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Comments 118801 to 118850:

118801. johnd at 06:46 AM on 24 May 2010
        Unprecedented Warming in Lake Tanganyika and its impact on humanity
        Something that should have been raised, but wasn't, is the matter of the splicing of the data obtained from the core samples together. Recently the matter of splicing temperature data in graphs was the subject of intense scrutiny and debate with certain graphs rejected because of some perceived flaw. So what is different here? The only difference perhaps is that there is no other benchmarks that can validate or otherwise the appropriateness of splicing this particular set of data. Where are all those posters critical of the temperature graphs? Any comments that remain consistent with similar previous critical analysis?
118802. johnd at 06:24 AM on 24 May 2010
        Unprecedented Warming in Lake Tanganyika and its impact on humanity
        mike at 17:51 PM, perhaps everyone needs to clear all preconceptions and agendas from their minds and get back to the basics by reading past the headlines for a change and locating what are the central issues addressed by both the study and this thread. If you haven't read the lead post of this thread in it's entirety there were two, and only two questions posed which should have provided a clue to those alert enough as to what the central issue was. The questions are 1. "What effect does temperature have on the lake's sardine population?" 2. "How does temperature affect primary productivity?" Sardines are mentioned four times, primary productivity eight times. Additionally the abstract for the article published in Nature concludes with the following statement, "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." In addition the study did the following, It measured evidence of historic productivity. It attempted to correlate recent temperatures with recent productivity. Finally it reached conclusions about future fishery productivity, of which sardines are the primary catch. What this thread makes painfully obvious is how easy it is for some people to be led simply by placing a notion in their mind so that everything after that then becomes related to that notion and used to further support what they now believe, even if it has to be distorted to do so. Before I go on perhaps you should go back to the lead post posted by John Cook, plus read the article in question through to the conclusions, or failing that, the abstract just to clarify what were the questions that the study set out to answer and what were the conclusions reached. Having said all that, with your background you probably appreciate how big an area the lake covers, about 700km by 50km, and just how variable everything could be over such a vast area. There is quite a bit of literature available from previous studies, and as one might expect, some of them note how highly variable many of the relevant factors and indicators are. Lake surface temperatures in different locations can vary by 4 degrees at a given time, climatic conditions vary so that different winds and currents mean local conditions vary across and around the lake, and so too do the fish catches across the different regions of the lake. Given the study was based on collecting samples of BSi which is considered an indicator of primary productivity, and there is information that primary productivity from the lake is not only declining but highly variable across the regions, whilst data indicating such may be available for current and recent times, core sampling has to be undertaken to obtain historical data. This brings us back to the point I have been making all along, I have serious doubts that a single core sample can represent all the variables that form part of subject being studied, namely primary productivity, in particular sardines, as so clearly stated in the lead post of this thread. With you background I imagine that you are aware of how often it has happened, often famously or more often, infamously, where on the basis of a single sample, major new discoveries have been announced only to fizzle out when it was found that the single sample was anything but representative. Perhaps you have heard of Bre-X where after the initial euphoria of a major discovery failed to be sustained, those involved then worked hard to ensure the evidence being collected matched the expectations created by the initial discovery, the similarity not lost when some of the work on tree proxy reconstructions was closely scrutinised.
118803. Berényi Péter at 05:51 AM on 24 May 2010
        Has the greenhouse effect been falsified?
        #52 Riccardo at 04:05 AM on 24 May, 2010 could you be so kind to provide the figure captions Unfortunately I don't have the book itself, just web references (publisher's site). There are some excerpts from first edition along with all the figures. But Fig 8.3 a-c is rather self explanatory. The effect of really low specific humidity can be seen at the low frequency end of Fig 8.3 b (Antarctica). I think Fig 8.2 (Barrow, Alaska) shown as Fig 1 in the post does not have extreme low humidity after all. Fig 1 a (20 km looking down) may lack vapor fingerprint below 600 cm^-1, but Fig 1 b (surface looking up) has it. With really low vapor contents it would be a partial see-through in this frequency range to 2.7 K space above (as it is at the Antarctic ice sheet during winter). On top of that the rather high surface temperature (268 K) indicates the shot was not made in winter. Also, note how CO₂ has a cooling effect in Antarctic winter and to a lesser extent for deep convective cloud tops at the Tropics (Fig 8.3 c, lower graph). It is worth considering the highly variable contribution from water vapor as well, even if none of the graphs shows anything below 400 cm^-1 in spite of the significant (wet) action happening there.
118804. Doug Bostrom at 05:46 AM on 24 May 2010
        Robust warming of the global upper ocean
        RSVP while sadly I do not have the skill or background necessary to provide a proper answer, I imagine that if the upper ocean is unable to convey heat to the lower ocean with sufficient speed, the upper ocean will indeed become less effective at mopping up heat from the atmosphere, so we could then expect to see the atmosphere begin to warm more rapidly. Veering off into complete speculation, this is sort of consistent with what we see and even fits with Berényi's assertion that the ocean is taking up less heat of late. But I don't really know enough about what I'm talking about, so take it with a salt dome.
118805. Doug Bostrom at 05:35 AM on 24 May 2010
        Robust warming of the global upper ocean
        Berényi I hear what you're saying about XBT versus ARGO data but I have to say I find it hard to imagine that the total (and rather astoundingly large) difference in heat content between the left and right end of the graph is all down to instrumentation error. That would imply that the instrumentation is entirely worthless, which I believe would be a fairly controversial assertion and probably very hard to defend in detail.
118806. gp2 at 05:10 AM on 24 May 2010
        Robust warming of the global upper ocean
        According to Lyman et al. 2010 clearly there is no OHC decrease in the last 6 years, trenberth paper is available here.
118807. Riccardo at 04:57 AM on 24 May 2010
        Robust warming of the global upper ocean
        Jeff T, the red line is the trend from 1993 while the comparison with the Argo 0-2000 data (blu line, 0.54 W/m2) has to be made starting from 2003, in which case the trend is down to about 0.23 W/m2.
118808. Eric (skeptic) at 04:50 AM on 24 May 2010
        Volcanoes emit more CO2 than humans
        It is useful to compare the volcano in iceland and its 150-300 ktons per day to the EU cuts. According to this article, http://europa.eu/rapid/pressReleasesAction.do?reference=IP/09/794 the EU cut about 174 ktons per day in 2008. The Icelandic volcano emits about 150-300 ktons per day, a comparable amount. Of course the volcano will stop emitting at some point, but for now it is a valid skeptical talking point to say that the volcano undoes the EU cuts.
118809. Jeff T at 04:24 AM on 24 May 2010
        Robust warming of the global upper ocean
        This statement near the end of the post confuses me, "Note that the blue trend is greater than the black line over the same period. This means that more heat is accumulating at greater depths than 700 metres." The deep data (blue line in Figure 3) have a SMALLER slope than the shallow data (red). It's the slope that matters, isn't it?
118810. Mal Adapted at 04:21 AM on 24 May 2010
        Unprecedented Warming in Lake Tanganyika and its impact on humanity
        Si:

        Again why the ad hom attacks? (and yes I do lack the simple comprehension why some regular posters on this site sneer and belittle others - it is why I read this blog so seldom)

        Our host has deleted both of our most recent comments, no doubt because they violated the comments policy -- sorry John, I'll be more careful. Your reaction to perceived attacks is further evidence that you're not acquainted with how science is actually done. In the community of scientific peers, debate can be pretty rough-and-tumble, and that's a good thing. This piece (h/t Hank Roberts) by a former member of that community lays it out succinctly:

        Science doesn’t work despite scientists being asses. Science works, to at least some extent, because scientists are asses. Bickering and backstabbing are essential elements of the process.

        The point of my original comment is that if you want to challenge the AGW consensus, you need to follow the same long, arduous process as the scientists who contributed to it. There are easier ways to make a living, believe me. I don't think it's beyond your abilities, but until you've covered all the ground the experts have, your sense of your own competence is illusory. That's not an attack, that's just sincere advice.
118811. Riccardo at 04:05 AM on 24 May 2010
        Has the greenhouse effect been falsified?
        Berényi Péter, could you be so kind to provide the figure captions or give the details yourself?
118812. e at 03:46 AM on 24 May 2010
        Unprecedented Warming in Lake Tanganyika and its impact on humanity
        RSVP, I think your point was addressed in the course of discussion, though perhaps not directly. Nobody here is claiming that this single data point proves or disproves global warming. It is just another data point consistent with the so-called "hockey team" global reconstructions. It is the summation of this data point and many many others that makes the case for global warming, not any one data point on its own. The point is not that local conditions should be ignored, but that they must weighed in summation with other local conditions across the globe.
118813. RSVP at 03:03 AM on 24 May 2010
        Robust warming of the global upper ocean
        As oceans warm over time, for the "same" air temperature, oceans should warm less as per convective heat transfer law. Would this not constitute negative feedback?
118814. RSVP at 02:58 AM on 24 May 2010
        Unprecedented Warming in Lake Tanganyika and its impact on humanity
        sorry, not Artic, Antartic
118815. RSVP at 02:57 AM on 24 May 2010
        Unprecedented Warming in Lake Tanganyika and its impact on humanity
        chris. you say, "The observation is that the Lake Tanganyika surface has warmed very considerably especially in the last 50 years, and is likely warmer than it has been for 1500 years. The warming of the last 50 years has been directly measured and is in line with the wider understanding of enhanced greenhouse-induced warming both locally and more widely." I asked a fair question in an earlier post relative to what you are stating here in point six. That is, why does it seem appropriate to make a case for global warming about a geographically localized condition? By the way, the question is not directed necessarily to you. It is actually rhetorical in that it refers to what I thought was rule number one around here, not to use local conditions to make a case about global warming. In fact, just the opposite was true when it was pointed out that there were surface waters in the Artic that were actually cooler, this data being discounted as actually proof of global warming for other convoluted reasons. I would add that where I made the comment earlier, it was done in tandem with another remark, and as I have found many times in the past, those that take up points with me typically choose what appears to be the easier issue almost as if to tactically distract readers from what might be embarrassing or controversion.
118816. Albatross at 02:38 AM on 24 May 2010
        Unprecedented Warming in Lake Tanganyika and its impact on humanity
        Chris @152, "It's simply impossible to discuss straightforward issues of science with individuals that use ignorance as a debating point, adopt a null hypothesis that everything they think of that might be a problem is a problem, and consider that the point of reading a scientific paper is to attempt to trash it (by misrepresentation if necessary)." I would second that, especially the last portion of the sentence. You really did hit the nail on the head there. As for the rest of your post. Thanks. Thanks too for bringing the thread back on track again-- you make some excellent points. Si @154, two words "cumulative impacts". And please don't spam this thread by desperately throwing out there every contrarian speaking point which has long been debunked.
118817. Berényi Péter at 02:16 AM on 24 May 2010
        Has the greenhouse effect been falsified?
        #50 sylas at 02:23 AM on 23 May, 2010 please be assured that I am not deliberately distorting things I have never told you would do such a thing, not even thought about it. If it gave an impression like that I am sorry. Figure 1 comes from a textbook (it is Fig 8.2 there). A First Course In Atmospheric Radiation (2nd Ed.) By Grant W. Petty 460 pp. (paperback) Sundog Publishing, Madison, Wisconsin Publication Date: March 2006 ISBN-10: 0-9729033-1-3 ISBN-13: 978-0-9729033-1-8 Unfortunately we have seen more than one error in textbooks. Of course the arctic air could be extremely dry then and there. We may never know since neither date & exact location of measurement is specified, nor arctic window (long wave, low wave number) frequencies are included in the upwelling IR graph. Otherwise the sheer mass of air above sea level also absorbs some window radiation. Anyway, it is always better to understand in detail what you see than not to. Fig 8.3 a-b-c-d of the same book are also enlightening.
118818. chris at 01:48 AM on 24 May 2010
        Unprecedented Warming in Lake Tanganyika and its impact on humanity
        Oh well, this illustrates why science pseudoskeptics organise their own climate "conference" and real scientists don't go. It's simply impossible to discuss straightforward issues of science with individuals that use ignorance as a debating point, adopt a null hypothesis that everything they think of that might be a problem is a problem, and consider that the point of reading a scientific paper is to attempt to trash it (by misrepresentation if necessary). Relating to some of the stuff that’s been thrown at the paper on this thread, it isn't difficult for a non-expert to quite easily establish the following: ONE: the paper isn't about sardines. "Primary productivity" refers to productivity at the bottom of the food chain and in marine/lake environments usually relates to the photosynthetic fixing of CO2 which is the primary source of biological productivity at all levels of the food chain. In other words assessment of primary productivity in oceans and lakes usually relates to algae. It doesn't mean sardines! TWO: Despite assertions that the proxy temperature record isn't calibrated against the lakes surface temperature, in fact the proxy data that overlaps (top of the core) contemporary direct measurements were cross correlated with direct lake surface temperatures (at Kayla and Mpulunga; see Figure 2 of Tierney et al, 2010). In addition the temperature proxy was calibrated with a large amount of additional data that relates lake surface temperatures to the TEX proxy temperatures (see Supplement of Tierney et al, 2010). Even if the top of the TEX data wasn't extensively calibrated (it was) or the core proxy temperatures matched with direct lake surface temperatures (it was) the interpretation that current lake temperatures are the warmest in 1500 years is independent of any uncertainties in calibrations, or offsets relative to current temperatures. THREE: Hydrothermal vents. Skepticstudent linked to a paper about hydrothermal vents in lake Tanganyika but failed to do the obvious assessment of whether these were near the coring site. Hydrothermal vents are found in the Uvira fault region at or near the N end of the lake (in the waters near Pemba and Cape Banza). Inspection of a map indicates that these are 300 km or more from the coring site. FOUR: Hydrothermal vents. Significant warming from hydrothermal vents would yield a distinctive pattern of warming in the water column. Sampling of the water column and multiple sites throughout the lake indicates that there is no significant contribution from bottom warming and that the thermal pattern of water column is as expected from surface warming. FIVE: non-representativeness of a single core. Similar arguments apply to Antarctic cores. Single cores give data that are representative of particular spatial regime as long as an appropriate proxy is used. Thus a single core can give good insight into CO2 levels worldwide since CO2 levels are well averaged globally on the timescales of core resolution. Temperature proxies also give good representation of a wider spatial extent since it is well known that temporally-averaged temperature variations are correlated across significant distances (up to 1200 km). In this particular case (Tierney et al, 2010) analysis of lake surface temperatures and temperature profies through the water column indicate that single sites within Lake Tanganyika are likely to be more widely representative (see Figure just above). SIX: The warming not due to man-made global warming. Since the site chosen for coring was in an isolated area with little human population, little deforestation or agriculture (which could impact on nutrient loading by runoff), there is little evidence that local direct human impacts affect the analyses. The observation is that the Lake Tanganyika surface has warmed very considerably especially in the last 50 years, and is likely warmer than it has been for 1500 years. The warming of the last 50 years has been directly measured and is in line with the wider understanding of enhanced greenhouse-induced warming both locally and more widely. The attribution of the warming to anthropogenic global warming is a pretty reasonable one in the context of what we know. SEVEN: General point. This paper seems like a pretty good analysis of paleoproxies for lake surface temperatures, primary productivity (and charcoal deposition as a proxy for local forest fires). However (and with greatest respect to Dr. Tierney and her coauthors) its interpretations and conclusions are a small input to our broad understanding of the Earth response to human enhancement of the grrenhouse effect. It really isn't worth a frenzy of attempted trashing!
118819. Riccardo at 01:43 AM on 24 May 2010
        Robust warming of the global upper ocean
        Berényi Péter, "It is only the last 6 years when OHC in the upper 700 m of oceans is measured properly. It is decreasing" Apparently not.
118820. Berényi Péter at 00:39 AM on 24 May 2010
        Robust warming of the global upper ocean
        #4 Marcel Bökstedt at 21:32 PM on 23 May, 2010 Is there a reason for that the uncertainty due to choice of correction is small in the beginning and the end of the period (around 1996 and 2006), and bigger in the middle (around 2000) - that looks strange to me? Yes. Instrumentation has changed a lot in this time interval. There is also a gap between 1996 and 2002 when old (MBT/XBT) systems were all but abandoned and ARGO was not deployed en masse yet. The huge and abrupt increase in OHC at the end of this period must be an artifact due to intercalibration problems and lack of data. It is also inconsistent with satellite radiation budget measurements. It is only the last 6 years when OHC in the upper 700 m of oceans is measured properly. It is decreasing. Below that level even recent data are unreliable, because ARGO floats in the tropics initially have not worked according to design. The guys didn't dare to let them go down to 2000 m for they would never come back to the surface in waters warm enough.
118821. Marcel Bökstedt at 22:37 PM on 23 May 2010
        Robust warming of the global upper ocean
        Bérenyi Péter> The papers in question here discuss the trend in ocean heat content up to 2008. As far as I can see, the corrections you mention cannot have much influence on this.
118822. Marcel Bökstedt at 21:32 PM on 23 May 2010
        Robust warming of the global upper ocean
        These papers are clearly important, but not so easy to read for a non-expert like me. I'll try to state what I get out of the Lyman paper, in the hope that someone can correct my misunderstanings. First a very very stupid question, but google did not help me, and maybe I'm not the only one who does not know: What precisely does the technical term "climatology" mean in contexts like "We estimate climatological uncertainties (Fig. 3, magenta line) arising from Argo versus pre-Argo sampling from pairs of curves using the same mapping routine and XBT corrections but different baseline climatologies (Fig. 2, solid vs. dashed lines)." But more importantly, what exactly are Lyman et al doing? They trust data from the new Argo floats, so that the main problem they want to adress is how to interpret the older data from the XBT sinking devices. There has been a number of attempts to translate these data into ocean heat content data. These attempts don't agree with each other (fig 1 above), and the paper is trying to reconcile the attempts. According to this study, we can break up the differences between the different published ocean heat content reconstructions into several components. I believe that the main argument is that by analysing the uncertainty in each of these component individually and adding, the uncertainty in the total ocean heat content estimate gets smaller. The main components are: Differences in XBT data sets, differences in climatology, differences in method of XBT bias corrections. The first step is to recompute the published estimates for ocean heat content, using the published algorithms for bias correction, but using the same standard dataset or the same standard climatology (which at least means choosing the same period for computing the temperature baseline, but presumably more than this). In figure 2 above, the results are compared to the original estimates, and to each other. The green line corresponds to one method of bias correction as originally published, the green dotted line to the same bias correction but with the standard climatology, the green dotted line again with the same bias correction, but with the standard raw dataset. Using the same dataset or the same climatology brings the curves closer, but they are still far from identical. The end result is that the biggest uncertainty in the estimate of ocean heat content comes from the choice of method for bias correction. I believe that they consider the published methods as having equal value, and compute a mean and standard deviation from the set of these methods. This mean is then the basis for their estimate of ocean heat content. A few points I don't understand: What is the uncertainty due to "mapping"? Is there a reason for that the uncertainty due to choice of correction is small in the beginning and the end of the period (around 1996 and 2006), and bigger in the middle (around 2000) - that looks strange to me?
118823. Mythago at 21:09 PM on 23 May 2010
        The significance of the CO2 lag
        Many thanks to 'Ned' and Michael Sweet for answering my question about the CO2 relationship between the atmosphere and the ocean. I now understand. Simple answer that I should have known was 'equilibrium' or 'establishing a balance' between the ocean and the atmosphere, (to put it another way). Thanks gents for the assistance. Very useful explanation and one I can understand easily.
118824. Berényi Péter at 20:24 PM on 23 May 2010
        Robust warming of the global upper ocean
        #2 tobyjoyce at 17:57 PM on 23 May, 2010 The link to Lyman(2010) needs to be fixed It must be this one: Letter Nature 465, 334-337 (20 May 2010) | doi:10.1038/nature09043; Received 8 December 2009; Accepted 22 March 2010 Robust warming of the global upper ocean John M. Lyman, Simon A. Good, Viktor V. Gouretski, Masayoshi Ishii, Gregory C. Johnson, Matthew D. Palmer, Doug M. Smith & Josh K. Willis However, before delving into the question deeper I would like to know the actual reason behind the downward modification of OHC trend for the last couple of years at NODC occuring on Wed, 20-Jan-2010 22:14 UTC. It is undocumented.
118825. RSVP at 19:36 PM on 23 May 2010
        Unprecedented Warming in Lake Tanganyika and its impact on humanity
        Albatros quotes: "...But there is no evidence for increased deepwater volcanic activity in the lake in the 20th century. In 1971, a survey team found that the rate of geothermal heat flux in Tanganyika was 0.04 watts per meters squared, close to the global average (Degens et al., 1971, Naturwissenschaften). ..." If volcanic activity is perfectly constant, but the lake level decreases, the temperature just might be affected after a while. Now the difficulty arises... is this due to the volcanic activity, global warming or maybe just a local climate change?
118826. Riccardo at 19:23 PM on 23 May 2010
        It's the sun
        Friend, the microwave power emitted by the sun is many orders of magnitude lower the the IR or visible emission. I'd not expect any significant effect.
118827. Riccardo at 19:19 PM on 23 May 2010
        Arctic sea ice has recovered
        Erik, fig. 2 above is not a forecast but a model calculation of ice volume, where the measured relevant parameters are fed in. Section 2 of the paper describes the model, the first paragraph of section 3 describe how they use it in forecast mode.
118828. Si at 18:55 PM on 23 May 2010
        There is no consensus
        Doug, it is a plea for more funding. "It calls for a new era of climate change science where an emphasis is placed on "fundamental, use-inspired" research,"
118829. tobyjoyce at 17:57 PM on 23 May 2010
        Robust warming of the global upper ocean
        P.s. The link to Lyman(2010) needs to be fixed!
        Response: Fixed, thanks for pointing that out.
118830. tobyjoyce at 17:55 PM on 23 May 2010
        Robust warming of the global upper ocean
        I would like just to check the meaning of the word "robust" in this context. In statistics, a "robust estimate" is one that is not affected by small departures from model assumptions. Does the phrase "robust warming trend" have the same meaning here?
118831. mike at 17:51 PM on 23 May 2010
        Unprecedented Warming in Lake Tanganyika and its impact on humanity
        63 johnd at 08:34 AM on 22 May, 2010 "Whether taking simple surface sediment cores or cores from deep below in the search for natural resources, there is a strict regime on what is required to satisfy firstly those who will decide whether to proceed further or not, and an even tighter requirement for it to become part of a bankable feasibility study, and then even tighter beyond that." johnd- As a research geologist with some small amount of experience in mineral exploration, I think your criticisms are off base. In the world of publicly-funded science, "those who will decide whether to proceed further or not" and for work to "become part of a bankable feasibility study" are the peer reviewers of the journal where the work is published. The fact that Dr Tierney's paper appears in Nature Geoscience - a very prestigious journal with a low acceptance rate - means that your quality-control concerns would have been met more than adequately in the review process. Your continued questioning in this regard is as inappropriate as would mine be of your professional work. The difference of course is that your proprietary output is protected from comment by the ignorant whereas the work of those who publish in the peer-reviewed literature is available to all to pick over.
118832. Phila at 17:25 PM on 23 May 2010
        Unprecedented Warming in Lake Tanganyika and its impact on humanity
        #120 Frogstar "As a (skeptical) scientist, I am here because the topics under discussion are being used in a semi-technical geopolitical debate that involves subjects very dear to my heart (life, death, money, taxes, etc)." The policy implications are well worth discussing and there's plenty of room for honest disagreement. It's a serious subject, and ideally, we'd all be having an serious conversation about it. Unfortunately, that discussion is largely being postponed so that we can argue over whether CO2 is actually a greenhouse gas, whether Jessica Tierney actually knows how to conduct research, or what have you. "The kinetics in that lab taught me a lot about waiting to see if measurements bore out predictions and, when they didn't, it was a learning opportunity." That's a reasonable approach in many situations. This situation is a bit trickier, obviously, because the prognosis gets worse as we wait and there are no do-overs, as far as we know. The better analogy here would be to medicine: With some conditions, you can wait for measurements to bear out predictions. With others, doing so would be...well, let's just say "unwise."
118833. Doug Bostrom at 16:40 PM on 23 May 2010
        Unprecedented Warming in Lake Tanganyika and its impact on humanity
        Presumably frogster is referring to such serious and enlightening remarks from so-called skeptics as: One tree does not a hockey stick make ;-) or LOL. Has anyone happened to notice that this study is basically about fishing for sardines? Regarding speaking to truckers, frogster, I think it would not be too difficult to show how Willis' critique of Tierney's paper is not aimed at the side of the correct barn. "Your oil pressure gauge is wrong, you know that it reads 50psi when it really is measuring 60psi. If the reading on the gauge drops to 40psi you know you've got a loss of oil pressure, even if you know the reading is 'wrong'." Not complicated.
118834. Albatross at 16:21 PM on 23 May 2010
        Unprecedented Warming in Lake Tanganyika and its impact on humanity
        thefrogstar @120 "climate science thought it could 'run with the big boys' yet still go on 'providing weather forecasts'." There is so much wrong that statement-- I'm not sure whether your erroneous comparsion with weather forecasts was intentional or not. Anyhow, I'll leave it there. As for your claim about some of the points being raised by contrians here being "valid". I strongly disagree, and that is exactly why I and others are getting frustrated. Do you not see how arrogant and rude it is by some here to presume to know more than the people (e.g., Dr. Tierney and her colleagues) who have worked so hard on this, those who have researched the topic at hand (i.e., literature review), wrote the proposal, invested the time and effort to collect the data, processed it, analysed it, checked the numbers, written it up, gone through several iterations, and then finally gone through peer review (a very humbling and exhausting experience in most cases), only to have some people posting on an internet blog (who are not even qualified or experienced in the field and who have not taken the time and effort to understand the problem in the first place)cavalierly dismiss it as sardine research. And worse yet, doing so not using rational and informed scientific critique and methods, but essentially taking cheap shots. I sense no inclination whatsoever from certain contrarians to learn form this paper, or other climate papers, or to concede when they have been shown to be wrong. Does that not tell you something or concern you? Moreover, most of the criticisms raised here have been addressed by the authors, and people who have published on the subject prior to this study (this study does not stand in isolation, it is part of a much bigger picture of scientific understanding), yet the contrarians it seems could not be bothered to first do the leg work to determine whether or not their "concerns" had been addressed before making condescending remarks. This has happened repeatedly in recent years in the field of climate science and related disciplines, and to be candid, it is getting incredibly tiresome. I'll agree with you that the IPCC has done a relatively poor job at communicating the science. That said, they are, believe it or not, reliant on the volunteer work of hundreds of scientists and have very few full time staff. They do not have a well-oiled, experienced and politically savvy PR team. Anyhow, let us hope that they are provided the means required to communicate the science and the gravity of this situation in AR5. And frogstar, the hubris I am seeing (on an increasing scale) is coming from the contrarians and "skeptics". I am pretty highly qualified in my field, but I don't not presume to know more, or feel inclined to be contrary or question the science of an oncologist, for example. Additionally, I acccept that they are highly trained, experienced and professional, and that it would be incredibly arrogant and disrespectful (paranoid even?) of me to feel obligated to openly question their work simply because they were the bearer of bad news or news that their findings did not sit well with me. And, in the event I did elect to attack or question their research after Googling for a few days, I would not be offended (or surprised) if they set me straight, were rather snarky or accused me of hubris even if I do happen to have post graduate degree/s in another unrelated field.
118835. thefrogstar at 15:20 PM on 23 May 2010
        Unprecedented Warming in Lake Tanganyika and its impact on humanity
        Phila #118, The science on these threads can, and will, progress, irrespective of whether skeptics arguments turn out to be correct or not. As a (skeptical) scientist, I am here because the topics under discussion are being used in a semi-technical geopolitical debate that involves subjects very dear to my heart (life, death, money, taxes, etc). That's inevitably going to bring more scrutiny, from people at all levels of scientific education and competence. Yes, it's uncomfortable. My adviser used to tell us (his research group) that if we "couldn't explain what we did, and why it was important, to a truck driver in a honky-tonk bar in Texas, and why they should be paying for it", then we should ask ourselves some serious questions. Frankly, what I read on this particular thread, is a bunch of people being quite rude and disparaging towards (a few) other people who are clearly scientifically competent and seem to be raising valid points. That approach is not going to get very far with the truck drivers. Without being (too) rude, I sometimes wonder if climate science thought it could 'run with the big boys' yet still go on 'providing weather forecasts'. Another thing my supervisor told us is "that we're a kinetics lab". The kinetics in that lab taught me a lot about waiting to see if measurements bore out predictions and, when they didn't, it was a learning opportunity. Unfortunately climate science doesn't work on the same time scale as most other sciences, and the hubris seems to be commensurately greater.
118836. Friend at 12:55 PM on 23 May 2010
        It's the sun
        Isn't it possible that the Sun is causing an increase in temperature of the core of the earth by way of radiation that passes harmlessly through the atmosphere and crust much like a microwave oven? Or is this just impossible? thanks
118837. Doug Bostrom at 12:17 PM on 23 May 2010
        Climate's changed before
        Roger, what's to discuss? The National Academy of Sciences says anthropogenic warming is a fact, you say it's not and you're quite unprepared to accept otherwise. I'm a bystander to your argument with the NAS but I have to say, I attach more weight to their conclusion and not yours. Are you surprised, that I'd have to give more credit to the NAS and their conclusion based on a veritable mountain of evidence, as opposed to your personal opinion supported by a Youtube video? What an extraordinary conversation. I've participated in many such yet they still leave my head spinning. Either one must leave the merry-go-round filled with folks who show every sign of technical psychosis or one must jump on and join the endless revolution of repetitions.
118838. Rogerthesurf at 11:50 AM on 23 May 2010
        Climate's changed before
        Doug, Have done, However 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? And it might be news to you but "anthropogenic warming" is not considered to be fact, even in IPCC reports and there is an increasing body of opinion that support what I am questioning. But most importantly, lets not forget this conversation is about whether this blog addresses the question "What does past climate change tell us about global warming?" and I am maintaining that it skirts around the real issue which is what I am raising here. Cheers Roger
118839. Doug Bostrom at 11:30 AM on 23 May 2010
        Unprecedented Warming in Lake Tanganyika and its impact on humanity
        You're of course entitled to your opinion that the paper under discussion here is "primarily about sardine production" when sardines are not mentioned in the title. I'm uncomfortably prepared to concede that the paper would possibly have been better focused if it had confined itself to paleotemperature reconstruction but technically speaking I don't have the background to say that. For my part-- concerned as I am with climate change-- the significance of the paper lies in what its title says. Probably needless to say, but the reason I found my way here was because of climate problems, not a shortage of sardines. At the end of the day, your argument still consists of "I doubt it." But there's no such thing as a last word in a venue such as this so I'm going to ignore what you have to say next about this unless you veer off in some other direction.
118840. Phila at 11:23 AM on 23 May 2010
        Unprecedented Warming in Lake Tanganyika and its impact on humanity
        #101 "e and Phila, 94 and 95. I think there are rather more skeptical climate scientists than you realise. - Spencer, Michaels, Christy" Yes, there are some skeptical climate scientists out there, and they've been making their views known for years, as they should. I fail to see what this has to do with people who lack any relevant expertise casually accusing working scientists of not understanding their own fields. How does such behavior make science "more robust"? More to the point, how could science ever progress if it were obliged to cater to that odd combination of arrogance and ignorance? Look, I'd love to revolutionize evolutionary biology, or any other field...but realistically, what are the chances I'm going to do that without educating myself to at least the level of a grad student, not just in the subject itself but also in the nuts and bolts of scientific practice and discourse? The skeptical scientists you've named have so far failed to convince very many of their colleagues that they're right and everyone else is wrong. But they do have credentials and they've more or less followed the rules of the game. As such, their contributions are valuable even if they're incorrect. But too many amateur "skeptical" arguments -- including some of the ones on this thread -- fall under the category of "not even wrong." We agree that it's healthy to have people get more interested in and involved with science. But we seem to disagree about the amount of time, effort, and humility it takes to get good at it. As I see it, no one deserves an 'A' just for showing up.
118841. johnd at 11:19 AM on 23 May 2010
        Unprecedented Warming in Lake Tanganyika and its impact on humanity
        michael sweet at 10:47 AM, it would be appreciated if you would stop assigning your own meanings to my posts which you tend to twist into a supposed insult against someone else. It is not what reflects on me that should concern you. If I'm not mistaken, one of the studies I referred to earlier on a couple of occasions was part of the Nyanza Project, there are numerous such papers available. Variability was a matter that seemed to pop up quite frequently which is what the focus of my posts have been on, and whether or not is has been accommodated or allowed for.
118842. Doug Bostrom at 11:12 AM on 23 May 2010
        Climate's changed before
        Roger, you should add this to your blog because it speaks to the weight of your opinion on this subject: 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. That's from the National Academy of Sciences. You can find the press release for this just-released report as well as links to the report itself here. What is this "National Academy of Sciences"? You can learn about it here. It's sort of like the UK's Royal Society but with the brand of USA on it. The basic point is, anthropogenic warming is considered to be fact, uncontroversially so in terms of scientific understanding. If you dig into the science you'll find past changes of climate playing the role of evidence in support of this fact.
118843. johnd at 11:04 AM on 23 May 2010
        Unprecedented Warming in Lake Tanganyika and its impact on humanity
        doug_bostrom at 10:19 AM, apparently it is not only me that you consider to suffer from cognitive disconnect. In case you haven't read to the end of the article abstract as yet, or the lead at the top of this thread. Here is the last sentence from the abstract which I think I already had referred you to earlier. "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." Note that the word productivity is mentioned repeatedly. It measured evidence of historic productivity. It attempted to correlate recent temperatures with recent productivity. Finally it reached conclusions about future fishery productivity, of which sardines are the primary catch. In addition, carefully read the post which leads this thread and look at the only two questions John posed. I imagine they were asked as part of initiating the direction of the topic for discussion. "What effect does temperature have on the lake's sardine population?" "How does temperature affect primary productivity?"
118844. Eric (skeptic) at 11:00 AM on 23 May 2010
        Arctic sea ice has recovered
        

        The volume chart above relies on the PIOMAS model. The model seems fine for predicting the summer minimum near the beginning of the melt season. See for example, the predictions for 2008: http://psc.apl.washington.edu/IDAO/seasonal_outlook.html Here they made an essentially correct prediction of substantially higher ice in Sept 2008 than Sept 2007. During the previous winter (2007-2008) they wrote a paper predicting the 2008 summer ice extent: LINK In this paper they predicted less ice than 2007 (a new record low) provided that weather forcings (not part of their model) remained substantially similar to 2007. Apparently they did not because the prediction was wrong. Unfortunately I have yet to find a followup paper explaining why the prediction was wrong. The paper emphasizes the use of thickness in the model as a major part of the prediction of extent. But if the thickness is wrong, then the predicted extent would also be wrong. Likewise, if the thickness is wrong in hindcasts when thickness was not measured extensively, then hindcasts of volume would also be invalid. I believe that caveat belongs on fig 2 above.

118845. michael sweet at 10:47 AM on 23 May 2010
        Unprecedented Warming in Lake Tanganyika and its impact on humanity
        Johnd, Perhaps if you read some of the references that Chris gives you you will be less confused. In post 50, he refers to the Nyanza Project. This paper was written as part of that project. One of the lead scientists is a FISHERIES expert. I expect that Dr. Teirney discussed overfishing with them at some time during the month she was in Africa, and considered that information when she wrote this paper. Several other scientists are lake productivity specialists. These people spend their lives doing this work. Your insinuation that they are stupid and uninformed, because you have not bothered to read the background information is unconvincing. This paper is part of a large series of papers which document the lake. Your claim that they neglected some important facts because they wrote a different paper you have not read reflects only on you.
118846. Rogerthesurf at 10:38 AM on 23 May 2010
        Climate's changed before
        Response, Your reply is faithfully included in my blog. I am not disputing any of the findings that you mention in your answer, although some might, but none of this information proves in any way that anthropogenic CO2 is the root cause. My argument which is simply based on the standard scientific proof of a hypothesis, is not hard to understand, but for your benefit I will explain more. Even in the absence of previous warmings, the earth could be heating up for some other reason. The 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. The situation can be likened to the problem that pharmaceutical researchers have. If a patient is ill and you give him some of your new drug, and the patient gets well:- Did he get well because of the drug, or did he get well anyway? Very hard to tell, so as you should be aware, this problem is solved by doing double blind tests on a large sample of patients and doing a statistical analysis of the results. (Double blind because if the patient knows if he is receiving the drug or placebo, it effects his response, as the response is also effected if the person administering knows whether it is the drug or a placebo) To further illustrate the difficulty of proving a hypothesis, I recommend watching the following video. http://www.youtube.com/watch?v=TxiBHNeTG7o&feature=related The video has nothing to do with CO2 or global warming, but illustrates well the problems of hypothesis proof. A number of people died when the captain of this aircraft formed a hypothesis of what was wrong with the plane, an incident seemed to support his hypothesis, but in spite of definitive disproof of his hypothesis being readily available, because the hypothesis was incorrect, the aircraft crashed. In fact there are a number of known things which could cause the current warming, and probably a greater number of factors which are unknown. I hope this clarifies things for you and your readers. Please take the time to watch the video. This response is also posted on http://www.globalwarmingsupporter.wordpress.com Cheers Roger
        Response: "The fact that there are well documented and general agreement that there have been previous warmings... make CO2 as the root cause of global warming even less likely"
        
        The degree and global extent of warming is still debated for certain periods (re the Medieval Warm Period) but putting that aside, we can all agree that there have been many periods in Earth's history when the planet has experienced dramatic changes in temperature.
        
        Why has climate changed in the past? The primary driver of Earth's climate is and has always been changes in the planet's energy imbalance. If anything causes a change in the energy coming in or going out, that will lead to warming or cooling. This can include the sun getting hotter, more aerosols in the air reflecting incoming sunlight, more CO2 absorbing infrared radiation, etc. CO2 is not the only driver of climate - in the past, various factors have driven Earth's climate. The one constant is that an energy imbalance has driven temperature change.
        
        So what does past climate change tell us? It tells us that when the planet suffers an energy imbalance, global temperature changes. It doesn't mean CO2 is always the main driver of past climate change. The ice age cycles of the past million years were driven initially by orbital cycles, not CO2 (but CO2 does play a positive feedback role).
        
        A crucial piece of information we learn from past history is how much climate responds to an energy imbalance. How sensitive is our climate? And what we find is when our planet accumulates heat, there is a net positive feedback response from our climate which amplifies the initial warming. Past climate change reveals a key truth: our climate is sensitive. If you impose an energy imbalance on our planet, positive feedbacks will amplify the initial warming.
        
        What does this have to do with CO2? We know rising CO2 is causing an energy imbalance because of direct observations (satellites observing less infrared radiation escaping to space and surface measurements of more downward infrared radiation).
        
        So we have two pieces of information from empirical data:
        
        1. Direct measurements today find CO2 is imposing an energy imbalance
        2. Past climate change finds the climate is sensitive to an energy imbalance
        
        Our understanding of climate comes from considering the full body of evidence. You need to consider past climate change in the context of the current energy imbalance imposed by CO2.
118847. Doug Bostrom at 10:19 AM on 23 May 2010
        Unprecedented Warming in Lake Tanganyika and its impact on humanity
        Here's a nice example of cognitive disconnect: My comment about checking the local temperature was having a shot at those who had gone off on a tangent drawing all manner of conclusions about AGW when the study was primarily about sardine production. Title of article under discussion as it appears in Nature: Late-twentieth-century warming in Lake Tanganyika unprecedented since AD 500 I'm sorry johnd but I find you unreasonable in the technical sense of the term.
118848. Doug Bostrom at 10:09 AM on 23 May 2010
        There is no consensus
        Against the Chicago rally of policy think tanks, industrial interests and latter-day Don Quixote researchers bereft of a Panza to look after their linens, let's stack the National Academies of Science and their unit the National Research Council. NAS has just released a rather stunning compendium of climate research findings, mitigation options and adaptation possibilities. Here's the takeaway for us laypersons, from the climate research portion of the set: 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. You can find the press summary of the reports here. A free-to-read version of the report is here Now I'm sure that we'll hear squawks from people entirely clueless about what the National Academies represents to the effect that the NAS is simply ensuring that grant money continue flowing but consider, if their conclusion is that anthropogenic climate change is a settled fact beyond dispute, that hardly serves as an incentive to pouring more money into research, does it? In any case such an argument is worthless in terms of offering an alternative to accepted research findings.
118849. johnd at 10:07 AM on 23 May 2010
        Unprecedented Warming in Lake Tanganyika and its impact on humanity
        doug_bostrom at 08:24 AM, and e at 08:45 AM, the key point being missed is that the variations of layers of BSi deposited on the lake bottom was interpreted as variations of the lake productivity, in the scope of the study, further translated into sardine production. Using one core sample, which doesn't seem to allow for the reports on how variable the sardine productivity is over the 700km long lake, nor how the lake surface temperature varies, the study was able to find some correlation of the inferred variations in productivity with ALREADY reconstructed GLOBAL temperatures over the same time frame. The supposed proof of the relationship is that sardines catches have fallen in recent decades whilst lake surface temperatures had risen as recorded by instruments over the last 90 years. The problem I see is that for the connection to be validated the rate of BSi deposition over the last 90 years has to correlated with the lake surface temperatures that have been recorded, and that is where this study is weak. Firstly, the relevant top of one core was unable to be used, and the bottom of the other one was not used for some unspecified reason, so there is only assumed continuity. Secondly other studies, one which I provided the link for in an earlier post, collected samples in a more controlled manner taking surface samples along a designated transect in two different locations and found variations of BSi in the order of 0.01-1.07% and 0.1-2.9% at an assumed sedimentation rate of 1mm/year. The Teirney study determined a sedimentation rate of 0.5mm/year which was used to model age for the top 100mm, and their analyse yielded a BSi content varying from 10-60%. The BSi difference may be due to different lab procedures, but as can be seen the Tierny % varies by a factor of 6 whereas in the other study by factors of up to 100 or even closer to 300 across the two, hence their noting of the high variability and the need to recognise this if paleoclimate studies are to be conducted in the lake.. Thirdly, overfishing appears as not to have been considered a possibility, whereas elsewhere in the world declining fish numbers are blamed on that. My comment about checking the local temperature was having a shot at those who had gone off on a tangent drawing all manner of conclusions about AGW when the study was primarily about sardine production.
118850. Albatross at 09:26 AM on 23 May 2010
        Unprecedented Warming in Lake Tanganyika and its impact on humanity
        e @115, Don't forget Menne et al. (2010).

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