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Ken Lambert at 23:43 PM on 7 July 2010Astronomical cycles
Chris #136, kdkd various, JMurphy I deal with highly non-linear larde deflection FEA analyses every day. Many engineering relationships are non-linear, much of nature is non-linear - so what is this big deal about statistical linearity? I think the point is made about the large uncertainties in OHC and lesser but definite uncertainties in SLR particularly in the proportions of ice melt and steric rise. As for other explanations of Trenberth's missing heat, one that comes to mind is that it was never there in the first place. And for Chris - mate - you led with your chin so don't complain when you suffer a 'correction' -
Ken Lambert at 23:31 PM on 7 July 2010Astronomical cycles
Peter Hogarth #137 Reasonable comment Peter. One of the key points I highlighted from this excellent blog and Dr Trenberth's analyses, is that TOA energy flux imbalance must show up in OHC somewhere, sometime due to two factors - the relatively tiny storage capacity of the atmosphere, and very small absorption of heat in melting ice in global terms compared with the integral of the purported TOA imbalance. Really accurate OHC measurement is the key to measuring the extent of global warming. -
JMurphy at 23:12 PM on 7 July 2010Tai Chi Temperature Reconstructions
On a more tangential note, it's good to see that yet another enquiry (The Independent Climate Change E-mails Review under Muir Russell) has exonerated the scientists and the science. I'm sure thingadonta will join us in congratulating Phil Jones and the rest of the team. Shame the so-called skeptics have already decided this would be a whitewash - like every other enquiry they don't like the result of... -
Peter Hogarth at 23:06 PM on 7 July 2010Tai Chi Temperature Reconstructions
thingadonta at 20:28 PM on 7 July, 2010 Metamorphism over past 2000 years in sediment cores? please, I have some hands on experience and knowledge of Geology and GeoPhysics, and so do many people analysing core samples. "I am not a tree ring specialist", agreed, this is clear, (neither am I), but you could improve your understanding by reading the references, finding more, or asking intelligent questions rather than framing whimsical questions which demonstrate your own bias. -
plevy at 23:01 PM on 7 July 2010Tai Chi Temperature Reconstructions
And another thing, thingadonta... do you really mean "Tree ring data is handed over to mathamaticians", or is it really handed over to statisticians? There's a big difference. Also, your remark about subprime mortgages is, as far as I can see, completely irrelevant. How many practising academics (mathematicians or otherwise) were involved in assessing subprime mortgages? -
chris at 22:10 PM on 7 July 2010Tai Chi Temperature Reconstructions
thingadonta at 20:28 PM on 7 July, 2010 thingadonta, your post says essentially nothing about this subject. Note that "radioactive decay" certainly doesn't "reset with metamorphism". If one uses a radioactive dating technique like potassium-argon dating where analysis requires measurement of trapped gas (e.g. argon) in rocks, then the dating "clock" is reset upon metamorphosis (the gas is released when the rock melts). But that's of little relevance to paleoproxy analysis covering the past 2 millenia. In that case radiocarbon decay is likely to be used. Metamorphosis in the geological sense isn't relevant to dating on the millenial timescale Metamorphosis in the sense of conversion of carbon to graphite or charcoal, doesn't perturb the dating analysis. If one considers longer timescales (e.g. uranium-thorium dating of speleothems/stalagmites or coral), the question of metamorphosis is likely to be of little relevance since the intactness of the coral or stalagmite can be assessed by inspection. The same applies to cores. Otherwise your list is simply a set of "what if's" that the scientists engaged in this research will certainly have considered. Indeed, one could take your approach to any topic. For example I might display some skepticism over your suggestion that you are going to drive to the seaside this weekend: Here are some suggested problems with your trip from an interested onlooker, just off the top of my head. Are any of the following true I wonder? - Your car might be out of petrol. For example even though you filled it up yesterday, someone might have siphoned your tank during the night. - Someone driving carelessly might have ripped off one of your wing mirrors. - You might have a flat tyre and your spare may be bust. - You may be unable to find the way. Even 'though you think you know the route there have been some changes in the roads, and there may be some unexpected diversions. - You have to go over a couple of bridges on the way to the seaside and one of these might be closed, or may even have fallen down. etc. etc. ad nauseum And no doubt you think we should make an effort to find imaginary flaws in the findings of heart surgeons, or scientists trying to understand the genetic basis of Huntington's disease, or nanotechnologists, or cancer researchers etc. because: Researchers who study these things are a small nit[*] group who are almost exclusively looking for a story. (Research bias) small "nits" thingadonta? Were you thinking of head lice.....? -
JMurphy at 22:06 PM on 7 July 2010Tai Chi Temperature Reconstructions
thingadonta wrote : I know from my field, that radiaoctive decay resets with metamorphism, and there are also problems with data collection and verification. It gets worse in disturbed terrains, and in older rocks. And yet most rocks are dateable, aren't they ? Or are there areas of the world that cannot be dated because of the problems you mention ? I'm sure Creationists could come up with lots of arguments about problems in dating rocks but surely you would be able to show them that, in the main, dating techniques and interpretation are correct ? -
skywatcher at 21:58 PM on 7 July 2010Is Willis Wrong at WUWT? or Sensitivity and Sensibility I
It's enough to make your brain melt in despair! But always good to push back against the bad science. I can't work out the figures, but it looks a bit to me like the values are merely reporting the relative proporions of land and sea at the different latitude bands - ie most in the NH mid-latitudes, least in the SH mid-lats. But of course you'd expect that for differential rates of heating/cooling over an annual cycle! -
thingadonta at 20:28 PM on 7 July 2010Tai Chi Temperature Reconstructions
"I have not seen many smeared tree rings or stalagmites or sea bed cores." I know from my field, that radiaoctive decay resets with metamorphism, and there are also problems with data collection and verification. It gets worse in disturbed terrains, and in older rocks. I am not a tree ring specialist, but sometimes an outsider might spot a few issues that insiders might take for granted. Here are some suggested problems with tree rings and T reconstuctions from an amatuer in another field (geology), just off the top of my head. Are any of the following true I wonder? -There isn't always a one-to-one correlation with tree ring width, colour, mineralogy etc; and temperature. (Big red flag number one). -Trees are selected which are by nature robust over long periods of time to begin with (so they can show very long time periods), and are therefore not sensitive to small-period fluctuations. This is a sample selection problem. That is, if a tree is highly sensitive to small T changes, it dies and produces no tree rings, and therefore will not show up in the data-result is you get smoothing of data the futher you go back in time, and the more robust trees become over-represented. -Volcanic events, fires, bugs, human settlement, slash and burn, and changes within the tree itself, alter the shape and nature of the rings with time. Ie. Earlier rings get metamorphosed with time, both by internal tree factors, and external factors. Again, age makes it worse. -Researchers who study tree rings are a small nit group who are almost exclusively looking for a story. (Research bias) -Access to tree ring data, (as is usual for academics still living in the dark ages), is not available. Requests are ignored. (Research bias). -Tree ring data is handed over to mathamaticians who have no understanding of these sort of issues and massage the data, thinking its all the same anyway, and will average out, just like sub prime mortgages. - -
John Russell at 19:43 PM on 7 July 2010Is Willis Wrong at WUWT? or Sensitivity and Sensibility I
To me, the following very innocent comment cut and pasted from 'Larry L' on the WUWT thread is very revealing of the feeling within the denier blogosphere of 'not wanting to accept'. It sums up a feeling of helplessness really exquisitely. I guess Larry is a typical example of the vast majority of denial followers. There's no equivalent amongst -- as they like to call us -- 'the warmists'. /"Sometimes this sort of back of the envelope analysis is more powerful than sophisticated modeling because it is based on the real physics even if we do not understand all the physics we know the results are real."/ -
Peter Hogarth at 18:58 PM on 7 July 2010Tai Chi Temperature Reconstructions
johnd at 08:10 AM on 7 July, 2010 I believe proxies are calibrated for offset and scale, but I don't think they are de-trended. I agree tree rings are relevant, but I disagree with your summary “The Briffa tree ring reconstruction began to diverge” etc. The divergence "problem" has been known for a while. It is important to resolve it. Buntgen, Esper, and other researchers have responded to this head on with new work, new evidence and more comprehensive data, which is the way things should work. Their new evidence moves on from the divergence problem, and addresses the issues leading to it arising in the first place. Please read the references below. If your current position is as you state, then it is probably time to modify it in the light of new or emerging evidence. Perhaps you may even be surprised. Science moves on. On recent work on proxy tree ring data showing no divergence Buntgen 2008. On new research into altitude related growth patterns, Moser 2009. On the divergence problem specifically Esper 2009 and for an updated analysis which specifically addresses contentious Siberian tree ring data, Esper 2010. -
skywatcher at 18:58 PM on 7 July 2010Tai Chi Temperature Reconstructions
johnd, I can only repeat what KR has said - you are utterly incorrect if you think I was saying the same thing as you. The samples are independent - think lots of different urine samples, to use your analogy. Processed by different methodologies, depending on the type of urine sample (OK I have to stretch it here, wee is just wee), but in a standard manner for the relevant methodology. This leaves bags of room for all sorts of results. Wildly varying results with no consistent conclusion - definitely not the case here. How about a consistent conclusion that bears no resemblance to either the instrumental record and previous palaeo-reconstructions? No again. How about a record that is relatively consistent, and bears a resemblence to such records, as Peter has neatly shown. There is no pre-determined outcome. As Donald Lewis says, if you doubt the original data (the individual wee samples), then go and get your own samples and show why the original samples are pre-determined to give a result. If the methodology pre-determined the result, there would not be curves like #2 (Lake Toskaljavri) or #17 (Lake Flarken), which don't show the bent 'hockey stick' of Peter Hogarth's analysis. -
MarkR at 18:03 PM on 7 July 2010Is Willis Wrong at WUWT? or Sensitivity and Sensibility I
RE #5: I had some spare time and through checking this I found some papers that I thought were pretty interesting: I plan to include them in the next part. I've been internet chatting with people who wave this around like a banner. I know they'll never accept any physics or evidence that goes against what they believe, but other laypeople who'd otherwise fall for Willis' sleight of hand might do so. I hope this would help them. It's also a cautionary tale for any estimates of climate sensitivity from regional methods: including Lindzen's estimates of climate sensitivity from top of atmosphere tropical radiation. -
John Brookes at 18:01 PM on 7 July 2010Is Willis Wrong at WUWT? or Sensitivity and Sensibility I
I have an idea that John Cook might like to follow up in relation to silly arguments like Willis' above. Can we establish a list of things which both sides of the debate agree on? Because I think the more sensible sceptics will agree with quite a lot, and if they do, then their less knowledgable(how do you spell it?) followers might stop coming up with stupid arguments. We could start with very simple things, like what the earths temperature would be if there was no water or greenhouse gases in the atmosphere. -
Donald Lewis at 17:05 PM on 7 July 2010Kung-fu Climate
Just read your piece, and none of the comments. Bravo! Very nice. -
Donald Lewis at 16:55 PM on 7 July 2010Tai Chi Temperature Reconstructions
@Johnd and others Peter has provided an independent and idiosyncratic analysis of published data. That is a meaningful and a helpful contribution to understanding the data. If your complaint is with the data, go get some of your own that meets your standards. Then present your analysis of it. Perhaps then those results will "surprise" you or not. I doubt Peter was aiming to surprise anybody, I suspect he was trying to understand the data in his own terms. That is a human virtue, I think, and I am glad he shared his experience. -
Philippe Chantreau at 16:36 PM on 7 July 2010Is Willis Wrong at WUWT? or Sensitivity and Sensibility I
Fair enough Rob, but let's not call this science, because it is as far from it as can be. It falls in the "so bad it's not even wrong" category. -
Donald Lewis at 16:26 PM on 7 July 2010Tai Chi Temperature Reconstructions
Nice romp Peter, thanks. -
SNRatio at 16:22 PM on 7 July 2010Is Willis Wrong at WUWT? or Sensitivity and Sensibility I
Thanks for the link, philipm! For the record, I paste the basic "definition" here: "The Gish Gallop is an informal name for a rhetorical technique in debates that involves drowning the opponent in half-truths, lies, straw men, and bullshit to such a degree that the opponent cannot possibly answer every falsehood that has been raised, usually resulting in many involuntary twitches in frustration as the opponent struggles to decide where to start. It is named after creationism activist and professional debater Duane Gish." It's sad. but ignoring such bullshit as Willis E's last groundbreaking research results altogether can only make things worse. So I think we should rather take this more as entertainment. And we should be aware of the Gish Gallop phenomenon, and try to develop simple and efficient counter rhetorics against the denialists. As for the sensitivity issue, I think it is wise to be very careful and rather use very conservative estimates. The full sensitivity can only be assessed after several hundred years, when the system has reached a new equilibrium, and in the meantime, the people who shout "hey, the observed sensitivity is less than you said" will be kind of right. In the transition, quasi-periodic phenomena may also crop up and confuse a lot. -
philipm at 16:08 PM on 7 July 2010Is Willis Wrong at WUWT? or Sensitivity and Sensibility I
In a moment of weakness I went and read all the comments. Crazy stuff. Apparently climate sensitivity and the propensity for the earth to be in 1 of 2 states, glacial and interglacial, are totally orthogonal concepts. -
philipm at 15:16 PM on 7 July 2010Is Willis Wrong at WUWT? or Sensitivity and Sensibility I
For those who want a better handle on the real science, RealClimate has recently posted a nice article aimed at the scientifically literate non-expert. Meanwhile Gish is galloping once again... As you say, Mark, a simple thought experiment suffices to show this one's ridiculous. Why can't regular readers of WUWTF (spelling intentional) see through this for themselves? I mean, really: if there is a serious case that the science is flawed (and I've been looking hard for a few years in the faint hope that things aren't as bad as I fear they are), why do they entertain this sort of drivel? -
Albatross at 13:59 PM on 7 July 2010Is Willis Wrong at WUWT? or Sensitivity and Sensibility I
I am honestly at a loss of words! -
Rob Honeycutt at 12:38 PM on 7 July 2010Is Willis Wrong at WUWT? or Sensitivity and Sensibility I
Philippe... As awful as it is, it's important for science to address things like this. It's worse to ignore it and think it will go away. Every time bad science like this comes up in the media it's important to address it so that at least some people will understand that it IS bad science. Even if a post like this only has the effect of altering a few people's opinion on climate science, those few people could, in the long run, be extremely important. You never know. -
robert way at 12:31 PM on 7 July 2010Tai Chi Temperature Reconstructions
I'm kinda opening up this question for anyone here. How does one calculate anomalies if considering multiple records which do NOT ALL or mostly cover the anomaly period? Kinda working on something and having a trouble figuring it out myself -
Philippe Chantreau at 11:10 AM on 7 July 2010Is Willis Wrong at WUWT? or Sensitivity and Sensibility I
Really, should any attention be paid to that kind of nonsense? It's not like there is a shortage of interesting papers to look at. -
Paul Daniel Ash at 10:50 AM on 7 July 2010Is Willis Wrong at WUWT? or Sensitivity and Sensibility I
Mercy. The comments thread reads like the "Royal Society minutes" from Stephenson's Quicksilver:"Dr. ENT speculated as to why it is hotter in summer than winter. Mr. WATERHOUSE read a letter from a PORTUGUESE nobleman, most civilly complimenting the society for its successes in removing the spleens of dogs, without ill effect; and going on to enquire, whether the society might undertake to perform the like operation on his Wife, as she was most afflicted with splenetic distempers. Mr. WALLER mentioned that toads come out in moist cool weather. The president produced from Sir WILLIAM CURTIUS a hairy ball found in the belly of a cow. ..."
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KR at 10:43 AM on 7 July 2010Tai Chi Temperature Reconstructions
johnd - my last sentence in my previous post was stating that perhaps the similarities in reconstructions (from various sets/subsets of proxy data) indicate that they are correct. There is independence in the samples - oxygen ratios in ice cores are calibrated completely differently from borehole temperatures, from tree ring analysis (which I have worked on a bit), stalagmite growth, etc. That really invalidates your assumption of everything being calibrated to the same benchmarks, and hence suffering from a common mistake. There is sufficient independence in the sample set. -
Lou Grinzo at 10:37 AM on 7 July 2010Is Willis Wrong at WUWT? or Sensitivity and Sensibility I
If reading this treatment of Willis' post doesn't make your head explode, I suggest hopping over to WUWT and reading the comments. They are, shall we say, revealing. -
Riduna at 10:06 AM on 7 July 2010Archibald’s take on world temperatures
Arkadiusz Semczyzak at 31 Thank you for the reference. The point I was trying to make is that solar activity has been low for the past 40 years but is now showing signs of increasing. During that same period of solar quiescence, global temperatures have continued to rise and, as solar activity becomes more pronounced, we can expect global temperatures to rise even more rapidly than they have so far. This should concern, particularly to those who believe that present measures to limit rise in temperature to 2C by 2100 will be effective. They will not, certainly not in Australia or North America where there is little concerted effort to reduce greenhouse gas emissions. -
Icarus at 09:25 AM on 7 July 2010Is Willis Wrong at WUWT? or Sensitivity and Sensibility I
Think that should have been 400W/m², not 560... but it still means an infeasibly huge forcing would have been needed to get the planet out of the last ice age. -
Icarus at 09:12 AM on 7 July 2010Is Willis Wrong at WUWT? or Sensitivity and Sensibility I
Wow indeed. According to Willis's value for climate sensitivity, the ~7°C rise in global average temperature at the end of the last glaciation must have been caused by a whopping 560W/m² change in forcing. Guess that means the sun must have warmed up by about 40% at that time. He should tell the astronomers, I'm sure they'd be fascinated to hear that. -
Tai Chi Temperature Reconstructions
johnd, One of the skeptic arguments that this post is addressing is that the reconstruction data is "fudged" to produce a particular result. Peter's confirmation of the methods refutes that point. Someone holding this point of view may indeed find Peter's results surprising. -
johnd at 08:10 AM on 7 July 2010Tai Chi Temperature Reconstructions
skywatcher, your parallel is virtually what I was saying. The point being that more labs coming up with the same results only confirms that the methods used to process the data only confirms that they all use the same methodology given it is all the same raw data. It really is not confirming whether the data is a representative sample or not. Thus it is no different to carrying out a reanalysis of a urine sample. Your use of tree rings as an example is very relevant. The Briffa tree ring reconstruction began to diverge where the very highest quality data obtainable was available to validate all the assumptions made and equations developed inputted into the reconstruction model. ..................... KR, your last sentence also agrees with what I was saying. Repeated processing of the same sample only provides confirmation that the methodology used to process it is consistent with all other methods that produced the same results. Peter has obviously put a lot of effort into producing the work, and my response was to his own comment, "the fact that this resembles all of the other recent published reconstructions may (or may not)be surprising" I felt that the results were not surprising and set out to explain why I thought that. Perhaps anyone who found the results surprising can explain why they found them so. -
JMurphy at 08:01 AM on 7 July 2010Peer review vs commercials and spam
Sorry, previous comment directed towards hucmht -
JMurphy at 08:00 AM on 7 July 2010Peer review vs commercials and spam
You could do worse that have a look at (meteorology) Professor Scott Mandia's blog, where he has looked into that fallacy : Part I Part II Also, have a look at the Industry, Energy, Biofuel, etc. groups that are engaged in lobbying and spending millions of dollars (also shown in the previous link) : The Center for Public Integrity. -
daniel at 07:48 AM on 7 July 2010Sea level rise is exaggerated
Ok but it will take me sometime as, like the rest of you, I am a busy man. I would also like to point out to Peter that this comment: "Add to this data from other sources which also give points with high uncertainty but which also fit on the shallow curve (given the error envelope) increase the probability of the low amplitude variation fit being statistically robust, and diminish further the probability of your hypothesis being correct." has already been discussed in part by both of us. He asked me to examine Donnely 2006 and made the claim that the papers support each other but Donnelly 2006 is an even sparser data set than 2004 with all of the 2004 data fitting within the two latest samples of 2006. The 2006 data has just as much or even more uncertainty than the 2004 data. So how is it that either refine the other? I guess the answer will be read the other papers and they will do better? I will, but I doubt they will do the job. Also I have been told that high res studies are in agreement with the overall conclusion of Donnelly's paper. But I have read the Gehrels 2006 high res study and the uncertainties still undermine the validity of a recent unnatural uptrend (not to mention a highly suspicious uptrend when the method of age determination changes). Will the other papers cited like Grinsted do any better? We'll see but from what I've seen and keep seeing when asked to read these studies is that they will probably all have much the same faults because the nature of the measurement doesn't have the certainty required to detect a moderm uptrend. -
kdkd at 07:44 AM on 7 July 2010Astronomical cycles
Ken #135If there is no 'offset' in the Topex-Jason 1 splice, then the better curve match is non-linear - which may well be a true record of what is happening with SLR.
Nope, this is wishful thinking. You need to do the statistics to demonstrate this not eyeball the data and come to a conclusion based on your preconceived notion of what you want to find. There really is a lack of joined up thining in your argument. Addressing my questions at #133 would help address this problem of yours. -
scaddenp at 07:22 AM on 7 July 2010Arctic Ice Part 2: A Review of Factors Contributing to the Recent Decline in Arctic Ice
Arkadiusz Semczyszak - so GW is caused by change in THC, rather than other way round? Explain then stratospheric cooling and CO2 signature in radiative spectrum please. -
Peter Hogarth at 07:15 AM on 7 July 2010Arctic Ice Part 2: A Review of Factors Contributing to the Recent Decline in Arctic Ice
Arkadiusz Semczyszak at 00:11 AM on 7 July, 2010 I will not simply dismiss your “bold” claim. Let us see if there is evidence that weighs in its favour, and what evidence weighs against it. As you seem to propose something like GHG theory in reverse? (in terms of cause and effect) this could be interesting. If I am understanding your proposal that changes in the Arctic lead effects elsewhere, and I found evidence that peaks in Arctic temperature lagged behind both Antarctic temperature and CO2 peaks in ice core data, this would be a problem for your hypothesis, but might support a GHG hypothesis? See Ahn 2008, Ocean circulations may be involved, but what leads what?
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hucmht at 05:27 AM on 7 July 2010Peer review vs commercials and spam
I wasn't sure where to put this comment but I had the argument thrown at me: "Keeping the grant/research $$ flowing is a strong motivation. Scientists will write grant proposals and research questions they know will get them money and approval. Science is just another business, and global warming is just the current hot product. " Can you help refute this one please? -
skywatcher at 05:11 AM on 7 July 2010Tai Chi Temperature Reconstructions
johnd - you seem to be suggesting that somehow, by calibration to a 150 year temperature record, 2000 years of variations can be 'forced' to have a particular shape (do you mean the 20th Century 'uptick')? This is obviously crazy. If that were the case, you would get unusually good correlations during the instrumental period, and the relationships would degrade spectacularly as you headed back into palaeoclimate. Peter Hogarth's excellent graphs show this specifically not to be the case. That they don't diverge indicates no specific calibration directly to the temperature record. Each method will have its own calibrations, such as oxygen isotopes for the ice core records. but that does not force each reconstruction to have the same features, as you are suggesting. The reconstructions are free to vary dependent on the palaeo data, not on some forced 'fit'. That they can be simply averaged in this way shows that these methods and samples are providing generally the same pattern independently of each other. This is utterly different to carrying out a reanalysis of a urine sample. The parallel would be to take the same series of raw tree rings and sending it to different labs to produce a reconstruction - each lab ought to produce a very similar curve based on that specific sample. Another set of tree rings might produce a quite different curve, applying the same methods. Generally, the different curves have similar features, as Peter has identified, suggesting something about palaeoclimate. -
KR at 04:28 AM on 7 July 2010Tai Chi Temperature Reconstructions
johnd - I'm a little confused as to what you are getting at here. You (correctly) note that proxies are calibrated - for example establishing how growth rings vary with temperature. There have been in the past a few issues with calibrations for forensic and other samples, but not often - ground truth has a tendency to correct these errors over time. The only thing I can read into your post is an assertion that 50+ different proxies could be so poorly calibrated as to throw off the averages. Given that each of these paleotemp reconstructions has it's own calibration, experimentally determined by separate groups from multiple disciplines, I think there are more than enough independent samples to make this kind of reconstruction reasonable. "When a reconstruction is done that produces results similar to other reconstructions" - perhaps, just perhaps, they're accurate reconstructions! -
CoalGeologist at 04:09 AM on 7 July 2010Tai Chi Temperature Reconstructions
Fascinating trend. Nice work! Assuming it stands up to more rigorous treatment, the "smoothed" global trends are quite interesting. The author, Peter Hogarth, has been understandably careful about drawing any conclusions regarding causation, but Commenters arguably have greater liberty to consider this trend in the context of what is presently known about climate drivers (w.r.t. temperature, in particular). There is no significant energy source for warming the atmosphere and hydrosphere other than the sun, so we can limit the possible controls to two categories: 1) Variation in the amount of solar energy entering the atmosphere, and 2) Variations in the amount of solar energy retained (until the rates of emission and absorption are balanced, (any "missing heat" notwithstanding!)). The controls for past variations are uncertain. The present warming, however, is largely driven by the ever increasing concentrations of GHGs, together with associated feedback mechanisms, there being no evidence (so far, at least) that any other factors have played a significant role. We are left to speculate (or to investigate!) how the 1000 year trend from 900 to 1900 might have continued if it had not been influenced by human activity. Could anthropogenic CO2 have rescued us from continued cooling? More important, how will the unprecedented introduction of massive quantities of CO2 affect future warming? To the extent that we may have the ability to "tweak" Earth's climate in the future, it's a fascinating, and extremely important question. -
johnd at 03:59 AM on 7 July 2010Tai Chi Temperature Reconstructions
Peter, the fact that your reconstruction resembles most others is not surprising. Doing reconstructions such as you have done is similar to the situation with analytical laboratories around the world. Irrespective of whether the laboratory is testing blood and urine samples, or bulk materials, once the sample has been taken, it could be sent to any reputable laboratory anywhere in the world and the results should be all the same. The reason for this is that the methods used are all calibrated against the same bench mark, and this will be the case here too. All proxy reconstructions have to be calibrated against a known benchmark, and for proxy temperature reconstructions, that will have been the instrumental temperature record. Getting back to the laboratory analysis, if the results are doubted or subject to dispute, as does happen at times if the results form of a commercial arrangement, then there is little point in ordering the samples to be retested, or tested in another laboratory as procedures are such that all laboratories will generally produce the same results. If there is a real problem, it will be that the sample provided is not truly representative, and the solution is to collect a new independent sample and analyse that. The problem with doing temperature reconstructions is where do you get an independent sample that has not been validated against the same benchmark as every other sample? When a reconstruction is done that produces results similar to other reconstructions, what is really being proved is that the method used to produce the results is probably correct given it is basically the same samples that are being analysed. This is basically the same as doing "round robin" testing where one sample is tested by a number of laboratories to confirm that their in house procedures are in line with each other, and the industry standards. Such exercises do nothing to confirm or otherwise that the sample tested is indeed a representative sample of the what it was sampled from originally. -
Alexandre at 03:35 AM on 7 July 2010Tai Chi Temperature Reconstructions
Very nice post. I´d like to see more "playing around" with the data like this. It would be nice to see the difference between northern and southern hemisphere, or how robust the series is to different proxy choices, or how geographic distribution changes the result. In fact, if I find the time I´ll try some experiments myself. Thanks, Peter! -
Rob Honeycutt at 03:33 AM on 7 July 2010Tai Chi Temperature Reconstructions
Peter... You honor me greatly, most respected si fu (master). Looking at paleo climate charts I'm always struck by one thing. How it's almost impossible to get an unbroken perspective on current warming relative to historic warming. For the science crowd it's not a problem. This chart of shorter time scale picks up where the other chart of longer time scale leaves off. But for the broader lay person it creates a discontinuity that doesn't always translate. Take your figure 3. The current temp trend is SO vertical that it disappears along the side. I know you pick it up in the following charts but you've just published a chart that any climate "skeptic" can take out of context and say, "See, Peter Hogarth even says that we're not warmer that the MWP. Here's his chart." I believe Michael Mann does a pretty masterful job in presenting his charts in various clever ways that generally manage to avoid this. Of course he has funding and you're doing a blog post on your own nickel. The very best charts, IMHO, are the animated charts being created by NOAA for the Time History of CO2 which were reported on SkS here. This is an amazing reconstruction job you've done, Peter. (I love this stuff!) The one chart I'm longing to see, though, is this temperature reconstruction you've done in the style of NOAA's animated chart. Or, even better, the two overlaying each other. Temp and CO2. With a good narration I think this would be one of the most compelling graphics created on the issue of climate change. Unfortunately it's a task that is well outside of my own skill sets. -
Peter Hogarth at 03:30 AM on 7 July 2010How Jo Nova doesn't get the CO2 lag
Bill Stoltzfus at 01:52 AM on 7 July, 2010 I haven't checked the JoNova charts, but if you can drive Windows Excel or other chart/spreadsheet programs you can download more up to date data from the NOAA Paleo (Ice Core) website and make your own charts. For 800k years of CO2 look at Luthi 2008, EPICA Dome C data series (he has a composite including Vostok), and for temperature look at Jouzel 2007 from the same site. I think they have the most consistent EDC3 ice age/gas age dating. This and the quoted uncertainties are something to strongly consider when judging lag. -
Peter Hogarth at 03:07 AM on 7 July 2010Astronomical cycles
Ken Lambert at 00:16 AM on 7 July, 2010 I think a point I made in the sea level post was along the lines of the satellite trend and recent continuation of the overall longer term curve fit derived from tide stations is statistically indistinguishable. For the overall satellite trends a first order linear fit is as good as any. This trend may change, upwards (or downwards) with much passage of time, and I would hope in line with the overall tide station data, but currently if warming and increasing ice loss are accepted as drivers, and we accept what the ocean observing community is telling us on how close we are to balancing the sea level budget, then it is difficult to imagine the trend reducing anytime soon. I actually agree fully with your last point on respecting the uncertainties, and here we must strive to both improve the knowledge of deeper ocean temperature trends and look at the upper ocean values from the various sensors and other sources (GRACE and Acoustic methods) and see if the bias problems identified over the past few years have been completely "fixed" or not. However I warn against automatically seeing jumps where there is high variability anyway, and lack of knowledge does not disprove anything... We still appear to have rising sea levels with a strong thermal component. This "thermometer" is difficult to ignore. On balancing the energy budget I haven't read much as yet beyond Trenberth, and noting the high (relative to "unaccounted" heat flux) uncertainties in the satellite global TOA/Surface IR radiation measurements. -
chris at 02:43 AM on 7 July 2010Astronomical cycles
Ken - you're making a meal of this. If you wish to take "due respect for the uncertainties and inconsistencies with reconciling SLR and OHC given the current state of knowledge", then that should be applied across the board. If one looks at Trenberth's analysis of the heat budget during the short period 2004-2008, then there is an apparent shortfall, although the error bars overlap. You're correct that I made a double accounting of the TSI contribution - my mistake. Otherwise the apparent shortfall during this short period amounts to ~ 0.2 - 0.69 W. As Trenberth states, this might possibly be accounted for by sequestration of some heat into the deeper oceans during this period....there may be other explanations. Is there anything more to be said about this? I don't think we can draw any particular conclusion at this time. Sea levels have risen quite rapidly during the last 18 months and as Trenberth states the recent warming may be in indication that the "missing heat" is reappearing. I expect we will have a better idea of the situation during the next few years. Otherwise I'm not sure this really merits the degree of insult and monothemic badgering that you're engaged in. Perhaps it would help if you could be a little more specific about what you are trying to achieve or what you wish to draw from the data presented by Trenberth. And you do need to address the analysis more rigorously. Your "respect for uncertainties...." and "looking hard at composite charts....", apparently equates to drawing regressions of bits of the data and noticing that these don't meet at the ends. That's simply bogus with respect to identifying offsets. I've linked to a series of papers in which the question of merging satellite sea level data is addressed in great detail. You don't seem interested in that but you should be if you sincerely have "respect for the great uncertainties.....". Likewise, we have analyzed the satellite data with a quadratic fit. The quadratic fit is so close to a linear fit (the "acceleration term" of the quadratic is close to zero) that it makes little difference. So the satellite data conform rather closely to a linear fit (with some wiggles). That's a simple fact Ken. You seem sufficiently unhappy about the fact that current sea levels are pretty much smack on the long term linear trend defining the satellite era data that you feel I should be pilloried for pointing this out! Oh well.... -
Bill Stoltzfus at 01:52 AM on 7 July 2010How Jo Nova doesn't get the CO2 lag
I was looking at the Vostok graphs at Nova's site (specifically the last one), and was wondering about a couple of things. Perhaps I should ask this first, though--is her graph a valid one to look at, or is there a better one? There are a few places where the temp and CO2 lines go in opposite directions, or don't seem to follow the lag rule. Around 50,000 years ago they don't match up well. 160,000 to 170,000 years ago there are several temp spikes with no CO2 movement. About 375,000 years ago temp spikes while CO2 continues downward. I realize these are only a few places out of hundreds of thousands of years of history, and you've said before that CO2 is not the only climate driver, and it's possible that the time resolution isn't detailed enough to show all of the movements, but I am wondering what effects could suspend or negate the CO2 lag? Is the concentration change in CO2 not enough to overpower other effects? Thanks.
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