Guest post by Dr. J Storrs Hall
A bit over a year ago, in the wake of Climategate, I put up a blog post over at the Foresight Institute which got picked up and run here at WUWT. The essence of the post was that there was lots of natural variation in the ice core record of climate, so that it was reasonable to be skeptical of scientists who claimed that recent CO2 variations were “the only thing that could account for the recent warming trend” (quoting myself).
Apparently that got enough exposure — and was persuasive enough — that over a year later the alarmists still feel the urge to “debunk” it. Most recently, Rob Honeycutt at the “SkepticalScience” alarmist fanboi blog weighed in with this: Crux of a Core, Part 1 – addressing J Storrs Hall. Now the thing about this particular piece that jumped out at me at first was the fact that he associated me with a graph I never used, and he calls me “Mr. Hall” to make me sound less qualified than other sources such as “Dr. Alley” he refers to. It’s Dr. Hall (and yes, I am a scientist, not a nanotech engineer as he claims), a fact that he could have discovered in 3 seconds with Google. That told me about all I needed to know about Honeycutt’s bona fides (in the original Latin sense of acting in good faith).
The only substantive point in the post is that GISP2 (or any specific ice core) is a local as opposed to global temperature record. Is it misrepresentation to use it as a proxy for global climate? Well, the inconvenient truth is that I’m hardly the first person to use ice cores as climate proxies in popular presentations:
… but, on the other hand, it’s actually an interesting question and one worth looking at.
How Ice Cores Record a History of Climate
That’s not my title, it’s from this page at the GISP2 site. Not “a history of local temperature,” — of climate. Here are some quotes from the abstracts of papers by GISP2 authors:
“Ice cores provide high-resolution, multi-parameter records of changes in climate and environmental conditions spanning two or more full glacial- interglacial cycles. …”
“Polar ice contains a unique record of past climate variations; …”
“One of the most dramatic climate events observed in marine and ice core records is the Younger Dryas (YD), … High resolution, continuous glaciochemical records, newly retrieved from central Greenland, record the chemical composition of the Arctic atmosphere at this time. This record shows that both onset and termination of the YD occurred within 10-20 years …”
“The Greenland Ice Sheet Project 2 (GISP2) core can enhance our understanding of the relationship between parameters measured in the ice in central Greenland and variability in the ocean, atmosphere, and cryosphere of the North Atlantic Ocean and adjacent land masses. …”
“High-resolution, continuous multivariate chemical records from a central Greenland ice core provide a sensitive measure of climate change…”
“The accumulation record from the GISP2 core as an indicator of climate change throughout the Holocene” (paper title)
So, sure, a single ice core is not a global average temperature record; but it is quite a bit more than one thermometer. It’s just mud-slinging to claim that using it for a climate proxy is “misinformation”.
… especially when I didn’t just use one ice core in my post but two, and the other one was from Antarctica. One way to cut past the verbiage is simply to look at a comparison of the Greenland and Antarctic data and see how well they correlate:
(This is GISP2 in green, NGRIP, another Greenland core, in cyan, and the Vostok Antarctic core in blue. The Vostok has been scaled and shifted for a best match with the others; the temperature in Antarctica is colder, with smaller variations, than in Greenland. Furthermore, there are some time-scaling issues — note the temporal divergence of the two Greenland records before about 40 kya. It’s possible that NH/SH actually match better than this plot indicates. Look here for data.)
Nowhere near a perfect match, but it’s pretty clear that these are all from the same planet. Even Vostok shows the Younger Dryas, which is generally believed to be a mostly northern-hemisphere event. The NH has more variability in ice ages, notably the Dansgaard-Oeschger events, but the SH more, on a relative scale, in the Holocene.
The GISP2 people also compared their core’s record with Antarctic ones; on this page they say that it “shows close correlation between GISP2 and Vostok in the delta 18O of air in these ice cores.” (That’s a key temperature proxy.) On this page they say “Holocene climate is characterized by rapid climate change events and considerable complexity. GISP2 Holocene ¶18O (proxy for temperature) (Grootes, et al., 1993) and EOF1 (composite measure of major chemistry representing atmospheric circulation) show parallel behavior for the Early Holocene but not for the Late Holocene (O’Brien, et al., 1995).”
Note that bit about “rapid climate change events.” In the words of Jeffrey Masters here, “The historical records shows us that abrupt climate change is not only possible–it is the normal state of affairs. The present warm, stable climate is a rare anomaly.” (And he’s talking specifically about the lessons of GISP2 — although alas he takes home the wrong lesson from it.) See also this recent post here by Don Easterbrook.
Does GISP2 — or any other paleoclimate record — show us that climate change isn’t happening? No, of course not. It shows us that climate change always happens. The 20th-century warming was hardly unprecedented, and doesn’t call for unusual explanations.
Joel says: quoting me-
‘and not, as the modellers thought for 30 years, due to human emissions of sulphur – but they have not publicised that new science’
I can give you three good references from Science in 2005 that scuppered the IPCC modellers consensus that ‘global dimming’ was due to anthropogenic sulphur aerosols – they are all in my book, with a chapter on how important this issue remains:
Pinker R.T., B. Zhang and E.G. Dutton (2005) Do satellites detect trends in surface solar radiation? Science 308 p850-854
Wielicki B.A. et al., (2005) Changes in earth’s albedo measured by satellite Science 308 , 825
Wild M. et al., (2005) From dimming to brightening: decadal changes in solar radiation at the Earth’s surface Science 308, 847-850
If you read these works you will readily see that ‘global dimming’ was a localised mostly land-based phenomenon (perhaps 10% of the globe) – whereas the drop in global temperatures from 1945-1975 was evident across all oceans and both hemispheres including large unpolluted areas, and was a combination of cloud and aerosol forcings which shifted to ‘brightening’ around 1980 – well before the suplhur reduction protocols had made much effect in those limited zones.
This is entirely in line with ou understanding of ocean cycles such as the PDO.
I wish I could give you a reference from IPCC 9 chapters of Working Groups – but in the course of my research for the book, I came across a single sentence that admitted the previous understanding of the global trough from about 1945-1980 was wrongly ascribed to human agency. It was pretty-well buried. I have searched for it a few times in Chapter 2 on radiative forcing and Chapter 9 on attribution studies but never found it – those chapters do refere to Wild’s work, but obfuscate the implications. I don’t think anyone sufficiently informed would now claim the trough was due to anthropogenic sulphur, any more than the modellers would draw attention to the fact that they hindcast this trough as anthropogenic and validation that their models were reliable! It is a big issue.
I asked Gerry Meehle at NCAR this question – he was still, in Februrary 2010, under the impression the trough was accurately modelled (I guess different groups don’t have much time to talk to each other) and had ‘no idea what I was talking about’.
You can see, just as you would have had no idea – and I don’t expect you to until you read those three papers, that the models have made a huge error – so do many scientists in the field, because they don’t actually spend much time checking each others work, nor looking across disciplinary boundaries.
You then quote me on RFs:
‘ The writing on the wall says that the RFs have been way over-estimated. That means CO2 does not have the power the earlier modellers assumed – by the time it reaches 200 ppmv, its greenhouse work is all but done. ‘
The latter point is easily verified by visiting any site with MODTRANS output – the RF for carbon dioxide rushes up to 255 watts/square metre (at the tropopause) by the time concentrations reach 200ppmv (about where they are during the ice-ages). The next 100ppmv raises that by 2.5 watts. And the pre-industrial level of 280 to today at 385 raises it another watt. Doubling from pre-industrial to 560 ppmv gives a total of about 3.5 watts/square metre – or about 3% of the global average downward flux at the tropopause (the system is modelled by using conceptual equilibrium – which the system is never in – but that’s another issue!). A good scientific question is ‘what is the natural variability’….and what kind of statistical tests would identify such a signal….but again, another issue!
So – that is the RF calculation. How reliable is it? After all, it takes a massive computation to deal with all atmospheric layers up to the tropopause at 10km, all the different gases and their properties to absorb and reflect or re-emit radiation, and their interactions with each other – including water vapour and clouds and natural aerosols. Well, I tried hard to find good references to this original piece of science and the paper trail led to an USAF unit that sells the MODTRANS programme for $300 – and it seemed a lot of labs relied upon this. However, I have recently asked Keith Shine at Reading for guidance and he has just sent me a long list of references assuring me that this part of the calculation is both well understood and more readily available in the science literature – but I have yet to find time to read all that stuff.
Until a few days ago, i was quite ready to accept that RF was basic physics and not controversial, because there is enough uncertainty in how it is used to translate the watts/square metre at 10km downward flux into Temperature at the surface. Shine himself has a useful paper on this:
GEOPHYSICAL RESEARCH LETTERS, VOL. 30, NO. 20, 2047, doi:10.1029/2003GL018141, 2003
An alternative to radiative forcing for estimating the relative
importance of climate change mechanisms
Keith P. Shine, Jolene Cook, Eleanor J. Highwood, and Manoj M. Joshi
Department of Meteorology, The University of Reading, Reading, UK
In this paper he shows that the factor lambda in the equation
T = lambda. RF
can vary between 0.4 and 0.8 – the latter being the IPCC’s preferred value.
I think you can empirically find 0.4 from the global data rather than models – but again – long story!
So – if you apply 0.8 to 3.5………as at the IPCC, you get 2.8 C, and if you apply 0.4 you get 1.4 C and not such a scary climate story.
BUT I am no longer assured about the reliability of RF calculations. And I have WUWT to thank (at least I think it was, I don’t visit many blogs) for the extra head-banging, in drawing attention to the work of Hermann Harde
Helmut-Schmidt-Universität Hamburg, Germany (harde@hsu-hh.de)
and I give you this abstract in full, because if he is right (I have yet to get the paper and stretch my simple ecologist’s brain), then it is probably the most important climate science paper in recent years:
‘Based on the actual HITRAN’2008 database [1] detailed spectroscopic studies on the absorbance of the greenhouse gases water, carbon dioxide and methane in the atmosphere are presented. The objective of these investigations was to examine and to quantify with these newly available data the influence of these gases on our climate.
The line-by-line calculations for sun light from 0.1 – 8 m (short wavelength radiation) as well as those for the emitted earth radiation from 3 – 60 m (long wavelength radiation) show, that due to the strong overlap of the CO2 and CH4 spectra with the water vapour lines the influence of these gases is significantly reducing with increasing water vapour pressure, and that with increasing CO2-concentration well noticeable saturation effects are observed limiting substantially the impact of CO2 on the warm-up of the atmosphere.
For the water vapour, which in its concentration is considerably varying with the altitude above ground as well as with the climate zone, separate distributions for the tropes, the moderate zones and the polar regions are presented.
They are based on actual GPS-measurements of the water content in these zones [2] and are applied for calculating the absorbance in the respective regions. The vertical variation in humidity and temperature, in the partial gas pressures and the total pressure is considered for each zone separately by computing individual absorption spectra for up to 228 atmospheric layers from ground level up to 86 km height.
The propagation length of the sun light in these layers, which depends on the angle of incidence to the atmosphere and therefore on the geographic latitude, is included by considering the earth as a truncated icosahedron (bucky ball) consisting of 32 surfaces with well defined angles to the incoming radiation and assigning each of the areas to one of the three climate zones.
To identify the influence of the absorbing gases on the climate and particularly the effect of an increasing CO2- concentration on the warming of the earth, a two-layer climate model was developed, which describes the atmosphere and the ground as two layers acting simultaneously as absorbers and Planck radiators. Also heat transfer by convection between these layers and horizontally by winds or oceanic currents between the climate zones is considered.
At equilibrium each, the atmosphere as well as the ground, delivers as much power as it sucks up from the sun and the neighbouring layer or climate zone.With this model for each climate zone the temperature progression of the earth and the atmosphere is calculated as a function of the CO2-concentration and several other parameters like ozone and cloud absorption, short- and long-wavelength scattering at clouds as well as the reflection at the earth’s surface.
The simulations for the terrestrial and atmospheric warm-up show well attenuating and saturating progressions with increasing CO2-concentration, mainly caused by the strongly saturating absorption of the intensive CO2 bands and the interference with water lines. The climate sensitivity CS as a measure for the temperature increase found, when the actual CO2-concentration is doubled, assumesCS = 0.41°C for the tropical zone, CS = 0.40°C for the moderate zones and CS = 0.92°C for the polar zones. The weighted average over all regions as the global climate sensitivity is found to be CS = 0.45°C with an estimated uncertainty of 30%, which mostly results from the lack of more precise data for the convection between the ground and atmosphere as well as the atmospheric backscattering.
The values for the global climate sensitivity published by the IPCC [3] cover a range from 2.1°C – 4.4°C with an average value of 3.2°C, which is seven times larger than that predicted here.
1. L.S. Rothman et al., The HITRAN 2008 molecular spectroscopic database, J. Quant. Spectrosc. Radiat. Transfer 110, 533–572 (2009)
2. S. Vey: Bestimmung und Analyse des atmosphärischen Wasserdampfgehaltes aus globalen GPSBeobachtungen einer Dekade mit besonderem Blick auf die Antarktis, Technische Universität Dresden, Diss., 2007
3. D.A. Randall et al., Climate Models and Their Evaluation. In: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change [S. Solomon et al. (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.
You will note that he gives the value in T degrees C…for the doubling, as 0.45. This is actually quite close to Lindzen’s figures, I believe, though he would come via a different route.
The fact that neither Lindzen nor Spencer have questioned either MODTRANS or HIGHTRANS does not mean a lot – I imagine it is a big task to check it all line-for-line and when there is so much more uncertainty in the translation of Lambda, why bother?
When I do read the paper, it may well be that the main issue IS the translation to T at the surface and not the RF at the tropopause – but they are part and parcel of the RF approach and it is shot through with uncertainty. This is supposedly the ‘settled’ and very basic science of AGW. There is actually very little wrong with the science itself – you will find plenty of acknowledgment of uncertainties like these, as well as publications which downplay them – such as the Summary Reports of the IPCC Working Group.
PS:
forgot to include the reference to Harde:
Geophysical Research Abstracts
Vol. 13, EGU2011-4505-1, 2011
EGU General Assembly 2011
© Author(s) 2011
How much CO2 really contributes to global warming? Spectroscopic
studies and modelling of the influence of H2O, CO2 and CH4 on our
climate
Smokey says:
It is not a matter of mind reading; it is just a matter of reading what you write.
Your statements are completely meaningless. A young earth creationist can say, “If and when there is convincing evidence that the Earth is more than 6000 years old, I will change my mind.” And, like you, he would then proceed to pronounce himself unconvinced by the evidence, set himself up as judge-and jury, and completely ignore the fact that just about every major scientific body on the planet disagrees with him.
I will state the truth clearly: You will never be convinced of AGW, no-how, no-way, and anybody who believes otherwise is naive in the extreme. Because you are not operating on the basis of letting the evidence lead you. You are operating on the basis of desperately cobbling together whatever evidence (however poor) you can find to convince yourself of what you are ideologically set on believing.
Your statement is vacuous and utterly devoid of meaning and is really just a way to pretend to be open-minded when you are anything but.
Well, I suppose it is the egalitarian nature of the internet that allows someone who has no scientific credentials that one can ascertain whatsoever to pronounce himself the arbiter of the scientific method, and who and who does not understand it, proclaiming how some of the world’s top scientists (as well as some middling scientists like myself) do not understand it as well as he does. I must say, your modesty becomes you!
Thank you Joel for taking the time to post that and previous posts.
It would be nice if your words were given some good faith serious consideration.
commieBob March 7, 2011 at 6:42 am says: “The warmistas claims are based on proving: “1 – Modern warming is unprecedented
2 – We are approaching a tipping point caused by positive feedback
3 – The climate is non-linear and crossing the tipping point will cause a sudden and irreversible warming by about six degrees.”
~ ~ ~ ~ ~ ~ ~
First off, can you define “Warmistas” I don’t understand what you mean?
~ ~ ~ ~ ~ ~ ~
Seems to me you got some straw men there. Shouldn’t the first order of business be getting a clearer picture of what is going on within our atmosphere… and how that relates to weather patterns, etc. which over the long term is categorized as climate?
Your above three points mischaracterize the basic understanding we must achieve.
I would suggest the following list of questions are more appropriate:
1 – Does CO2 (along with other GHGs) influence our atmosphere? 1a – Is there physical evidence to suggest CO2 has thermo properties… have those properties been quantified?
1b – Is there evidence that atmospheric CO2 (& GHG) levels are increasing due to human activity?
1c – Is there evidence to suggest real-time effects of CO2’s atmospheric thermo properties is being witnessed on the planet?
2 – Beyond that: Are our oceans drivers of warming/cooling or do they merely circulate warmth according to the atmosphere’s thermo condition and their interface?
3 – Is the sun, {or Earth’s orbital variations}, acting in a manner that is meaningfully increasing or decreasing current insolation (incoming sun’s energy)?
4 – Which temperature reconstructions can we trust?
5 – Where is the IPCC claiming tipping points, or imminent catastrophe?
Joes Shore says:
“It is not a matter of mind reading; it is just a matter of reading what you write.”
Because your mind is closed, you do not comprehend what I write. I don’t need to ‘cobble together’ any evidence, for I am a scientific skeptic. Climate alarmists like Joel who push the debunked CO2=CAGW conjecture are the ones with the onus of producing evidence: Their failure rate so far = 100%. There is no evidence of planetary damage due to CO2. None. The conjecture is being falsified by the ultimate authority: planet Earth.
“I will state the truth clearly…”
Joel has a corner on the truth! In fact, it’s still just a lot of chin music, with zero evidence of any global harm from CO2 being presented. Oh, and hey, I like Joel’s new sycophant. An entourage of one!☺
Peter Taylor –
Thanks for the references and commentary. I have to admit that I remain pretty skeptical though. For one thing, I don’t really see where those Science papers that you referenced lead to the conclusions that you seem to have drawn from them. The conclusions certainly don’t seem to be in the papers themselves, nor are they, as you note in the IPCC review of those papers or in the minds of people knowledgeable in the field like Meehl. You think it has to do with people not looking across disciplinary boundaries and such, but there are also more parsimonious explanations, such as the conclusions that you have reached not being warranted.
As for the RF issue, it sounds like you are putting all your eggs into the basket of that Hermann Harde paper. An argument that relies on one very new paper that we have only seen the abstract to and which claims the previous work is all wrong should be treated with a great degree of caution and skepticism even if it appeared in an outstanding peer-reviewed journal by a respected author in the field. In this case, you have a submitted paper to a conference that I do not believe is peer-reviewed at all by somebody who is apparently pretty much unknown in the field making these strong claims. That is a pretty dangerous basket to put your eggs in!
Time will tell…but I will be willing to make a friendly bet that in a few years time, Harde’s paper won’t be held in much higher esteem than that of Gerlich and Tscheuschner.
P.S. – This is somewhat beside the point. But, I am confused by your statement:
That 255 W/m^2 number sounds awful high to me given that the total absorbed solar radiation is only 240 W/m^2…and the total amount of back-radiation (from the higher amount emitted by the earth’s surface) is still only ~333 W/m^2, of which the majority would presumably be due to water vapor and clouds. What am I missing here?
Joel Shore, thanks for your comments – I appreciate you following up the papers in Science.
Ny reading of them and what the authors say very clearly is that ‘global dimming’ ended around 1980 and the brightening was not confined to the polluted northern hemisphere – moreover the atmosphere cleared well before the sulphur pollution controls rook effect (I was heavily involved in the acid rain campaigns in Europe at the time and the protocols that would restrict emissions did not kick in until the late 1980s – moreover, global sulphur emissions levelled off, with those in the West counterbalanced by those in the East). In any case, all such emissions are very low level compared to the stratospheric injections from volcanoes that are required to depress global temperatures. The brightening was observed even in Samoa.
I will eventually hunt down the IPCC para that confirmed this in 2007 (if you want to send me an email, I will send it to you when I find it! (peter.taylor(at)ethos-uk.com ).
Regarding the RFs. It is something I am currently reviewing and a subject i did not tackle in the research for ‘Chill’ – I assumed it was basic physics. You are quite right, I may be laying too much emphasis on Harde’s work, but my main point is that there is significant (to me) discord in the scientific literature on what is supposed to be basic science. On reflection, Harde seems less to be challenging the RF values as computed in watts/square metre at the tropopause (a convention for defining the equilibrium point and inputs of forcing into models) – he may do, I will wait to see the paper – but clearly does challenge the factor that translates this value to a change in temperature at the surface. Given the complexity of this area – clouds and aerosols, and IPCC’s own admission of very poorly constrained science for the models, there is ample scope for disagreement and uncertainty. As I noted, IPCC in 2007 preferred a factor of 0.8 (this would be applied, for example to the eventual doubling of the RF by 2050 or thereabouts of 3.5 watts/square metre). There are already sufficient doubts – summarised by Shine (GEOPHYSICAL RESEARCH LETTERS, VOL. 30, NO. 20, 2047, doi:10.1029/2003GL018141, 2003) who prefers a factor of 0.44. I do not know what the error margins are for the original RF at the tropopause calculations – but I am still reading the literature (please note, I am an ecologist by training – and thus have a non-specialist knowledge across several disciplines and this takes time!).
It appears that Modtrans – which was a private sector product, had been replaced with Hitrans, which has an international team from reputable institutions at work on it and is continually revised and scrutinised – this is what Harde worked with. There is, I assume, less uncertainty here than in the lambda factor noted above. Keith Shine has been kind enough with his to point me to the literature. I should add that he is a leading authority in the field and part of IPCC working groups on these issues.
I will check to see if I have understood things correctly on the values I quoted – my understanding is that at the tropopause the incoming short wave radiation from the Sun amounts to an average across the globe, taking account of the incident angle, of about 340 watts/square metre (it is about 1365 at the equator). That radiation is balanced by outgoing long wave radiation. (If I understand it, some or all models use the altitudinal point where the atmospheric temperature is -19 C, the temperature that fits the outgoing radiation profile, as the ‘equilibrium’ point for the calculations).
That 340 watts figure is then primarily reduced by cloud – by about 25%, in terms of the net flux of radiation to the surface – which gives you a gross figure of 255 watts. What I do note is that a small percentage shift in cloud cover can equal the whole of the accummulated carbon dioxide forcing – and we know cloud cover does vary of decadal time scales and is the main candidate for warming and cooling cycles in ocean basins. The whole of the MWP/LIA variability may be down to clouds (irrespective of the mechanism – and you don’t have to invoke Svensmark’s effects, though they probably do contribute).
I can’t account for the high modtrans figure – I have only seen one graph of the log relationship expressed in watts and it was not fully referenced – finding one is like looking for hens’ teeth – so if anyone else has access (to modern Hightrans equivalent) – please contibute your knowledge! But every graph I have seen of the computed translation to temperatures at the surface, shows that CO2 concentrations have a very large effect in the first 50 ppmv and very small effects beyond 200 ppmv – and the upper slopes of that graph will be subject to uncertainty….between 200 and 500 ppmv they are almost linear.
Calculating the ‘sensitivity’ is not straightforward – there are empirical ways looking at ice-cores, but the CO2 profiles do not match the temperature profiles in timing – with very large movements of temperature upwards before any CO2 upward trend, and drops when CO2 remains high, and even rises in T while CO2 is falling. I have seen estimates in the literature of 7ppmv per degree….which would place 100% of the warming from 180 to 280 ppmv as caused by CO2 and its assumed feedbacks – I don’t think the data supports this.
My overall impression – is that sensitivity to CO2 is much lower than IPCC models assume – even lower than Shine’s figure would suggest. Harde’s work looks to bring it down further…with a factor lying perhaps between 0.1 and 0.2 for lambda and hence about 0.5 C for the doubling. If the ‘truth’ lies somewhere between Harde and Shine, at say, o.3 then we are looking at only 1 C change by 2050 (assuming economic structures maintain growth of material consumption despite diminishing cheap energy supplies).
My main point has always been – the peer-reviewed literature is the best source of knowing how reliable the models are – you cannot rely upon the IPCC who long ago made a prior commitment to higher values – it is too hard for them to backtrack and say the problem might not exist!