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Comments 118751 to 118800:

118751. Riccardo at 01:20 AM on 25 May 2010
        Robust warming of the global upper ocean
        Actually I have some difficulty on the critics people are making here. The aim of the paper was exactly to address the well known problem of XBT vs Argo periods. The final result is the black curve in fig. 2 here. It shows a steady increase starting around 1998 (or earlier) and a smaller (not null) trend after 2003/04 for the next 5 years. The authors are, of course, well aware of the possible meaning: "The fact that this transition occurred at the same time as the flattening could be oincidental, but also raises the possibility of a yet-undiscovered bias in the observing system." Trenberth 2010 adds that substantial warming is found when considering the full depth data "indicating that substantial warming may be taking place below the upper 700 m". ((Some more details here). It's surprising how people can be so superficial to claim they know the answer by eyeballing the graph and without, apparently, any evidence but "coincidence". For scientists it is left as an open question, as it should. Neverthless, this dataset represents the best of our knowledge, given the joint effort to produce it. As for TOA imbalance, OHC trend and the like, never forget that we all know that it's a travesty we cannot track the flow of energy through the climate system in the short run.
118752. Paul D at 01:18 AM on 25 May 2010
        Greenland rising faster as ice loss accelerates
        Tony O, @8: Here in the UK we have an isostatic rebound that equates to 1 or 2mm per year. Depends how much you are talking about. Clearly an inch in the UK will take a few years, but that is not thousands.
118753. Doug Bostrom at 00:37 AM on 25 May 2010
        Robust warming of the global upper ocean
        I've not heard anybody yet be so bold as to dismiss the entire instrumental record- splices and other warts included- as "just nonsense." Is anybody expressing skepticism of this result prepared to explain how the OHC difference between the left and right ends of the graph is "just nonsense?" If so, can you explain exactly how so many years of data was collected and so much work expended in a meaningless effort? Can you do that in detail?
118754. Tony O at 00:03 AM on 25 May 2010
        Greenland rising faster as ice loss accelerates
        I thought the isostatic rebound was supposed to take thousands of years. This is surprisingly quick, even for a doomsayer like me. Can we now expect volcanic activity in Greenland? How will Niels Axle Molnar spin this?
118755. Ken Lambert at 23:30 PM on 24 May 2010
        Robust warming of the global upper ocean
        BP#6 has probably got the intepretation about right. Figure 2 shows a huge increase in OHC from roughly a 2 year period 2001 to 2003 in which the OHC rises from the zero axis to about 7E22 Joules or about 700E20 Joules. This is about 350E20 Joules/year heat gain. Dr Trenberth's 0.9W/sq.m TOA energy flux imbalance equalled 145E20 Joules/year. Therefore a rise of 350E20 Joules/year in OHC equals about 2.1W/sq.m TOA imbalance - a seemingly impossible number. Coinciding with the start of full deployment of the Argo buoys around 2003-04 this impossibly steep rise in 2001-03 looks like an offset calibration error. Similar would apply to Fig 3. In such case, fitting a linear curve from 1993-2009 and calling it a 'robust' 0.64W/sq.m is just nonsense. One might also note that the better the Argo coverage and analysis gets from about 2005 onward - the more the teams curves converge on a flattening trend - no OHC rise - no TOA imbalance.
118756. Arkadiusz Semczyszak at 21:34 PM on 24 May 2010
        Unprecedented Warming in Lake Tanganyika and its impact on humanity
        I think that "threatening" Africa's alleged harmful effects of climate change - for the people (here fisheries), finished as those for malaria: "Climate change and malaria, the global recession" - Gething et al., 20.05.2010, Nature. (I hope separate comment JC on this) "First, widespread claims that rising mean temperatures have already led to increases in worldwide malaria morbidity and mortality are largely at odds with observed decreasing global trends in both its endemicity and geographic extent. Second, the proposed future effects of rising temperatures on endemicity are at least one order of magnitude smaller than changes observed since about 1900 and up to two orders of magnitude smaller than those that can be achieved by the effective scale-up of key control measures. Predictions of an intensification of malaria in a warmer world, based on extrapolated empirical relationships or biological mechanisms, must be set against a context of a century of warming that has seen marked global declines in the disease and a substantial weakening of the global correlation between malaria endemicity and climate." I hope that this ERROR WHO, WWF, UNEP and, the parts, IPCC (here, the fact in IV report presents the question, but ...) once again makes people think about the REAL effects - "impact on humanity" - of global warming ...
118757. Arkadiusz Semczyszak at 20:59 PM on 24 May 2010
        Greenland rising faster as ice loss accelerates
        Such large differences for the same latitudes indicates that the decisive role played by atmospheric and oceanic circulation - their changes. Note that some glaciers Fennoscandia over the past two decades have increased their range and volume. Increasing range of THC to the north, particularly well explains the imbalance between NE and NW Greenland, Canada. It is true that the Gulf Stream has too little energy, but by changing the albedo of the Arctic Sea (melting sea ice) ...
118758. Marcel Bökstedt at 19:14 PM on 24 May 2010
        Robust warming of the global upper ocean
        Bérenyi Péter> Yes, the behaviour of the bias uncertainty around 2006 should be reated to the shift to ARGO. The more curious thing is that the bias-related uncertainty goes up from 1996 to 2000, but maybe you solved that too, if the XBT system was deteriorating, this could introduce more uncertainty. I don't quite see how the increase in ocean heat content up to 2003 can be a measurement error due to change of instrumentation, it seems that the old XBT system was still in place (possibly on a lower level), so there was no big change of instruments there? The recent argo data seem to present a big problem. There are several things to explain simultaneously. Why did the upper level ocean heat content rise in 19993-2003, and then stop rising? Can we account for both the total energy content ("closing the energy budget") and the observed sea level rise? As long as we can't explain all of this, something is so missing. A mechanism to transfer heat down into the ocean would be one possible way to start resolving it. It might not work out of course. If the ocean is taking up less energy recently, this just leads to a new mystery: Why did the behaviour of the ocean suddenly change in 2003? From Peru> Figure 1 are the original curves as published by various authors. In Figure 2 the same curves have been recomputed with changes in the input data. That is, they use the same method of bias correction as the original authors, but with three types of homogenizations in the input data. The homogenizations used with a certain bias correspond to the three curves in fig 2 with the same color. So it is not so surprising that the curves in fig 2 are closer than those in fig 1, some (but not all) or the causes of difference has been eliminated. I believe that the reason for that the authors are doing this is to analyse the difference between published estimates of OHC. The idea is that the differences come from several independent differences in the approaches: The dataset, the bias correction method, and the choice of baseline climatology (I'm still not sure what the last means, but something like what period is considered as baseline).
118759. Riccardo at 19:06 PM on 24 May 2010
        Robust warming of the global upper ocean
        A joint effort between groups (usually in competition) to improve the scientific understanding is a great thing. Congrats. From Peru, this is exactly what this new paper is addressing, the switch from XBT to Argo floats.
118760. chris1204 at 19:02 PM on 24 May 2010
        Greenland rising faster as ice loss accelerates
        Greenland seems to be subsiding (or perhaps showing decelerating uplift) pre-2003 (as best as my rough eyeballing can make out). Canada seems to be on a slight decline or decelerating uplift (whether significant or not I've no idea). Iceland's see-saw might be the result of its unique tectonic location. But why would Greenland see-saw?
118761. Riccardo at 18:56 PM on 24 May 2010
        There's no empirical evidence
        PaulK, indeed F(t) is not equal to I(t)−O(t). No one ever said it is, Tamino even wrote it explicitly. Let's see if you like a different wording more: I(t) = Ie+F(t) O(t) = Oe+λΔT(t) (to first order) I(t) − O(t) = Ie + F(t) − Oe − λΔT(t) = F(t) − λΔT(t) with Ie and Oe equilibrium values. Straightforward, I'd say.
118762. Jacob Bock Axelsen at 18:44 PM on 24 May 2010
        Are we too stupid?
        embb, I have read all your references and answered all of your questions above. The trivial pretext of preventing 'carbon leakage' versus your question of taxing all products of defectors are two different issues. In general, taxes do not hurt the economy. They change the fluctuations from extreme values (catastrophic climate change, financial crashes) to something more benign, say, steady growth with finite moments. This is what everybody wants, and that is not even counting the benefit of investing the revenue in sustainability. The anti-'carbon leakage' customs tax is trivial because it would not hurt anyone undeservedly. The companies would still benefit from other advantages of unregulated locations, the temptation to move would just be smaller and the poor nations would have an excuse to start regulation. The US will not put a carbon tax on every product coming from countries that do not have a carbon tax by next year. The most urgent question would be which international treaty sets the standards? The US defected on Kyoto and they are not the cleanest producers per capita themselves, so which entire countries would they actually punish? In fact, with China and the EU leading the race they might face large reciprocal punishments. That is were the next treaty comes in. And never forget: everybody will benefit from preventing climate change in spite of the transient pain of moving to a sustainable economy - because it is cheaper in the long run.
118763. Arkadiusz Semczyszak at 17:16 PM on 24 May 2010
        Unprecedented Warming in Lake Tanganyika and its impact on humanity
        @jtierney "Given this long paleoclimate contexte, the recent warming really does Appear To Be Atypical for the lake." Looking at the combined graphs of your works - papers in 2008, and 2010, even without the use of statistical calculation to smooth the data (eg average filter, or Fourier analysis), shows excellent activity cycle of the sun - circa 6000 years (Xapsos and Burke, 2009). What has to rely so that "recent warming really does appear to be atypical"?
118764. Doug Bostrom at 17:13 PM on 24 May 2010
        Greenland rising faster as ice loss accelerates
        It's an odd thing that Nature does not charge for supplementary material. I just noticed this quirk recently.
118765. Doug Bostrom at 16:58 PM on 24 May 2010
        Greenland rising faster as ice loss accelerates
        Extra-juicy supplementary material for article complete with depressingly curvaceous graphs freely available here.
        Response: Thanks for the link, Doug. The paper kept refering tantalisingly to the supplementary material but I assumed it was stuck behind a paywall and didn't bother looking. Here's a short excerpt:
        
        
        
118766. PaulK at 16:43 PM on 24 May 2010
        There's no empirical evidence
        e, To expand a little on Riccardo's comment. The physics says that if one applies a positive impulse forcing to a system in steady state (input power equals output power), then the system will heat up. As the system heats up, it will increase its power output until the temperature restabilises at a new constant value. The small issue I have with Riccardo is definitional. If the input power is I(t) and the output power is O(t), then at time t0, in steady-state, we have I(t0)-O(t0) = 0. If one defines the net forcing over time, F(t), as the difference between input and output power, i.e. F(t) = I(t)-O(t), and one applies an impulse forcing F(t0) to the system, then to restore steady-state, F(t) must then decay to zero after a period of time as temperature restabilises. However, the expression used for F(t) in Riccardo's heat balance equation (C dΔT/dt = F−λΔT) is not a net forcing over time. Instead, it is equal to the difference between the input power at time t and the output power at time, t0. For this expression to make sense, mathematically, F(t) = I(t) - O(t0) - equivalent to a series of stacked impulse forcings applied to the input side of the power equation.
118767. David Horton at 16:40 PM on 24 May 2010
        Greenland rising faster as ice loss accelerates
        Yes, Doug, I'm waiting for the first comment that says, well, of course, this is only Greenland!
118768. Doug Bostrom at 16:37 PM on 24 May 2010
        Greenland rising faster as ice loss accelerates
        Convergence as David says, unless somebody can put together a detailed explanation of how all the relevant observations are wrong in a way that coincidentally resembles coherence. Remember that requirement when folks begin quibbling over accuracy of one set of observations or the other; hypothetical errors have to somehow converge.
118769. Doug Bostrom at 16:26 PM on 24 May 2010
        Robust warming of the global upper ocean
        That's a really useful (and fascinating for instrument enthusiasts) compendium of information, Ari. Here's the relevant section on various errors which have cropped up as the ARGO system has gone through its "teething pains" and adolescent years: "In 2003, it was found that problems with the Druck Pressure Sensor were causing some floats to stay at the surface for prolonged periods and eventually to become surface drifters. The Druck Pressure Sensor is the successor to the Paine pressure sensor in Seabird CTDs. Even when not severe, the problem may have caused errors in the salinity measurement due to increased biofouling due to prolonged surface exposure. When the problem was found, the CTDs were recalled and the source of the problem was fixed, but this was not possible for floats already deployed. A large number of SOLO floats with FSI CTD packages deployed in the Atlantic Ocean between 2003 and 2006 were found to have a pressure offset problem due to a software error. This error caused pressures to be paired with the temperature measurements from the next lower level, creating the illusion of a cooling ocean. Once the problem was found, a list of such floats was compiled. An effort was made to correct the problem, successful in some floats, not in others. All data from all these problem floats are included in WOD09. For those data which could not be corrected, all float cycles are flagged. More recently, in early 2009, a problem with the Druck pressure sensor has been found (J. Willis and D. Roemmich, minutes of 10th meeting of International Argo Steering Team). This problem causes pressure sensor drift after deployment. Deployment of new floats was halted temporarily, until the pressure sensor design could be altered. Already deployed APEX floats are being monitored closely for sensor drift. The full extent of this problem is not yet apparent"
118770. David Horton at 16:19 PM on 24 May 2010
        Greenland rising faster as ice loss accelerates
        And still, sadly, the totally independent lines of evidence all confirm each other.
118771. Ari Jokimäki at 15:54 PM on 24 May 2010
        Robust warming of the global upper ocean
        NODC data seems to contain some cooling biases relating to Druck pressure sensors which have not been corrected. These problems start in 2003: WORLD OCEAN DATABASE 2009 (see chapter 6.6 for data problems)
118772. thefrogstar at 15:39 PM on 24 May 2010
        Unprecedented Warming in Lake Tanganyika and its impact on humanity
        Albatross (#121), Doug Bostrom (#122), Phila (#123) [This topic has been plagued by remarks diverging entirely away from discussion of the Tierney paper. Thefrogstar's comment while very long did not actually refer to the paper under discussion even once. After editing out the irrelevancies, all that is left is this.]
118773. Doug Bostrom at 15:15 PM on 24 May 2010
        There's no empirical evidence
        What, I'm supposed to take your word for it, PaulK? Sorry, not until you work it out w/Tamino directly. If he says you're correct then congratulations. But based on your waffling w/Riccardo I doubt you'll end up w/anything to celebrate.
118774. PaulK at 15:01 PM on 24 May 2010
        There's no empirical evidence
        Doug_Bostrom, I have now discovered that "Tamino" is the blog pseudonym of the author of the site to which Riccardo referred me. You wrote: "I may be wrong but as far as I know Tamino has never been found wrong w/regard to posts he's made on his site." I am then especially honoured to have been the very very first to have done so. Thank you. Riccardo, You introduced the reference to Schwartz to counter my arguments about the difficulty of reconciling various assumptions to an observed increase in OLR. Can we now agree that one cannot derive an expression for OLR from the Schwartz model in the way you attempted and return to the main thrust of the conversation? This is a serious, not a provocative, question. The impatience I expressed in #68 was because I suspected that you already understood the implications of my comments on interpretation of the F term in Schwartz, but you did not wish to acknowledge this. However, this may not be true, and hence, my question. Do I need to expand further on this subject? Do you question my interpretation of the Schwartz model? Or can we agree and move on?
118775. Marcus at 14:20 PM on 24 May 2010
        Robust warming of the global upper ocean
        What I see from that close up is a "wobble" between 10*10^22-13*10^22 Joules between 2004 & 2009. The peaks seem to correspond quite nicely to periods of higher & lower atmospheric temperature. Also, Berenyi, you mustn't forget that incoming solar radiation was also falling significantly over this time period, which might also explain an overall lack of growth in the Oceanic Heat Content.
118776. e at 13:47 PM on 24 May 2010
        Climate's changed before
        Roger > "Are you telling me you can do this for previous warm periods (when there was no anthropogenic CO2) as well and get an intelligible result?" Yes! You seem to be under the misconception that current theories of climate include only CO2 and nothing else. This is not the case. As scaddenp pointed out, current theories of climate take into account all known forcings, not just GHG's. As for how we can have warming in the past when CO2 is low, and warming now that can be attributed to CO2, imagine a room with two heaters: Let's call them heater 1 and heater 2 (since I'm not very creative). Now let's say I told you that if I turn up heater 2 without changing heater 1, the temperature in the room will increase. Hopefully it is pretty self-evident that this is true. What you are arguing is that the room was warmer in the past, and heater 2 was set low, therefore heater 2 could not possibly have a warming affect on the room. I hope you can see the mistake in that line of thought. Clearly, it is possible that heater 1 was set high at a time when heater 2 was stable, thus leading to warmer temperatures in the past. This does not preclude the fact that heater 2 can have a warming effect right now. In this analogy, think of heater 2 as greenhouse gasses and heater 1 as solar irradiance (or any other non-GHG forcing). When the earth was warmer in the past while CO2 was low, other forcings were responsible for the warming (such as the earth being generally closer to the sun due to cyclical changes in our orbit). Scientists know this because they can reconstruct the historical levels of forcings and global temperatures, and analyse the relationships between the two. What they conclude is that man-made CO2 was the primary driver of warming in the past 30 years. This is reason why past climate change acts as evidence for AGW, which is the point of this post. One final note: dozens of climate models have been developed that can accurately recreate both past and present temperature trends. Out of all these, none have been able to recreate real world temperature trends without confirming that CO2 was the primary driver of warming in the past 30 years. Is this all just a coincidence?
118777. From Peru at 13:38 PM on 24 May 2010
        Robust warming of the global upper ocean
        One curious fact: in figure 1, there is a considerable divergence between the datasets after 2003. In figure 2, they seem to converge as they approach present time (roughly 2009). What is the reason?
118778. Doug Bostrom at 11:31 AM on 24 May 2010
        Climate's changed before
        Roger, off-topic but I've visited your archive of failed conversations and find it quite interesting. You refer to it as "My Other Blog where I record conversations that Global Warming Protagonists put in the "too hard basket", an ironically accurate description from my perspective. It is indeed too hard, impossible really to have a productive conversation when one's conversational partner refuses to address evidence that is accepted by what is arguably one of the premier scientific bodies as uncontroversial. You say of the NAS report I mention earlier "...I expect you to use your brain to discuss my point. I dont give two hoots what the NAS says, unless they can show me how the "Anthropogenic CO2 causes Global Warming" hypothesis is proven. Now that would be not unreasonable to expect from a bunch of scientists right? I'd suggest that as you are the person making an assertion that flies in the face of facts, the onus is on you to provide a detailed rebuttal to the NAS report. You should do so in a way leading a reasonable person to conclude that "a bunch of scientists" practicing in domains directly related to climate science as opposed to economics are lacking in the insight necessary to conclude as they do that "Some scientific conclusions or theories have been so thoroughly examined and tested, and supported by so many independent observations and results, that their likelihood of subsequently being found to be wrong is vanishingly small. Such conclusions and theories are then regarded as settled facts. This is the case for the conclusions that the Earth system is warming and that much of this warming is very likely due to human activities." Failing that, I'd say you've invited yourself into another conversation that is "too hard", too hard for you. But perhaps raw pugilism without hope of victory is your main objective. I can't say.
118779. Rogerthesurf at 10:35 AM on 24 May 2010
        Climate's changed before
        Response, Yes expecting a reply to Comment 82. Rather do it on this forum if thats OK Cheers Roger
118780. sylas at 10:03 AM on 24 May 2010
        Has the greenhouse effect been falsified?
        Hi Berényi Péter; thanks -- sorry if I was over sensitive. I am reassured and happy to continue to explain what is necessary for your concerns, and to keep fixing any errors I have allowed into the essay! The main thing I can do at this point is assure you that the plot in the Figure is one is of real measurements, unscaled; and there's nothing particularly unexceptional about them. The IR transmittance for those observations is clearly well over 80%, as you note, but this is not unusual. It is not a global average, but a nice clear sample for comparing up and down fluxes in the Arctic. Essays and textbooks can indeed have errors, as we've seen in my writing here as well! But the specifics of the figure here are not an error. You've got a nice open IR window there. Other spectra will show other characteristics of the conditions at other times and places, and this is indeed very interesting -- but I don't understand the point. They ALL show the greenhouse effect at work, and there's nothing to cast the slightest doubt on the figure I used. Dave Tobin is a busy working scientist and I appreciate his willingness to help out with this essay, but I don't want to overload him with questions when the basic fundamentals here are pretty straightforward. He has said to me unambiguously that there are real measurements, from real instruments, and that it is not uncommon to have > 80% transmission in the 10 micron window. He also points out that "we" (the various scientists involved in this work on remote sensing) have spent many careers worth of time on improving and verifying the accuracy of the measurements. The best reference for more about how this is done is a paper cited for this essay, Tobin et al 2006, which shows up in the copy under the "list of arguments" here. Follow this link: Has the greenhouse effect been falsified. Transcribing the reference to here for now, it is: Tobin, D. C., et al. (2006) Radiometric and spectral validation of Atmospheric Infrared Sounder observations with the aircraft-based Scanning High-Resolution Interferometer Sounder, in J. Geophys. Res., Vol 111, D09S02. This describes validation of atmospheric emission measurements from space, using high altitude aircraft measurements. Similar measurements obtained the upwards emission spectrum shown in figure 1. Unfortunately, the "footnote" sections on further reading and acknowledgments didn't appear here on the blog; I'll see about having them added to this blog post, maybe. I don't know what you mean about a cooling effect. There is a cooling effect in the upper atmosphere, certainly, but at the surface? I don't think so. If you really want to dig into fine details you are better to go to the scientific literature rather than this first level introduction essay. But nothing whatsoever in the details does anything to "falsify" the greenhouse effect! I recommend the references and further reading sections of the main entry as a starting point for people wanting more on the physical details.
118781. Doug Bostrom at 09:56 AM on 24 May 2010
        Robust warming of the global upper ocean
        Berényi, going from the micro and back to the macro view, do you think the graph you reproduce here should be taken as indicating no heating of the ocean? My point is, I see a lot of up-down on the scale you reproduced here but when we look at a longer interval those wiggles are overwhelmed by what looks to the untrained eye as an enormous uptake of heat. What's your conclusion? Is the entire instrumental we have completely unreliable to the point that even the little bit of data you present is meaningless? If it is meaningless, why are you using it and how can you conclude that there is a decrease in OHC in the period you show?
118782. scaddenp at 09:46 AM on 24 May 2010
        Climate's changed before
        "Are you telling me you can do this for previous warm periods (when there was no anthropogenic CO2) as well and get an intelligible result?" Yes. See the paleoclimate chapter 6, IPCC WG1 for graphs and references to papers that do this. Not one effort but many. As stated earlier, our theory of climate involves solar, aerosol, and albedo as well as GHG. Did you not look at the Benestad & Schmidt paper I referenced above? As for video - what the? This problem is the everyday reality for every scientist - that the value of peer review and why you want the person most likely to be upset by your findings to review them. We certainly see alternative hypotheses published - they just dont stand up to scrutiny.
118783. johnd at 09:45 AM on 24 May 2010
        Unprecedented Warming in Lake Tanganyika and its impact on humanity
        Marcus at 09:28 AM, of course it occurs all the time. My post wasn't examining the splicing of the core data itself, but examining if the same scrutiny was being applied to it as had been applied to other such instances as the temperature data you referred to with the Briffa tree ring proxy temperature reconstruction springing to mind.
118784. Berényi Péter at 09:45 AM on 24 May 2010
        Robust warming of the global upper ocean
        #14 hadfield at 08:27 AM on 24 May, 2010 I for one am sceptical that the data are accurate enough to support Trenberth's confident assertions about "missing heat" over a period as short as 5 years Here is a magnified version of the last 6 years from NODC Ocean Climate Lab OHC graph. It is clearly decreasing somewhat. On the other hand if recent globally averaged energy imbalance at TOA is +0.54 Wm^-2 as claimed, in six years OHC should have increased by 5×10²² Joules. It is not seen. As OHC is not measured properly in depths greater than 700 m while above it accuracy and precision has improved tremendously after 2003 due to ARGO, one has to invent a hypothetical process capable to push that much heat below the line without even touching the upper layer. I have not seen a reasonable explanation yet. If you know one, put it forward please. Until that time Trenberth's travesty is well and alive. BTW, the NODC Ocean Climate Lab has no explanation for the recent downward adjustment at their website. All they have is Levitus 2009 but of course it has nothing to say about something done in this January.
118785. Marcus at 09:43 AM on 24 May 2010
        Unprecedented Warming in Lake Tanganyika and its impact on humanity
        So further to my above post, johnd. If the data was obtained from the same site-& if the values of measurement used the same scale (either in meters or degrees C-or both) then there is absolutely nothing wrong with splicing the data. By contrast, McLean spliced weather balloon data (which was based off a 1961-1990 average) with satellite data (which was based off a 1979-2000 average), without acknowledging he'd done so, & without adjusting the scale of either data set. Because the satellite data contained a smaller anomaly (because average temperatures are warmer) it makes it look like temperatures level off around the 1970's to 1980's. This helped make the correlation between temperature & the Ocean Oscillation Index look much stronger than it really was. So you see it was how he handled the data-post splicing-which earned him brickbats, not the act of splicing itself. For a more enlightening analysis, check Here
118786. Doug Bostrom at 09:42 AM on 24 May 2010
        Unprecedented Warming in Lake Tanganyika and its impact on humanity
        Johnd, I especially like the "How about we just leave it" part, no further action required. :-)
118787. johnd at 09:38 AM on 24 May 2010
        Unprecedented Warming in Lake Tanganyika and its impact on humanity
        How about we just leave it to the authors of the study whom both Chris and Doug may consider contacting, or John Cook, who posted the lead post, to clarify what were the primary questions being asked that the study hoped to answer rather than second guessing evryone.
118788. Marcus at 09:28 AM on 24 May 2010
        Unprecedented Warming in Lake Tanganyika and its impact on humanity
        Johnd @ 133. On the issue of splicing data-it's not as big a deal as you might think, it occurs all the time. As long as the splicing makes sense, & as long as the spliced data fits the same Y-axis (or uses an appropriately labeled 2nd Y-axis) then its not really a big issue. Why the splicing in the McLean paper is so controversial is (a) it didn't make real sense (why use a mix of weather balloon & satellite data, when he could have used just a continuous weather balloon record) & (b) the data used completely different Y-axis scales, but he failed to adjust either of the data sets to make the scales match. This led to a situation where the temperature graph has a significantly smaller incline than if it had been properly scaled. He also failed to acknowledge either the splice or the difference in scales to his readers. McLean then made correlations based on this incorrectly spliced graph. Now, if you can show that the splicing of data by Tierney, that you're referring to, has been done in a way that has resulted in the same kind of erroneous final product seen in McLean's paper, then please be so kind as to point it out-otherwise, as others have noted here, you're really grasping at straws.
118789. Rogerthesurf at 09:27 AM on 24 May 2010
        Climate's changed before
        scaddenp, I am awaiting some answer from the owner of this blog, However I will comment on "You plug the known forcings into exactly the same theory of climate and you get the observed warmings within the error for estimating both climate and forcings" Are you telling me you can do this for previous warm periods (when there was no anthropogenic CO2) as well and get an intelligible result? Did you watch the video and do some thinking then? Cheers Roger
        Response: Sorry, what am I responding to? I must've missed a direct question somewhere but perhaps if you just email me a direct question, I can respond to you directly.
        
118790. chris at 09:19 AM on 24 May 2010
        Unprecedented Warming in Lake Tanganyika and its impact on humanity
        johnd at 08:51 AM on 24 May, 2010 No that's just incorrect johnd; you're being far too defensive. This paper has got nothing to do with "providing further proof of AGW", and it's pretty obvious from my posts that I think no such thing. Perhaps if you relaxed the notion that every single paper has to be either a "proof" or a "disproof" of global warming, you wouldn't need to spend such efforts in attempting to trash the ones you don't like! This paper neither proves nor disproves global warming. What it says is that the warming of Lake Tanganyika in the last 50 years has taken the temperatures to values likely higher than during the last 1500 years. The recent very marked warming really isn't surprising given that oceans and lakes (and land surface and the atmosphere) have risen globally, especially during the last 50 years (see my post just above). Although the paper isn't specifically about global warming it's entirely appropriate to interpret the work in the light of a massive wealth of prior knowledge. After all science isn't a Hermann Hesse-like "Glass Bead Game" where measurements are made but these don't have any meaning. It's entirely appropriate to interpret the data in the light of a vast amount of prior knowledge. But as far as "proving global warming", you're way off the mark. Of course one can say that the data is largely consistent with what we know of contemporary and paleotemperatures both locally and globally, and the causal relationships involved with these...
118791. Riccardo at 09:12 AM on 24 May 2010
        Robust warming of the global upper ocean
        hadfield, actually Trenberth 2010 is calling for more and better data: "This discrepancy suggests that further problems may be hidden within the ocean observations and their processing. It also highlights the need to do better, and the prospects for that." John, the link to Lyman is still broken in the caption of fig.2. Link to Trenberth is broken both in the caption and in the text.
        Response: Okay, I think all the broken links are now fixed, all 7 of them. Not my best work.
        
118792. Doug Bostrom at 09:06 AM on 24 May 2010
        Unprecedented Warming in Lake Tanganyika and its impact on humanity
        What an odd remark, coming from the person who is on record as saying has anyone happened to notice that this study is basically about fishing for sardines when the title of the paper is Late-twentieth-century warming in Lake Tanganyika unprecedented since AD 500. Why would Chris be the one to complain that someone else can't grasp what the central conclusion of the paper is despite it being in black and white? Chris has pointed out that the paper's central finding is entirely in keeping with much other research conducted elsewhere by other parties. Once again we're faced with what some folks claim are conclusions based on flawed data coincidentally resembling other independent findings. This resort to unknown, unstated defects as a counterargument is an yet another eerily familiar aspect to the paper at hand; we are expected to believe that all research in polyphony confirming what is expected as a result of predictions from physics is flawed yet produces congruent findings. How likely is that? This is becoming quite boring.
118793. johnd at 08:51 AM on 24 May 2010
        Unprecedented Warming in Lake Tanganyika and its impact on humanity
        chris at 08:28 AM, all I can suggest is that you contact the authors direct and complain that what you describe as secondary aspects, namely using the study to find any connection between declining primary productivity and rising temperatures, and the implications it has for the fisheries, has in your opinion taken the focus off what you consider the primary aspect, which appears to be of providing further proof of AGW. Perhaps they will issue a revision that better suits your interpretation of their work. Lets us all know what response you get. It appears as if here in this thread we see a classic example of the confusing of cause and effect, and the difficulty many have of relating their theoretical readings to the real world.
118794. chris at 08:46 AM on 24 May 2010
        Unprecedented Warming in Lake Tanganyika and its impact on humanity
        johnd at 06:46 AM on 24 May, 2010 That's really desperate johnd. If you've got a quibble with the data from the cores then define it - vague aspersions relating to some unspecified "certain graphs" and "perceived flaws" is scientifically meaningless. In any case the core proxy temperature data weren't spliced as is obvious from the Figure in the top article (and Figure 2 of the paper). The data from each core is displayed as a seperate line. In this case confidence in the equivalence of the cores results from the facts that: (i) the cores were from the same location. (ii) the analyzed proxies are identical. (iii) analysis of the core stratigraphy allowed a temporal alignment of the end of the long KH1 core with the start of the short MC1 core. (iv) the reconstructed temperatures during the regions of core overlap (top of KH1 with bottom MC1) are very similar. (v) the reconstructed productivity proxy (biogenic silica) during the regions of core overlap (top of KH1 with bottom MC1) are very similar. (vi) the reconstructed charcoal content during the regions of core overlap (top of KH1 with bottom MC1) are also similar.
118795. chris at 08:28 AM on 24 May 2010
        Unprecedented Warming in Lake Tanganyika and its impact on humanity
        johnd at 06:24 AM on 24 May, 2010 johnd, you're grasping at straws here. And why the efforts to shift the essential observations of this paper to secondary aspects? I noticed this paper before it was described on this site. It didn't really seem that big a deal to me. The data indicate that the very marked surface warming of Lake Tanganyika has likely produced temperatures higher than found for the last 1500 years, and that proxy estimates of primary productivity and temperature show an inverse relationship over this period (there's also an interesting mild warming temporally displaced from the Medieval Climate Anomaly that are observed in N. hemisphere temperature reonstructions). Those are the essential points aren't they? Otherwise the rest is interpretation. The high surface water temperatures are not really very surprising. These are well documented - e.g. see a very detailed analysis of Lake Tanganyika warming published last year [*]: [*] Verburg, P. and Hecky R. E. (2009) The physics of the warming of Lake Tanganyika by climate change Limnol. Oceanogr., 54, 2418–2430. abstract here Likewise Verburg and Hecky analyze primary productivity and show that this has decreased during the 20th century, and also conclude that warming may be contributing to the reduction in per-effort fish yields in the lake. Large lakes worldwide are warming in response to atmospheric radiative imbalance caused by enhanced greenhouse effect. [**] Similar data on 20th century warming and reduced primary productivity has been measured for Lake Malawi [***], etc. etc.: [**] Schneider, P., et al (2009), Satellite observations indicate rapid warming trend for lakes in California and Nevada Geophys. Res. Lett., 36, L22402 abstract here Vollmer, M. K. et al (2005) Deep-water warming trend in Lake Malawi, East Africa Limnol. Oceanogr. 50: 727–732 abstract here So the essential new data presented by Tierney et al (2010) is (i) to extend the direct measure of lake surface temperature through the last century back around another 1500 years by using paleoproxy temperature data, (ii) to document an inverse relationship between primary productivity and temperature during this period, and (ii) to highlight what looks like a mild warming period that seems temporally displaced from the N. hemisphere Medieval Climate Anomaly documented in other paleoanalyses. That's what the paper's about. It says so in the title and the abstract and the text and the Figures and their legends. The interpretation that the apparently unprecedented warming is due to global warming is pretty straightforward in the light of data from seas, lakes, land and atmosphere from 1000's of sources. It seems a straightforward interpretation that the warming "has potentially important implications for the Lake Tanganyika fishery".
118796. hadfield at 08:27 AM on 24 May 2010
        Robust warming of the global upper ocean
        In all these discussions, it's wise to remember that our ability to track ocean heat content changes to the accuracy shown in the figures (say 1-2 x 10^22 J) is very new. It results from a combination of two things: Argo and some very careful reanalysis of XBT data. As recently as 2005, the accepted time series of ocean heat content (Levitus et al 2005, Figure 1) showed a peak in OHC centred ~ 1980 and a drop of 5 x 10^22 J between 1980-1985. People were wondering why the OHC variability in climate models did not match the observations. It turns out (Levitus et al 2009, Figure 1) that this variability was over-estimated due to instrumental problems. The Lyman et al work (Figures 1 and 2 in this post) still shows quite large discrepancies between different analyses and I for one am sceptical that the data are accurate enough to support Trenberth's confident assertions about "missing heat" over a period as short as 5 years. Refs: Levitus, S.; Antonov, J.I.; Boyer, T.P. (2005). Warming of the world ocean, 1955-2003. Geophysical Research Letters 32(L02604): doi:10.1029/2004GL021592 Levitus, S.; Antonov, J.I.; Boyer, T.P.; Locarnini, R.A.; Garcia, H.E.; Mishonov, A.V. (2009). Global ocean heat content 1955–2008 in light of recently revealed instrumentation problems. Geophys. Res. Lett. 36.
118797. scaddenp at 08:19 AM on 24 May 2010
        Climate's changed before
        Roger - you cannot prove things in science; leave that to mathematics. What you can do is show that observations match the predictions of a theory. For a theory to be replaced, then you did to show either that it makes predictions that are not substantiated by observation within limitations of error, or, better, an alternative theory that explains the observation better. So far, there is a no competitor to the current theory of climate. You asked for empirical evidence,we showed it to you. You assert "he fact that there are well documented and general agreement that there have been previous warmings, such as the Holocene Maximum, the Minoan Warming, the Roman warming and the Medieval Warm Period, which are recorded in history as well as scientific proxies and the like, make CO2 as the root cause of global warming even less likely." This is not true. You plug the known forcings into exactly the same theory of climate and you get the observed warmings within the error for estimating both climate and forcings. Are you aware of the Mann 2009 paper on MCA by the way? You statements on MWP make me suspect otherwise. What we can also observe is that the forcings operating in these past periods are not operating today or even in reverse (eg Milankhovich). Now it is possible that there is some undiscovered energy transfer going on that has somehow eluded us - but that is not the way to bet in a very high stakes game. The empirical observations give us confidence that there is a GHG forcing of the right magnitude to induce current warming. Furthermore, the observations of the upper stratosphere cooling are very hard to reconcile with any other forcing.
118798. JMurphy at 08:17 AM on 24 May 2010
        Volcanoes emit more CO2 than humans
        Eric (skeptic), we should be grateful that the EU has made such cuts, otherwise the increase in CO2 would be even greater now with the volcanoes added input. Just think how worse things would be if the EU hadn't made those cuts - especially if the volcano were to continuing erupting such amounts for a full year, which is unlikely.
118799. Riccardo at 07:24 AM on 24 May 2010
        Has the greenhouse effect been falsified?
        Berényi Péter, while i can see logic of the sequence in the book, i still can not understand your point. Why did you show that sequence of graphs? The extreme -90 °C case in winter in Antarctica (presumably Vostok), what has to do with fig. 1 here taken at Barrow at a temperature of about 0 °C? Leave the "cooling effect" aside. Remember that 20 Km above the surface in Antarctica is well inside the stratosphere and temperature increases with altidude there. What you improperly call "cooling effect" is just emission from the stratosphere at a higher temperature than the ground. It's always there.
118800. Doug Bostrom at 07:00 AM on 24 May 2010
        Unprecedented Warming in Lake Tanganyika and its impact on humanity
        As a point of reference, perhaps it would be useful to have the abstract available here directly: Late-twentieth-century warming in Lake Tanganyika unprecedented since AD 500 Jessica E. Tierney1, Marc T. Mayes1,2, Natacha Meyer1, Christopher Johnson3,4, Peter W. Swarzenski5, Andrew S. Cohen3 & James M. Russell1 Instrumental observations suggest that Lake Tanganyika, the largest rift lake in East Africa, has become warmer, increasingly stratified and less productive over the past 90 years (refs 1,2). These trends have been attributed to anthropogenic climate change. However, it remains unclear whether the decrease in productivity is linked to the temperature rise3, 4, and whether the twentieth-century trends are anomalous within the context of longer-term variability. Here, we use the TEX86 temperature proxy, the weight per cent of biogenic silica and charcoal abundance from Lake Tanganyika sediment cores to reconstruct lake-surface temperature, productivity and regional wildfire frequency, respectively, for the past 1,500 years. We detect a negative correlation between lake-surface temperature and primary productivity, and our estimates of fire frequency, and hence humidity, preclude decreased nutrient input through runoff as a cause for observed periods of low productivity. We suggest that, throughout the past 1,500 years, rising lake-surface temperatures increased the stratification of the lake water column, preventing nutrient recharge from below and limiting primary productivity. Our records indicate that changes in the temperature of Lake Tanganyika in the past few decades exceed previous natural variability. We conclude that these unprecedented temperatures and a corresponding decrease in productivity can be attributed to anthropogenic global warming, with potentially important implications for the Lake Tanganyika fishery. As a layman, if I concur w/johnd on any point it's probably down to conclusions beyond the temperature signal indicated as the primary result of the paper but frankly my opinion on that is not worth much. On a tangential note, the discussion here is exemplary of how much friction is introduced when an article cannot be read in its entirety because of proprietary concerns, in this case the need for Nature to balance its books so it may continue to publish.

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