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johnd at 11:19 AM on 23 May 2010Unprecedented 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. -
Doug Bostrom at 11:12 AM on 23 May 2010Climate'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. -
johnd at 11:04 AM on 23 May 2010Unprecedented 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?" -
Eric (skeptic) at 11:00 AM on 23 May 2010Arctic 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.
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michael sweet at 10:47 AM on 23 May 2010Unprecedented 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. -
Rogerthesurf at 10:38 AM on 23 May 2010Climate'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 RogerResponse: "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. -
Doug Bostrom at 10:19 AM on 23 May 2010Unprecedented 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. -
Doug Bostrom at 10:09 AM on 23 May 2010There 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. -
johnd at 10:07 AM on 23 May 2010Unprecedented 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. -
Albatross at 09:26 AM on 23 May 2010Unprecedented Warming in Lake Tanganyika and its impact on humanity
e @115, Don't forget Menne et al. (2010). -
Unprecedented Warming in Lake Tanganyika and its impact on humanity
Si >"doug you need good data. One tree does not a hockey stick make ;-)" You are misunderstanding Willis's argument. It's not that the reconstruction is "bad" per se, but that it hasn't been calibrated to surface temperatures. This suggests that the record may be off from absolute correct temperatures by a certain factor. That factor would remain constant however, so the overall shape of the trend (which is what we are interested in) would not be affected. This is the point that doug is making. >"You are going to have to wait for Anthony's surface station report but it is coming!" Thanks, we know. He's been promising it for a long time now. Ask yourself this: why does Watts spend so much time documenting "bad" weather stations, but never bothers to plot the temperature records of "bad" stations vs. "good" stations? It's a rather trivial thing to do. In any case, we don't have to wait for his report, others have done the work for him. You can read about the results here, and John's posts here and here. As it is off topic from this post, please post any followups to the weather station discussion to one of those two posts. -
Albatross at 08:55 AM on 23 May 2010Unprecedented Warming in Lake Tanganyika and its impact on humanity
From Tierney et al's web page: "What about Geothermal heating? Isn’t Tanganyika in a rift zone? Could that be responsible for the warming? Lake Tanganyika is indeed part of the East African rift system. 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). That’s 10-fold less than the estimated heat absorption of the lake since 1913 thought due to global warming (0.4 watts per meters squared; Verburg and Hecky, 2009, Limnology & Oceanography). What is more, were there increased volcanism we would detect a change in the water chemistry of the lake (which has not been observed), plus we would see a thermal “inversion” - warmer waters in the depths of the lake. In fact, as you can see below from an inset graph from our Nature Geoscience paper, the deep portion of the lake (hypolimnion) is cooler than the surface and middle-portion of the lake (110 meters depth) and the deep waters are warming more slowly than the surface waters. This is consistent with a heating source from above - not below - the lake." -
Albatross at 08:53 AM on 23 May 2010Unprecedented Warming in Lake Tanganyika and its impact on humanity
Si, SS and johnd, How many Vostok ice cores were made? And I am not talking about individual core samples. How about EPICA? At how many locations did they drill cores for those projects? Regarding the red herring of hydrothermal actvity. Authors addressed that see #79. Also, have you thought for a minute that those vents have probably been present for millenia, and that they are on the lake bottom and the authors are talkiing about warming of LST. That is akin to Monckton claiming that El Ninos are caused by undersea volcanoes, or thinking that that undersea volcanoes explain the increase in 0-2000 m glbal OHC. If the lake was being warmed from below, the lower depths would have locally been warming at a rate much higher than has been observed and the LSTs would not be consistent with the surrounding SATs, which they are. These data have clearly not been contaminated by hydrothermal activity. Really guys, you are grasping at straws and it is all too painfully apparant. SS says s/he has spent a few days looking at this on the internet. Wow, really? Scientists have devoted careers and students 5-6 years of their PhDs studying this issue and thereby reading hundreds, if not thousands, of papers. Not to mention that this paper was reviewed and critiqued by their peers, who are experts in the field. The contrarians do not like the findings because they are yet more evidence that AGW is an issue and add to an already coherent and cohesive picture. So the best they can do is to try and make some rather lame attempts undermine the scientists' credibility. Johnd @100, "LOL. Has anyone happened to notice that this study is basically about fishing for sardines?" Please gorow up and show some respect. If you have not noticed the obvious, we have not had thermometers around for anywhere close to 1500 years, nevermind isolated equatorial regions in Africa. Tierney is probably reading some of the contrarian comments on this read and shaking her head in disbelief, and who can blame her. And for those willing to accept Eschenbach's "critique" of the Tierney et al. paper at face value, I would caution you against doing so. Willis has a reputation for, how shall I say this, for playing loose with the facts as has been shown several times by Dr. Lambert and others. That and the fact that he is not an expert in this field. EOS. -
Si at 08:52 AM on 23 May 2010Unprecedented Warming in Lake Tanganyika and its impact on humanity
doug you need good data. One tree does not a hockey stick make ;-) Saying over and over that it is just 'the big picture see the trees dont mind the quality feel the width' is entirely missing the point. You are going to have to wait for Anthony's surface station report but it is coming! -
Si at 08:48 AM on 23 May 2010There is no consensus
And here is his comment after the conference: "I’ve just returned from the Heartland Institute’s Fourth Annual Climate Conference, at the Marriott Hotel in Chicago, where something very interesting was emerging: a clear counter-consensus on climate change. Of 700+ delegates, 400 or so were scientists in relevant disciplines – arguably more than on the IPCC’s much vaunted panel (after you allow for non-scientists, scientists in irrelevant disciplines, and dissenting reviewers). These scientists came from around the world, and from highly respected academic institutions. They were by no means unanimous, but all (except for two token Warmists) agreed that the IPCC “consensus” is deeply flawed, and that the policy prescriptions based on the IPCC’s work are extremely unlikely to deliver significant results." Looking forward to reading Robert Carters new book 'Climate -the Counter Consensus' -
Unprecedented Warming in Lake Tanganyika and its impact on humanity
johnd > The method they used to arrive at their conclusion was to measure an indicator (BSi)of the lakes productivity (at one sole location) and correlate that with already reconstructed global temperatures. You are missing a key detail, they also used the TEX86 temperature proxy to reconstruct lake temperatures for the past 1500 years. This is a separate method from the measurement of BSi; it is a temperature proxy, not a proxy of productivity like BSi. This yields three independent measurements: lake temperature record, global temperature record, and lake productivity. they found that all three of these measures correlate with one another, hence their conclusions. > If the objective was merely to make the connection between the lakes surface temperature and global temperatures, would not it have been better just to check the temperature records from relevant locations around the lake? The temperature record doesn't go back 1500 years. -
Si at 08:42 AM on 23 May 2010There is no consensus
This is relevant to this topic. It is from Roger Helmer talking before the 4th International Conference on Climate Change which he recently attended. Of the 80 speakers, I noticed that fully forty-five were qualified scientists from relevant disciplines, and from respected universities around the world -- from the USA, Canada, Mexico, Russia, Sweden, Norway, UK, Australia and New Zealand. All of them have reservations about climate alarmism, ranging from concerns that we are making vastly expensive public policy decisions based on science that is, to say the least, open to question, through to outright rejection of the Anthropogenic Global Warming (AGW) model. Several of these scientists are members or former members of the IPCC Intergovernmental Panel on Climate Change. But how do 45 sceptical scientists stack up, you may well ask, against the 2500 on the official IPCC panels? But of course there aren't 2500 relevant scientists on the IPCC panel. Many of them are not strictly scientists at all. Some are merely civil servants or environmental zealots. Some are economists -- important to the debate but not experts on the science. Others are scientists in unrelated disciplines. The Chairman of the IPCC Dr. Ravendra Pachuari, is a Railway Engineer. And of the remaining minority who are indeed scientists in relevant subjects, some (like my good friend Prof Fred Singer) have explicitly rejected the IPCC's AGW theory. Whittle it down, and you end up with fifty or so true believers, most of whom are part of the “Hockey Team” behind the infamous Hockey Stick graph, perhaps the most discredited artefact in the history of science. This is a small and incestuous group of scientists (including those at the CRU at the University of East Anglia). They work closely together, jealously protecting their source data, and they peer-review each other's work. This is the “consensus” on which climate hysteria is based. And there are scarcely more of them than are sceptical scientists at this Heartland Conference in Chicago, where I am blogging today. Never mind the dozens of other scientists here in Chicago, or the thousands who have signed petitions and written to governments opposing climate hysteria. Science is not decided by numbers, but if it were, there is the case to be made that the consensus is now on the sceptical side. -
Doug Bostrom at 08:24 AM on 23 May 2010Unprecedented Warming in Lake Tanganyika and its impact on humanity
...would not it have been better just to check the temperature records from relevant locations around the lake? You mean from the instrument shacks installed in the year 1000? No, that's not possible. You'd need a proxy for that. Maybe a core from the lake bottom? To summarize once again my objection to your objection, "I doubt it" is not a useful contribution. Si, you leave unaddressed the issue that Willis is obsessed with accuracy when accuracy is not the point. Same mistake as with the failed thermometer inspection project run by WUWT, debunked for the same basic reason Willis' critique of Tierney is pointless. -
Unprecedented Warming in Lake Tanganyika and its impact on humanity
Si >"And AGW getting stronger? More like DOA." Considering the theory was built up slowly and methodically over the better part of a century, I fail to see how it is "DOA". To exand on dhogaza's comment on what constitutes a significant percentage of climate scientists, please see John's post on scientific consensus. -
johnd at 08:10 AM on 23 May 2010Unprecedented Warming in Lake Tanganyika and its impact on humanity
doug_bostrom at 07:07 AM, actually a lot did go wrong with the samples, both at the top and the bottom. That is why only a portion of each was used, the equivalent of more than one core apparently discarded. As well, extrapolation was needed to date the bottom portion of the used portion as there was some reversal of age indicated at depth. -
dhogaza at 08:07 AM on 23 May 2010Unprecedented Warming in Lake Tanganyika and its impact on humanity
Si... "doug. I dont think Willis makes the mistake you mention. He is having a critical look at Jessica's paper - thats what scientists do." Scientists do it competently. Willis is no scientist, and his personal track record is one of incompetency, so I for one won't bother to read his piece at WUWT (or elsewhere). " I think there are rather more skeptical climate scientists than you realise. - Spencer, Michaels, Christy" I could've sworn there were at least a dozen (/snark). Si clearly doesn't understand that three (or a dozen) vs. thousands isn't exactly a large percentage ... -
johnd at 07:58 AM on 23 May 2010Unprecedented Warming in Lake Tanganyika and its impact on humanity
doug_bostrom at 07:07 AM, which particular congruency are you referring to? -
Si at 07:48 AM on 23 May 2010Unprecedented Warming in Lake Tanganyika and its impact on humanity
doug at 92 - I think you answer your own question! If Willis & the commenters at WUWT are right and the the data is poor then any conclusion is invalid. e and Phila, 94 and 95. I think there are rather more skeptical climate scientists than you realise. - Spencer, Michaels, Christy And AGW getting stronger? More like DOA. Maybe you meant climate science - yes it will get stronger. I think the AGW argument is basically is lost. But that does not mean that all climate science is duff. It does mean it should be completely separated from energy policy. The reason climate science gets such attention is that is has a large bill attached. And yes it may be irksome to have to reiterate basic science - but that's education for you (some people are still arguing about evolution). So let's keep discussing and reading - it's a fascinating subject! -
johnd at 07:43 AM on 23 May 2010Unprecedented Warming in Lake Tanganyika and its impact on humanity
doug_bostrom at 05:11 AM, there seems to be a lot of misunderstanding or confusion about what the findings of the report were. This is taken from the abstract, "We conclude that these unprecedented temperatures and a corresponding decrease in productivity can be attributed to anthropogenic global warming" http://www.nature.com/ngeo/journal/vaop/ncurrent/abs/ngeo865.html LOL. Has anyone happened to notice that this study is basically about fishing for sardines? The method they used to arrive at their conclusion was to measure an indicator (BSi)of the lakes productivity (at one sole location) and correlate that with already reconstructed global temperatures. If the objective was merely to make the connection between the lakes surface temperature and global temperatures, would not it have been better just to check the temperature records from relevant locations around the lake? It would have saved a lot of the contortions that it appears to be causing. -
Doug Bostrom at 07:07 AM on 23 May 2010Unprecedented Warming in Lake Tanganyika and its impact on humanity
Thanks johnd, that was indeed an interesting read. I'm unmoved by your speculations; Tierney's methodological explanation is vastly superior in actual detail compared to "maybe something went wrong with the samples." Besides which we still have the congruency to explain. -
johnd at 06:35 AM on 23 May 2010Unprecedented Warming in Lake Tanganyika and its impact on humanity
doug_bostrom at 11:52 AM, perhaps if we go back to the basics and look how the proxy was developed. A direct link was created between the deposits of biogenic silica (BSi) found in the core sample and lake temperatures. The lack of correlation for the charcoal obtained from the core was used to rule out rainfall as an influence on the rate of deposition. Other indicators as to whether the replenishment of nutrients from any of the many inflows or any part of the shoreline were excluded from consideration by the limited core samples taken that could have identified possible sources remote from the lake itself or activity close by. Logic dictates that if any material is being deposited in the sediments it must be replenished from somewhere unless it is in a constant decline, and if the rate of replenishment varies that would be reflected in the rate of deposition. If you haven't read this study referenced below you may find it interesting if read carefully, particularly the advice on site selection within the lake if undertaking paleoclimate reconstructions, the accepted methods they used to take multiple samples along transects, but in particular, I repeat, in particular, the extremely wide variation of the BSi content within the numerous samples collected. http://www.geo.arizona.edu/nyanza/pdf/Powers.pdf -
Doug Bostrom at 06:30 AM on 23 May 2010Unprecedented Warming in Lake Tanganyika and its impact on humanity
[let's be civil, please!] Sorry! That's what comes of not hitting "preview." Always good to be reassured someone's actually reading all our blather. :-) -
Phila at 06:13 AM on 23 May 2010Unprecedented Warming in Lake Tanganyika and its impact on humanity
[let's be civil, please!] Sorry! That's what comes of not hitting "preview." Thanks for the gentle reminder. -
Phila at 05:55 AM on 23 May 2010Unprecedented Warming in Lake Tanganyika and its impact on humanity
#91 "I think not. The more critical we are the better the science will be. That papers get picked over and pulled apart...." Yes and no. If someone like Lindzen is critical, that's one thing. But if someone who doesn't understand the basic concepts of AGW is critical, and routinely mistakes lazy contrarian speculation for a new and improved form of "peer review," that's not really useful, IMO. I think it'd great to have a "more robust science," and I'm sure everyone here agrees with me. But if skeptics want to contribute to that result, they need to become conversant with the basic science and the rules that govern it, at the very least. You can't simply leapfrog over these requirements and present yourself as a climatologist's peer or inquisitor. What I object to is not the desire for democratization, but the assumption that there is or should be no entrance fee, in the form of doing one's [let's be civil, please!] homework. I'm sure you'd like astrophysics and virology to be more robust sciences too, but I suspect you don't spend much time instructing scientists in those fields on First Principles. -
Unprecedented Warming in Lake Tanganyika and its impact on humanity
Si >"The more critical we are the better the science will be." Yes, but true scientific criticism generally comes from other practicing scientists, especially those in related fields of study. This ensures that those employing the criticism are well versed in topics relevant to the field. If scientists tried to address all the criticisms of amateur skeptics, they would be spending all their time rehashing basic principles and never moving the science forward. For sure, there are legitimate scientists on the skeptic side (Lindzen being one), but their number is tiny compared to those accepting the mainstream position. It seems that an inordinate amount of criticism of AGW comes from amateurs who feel that their every issue and misunderstanding must be addressed before the science should be considered robust. I can't think of any scientific discipline that holds itself to such an impossible standard. In the end though, I think you are right that it makes the science more robust. In that regard, it is telling that the scientific consensus supporting AGW has only grown stronger in the face of this overwhelming scrutiny. -
Doug Bostrom at 05:11 AM on 23 May 2010Unprecedented Warming in Lake Tanganyika and its impact on humanity
Thanks for the clarification (pun?) on Langenberg, Si. A lot of observations but apparently none to rebut Tierney's central finding, that of a temperature record closely resembling that produced by numerous other measurement methods from a diversity of other geographically dispersed situations. Now, one could say Tierney's wrong somehow, but that leaves hanging the question of why the record she's derived bears such an uncanny resemblance to so many others, which of course also mutually coincide. Any hypothesis to explain this resemblance should include a mechanism yielding such a set of coincident signals. We have that mechanism at hand, predicted by fundamental physics and apparently confirmed by a host of observations. At WUWT I read misplaced concern about data points as opposed to statistical lessons from data collections, innuendo about Mann, sophomoric remarks about "Hockey Teams" and the like but I see absolutely nothing that will coherently explain how Tierney's results are so closely congruent with what we expect to see and in fact have seen in numerous other data sets. So, no useful contribution, just a lot of "I doubt it" or elliptical departures from the objective of Tierney's work. No utility of the kind you refer to, Si, when you extol the virtues of the activities at WUWT and elsewhere. -
Doug Bostrom at 04:57 AM on 23 May 2010Unprecedented Warming in Lake Tanganyika and its impact on humanity
Si, you don't think Willis is swerving into misplaced concerns with absolute accuracy? Can you explain what he's writing about, if it's not absolute accuracy? Why are he and you, too, apparently so disturbed by by the relative paucity of calibration data? Regarding your later remark, the utility of criticism depends on its validity and ability to further progress. So far I've seen little evidence of that; Lindzen is about the best data point available but he appears to have become entirely fixated on a hypothesis that has proven unable to improve on others' work. -
Si at 04:41 AM on 23 May 2010Unprecedented Warming in Lake Tanganyika and its impact on humanity
Phila "The problem is that a small group of amateurs has decided to hold climate scientists to an impossibly high standard that most of them apply to no other field. Any science that tried to appease this degree of contrarianism would be doomed to stasis at best." I think not. The more critical we are the better the science will be. That papers get picked over and pulled apart (Teardown you call it in hardware) means that Climate Science will move out of the cosy club it has been and become a much more robust science. This site is helping in that by questioning your 'small group of amateurs' (I think Richard Lindzen et al might object to that description). -
Si at 04:27 AM on 23 May 2010Unprecedented Warming in Lake Tanganyika and its impact on humanity
doug. I dont think Willis makes the mistake you mention. He is having a critical look at Jessica's paper - thats what scientists do. I think he makes some interesting points and gets even better comments in the thread eg Hu McCulloch's- odo take a look. -
Si at 04:17 AM on 23 May 2010Unprecedented Warming in Lake Tanganyika and its impact on humanity
John the relevance of Langenberg to Tielney is that he is another young student studying the lake but comes to different conclusions - of course they are not attention headline grabbing ones but such is life. In brief (and not my summary but from Pat Moffat) • No evidence of increasing lake clarity as a result of secchi measurements since 1946 • The interplay of stratification and plankton productivity are not “straightforward” • Challenges O’Reilly’s assumption on the correlation of wind and productivity -the highest production is on the end of the lake with the lowest winds • A strong caution using diatoms as the productivity proxy (it is one of two different lake modes) • No ability to link climate change to productivity changes • More productivity from river than allowed for in Nature Geopscience article • Externally derived nutrients control productivity for a quarter of the year • Strong indications of overfishing • No evidence of a climate and fishery production link • The current productivity of the lake is within the expected range • Doesn’t challenge recent temp increase but cites temperature records do not show a temperature rise in the last century • Phytoplankton chlorophylla seems to have not materially changed from the 1970s to 1990s • Disputes O’Reilly’s and Verbug’s claims of increased warming and decreased productivity • Rejects Verburgs contention that changes in phytoplankton biomass (biovolume), in dissolved silica and in transparency support the idea of declining productivity. A large part of the lakes production may be picocyanobacteria -
Phila at 04:12 AM on 23 May 2010Unprecedented Warming in Lake Tanganyika and its impact on humanity
#86 "it might be good to dispell these "obvious" issues and not make assumptions about what the reader is inclined to believe." That sounds great in theory, but in practice it would be very hard to anticipate every single issue that a "skeptic" might seize on while looking for an excuse to downplay or disregard scientific findings. The problem isn't that Nature is making incorrect assumptions about its readership. The problem is that a small group of amateurs has decided to hold climate scientists to an impossibly high standard that most of them apply to no other field. Any science that tried to appease this degree of contrarianism would be doomed to stasis at best. -
Doug Bostrom at 03:37 AM on 23 May 2010Unprecedented Warming in Lake Tanganyika and its impact on humanity
RSVP, you think Nature is a journal aimed at the layman? It's not. Publishing in Nature guarantees an audience beyond any narrow domain of research but that audience is well versed in the practice and conventions of scientific publication. As you know. Temperature trends are a key metric of climate behavior. As you well know. -
RSVP at 03:29 AM on 23 May 2010Unprecedented Warming in Lake Tanganyika and its impact on humanity
Phila quotes doug_bostrom about my remark etc. "In reality, as Doug Bostrom says, if a problem of this type seems "obvious," there's a pretty good chance that it's not a problem at all." I see the article as directed to the less initiated (sort of an intro into this subject about the temperature of the largest lake in Africa). As such, it might be good to dispell these "obvious" issues and not make assumptions about what the reader is inclined to believe. Aside from this point, were'nt local temperature conditions suppose to be irrelevant in terms of proving or disproving global warming? -
Doug Bostrom at 03:28 AM on 23 May 2010Unprecedented Warming in Lake Tanganyika and its impact on humanity
Si, Willis appears to be committing a mistake that we (and especially folks at WUWT) should have left behind a long time ago. Willis is missing the forest while scrutinizing pine needles, conflating the significance of temperature trends w/ the importance of absolute accuracy of temperature measurements. The instant he latches onto problems with accurate calibrations is when he runs off the rails and misses the big picture. The fundamental objective here is to look for trends, not what exact temperature it was on a given day. Tierney necessarily needs to establish some sort of base temperature around which to hang the data she derived from her cores, but in point of fact that choice is not really important, it's the shape of the graph that is noteworthy. It's interesting to observe that comments on Willis at WUWT note the resemblance of Tierney's graph to others including of course Mann's famous example. They allude of course to incompetence, etc. because they have nothing else to say but fail to explain why so many sources of data should resemble one another in the shape they present when plotted. -
Doug Bostrom at 03:11 AM on 23 May 2010Unprecedented Warming in Lake Tanganyika and its impact on humanity
Si, it's worth thinking for a moment about what the implications would be if Tierney had -not- found a temperature signal resembling that found elsewhere. Really, take a moment to ponder that. Blame does not really enter into the equation. -
Si at 03:04 AM on 23 May 2010Unprecedented Warming in Lake Tanganyika and its impact on humanity
Another young student, Victor Langenberg’s 2008 thesis (Wageningen University) On the Limnology of Lake Tanganyika http://edepot.wur.nl/121977 should make for an even more interesting comparison.Moderator Response: Perhaps you're new here and don't know, if you provide a link to a paper or other resource at SkS you're expected to explain why you think it significant to the discussion. -
Si at 02:31 AM on 23 May 2010Unprecedented Warming in Lake Tanganyika and its impact on humanity
E at 79. I agree with the sentiment here -climate scientists are not incompetent or indeed involved in a conspiracy. But Jessica (at 30) admittted that again it is a case of blaming CO2 as the likely culprit. Hardly a convincing argument. -
Phila at 02:31 AM on 23 May 2010Unprecedented Warming in Lake Tanganyika and its impact on humanity
Skepticstudent, Please try to bear in mind that you're essentially accusing real people whom you've never met of incompetence or worse. Basic human decency would require you to offer very strong evidence, even if the scientific method didn't. You should also bear in mind that as you labor to discredit every single study you don't like by dreaming up alternative explanations, you're creating a highly counterintuitive picture: An accumulation of data from all over the world that combine, coincidentally, to present the "illusion" of AGW. At some point, you have to understand that this is a far more improbable scenario than the one you're so desperate to debunk. -
sylas at 02:23 AM on 23 May 2010Has the greenhouse effect been falsified?
I am very grateful for comments which have picked up a couple of errors in my original essay, now fixed. I will continue to accept corrections with thanks, and update the essay as appropriate to get rid of errors. I may not agree with all the criticisms or corrections suggested, however. I do not see any problem at present with the wording being used, which at the time of writing reads: When you look down from aircraft at 20km altitude (Fig 1a), what is "seen" is the thermal radiation from Earth that gets out to that height. Some of that radiation comes from the surface. This is the parts of the spectrum that follow a line corresponding in the diagram to about 268K. Some of that radiation comes from high in the atmosphere, where it is much colder. This is the parts of the spectrum that follow a line of something like 225K. The bites taken out of the spectrum are in those bands where greenhouse gases absorb radiation from the surface, and so the radiation that eventually escapes to space is actually emitted high in the atmosphere. The atmosphere's main IR window (the region of IR transparency) is around 800 to 1000 cm-1 in wavenumber, or about 10 to 12.5 microns in wavelength. Some of the radiation to space DOES come from the surface, and the wavelengths to look for surface radiation are those in this IR window. Wording can always be tweaked a bit, but I don't see any problem with what is there at present. The IR window in this specific case is almost all from the surface. The main point here is that we can observe the greenhouse effect at work. It is not falsified; it is a notion known from basic physics for well over a hundred years and it is now amply confirmed in measurements such as those I have shown and also such as those shown in the site linked by Berényi: IR Transmission Spectra. For example, take the midrange-IR spectrum shown for Mauna Kea, which matches most closely the range of Figure 1 in the blog. I show the image on the page, and below it a reversed image with wavenumbers written into the horizontal scale for a slightly easier comparison with the figure in the blog. I have also added a horizontal line at transmission level 1 (fully transparent).
This also shows what is wrong with the specific criticisms made against Figure 1 in the blog. Berényi says:
On the other hand, since IR transmittance in window is ~80%, [...snip...]
It means the radiance curve in Fig. 1 can not be produced by actual measurement or if it was, what is shown is a scaled up version of values measured. Undocumented tricks like this are not helpful.
Figure 1 is produced by actual, unscaled measurement. There are no undocumented tricks. Your problem here is assuming the ~80% IR transmittance. That is simply not valid. You can see clearly that it is not the case in Mauna Kea data either. And while you are right that Mauna Kea is high altitude... why not also note that the Artic is high latitude? It makes a comparable difference.
Mauna Kea is at an altitude of 4200m, which is enough to get about 90% of the water vapour in the atmosphere; quite so! But it is also in a humid climate, where you have a high tropopause and lots of water vapour at low altitude. So sure; at low altitude in Hawaii you would have less IR transmittance (though you cannot assume a globally based mean figure will be a good specific estimate for this or any other location). But the Arctic regions, where the Fig 1 data was collected, have much lower specific humidity than Hawaii.
Even if you don't trust the data I have supplied, you need a much better basis for presuming it is inaccurate and presuming to scold on that basis. Be skeptical by all means. I will try to get hold of the actual data myself if I can and follow up. But please be assured that I am not deliberately distorting things.
You remain the most helpful contributor here for cleaning up errors in the blog post. I'd like to continue a constructive engagement. You are welcome to be skeptical, but without being overly sensitive... I'd really appreciate a bit more credit myself for not trying to be deliberately deceptive. Can we do that?
Cheers -- sylas
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Si at 02:22 AM on 23 May 2010Unprecedented Warming in Lake Tanganyika and its impact on humanity
Skepticalstudent...looks like you agree with Willis then who concludes in his article "My point is, the Tierney 2010 report is a study of the change in Lake Tanganyika surface temperature over time, which contains no measurements of the change in LST over time, and which has exactly three actual surface temperature measurements, which are poorly cited, are from different parts of the lake, and are all from 2003 …" Jessica, is he right? -
Si at 00:52 AM on 23 May 2010Climate Change and the Integrity of Science: a letter to Science
Great thread! At 62. Monckhausen "We are running a small but fine blog taking on these deniers with something they do not have: humour" I thought those skeptics were pretty funny actually www.cartoonsbyjosh.com -
Unprecedented Warming in Lake Tanganyika and its impact on humanity
Skepticstudent writes "Did they know about the thermal vents at the bottom of the lake in numerous locations before they wrote this article and spent all that time?" Actually the authors were well aware of geothermal activity in the lake. The issue is addressed in their comments here. >"... I'm attempting as do the majority of skeptics to show that there are many natural causes that add to the whole." Why do you and a majority of skeptics constantly assume that climate scientists are so incompetent as to be unaware of this fact? You are shown to be wrong time and time again yet you continue to make these assumptions. -
mspelto at 20:51 PM on 22 May 2010Unprecedented Warming in Lake Tanganyika and its impact on humanity
In terms of the comments on Kilimanjaro glaciers, I referenced Rwenzori glaciers because they are closer and to the wetter environment, do not lose mass significantly via evaporation. Thus, it is only temp and ppt. that matter more typical. The glaciers are also at a lower elevation which yields climate more in line with their surroundings. -
Doug Bostrom at 17:40 PM on 22 May 2010Unprecedented Warming in Lake Tanganyika and its impact on humanity
Skepticstudent, you're not keeping up and you're making yourself look foolish. To wit: ....does one really have to worry about wattage output into the water to wonder if they could output heat into the lake? How much heat? You do realize, the heat energy released into the lake versus the mass of water contained in the lake determines whether the hydrothermal vents will have any significant impact on the temperature of the lake compared to other inputs? Right? So you need to quantify that or you're not making a argument with any effect. One would also have to admit that these thermal vents are pushing co2 as well as sulphur to the surface... Ok, that last statement is completely diagnostic of your traction problem. You need to start at the beginning. Read this: Weart's Discovery of Global Warming. See, getting your head around Weart's book or the complete equivalent is a prerequisite for conducting useful discussion of the entire topic of AGW including the little fragment we're treating here. You can't do long division before you know how to add and subtract. You can't be a "skeptic" without knowing enough about the topic to avoid making blunders such as imagining that C02 entering the lake from hydrothermal vents will somehow affect the temperature of the lake in the same way C02 in the atmosphere at large helps to control the temperature of the lake. Really, do yourself a favor and read Weart. It'll take you some hours but for anybody who is inclined to spend time noodling around on Google Scholar-- such as yourself-- it's actually quite entertaining. And it's free, the web edition that is. -
Riccardo at 17:18 PM on 22 May 2010Unprecedented Warming in Lake Tanganyika and its impact on humanity
skepticstudent, it could be helpful if you link directly to the paper instead of copy/paste author, title, affiliation and address. What Doug was trying to say, I guess, is that one has to be quantitative in their hypothesis. No one is saying that there is no volcanic activity in the lake. The point is the impact on the overall behaviour of the ecosystem. For sure Dr. Tierney and co-workers are well aware of the presence of vents in the lake and we can take it for granted that their hole was not digged near one of such vents, even if not stated explicitly. Remember, research papers have no didactic intent (by definition, i'd say). And while we are all welcome to have a read, it's absurd to criticize them for not being explicit enough on many things. Even worse if you question author's skill in doing accurate research. Do you really think you have something to teach them on how to choose the proper drilling site? Do you really think that one day they just dropped some instruments on a boat and start drilling at random? Not even a newbie fisherman would do this, his first question would be where to go.
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