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kdkd at 07:28 AM on 19 June 2010How climate skeptics mislead
This thread is very interesting. And with BP being one of the most prominent so called sceptics on this site, he's given us a lot of interesting information about his approach. The fundamental issues seem to be:- No understanding or acknowledgeement of the fundamental difference between scientific problems and engineering/mathematical/logical problems
- Related: misapplication of logic, with some confusion between what is an inductive approach and a deductive approach. As well as the inappropriate of the logical inverse where convenient (e.g. #215)
- Failure to look at the big picture, rather inappropriately insisting that a reductionist approach is the only possible way to understand the problem space. It's pretty well established that in the non experimental sciences where complexity is a significant component, that reductionism will not result in a comprehensive explanation
- Weighting evidence based on how it is perceived to bring the evidence for AGW into doubt, rather than on its quality, or the provenance of the source
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How climate skeptics mislead
BP, No, I do not want you to prove it. Where did you see that? Disprove, that's what you need to do Sorry, you're right I mispoke. What you suggest is that we take your hypothesis as true until we can disprove it. I maintain that that is a silly approach. -
How climate skeptics mislead
BP, again you're ignoring my point that this post is about the big picture of AGW, a theory that is inherently predictive. Anyways, in order to form a constructive proof of your claim, you would need to go back in time and place thermometers at various distances from every site measured in the temperature record. What you are actually doing is taking limited data and then extrapolating a generalization: that there is a logarithmic UHI effect relative to population. You are then retrodictively applying that generalization to the entire temperature record. Sorry, but that's induction. And yes, I have read Spencer's post and understand the principle he proposes. Where exactly does he say that his analysis is conclusive? I will wait and see if some peer-reviewed research comes out of it, until then it is an interesting question, but it provides no reason to seriously doubt AGW as it stands. -
Is the long-term trend in CO2 caused by warming of the oceans?
Lon Challenge response: Pull back to 1850. According to most data, the temperature was pretty much flat at a value about 0.8C less than now. My model would show CO2 would stay constant. No! It would show the RATE of CO2 accumulation would be constant. You have to integrate to get back to the change in LEVEL. Why do you persist in making this elementary error? The question remains, is the rate your model predicts accurate? How about you actually try it out? Ned at least put a little effort into his argument. -
Berényi Péter at 06:08 AM on 19 June 2010How climate skeptics mislead
#212 e at 05:02 AM on 19 June, 2010 As it stands now, the only evidence of this hypothesis is the contents of a blog post by Roy Spencer Puh-leeze. Not that Spencer mantra again. Go back and read, would you? Spencer was the first to notice logarithmic dependence of UHI on population density extends well below rural levels, but. As I have already told you several times it can be demonstrated in a much simpler way. And lo and behold I have given here, in this fine blog all the details you may need to understand it. such a proof will never be available, it cannot exist when empirical science seeks to make predictions Listen. I know my English is substandard, but how can you read "predictions" where I ask for "you find the actual error and show it"? I do not want you to make any prediction just some debugging job. If an instance of something (i.e. error) is actually shown, it is called a constructive proof as opposed to an existence proof, where only the existence of such-and-such an entity is proven without giving a clue how to find it. Just in case you have not studied math. how we must keep going until we have "proven" your hypothesis No, I do not want you to prove it. Where did you see that? Disprove, that's what you need to do. Really, is your tendency to attack straw men intentional? -
Doug Bostrom at 05:57 AM on 19 June 2010How Jo Nova doesn't get the tropospheric hot spot
Gary, it might help your understanding to carefully consider what is implied by "questioning the data." Many of these questions resolve to doubt without substantial justification for that doubt. UHI is s great example of that phenomenon. Published scientific literature is the most useful refuge from confusion. The farther you go from the journals, the more pointless noise you're going to encounter. -
NickD at 05:53 AM on 19 June 2010How Jo Nova doesn't get the tropospheric hot spot
"I have yet to see data in support of a position on either side of the AGW debate go unquestioned." And you likely never will. Personally I look at what evidence stands up to the questioning and scrutiny rather than calling it a wash because it is all questionable in some way. To each his own, I suppose. -
cynicus at 05:51 AM on 19 June 2010How Jo Nova doesn't get the tropospheric hot spot
NewYorkJ: I think that's a good question because a 'real' skeptic might conclude from this discussion: no tropospheric hotspot thus no change in adiabatic lapse rate. So apparently the surface hasn't warmed -> see, the surface temperature measurements are all flawed and scientists are just suffering from confirmation bias, or worse; fraud! -
garythompson at 05:36 AM on 19 June 2010How Jo Nova doesn't get the tropospheric hot spot
Great post John and like always I enjoy learning from your site. For a long time now I've been struggling with the reason why so many intelligent, well meaning people can't seem to come to the same conclusion with regard to AGW. And based on the people who post on this site I lump roughly 90% of them into that category of general truth seekers and not those on the fringe who only have an interest in confrontation and 'winning' the argument. While reading this article, it has occurred to me that the complexities of Climate Science are so daunting and our understanding of it so in its infancy that we lack the rock-solid data to prove without a shadow of a doubt one side of the argument or the other. I thought the one solid measurement upon which we could agree was OLR but obviously from John's article and the Science of Doom article there is still plenty to debate with regard to measurements and interpretations of OLR reduction due to CO2. Surface temperatures are erroneous and biased by UHI, proxy data are questioned, satellite data is questioned (in this posting), etc. It seems that both sides are 'skeptical' when it comes to measured data that don't support their position. When will this end? When climate science has advanced far enough where the models are complete and account for things such as clouds, aerosols and other variables that are poorly understood? When, after decades, these AGW predictions don't materialize? I have yet to see data in support of a position on either side of the AGW debate go unquestioned. I welcome links to papers/articles that the community feel meet that lofty goal. -
How climate skeptics mislead
BP, >I have not talked much about other lines of evidence, much less the entire theory in this thread. Then why bring the issue up in a post about the "big picture" of the theory AGW? Surely you see there are some implications made in doing so? You're beginning to sound disingenuous. I take no issues with you trying to find evidence for this singular hypothesis, I take issue with its implied relevance to AGW theory as it stands today - not some hypothetical future where your claim has been "proven". As it stands now, the only evidence of this hypothesis is the contents of a blog post by Roy Spencer. Even he admits it's extremely preliminary. There is no way that our discussion here is going to change that, only peer-reviewed research can be the foundation for solid evidence of this claim. It is from this current state that I claim the hypothesis is implausible. Does that really seem so outrageous? Furthermore, KR makes the point that even in this hypothetical future where such evidence exists, your evidence would still need to be weighed against all other evidence if we are to make any conclusions about broad theory. This is exactly the point made by this post to begin with. >However, a constructive proof is always stronger and if available, is preferred to existential ones. I don't think this point is sinking in for you BP: such a proof will never be available, it cannot exist when empirical science seeks to make predictions. The proof you speak of - whether constructive or existential - is the sole domain of mathematics and formal logic. You can never "prove" that the UHI effect exists as you say it does, you can only show evidence that it exists. Even if you were able to produce some peer-reviewed evidence on the subject, that evidence itself would still be subject to uncertainty. You cannot assume your own evidence is gospel truth while other evidence is "shaky" or uncertain. If you were able to show some hard evidence for this particular UHI effect, we would be left with at least two contradictory theories that are both plausible: a) the earth is not warming to the degree scientists believe, and SST's and satellite measurements are in error (not to mention all the other evidence of a warming earth) b) the earth is warming, and your evidence for UHI is in error or some other error exists in the land surface measurements that imposes a cooling bias. Again, both of these theories would plausible with the given evidence. You cannot simply declare with certainty that one is true and another is false. If we want to come to any conclusion whatsoever, we are forced decide whether one theory is "better" or more likely than the other. This is not an arbitrary scenario, this situation (multiple mutually exclusive plausible hypotheses) is the case in any field of empirical science of non-trivial complexity. You can never truly eliminate the possibility that an alternative hypothesis - either known or unknown - is true. This is the core problem with induction that has been debated by philosphers for centuries. It's a philosophically interesting problem, but in the end, if you seek to remove the tools that allow us to compare and rate plausible hypotheses relative to one another, then you are seeking the elimination of nearly all scientific knowledge. I think we're starting to run in circles here. We keep explaining to you that there is no such thing as certainty in science (whether we are talking about conclusions or evidence for those conclusions). You seem to agree, but then go off on tangents talking about how we must keep going until we have "proven" your hypothesis or "completed the job" of removing uncertainty from our measurements. I'm starting to wonder whether you are arguing for the sake of argument. -
NewYorkJ at 05:01 AM on 19 June 2010Peer review vs commercials and spam
Svensmark: There was no substantive criticism of our work Translation: We didn't like the criticism of our work. Svensmark: We sent it to 4 different letters, but each time met with refusal. This shows that if you keep submitting sub-par material to one of the many dozens of relevant journals, you'll eventually find a lax, incompetent, or non-independent reviewer. In some unfortunate cases, the editor will just roll with the individuals you've "recommended" as reviewers, which removes the independence entirely. This happened with Lindzen and Choi. L&C, GRL, comments on peer review and peer-reviewed comments -
NewYorkJ at 03:56 AM on 19 June 2010How Jo Nova doesn't get the tropospheric hot spot
Chris Colose had a nice post on this awhile back. Skeptics/Denialists Part 2: Hotspots and Repetition He mentions that lack of a tropical tropospheric hotspot (assuming the questionable studies that claimed this were correct) would likely imply a greater climate sensitivity. Any comments on that aspect? -
carrot eater at 03:29 AM on 19 June 2010How Jo Nova doesn't get the tropospheric hot spot
Alexandre, AGW has nothing to do with it, in particular. If the surface warms, regardless of why, there should be somewhat amplified warming in the troposphere. If the surface cools, regardless of why, there should be somewhat amplified cooling in the troposphere. On a perhaps simplistic level: If the lapse rate did not change, then the troposphere and surface would warm or cool at the same rate as each other. But with some warming, the absolute humidity of the air can increase, and this will change the observed lapse rates, due to the moisture effects mentioned above. If the lapse rate is changing over time, then the trends at the surface will be different from the trends further up. Take that as a rough sketch, but I hope nothing is fundamentally wrong there. If there is, others will jump in. -
Alexandre at 03:17 AM on 19 June 2010How Jo Nova doesn't get the tropospheric hot spot
I second carrot eater´s question. A trend is mentioned, but I failed to understand what causes it. Is there any projection about the hot spot trend as a response to AGW? -
carrot eater at 02:23 AM on 19 June 2010How Jo Nova doesn't get the tropospheric hot spot
This treatment is missing some clarity I think. Tropospheric amplification (relative to the surface) means that the lapse rate is itself changing, due to changes in humidity. I see it written here that there is a lapse rate, and that dry and moist lapse rates are different from each other. What I don't see here is a discussion of why the observed lapse rates would change over time. -
Albatross at 02:16 AM on 19 June 2010Astronomical cycles
Chris @39. Heading out of town, so I don't have time to address HR's "points". But I see that you did, excellent job as always Chris, thanks. Ken Lambert, "Chris, this “nice AGW trend” is not looking so nice when the purported energy flux imbalances are not showing up in OHC for the last 6 years and probably not much in the last 16 years." Sigh. Really, why do people feel the need to keep resurrecting long debunked myths. Your "argument" has been addressed here, and specifically in Fig. 1 of Trenberth (2010). Climate scientists (e.g., Dr. Latif) have warned us not to expect a monotonic increase in global surface air-temperatures. Yet "skeptics" continue to jump on every perceived short-term slow down or cooling period in the data. Nothing is being hidden here-- the official record is quite noisy, and scientists now know that internal climate variability can be an important modulator of regional temperatures (e.g., NAO, AO, PDO) and some even of global temperatures (e.g., ENSO). Not to mention the short-term impacts of volcanism, and the known (and limited) impacts of the solar cycle. That noisy record is one of the reasons why one needs to consider 20-30 years of temperature data to derive a statistically significant trend. In addition to the very troubling problems with the paper and method identified by Riccardo: If there is some solar element to this, why does the Stratosphere continue to cool (yes O3 destruction explains some of that cooling but not all of it). Also, it would have been useful for Scafetta to quantify the forcing strength of his mechanism in WM-2. How does the strength of this alleged forcing compare to that of CO2? If real, it may have been comparable in the past, but will it be int he future as CO2 forcing continues to escalate? If his hypothesis is correct, we should see a marked downturn in global temperatures between until 2018 or so. Personally I have no intention of waiting/delaying another 8 years to (in all likelihood) see this hypothesis falsified, and I doubt very much that policy makers will either. Trying to take comfort in the belief that some hitherto undiscovered natural cycle is somehow responsible for the observed warming is not pragmatic, scientific or responsible. Especially when the overwhelming evidence and data points to an significant anthro component. -
dhogaza at 02:16 AM on 19 June 2010How Jo Nova doesn't get the tropospheric hot spot
It's worth pointing out that radiosondes were never meant for climate work, but like surface stations, were deployed to gather data for improved weather forecasting. "Close enough for horseshoes, hand grenades, and weather forecasting" ... This particular misunderstanding of the meaning of the "tropospheric hot spot" has been explained so endlessly that Jo Nova has to be intentionally misleading people. -
Steven Sullivan at 02:11 AM on 19 June 2010Peer review vs commercials and spam
Unless PLoS Medicine behaves much differently from the PLoS journals I know about, the Ionnadis article itself was peer-reviewed. And therefore...most likely false? And no, chriscanaris, peer review isn't 'as good a system *as any*'. And CoalGeologist, no one has ever claimed that peer review has a nonzero failure rate; there is no denial among scientists that peer review isn't perfect. If AGW skeptics require something impossible, then it's their problem, not science's. richard.hockey, the EMBO J model is still peer-review. It's just more *transparent* peer-review. Why should peer review's 'days be numbered'? To the chagrin of internet warriors, the fact is that in matters scientific, all opinions are not equally valid. -
monckhausen at 02:00 AM on 19 June 2010Astronomical cycles
As expected, Scafetta's paper is used as evidence for the sun being the driver of climate change: http://friendsofscience.org/assets/files/documents/2010_June_Newsletter.pdf Derek, FoGT -
monckhausen at 01:56 AM on 19 June 2010How Jo Nova doesn't get the tropospheric hot spot
Same principle applies to cooling (granite) plutons...there referred to as crystallisation heat. Derek, FoGT -
Berényi Péter at 00:35 AM on 19 June 2010How climate skeptics mislead
209 KR at 12:46 PM on 18 June, 2010 picking one line of evidence, bringing up some objection (of varying strength), and then stating that based on that singular objection to a particular data set that an entire theory supported by many lines of evidence is now suspect - that all supporting lines of evidence/data sets (such as the several satellite sets you refer to) are therefore invalid I have not talked much about other lines of evidence, much less the entire theory in this thread. It were you guys, who did it. I've just mentioned if UHI is proven to have a significant effect on past land surface temperatures, something has to be done to restore consistency. And this conditional statement is simply true, don't even try to argue with it. You have managed to force me into some guesswork on conceivable sources of error in satellite lower troposphere data (it was the atmospheric model used to convert brightness temperatures to air temperatures which is not independent of other datasets), but I would not stick to that on all cost, since I didn't have a sufficiently thorough look at the satellite issue (yet). At the same time I do maintain my stance on UHI adjustments of past surface temperatures as they're done in mainstream climate science being fundamentally flawed. I have shown you in detail why I think it is so and why proper adjustments should be almost an order of magnitude higher. The whole thing is pretty simple and easy to understand. If you really think there must be an error in it somewhere, because multiple independent lines of evidence contradict it, that's fine. It's like an existential proof in math. You can convince anyone who firmly believes in the external evidence you cite. However, a constructive proof is always stronger and if available, is preferred to existential ones. To see its validity, much less is to be assumed. Therefore as soon as you find the actual error and show it, even people not impressed by other lines of evidence would be either forced to get convinced or demonstrate for everyone to see they would never listen to reason. You all have chosen not to follow this constructive path, either because it was impassable or you are actually not interested in convincing anyone by reason who is not convinced already, but hope to succeed by other devices like appeal to authority, emotional extortion, referring to irreducible complexity or any number of such techniques. Unfortunately it is not an exceptional attitude, but an everyday experience of outsiders dropping into the midst of the AGW crowd. It does demonstrate something, I'm just not sure what. But it gives that sinking feeling of sorrow. Thank you for the demonstration, Berényi. You are welcome. -
Riccardo at 00:30 AM on 19 June 2010Astronomical cycles
Berényi Péter, Scafetta used an arbitrary trend without discussing it, so did I. -
thingadonta at 00:21 AM on 19 June 2010Uncertain motives: Theil misrepresents the science
The IPCC 2007 Himalayan glacier error was not a typo. I dont know here you get your information from, but since you deleted my previous comment suggesting lead authors knew the IPCC 2007 report's statement on himalayan glacier's was dubious, but decided to put it in anyway, for political reasons, here is the statement by the lead reviewer himself: "Dr Murari Lal also said he was well aware the statement, in the 2007 report by the Intergovernmental Panel on Climate Change (IPCC), did not rest on peer-reviewed scientific research. In an interview with The Mail on Sunday, Dr Lal, the co-ordinating lead author of the report’s chapter on Asia, said: ‘It related to several countries in this region and their water sources. We thought that if we can highlight it, it will impact policy-makers and politicians and encourage them to take some concrete action. ‘It had importance for the region, so we thought we should put it in.’" Read more: http://www.dailymail.co.uk/news/article-1245636/Glacier-scientists-says-knew-data-verified.html#ixzz0rDKrbbIi To any normal-thinking person, this is what is called exagerating for political reasons. -
Berényi Péter at 22:51 PM on 18 June 2010Astronomical cycles
#44 Riccardo at 21:38 PM on 18 June, 2010 one may always show that a model is wrong using its same logic Huh? -
Riccardo at 21:38 PM on 18 June 2010Astronomical cycles
Berényi Péter, one may always show that a model is wrong using its same logic. Anyways, as you might have anticipated, I looked at GISS radiative forcing and fitted them with similar polynomials. Radiative forcing is quite flat for a while and then increases sharply, a second order polynomial just can't do it. Then, naively looking at radiative forcings as you did reinforced my findings, if anything. I didn't talk about it because it is not necessary to show the weakness of the paper and I did not want to see the discussion hijacked by topics like radiative forcings, aerosols, clouds, uncertainties on all of them and the like. I just wanted to show that the astronomical theory does not stand even the slightest scrutiny. -
chris at 21:30 PM on 18 June 2010Astronomical cycles
Ken Lambert at 20:58 PM on 18 June, 2010 "Unless this 'imbalance' heat shows up in the oceans; warming is not happening.." That's an extraordinary bit of flawed deductive reasoning Ken. Since global warming clearly is happening (all years of the 2000's warmer than all but one of the 1990's; Jan-May 2010 temperature average the highest on record), even despite the fact that the solar cycle has only just come out of a very prolonged minimum and we're in a supposed cooling ocean fluctuation "cycle"....and sea levels are continuing to rise at a rate that cannot be accounted for by land ice and glacier melt...there's something very wrong with your logic. Usually when deductive reasoning leads to conclusions that oppose extant reality, it's pertinent to look at the premises that drive the logic. In your case these are clearly flawed. There is no question that OHC has risen "during the last 16 years". Has OHC stopped rising "for the last 6 years"? Probably not. The sea level data and land ice melt data are incompatible with that conclusion. As usual in science we should wait until these apparent discrepancies have been sorted out before attempting ground-breaking interpretations..... -
neilrieck at 21:30 PM on 18 June 2010Astronomical cycles
I wonder if these astronomical cycles aren't distracting us from those published by Milankovitch. For those of you who have never heard of this before, the gravitational effects of other planets "do" affect Earth's orbital shape which changes from circular to elliptical and back over a 400,000 year period. The current shape is almost circular (an even amount of cooking on the spit). A second effect involves the tilt of Earth's axis (determines how different winter is from summer) which is currently 23.4 degrees and decreasing. A third effect involves precession (a wobble) which determines where the Earth's poles points when Earth is nearest the Sun each year. All these effects can be plotted to produce a resultant wave which would enable glaciations every 100,000 years (on average). http://en.wikipedia.org/wiki/Milankovitch_cycles The world was very skeptical about Milankovitch's theory until evidence for 100,000 year glaciations was found in ice cores from both Greenland (Century Station) and Antarctica (Vostok Station) as well as sediment cores taken from the Indian Ocean (Vema 28-238). Since then, more evidence has come from stalactites and stalagmites as well as other proxies. BTW, the ice cores are good for 400-600k years while the sediment cores provide glaciation evidence going back 700-800k years. In most instances there was an interglacial period lasting 15-20k years. http://www.southwestclimatechange.org/climate/global/past-present Earth emerged from the previous glaciation about 12,000 years ago. In all previous interglacial periods the temperature rises naturally. Warming oceans begin to release dissolved CO2 into the atmosphere which then acts as a feedback to reinforce the warming cycle (and buffer future changes). The only difference between previous interglacial periods and the current one is that this time, billions of industrial humans have precharged the atmosphere with CO2. As the oceans warm, more oceanic CO2 will be added to industrial CO2 to make things much worse. CO2 emissions from volcanoes can only drive the levels higher. { in all these lines I have omitted, but not forgotten, other GH gasses like methane, water vapour, etc. } Does this mean that other smaller cycles do not exist? No. I think there is a consensus for solar minimums (Oort, Wolf, Sporer, and Maunder) causing numerous smaller climate coolings in the last 1500 years. http://en.wikipedia.org/wiki/Sporer_Minimum CO2 levels during the previous glaciation were around 180 ppm but jumped to 280 ppm as we entered the Holocene interglacial. It is now over 380 ppm and I get the feeling that our environment is now immune to future solar minimums. The ice cores also tell us that higher temperatures are always associated with higher levels of CO2. So rather than inspecting charts of "global average temperatures" maybe we should focus a little more on the Keeling Curve. http://en.wikipedia.org/wiki/Keeling_curve -
Berényi Péter at 21:07 PM on 18 June 2010Astronomical cycles
#0 Posted by Riccardo at 07:37 AM More generally, for n=4 the claimed 60 year cycle seems to vanish after the peak at year 1940. It's not to say that the n=4 trend has more value than the n=2, but in the end we can say that the nice cyclic behaviour seen in fig. 1 depends on the choice of the trend function. It's worth to recall that its choice is arbitrary, no physics behind it. Scafetta might not have provided physical explanation for his choice of n=2, but we can give it a try. If the long term trend described by the polynomial fit is supposed to be a response to the gradual buildup of CO2 in the climate system, and we also accept CO2 can be readily translated to "forcing" (two big IFs, but they are consistent with the mainsrteam consensus), we can make an educated guess about the correct form of the trend; not in detail, but at least about the order of polynomial to be used. CO2 increase was more or less exponential starting around 1850 while "forcing" (the resulting radiative imbalance at TOA - Top of Atmosphere) is proportional to its logarithmic concentration. Therefore this forcing has increased in a roughly linear manner since 1850. For a small forcing the climate system response can be considered linear. Any reasonable dynamic system should behave like this except for states close to some singularity. However, as climate during the last several thousand years have not shown wide fluctuations and we are still not very far from the average of this timespan, no singularity of the system can be too close to the present state. If the response of a linear and time-shift invariant system starts out as x4 for a linearly increasing excitation beginning at some instant (in this case in 1850), then its response to a step function starts as a cubic and for a Dirac delta (a brief pulse) it is quadratic. I am not talking about "climate sensitivity" here, that would involve the long term relaxation properties of the response function, it is all about the initial phase. Now. Imagine there was a general balance between incoming SW and outgoing LW radiation at TOA, so the overall balance is neutral. Then, for a brief period (let's say a month or so) this net balance is disturbed, the difference between ASR (Absorbed Shortwave Radiation) and OLR (Outgoing Longwave Radiation) increases substantially, then it is reset to zero again. How does the temperature response look like? The key point is that incoming radiative energy, if not reflected immediately back to space gets thermalized soon. If this excess heat is to stay in the system for a while, it has to be stored somewhere. But there is no other way to store it than heating up some part of the system. As there is no substance around with infinite specific heat, it implies an instant temperature increase. However, a quadratic starts from zero and for a while lingers in its vicinity. The initial phase of the impulse response can't be a quadratic, not even linear. It should start with a step. Therefore response to a linearly increasing CO2 forcing can only increase as xn if n is not greater than 2. I am not saying Scafetta's astrological speculation makes sense, but it can not be rejected on the ground stipulated by Riccardo. You have to find another way to debunk it. Of course, as always, there is an alternative. If the underlying trend is not driven by CO2 but by some other secular change capable to increase its forcing in a cubic (as opposed to linear) rate, Scafetta is debunked for good. However, the very existence of this mysterious agent is an immediate death blow to consensus climate science, so if I were you, I would not take the tack. -
Ken Lambert at 20:58 PM on 18 June 2010Astronomical cycles
Chris #39 Each 'well established' forcing must be looked at in detail - and those from Fig 2.4 of IPCC AR4 are not all that well established. Dr Trenberth's 0.9W/sq.m TOA imbalance is derived from "MODELS" - not direct measurement and in particular cooling forcings have wide error bars. With little storage in the atmosphere, the integral WRT of the energy flux imbalances ie. heat energy, must show up in the oceans. Chris, this “nice AGW trend” is not looking so nice when the purported energy flux imbalances are not showing up in OHC for the last 6 years and probably not much in the last 16 years. Unless this 'imbalance' heat shows up in the oceans; warming is not happening and AGW theory is in serious doubt. -
DrTom at 20:50 PM on 18 June 2010Andrew Bolt distorts again
Whew! What an awful time to be a climate scientist. The top is spinning down but it still wobbles through equilibrium on every rotation. Then it drops a bit and the climate deniers can absolutely get good data that there is no warming. Another half-cycle and it comes across equilibrium...but on the way UP, AGW scientists can absolutely qualify and quantify the shift. Both groups can obviously back-trend and find something. Humans are good at that. The only proof that anyone will ever accept...and many probably won't... is the Venus Syndrome. When climate forcing tips us into a continuous and irreversible feedback loop. What will the precursor to that look like? What marker will unequivocally show the end of our ability to stop our own extinction event and grasp that it has begun? I believe we are there, but I am not the Oracle of science. Yet there must be something specific we can recognize and leave debate mode for an attempt at survival. -
chris at 19:13 PM on 18 June 2010Astronomical cycles
HumanityRules at 15:05 PM on 18 June, 2010”I'm interested in the HADCRUT3 data in fig2. It overall trends up but with periods of rise/fall/rise/fall/rise. Is this not real? Does that need an explanation? This is surely an up trend with a cycle? if not what is the alternative explanation for the phases? Surely this is what AGW wants? An a clean uptrend that mirrors the uptrend in CO2 emmissions? Surely AGW wants to remove the mess of interferring factors (such as solar,volcanos and cycles) to leave a nice AGW trend?”
So many question HR! But you’ve had them answered before I think. The 20th century warming trend can be addressed in the manner you speak of, in two essentially equivalent ways by considering the physics involving known forcings and internal variability. Thus one can independently assess the natural contributions to the 20th century and contemporary warming profile and subtract these from the warming profile “to leave a nice AGW trend”. If one does that, then according to Swanson et al (2009) [*] “Removal of that hidden variability from the actual observed global mean surface temperature record delineates the externally forced climate signal, which is monotonic, accelerating warming during the 20th century.” The other means of doing this is to model all of the contributions to the 20th century warming profile by parameterizing their contribution according to best estimates using known physics, and assess the extent to which these reproduce the warming profile. A couple of examples of this approach can be found here [**] and here [***]. In this case the “nice AGW trend” is established first according to known physics and included in the model, rather than "falling out" of the model as a remainder left over after removing all the contributions from internal variability a la Swanson et al.. In all of these cases the essential features of the 20th century and contemporary warming can be understood in terms of rather well understood natural and anthropogenic contributions. It’s not obvious how another phenomenological numerological analysis that lacks a basis in physics and that doesn't anyway match the empirical data very well is going to add to our understanding. That's not to say it isn't interesting. But fundamental scientific steps are missing here, namely (i) a mechanism for the supposed effect, (ii) its independent quantitation, and (iii) some physical explanation of how this "over-rules" all the known physics otherwise described in the papers cited here and elsewhere. [*] K. L. Swanson et al. (2009) Long-term natural variability and 20th century climate change. Proc. Natl. Acad. Sci. 106, 16120-16123. (see also) Zhang, R., T. L. Delworth, and I. M. Held (2007), Can the Atlantic Ocean drive the observed multidecadal variability in Northern Hemisphere mean temperature? Geophys. Res. Lett., 34, L02709 [**] Hansen, J. L. et al. (2005) Earth's energy imbalance: Confirmation and implications. Science, 308, 1431-1435 [***] Lean, J.L., and D.H. Rind, 2008: How natural and anthropogenic influences alter global and regional surface temperatures: 1889 to 2006. Geophys. Res. Lett., 35, L18701 -
Marcus at 16:58 PM on 18 June 2010Astronomical cycles
HR, that still doesn't change my original point which is this-*if* the Astronomical Cycles Scafetta refers to have acted on the climate before, then we should see *evidence* in the climate record to support it. Now we *do* see evidence of past warming, but this warming was primarily underpinned by a change in the level of Insolation-whether due to increased solar activity (such as the Roman Warm Period & the MWP) or the Earth traversing slightly closer to the sun (the various interglacials). Now if planetary alignments were the actual cause of the change in solar activity, then we'd expect to see increasing solar activity in the current "cycle"-yet the truth is *we're not*-solar activity peaked in the 1940's & has been gradually trending downward ever since. Until someone shows me the some outward *sign* that the sun is being directly impacted by planetary alignments, then Scafetta's work is just an intriguing exercise in mathematical formulations-it most *certainly* isn't a valid explanation for the vast bulk of late 20th century global warming. -
Riccardo at 16:53 PM on 18 June 2010Astronomical cycles
HumanityRules, I did not proposed a different mathematical game, I intentionally played the same game as Scafetta to show its inherent weakness using his own rules. As for the rise and fall, they're real and the widely accepted explanation is (roughly) that it's the sun plus volcanic activity (which no one want to disregard) with anthropogenic forcing dominating the final rise up to today. Disproving this explanation is what Scafetta was trying to do, unsuccessfully in my opinion. As for variability and apparent cycles, it's well assessed that a good part of the measured variability is due to ENSO, a cause of cyclic variability no one overlooks. Once it's effect is removed not much is left and no evident cycles can be spotted. shawnhet, if you assume the reality of the 60 years cycle and fit trend plus the cycle to the data you indeed have good reason to trust it. But the existence of the cycle is what he was trying to demonstrate, it's a tautology to assume it's real to demonstrate that, well, it's real. Indeed, Scafetta correctly first fitted his parabola and then the cycles keeping the parabola fixed. He did not explicitly said he did it this way, I found out empirically. -
Stephen Baines at 16:16 PM on 18 June 2010How climate skeptics mislead
BP "In science the standard practice is to get rid of uncertainty by improvements to your measurement system, postponing your judgment until the job is done." The key question here is what exactly is the "job to be done." One level of certainty is needed to know if an increasing trend in temp exists and another to know whether the increase is quantitatively similar to a known energy imbalance. But obviously we will never know "exactly" what the change in land or sea surface temp is. Even though we believe an exact number actually exists, we can only approximate it. Should we then say we know nothing? The closest thing in the natural (as opposed to mathematical) sciences to the deduction that BP craves is what Platt called strong inference. It involves developing a suite of alternative hypotheses that at least try to address a phenomenon from all sides and then constructing (and conducting) focused experiments to determine which among them hypothesis describes the phenomenon of interest. It's the closest to what BP would recognize as deduction - defining a range of possibilities that encompasses all possible outcomes and evaluating which provides the more probable fit to the data. In some ways we have a perfect set up for strong inference in the case of AGW. AGW provides a coherent explanation for changing climate patterns over the last 50 years that is based largely (although not exclusively) on CO2. The models developed seem consistent with climate changes in the deep past and interaction between atmospheric composition and climate on other planets. Thus we have a body of theory about drivers of climate and a prediction (actually many if you consider the various models) for the future. There are also competing explanations (it's the sun, its PDO or El Nino, its UHI effect) that tend to make somewhat different sets of predictions by emphasizing specific aspects of the energy/climate system. It would be immensely interesting to run an experiment to determine which is the winner here. Of course the problem is that we can't actually control what happens next, we don't have replication, and we don't have a control. What's more we don't actually want to do the experiment if it turns out a certain way, as we are part of the experiment. So the question is, which treatment should we do given that we have one replicate, and we're living on it. We really have no choice but to place odds on which hypothesis is likely to make the best prediction so that we can avoid, or plan for, the possible consequences. That means assessing the relative merits of the different hypotheses up until now. As a scientist I appreciate BPs insistence on precision and his skepticism, extreme as it is. However, if I'm laying a bet that I don't want to lose, I will use all the information available to me to make the best decision. Because AGW provides a very complete explanation of changes to a wide range of variables, it seems a good bet to me compared to the others, most of which were discarded long before they were raised from the dead again...and again. I have to go on a research cruise for a month so I'll be signing off for a while. It has been a pleasure to read all these cogent and mostly civil discussions. Don't have too much fun while I'm away! -
shawnhet at 15:37 PM on 18 June 2010Astronomical cycles
Just so I am clear here - am I supposed to understand that regardless of the exponent of n, we would still be left with some version of the underlying SCMSS cycle that was found by Scafetta? If not, isn't this analysis a trifle incomplete? If Scafetta's detrending plus SCafetta's cycle match up pretty well with the observed temp records, then that is a decent reason to use it as a basis to predict future temps. However, detrending without an explanation of the causes of changes in the detrended data doesn't tell us much of anything. Cheers, :) -
HumanityRules at 15:05 PM on 18 June 2010Astronomical cycles
33.Albatross I think I accepted that the IPCC says 1950 onwards is most, it's 1970's onward were they suggest almost all. So nature has a nett cooling affect for the past 50 years? So the IPCCC does seem to completely reject the presense of 60 years cycles with 1970-2000 being the up stroke of the cycle? It seems this article is suggesting that in playing a mathematical game Scaffetta is identifying a cycle, it should equally be stated that Riccardo is questioning this with his own little mathmatical game. I'm interested in the HADCRUT3 data in fig2. It overall trends up but with periods of rise/fall/rise/fall/rise. Is this not real? Does that need an explanation? This is surely an up trend with a cycle? if not what is the alternative explanation for the phases? Surely this is what AGW wants? An a clean uptrend that mirrors the uptrend in CO2 emmissions? Surely AGW wants to remove the mess of interferring factors (such as solar,volcanos and cycles) to leave a nice AGW trend? -
scaddenp at 14:59 PM on 18 June 2010Astronomical cycles
'So what you're saying is that it is controversial that the 20th century is made up of 60years cycle with an underlying up trend? I can see it's a short time period to recognize a cycle'> Of course I its controversial. Its not controversial that trend is overlaid with ENSO quasi-periodic cycle. McLean et al kindly showed that you can explain much of the cycle that way. But a longer term cycle? Nope. The alternative explanation that it is response to forcing make more sense physically since no natural cycle in energy flow has so far been discovered. Perhaps also look at this Cyclical? -
Albatross at 14:25 PM on 18 June 2010Astronomical cycles
Humanity Rules @32, "At risk of repeating myself it seems the IPCC rule out any component of the 1970-2000 temperature trend being part of a natural cycle." Not true. From the IPCC, AR4: "Most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic GHG concentrations.[7]" Also, "it is extremely unlikely that global climate change of the past 50 years can be explained without external forcing and very likely that it is not due to known natural causes alone. During this period, the sum of solar and volcanic forcings would likely have produced cooling,..." Also, read this There is more in the Copenhagen Diagnosis. Also consider this new paper -
HumanityRules at 14:00 PM on 18 June 2010Astronomical cycles
scaddenp So what you're saying is that it is controversial that the 20th century is made up of 60years cycle with an underlying up trend? I can see it's a short time period to recognize a cycle and confused by other factors but I had it in my head that wasn't controversial. The HADCRUT3 data in fig2 seems to show rise/fall/rise/fall/rise (with an underlying up trend) NewYorkJ I was referring to the IPCC's statement on post 1970's data. If late 20th century is almost all AGW then there is no room for an upstroke on a natural cycle as suggested by figure 1. Marcus I did say natural cycle with an overlying trend and Scaffetta detrends the data for a reason. I think one of the questions raised by this is not if all the late 20th warming can be explained by natural cycles but whether we need to unpick the complex factors affecting the global temperature. At risk of repeating myself it seems the IPCC rule out any component of the 1970-2000 temperature trend being part of a natural cycle. -
ginckgo at 13:38 PM on 18 June 2010Peer review vs commercials and spam
Oh dear, more assertions that peer review reinforces the 'consensus', that reviewers abuse it to keep rival interpretations out to corner grant money, or that they bow to the opinion of 'powerful personalities'. FYI, there is no group that love a proper controversy more than scientists. And by 'controversy' I don't mean fake ones like Creationism vs Evolution. They are inherently anti-authoritarian, and while most students probably start out thinking their supervisor's interpretations are perfect, by doing their own research they soon figure out that they're not. -
KR at 12:46 PM on 18 June 2010How climate skeptics mislead
Berényi - you continue to confuse probability theory (known universe of results, absolute identification of each case, and the likelyhood of one result from that limited known universe) with the first definition of probable, supported by evidence strong enough to establish presumption but not proof (a probable hypothesis). You have also not, as far as I can tell, read either e's or my links to inductive arguments, the basis of (to list a few) climate theory, evolution, and most of our every day decisions - not to mention how we judge competing theories every time they arise in science. We can't know all possible outcomes; we have to decide based on the strongest evidence and experimentation we have. I will be the first to admit that inductive logic is a point of contention. Every philosopher of science who has written on the subject has concluded that (a) it's not absolute proof, or an absolute conclusion, as deductive logic provides, and (b) bloody hell, we need it anyway, since we cannot know all cases, and must make decisions based on whatever experimentation we have been able to conduct - without knowing the entire universe of results. Most people take an inductive theory, and apply deduction to support it - there's rarely an acknowledgement of the inductive basis of many of the premises used in the deductive arguments. Irregardless: As I stated quite some time ago, on a completely different focus, even if your objection to the GHCN data is valid, a point of some contention, that does exactly nothing to disprove the many many other independent lines of evidence that support global warming and indeed AGW. In fact, this is now a poster-child demonstration of the skeptic approach of picking one line of evidence, bringing up some objection (of varying strength), and then stating that based on that singular objection to a particular data set that an entire theory supported by many lines of evidence is now suspect - that all supporting lines of evidence/data sets (such as the several satellite sets you refer to) are therefore invalid. Just as John Cook described in this topic, at the top of the page! Issues with a single line of evidence are limited to that line of evidence, and only propagate to derived data - and the satellite data sets are very clearly not derived from the ground station data. Single data line issues don't affect a general theory unless a significant number (again, a judgement call) of the supports for that theory are invalidated, or that a better explanation (simpler? parsimonious? Fewer crystal spheres?) is found for them. Thank you for the demonstration, Berényi. -
Berényi Péter at 12:31 PM on 18 June 2010How climate skeptics mislead
#203 Tom Dayton at 11:31 AM on 18 June, 2010 At least, you were wrong if you continue to insist that scientific decisions are binary, so that "postponing judgment" means refusing to make a decision at all until, when you have removed all uncertainty from your measurements, you make your decision with 100% certainty. John, who said all uncertainty should be removed from measurements? That's not even possible. On the other hand if uncertainty of judgment is due to poor measurability, of course it is the first thing to do to improve measurement. You know perfectly well that you do not have to remove all uncertainty from measurements to be able to form true propositions. If you measure the diameter of a speck and find it to be 1 cm, measurement error is 10%, you can be certain the speck is smaller than 1 km, can't you? On the other hand if you measure 973 m, you have to have a closer look and refrain from judgment until it's done. It is perfectly legitimate to say I-do-not-know. And yes, a scientist do not have to make public decisions. It is not his job. Otherwise of course he makes decisions all the time as anyone else. But there is nothing particularly scientific in them, not even in the case he makes a decision on performing a specific experiment. -
Albatross at 12:27 PM on 18 June 2010How climate skeptics mislead
BP, "What kind of question is that? Some obviously do. Others not. The same with non-skeptics." A reasonable and relevant question. Let me put it to you this way. Do you approve of the propensity of "skeptics" to distort, misrepresent and confuse the science of climate change? Monckton being one example. So please elaborate on your stance. I would take issue with your use of the quantifier "some" when referring to skeptics misleading. Have you not been paying attention to the content posted at "skeptical" sites such as WUWT, or the distortion but certain media outlets of late? There is a definite propensity for skeptics to intentionally mislead or embark on sub-par science. In fact, there are simply too many examples to cite here. There is also a definite tendency for "skeptics" to try and distract attention from the compelling convergence of multiple lines of evidence in the post by John. That point is clearly irksome for "skeptics", so it seems their tactic is to distract or obfuscate, and I might add that has been beautifully illustrated by the wayward discussion of the UHI on this thread (that being but one example). "e" at 202, fair enough :) Are you or anyone else here familiar with the work of Giere, specifically his book "Understanding Scientific Reasoning"? BP, maybe something to you to consider reading? -
Marcus at 12:01 PM on 18 June 2010Astronomical cycles
HR, if the last 60 years is all part of some natural cycle, then we should be able to detect identical trends during previous 60 year cycles. The reality is, though, that we can't. By Scafetta's analysis, the last 60 year cycle was 1890-1949, but I've already shown how-in spite of a large growth in average sunspot numbers-the rate of warming was only +0.06 degrees per decade. Compared to +0.11 degrees per decade for 1950-2009, in spite of a fall in sunspot numbers over this time period. That suggests to me that something other than natural cycles is at work! -
How climate skeptics mislead
BP, the lofty traits you ascribe to science apply only to formal logic and mathematics. Perhaps science is not what you thought it was? Many philosophers to this day have grappled with the problems with science you discuss. In my mind, the only reason necessary to trust in such a vague and uncertain endeavor is that it works. Planes fly, cars drive, diseases are cured, etc. -
Berényi Péter at 11:32 AM on 18 June 2010How climate skeptics mislead
#199 Albatross at 09:49 AM on 18 June, 2010 please, at least have the gumption to call foul when "skeptics" mislead Foul. Or do you disagree with John's (and others') assertion that "skeptics" mislead? What kind of question is that? Some obviously do. Others not. The same with non-skeptics. -
How climate skeptics mislead
BP >It is made to look scientific while in fact it is just plain old-style guesswork. Yes it is guesswork BP. But it is an educated guess. This is how predictive science works my friend. We can never know the future with certainty, we can only guess at it based on our uncertain knowledge. -
Tom Dayton at 11:31 AM on 18 June 2010How climate skeptics mislead
Berenyi Peter, you were wrong in stating that "In science the standard practice is to get rid of uncertainty by improvements to your measurement system, postponing your judgment until the job is done." At least, you were wrong if you continue to insist that scientific decisions are binary, so that "postponing judgment" means refusing to make a decision at all until, when you have removed all uncertainty from your measurements, you make your decision with 100% certainty. Science never has worked that way, and it cannot work that way. Not in any scientific field. Uncertainty of measurement never can be reduced to zero. More importantly, fit to measurements is not the only criterion by which scientific theories are evaluated, and evaluating by using that whole cluster of criteria is a complex human judgment that involves yet more uncertainty and, inescapably, more or less subjectivity. I am a trained scientist, as are many of the posters and commenters here. Your insistence that you are the only one who knows the definition of science has become annoying rather than being simply naive. You don't have to trust our assertions. Just read good science journalism, such as Science News or Scientific American. In nearly every story you will see a range of opinions from scientists who are specialists on that topic. Some even claim to be 100% certain that the theory is correct, whereas others say they are "pretty sure," some say their certainty is 50%, and often there are others who insist they are 100% certain that the theory is wrong! And every time there is a discovery or theory that "overturns" a field, that means the majority of scientists in that field previously were certain about something they now are certain is wrong! You also wrote "In real life this procedure is not always practicable, because decision is urgent and resources are lacking. In this case you have to make-do with what you have. But do not call that science please." But science is "in real life"! Science always requires decisions, even if those decisions are whether to continue to try to validate a theory or abandon it--whether to do one more experiment or analysis despite the counter-evidence or lack of evidence that has been gathered so far, whether to even spend more time thinking about it! There is a range of "urgency" and a range of "resources," so you are correct only insofar that in some cases the "decision" about a theory (or even whether to trust an observation) is an armchair kind of decision. In those cases, scientists do indeed officially reserve judgment. But in practice they actually do make decisions about whether to continue to investigate, and rarely will they refrain from passing judgment at all; instead they will state a judgment with caveats. Science is what scientists do. You should read more about philosophy and history and sociology and anthropology of science, and even more than just Popper's opinions. Scientific decision making and probability are merely subsets of the topic of judgment and decision making, about which you need to learn; try, for example, David Hardman's book. (I apologize if this comment is too long or strident. I take the coward's way out by blaming a glass of Moylan's "Kilt Lifter" Scottish style ale.) -
How climate skeptics mislead
Sorry Albatross I agree this conversation has taken some esoteric turns, but since the theme of this post is the "consensus of evidence", I feel that a philosophical discussion of why such a consensus has relevance is somewhat on topic. In any case I can't help myself but indulge BP in this discussion a little bit more, I apologize if I'm just running in circles here. I think it's pretty clear he disagrees with you by the way that skeptics mislead. BP feels that a focus on minute particulars is far more relevant than weighing the totality of evidence. I'll defer to John's judgement as to whether this conversation needs to end where it stands. BP, That was a very interesting post, but it only serves to weaken your own arguments. You write that often in science we start with a huge inductive leap, then work backwards deductively establishing evidence for the general principle. I'll agree this is often the case, but not with climate science. AGW fell out of an attempt to reconstruct the behavior of our climate from our low level understanding of physical processes. It is clearly a theory borne out from inductive methods. Early attempts did try to deduce our climate's behavior from broad generalizations, but these attempts were met with failure (take a look at that link, it's a good read if you haven't seen it already). Furthermore, in your own entreaties you have urged us to stop looking at the "big picture" and working backwards, rather you'd prefer we work out the individual pieces and see where it takes us. You propose a method that is clearly inductive when applied to the general theory of AGW. Why then can we not evaluate your approach as such? > We can never be sure if these signs give us truth or not. However we have no choice but consider them true until proven false (by experiment or observation). Utter nonsense BP. You are now in direct contradiction to the basic principles of scientific skepticism (and of course, all modern judicial systems). Positive claims require positive evidence before we even entertain the idea that they are true. I propose to you that there is an invisible unicorn standing behind you right now. Did you honestly have to wave your hands in the air before assuming that my claim is false? >If something is 95% true, it may take quite a lot of counterexamples to get one convinced it must be false after all. Yes. This is exactly how the scientific method is supposed to work in fields where the evidence itself is complex, and is perfectly consistent with how theories have historically been modified or replaced. In such fields, each piece of evidence standing on its own is questionable. Only when you take the evidence in summation does a case for general theory arise. If a single piece of complex evidence can unambiguously falsify a theory, then I again submit that observations of SST's falsify your claims on UHI. >we are doing science and in this fine tradition you should let your communication be, Yea, yea; Nay, nay: for whatsoever is more than these cometh of evil. That communication has been a direct and clear "YES": based on the mass of all current evidence, AGW is true. It is the "skeptics" that have harped on the question of uncertainty. >In science the standard practice is to get rid of uncertainty by improvements to your measurement system, postponing your judgment until the job is done. There is no such thing as "getting rid of uncertainty" in science BP, I thought we had established that fact already. As such, the "job" is never complete and your claim implies we will never make any judgements whatsoever. If you honestly believe there is such a thing as 100% certainty (the equivalent of saying all uncertainty has been removed), then there is no point in continuing this conversation. -
Berényi Péter at 11:13 AM on 18 June 2010How climate skeptics mislead
#183 doug_bostrom at 11:40 AM on 17 June, 2010 It seems to me that overzealous application of Kolmogorov's axiom system could lead us to effective paralysis Yes. In real life it is imperative to be able to handle obscure issues. However, the way we do it should not be confused with applications of probability theory in the strict scientific sense. This is exactly the problem with the way IPCC presents its assessment system with guidelines for quantification. It is made to look scientific while in fact it is just plain old-style guesswork. Insufficient knowledge of sample space (field of possible events) is a serious issue. There are several extremely complicated systems like commercial airplanes or nuclear power plants where failure is not tolerated easily. Guys are developing sophisticated models to assess probability of failure but the thing is, retrospective analysis of actual accidents almost always uncovers some momentum or coincidence of otherwise independent chains of events, that no one expected, therefore it was missing from any previous risk assessment scheme as well. The rule is rare events happen often. There is an enormous tail of the probability distribution spanning unexplored expanses of the sample space. In this region each individual event has a vanishingly small probability, but all taken together, some of them is to be expected to happen rather soon. There is no good scientific way to handle situations like this. You have to rely on structural safety, engineering expertise, responsibility and common sense. There is another issue. This is personal communication from a guy trading in Decision Theory. In fact it happened in a pub, drinking beer, so I don't have references. Anyway, he described an experiment where subjects were asked to play a game and they were actually payed some small money for winning. There were a dozen or so marbles, all yellow, except one, which was blue. These were put into a black velvet bag in front of the subject, so he could see and count them. Then the experimenter pulled the marbles out of the bag one by one and the subject was to bet on its color in advance. Later on the betting strategies people followed were analyzed. There is a known optimal strategy for this game and it was found their performance was seriously suboptimal. The guy (the one I was drinking beer with) wondered why was it so. Well, there was a quirk to the experiment. The black velvet bag had a small hidden pocket inside and the experimenter trained himself in advance to be able to put the blue marble into the pocket in plain view without being noticed. This way he could always invariably present it on the last turn. It made sense, because this way he had more data (as soon as the blue marble is out, there is no uncertainty left in the game whatsoever). I told him the subjects probably guessed he was cheating on them and adjusted their strategies accordingly. He thought he had taken all the necessary precautions to prevent this, each subject played the game only once, they were not allowed to communicate with each other, and he, being an amateur magician otherwise, could really perform the cheat undetected. Well, I told him people have a general knowledge of psychologists cheating in experimental situations like this, so he has to look for the specific cheating model people had in their mind making the betting strategy they have actually followed close to optimal. So did he. Not in the pub, but during the days following. Next week he came up with a probability distribution for the blue marble along consecutive turns that made the average observed strategy optimal. It was tail-heavy, that is, looked like some mixture of the correct uniform distribution and the actual one, where the blue marble was always the last one. He could not repeat the experiment without cheating, because by then it was common knowledge among the students that the last one is blue. No one knows what has actually happened. There is a small possibility of the subjects communicating their experiences to the ones still waiting. But the distribution has not looked like that. It didn't have a single spike at the last turn, but a rising slope. People may be too dumb for this game. But it is also possible the sample space they had in mind and on which they have (mostly unconsciously) computed their strategy was wider then it was supposed to be and on top of possible configurations of marbles also included guesses on ways they might be cheated on. After all it can happen anytime, not only in controlled experimental situations. There are more things in heaven and earth, Horatio, Than are dreamt of in your philosophy.
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