time when life flourished on the earth when the Hawaiian waters were at 98 degrees fahrenheit. The issue is that even if we grant you and the scaremongers your worst case scenario it still isn't at all clear if we should do anything about it and what to do about it if we should. It is highly unlikely that the solution will be to mitigate CO2 output because the consequences for humanity are much greater negative to doing that then either fixing the resulting problems from the heating or simply living with the problems whatever they might turn out to be.
> IF humanity does nothing and continues accelerating fossil fuel use at the present rate, the CO2 level is not going to stop at 580ppm, which you quoted.
I believe it is unlikely we will get to 580 simply for the physics and economics. Alternative fuel costs are declining at 7%/year. Oil and fossil fuel costs are increasing. It is only a matter of a few decades at most before they cross and there will be massive incentive to stop using fossil fuels. It is far more efficient for us to spend money on making alternative fuels more efficient waiting a decade or so for these technologies to mature and then go hog wild when the cost and efficiency will match fossil fuels. Then we will stop putting out so much of your "evil" CO2 which actually is a food supplement for plants. We may find the loss of CO2 in the atmosphere, resultant cooling and plant decrease will actually make reducing CO2 a bad thing but it will happen regardless and CO2 will never reach the 580ppm level and certainly not go much above it. So, the fear that it is all going to go out of control and we will be at 1000ppm or 2000ppm is absurd. That is impossible. Therefore, there is a limit to this that is going to be reached naturally whether you or I do anything to change public policy. It will just happen because of the economics.
Economics is a science too. It is called the science of scarcity. What capitalism does is allocate scarce resources most efficiently. By trying to divert the market we are by definition choosing a less efficient result and therefore mankind will suffer if we intervene in the natural market mechanism for dealing with our energy problems. We can help it along by making research that promotes new choices in the market but the adoption of those technologies should be driven by the market in order to benefit the most people. As far as the earth. It's doing fine. Temperatures are actually down for 10 years. Satellite measurements show plant life is 20% more than 40 years ago. Plants and animals which eat plants are doing great overall. All the fearmongering isn't helping. Stick to the science. What we know is that maybe we might get 1.2degrees but maybe not. We might end up colder at the end of the century after everything falls together. There are a lot of players and all these things work independently to a positive conclusion and thus we have where we are today which is with humanity doing a lot better than ever before and the planet actually doing okay, maybe even good depending on how you look at it.
Are there problems that need to be looked at? yes. We need more fish and the coral reefs worry me. We need to take better care of the ocean. We need to move away from fossil fuels. Everyone knows they aren't sustainable and are evil for the pollution they create (not just CO2). We need to deal with the persistent poverty and lack of democracy in the world. Lots of things to worry about but not CO2 based on any physics or science I have seen.
Monckton may be incorrect about reducing the AGW by a factor of 10 just as the IPCC may be wrong that it is 10 times worse than Monckton. I will guess it is somewhere between 0.3 and 3 degrees. I am guessing we will see close to 1 degree in 2100. This is simply not a problem that anyone needs to worry about. The other problems I mentioned are all infinitely more important. We are about to make the same mistake made in the 60s about nuclear power. CO2 isn't unsafe at the levels we produce it and we will stop producing it in time. Nuclear power wasn't unsafe and if we hadn't listened to these same scaremongers 40 years ago they wouldn't even have this scare to throw at us too. It's silly.
Thanks for all your other physics at the end I didn't respond to but I take as good work and good science.
Blogger comments are not a good place for a debate. Furthermore, sufficiently obdurate determination to hold a position in spite of anything is completely invincible in debate; you can never convince someone determined to be unconvinced. So that is not my objective.
ReplyDeleteThis is not a scientific debate anymore. It is science vs outright pseudoscience; and I say that while also recognizing that some people are honestly confused. If I can help a little bit with the major problem of education, I will; but I'm less interested in long debates. Persuading those determined to remain uneducated is futile.
If people want to sidestep the admittedly difficult job of learning enough about the details to have a meaningful personal opinion, then they should at least apply a bit of common sense to the choice of experts they use as a guide. Contrasting Monckton with the IPCC as if they represent comparable alternatives is ludicrous.
A reasonable first step is to bypass individuals directly involved in defending their own research, and look to professional bodies representing a whole field of science; or even better – to the national academies of science around the world. They are well placed to evaluate the state of scientific debate generally. Pretty much every national academy of sciences around the world has made a strong statement endorsing the basic facts of this faux-debate on warming. The world is warming, and the major cause of this is human activity through a greatly enhanced greenhouse effect. You can take it to the bank. See, for example, this Joint science academies' statement of the national academies of science for Brazil, Canada, China, France, Germany, India, Italy, Japan, Mexico, Russia, South Africa, UK and USA. Similar statements can be found from the European Science Foundation, the Network of African Science Academies, etc, etc. A huge list of such statements from professional scientific bodies is collected at Wikipedia: Scientific opinion on climate change.
If you take the trouble to learn a bit about the physics it becomes even clearer. There's no longer any rational basis at all for failing to recognize the crucial importance of greenhouse gases to climate effects. They stand out a mile as the major cause at work in the present; it this absolutely is just the physics. The harder question of how much warming might result from doubled CO2 levels is open; and there's lot of different estimates for that. But it is very unlikely to be less than 1.5C, and unlikely to be less than 2C. The best estimate is 3, and it is unlikely to be more than 4.5C. Rational response takes all these possibilities into account; foolhardy ignorance makes up its own guesses on no good basis.
Saturn, I appreciate your generous closing comments, but I am much less impressed with some of your other remarks. I am glad some of this has been useful, but of lot of it you don't even seem to read; you've mixed up my numbers badly, and your own numbers appear to be sheer wild imagination. My forlorn hope is that you'll continue to look into this for yourself in the coming months. If you do come to change your mind, it will be best from your own conviction, and that will take a bit of time if it occurs at all. Here are just three comments on some points that have a bit connection to the main blog post.
(1) H2O drops in and out of the atmosphere very quickly indeed. That's NOT an assumption; it's just a basic fact of physics. If you try to add or remove H2O directly, natural cycles bring it all back to equilibrium in a matter of days or weeks. The levels of H2O depend on other factors, especially temperature, and hence H2O is an engine of climate change; not a driver. The direct contribution of CO2 is between 9% and 26% of the greenhouse effect; while water vapour including clouds is between 66% and 85%. The range of numbers is not because of uncertainty; but because combined effects are not a simple linear sum. See Water vapour: feedback or forcing?. This percentage contribution is only part of the story. CO2 is a long lived part of the atmosphere, and therefore adding, or removing, CO2 does bring about a persistent temperature change, where adding H2O directly does not. The effect of CO2 on temperature is amplified by increased moisture levels. That's why H2O is primarily a feedback; not a forcing. Refusing to recognize this is refusing to recognize some simple facts about how weather works.
(2) Saturn asserts H2O hasn't risen. That's simply false. Mean H2O levels in the atmosphere have risen and this is measured. Because humidity varies so much with time and location, the measurement is not all that precise; but the trend is 1.40% (+/- 0.78) increase in total column water vapour per decade. There's a lot of work on this that tells the same general story; I'm giving the numbers from a significant recent report by Soden (2005).
(3) Saturn says: "You said "it's the physics, stupid." I'm just asking you and others to really stick to that. There is no physics which can be proved that shows a >0.6 or > 1.2C temperature change from a doubling of CO2. Everything that is used to show > than that amount is pure conjecture, philosophy, theory and unproven. All the data is pointing in the opposite direction that the feedbacks may actually be largely negative."
There's not much to say to this other than: you are way off with the fairies now.
It absolutely is just the physics, and you also need to learn what "proof" means in science. You're misquoting my numbers. It's actually somewhere from 1.5C to 4.5C for a doubling of CO2; you may be mixed up with the 37% or so increase from pre-industrial to now, which would be somewhere from 0.7C to 2C increase. That's not "proven" like a maths theorem, but it is a well supported inference with a high level of confidence, based on simple calculation of the forcing, and constraints on sensitivity both from empirical and theoretical considerations.
There is no data pointing in the opposite direction, and the suggestion of negative feedbacks is lunacy. The most recent lunatic who suggested that was Roy Spencer, in a testimony to the US senate. Spencer actually is a climatologist, who has pretty much exploded his credibility in recent years, for this and other reasons. His "argument" for negative feedback is not based on conjecture or philosophy, but outright undergraduate level error. He uses frequency analysis over a short time span from satellites to calculate a sensitivity, and the time scale used pretty much assures that he's mostly measuring the immediate baseline response, not the feedbacks at all; quite apart from the large uncertainties. His "estimate" of feedback is unphysical and given without uncertainty limits, which would be massive. I am genuinely angry about this. Spencer has prostituted his integrity with dumping this nonsense on the senate. (Ref: here; I'm hoping there will be more analysis of this point taken up online.)
Duae,
ReplyDeleteThanks for entertaining my questions. You are a true gentleman for taking the time and effort to educate your blog listeners and me.
> There is no data pointing in the opposite direction,
I think that pretty much says it. We had a thirty year cooling, a 20 year warming and now 10 years down. The troposphere data is not solid or defensible, the ocean is getting cooler and on and on and you say the data is not going in the opposite direction. Don't you realize the debate is not shutting down as it should if the arguments were rock solid and the data was truly consistent. If we were experiencing the type of heat the models predicted nobody (including me) would be debating the feedbacks. I might still be debating the negative effects of the warming but I would be on your side totally as to the physics and the science.
It's the opposite. Now the debate is over "whiplash journalism" and APS publishing contrary theories and more and more people are becoming disillusioned. Recent polls show that even in Europe which was 98% convinced global warming was bad and we need to do something about it is now more like 50/50 in britain. All the climate bills in the european and american governments are being buried. The politicians who support the AGW hypothesis were screaming about how nobody was listening a few months ago and now those same politicians won't even talk about the issue. In america Nancy Pelosi has gone into hiding after she said "She's trying to save the planet."
The consensus of scientists is crumbling. 31,000 scientists signed a statement saying they question the idea of severe AGW several months ago. Papers are being published showing that temperatures won't go up for 5 or 10 more years and then will magically catch up. Other papers are questioning all the feedback assumptions in the IPCC AR4, other papers showing the models are useless and still other papers showing ocean temperatures declining. The arctic has stopped melting, there will be no ice free north pole this summer as predicted, instead the melting is about the same as the average of the last 30 years. Alaska is having the coldest winter in 120+ years of recording. Antarctica is continuing its 50 year defiance of GCMs and staying cold as outer space practically.
Yet you say there is no problem. This is where I'm having the problem Daue. Scientists are supposed to be skepitcal not clinging to a theory like their life depended on it and quoting political documents that have no science in them as if they were religious texts we could all learn from. The APS statement of its position on global warming reads like AGW-Goebels came back from the dead and had it transcribed from Mein AGW Kampf or something. These kind of statements have no place in real science. Science is becoming politicized. It's obvious.
I very much like your statement "it's the physics, stupid." I studied 3 years of physics at MIT including quantum mechanics and waves and thermo. I studied computer science and mathematics. I know quite a lot about proofs having done many many many in school. I have studied linear algebra and several semesters of real analysis and of course calculus so I get the math and the science and it just doesn't make sense to me and coming from MIT with all that background I don't take mindless drivel like the APS "statement of position" or other politicized statements very well. I need to see the physics myself and the fact is that my analysis is that the AGW crowd has NOT proven its case. I believe the particularly weak part of the argument is the computer models and feedbacks. I think you did a good job with other parts and explaining where Moncktons argument may fall apart.
Of course the other weak part is that the data is fueling an immense skepticism. I don't accept the idea that it is "normal variability." I've explained why earlier but I believe the honest scientific statement is that the data doesn't support the theory yet either. You and Hansen and others are saying: Wait. It will support it. Just give us 5 or 10 more years. However, another team has just told us there won't be any warming for 5 more years at least and I beleive them because to me I don't see where all the heat went and the ocean is cooler. That seems to be a big problem. The ocean has 300 times the heat capacity of the atmosphere. Any cooling of the ocean puts a huge block for me on how the world is going to get warmer.
The sheer fact that most of the southern hemisphere is in a severe cooling trend that has been going on for some time is damning and the fact that the northern hemisphere now seems to be going in the same direction even though CO2 has been going up faster than anyone imagined is disconcerting to say the least. Where can all this heat be going? Obviously something is wrong.
What I think people need is precisely what the APS journal set out to do. We need a debate with real science so we get a feeling of what the problems are. We don't have a rock solid theory. The first step is admitting there is a problem. The fact the APS couldn't produce a physics or other paper to defend the models or even the sensitivity to CO2 but left us with the only thing they really could prove: the watts that should be generated from a certain amount of CO2. Great but that is a far distance from what is required to convince people there is a problem that is proved to exist.
I am quite convinced that CO2 affects the environment. So does hundreds of other things. The question of the day is will that effect be worth doing something about and that means scientists need to prove that we are going to get 2 or 3 degrees. I still believe that proof has not been forthcoming and is not obvious.
I also of course as I explained in the last entry explained that even if temperatures go up there is hardly anything to worry about but that debate is for another day assuming there is any significant temperature rise. Lastly of course assuming we can prove that the rise will happen and proving that the consequences will be net negative (also not obvious) then we have to set out to prove what the result from various strategies would be. As people have pointed out we are jumping the gun. We are putting the cart before the horse and doing things like burning our food supply before we know if there is even a problem.
Since the last part is more debate as you say you don't have to respond and we can leave our differences as they are now or you can try to explain why I should have confidence temperatures should normalize and come into compliance soon. That's something I don't get. This faith that temperatures will come back is boggling. The heat seems to have disappeared from the system. I don't see how we get to 2 or 3 degrees from here. It seems incredibly improbable and require an amazing run of temperature increases that are just not plausible considering we are going into a negative phase of the PDO and NAO.
If we reset the models to initial conditions of today and we soften the feedbacks to account for the lacking H2O in the atmosphere there is no way to get to 2 degrees by 2100. Therefore it isn't a problem except for all the climate people who kept telling us to blow 15 trillion dollars to fix a problem that doesn't exist or who made money fanning flames of hysteria to get grant money.
DQ voices his opinion of Saturn´s competence thus:
ReplyDelete“I will also be very dismissive of Saturn's claims.”
and he goes on to intersperse his arguments from physics with an extraordinary concatenation of ad hominem insults, viz:
“The heart of the problem of what word to use for the AGW-skeptics is that their arguments are so dreadfully bad.”
“You need to wake up to yourself, Saturn”
"It's the physics, stupid".
Saturn might have said “You need to wake up to yourself, DQ” and "It's the facts, stupid". But he didn´t.
His avoidance of the easy ad hominem is admirable: his concerned arguments are restrained and altogether convincing.
DQ´s cosy little “Me and Gavin, yeah, that's the ticket.” is utterly nauseating, is it not?
“Respect the facts!” Chris, and you might justify the label
"physicist", rather than the train-spotting, computer-modelling nerd you appear to be. (Er…, no ad hominem intended).
Ad hominem is not the same as criticism. An ad hominem argument is one that uses comments on persons as the basis for argument.
ReplyDeleteSaturn's comments are welcome. He provides a strong focus on substance, and accepts with good grace the focus on substance which I give in return, without getting upset that I think he is completely wrong. Likewise, I don't mind that he thinks I am completely wrong.
I am preparing a response to saturn, but without being in any rush. Both saturn's comments and mine have a strong focus on substance, and we both have critical remarks about each other. Neither of us has attempted to argue from the person as a premise, which would be ad hominem. Being critical is not ad hominem.
Anonymous' comment above, on the other hand, is classic ad hominem. There is no use of substance, and the basis of argument is all on persons. This is destructive and unwelcome.
Gotta say saturn, it is nice that you don't take any offense. You are, however, completely wrong on the specifics in nearly every case. So here we go again, with no personal attack intended as usual. I'm responding to this comment.
ReplyDelete(1) Saturn says: "We had a thirty year cooling, a 20 year warming and now 10 years down."
These widely repeated claims about the last 10 years are simply false. Get the data for yourself, put it in a spreadsheet, and calculate the regression for the last ten years. It will show a warming trend. Use the HadCRUT3 data, because it shows less warming over the last decade than NASA-GISS datasets. (HadCRUT3 omits the poorly measured Arctic Ocean from the average calculation, while GISS extrapolates values from highest latitude measurements.) The link also shows some plots, which reveal lots of natural variation; and with smoothing it shows an upward trend since around 1950, which is especially strong from 1975 onwards.
Using just the last 10 years of monthly data, you get about +0.05 C/decade warming. If you use the annual timeseries, then you get about +0.07.
If you take any other ten year window up to any other month in the last decade… you still get a positive warming slope. Start right from the peak of the 1998 high and measure ten years forward. It still shows warming.
The most recent ten year window with a negative slope was 1987 through to the end of 1996, or into early 1997. This is right in the middle of what saturn rightly identifies as a period of warming. It's just perfectly natural variation.
To see the effect of normal year to year variation, look at the range of slopes over every ten year window back to about 1970. The average is over 0.18 C/decade; but the standard deviation on ten year slopes is 0.11 C/decade. Thus the slope for the most recent ten years is about 1.25σ below the mean, well within normal variation. You would need cooling over a fifteen year window to be 3σ below average.
(2) Saturn goes on to say: "The troposphere data is not solid or defensible, the ocean is getting cooler and on and on and you say the data is not going in the opposite direction. Don't you realize the debate is not shutting down as it should if the arguments were rock solid and the data was truly consistent. If we were experiencing the type of heat the models predicted nobody (including me) would be debating the feedbacks. I might still be debating the negative effects of the warming but I would be on your side totally as to the physics and the science."
Nonsense. Available evidence robustly shows an increase in tropospheric moisture. There's a lot of ongoing work to nail down the details, because moisture content shows large natural variation across seasons and location. But the overall trend of increasing moisture shows up strongly. I cited and linked a recent paper above (Soden 2005); saturn ignored it. More work on this includes Santer et al (2007), Trenberth at al (2005), and IPCC 4AR sec 3.4.2.
I don't know why specifically saturn thinks different. He gives no data or argument; only an assertion. But there is a plenty of data on this, and the conclusion of increasing moisture is robust.
Similarly… the ocean is not getting cooler. The situation here is more complex. There were some legitimate papers arguing for cooling of the ocean a couple of years ago. Since then, the authors have identified and measured systematic errors, and withdrawn the claim of cooling. (Willis et al, 2007).
There are still outstanding problems in reconciling all the different measurements, outside confidence limits, and so there are still unresolved systematic errors somewhere, and this is being actively investigated. The issue concerns short term variations. Everyone working on this still recognizes an ongoing warming trend in the ocean. (Ref: NASA JPL news release; and a recent statement by Josh Willis putting his work in context.)
(3) Saturn says: "31,000 scientists signed a statement saying they question the idea of severe AGW several months ago".
Argument from authority backfires badly.
The petition is not limited to "scientists"; anyone with a science degree can sign up, and even that is not checked. It was not "several months ago"… this petition has been collecting signatures for nearly ten years now. There are lots of people with science degrees sucked in by the nonsense, but the arguments used (as we see also right here) don't even use minimal levels of checking. The material associated with this petition is spectacularly bad, and the petition statement on the relative merits of evidence is more or less insane. You get the same kinds of informal uncontrolled petition in lots of fields of pseudoscience.
For people who like argument by authority, my response is in the comment on 5 August 2008 08:33. Look at the formal statements of national academies of science, and professional bodies that have national representation for a whole field of science. There are hundreds of formal statements by such bodies noting the reality and seriousness of AGW; and none denying it.
Strong statements on all sides go beyond disagreement on AGW, and claim that the other side of the debate is not merely wrong, but actively incompetent – or worse. So it's not just about AGW. It's about science education and practice generally. So who represents the pseudoscience? The NAS? or the 31,000+ signers of the petition? Here's a free clue: it's not the NAS.
I find it surreal that anyone would think the Oregon petition makes a better argument from authority that the formal statements of the NAS, AAAS, Royal Society, NSF, national and multinational science academies all over the world, and hundreds of national organizations representing a particular scientific field. But so be it. As for me and my house, we will continue to rely on examination of evidence and argument.
(4) "The arctic has stopped melting"
I'm guessing this is not quite what saturn meant; but in any case: the Arctic is still melting; and will continue to melt through to the September minimum, which at this point seems likely to be one of the biggest melts on record; probably something like the third or fourth lowest ever. We'll see soon enough. (Arctic Sea Ice News, Aug 1, 2008) Everyone working in this area expects the trend towards less and less Arctic ice to continue into the foreseeable future.
(5)"there will be no ice free north pole this summer as predicted"
That was never a prediction; it was described as a 50% possibility. Furthermore, although symbolic, whether the North Pole itself becomes part of the melt this year is not actually dependent on temperatures, but on currents. The Pole seems likely to remain covered in ice this year. (More detail: North Pole Notes)
(6)"the melting is about the same as the average of the last 30 years"
Nonsense again. Where do you get this stuff? As of July 31, the sea-ice extent was 7.71 million sq km; well below the 1979-2000 average of 8.88. Global warming affects the totals more than the rate of decline, since both maximum and minimum ice extents are in a general decline. (Arctic Sea Ice News, Aug 1, 2008, again.)
----
There's more, but the above are the simplest outright errors in saturn's comment. I don't doubt that saturn could fix these up and carry on pretty much unchanged; because there is an endless supply of such errors being presented with bland confidence by those denying the science behind AGW. If you don't check things out, you [i]will[/i] end up being deceived. I suspect saturn is the victim, not the source, of these errors.
Here's a more general point.
This mismatch between scientific and public debate on this is not because the science is settled. There is lots of active research and dispute going on to sort out details and points on which we are uncertain.
We know about uncertainties and inaccuracies. None of them do any damage to the conclusion that the Earth is warming up significantly in recent decades, or refute the notion that this is a trend that is highly likely to continue, along with the natural variations seen observations and predicted by theory.
We know about lots of different factors that impact on climate change. The point about "it's the physics" is that you can quantify the greenhouse forcing quite accurately… and nothing else even comes close as a comparable contribution to warming over recent decades. The other effects are important… but they are smaller than the greenhouse effect.
We know about trends and natural variation. It's a pretty basic calculation that you need something like cooling over a 15 year window to be 3σ outside the normal variation seen in the warming trend since 1970; and over an 18 year window to be 4σ. This might be a good topic for a blog post sometime. In the meantime, people rabbiting on about how cooling has stopped are really only advertising their inability with trends and timeseries.
We don't know the climate sensitivity for forcings, except within generous uncertainty bounds. Claims for negative feedback are way outside those bounds, and are based on fundamental errors by a tiny handle of individuals, and then get picked up – it must be said – by credulous simpletons who have no idea how to derive a sensitivity estimate. The evidence simply does not support this in the slightest.
A maverick in science can explore ideas that don't fit what is conventionally considered known. This is an important part of how science works. The crank or pseudoscientist claims to have already proven that everyone else is wrong, on the basis of arguments riddled with errors, and loudly proclaims that it is only bias that prevents their insight from being accepted. The denial of AGW is nearly all pseudoscience.
DQ, I appreciate your patience, and the even handed way you are addressing saturn. I do think however, that he is jumping all over with his comments, which simply makes the discussion more difficult, and less rewarding than focusing on one area at a time.
ReplyDeleteI do have what might be a stupid question. Monckton has used his perceived lack of tropical mid-troposphere heating as a reason to slash the sensitivity by more than one third. Well, he actually slashed the CO2 forcing by one third, but basically he wants to simply throw a fudge factor in reduce sensitivity, and he doesn't seem to care where he puts it in, based on his recent rebuttals. His reliance on tropical mid-troposphere data to change the entire global physical model seems mis-placed. And if I understood you correctly, the stratosphere cooling is an extremely strong fingerprint of radiative forcing from increased CO2 and manmade GHGs.
Since Monckton is mis-using data on the lower than expected tropical mid-troposphere heating, it might be helpful to focus on what other causes could possibly affect this. So to my question:
When you described the connection between the CO2 forcing and the water vapor feedback, you seemed to indicate that the CO2 is absorbing and re-radiating energy throughout the troposphere, and by causing some warming there, increases the amount of water vapor present, and hence getting a positive feedback leading to more warming than would be expected from the CO2 increase by itself (increased sensitivity?). But is it possible that some other factors could limit the increase in water vapor levels? Perhaps there are circulations of the troposphere in the tropics, that mixes and cools the mid-troposphere enough, such that the water vapor positive feedback isn't as strong as the models might suggest? How is the troposphere in the tropics affected by the higher rotational speed of the earth, compared to the slower rotational speed at the higher latitudes? Are there other factors that you can think of that would limit the penetration of water vapor to higher altitudes, and thus give us a muted warming in the mid-troposphere? Is it possible that the gases in the mid-troposphere are not as saturated with water vapor, as we might expect, due to limitations in mass transfer rates etc.? What about periodic drops in temperature, reducing or condensing water, then re-warming to a less saturated water vapor state?
I don't have an agenda here... I am just brainstorming, and in that process, a lot of ideas come out that are "stupid" and can be dismissed easily. I just was wondering, instead of relying on simply questioning the data collected, whether the models themselves need modifications to account for different behavior of the mid-troposphere in the tropics.
Hi zinfan94,
ReplyDeleteThis may sound like a cop-out; but my speculations on the different factors that impact water vapour are not worth much.
Speculations are a dime a dozen. You're better to study the matter for yourself. That way you learn about the various speculations and proposals already considered by people who study this for a living; and you also end up in a position where your own speculations start to be more meaningful. I'm not there yet, so I can't help much on causes of humidity variation.
The reason AGW lost the debate for me was the conduct of the various pro-AGW blogs, and the conduct of the Climate Science community.
ReplyDeleteI started out like most people just accepting the theory. It seemed to make sense, from the point of view of physics, and the Hockey Stick data seemed irrefutable support for the argument that the recent present was decisively different. I became interested, and started to read Real Climate.
My first unease was with the tone of dismissive abuse of any critical voices. It raised the hair on the back of the neck a little. This, one thought, is not the way settled science is defended. It was because of this that I started to read more widely. Rabett, Stoat, Tamino, Deltoid and others. The characteristic venomous tone was more marked. One had encountered it before, in the Soviet era from Party hacks. Increasingly suspicious, but lacking any real factual or scientific basis for this suspicion, I turned to the critical sites, and focussed on the Hockey Stick as a point of entry.
The first striking scientific issue was Mann's refusal to reveal his raw data. He was obliged to do this finally, but has still not revealed, even to Congressional Committee, his algorithm. I found the Wegman report with its endorsement of the M&M critique very convincing. From CO2 Science I became convinced that there's a mass of evidence that MWP both real and was global.
I started to discover two more things. First, a general pattern of the refusal to reveal data which would make results reproducible. This characterized the University of East Anglia group. We had the extraordinary episode where only proceedings under the Freedom of Information Act could compel the release of the identities of 80 Chinese surface stations. What conceivable legitimate reason could there be for that? Why was the Tornetrask data so hard to come by? But even outside East Anglian, how could it be, that Dr Thompson's data was in good enough shape to allow him to do adequate quality control for his published studies, but yet require totally excessive and impossible amounts of work to be got into publishable form? It made no sense. I concluded that nothing published by the Hockey Stick group was to be trusted.
In the face of the statistical and methodological demolition of the HS, the response of the AGW community was even more puzzling. It was defence at all costs. The continuing saga of the Hockey Stick has continued the pattern. We now have obtained most of the missing data. This has permitted full analysis, and we can see both that the statistical methodology was indefensible, and that the results are highly sensitive to the selection of data series.
I concluded that we have to throw it all out, and go back to the historical record as previously understood, and that the Roman Warm period and MWP were probably at least as warm as today, and that the LIA really did happen. This in turn leads one to the view that natural climate variability is far greater than AGW proponents have admitted, and so makes one sceptical about the unique and dangerous nature of modern warming.
At about this time the surface stations project began to throw up data, not only about the state of the stations, but about the way we pass from raw data to the climate record. It was not just that the stations seem sited so as to give a warm bias to the record. It was that the basis for the continual adjustments of the previous temperature record were incomprehensible. What on earth are we doing raising and lowering the recorded temperatures in some obscure town in Texas in the early years of the 20th century? This also makes no sense.
But at least in the GISS material one could get to the algorithm, however mad. In the case of Hadcru, the algorithm is kept secret. This is truly crazy.
We next came to the issue of the statistical validity of the IPCC forecasts. Lucia has patiently worked her way through the statistics, and shown that they are falsified at the magnitudes given. It does not mean there is no warming, but it does mean that, so far, the IPCC forecasts of 0.2 per decade are clearly falsified. It just is not warming as much as people had thought it would.
And so finally we come to sensitivity, surely the key issue. It was a surprise to me to discover (from Monckton) how the IPCC estimate of sensitivity had changed. Over the years, the direct effects of CO2 have been reduced, and the feedback effects increased. In conjunction with the observations above about natural variability, I became highly sceptical that feedbacks could possibly be of the size asserted. If so, previous natural variations would surely have invoked much larger swings. And it seemed impossible to reconcile the succession of coolings we know about from recorded history with the existence of such large sensitivities.
I concluded that we did not know why it had warmed in the past, nor why it had cooled. This affects your view of the present. The warming is happening, but is lower than forecast, and doesn't seem particularly alarming, or likely to continue indefinitely.
Meanwhile, I read Pielke. Now what emerges from Pielke is not that it is not warming. Nor does one conclude that CO2 does not matter. But one does see that other factors, like land use changes, are probably far more important.
And Pielke has also focussed attention on ocean heat content. And this too does not seem to be acting as it should if AGW were correct and catastrophic warming were round the corner.
To an outside observer, because I am not a climate scientist, this is a stock I would not invest in. There are too many things that don't make sense, and too many indicators that are not pointing in the right direction. It has all the marks of one of the great mass scientific delusions of the past - eugenics for instance.
Like Saturn, I notice around me in conversations a general mutinous scepticism about it. People just are not buying. We will see. Maybe the wisdom of crowds in this case will be wrong. Maybe this will have all the marks of being a bad one, but fly anyway.
But I doubt it.
Duae,
ReplyDeleteYour points are cogent and fairly precise.
I still have a problem as you can imagine.
While you and others claim the current data is within the normal variability the problem for me is that it isn't confirmatory. Yes, if you make the error bars big enough then of course any data fits within the error bars but that doesn't mean we've proved einstein is right. We can say that nothing disproves the standard model's postulation that the Higgs particle exists. The fact we haven't seen the Higgs particle is mildly good in that it didn't happen at an energy level too low for current theory but the lack of the Higgs particle also leaves a severe doubt in people's mind as to if we will find it or not. Now particle physics has a huge amount of supporting data for the standard model. We've been studying this for decades and yet people are willing to accept the fact that the non-existence of the Higgs particle will be a massive blow. Physicists talk about it all the time and nobody is going to be crying if it isn't found.
Yet, what is damning about "your" science is how you insist beyond all reasonable argumentation that there is no doubt this high sensitivity exists. All I'm doing is saying I no longer believe in high sensitivity. I say this because the models are stupid. Nobody could possibly believe the models actually predict anything and that is before all these new papers came out. It's patently obvious and even the modelers would never argue they are predictions for 2100. Your large error bars on temperatures more or less prove that the error bars on the eventual temperature in 2100 is quite large. We have no idea if it will be 2 or 4 degrees sensitivity or if temperatures will be down in 2100 in SPITE of high sensitivity to CO2. Other factors could be at play. The reason I say that is that the current "lull" (down for 9 years ... flat for 10) is unexplained. If someone could explain why the temperature is flattening like we did in the 90s with the volcanoes when we had some short period declines that would be very helpful. Maybe China is pumping out so much pollution or India that they are depressing temperatures like happened in the 1945-1975 time period. It's important to know that becuase the current data is putting doubt.
I am happy to believe in global warming at high sensitivity if it is true. I just don't believe it anymore. But that is almost beside the point.
I think what disturbs me the most on realclimate and here which are supposed to be more scientific and "truth" is the lack of willingness to acknowledge that sensitivity MIGHT be lower than 2 degrees or to acknowledge how difficult it might be to get to 2 or 3 degrees by 2100 and how the unprecedented temperature rises would be difficult to understand in the context of the PDO, NAO and natural variability that takes decades of "falling" temperatures. We only got 0.6 or 0.7 degree in the 20th century with 2 periods of very rapid temperature rises. In order to get 3 to 6 times the temperature increase of the 20th century we are either going to need some huge temperature jumps or some very consistent year over year increases. We are sitting here in the very first decade since the models came out with a 0.05 slope. This slope will result in LESS temperature rise than in the 20th century and this has been going on for 10 years. More worrisome is that temperatures are sinking so fast in just the last year dropping massively. Heat seems to have escaped the system. We can't say the heat escaped into the oceans only to come out maybe in 2 or 3 years because the oceans are COOLER. Amazing. This german team says we may have another 5 or 10 years of cool weather. If we do and this seems likely if not proven then where is high sensitivity Climate change theory going to be? They say it will all catch up but can you see why this is not the conservative "sure" "scientific" position to take? To bet on a massive unprecedented rise in temperatures at this point seems more like religion to me. The models don't provide any evidence to me. They are wrong. Every study shows they can't predict jack.
I think you are missing the big picture. Heat is missing. The explanations are unsatisfactory. How could the oceans be getting cooler? How could the land temperatures without volcanoes be getting cooler? How come the troposphere can't reveal its temperature to balloons? Is there something different about measuring temperatures in the troposphere compared to here on the land? How can temperatures sustainably go higher and higher without heat in the ocean or land or troposphere accumulating?
The problem is not simply that the data is barely withing the acceptable "natural variability" of the theory but that so much else is completely unconvincing and unexplained. Compounding that is the near religious zeal and derogatory way and political way these "scientists" are dealing with the issue. They keep wanting to suppresss debate, lambasting those who aren't believers as unscientific and stupid. I am an MIT grad with 4 years of rigorous science training and mathematics. I am not some stupid guy who doesn't understand simple math that is involved here. I have enough ego to not believe I'm stupid or to take political treateses like the APS "statement of position" as useful documents. They frighten me frankly. I've never seem a "physics" statement of position on einstein. It's absurd. Why would we need such a thing? It's is wrong.
So there is much wrong about this. The way the science is being debated. The lack of skepticism. The politicization. The fact that there is real reason to doubt 2-4 degree sensitivity. The lack of willingness to accept the theory isn't proven. It will take 50 years of sustained data collection for such a theory to even approach proof.
Let's get back a little to your specific points. I accept most of your data on ice extent, etc... I've been looking at charts at the official sites and they show a trend for ice in the arctic that is exactly on the same slope as the 30 year average. However, as you point out the ice is actually building from last year not exceeding last years decline or going to ice free as some predicted would be a 50/50 chance. That to me was political as there seemed to be no basis for this other than to create a news story. The real story was that ice extent was far GREATER than last year not less but that story wasn't reported.
" But there is a plenty of data on this, and the conclusion of increasing moisture is robust.
Moisture is robust absolutely. I never said that. What I guess I understand is that even though there is more H2O it is raining so the moisture is not staying in the atmosphere to increase heat. I guess people expected cloud cover to increase or something. This seems to be where the problem resides as the feedback calculations in the models assumed we would get this robust positive feedback with clouds and moisture in the atmosphere creating additional greenhouse effects. That has not materialized which is why the author of the IPCC feedbacks section is now recanted and said that there may be no relationship between clouds and moisture and heat or the relationship may be reverse meaning that the clouds drive temperature not the other way around which means that this component of feedback can be removed as a positive feedback and simply become a normal variability parameter.
I believe the biggest problem for the "high sensitivity" is the fact that 2/3rds of the high sensitivity is based on feedbacks in computer models that are completely unproven.
I insist that if you want to call yourself a scientist and not a political hack you have to acknowledge that computer models with complicated physics, massive assumptions about the interactions of many complex chaotic components cannot possibly be proven by the very little work done so far and that frankly the results from comparing models to the real world have been dissapointing. If you said that I would start to believe you were a scientist more and less of a politically motivated person.
This is all I'm trying to say. I'm not trying to "prove" the high sensitivity case is wrong. I don't know if we have proof either way. I would say there are reasons for severe doubts there will be high sensitivity. I expect any scientist to be able to admit this. It is impossible that any true scientist actually "believes" in these models yet. They are too new and there is so little to back them up and there are many reasons to doubt there legitimacy on purely abstract basis. So, that's all I'm asking is that the people speaking about this "theory" express the same skepticism and willingness to consider alternate theories as I see in physics or any other branch of true science.
When I see people issuing "statement of positions" as the APS did and so many other politicized organizations have it degrades science. We have no "statement of position on algebra" or something. We have no "statement of position" on the age of the universe. These imply somebody is trying to "force" us to believe not unlike when you go to church and they make you recite "god is great" over and over. It's scary, daue to see science reduced to "I believe in high senstivity global warming" " i believe it is proved" and repeat over and over until everyone agrees. That's why I have liked your comments so far because at least there is an attempt to defend the science but I think you could still be a lot more skeptical and willing to consider where the weaknesses in the science are.
We are not idiots. We know there must be weaknesses. There are weaknesses in the standard model of particles in physics. This is a theory under intense intense intense scrutiny for nearly 100 years. We have had billions and billions spent trying to confirm every detail and we still don't know if the whole thing will fall on its face in the next year if we don't find the Higgs.
Duae,
ReplyDeleteOne last point.
Another very disturbing thing to me that has given me grave doubts about high sensitivity is the fact of the timing of this temperature lull.
As I've said before models are a dime a dozen and getting some which match past data is no hard feat. In fact several articles have pointed out that if you took a flat line it would be almost as good as all the models in "accuracy" so I start with the presumption which I think in science is very important that our theory has zero validity until presented with facts that confirm it. The models were issued in 2001. Since that was the starting point the fact that they immediately failed to predict this lull or that we got it is very concerning. Maybe it's just random bad luck but from a betting mans perspective it casts tremendous doubt. It obviously reduces drastically the probability of correctness if the first 10 numbers to pop out of your random number generator happen to be less than 10 that you have a random number generator that creates randomly numbers between 1 and 100. What are the chances that the first 10 numbers out of the random number generator are all lower than 10 when it is supposed to be generating numbers up to 100 randomly? Yes, it's possible and there are runs of numbers in any 10 range that can go for a long string of times but it puts into doubt that it truly is a random number generator when the first 10 happen to be just by chance to be clumped together like this.
Yes, the data fits within the error bars but the timing of the data and its extent is incredibly worrisome. It would obviously have been much better if temperatures had gone up much faster in the first 10 years since the models were issued. The probability of them being correct seems greatly diminished because no data supports them according to my way of thinking. Again, this is because I don't consider regression tests convincing.
Frankly, for me I have no reason to believe in high sensitivity because I don't accept past data as convincing since there are millions of ways to explain past data or to model it and many physics and climate variables and processes we don't understand. It is not likely to me the models are correct because of their newness and because of our lack of understanding of the climate generally and because of many other reasons, one as simple as "what proof" do we have that the models are even coded correctly? What processes were used in the validatiion of the code? It wasn't until recently that the code was even released on some of the models.
I also want to emphasize again that as the temperature data continues to be moderate it makes the probability of 2 or 3 degrees by 2100 less and less likely even if the theory is correct. It seems likely there will be other lulls since we've already had this one. We have the PDO and NAO documented pretty well now. They seem consistent with the current data therefore making them seem like real phenomenon much more than high sensitivity global warming. They also explain things like the fact the arctic has heated up but NOT the antarctic. It explains why this year has turned out cooler better than AGW models.
These things place doubts in people's minds. Maybe you still "believe" in high sensitivity but you can at least understand why others may have doubts and these doubts aren't evidence of complete mental deficiency.
If we say in 2001 that the probability of 2 degrees in 2100 was 90% according to the IPCC what is the chance of 2 degrees NOW? I believe it is LOWER. Much lower. The sheer fact is you've lost 10 years. Frankly, temperatures are down absolutely almost 1/2 degree since 2000. We now understand the PDO and NAO will probably give us some pausing. We have doubts about cloud and temperature feedback. All of this suggests that sustained large continuous temperature increases seem less likely making 2-3 degrees by 2100 less and less likely. It seems to me a prudent thing would be to say it is likely our range for a doubling of CO2 or 2100 is more like 1.2 degrees or twice what we did in the 20th century. That to me seems possible if temperatures increased substantially in the next decade but you have to look at the 20th century and see how even with 2 very large spikes in temperature between 1910-1930 and 1980-2000 there were large periods of down or flat periods like we are experiencing right now. This implies it is likely we will see similar flat periods in the remaining 90 years of this century. It is also hard to believe we will get spikes much more massive upward than the ones we had in those time periods of 1910-1930 and 1980-2000. Those are very steep curves to get us to 0.7 for the century. How do we get 3-6 TIMES that much if we have lulls like the last 10 years and what may be a 15 year lull? Shouldn't we assume at least one more lull like this in the rest of the century. That means that we have 70 years to get the 3 degrees or 7 decades of 0.43/decade increase. Not inconcievable but very very high and unprecedented. It just feels risky to say we "know this will happen" therefore I am skeptical. 0.43/decade is very high increase. We have seen a 0.6 decrease this year so it is certainly possible to have a sustained increase in a decade of this magnitude but to do it consistently over 70 years seems improbable without seeing more evidence.
The argument I've heard is that even if this is low probability of happening we should make big changes in our society and how it uses energy because the risk is huge IF it happens. The problem with this is that I don't believe the negative consequences either. The temperature of the earth has been rising since 1750 and every increase has been associated with positive improvements in life and the world. I see no compelling reason to believe that will change for the next degree or 2. Nobody has proved to me that todays temperature, not yesterdays and not tomorrows is the ideal temperature for life on earth. Everything in my gut tells me that warmth is good. Life likes warmth and heat. Most of the planet is now covered in ice. If you fly much you see this all the time. When flying to europe from california I fly over 5 thousand miles of ice covered land. The earth could stand a little higher temperatures without significant negative effect it seems obvious to me. What if canada was more arable or large parts of russia? What if we could get at resources under the north pole or sail easily between europe and the US? Would this really be catastrophic? It seems unlikely. Also, CO2 is a plant food and as you point out humidity and rainfall are up, not down. This means more water, more freshwater. Glaciers melting means more water. It is also per chance increasing the size of Bangladesh easily overpowering the effect of sea level rising.
On and on Daue the arguments of the "believers" of high sensitivity CO2 climate seem designed to support a political thesis not to advance science or humanity or life. They want to prove they are right not even to advance science but to advance a poltiical agenda. That is worrisome because it ties science to politics and may cause backlash on science. I personally think this is more important than any political agenda. If there is one thing I love is truth and science is the embodiment of mans search for truth. To corrupt that for political purposes is unworthy and damaging. I think you must agree.
Another series of numbered responses:
ReplyDelete(1) Saturn says: "While you and others claim the current data is within the normal variability the problem for me is that it isn't confirmatory."
Well, sure… of course it isn't. The whole point is that a ten year regression tells you very little. It fails to show that warming has stopped, and it can't show that it hasn't stopped either.
With longer windows of time, the confidence limits on slopes become much tighter. The last 20 years has seen a strong and unambiguous warming trend. Using HadCRUT3, the last twenty years show an increase of +0.186 C/decade, with 99% confidence limits from +0.149 to +0.224.
The last ten years show +0.05 warming, but the 99% confidence limits on slope are from -0.05 to 0.14. See the difference? Short periods of time are no good at all if you are just looking at trends or correlations. We don't use the last ten years to define a trend. The data won't support it; there's too much natural variation going on. OK?
We know there's a strong warming trend since 1975 or so. That's measured, to a very high level of significance indeed. There's excellent theoretical reason to think it will continue, and also that we will continue to see the same kinds of natural variation expected both by extrapolation and by theory. That's just the physics. It is also a falsifiable prediction; but it is not falsified by one ten year window; especially one that actually still shows warming.
(2) Saturn says: "Yet, what is damning about "your" science is how you insist beyond all reasonable argumentation that there is no doubt this high sensitivity exists."
There is a solid basis for confidence that the sensitivity is somewhere from 1.5C to 4.5C per doubling of CO2. So there is heaps of room for debate and argument, which goes on all the time. It's unlikely to be less than 2C, and very unlikely to be less than 1.5C. There is no rational argument at all for sensitivities less than this.
There are plenty of pseudoscientific arguments; such as Monckton's paper. Your own argument is confused… you mix up sensitivity and forcings. You speak of China and India, and aerosol pollution that helps to depress temperatures somewhat. That's a matter of forcings, not sensitivities.
Furthermore, such pollution has immediate and very serious negative health and economic consequences, so India and China can be expected, as they develop, to address it just as the west has done. This kind of particulate pollution cleans up much more easily, as the particles wash out of the atmosphere quite quickly; whereas CO2 does not. In other words, you are looking at a regional short term partial masking of the longer term greenhouse warming.
(3) Saturn says: "How could the oceans be getting cooler?"
The oceans are not getting cooler. At best, there is conflicting evidence, as I pointed out previously, with some evidence indicating strong warming, and some indicating about four years of almost constant temperature (Willis, and the Argos data). But in any case, just like for surface temperatures, there are variations going on, all the time, within the longer trends. The real issue is not that there are variations in the rate of warming, but that there is an as yet unexplained conflict between different measurement methods.
Did you read the links I gave last time? Here they are again: NASA, and Willis. They are short and easy to follow, and they are not just a denial of the effect. They are directly from the very people doing the measurements that suggest show no warming of the ocean over the last four years. Read them.
Put it in a nutshell. Oceans are not getting cooler – that report was a measurement error, since fixed. Even so, you can get some cooling of the upper ocean over short time spans (several years). This is expected from theory, and from models, and fits naturally observed variations. There's plenty of room to look at what is uncertain; and my guess is that the major cause for a lack of warming in the upper ocean will be variation in the rates of exchange with the deeper ocean. Either that, or another set of systematic errors in the Argos floats; which remains a real possibility. But if the difference in Argos and Grace/Jason data is real, and due to exchanges with the deep ocean, it is part and parcel of the effect of the ocean's "thermal inertia", which bound up with heat transfer to the ocean. Any such flux offsets a matching energy imbalance at the top of the atmosphere. When everything comes to balance again (as it must because of limited heat capacity available) then the balance will be taken up again by surface warming. This also is "just the physics". It means that there is a certain amount of warming which is "in the pipeline", and will eventually be realized even with no change at all to any forcings.
(4) Saturn asks: "Is there something different about measuring temperatures in the troposphere compared to here on the land?"
Of course there is! Each set of instruments have their own associated problems. The fact of measurement errors in radiosondes for the troposphere is definite. Quite apart from changes in the instruments being used over time, the instruments used in balloons are different from those used on the surface, as well as a difference that might occur to you about measuring from a drifting and rising balloon, and measuring from a station fixed at the same location with plenty of time to equilibriate, or to measure a daily maximum. There's been a lot of work on this, and sources of error specifically limited to radiosondes unambiguously identified. This isn’t some excuse to avoid the data. It IS the data. It's part of the whole deal of measurement in science.
(5) Saturn asks "I've never seem a "physics" statement of position on einstein. It's absurd. Why would we need such a thing?"
You need such things when there is widespread popular distortion and misinformation on some issue. The APS has statements of position on a number of matters where well established scientific fundamentals become a focus of pseudoscientific mischief or other forms of popular confusion, into which category the denial of global warming most definitely belongs.
For example, the APS has statements on perpetual motion machines, creationism, climate change, Kansas state board of education, and health effects of power lines.
(6) Saturn says: "I also want to emphasize again that as the temperature data continues to be moderate it makes the probability of 2 or 3 degrees by 2100 less and less likely even if the theory is correct."
No, it doesn't.
This is a really elementary bit of basic philosophy of science, but first we have to clear up the difference between a projection and a prediction. The numbers for 2100 are not exactly predictions, because they depend on assumptions about the choices made by humanity for future development and emissions. These choices are not predicted; they remain open and this is why it becomes such a political issue. What we collectively choose really does make a difference to what the world will be like in 2100.
But let's allow a particular scenario, to make things more concrete. The "A1B" scenario is one of the standard SRES scenarios, involving rapid economic growth, but with a balance between fossil fuels and other energy sources. Under this scenario, the IPCC projects a mean temperature change by 2100 from 1.7C to 4.4C, with 2.8C as the best estimate. (IPCC 4AR table SPM.1) This is a projected average for 2090-2099, wrt 1980-1999.
The first thing to note is that this is much wider than the 2-3 range saturn speaks of. The plain fact is that scientists DON'T have confidence in such tightly constrained predictions. Scientists are perfectly well aware of uncertainty and lack of knowledge, and this is consistently reflected in their work. Dismissing pseudoscientific objections is not the same as pretending to know all the answers!
Now to the philosophy of science bit, and the implications of the small warming slowdown in the last decade. The crucial point is that the projection is not based on correlations and extending a curve. It's based on the theory of climate and the underlying physics. Now as to whether that model is refuted by a slowdown that is only about 1.25 standard deviations below a trend… does this imply the model should be revised?
No, it doesn't; and as a physicist you should know that! The models already predict variation of this level. Models are NOT used to predict a specific series of temperatures. (And hence you don't give a temperature for 2100, but an average for the decade 2090 to 2099.) Weather is chaotic, you simply cannot predict the temperatures series year by year!
The way a model is really used is that you make a number of different runs, and the prediction is not any one of those runs, but the envelope of variation within the series can be expected to fall. The prediction is falsified when you get an observed series that is outside the range of variation given by the model. And you don't have that… not even close!
(7) Saturn says: "The fact that there is real reason to doubt 2-4 degree sensitivity. The lack of willingness to accept the theory isn't proven. It will take 50 years of sustained data collection for such a theory to even approach proof."
The evidence plainly indicates that sensitivity is in the range 1.5-4.5C per doubling, and probably within 2-4. There are some isolated lines of evidence for smaller values down to 1.5C; but that has to be balanced for other lines of evidence for larger values. There is, however, no credible line of evidence for values smaller than 1.5. Claims to the contrary are based on outright errors. I don't say that because of any refusal to look at the alternatives; but because this is what you see when you DO look at the purported alternatives.
The claim about 50 years is just silly. Science never gets absolute proof of things, but the current state of data and evidence is ample to show that the planet is warming; that the major cause of that in recent decades is an enhanced greenhouse effect driven by human activity, and that the planet heats up in response to elevated greenhouse levels, with a sensitivity that is greater than the base Planck response.
50 years of data will naturally nail down the sensitivity a lot more, but you don't need it to see the mathematical errors in bad arguments for stupidly low sensitivities, nor do you need it to get a high level of confidence in the bounds 1.5C to 4.5C. That's just not looking at the evidence we already have, or swallowing uncritically a lot of tosh and wondering why scientists aren't taking it into account.
The simple fact that there continue to be lots of real and substantial unresolved uncertainties gives the lie to the implication that scientists are just refusing to look at dissent. The problem is not that scientists refuse to look at the counter arguments. They HAVE looked at the counter arguments from those trying to undermine the basics, and quite properly identified them as nonsense.
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These comments are getting long, and I'm necessarily selective in what points I actually comment upon. I appreciate that you've been substantive, even though I think you've been wrong. If there is any one particular point I have not addressed and you think I should, feel free to single it out for my special attention. Thanks!
Re: Spencer: He uses frequency analysis over a short time span from satellites to calculate a sensitivity, and the time scale used pretty much assures that he's mostly measuring the immediate baseline response, not the feedbacks at all;
ReplyDeleteDuae, I looked at the latest charts from NOAA regarding temperature anomaly. For the period of 1941-2008 or nearly 70 years we have a total temperature variation of 0.4 degrees or 0.045/decade. At that rate over 100 years we would have a total increase of 0.4 degrees or 1/3 LESS than the increase of the last 100 years. This is not even an accelerating trend!!! The rate of temperature increase (without significant CO2 generation) was HIGHER than the post-war period in which CO2 production has massively increased.
How is that for facts, Duae? There may be disagreement about all the other proxies and what happened over time and what caused it but in the last 67 years the total temperature increase has been DECREASING! Now, I know you'll say I'm cherry picking. How can I be cherry picking over 70 years? Shouldn't the "monstrous 2-4.5 degree high sensitivity to CO2" be evident in some way in the last 70 years? What form of science are you using that projects massive changes when under the same conditions (1%/year increase in CO2) we've had 0.004degree/year increase for almost 70 consecutive years.
I know the period 1941-1975 is a problem because it was a 34 period of decreasing temperatures that happened during a period of massive increase in CO2 but this is "explained" by aerosols. I believed that explanation but it is starting to look suspect because the NAO and PDO phenomenon seem to explain these temperature variations better than aerosols, CO2 and all the other gobbledygook the IPCC came up with. The recent heating in the arctic is better explained by NAO than by CO2 and it explains the recent cooling in the arctic better than CO2.
Do you see yet how outrageous your claims that everything is right in dodge seems when presented with real indisputable data? You are telling us that even though over the last 70 years temperatures have been going up at 0.004C/year or over the last 110 years 0.006C/year we are to expect in the remaining 91 years of the 21st century that temperatures are going to go up 0.045C/year or MORE THAN TEN TIMES the rate for the last 10 years, the last 40 years, the last 70 years or even the last 110 years!!
Do you understand why we need more than you have given us about assertions you have "proved" this? It's unrealistic for anyone to believe this. It's a crazy theory to believe that with ocean temperatures on the way down or just flat, with the troposphere not responding very highly, with land temperatures plummeting in the last year, ice in the south pole and north pole both increasing, sea levels declining for 2 years now that suddenly we are going to go into a "science fiction" nightmare scenario of rapid unmitigated, unstoppable increase when we just had a 10 year pause.
I just cannot emphasize how unbelievable you and Hansen and Gavin appear these days. This is why questions are appearing and why the APS central committee on keeping its funding going from key government sources needs to re-issue its political proclamation that we "believe in serious global warming". The doubts are flying everywhere because the data is contradicting everything any of you ever said would happen (and frankly I said at one time would happen.) I no longer can believe this.
So, what I have concluded and continue to conclude is that CO2 is still a greenhouse gas. It is being put out by humanity in large quantities affecting its percentage of the atmosphere. It will capture extra heat. However, the atmosphere and oceans are incredibly complex phenomenon with enormous heat capacity. There are phenomenon we clearly don't completely understand yet that seem to be creating a negative feedback to the CO2. We are studying those processes and trying to figure out how they work. It is conceivable that temperatures will climb some amount, maybe 1 degree or at the outside 1.5 degrees or even a little more by 2100 but unlikely at this time it will get to 2 degrees let alone 3 or 4 or 5 or 6 as Hansen, Gavin and others have speculated or that models have guesstimated.
I understand fully well that you believe the physics supports a "high sensitivity" but you must understand it doesn't take a genius to figure how you can sustain this. It is clear you are able to sustain high sensitivity only because you have manipulated lots of parameters that you have no proof are what you say they are. Let me explain a little.
In order to have high sensitivity to CO2 it is necessary to incorporate reasons why temperatures varied as they did over the last 100 years. Particularly since 1900 there wasn't very much CO2 you ascribe 1/2 of the rapid heat increase in the early part of the 20th century to the sun. Then we assume aerosols create a large effect so we can explain the 1940-1975 temperature decrease (in the face of massive CO2 increases). All of that allows us to then ascribe the latest temperature surge to CO2. It is a carefully orchestrated plan that depends on many parameters and many unknown values. These values are played with in models till you get something that looks sort of like the temperature history of the last 100 years then you start jumping up and down proclaiming we have "proved" that there is high sensitivity to CO2. Yet your model of how things work depends on your assumption you know all the phenomenon affecting the environment, that you have picked the correct values for each of the forcings you are aware of. This is speculation. It is a theory.
I say that the theory may be right but one big thing working against it at this time is that it now predicts a very large asymptotic temperature increase that seems unlikely. The reason I would guess is that you have chosen a very high sensitivity to CO2 which causes the spiking temperature that seems unrealistic at this time given the behavior over the last 30 years or 70 years.
A more likely scenario is that CO2 has low sensitivity and that there is other behaviors and interactions that are pumping heat around the system that are contributing a lot to the temperature record over the last 100 years. In particular the NAO and PDO phenomenon appear to dominate temperatures over 70 periods pushing temperatures up and down over this period in a cycle. There is probably some residual CO2 effect that is pushing temperatures up overall but we also have to look at exogenous factors that could be adding heat to the system.
> Using HadCRUT3, the last twenty years show an increase of +0.186 C/decade, with 99% confidence limits from +0.149 to +0.224. The last ten years show +0.05 warming, but the 99% confidence limits on slope are from -0.05 to 0.14. ... We know there's a strong warming trend since 1975
The high sensitivity case Duae requires at this point a >0.45C/decade warming or 3 times your 20 year average and 10 times your 10 year average. As you must know choosing 1975 happens to correspond to the end of the last leg of the negative PDO and AMO cycles and the end of the cooling period from 1941-1975. It would be far more fair to include the 1945 data to be conservative and to include a full PDO/NAO cycle in the data. Picking a timeline corresponding to the start of the +PDO time period is unfair. What is more damning is that even if you include all of the data from 1975 and this cherry picked period for the high sensitivity case you still end up with only 1/3 of the needed rate increase to get to the high sensitivity CO2 scenario and to 2 to 3 degrees by 2100 on a doubling of CO2.
It is just unreasonable to imagine as we are going into the down cycle of the PDO and NAO cycles, with the oceans cooler, the sea level falling that suddenly we are going to go into a hyper accelerated trend of temperature increases. Yes, it's possible and maybe some people feel embolden enough to make such a prediction but it can't be mainstream to predict this.
It is indisputable the earth has been getting colder for 10 years. Not only ocean temperatures are flat (give you the benefit of the doubt here again) but it's been frigid everywhere. Southern hemisphere is friggin amazing cold. I saw a chart that showed that over the last 30 years the divergence between the northern and southern hemispheres has ballooned. The northern hemisphere has gone up 0.25 degrees in that time period but the southern hemisphere has plunged 0.5 degrees leading to a 0.75 degree difference. This is a massive amount of energy that has moved around. Why? There must be some reason? Just as there must be a reason for the PDO and AMO phenomenon. We know these things exist. We use the AMO to actually predict winds and storms in the atlantic with accuracy. The PDO accurately predicts the effects of La Ninas and El Ninos on the world. These theories are far better backed up by data, history and predictions being correct than AGW-IPCC theory and those models.
I suspect we will discover one reason why things haven't worked out for the AGWIPCC models has to do with their lack of physical understanding of these large unexplained phenomenon.
I suspect there are phenomenon and physics in these phenomenon that when we understand them better and integrate them into the models will provide a much better analysis of the worlds climate. Until the models explain why we have had a 10 year haitus in temperature increases and explain the NAO and PDO phenomenon and model them I won't believe the models or predictions from the models again. Even if the resulting models predict high sensitivity to CO2 after that I may reserve my faith in them until the temperature data of the planet seem to be coming back into compliance with the models.
Let's say you (and me) are right that some of the current temperature variation is caused by aerosols from pollution in China and India and also some upwelling of deep ocean cool water depressing temperatures this is very significant. The ocean has 300 times the heat capacity of the atmosphere. Just raising ocean temperatures 0.1C will be able to offset 30C of air temperatures. It may take thousands of years to warm the ocean enough for the high sensitivity CO2 effect to finally happen. We don't understand how this process of ocean currents and air heat exchange works obviously and this understanding could mean that heating is put off for thousands of years. That is critical because if the temperature increase is put off for just 200 or 300 years all the CO2 we put in the atmosphere will probably burn off. It means we have hundreds or thousands more years to solve the problem instead of the 10 days that Gore and Hansen claim we have to enact legislation!! Legislation that may emperil a billion people to a lower lifestyle and possibly death to solve a problem that we were wrong won't exist for 2,000 years or something.
I agree with "it's the physics." I don't think we understand the physics of all this nearly enough to claim we know much. We are at the very beginning of understanding this stuff. ( AS we are with many disciplines like genetics). The reason people want to seem MORE KNOWLEDGEABLE than they really are is because of the politics and I hate that. I hate that people will emperil science to satisfy a political desire. I believe that doing so will have massive implications on science. I am trying to say. We need to come clean. We need to say we don't really know. We need to study it. It is important to study but we can't tell you very many truths yet.
(1) Saturn says: " For the period of 1941-2008 or nearly 70 years we have a total temperature variation of 0.4 degrees or 0.045/decade."
ReplyDeleteAll global datasets show temperatures from 1941 to 2007 overall increasing at 0.08 or 0.09 C/decade, NOAA data included. If you tell me what data you used, I may be able to help identify how you got a different number. Feel free to use links.
The NOAA website provides a recent GHCN-ERSST dataset here. If you stick to the GHCN-ERSST dataset you'll be fine; but there are bugs in their implementation of HadCRUT2. (I told them about this problem weeks ago, and it still isn't fixed.) HadCRUT data is better viewed at the Hadley Center website, since they maintain that data. The NOAA interface can be confusing; if you want the annual data, make sure months have the range January to December; and then pick any range of years. You can look at plots, or download and play with numbers.
(2) Saturn says: "At that rate over 100 years we would have a total increase of 0.4 degrees or 1/3 LESS than the increase of the last 100 years. This is not even an accelerating trend!!!"
Your numbers for slope all seem to be wildly incorrect. The slope over the last 100 years is about 0.07, which is a bit less than the slope over the last 70 years. The biggest acceleration of warming was from 1975 onwards.
The 1940s show a significant drop in temperatures. Part of the reason for this is aerosol pollution, which has negative forcing. Such pollution washes out of the atmosphere quite quickly once you stop emitting it, and a major clean up in emissions mid century resulted in much "cleaner" emissions, which reduced problems with smog and acid rain and so on, though it has no effect on CO2.
(3) Saturn says: "How is that for facts, Duae? There may be disagreement about all the other proxies and what happened over time and what caused it but in the last 67 years the total temperature increase has been DECREASING!"
I think you've mixed up your analysis; or you are using the wrong data at NOAA. You speak of the "total temperature increase" as something that "decreases". That sounds like an attempt to go to a second derivative.
You and I have both recognized that there was a start to strong warming from about 1975, and before that it was not warming much, if at all. Further back to the 1940s it was cooling. How can you now say that the rate of increase is decreasing? I don't get it; that makes no sense. If you tell me how you get your numbers, I might be able to help sort it out. I use linear regression, and check my results on a couple of different datasets.
Here's one way to show the accelerating warming trend; you'll need to get the data into a spreadsheet first. Calculate the slope over a 10 year moving window. Then see if those slopes increase, or decrease, with time. For moving windows, you have to calculate the regression explicitly; not get it from a chart. With Excel, use the LINEST function. Using HadCRUT3v annual timeseries, from 1941 to 2007, here's what I get:
(a) Simple regression line over the whole period: +0.09 C/decade warming.
(b) Floating ten year windows, from 1941-1950 through to 1998-2007, average +0.087 C/decade warming, but with a standard deviation of 0.16 C/decade. That is; lots of variation between different ten year windows.
(c) Plot a regression line over the series of slopes for the ten year windows! This shows an increase in the rate of warming of about +0.06 C/decade/decade.
The period from 1941-2007 shows overall strong warming and also a strong increase in the rate of warming. This is "just the maths".
(4) Saturn says: " I believed that explanation but it is starting to look suspect because the NAO and PDO phenomenon seem to explain these temperature variations better than aerosols, CO2 and all the other gobbledygook the IPCC came up with."
The aerosol effect is not gobbledygook, and neither is the notion of oscillations having an effect. The idea of one "replacing" the other is… odd.
I'm enthusiastic about work on the oscillations; I think it offers some good prospects for improving models. I don't think anyone working on it directly proposes to replace the definite and known effect of aerosols. It can't explain a large trend such as the last thirty years, for a number of reasons, but that is not a criticism of the work, because no-one is seriously proposing such a thing. (Isolated uninvolved outsiders not counted; there are some onlookers who are capable of saying almost anything.) This work is potentially a way of sorting out some of the second-order trends that so far I have called "natural variation". If we can model those variations better, great!
However that works out, simply dismissing the definite measured cooling effect of aerosols as "gobbledygook" is very telling. You really are having awful problems with dealing with very basic physics here.
The cooling effect of aerosols has a definite physical basis; by raising albedo. The effect is also measurable; this is how volcanoes cool things down, for example. The reduction in aerosol pollution in the post war period is basic data.
(5) Saturn says: "You are telling us that even though over the last 70 years temperatures have been going up at 0.004C/year or over the last 110 years 0.006C/year we are to expect in the remaining 91 years of the 21st century that temperatures are going to go up 0.045C/year or MORE THAN TEN TIMES the rate for the last 10 years, the last 40 years, the last 70 years or even the last 110 years!!"
Come now, Saturn, settle down. Those are your numbers, not mine. Don't put them into my mouth. What I am telling you is written in my own words.
I can calculate the trends, if you like. I'll use HadCRUT3v again; other datasets may have small variations, but large differences would suggest one or other of us has messed up in our calculations. It happens. Here's what I get, from HadCRUT3v annual series:
(1) Last 110 years, 1898-2007. trend of +0.069 warming.
(2) Last 70 years, 1938-2007, trend of +0.080 warming.
(3) Last 40 years, 1968-2007, trend of +0.155 warming.
(4) Last 20 years, 1988-2007, trend of +0.198 warming.
(5) Last 10 years, 1998-2007, trend of +0.087 warming.
Note that as the periods get short, the effects of natural variation get large. There is a slow down in the last ten years, certainly; but we've had even larger slowdowns than during the last 40 years. The ten-year slope went negative (just) from 1977-1986, and then almost did it again over 1987-1996. But two years later, 1989-1998 was one of the largest trends!
The obvious slow down in the last ten year window does not yet have sufficient significance to conclude that the long term warming trend is slowing down.
(6) Saturn says: "In order to have high sensitivity to CO2 it is necessary to incorporate reasons why temperatures varied as they did over the last 100 years. Particularly since 1900 there wasn't very much CO2 you ascribe 1/2 of the rapid heat increase in the early part of the 20th century to the sun. Then we assume aerosols create a large effect so we can explain the 1940-1975 temperature decrease (in the face of massive CO2 increases). All of that allows us to then ascribe the latest temperature surge to CO2. It is a carefully orchestrated plan that depends on many parameters and many unknown values."
That sounds like an accusation of lack of integrity. Are you serious?! Disagree if you must; but you have crossed a line here. There is no basis for these rather poisonous little insinuations.
Climate models are based on physics. (Just the physics, again.) They don't use curve fitting to a particular temperature record. Any forcing effect, from the Sun or aerosols or greenhouse gases or anything else, has to match up with independent data for that forcing. Total solar irradiance really was increasing over the first half of the twentieth century; the modelers don't come up with that. Aerosols really did increase in the middle of the century, and then became cleaned up somewhat. (This was part of fixing the "acid rain" problem.) Greenhouse gases are measured; you can't adjust the levels to fit temperature.
The forcing effects of these factors have to be physically sensible as well. The forcing from the Sun comes fairly directly from irradiance levels. The forcing from greenhouse gases is calculated quite accurately by physicists, not by modelers. Aerosols I am not so sure about; but they alter albedo, and there are tight constraints on what kinds of alterations are physically credible.
You most certainly don't add a bit of Sun here and a bit of aerosol there to fit a curve, and you are WAY out of line with those insinuations. These are measured changes, and their effect on climate is just the physics.
(7) Saturn says: "As you must know choosing 1975 happens to correspond to the end of the last leg of the negative PDO and AMO cycles and the end of the cooling period from 1941-1975. It would be far more fair to include the 1945 data to be conservative and to include a full PDO/NAO cycle in the data. Picking a timeline corresponding to the start of the +PDO time period is unfair."
You miss the point. Of course 1975 is chosen precisely because it is the start of a strong warming trend. I've said that explicitly; nothing is being hidden. Trends over the twentieth century are not simple linear effects. Roughly speaking, there is a strong warming trend from 1910 to 1940, then a sharp drop to 1950, then a wavering level from 1950 to 1970, then a strong rise up to the present. If you want to know the warming rate over recent decades, you should fit a line from about 1975. Going further back than this no longer matches well with a linear trend line.
This is the pattern that has to be explained by models; and the explanation cannot just speculate about a bit of NOA here and a bit of aerosol there. You need a physical model which reproduces the pattern when it takes the forcings as inputs.
There's also a slow down in the last couple of years, but it does not yet have enough significance to indicate another significant shift. It could turn out that way, but you'll have to wait a few years yet to tell. After all, twice since 1975 we've had even bigger "slowdowns" than this.
(8) Saturn says: "It is indisputable the earth has been getting colder for 10 years."
Other than the fact every data set shows a warming trend from 1998-2007 when you actually do the calculation, of course.
> All global datasets show temperatures from 1941 to 2007 overall increasing at 0.08 or 0.09 C/decade, NOAA data included
ReplyDeleteI believe you're looking at 20 year running averages or something. I'm looking at absolute peak temperature of 1941 compared to 2008. It's about 0.4 degree difference.
0.08*70 = 0.56 ... the entire period of 1900-2008 has only 0.7 increase yet we know the period 1900-1941 went up 0.4 degrees so there is seriously wrong with your arithmetic because 0.4+0.56 != 0.7. The fact is as I pointed out the period 1900-1941 had a FASTER acceleration of temperature than the period 1941-2008 which is the period of rapid CO2 production. That seems odd.
But once again, it isn't even necessary for me to argue this. In order for us to get the 2-4.5 or 3 degree temperature rise you predict and Hansen and Gore ... requires a slope of at least 0.45 /decade or 5 times the period of 1941-2008 you stipulate. It's still ridiculous.
Since we've already lost almost 10 years in the 21st century and the slope is negative for this last 8 years (again forget 10 years if you want to argue over +0.004 or 0.000 or -0.004 it makes no difference. We are so far from the necessary temperature increases it is laughable.
You must realize that we've never experienced 0.45 degree/decade increase in the history of temperatures we have throughout the 20th century. It is multiple times the temperature increase rate we've ever experienced and you are telling me you expect it to do this for 92 consecutive years without stopping!!!!! If we get the current haitus continuing much longer or if magically surprise surprise we were to get another 10 or 15 year "unexplained" haitus then we'd need even larger rates of temperature increase to compensate. It's unbelievable for a number of reasons chief among them that before I accept such alarmist predictions I need more than a theory. There are too many theories possible and possible explanations we don't even know about.
Among the things I haven't mentioned which make this so extremely improbable is the logarithmic nature of temperature sensitivity to CO2. All the physics says that temperatures go up as the log of the CO2. What this means as you know (and as the IPCC modeled in all their predictions) is that most of the temperature increase occurs EARLY in the CO2 increase because subsequent increases in CO2 cause less and less forcing unless CO2 output keeps increasing exponentially as it has for the last few decades. This is unlikely as I've said before becuase of natural resource limitations and natural technology improvements but in any case both the IPCC and physics agrees that if we are going to see temperature increases they should be front loaded - i.e. we should be seeing them NOW not later. Since we've been increasing CO2 output at an exponential rate of 1%/year of doubling every 70 years or so well above the predicted trend of the IPCCs "worst case" we almost surely should be seeing some response in temperature ESPECIALLY if there is high sensititivity as you predict for CO2 this would be the time we'd be seeing this increase. This means the rate might have to be much higher than even 0.45 to get the kind of increase you need to show a 2-4 degree sensitivity to doubling. We would need to see the temperature increase 3 or 4 degrees in the next 70 years not 100 years or we should be seeing that happening. At the current rate of CO2 output the models should probably be predicting 1 degree/decade or more to achieve the high sensitivity scenario. We're not, Duae. There is no way to massage the data to get this. You can't interpolate winds in the troposphere and tell me we're seeing this or anything like it. It's dead. Don't you see it? There is no way the high sensitivity can be right.
For high sensitivity to be right at this point is like being in the 9th inning of a baseball game and being 15 runs behind and hoping to win the game. It happens. It's possible but incredibly unlikely.
That is simply the facts Daue. We're not seeing that kind of temperature increase at all. In fact the last year has been blisteringly cold. We have have COLDEST EVER recorded summer in Alaska. South America and Antarctica are also in record territory for the last century!!! They had the first snowstorm in Buenas Aries recorded ever. The snowfall and coverage on Kilamanjaro is higher than in 40 years and what used to be a poster child for declining glaciers has become the opposite.
I can't believe you're actually arguing temperatures are up for 10 years. If they are it is infinitessimal and a pure cherry picking of the dates because if you look at the charts it's pretty clear that past 1998 and the huge El Nino of that year temperatures have pretty much been sloping down and I know you've seen the same temperature records I have which show a continuous trend downward with the last 18 months as being on a slope downward that is frightening.
The data I use is: http://www.ncdc.noaa.gov/img/climate/research/2007/ann/global-jan-dec-error-bar-pg.gif which is jan-dec data. I don't need to download data to see directly from the chart the temperature anomaly in 1941 is >0.1 and the temperature anomaly in 2008 is <0.6 closer to 0.4 difference so I can't imagine how you get 0.7 degree in that timeperiod unless you are doing some rolling average or something. The fact is as everyone knows the entire increase in the 20th century is 0.7 degree and it wasn't all concentrated in 1941-2008 so you are wrong. The slope in that period is closer to 0.0045/year not 0.009.
> The 1940s show a significant drop in temperatures. Part of the reason for this is aerosol pollution, which has negative forcing
I used to believe this made sense, Daue. However, after looking at the NAO and PDO charts I've become convinced that a large part of the 1941-1975 cooling was caused by the repetitive moving of heat in the atmoosphere that has occurred every 35 years or so. I don't know why there is this cyclical phenomenon but they are better documented and explain the lull from 1941-1975 better than aerosols. I'm not saying aerosols didn't also play a role but it is clear to me that we have to cut the sensitivity to aerosols substantially because of this cyclical phenomenon. The NAO and PDO phenomenon appear irrefutable and need to be included in the models. They will drastically reduce the sensitivity to CO2 as well. This makes more sense and explains current temperatures better than the AGWIPCC models.
> You and I have both recognized that there was a start to strong warming from about 1975, and before that it was not warming much, if at all. Further back to the 1940s it was cooling. How can you now say that the rate of increase is decreasing?
What I am saying is that the period from 1900-1941 saw a 0.3 increase in temperatures which is larger rate of increase than the 0.4 increase over the subsequent 70 years. Check it out. All the charts show a substantial increase from 1900-1941. In fact they show an increase in temperature from 1750 to 1941 when SUVs weren't manufactured and Ford Motor company didn't even exist. However, I'm unwilling to discuss data before 1900s because there are constant arguments about tree rings vs leather buckets and engine inlet temperatures and ice cores and island heat effects and all this other stuff.
> Using HadCRUT3v annual timeseries, from 1941 to 2007, here's what I get:(a) Simple regression line over the whole period: +0.09 C/decade warming.
(b) Floating ten year windows, from 1941-1950 through to 1998-2007, average +0.087 C/decade warming, but with a standard deviation of 0.16 C/decade. That is; lots of variation between different ten year windows.
YET all the amounts are 5 times to 10 or 15 times less than required to get to high sensitivity temperatures. You do understand that if we return to the 0.09C/decade you calculate you are only going to get about 0.9 degree for the 21st century which is the same as the 20th century and is a factor of 3 less than "high sensitivity". Once again this assumes that it is uninterupted temperature increase and that our CO2 output slows to be doubling every 100 years instead of every 70 years as it is now.
> The period from 1941-2007 shows overall strong warming and also a strong increase in the rate of warming. This is "just the maths".
Duae, it doesn't show strong warming because even your (notice here again I concede your point because it makes no differnce to the end result) 0.09 isn't strong warming. 0.45 would be strong warming. 0.09 is the same warming we got for the last 100 years which is the same warming we've been getting for hundreds of years since the last ice age ended and is inconsequential.
High sensitivity means 2-4 degrees which is about 3-6 or more times > rate of warming than we've been experiencing even during the 1980s and 1990s. It's simply unlikely, Daue. Extremely unlikely. It's not scientific to make such unlikely predictions. It is more religious or shooting craps at the crap table. Scientists aren't crap shooters and don't believe in divine intervention of the heat gods to suddenly warm up the oceans massively and to put fire into the atmosphere that apparently we are having a devil of a time finding except by looking at winds and extrapolating or something. If it was warming anywhere near the 0.45C/decade you need we would have no problem finding all that heat accumulating someplace. It would be evident that heat was being massively accumulated somewhere and it should be easy to find it. Instead we're trying to find out where all the heat went. Did it sneak into the deep ocean below our ARGO probes 6,000 foot depth. Is it hidden in blowing winds in the near massless troposphere?
What I learned in stock market analysis is a simple rule. To get from 100 dollars a share to 200 you have to go through 110, 120, 130 etc... If we are going to get to 3 degrees warmer by 2100 we have to first get 0.45 degrees warmer and 0.9 warmer and 1.35 warmer etc... we can't get there by sitting at the same damn temperature for 10 years even if it is a higher temperature than we've seen in some time it still has to go higher faster and we just aren't seeing that and we aren't seeing the "volumes" to continue the stock analogy to drive the stock price or the temperature up.
> However that works out, simply dismissing the definite measured cooling effect of aerosols as "gobbledygook" is very telling. You really are having awful problems with dealing with very basic physics here.
I'm sorry for that. I have a strong bias against models. As a computer scientist I don't believe you can build models of the earth easily. We've been trying to do that for the climate and weather for many years to no avail. I think there are good reasons to believe the problem is extremely complex and that we have a very simplistic model right now that really has zero chance of working. I think it is likely in 50 years we'll have progress but not much before.
> The obvious slow down in the last ten year window does not yet have sufficient significance to conclude that the long term warming trend is slowing down.
I don't care if the trend slows down or stays the same. If we are going to get to 2 degrees for a doubling of CO2 or greater you need temperatures to start accelerating now and very fast in unprecedented ways that are unscientific.
> You most certainly don't add a bit of Sun here and a bit of aerosol there to fit a curve, and you are WAY out of line with those insinuations. These are measured changes, and their effect on climate is just the physics.
Duae, it is most certainly the case that the forcings are calculated by the "reverse method" as the IPCC calls it. This is "fitting a curve." Duae, the effect of corruption of data is subtle. It's not just as simple as the "fitting" I described. The mere idea that you know the shape of historical curve of data leads you to build models which you know will fit that data even if you don't actually plug numbers in. This is corruption of the data too. However, it is a FACT that the IPCC clearly states they use the reverse method to calculate the forcings for aerosols and other factors. I don't know why you are trying to deny it. They are continually "improving" the models. By definition the mere process of improving is to take how the data and models fail to coincide come up with some modifications and incorporate those changes in the models to they "fit" the data. I don't understand why you resist this. Past data cannot be used to validate the models. Only data that has never been seen before is valid. Since 2001 when the models were issued they have completely failed to predict the data since then. That is catastrophic in my opinion or at least puts doubts and does not confirm the theory leaving it completely unverified.
Now some of the recent papers have looked at data I believe the original model authors had no access to and probably made no attempt to incoroporate into their thinking. This data was then compared against models and the models were found completely unpredictive. If the data and models had coincided it would have been mildly interesting and positive for the models but not confirmatory in my opinion. However, the lack of conformance is damning because like string theory you can show lots of calculations which string theory seems to match real world data fine. Unfortunately so do many other theories. Therefore, string theory remains a theory and the nobel committee refuses to grant a nobel prize to its authors because nobody is sure string theory is right. I would say the models are less confirmed and maybe contradicted because unlike string theory the data doesn't contradict string theory. Data does contradict the models.
> This is the pattern that has to be explained by models; and the explanation cannot just speculate about a bit of NOA here and a bit of aerosol there. You need a physical model which reproduces the pattern when it takes the forcings as inputs.
Sure. I think this is a 50 year effort that's all. The current models don't work and aren't likely to work. It would be astonishing if they did and every study of them has shown they don't work.
Daue, if you look at the chart below:
ReplyDeletehttp://www.climateaudit.org/?p=3405
regarding the movement of heat from southern to northern hemisphere it is amazing. Clearly the models never picked up this amazing heat movement. For some reason the north has become 0.75C hotter over the last 30 years compared to the southern hemisphere.
How could the models miss this huge heat movement? Why would we be having a hemispheric bias of such magnitude?
I suppose there could be many reasons but it does make one think that it has something to do with the sun because the most obvious way to get one hemisphere to heat more than another is if the light is pointing stronger at it. If the earth is in an orbit or is precessed so that it is tilting the northern hemisphere slightly more to the sun over the last 30 years then this would say that the sun is having a large effect on climate something most physicists including me would have trouble understanding given that solar irradiance and orbits are well understood and measured. Nonetheless, there it is. One wonders what other large factors and effects the models miss and didn't predict? Ocean upwelling of course is one that we might be able to make advances on with the ARGO system.
I am excited to think we are learning all this stuff, Daue. I am always amazed how little we really know even though we think we are so smart. It is common in mans history to take a little scientific knowledge and extrapolate that we know more than we do.
I think some scientists are over exploiting the AGW hysteria for financial benefit or to get contracts. Some are politically motivated and want the science to match their philosophy badly. Others are truly convinced something is going on and are probably naive like scientists have been over the years about the complexity of things. I am always astonished by the story of stomach ulcers and how this one researcher was unable to get funding and to get to speak at conferences because of his bizarre theory that ulcers were caused by a bacterium. At the time he was shunned as an idiot because everyone knew that ulcers were caused by other reasons.
There is a reason scientists need to remain skeptical and to consider new explanations all the time. We really don't know as much as we pretend.
I've rearranged the order of these replies to suit my order of response. Saturn's comment was ordered differently.
ReplyDelete(1) Saturn says: " The data I use is: http://www.ncdc.noaa.gov/img/climate/research/2007/ann/global-jan-dec-error-bar-pg.gif which is jan-dec data. I don't need to download data to see directly from the chart the temperature anomaly in 1941 is >0.1 and the temperature anomaly in 2008 is <0.6 closer to 0.4 difference so I can't imagine how you get 0.7 degree in that timeperiod unless you are doing some rolling average or something. The fact is as everyone knows the entire increase in the 20th century is 0.7 degree and it wasn't all concentrated in 1941-2008 so you are wrong. The slope in that period is closer to 0.0045/year not 0.009."
Well, that sure is the GHCN-ERSST dataset. Thanks. I strongly recommend you go to this link, which I have given previously as well. It will let you make your own plots, look at trends, and also download the numbers. There's one point to beware. The numbers are given as "anomalies", or temperature differences; and your graph is aligned slightly differently. When you download the data, you'll find the numbers are all about 0.08 less than on your graph. It simply to do with whether data is aligned to a 1901-2000 baseline, or a 1961-1990 baseline. All the slopes and differences are unaffected. When exploring, make sure you use Jan and Dec and the start and end month, and that you use GHCN-ERSST, not the other sets.
There's no 2008 there yet; the last year in that series is 2007. Here are the last ten values, which are from 1998 to 2007, as they appear in the graph you've linked.
0.57, 0.38, 0.35, 0.48, 0.55, 0.55, 0.52, 0.59, 0.53, 0.54
The largest temperature there is for 2005. 2005 was the hottest year ever; but so close to 1998 as to make the difference insignificant. 2007 is only 0.03 degrees less than 1998; but everything less than 0.5 is over earlier in the series. This is an exceptionally clear case of an increasing series, with one high value at the start, followed by the three lowest values. Overall, that's a strong upward trend, as there is more weight to the right than to the left.
Draw it for yourself on a bit of graph paper where you don't have the blue smoothing line or error bars, and see how it looks; or try a plot with the advanced page. It will tell you that the slope is warming for 0.11 C/decade, but with low significance. (To make matters worse, there's a bug in their calculation of the slope. It's really 0.13. Caveat Emptor.)
(2) How to calculate a trend. Saturn says: "I believe you're looking at 20 year running averages or something. I'm looking at absolute peak temperature of 1941 compared to 2008. It's about 0.4 degree difference."
The method I am using is called linear regression. This is a basic tool for calculating slopes in data, and you'll find it used pretty much everywhere in science or statistics. What you are doing is not merely a different technique. It's essentially meaningless.
The correct method is to fit a straight line to be as close as possible to all your data points., and check the slope of the line. If you don't know what I am talking about, then most of my previous comment must have been pretty hard to follow! Sorry. There are lots of tutorials about this if you want to look it up. Linear regression. I recommend it.
For example, the slope from 1941 to 2007 is most definitely 0.081 C/decade, in this data set. Just look to see where the line of best fit should fall; it should be intuitively obvious from the shape of the curve that it will pass well under the 1941 high point, but rather closer the 2007 end point. Hence the best fit line is a bit steeper than a line between end points.
(3) Saturn says: "0.08*70 = 0.56 ... the entire period of 1900-2008 has only 0.7 increase yet we know the period 1900-1941 went up 0.4 degrees so there is seriously wrong with your arithmetic because 0.4+0.56 != 0.7. The fact is as I pointed out the period 1900-1941 had a FASTER acceleration of temperature than the period 1941-2008 which is the period of rapid CO2 production. That seems odd."
You've chosen a high point to start from, so of course the line of best fit is going to pass below your start point, which means the 0.4 end to end rise is expected to be less than the rising trend. And so it is. Comically, if you insist on using the end to end method you'll find the rise from 1900 to 1941 is 0.17; not 0.4.
It's very easy to fool yourself by playing games with your eyes and picking out convenient years to prove anything you like. A disciplined use of basic statistical methods will help avoid the pitfalls. It's also essential if you want to be taken seriously by working scientists. None of this is specific to global warming; its basic maths used the same way right across every field of science.
To find a trend over a long series of data, use regression. There are also statistics to check how good a fit you have. To compare the start and end, without caring about the middle, then you should take some kind of average at each end point, to avoid problems with outliers and noise, and take a difference between those.
Using averages over a decade, GHCN-ERSTT rises by about 0.3 from the 1900-1909 decade through to 1940-1949, and then by about 0.45 to 1998-2007; for a rise of 0.75 in total. The trend, on the other hand, is about 0.063 C/decade.
The causes of change are, of course, not limited to CO2. Over the first half of the century, the solar constant increased by about 0.8 W/m^2. (From a standard data series by Lean, 2000). I won't go through all the numbers, but basically that should be expected to account for about 0.1C, leaving 0.2C for other forcings. Could be more or less, depending on climate sensitivity, which is not well known. But if ridiculously low sensitivies are chosen, then we have a problem, because it would mean that the solar 0.1C drops below 0.05C; and leaving 0.25C for other forcings, which also need to be stronger to overcome the insensitivity.
In the latter half of the century, the Sun has held much steadier. With realistic notions of climate sensitivity, the other forcings… mostly greenhouse… have to explain 0.2C prior to the 1940s, and 0.45C afterwards. Not so odd after all.
(4) Saturn says: "In order for us to get the 2-4.5 or 3 degree temperature rise you predict and Hansen and Gore ... requires a slope of at least 0.45 /decade or 5 times the period of 1941-2008 you stipulate."
To pick a nit… I don't predict. I sometimes calculate consequences of certain assumptions; those are called projections. But there is still a heap of scope for choices than will make a difference, and I don't predict those. There are also large uncertainties, so all my calculations for possible alternatives in the future usually have some range of possibilities, not definite predictions. Just a clarification on my approach.
IPCC 4AR projections are sometimes given wrt 1980-1999; so we've already got nearly 0.3C. 2.7C more, and that is a 3C rise. To get 2.7 degrees from now to the end of this century requires about 0.3C/decade; which is substantially more than the 0.18 or so seen since 1975, when the current spate of warming got going.
(5) Saturn says: "Among the things I haven't mentioned which make this so extremely improbable is the logarithmic nature of temperature sensitivity to CO2."
It's why we always speak of doubling CO2. Each doubling has about the same effect. It's one of the basic formulae we all are using. You can't use the log argument to reduce numbers given by me, or the IPCC or the models. This is already taken into account in every projection you see.
For example, an amount of CO2 added at the start of the last century has something like 30% more effect than the same amount of CO2 added at the end.
The effect of doubling CO2 is around about 3C. It could be 2C, or it could be 4.5C. If you are doing risk analysis, you should look at a worst case. If you want a best estimate, you use 3C. The increase from 280ppm pre-industry to the current 385 is worth about 3*Log2(385/280) = 1.38 degrees. However, that is an equilibrium response. If CO2 levels were frozen at current levels, there would still be another half a degree or so of temperature rise over the next few decades as the ocean slowly heats up and restores the energy balance at the top of the atmosphere. If CO2 levels rise to 560ppm, that is roughly 3C rise over pre-industrial times total, or 2.3C more from the present, for the best estimate of sensitivity.
There's a fair bit of uncertainty in that number; it could be that there's only 2C temperature rise in total, which means another 1.3C from the present. Some of the consequences may be expensive; but all up it is not something that would worry me much. Another 2.3C is more serious; and that's the best estimate. A worst case, in this scenario, would be another 3.8C, which would almost certainly be very bad.
(6) Saturn says: " the slope is negative for this last 8 years"
Still in search of something I will agree is negative? The trend in your data set for the last eight years is 0.2C/decade warming.
(7) Saturn says: "At the current rate of CO2 output the models should probably be predicting 1 degree/decade or more to achieve the high sensitivity scenario. We're not, Duae. There is no way to massage the data to get this. You can't interpolate winds in the troposphere and tell me we're seeing this or anything like it. It's dead. Don't you see it? There is no way the high sensitivity can be right."
How on Earth did you get 1 degree per decade? All I can see, frankly, is that you aren't much good at maths; or else somehow not applying yourself.
Here's a calculation for you. We'll assume CO2 gets to 560ppm, which is double pre-industrial. It's now 385. The high sensitivity increase in temperature from right now is 4.5*Log2(560/385) = 2.43C. If temperatures increase at a constant rate from 2008 to 2100, that is 0.26C/decade. It's a little bit more than at present; but not massively so. We have often had ten years with a greater swarming trend than this.
But wait… temperatures have only gone up by 0.7C since pre-industrial times. There seems to be 1.37C missing! This mainly because of the slow response of the ocean to temperature change. Assuming high sensitivity, we have a situation where the Earth is in an energy imbalance, with the difference being taken up as the ocean takes up heat. This is the meaning of heat "in the pipeline". It may be many decades before the ocean warms enough for this heat to be apparent on the surface.
To maintain a constant rate of forcing increase, the CO2 level has to rise exponentially, because of its logarithmic effect. The increase required is a bit over 45% in 92 years, which is a 0.4% increase in CO2 concentration each year. The current rate of increase is a bit more than 0.5%.
The scenario is quite plausible. The rate of temperature increase is not actually much larger than what has occurred recently; and if we take into account the ocean's lag in the whole system, then the rate of temperature increase should be reduced, as it takes longer to come to full effect. In other words… the rates of temperature increase and CO2 increase right now are both consistent with high sensitivity and a doubling of CO2 by the end of the century.
To give an idea of the effects of logarithmic CO2 increase, let CO2 increase linearly, rather than logarithmically. The rate of increase is (560-385)/92, or 1.9 ppm/year. That's STILL less than the current rate of increase.
Let's underline that. A linear CO2 increase is 1.9 ppm/year, to get to 560 by the year 2100. An exponential CO2 increase is 4%/year, which would be initially about 1.6 ppm/year, and 2.3 ppm/year by 2100. That logarithm effect matters, but it is not making as much difference as Saturn thinks.
The atmospheric CO2 increase measured in 2007 was 2.17 ppm
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(8) Saturns says: "However, it is a FACT that the IPCC clearly states they use the reverse method to calculate the forcings for aerosols and other factors. I don't know why you are trying to deny it. They are continually "improving" the models. By definition the mere process of improving is to take how the data and models fail to coincide come up with some modifications and incorporate those changes in the models to they "fit" the data."
It's a bit like survival of the fittest, really. But seriously, this is what you do in science. Falsification is how you get rid of what doesn't work. It results in theory well fitted to evidence; but the process of falsification and elimination is different from the process of tuning or curvefitting.
As for the reverse methods… of course! Nothing I said was intended to deny that. The aerosols in particular are an example where reverse methods are applied. This is a form of tuning; but only at a very crude level. Basically, you propose a strength of the effect, but you can't just make aerosols strong here and not there. You also cannot make the effect stronger, or weaker, than reasonable. Hence, in my previous post, I said "there are tight constraints on what kinds of alterations are physically credible". This is actually a direct reference to the reverse techniques and the constraints under which they must work.
On the other hand, the big one is greenhouse gases. There's pretty much no room for adjustments here at all. The strength of the forcing follows from basic physics. The concentrations over time are known. There's not much for a modeler to play with; they just have to represent the known physics and known emissions and fire it up.
Greenhouse gases act to absorb thermal radiation, which heats up the atmosphere. The effect is definite, and very well quantified. The overall response of climate is a tough nut to crack, but it is also well constrained by both theory and evidence. Hopefully we will be able to constrain it further beyond limits that are currently known. But the limits we do know are well founded. Ideas for very insensitive climate and negative overall feedback are invariably nonsense. Ideas that the very sensitive climate is easily falsified by some easy drive by sophomoric reasoning are invariably nonsense as well.
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Added as a late revision.
(8) Saturn says: "… regarding the movement of heat from southern to northern hemisphere it is amazing. Clearly the models never picked up this amazing heat movement. For some reason the north has become 0.75C hotter over the last 30 years compared to the southern hemisphere."
What!? Of course the models pick this up. It is a consistent feature of the models that they do predict precisely this difference, and for obvious simple physical reasons. Once, again, "It's the physics, Simplicio".
The major physical reason for the difference between hemispheres is that the ocean responds much more slowly than the land to rising temperatures and the Southern Hemisphere has a lot more ocean. A second significant reason is sea-ice feedbacks. The North pole is sea ice; the South pole is an ice cap. When sea-ice melts, the Arctic albedo drops, which means more sunlight gets absorbed and temperatures are pushed even further. It's a simple positive feedback, which is far stronger in the Northern hemisphere. Climate models, which are based on the underlying physics, show this effect very strongly.
Simply asserting that models don't pick this up is the very opposite of skepticism. A skeptic might reasonably wonder whether or not models pick this up, and be in a position to learn something when finding useful new information on the matter. But jumping to wild presumptions about incompetent modelers is just naïve credulity.
Here's a link to a page where you can look at how an important NASA model predicts (or retrodicts) the response to known forcings: here. There's a wealth of information about the forcings, and about how the model responds to them. There is also a very detailed associated paper, from 2007, linked at the top of the page.
You can look at the trends from 1979 to the present, distributed across latitudes, and you will see the same strong warming in the northern hemisphere, substantially weaker in the south, which is a feature of the observational record that you linked.
Furthermore, this NASA page really is giving you the model output; NOT observations. Read the paper for even more details and comparisons with observations. There are quite a number of substantial differences between the model and the observational record, to do with rainfall and pressure gradients and all kinds of other climate variables. In particular… this model does not capture the peak-and-dip pattern of temperature change seen in the mid century. The model does show rising temperatures in the first half of the century, a leveling off mid century, and a strong rise thereafter; but it is obviously not a simple fit to the temperature record – contra your misunderstanding of the "reverse" methods used with models.
(PS. This might yet end up being a case where the models are better than the measurements! It's not all sorted out, but there will shortly be some important revisions to the historical temperature record. Changes in the way different ships measure temperatures give well known systematic errors, which are accounted for in the data already. But some recently published work describing information obtained sorting through the post-war logs of various navies, suggest that there are still some further uncorrected errors. This will have an impact on the mid-century record, but we'll have to wait and see the details.)
As for the observational record: you can get the data direct from RSS here: data description. This is the basis for the graph you wanted me to look at. I've linked to the data description, not the data set itself; anyone wanting to use the data should read this first anyway. The graph at the top of the CA blog is simply the TLT series (lower troposphere) from satellite measurements, using a straight subtraction of two columns in the ascii dataset representing the different hemispheres.
Do note the use of a regression line here; the graph you want me to look at is yet another example showing you the right way to do trends, with linear regression.
For comparison, I have looked at the standard HadCRUT3 data, for the northern and southern hemispheres, just to put some more numbers on the N/H S/H difference... here are the trends, in C/decade, over 1979-present
+0.29 --- TLT from RSS, North, from lat 20 to 82.5
+0.32 --- HadCRUT3, North, above lat 30
+0.22 --- HadCRUT3, Northern Hemisphere, total
+0.06 --- TLT from RSS, South, from lat -20 to -70
+0.07 --- HadCRUT3, South, below lat -30
+0.10 --- HadCRUT3, Southern Hemisphere, total
Hi Duae,
ReplyDeleteI'm enjoying reading the ongoing debate between you and Saturn. I am still a skeptic but it is very informative reading arguments from both sides of the debate. The resepct from each side for the other is also very heartening. Freeman Dyson recently called the debate between the climate skeptics and the mainstream a "dialogue of the deaf" which, in all many cases, is too true. We will never advance the science if that situation continues, so in that respect your forum offers a ray of hope - well done to both you and Saturn.
I'd like to throw a bit of a tangent into the debate. If it's outside the scope of your forum, let me know. However it strikes me that, if we assume for the purposes of this post that something is happening warming-wise, then the methods currently being proposed for dealing with it - limiting carbon emissions - will be hopelessly doomed to fail. The economnic incentives simply aren't there, particularly when it is in each separate nation's economic interest to force others to limit their emissions whilst doing nothing about its own.
It strikes me that, if warming is happening, then iron fertilisation of the oceans would actually promise to have a tangible effect on CO2 levels. It's at least worth some further research. My main reason for thinking this is the Keeling Curve - the yearly oscillations, particularly the northern summer CO2 reduction, show that despite all our industrial and other activity, the biosphere (speifically plants) are capable of sequestering enough CO2 to cause a fall in atmospheric CO2 concentration. If this effect could be replicated by stimulating oceanic phytoplankton growth, which then sequesters (at least a proportion of) the CO2 on a long-term basis (via the biological pump), then CO2 concentrations could actually be reduced (not merely limited as in the presently proposed schemes).
Now I realise a lot of nay-sayers jump up and down about the effect on marine ecosystems, but it strikes me that some of these effects may actually be positive and, in any case, if warming continues, then the effects on the marine biosphere are going to be drastic in any case. Besides, some believe that changing human land use practices and the consequent reduction in dust being blown from land to sea (and stimulating phytoplankton blooms) has actually reduced phytoplankton levels over the past 50 years or so; therefore iron fertilisation would - at least to an extent - simply be redressing the balance.
So my question is: do you know whether or not the pro-warming camp given any serious consideration to iron fertilisation that you are aware of? If not, surely it's worth a look?
Hey Skut;
ReplyDeleteI'd never heard of "Iron fertilization", so I had to look it up. So I'm not speaking with any knowledge.
My own personal inclinations are that we should be really really cautious about deliberately engineering whole-planet environment to suit. Since we are so finely adapted to the prevailing environment, unintended consequences are far more likely to be negative than positive; and unintended consequences are almost inevitable. It's a policy of desperation, I think. And I'm not despairing. I think there are ways to moderate our impact, and which don't involve wrecking the economy. But that's another topic.
On the other hand, you've skewered me neatly; because in fact I don't know much about it; and a rational skepticism should allow that it might be a great idea. So yes, I think it is worth a look.
In my view, regardless of any other approaches we might try, we should still take the foot off the accelerator, and reduce our pressure on the environment. Nudging things back might be worthwhile, and so some study of this would be reasonable; but rushing to deliberately add another new major human impact with an equal but opposite magnitude scares the hell out of me.
The term "pro-warming" is odd, though I guess you mean the people who recognize that warming is real. But surely that includes the people who are proposing and experimenting with iron fertilization? So yes, it gets serious consideration from the "pro-warming camp". The "pro-warming camp", or better "recognize-AGW camp", includes the vast majority of working scientists, so pretty much any group of scientists looking into the subject will include plenty of the "recognize-AGW" camp.
> Well, that sure is the GHCN-ERSST dataset. Thanks. I strongly recommend you go to this link, which I have given previously as well. It will let you make your own plots, look at trends, and also download the numbers.
ReplyDeleteDuae. This is not the data I've seen before. But using your site and depending on the data set you choose and the exact time periods you can get anywhere from 0.02 or -0.01 all the way up to 0.32 rate of increase for this 10 year period between 1999 and 2008. Of course different time periods get even greater variability. Amazingly some of the data sets seem to show almost all the increase in temperature occurring during the later half of the century and some show a more balanced trend. It is very disturbing how little surety we have about temperature data over such recent periods of time and that the proxies are so different.
Even for the period since 1979 and the emergence of satellites there seems to be people who continue to discredit one proxy or another. Scientists who love high sensitivity seem to prefer land site data instead of satellite data. However, when it comes to measuring the troposphere they prefer indirect proxies rather than the equivalent of land data (the balloons). When it comes to the ocean there seems to be a lot of second guessing of the robotic diving probes in the ARGO network we spent so much time and money building and deploying. I thought these were amazing and would settle the debate. Instead when the results came in that the oceans were cooling the HS (high sensitivity) pro-AGW folks were ready with reasons to discount the data again!!! Everywhere we look one group or another is discrediting the data of one source or another. It's amazing actually. The issue of heat islands is still huge and nobody seems to agree if it is accounted for or not. The lack of data and consistency of the data for even the most recent time periods is amazing!
Believe it or not this actually INCREASES my skepticism. The curves variabilities are huge and can occur over shorter or even longer time periods. The amount of the curve varies dramatically on the proxy chosen. This leads me to believe we actually don't know anything and makes me less likely to grip onto the most rapidly changing curves in either direction, predict that will continue for 100 years and say the world is doomed!!!! I understand you believe there is science to back it up but it is very incomplete science. The only way your science "works" is if you get to pick the data sets, the time periods and pick which effects you want to count and which you will ignore or discount. The same could be said of the opposition but this simply tells me no-one knows. That is my position. No one knows. It's not proven. It can't be because nobody can even agree on the data and proxies let alone all the interactions.
When we get to the longer time periods there is debate that seems crazy. We know that Greenland was populated and that it was much warmer than today. It is extremely unlikely that Greenland was 10 degrees warmer for 300 years without the rest of the earth participating in this yet many "scientists" continue to insist the MWP didn't exist around the world EVEN when data is shown that confirms other areas saw warmth and even considering how unlikely the effect would be local. Can anyone name another place on the globe that has experienced much hotter than normal temperatures for hundreds of years while the rest of the planet was cool? Yet HS enthusiasts continue to discredit the MWP because they can't explain it. Yet they can't explain a massively hotter isolated Greenland for 300 years either.
It's quite apparent to me we've had 10 years of no temperature increases. Up until the last 18 months temperatures have remained higher than last century on average but this is simply the nature of an upward slope and the mathematical truism that data near any point on the slope tends to close to that slope. In the last 18 months temperatures have plunged to the point of almost erasing the entire 20th century rise. Sea levels are falling for 2 years now, Kilimanjaros cap is bigger than in 40 years. Did you know that in the US the decade with the most "high temperature records" is not the 1990s but the 1930s! It's not even clear if temperatures are actually warmer than in 1930s. There are written accounts of people traversing the open north pole sea lanes in the 1930s. It is simply not clear at all that the current temperature is particularly high, is continuing to move higher or is going to sustain and this is in spite of the fact that CO2 production is well above anybodies wildest predictions.
You have decided to focus on a trend from 1979. A trend which I say is highly cherry picked since it corresponds too closely to the +side of the PDO and AMO phenomenon. This has created a huge bias in the trends in favor of faster warming. If you remove PDO and AMO somehow from the temperature record of 1979-now then it would be interesting to see what residual CO2 heat remained. I understand how you can get a curve that you can extrapolate 2-3 degrees in the next century if you assume PDO and AMO don't contribute and that we don't get more pauses or temperature declines in the next 100 years. If you remove the El Ninos in the 80s and 90s I think you would find the trend much less and if you were to put in more La Ninas as we would expect with a -PDO you might find the entire 1979-1999 period is flat or down!!!
In any case... I might even have fallen for it for longer had it not been that we've had no temperature increase for 10 years and even more damning the recent plunge in temperatures, the lack of solid data on the land, in the water or troposphere and the constant fighting over the proxies and lack of clarity over temperature even recently let alone over the last 100 or 1000 years. All of this debate makes me believe the theory is not proven and makes HS unlikely.
The mere fact that HS (high sensitivity) proponents are needing to attack the ARGO data and that only recently 2 papers were able to explain partially the lack of tropospheric warming, the denialist attitude towards the recent 10 year (likely 15 or 20) haitus leads me to believe LESS in the theory of HS. Like I've said I am perfectly happy to continue to believe in CO2 being a greenhouse gas that will increase the amount of retained heat but now I'm beginning to realize how that heat can be thrown away in no time at all by an ocean upwelling here or a slightly bigger ozone hole there or movement of energy from one place to another or by a little pollution or by forces we don't understand yet that end little ice ages and cause MWPs. I believe the prudent thing to say is that it is likely the temperature change in the 21st century will be slightly more than the 20th century and 19th centuries and 18th centuries ... probably about 1.2 degrees instead of the 0.7 degrees in those previous centuries (assuming we believe any of the proxies for those times or that you believe in a little ice age.)
Do you believe in the little ice age, Duae? If so, how do you explain getting out of it and the warming over the last 300 years without SUVs?
I simply don't believe the trend from 1979-1998 is sustainable or believable. In fact as you point out it isn't sustained. Even using your proxies the trend in the last 10 years is almost 0. You simply can't get to 2-3 degrees with unexplained 20 year pauses. This will simply be a repeat of the last 3 centuries if that happens and frankly we are in the middle of a 20 year pause most likely which looks suspiciously just like a -PDO period like we've had last century between 1945-1975. I believe the germans that the lack of ocean heat is going to give us a cool 10 more years. If the PDO and AMO cycles persist then it is likely we will have another pause later in the century in another 50 years or so which will give us another 20-30 years of down temperatures and if we get these then the probability of a HS rise seems low. (Let me be a little understated to get the point across gently.)
I also believe that other factors are affecting temperatures that we don't even understand. The idea that the overall trend can somehow be calculated while individual decades can go one way or another is not compelling. There is large uncertainty in the heat of the system and how long it needs to persist that makes such calculations suspect. The amount of heat added by CO2 is miniscule and you depend on H2O and other "feedbacks" to get 2/3 of the heat you estimate for the next century to get high sensitivity. These assumptions are vastly more unproven than even the CO2 forcing. Even if we assume all that it appears that upwelling of cool ocean water or that somehow energy can leak from the system in unknown ways puts large uncertainty on when the extra heat from CO2 will be manifest or if it will ever be manifest.
From a political point of view if you can't show that the temperature is going up 2 or 3 degrees by 2100 then the political argument is lost. If we have 2 or 3 centuries to deal with 2 or 3 degrees then the problem doesn't exist. It is necessary for you to have high sensitivity. It is necessary for you to have this temperature rise be dramatic and occur soon not 300 years from now. It is neccessary for the temperature rise to be damaging to life. It is neccessary that you have some way to mitigate the rise in CO2 that is less painful and costly than simply living with the high temperatures that might or might not happen.
So, to me the case is not proven.
It is so obvious, Duae that we have a theory of CO2 affecting climate but we are far from understanding how it will affect the climate. It seems ridiculous to me for scientists to say they know how this works to such precision. It seems obvious to me that scientists who say that are only saying it because they have a financial reason to say so (grants, financial investments in companies related to AGW) or they have a political position to stake out NOT because the science is proven.
Saturn says: "This is not the data I've seen before."
ReplyDeleteYes, it is. It is the same data you cited in your link to a graph, and it gives the same numbers you have been using to make basic errors in trend estimates.
Saturn says: "Amazingly some of the data sets seem to show almost all the increase in temperature occurring during the later half of the century and some show a more balanced trend. It is very disturbing how little surety we have about temperature data over such recent periods of time and that the proxies are so different."
There's nothing "amazing" about different values in North or South hemispheres, or in different countries. The page lets you look at those. You are also misusing the word "proxy". This data is not proxy; the data on that page is direct measurement, and with good accuracy. You are just being silly now.
The remainder of your comment is mostly a perspective on the basic work of science in sorting through all the different available data on different aspects of climate, in the same way as is done for real world measurements in any area of science.
I think I've explained enough already above about the particular issues of Argos floats, and radiosondes, and satellites, and so on, to give a good idea of how it all works, and I'm content to let my earlier comments stand as given. In my view, Saturn's comment above simply shows he has no experience or understanding of measurement as used throughout science, and certainly no comprehension at all of how a time series of data can show both trends and natural variation at the same time, or how you treat it mathematically. Saturn, on the other hand, apparently thinks I'm just picking and choosing in some way. I'm happy for our two views to stand side by side.
Saturn says: "Do you believe in the little ice age, Duae? If so, how do you explain getting out of it and the warming over the last 300 years without SUVs?"
Available data shows a small drop in global temperatures, and my guess is that solar variation has a part in moving into, and out of, that dip. It lines up roughly with an inferred drop in solar activity obtained independently.
The data also shows different patterns in different parts of the planet, in the past just as in the present. The little ice age period shows some strong drops in the North Atlantic region, but only small drops in the Southern Hemisphere, sometimes not apparent at all above normal variations. Hence I also find persuasive the argument that the NOA (North Atlantic Oscillation) is involved, or other such effects with a strong regional component. Note that these two factors might even be linked. A change in a global input can give a slight direct effect over the whole globe, which in turn can trigger local shifts like the NOA with larger regional differences.
As far as basic physics and thermodynamics goes, the "little ice age" does not have anything like as plain a cause as the much larger global changes now going on right now and which we can measure far more directly.
Thanks for the exchange.
Buried at the bottom of a looong comment thread, tag: http://thinkingforfree.blogspot.com/2008/11/like-you-all-care.html
ReplyDeleteDuae, considering the current extending temperature cold around the world, massive growing ice sheets at the north and south pole, dropping sea levels and the clear association with the negative PDO can you seriously still believe that CO2 is a significant effect on global temperatures?
ReplyDeleteSaturn:
ReplyDeleteYou call this dropping sea levels?
Thank you... I do plan to update it very soon!
ReplyDeleteThis is an old article. Posts that say something complimentary but non-specific, and include some random link, are deemed to be attempts at spam; and deleted without my even looking at the link.
ReplyDeleteStill getting lots of idiotic spam pretending to like this site, but linking to some other page they want to promote. It's dishonest. Stop it.
ReplyDelete
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