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All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

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Comments 118901 to 118950:

  1. Doug Bostrom at 11:52 AM on 22 May 2010
    Unprecedented Warming in Lake Tanganyika and its impact on humanity
    Johnd, I don't think I'm being hyperbolic or unnecessarily pejorative to categorize that remark as rubbish. Can you please state exactly where the study concludes "the primary productivity of the lake, both currently and for the past 1500 years, is solely a function of global temperatures?" If you can't do so, do you have the grace to retract your remark?
  2. Unprecedented Warming in Lake Tanganyika and its impact on humanity
    Without my having to say so David Horton has summed things up very nicely. Quote: "It would be nice to see, just once, a denier come to terms with the fact that we now have masses of evidence of very different kinds and from all over the world all of which support and strengthen each other." On their own the individual studies don't really represent that much, however when one starts to stitch them together and the mosaic begins to appear, the overall picture of the health of the planet starts to become clearer. But then I don't expect all to have an eye for Picasso, most prefer Rembrandt.
  3. David Horton at 10:26 AM on 22 May 2010
    Unprecedented Warming in Lake Tanganyika and its impact on humanity
    Looks like in johnd we have another classic denier argument - that is that no sample, no sample size, is ever big enough or comprehensive enough to demonstrate global warming, in fact, it seems, no sample can ever BE big enough. Here is another independent study which matches what every other study shows, and it comes from a new and very different location. And it's not just one core sample, but two. Worth remembering that sediments by their very nature are averaging out conditions over wide areas and over time. And the response? Not enough samples. I am not a betting man, except on sure things, and I bet that if there had been three cores, 4 would have been demanded, 4 needs 5, and so on to an infinity of samples from every square metre of the lake floor. And we would then be told that this was just one lake, that we couldn't possibly conclude anything until a second lake had been cored. Oh, you have 2, 3 are needed, and so on. And then, what, only lakes in eastern Africa? Only lakes in Africa, southern hemisphere, the world? It would be nice to see, just once, a denier come to terms with the fact that we now have masses of evidence of very different kinds and from all over the world all of which support and strengthen each other. As Charles Darwin said, in a slightly different context, it would only take one example to prove the theory wrong. The converse is not true, cherry-picking in the sense that every individual study has to somehow completely stand alone with 0 error bars might be a recipe for delaying action on climate change, but it has nothing to do with science.
  4. Unprecedented Warming in Lake Tanganyika and its impact on humanity
    Ron Crouch at 09:08 AM, my understanding of the study is not whether the lake is warming or not, but rather that the primary productivity of the lake, both currently and for the past 1500 years, is solely a function of global temperatures, to the exclusion of all other local and regional factors, and thus can be taken as a proxy for anthropogenic climate change.
  5. There's no empirical evidence
    Doug, perhaps it's time to let Tamino spend his spare time more productively than these trivialities. ;)
  6. There's no empirical evidence
    Doug-Bostrom, For my part, I would be grateful for you to invite (Dr?) Tamino or anyone else if they can contribute to the science questions raised here. I genuinely do not understand your second sentence. I was using the term "appears to be some sort of junk science site" only to describe the blogsite to which Riccardo referred me, not this site. I used this description because the article on that site appears to contain, well, junk science. And I have no idea what the "shiny dog whistle" metaphor refers to. Please clarify if it is helpful. Otherwise, I would prefer to stick to the science arguments.
  7. Unprecedented Warming in Lake Tanganyika and its impact on humanity
    Perhaps the latest study of global ocean temperatures which includes over 3200 Argo floats will help to convince you that the warming in Lake Tanganyika is consistent with enhanced global climate change. New Study Finds Ocean Warmed Significantly Since 1993 Quote: "The upper layer of Earth's ocean has warmed since 1993, indicating a strong climate change signal, according to a new international study co-authored by oceanographer Josh Willis of NASA's Jet Propulsion Laboratory, Pasadena, Calif. The energy stored is enough to power nearly 500 100-watt light bulbs for each of the roughly 6.7 billion people on the planet."
  8. There's no empirical evidence
    Riccardo, If you show me a mathematical expression that says A=B and then argue that a respected climate scientist says that A= 2B, then I am not likely to be convinced by the argument just because he is a respected climate scientist. My questions and assertions are strictly science-based. I may well be wrong, but someone needs to demonstrate that I am wrong in terms of physics and mathematics - whoever he is. I am asserting (#68) that "the guy who runs that site", respected scientist or not, is making a statement which is demonstrably false in terms of basic physics. It is founded on his misunderstanding of what the F term means in Schwartz 2007. I spent some time in post #65 explaining what the F term does mean to give the Schwartz model (or energy balance model if you prefer) some meaning. It is the stacking of instantaneous impulse forcings. As such F(t) in this model does not equal Q(t) - E(t). The respected scientist assumes that it does, which is what leads him to a statement that is demonstrably false.
  9. Unprecedented Warming in Lake Tanganyika and its impact on humanity
    chris at 00:55 AM, the reason I focused on this particular aspect is because I do have some practical knowledge of what is required and involved with relation to the subject of taking of samples. Granted it is in a different field with different objectives, geophysical, mineral exploration, bulk commodities, natural fibres, where the objective is not to get a confirmation of what we assume we know, but to quantify what we don't know. We might assume that the ground might be able to support a heavy structure, and a test at one corner might confirm that, but often that will not apply to the other corners. 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. In bulk commodities where a degree of consistency is easily assumed, there is an even stricter sampling regime that acknowledges the wide variation that can occur in all natural products. With natural fibres, wool in particular, it is accepted that the variation of micron within a single fleece is greater than the variation across the entire flock. Those who prepare the fleeces are well aware of this and often will go to one particular part of the fleece to extract a handful of wool that will make up a bale of special wool that ends up being awarded accolades as the worlds highest priced wool. However those who understand the game being played know that overall the flock that produced such wool is little different from the more run of the mill flock belonging to the next door neighbour. That might be comforting to those who wonder why the wool that gets pulled over their eyes often is so soft and subtle they are hardly aware of it's presence. ;-) In all fields it is relatively easy to take a sample that will confirm what anyone may want it to confirm is so desired, but in the field of commerce that desire is well recognised hence the strict regime and rules that apply, and it is from this perspective that I look to see if what is being presented as being representative of something bigger, does qualify in fact. Nothing more, nothing less.
  10. Doug Bostrom at 07:52 AM on 22 May 2010
    There's no empirical evidence
    Perhaps it's time to invite Tamino here to work things out w/PaulK? PaulK, you may well end up wasting your time here if you swerve an iota further into such remarks as "junk science", shiny dog whistle though the term may be.
  11. There's no empirical evidence
    PaulK, the guy that runs that site is a scientist that regularly publish on climate. If you wish to give up learning some rather simple science or if you think you have a better knowledge than climate scientists, feel free to waste your time elsewhere.
  12. There's no empirical evidence
    Riccardo, Sometimes, if you find yourself in a hole, it pays to stop digging. Your comment is wholly irrelevant to the question of what the F term means in the Schwartz model. Unfortunately, I am starting to suspect that you know that already. The site you referred me to for a "step-by-step explanation" appears to be some sort of junk science site, but in any event it is clear that the author of that site is not well trained in basic science. He is making the same conceptual mistake as you are in misunderstanding what the F term means in the Schwartz model, but he manages to “propagate” the error even further without making any attempt to question his own sometimes silly assertions. I quote from the site: Quote Now suppose that prior to our starting time, climate forcing was constant and equal to zero, and temperature departure was constant and equal to zero. After time t0, climate forcing increased to 1 W/m^2 and stayed there. Then the solution turns out to be: Theta(t) = (1 – exp(-lamda*t/C))/lamda Endquote It is hopefully evident to you that Theta (t), the temperature change from the forcing, must asymptote mathematically from this expression to a constant 1/lamda at large values of t. So now ask yourself the question whether it is possible in terms of first law of thermodynamics to have an imbalance of TOA radiative energy for an infinite time which results in a finite (constant) change in planetary temperature. If you can truly answer yes to this question , then I think that I am going to sign off, since I am wasting my time here.
  13. It's ozone
    The second link (to science.nasa) for the quoted JGR paper works no more, its abstract is here. A fully accessible link to the Scientific Assessment of Ozone Depletion: 2006 might replace it - or directly its Questions and Answers (2 MB). Re#3: For rising temperatures see e.g. here.
    Response: I've updated the broken link, thanks for the heads up.
  14. CO2 emissions do not correlate with CO2 concentration
    The rate of increase of CO2 levels had changed of course even in 1979 to 1982. It fluctuates a lot all the time, as visible from Mauna Loa or global data. This is due to due to the changing fluxes between atmosphere and other pools. A minor signal of yearly variability of human-emitted CO2 is scarcely detectable. A historic discussion of variability of concentration rise is within the Charles D. Keeling autobiography Rewards and penalties of monitoring the Earth from 1998. Excellent images on CO2, fossil fuels and the influences onto CO2 rise anomalies are within his 2005 Tyler Prize Presentation. A minor correction: Law Dome data have 2455 in its URL (the link within the text pointed to Tayler Dome, 2419).
    Response: Thanks for the heads-up, have fixed the link.
  15. Climate's changed before
    Rogerthesurf writes: In fact previous warmings disprove the hypothesis. That is a logical fallacy. Does the fact that previous fires were started by lightning disprove the hypothesis that a current fire was started by arson? I agree with the others above who say that you need to be more clear about exactly what it is that you're questioning. Be specific -- and if it's something that's discussed in its own dedicated thread on the site, discuss it there. Do you think CO2 is not a greenhouse gas? Or it is a greenhouse gas, but we're not increasing its concentration in the atmosphere? Or it is a greenhouse gas and we're increasing its concentration in the atmosphere, but negative feedbacks will keep the temperature uniform anyway? Unless you clarify what your question is, it's hard for others to answer it efficiently.
  16. Marcel Bökstedt at 04:00 AM on 22 May 2010
    Unprecedented Warming in Lake Tanganyika and its impact on humanity
    Albatross> I must admit that I was relying mainly on John Cook's remarks on the glaciers of Kilimanjaro on this site. They still make sense to me. If you want to question this, why don't you go to that "skeptic argument" and repost there? Then we could try to figure out what is true in the proper thread.
  17. Climate's changed before
    Roger writes "All that is in the explanation is a lot of theory which is not based on anything empirical" The explanation in this post describes how satellites have directly measured the change in the earth's outgoing and incoming radiation. This data does not come from models or theories, it comes from physical satellites with physical sensors which detect actual photons emitted from the actual atmosphere. None of this data collection process requires AGW to be true, photons are photons either way. This empirical data shows that CO2 in our atmosphere is absorbing and re-radiating energy just as predicted by AGW and associated theories. It is one of the strongest lines of empirical evidence underlying the theory. On top of this compelling evidence, past climate change is itself empirical evidence supporting the AGW theory. AGW and the theories underlying it predict a specific relationship between the earth's temperature and the various forcings that are theorized to affect it. This relationship can be confirmed or disconfirmed by examing reconstructions of the earth's climate and its various forcings. There are multiple independent methods for arriving at these reconstructions, none of them rely on AGW to be true. In general, the reconstructions depend on basic physical relationships between ambient temperature and various physical processes on earth. The reconstructions are created by observing actual physical evidence taken from the actual physical world, they do not come straight from models or broad theories. These independent methods all converge to the same picture of our climate's past, and are uniquely consistent with the predictions of AGW and associated theories. The same applies to observations of temperatures and forcings made within the past century, which, thanks to modern technology, can now be observed directly.
  18. Doug Bostrom at 03:11 AM on 22 May 2010
    Unprecedented Warming in Lake Tanganyika and its impact on humanity
    Second Riccardo's remark regarding the rift. Do more work before launching speculations. Again, use BP (our BP, not the oily BP) as a model for emulation. Though BP is frequently wrong he comes up with original ideas, puts a lot of effort into his ruminations, has good math chops (better than mine, that's for sure) and is also (and this is a key point) capable of recognizing and acknowledging those times when he's obviously incorrect. It's not guaranteed of course, but generally if you see a blindingly apparent feature such as the African Rift unmentioned in a paper you may safely conclude that it's not relevant. It helps to remember, though in the space we occupy here there's an artificial atmosphere of controversy, in the actual mainstream research community anthropogenic warming is not even slightly controversial, so it is not considered necessary to explicitly address every possible niggling objection that may be raised by folks unprepared to understand or accept research findings.
  19. Unprecedented Warming in Lake Tanganyika and its impact on humanity
    RSVP, as for the rift, i'd not call skepticism when not reading the information available. Indeed, you should read Tierney's page she linked before and, if not convincing, eventually comment on the explanation provided there.
  20. Unprecedented Warming in Lake Tanganyika and its impact on humanity
    Maybe I missed it somewhere, but I did not see any mention of this lake's level lowering and a possible correlation to temperature. It doesnt take much internet search effort to find that the level has changed historically and recently as well due to water being deviated by man. Down at the bottom of the lake there just happens to be a continental rift as well. The lake's temperature therefore doesnt seem like the best example for convincing Skeptics (like me).
  21. Unprecedented Warming in Lake Tanganyika and its impact on humanity
    ooops...can I point out that in my post 57 above [under (iv)], when I say "sea surface temperature" I mean "lake surface temperature"!
  22. Doug Bostrom at 01:14 AM on 22 May 2010
    Unprecedented Warming in Lake Tanganyika and its impact on humanity
    Chris thanks for that. The same approach and conclusions apply to a plethora of cases similar to this; folks leap to judgment based on their supposition they're reading research findings that are somehow atomic and self-supporting, when of course they're not. Another question for Dr. Tierney if she's about, not related to temperature per se. Inspired by johnd I was attempting to do what Chris just did and noticed you're looking at biomarker carbon isotope compositions and presumably ratios in your samples. By any chance, have you looked for the same recent shift in isotope ratios we see in the atmosphere and which are used to identify fossil fuel contributions to the carbon cycle? I expect we would see that if we were looking for it but am curious to know if you've followed that side path. It seems like that might be a way of identifying the first environmental fingerprints of our vast combustion project. I'm giving strong odds that this is something totally obvious to anybody working in the field and I'm simply oblivious, heh! Anyway, the methods you're developing and employing seem to have broad applicability and it'll be interesting to see what we discover as they're more broadly deployed.
  23. Unprecedented Warming in Lake Tanganyika and its impact on humanity
    johnd at 22:50 PM on 21 May, 2010
    "Of course armchair wannabees who have had little contact with the realities of the physical world, and even less appreciation of the infinite variability of all things natural, but instead see the world through lenses carved from ready made blocks of homogenised data interpreted by others may disagree"
    That's an interesting statement that bears on philosophical ideas about the nature of knowledge (or personal knowledge). I would say that my knowledge of the world is to a significant extent "based on ready made blocks of homogenised data interpreted by others". What's missing from that attempt at a perjorative are the truisms that (i) those "blocks" shouldn't contradict my personal experience and (ii) that the "blocks" can be accommodated within my mental picture of a subject formed from everything that I happen to know, also bearing in mind that the natural world has inherent degrees of order and that things "make sense". So I'm inclined to take what I read in the scientific literature at face value and afford it the presumption of "correctness" unless I have reason not to. I find this is a pretty useful approach in my own research. The notion that skepticsm involves the presumption of incorrectness is pretty self-defeating I think. The arrogance of assuming that one knows better than the practitioners of the research at hand, and that all the negative things you can think of that might be a problem, actually are a problem, doesn't help understanding. It tends to stop you investigating further. Far better if you think something might be a problem to do a bit of research, or enquire to the authors of the work. It's very likely that the negative things you've thought of have already be considered by the authors....so you might actually learn something!
  24. Unprecedented Warming in Lake Tanganyika and its impact on humanity
    johnd at 22:50 PM on 21 May, 2010 johnd, I doubt anyone would disagree that one core is not going to define every possible core that could be drilled in Lake Tanganyika. However the core and interpretations thereof are likely to have been considered in relation to a rather large body of work including: (i) prior studes to determine suitability for coring in lake Tanganyika, optimising coring sites and associated limnological analyses. (ii) A considerable amount of prior study to determine the suitability of the particular temperature proxy for paleotemperature analysis from lakes like Tanganyika (e.g. this detailed analysis [***]) (iii) Knowledge from analysis of surface temperatures in lake Tanganyika that seasonally-averaged temperatures from multiple sites in the lake (near Bujumbura, Kigoma, Lubugwe, Kibwesa, Kipili, Kipanka, Bujumbra), show very similar temperatures, indicating that sampling surface temperatures at single sites is representative of sites throughout the lake, particularly when averaged over significant time periods (http://www.ilec.or.jp/database/afr/afr-06.html) (iv) That direct sea surface and time-averaged air temperatures in many lakes, including Lake Tanganyika are strongly correlated, indicating that sea surface temperature measures and those from proxy analysis are likely to be well-correlated with air temperature at the times the surface temperature proxies were sampled. (v) That very extensive analysis of surface temperature measures shows that these are strongly correlated (rise and fall similarly) over long distances as yearly or decadal averages (NASA Giss establish that these correlations hold for distances of up to 1200 km). (vi) That the analysis of the direct measures of lake surface temperature, air temperature and primary productivity during the last century, indicate that the correlations assessed by analyses of the proxies are robust... ...and so on... In other words just like all scientific research, this study was done in the context of considerable prior research, and within a framework of strong knowledge of relevant climatology. Now this isn't my research area at all...no doubt the practitioners of this study have an almost infinitely (!) greater knowledge of this subject than I have, and thus considerably more insight into establishing the proper context of their work. [***] L. Powers et al (2010) Applicability and calibration of the TEX86 paleothermometer in lakes Organic Geochem. 41, 404-413
  25. Jeff Freymueller at 00:42 AM on 22 May 2010
    Unprecedented Warming in Lake Tanganyika and its impact on humanity
    Just as a data point here, we had a seminar speaker a month or two ago about the drilling project at Lake El'gygytgyn in the Russian Far East (also a paleoclimate project, but aiming to go back several million years to pre-glacial times). That was a much larger scale of project, with a drill rig and many tons of gear mobilized to a very remote part of Russia, set up on the lake ice, and drilling much deeper. We're talking about millions of dollars. That project got two cores. A third was planned, but drilling problems meant they just got two. All of this was done after extensive work of studying the lake water, multiple seismic lines, etc, to choose the ideal sites. I don't do this kind of work, but I am absolutely sure that the people who do are keenly aware of what conditions must be met for a sedimentary record like this to be considered a viable proxy for temperature, including the people who reviewed the paper. The fact that this project followed the same approach as other similar studies, followed extensive preparatory work, and was published after peer review from people who work in the field carries far more weight than the objections of someone who doesn't appear to have any conception of the scope of work needed to collect the core or go from core to paper, and doesn't appear to have even looked very hard for more information....
  26. Doug Bostrom at 00:23 AM on 22 May 2010
    Unprecedented Warming in Lake Tanganyika and its impact on humanity
    Just to yank us back to reality here, let's remember that the signal extracted from the cores obtained by Dr. Tierney is substantially consistent with -other- examples obtained elsewhere via different proxies. To the layman such as myself that alone is an indication that we're actually viewing a signal as opposed to some artifact or product of sample incoherence. It rather beggars belief that such a familiar shape should emerge by coincidence from a faulty sample. If Jessica is still hovering in the vicinity, perhaps the most valuable input she could contribute at this point would be a quick (if such is possible) synopsis of how one determines if a core is in fact reasonably intact, has not been mangled by previous bioturbation etc.?
  27. Unprecedented Warming in Lake Tanganyika and its impact on humanity
    'Skeptic' A: 'Climate science is all a huge hoax to get billions in grant money'. 'Skeptic' B: 'Climate science is too poorly funded to get 100% incontrovertible results and thus should be ignored'. Well, at least they've got all the bases covered.
  28. Unprecedented Warming in Lake Tanganyika and its impact on humanity
    johnd, a discussion based on unsupported hypothesis (too long shorelines, human or natural influences, etc.) and, above all, on the premise that scientists are more or less blind to all these things, is really pointless. If you have any real reason to think that the data in the paper are invalid or too limited, please enlighten us. Otherwise it's safer to assume that those who have been working in the field for years know better. First study the problem, then ask questions; and only then one may have a well founded idea.
  29. Unprecedented Warming in Lake Tanganyika and its impact on humanity
    chris at 21:37 PM, I inferred nothing of the sort. What does seem to be inferred by those who disagree with my concerns about whether the sampling provides representative data, is that one or two 2" core samples are sufficient to draw a conclusion about whats been deposited under a body of water covering 32,900 km². With a shoreline close to 2000 km and a wide variety of conditions and activities that affect the localised inflows and thus the sediments that collect on the lakes bottom, what are the scientific odds of being able to take one sample that yields results that represent the entire lake. Any prior work would have had to been very extensive in order to select such a target. Of course armchair wannabees who have had little contact with the realities of the physical world, and even less appreciation of the infinite variability of all things natural, but instead see the world through lenses carved from ready made blocks of homogenised data interpreted by others may disagree. But hey, thats life. Your impression about the low tech element is probably right. Core sampling of sediments is generally a low tech operation, even in a high tech world.
  30. Eric (skeptic) at 21:39 PM on 21 May 2010
    Has Arctic sea ice returned to normal?
    Found a link where PIOMAS was used for predictions within a season (2008) http://psc.apl.washington.edu/IDAO/seasonal_outlook.html The result shown in fig 2, http://psc.apl.washington.edu/IDAO/ensemble_fig2.gif is that the model slightly underestimated the Sept extent near the beginning of the season and overestimated towards the end (the final 8/1 prediction was higher than the actual Sept extent). I haven't found any followup on their 1 year predictions for 2008, probably because they realize there are too many weather variables that are outside the scope of the model. Looks like the best use of the model is to run it in the spring to predict the fall minimum. The 2010 prediction is here http://psc.apl.washington.edu/zhang/IDAO/seasonal_outlook.html and is for 5.3m sq km, slightly less than 2009.
  31. Unprecedented Warming in Lake Tanganyika and its impact on humanity
    johnd at 20:07 PM on 21 May, 2010
    "It leaves me wondering how many other such research projects have failed to see the light of day because the data collected was so bare bones that it was unable to be used."
    That's a perverse conclusion to draw from a study that was completed successfully. In my experience scientists go to extraordinary lengths to ensure that research objectives are achieved. Of course armchair wannabees can always winkle out negatives from otherwise positive experiences. I've been curious enough about this research to do a little background hunting. This seems a nice example of the broad weave of approaches to scientific analysis. Dr. Tierney might want to correct me, but my understanding is that this research was done in the context of a programme The Nyanza Project which has a major element or research training in the study of lakes (limnology). So much of the work was done involving students and research trainees under the supervision of mentors. The project covers a whole range of analyses as evidenced by the extensive publications arising from the project. A flavour of the coring project can be had from a "Backstory" in the same issue of Nature Geoscience. This shows that the coring study was built on studies of proviou cores that indicated that laminated sediments were obtainable from the lake, seismic imaging to determine the best locations for coring and limnological data to establish regional circulation patterns, nutrient mixing and so on, allof which helped to interpret the core data. So unlike your inference (johnd) this wasn't a "let's just stick a drill into a lake and pull up a core and see what might happen" event. It was built on careful prior studies just like all productiveresearch. On the other hand the project ws done in the context of a training programme, so I get the impression that there was a "low tech" element to this (Dr. Tierney might advise on that!). In any case it produced some very nice and informative data.
  32. michael sweet at 21:14 PM on 21 May 2010
    Unprecedented Warming in Lake Tanganyika and its impact on humanity
    Johnd, Perhaps you missed Dr. Teirney's CV (linked above) where it states she spent one month in Africa coring. I have done scientific collecting and it is very slow work. Bringing cores all the way back from Africa is difficult. Suggesting she leave valuable tools in Africa for possible return (!!) I will not answer. The lab work in these papers takes months or years to perform. This paper is a summary of all those long hours in the lab. Dr. Tierney's CV shows she has gone to other locations to do similar work. I look forward to that data when it becomes available. From many pieces you assemble a puzzle.
  33. Unprecedented Warming in Lake Tanganyika and its impact on humanity
    johnd, "It leaves me wondering how many other such research projects have failed to see the light of day because the data collected was so bare bones that it was unable to be used." It's everyday life of any scientist that experiment may, and actually often do, go wrong. It's really an easy guess that they're well aware. In any case, this problem is far outside the discussions on the scientific results we always try to have here, i.e. on experiments that did not go wrong. On passing, i'd like to thank Dr. Tierney and co-authors for having done the experiments, in first place, and for the time she spent here to explain the work done. Really invaluable.
  34. Unprecedented Warming in Lake Tanganyika and its impact on humanity
    scaddenp at 14:51 PM and Jeff Freymueller at 15:09 PM, read carefully, I did not suggest doing the lab tests on site, merely considering the possibility that perhaps the coring equipment remained on site until results were known. What I saw was a big risk expending so much time, effort and money to return with only two small core samples. There was no fall back position if the cores were unable to be tested properly or more importantly they yielded conflicting or confusing results. The more cores, the lesser chance of such possibility, and if money is really tight then being penny wise can often end up being pound foolish. Simple really. It is different for someone digging in their own backyard, but if it requires travelling to a remote location on the other side of the world, and funding is so tight that there is only one chance, then it simply has to be done right. It leaves me wondering how many other such research projects have failed to see the light of day because the data collected was so bare bones that it was unable to be used. It would be those that fail that make funding even harder to get, not those that achieve the objectives.
  35. There's no empirical evidence
    PaulK, actually what you call the "Schwartz model" is just the standard energy balance equation, widely used even in the scientific litterature. I think that you are confusing the equation written for absolute temperature with the one for temperature anomaly. You'll find a step by step explanation in the page i linked before. Indeed, it should be clear from the solution given by Schwartz that he's not solving dT/dt ∝ F(t); after linearization the equation is instead
    dΔT/dt ∝ F(t)−λΔT. My evaluation of the OLR comes from the assumption that the forcing is only due to an increased IR absorption which directly influences the OLR. A linear increasing forcing then comes from an exponential growth of CO2 concentration, given the aproximate but quite reasonable relation F=5.35*ln(C/Co) W/m2 where Co typically is the pre-industrial CO2 level.
  36. Lars Träger at 19:16 PM on 21 May 2010
    Why are there fewer weather stations and what's the effect?
    re #8: I did - and I certainly noticed that some of the least densely populated areas of Europe (like parts of Spain and France, West Scotland and Southern Scandinavia and the islands in the North Sea and Baltic Sea) are red, while some densely populated areas (like the Mediterranean coast and that lone spot in the middle of England) are not red. Blaming it all on the UHI effect is clearly wrong. re #28 On the fraud issue: that kind of fraud (Missing trader fraud) has nothing to do with what is traded (as it has been done with just about anything that can be traded) - the fact that this story was picked up by the Skeptosphere falls fully in line with why it does what it does the way it does.
  37. Has the greenhouse effect been falsified?
    Berényi Péter, the one I evidenced before, to begin with. Beyond that, what we know is that the measurements in fig. 1 behave like basic absorption/emission in the atmosphere dictates, the spectra nicely follow what's expected they should do, they also match what can be calculated from MODTRANS code. You, instead, throw in the discussion strange theories on the thermalization based on a descriptive graph found on Wikipedia to conclude that either those cannot be real measurements or that some "undocumented trick" (fake data?) has been used. Astonishingly.
  38. HumanityRules at 17:27 PM on 21 May 2010
    Unprecedented Warming in Lake Tanganyika and its impact on humanity
    It is great to see Jessica posting here. If you have more time to post I'd be interested in your thought on local/regional changes around the lake that may contribute to change. Your paper seems to put all change down to processes controlling global climate change which would leave little room for local changes having any affect. I've been trying to find an estimate on population change around the lake, with little success so assume it's impressive, and others have raised land use changes as a possible contributer to reduced productivity. I'd be interested in your thoughts? I guess another way of looking at this is any attempt to monitor and control local processes completely pointless giving the overarching control by global processes suggested by your paper? (Completely OT. I just came across this new paper on ocean heat content which has been a recent topic here. Authors include Josh Willis. Enjoy! http://www.nature.com/nature/journal/v465/n7296/pdf/nature09043.pdf)
  39. Doug Bostrom at 16:29 PM on 21 May 2010
    Unprecedented Warming in Lake Tanganyika and its impact on humanity
    Some folks would be well served to be more self-conscious about the rather paltry level of effort they're expending on this topic, versus that exerted by others. It's quite extraordinary how conspicuous is the difference. The reason why self-inflicted embarrassments of this kind matter is because most observers will find somebody sitting in their armchair lazily casting factually unsupported judgment on hard work, scrupulous attention to detail and articulate presentation of new facts performed by others quite unpersuasive. Enlightened self-interest suggests that more work is required in order to save face let alone sway opinion. Imitate Berényi if you want to follow an example of someone approaching genuine skepticism, which requires a substantial investment of time and energy in order to have any hope of being genuinely productive. The bar gets higher all the time, so expect to pedal harder and faster in order to keep up.
  40. Doug Bostrom at 16:10 PM on 21 May 2010
    Climate's changed before
    Roger, you appear to be missing a lot of important information which I suspect is why you're not connecting the dots here with regard to the order of precedence of discovery leading to present conclusions about climate behavior. Theories and observations originally unrelated in both primary intellectual domain and chronological order led to our ability to understand gross climate behavior and subsequently to the notion of anthropogenic climate change. It's not a matter of imagining that we might change the climate and then hypothesizing mechanisms that might cause such to happen. You've got it quite backwards. I sincerely suggest you temporarily set aside your internally generated hypothesis of how AGW appeared on our collective radar and start from the beginning. Dr. Spencer Weart's Discovery of Global Warming. Weart's book begins from first principles in a number of different scientific domains and spells out pretty comprehensively how what we know of physics and earth sciences leads ineluctably to the conclusion that we can in fact change the climate all by ourselves. Really, you owe it to yourself to read Weart. If you're looking for -actual- gaps in our understanding of climate and how humans may change climate, his book is your best place to start.
  41. Jeff Freymueller at 15:09 PM on 21 May 2010
    Unprecedented Warming in Lake Tanganyika and its impact on humanity
    #40 & #43. I missed the suggestion by johnd that you do the lab work on site. You might as well suggest doing the lab work on the moon. Even on a fully-equipped scientific drilling ship (like the Integrated Ocean Drilling Program ships), there are limits to what you can do on the shipboard labs. The limits of what lab work you can do in an African hotel room are far more severe. Jessica Tierney may check back in, but my guess is that you might not even dare split the core in the field for risk of losing everything. Get the samples, protect them like crazy, get them back to where you can do real work on them.
  42. Unprecedented Warming in Lake Tanganyika and its impact on humanity
    Do the testing while still on site???? This lab work looks expensive and very unlikely that you could schedule it while still on site. You could write to the author and ask but I would suspect that there was some delay between getting core back to lab and getting all that analysis done. If my institute were doing it, you would wait months or longer. Consider the ice coring. With only one core, there is indeed all kind of questions you couldnt answer for sure till more coring had been done. However, demanding a comprehensive sampling program from the GISP or Summit programmes would have asking a lot. I dont see this is much different.
  43. Jeff Freymueller at 14:34 PM on 21 May 2010
    Unprecedented Warming in Lake Tanganyika and its impact on humanity
    In almost every funded research project I have had, I have stretched funding to the limit to always collect more data in the field than originally proposed. And yet, sometimes I dearly wished I had collected a little bit more. But you have to keep the money to pay the graduate student, even when you might risk being able to pay your own salary. Funding is always tight, because in (probably) every field there are more good research proposals than there is money to fund them. So the funding agencies almost always dole out as little as they can to every project, to spread what they have around, and you get pretty close to the minimum possible to do your project. I have had projects where the mobilization cost was a depressingly large fraction of the total field cost, and there was nothing I could do about it -- what I had was what I had. All of that is a long way of saying that criticism of Tierney et al. for only having gotten two overlapping cores seems pretty ridiculous to me. I'm sure they got as much data as they possibly could with the funds that they had. And I think it would be more useful to get cores from some of the other rift valley lakes rather than trying to pepper Lake Tanganyika with more cores -- if the other lakes did not tell the same story then you would go back and do more systematic sampling.
  44. Unprecedented Warming in Lake Tanganyika and its impact on humanity
    johnd at 13:51pm on 21 May, 2010: Yes, you're right, the mobilisation costs might well have been a very large component of the total cost of obtaining the cores. However, given the scarcity of funds for many scientific investigations, it might be that there simply wasn't enough money to get more cores, when you consider extraction, storage, transport, and analysis costs. I'm inclined to agree with michael sweet at #37 - while it would have been nice to get a comprehensive set of data for this one lake, it might be better to spend additional funds to do similar investigations of other lakes through the southern hemisphere, to improve the coverage of climate data.
  45. Unprecedented Warming in Lake Tanganyika and its impact on humanity
    scaddenp at 13:11 PM, the reality is that the biggest expense would have been mobilising the equipment and personnel. The operating cost to obtain each additional core a lesser cost, lab time a relatively minor expense. The danger always is that after going to all the trouble to undertake the project, stopping after only taking 2 small cores is that if the cores are not usable or yield conflicting results, then all the time and expense has been totally wasted. On the other hand if the cores are tested whilst the equipment is still on site, is it right to stop just because part of each the first 2 cores gave the right answer. There is no basis on which to establish the level of confidence that a proper sampling regime would be designed to produce.
  46. Unprecedented Warming in Lake Tanganyika and its impact on humanity
    Wow! And all the laboratory time is free? Considering how much is inferred from just one oil well I find this a bit precious. Undoubtedly more data would be better - it always is - but real world intrudes on our desires so we do what we can. Just regard this as one more brick among a great many others. Please suggest to your local politician that science needs more funding. I for one never have enough data and given price of oil wells, I am not likely to get it either.
  47. Unprecedented Warming in Lake Tanganyika and its impact on humanity
    michael sweet at 11:36 AM, I appreciate that more data means more time, effort and expense, however your estimate of years to obtain extra data seems unrealistic, I think days should be closer to the mark. Because I am aware of the difficulties in undertaking similar such work, I cannot help but wonder why after taking the trouble to mobilise equipment and personnel to such a location, why only take one or two cores each about 1.5 metres long when all the hard work has already been done? It would be interesting to see how long was spent getting mobilised and how long actually spent sampling. However, at the end of the day, irrespective of the reasons, the reliability, or the confidence that can be expressed in the results obtained is primarily a function of the sampling regime more so than the accuracy of any laboratory analysis or data processing.
  48. Climate's changed before
    Roger - where are you getting this idea from? Besides the papers that John's article points to you (especially Harries and Evans) you might consider your "previous warmings disprove this hypothesis". They do? How? Do you consider that fact that, say, more energy from sun earlier caused a warming as proof that GHG isnt warming us now when there is no extra energy from the sun? If you look at the IPCC WG1, chapter on paleoclimate you will see reference and outputs from numerous models that consider past forcings and compare with past temperature. The physical model that climate change is function of solar, albedo, GHG and aerosol works very well to explain past climate (eg see Benestad & Schmidt 2009) and that model also leads us to conclude that humans, especially through our emissions, are changing climate. Consider the scientific process involved too. A model is derived out of basic physics - at heart it is a heat balance based on conservation of energy. From the model come a lot of predictions about what we should be observing. The match of observations to prediction gives us confidence. We can also apply it to the past to see that previous climate change is accounted for within model (within the very considerable error bounds imposed by the uncertainties in past forcings and observations of climate). Because it is a physical model, not a statistical model, you can compare predictions for say a solar forcing to a GHG forcing (eg and especially stratospheric cooling). All in I would say that gives very considerable support to current climate theory.
  49. There's no empirical evidence
    Riccardo, Thanks for the Forster and Taylor reference. I am still digesting, but it looks as though the GISS models along with all of the other models overestimate LW positive feedback and hence underestimate OLR in the observational period. The information here is not definitive, but sometimes if something looks like a duck and quacks like a duck... Thanks again.
  50. michael sweet at 11:36 AM on 21 May 2010
    Unprecedented Warming in Lake Tanganyika and its impact on humanity
    Johnd, I think you are asking for unrealistic amounts of data. As you point out the data from Lake Tanganyika are limited and do not provide 100% certainty. On the other hand, it takes an enormous amount of time and funds to obtain this data. If Dr. Tierney went back she would have to work for years to obtain a small improvement on the data. I think her time is better spent collecting data somewhere else. The Lake Tanganyika data is validated and supported by the data collected elsewhere. When we see a pattern of data from a variety of sources it validates all the data. Ten lakes that all have similar data sets are more informative than one lake extensively surveyed. No one would suggest making economic decisions about AGW based solely on this data. This data adds to the rest of the data on AGW to give compelling reasons to take action.

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