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Comments 41601 to 41650:
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saileshrao at 02:21 AM on 9 October 2013A rough guide to the components of Earth's Climate System
Re: "the fastest carbon dioxide sink - plantlife - is also carbon-neutral; plants take it in but re-release it when they die and decompose, which is an effectively continual process, recycling a lot of carbon dioxide all the time."
I respectfully disagree with this statement. Surely the Sahara desert does not sequester as much carbon as the Congo or the Amazon forest per unit area? Indeed, regenerating forests is the quickest way to sequester the excess carbon in the atmosphere and it is time that the scientific community wake up to it.
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John Mason at 02:02 AM on 9 October 2013A rough guide to the components of Earth's Climate System
All well and good, WHT, but how the **** is a newcomer to climatology going to understand a single word of what you have just written?
Bear that in mind, and consider that this post has fortuitously turned into an online workshop on effective climate change communication, where the best way of stating the facts is being crowd-sourced. Now, how to put that to a beginner?
There were a number of errors/poor ways of stating things in the original post that I have attended to. Let's continue to explore that, because whilst much of the rest of the post is accurate, I'm always looking for new ways to explain stuff more clearly, and the best way of learning how to do that is to look for criticism.
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JasonB at 01:48 AM on 9 October 2013Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
BTW, to illustrate the perils of using short time periods, the HadCRUT4 trend for 2010-2012 is -1.242 ±1.964 °C/decade. Plotting the central trend on Fyfe et al's Figure 1 would put it far off the left of the chart. Would this prove that there was a problem with the models? Or that perhaps the time period is just too short to reach definitive conclusions?
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rocketeer at 01:45 AM on 9 October 2013SkS social experiment: using comment ratings to help moderation
The rational arguments being advanced here as to how users might apply a rating system belies the reality of how actual real-world users on un-moderated comment boards (cough-Yahoo-cough) use the ratings. Highly motivated political ideologues on both sides, but especially among the ultra-right will vote down each and every post by anyone who disagrees with them. Respectful, knoweldgable posts citing references are likely to get a disproportionalte share of thumbs down while arrogant, snarky and factually incorrect rants are enthusiastically up-rated. The bottom line is that climate deniers are not interested in having an intelligent discussion of the issue any more than drunken soccer hooligans are interested in a cogent discussion of the weak points of their team. We should probably just be thankful that they can't start fist fights in the parking lot.
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JasonB at 01:44 AM on 9 October 2013Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
I wrote:
Contrast this with the SkS Trend Calculator (which uses the method of Foster and Rahmstorf 2011) that gives a 2σ trend of 0.177 ±0.108 °C/decade for the former and 0.080 ±0.161 °C/decade for the latter.
Sorry, accidentally used GISS. The HadCRUT4 figures are 0.155 ±0.105 °C/decade and 0.052 ±0.155 °C/decade, respectively.
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ajki at 01:43 AM on 9 October 2013SkS social experiment: using comment ratings to help moderation
Personally, I don't think a mere up/down-voting can do any good (to quality, behaviour, "culture" of a discussion/web page). Beside typical problems of web based voting systems (gaming the system, something that may well get the moderation from a "tiresome chor" to a complete and enduring hell!), these systems may be well suited for opinion based forae or "taste" orientated ( ;-) ) sites, but far less for a site dedicated to the (let's call it) veracity of arguments.
There are websites where working complex voting systems, based on deliberately chosen rules, generate a user moderation of comments (slashdot comes to mind) and which are doing a good job on that - at least on behalf of nature of those sites. But those sites are out to generate a general culture for that special place, something that often leads to the "hivemind" and should be avoided on scientific websites at all costs.
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JasonB at 01:35 AM on 9 October 2013Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
adeptus,
I haven't read Fyfe et al but looking at their Figure 1 you presented it strikes me that (a) the error margins on the HadCRUT4 trends are very narrow and (b) both 1993-2012 and 1998-2012 HadCRUT4 trends seem to have the same width.
Contrast this with the SkS Trend Calculator (which uses the method of Foster and Rahmstorf 2011) that gives a 2σ trend of 0.177 ±0.108 °C/decade for the former and 0.080 ±0.161 °C/decade for the latter. (And note that the trends calculated by the Trend Calculator do not take into account the fact that the start date is cherry picked, which 1998 almost certainly is.)
If the red hatched area in Figure 1a went from 0.069 to 0.285 °C/decade then it would cover about half the model trends; likewise, a red hatched area of -0.081 to 0.241 °C/decade in Figure 1b would cover about 2/3 of the model trends.
I think the reason for the differences in trend uncertainty is because Fyfe et al aren't trying to determine the true underlying long-term trend (which the SkS trend calculator is trying to determine) but rather they are assessing whether the models have accurately captured the short term variability with a view to seeing what is to "blame" (e.g. ENSO, aerosols, etc.).
As mentioned by Albatross here, Box TS.3, Figure 1a from AR5 looks to be the same as Figure 1b above:
Note that from 1984-1998 those same models underestimated the warming trend (1b). Yet from 1951-2012, they did a really good job indeed.
Therefore we can conclude that over short periods of time the models don't necessarily predict the actual, observed trend very well, but over long periods of time they do exceedingly well — and since what we're worried about is the long term effect, and not what the temperature is going to be next year, this is important. Also note that if you calculate the uncertainty in that observed trend to see what the range of possible values are for the underlying, long-term trend, there is a great deal of overlap even in shorter periods.
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Paul Pukite at 01:17 AM on 9 October 2013A rough guide to the components of Earth's Climate System
The issue of residence time versus adjustment time is that permanent sequestration of CO2 is not a first-order uptake process which leads to a damped exponential response. Instead, it is a diffusional response which leads to fat-tails in time. Diffusional responses are very common in physical systems, including related climate domains as ocean heat uptake.The Bern model of CO2 sequestration models the fat-tail diffusional response by a linear combination of damped exponentials with a range of time constants.I think the real issue is that no one seems to want to call it a diffusional response, which leads to the endless confusion and why deniers still refer to the Segalstat misinformation. This as recounted by McInt:"Segalstat of Oslo University led off the afternoon with a general, and, as far as I can tell, uncontroversial exposition of the carbon cycle, but closed with the well-known cartoon showing the correlation between change in bathing suits from bloomers to thongs and global warming. At this point, Bert Bolin exploded at Segalstat (who apparently is a former student of Bolin’s) saying that he needed to read a text book. Bolin announced hat he was leaving the conference because it was such garbage. After some efforts to restore order, Bolin sat down for a few minutes and then left, still without paying his entrance fee." -
Dan Olner at 01:12 AM on 9 October 2013SkS social experiment: using comment ratings to help moderation
Sorry to comment again: I've just seen your hover text - good idea. Can I suggest an alteration? Don't have it float with the mouse, just float it to the right of the arrows when you hover, but with a link saying something like "click here to read the factors we'd like you to consider before using the thumbs up/down arrows".
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Dan Olner at 01:10 AM on 9 October 2013SkS social experiment: using comment ratings to help moderation
How are you proposing to keep posters in line with your list of factors? Will new registerees have to view a web-page telling them what factors to consider? Without making sure all new commenters are aware of them (and even then perhaps) people will just default to "thumbs up/down = I likey / I don't likey".
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Leto at 00:51 AM on 9 October 2013A rough guide to the components of Earth's Climate System
Thanks John, I much prefer the new wording re residency time.
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Leto at 00:44 AM on 9 October 2013SkS social experiment: using comment ratings to help moderation
Sphaerica,
I agree 100% that, for most of science, truth is absolute (the exceptions are potentially interesting but not on-thread). In fact, I have less sympathy than most for a relativistic view of truth. I actually think that, for most of the contrarians coming here, they only have themselves to blame for being ignorant - I would even say that most contrarians exhibit extreme hubris when they claim to know better than the vast majority of climate scientists, often on the basis of reading anti-science blogs with way too little true skepticism...
But if accuracy is to be a major criterion for clicking the up-thumb, then we would basically be clicking to indicate which camp we are in, and the thumb clicks would then carry very little information. (It almost sounds like single-click sloganeering, to me.) This is directly at odds with the instruction "The point is not to vote up comments that support your position and to vote down comments that support their position."
We already know that comments will, for the most part, be pro-AGW (i.e "accurate") or anti-AGW (i.e. "inaccurate"), so the clicks could end up being a continuous poll of how well each camp is represented in the readership (or clickership, anyway). The clicks won't be able to register any sort of behavioural dimension or reward appropriate behaviour if they are busy performing this fairly facile polling function.
If contrarians come here to engage in honest dialog, and find every one of their comments is heavily down-clicked no matter how well behaved they are, this could undermine the very outreach function the site is trying to achieve.
And note that, by expressing this view, I am not at all suggesting that truth is relative, or that all opinions are equally valid, and no such implication was contained in my earlier post.
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Magma at 00:34 AM on 9 October 2013SkS social experiment: using comment ratings to help moderation
My own view leans towards "if it ain't broke, don't fix it". I suspect most online moderators would confirm that it's difficult to keep out motivated trolls or others who would game a voting system, particularly for something as simple as a click up or down. And as Harry H. (post #4) notes, human nature makes it difficult to separate "I agree" from "well-argued".
Apart from this, early posts will receive more views and more opportunities for votes, up or down, than later ones, regardless of 'quality'. The weight really should go to well-written comments and replies, with moderators able and willing to remove posts that detract from the discussion thread (as this site does). A standard tactic that can be observed on weakly or non-moderated sites is the early hijacking of comment threads, filling them with enough nonsensical or abusive posts that subsequent readers move on rather than comment.
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saladyears at 00:22 AM on 9 October 2013SkS social experiment: using comment ratings to help moderation
Wired had an article up about how some research is happening into making comments sections better places. One of the ideas was to have a "Respect" button instead of Like or +/- ratings. The idea being that people are much more likely to positively rate an opposing argument if it doesn't seem like they have to agree with it. That's what "respect" seemingly does.
http://www.wired.com/design/2013/09/can-you-design-a-website-to-encourage-readers-to-consider-a-different-point-of-view/
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Bob Lacatena at 23:59 PM on 8 October 2013SkS social experiment: using comment ratings to help moderation
Leto says:
As soon as we start to thumb based on what we think of as "true", then we are also voting up comments that support our position.
This begs the idea that accuracy is relative, and that opinions count as accurate facts. Accuracy should not be applied to positions, but it should be applied to facts. If someone says that the globe has been cooling for the past 17 years, that is flat-out innaccurate. If they say that there has been an apparent slow-down in warming for the past 17 years, that is an arguable point and as such not strictly innaccurate.
Facts in this debate are either true, false, uncertain (but that uncertainty is supportable in the peer-reviewed literature), or they aren't facts at all but merely beliefs and opinions.
One of the big problems that false skeptics seem to have is that they are unable to separate fact from belief. They can't see the difference in their own mindset, and then they project that mindset onto others... labeling their understanding of the science as a belief rather than an acceptance of the facts.
There is a distinction, and people should vote according to that distincition.
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ellisr01 at 23:53 PM on 8 October 2013A rough guide to the components of Earth's Climate System
I find the section on the geosphere still suffering from a lack of clarity, but thank you for removing the very confusing point about 5 year residency time. I am of the opinion that a lot of clarity could be obtained by focusing heavily on the root cause of elevated atmospheric CO2: the movement of stored reduced carbon out of the geosphere (lithosphere) for the purpose of harvesting the stored chemical energy and subsequent release of the gaseous oxidized carbon which goes where any released gas will go, into the atmosphere. Describing clearly this one-way, man-made, process with clarity would go a long way towards bringing understanding. It would both explain the fundamental probem and at the same time point out that fossil fuels are non-renewable. This geosphere to atmosphere transfer of carbon is creating a great load on the natural processes that remove CO2 from the atmosphere. The CO2 is "queued up" in the natural CO2 removal process, mainly chemical weathering, is creating all the trouble.
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John Mason at 23:21 PM on 8 October 2013A rough guide to the components of Earth's Climate System
OK DM - could you take a look at the last paragraph of the Geosphere section now I've revised it - is that clearer?
Peer-review live - great fun!!! - but if it improves the end product it is well worthwhile....
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adeptus at 22:44 PM on 8 October 2013Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
I though the science was settled on this issue?
Moderator Response:[JH] You are skating on the the thin ice of violating the following section of the SkS Comment Policy:
- No link or picture only. Any link or picture should be accompanied by text summarizing both the content of the link or picture, and showing how it is relevant to the topic of discussion. Failure to do both of these things will result in the comment being considered off topic.
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chriskoz at 22:33 PM on 8 October 2013SkS social experiment: using comment ratings to help moderation
OPatrick@13,
Think about this case as "something I didn't know about which sparked the discussion & sibsequently the discussion increased my knowledge".
With time, you will learn to distinguish true "skeptical ideas" from longtime debunked trolls and your recommendatrion skill will improve.
I think your desire to make recommendation "more accurate" would complicate the system with little overall benefit in terms of the data John collects from it. If I'm correct with this supposition, then John agrees according to his comment @12: enough value to be worth the complication.
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OPatrick at 22:11 PM on 8 October 2013SkS social experiment: using comment ratings to help moderation
Is there any way of unrcommending a comment you've recommended? I occasionally read a comment and think it's reasonable but later in the comments thread someone gives context which shows that it was not.
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John Cook at 20:35 PM on 8 October 2013SkS social experiment: using comment ratings to help moderation
Thanks for everyone's comments. Re the danger of amplifying the echo chamber, there is a possibility of that but it's not inevitable - it may depend on the specific community and the specific context (e.g., the fact that only registered users can rate, that banned trolls cannot rate, the instructions provided).
Re fredb's comment about comments floating to the top, our system doesn't change the ordering of comments based on ratings. They're still ordered chronologically.
Re Harry H's comment about 2 dimensions of ratings, it's an interesting idea and I am a big fan of collecting more data. However, I'm also a big fan of keeping things as simple as possible. In this case, I think a second dimension doesn't add enough value to be worth the complication.
Leto, if someone is unknowingly repeating a myth, that should earn a down thumb. Determining a person's motives in an online comment is always problematic so we have to take the information at face value.
Scaddenp, will think about whether to add this feature to the Recent Comments page. On the one hand, it's better to see a comment within the context of the comment thread it belongs to. On the other hand, adding the feature to Recent Comments results in collection of more data. Hmm...
Chris S., I see your point about showing the result possibly skewing results. I believe Heisenberg anticipated this in the early 20th Century (you should formalise this as the Chris S Uncertainty Principle). But I think you lose more than you gain by not providing feedback.
John Brookes, I hope you don't try to earn maximum amount of down thumbs at SkS!
Yves, I see the down thumbs as filling the role of an alert button. Well, not exactly but in that general direction.
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Dikran Marsupial at 20:14 PM on 8 October 2013A rough guide to the components of Earth's Climate System
John as residence (turnover) time and adjustment time already have definitions, I think using the phrase "effective residence time" to mean "adjustment time" is likely to further prolong the confusion between residence time and adjustment time that lies at the heart of this myth. It is a shame that the new report uses the phrase "residence time of a perturbation of CO2", which seems to needlessly confuse the two terms slightly.
Leto, I don't think there is any real controversy regarding residence time. It is defined as the ratio of the mass of the atmospheric reservoir (which is known with good accuracy) and total annual uptake from the atmosphere. This is less well known, but a figure of 4-5 years for residence time is generally accepted (see e.g. the glossary of the AR4 WG1 report for "lifetime"). I suspect the residence time is slightly different for different carbon isotopes, but not enough for it to make a significant difference to the bulk residence time of the atmosphere.
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Klapper at 19:57 PM on 8 October 2013SkS social experiment: using comment ratings to help moderation
I was going to make a comment about the "echo chamber" effect, but I see Flakmeister has already beat me to it. I'm not a prolific commenter here, but I think the citations "requirement" is nonsense, particularly since there's a fairly apparent double standard about posting non-peer reviewed references deemed "friendly" (like Tamino, or Tom Curtis), vs. "unfriendly" non-peer reviewed analysis.
Moderator Response:(Rob P) - There is little point in SkS in being like most of the internet - full of unsubstantiated opinion. Peer-reviewed scientific literature is the 'gold standard' not because it is perfect, but because it is research carried out by experts and subject to the scrutiny of other experts. Rubbish still gets through though - Ole Humlum & co-authors, for instance, think human industrial emissions of carbon dioxide magically disappear.
If commenters make claims, they should be able to back it up with facts. We don't think that's unreasonable.
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John Mason at 19:42 PM on 8 October 2013A rough guide to the components of Earth's Climate System
Have added some other useful links regarding carbon sinks in the Geosphere section of the post. Keep the comments coming - the clearer this ends up the better :)
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John Mason at 19:22 PM on 8 October 2013A rough guide to the components of Earth's Climate System
Leto,
Perhaps a better term is 'effective residence time', as individual CO2 molecules are not the big picture. For a discussion of this, see:
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Yves at 19:13 PM on 8 October 2013SkS social experiment: using comment ratings to help moderation
Having some experience with a French information website, I would suggest introducing recommendation only. Thumbs up without thumbs down. Along with an alert button in case of uncivil behaviour. This would be a little more indicative of the added value of a contribution - not intrinsic added value but in the context of the initial article, including timeliness, on-topic,...- with all the unavoidable caveats such as confirmation bias, groupthink,... since any participative website represents some kind of community.
Besides, I would also suggest setting a limit for contributions' length, in order to avoid lengthy rants. In case of a valuable, pedagogic contribution, this limit could be exceeded with editor permission - though a suggestion for editing an article could be welcome. -
Dikran Marsupial at 18:48 PM on 8 October 2013Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
franklefkin wrote "Another thought. Perhaps the route you are suggesting is correct. If that is the case, why would the IPCC use the wrong ranges in AR4?"
The IPCC didn't use the wrong range for the subject of the discussion in the report (and at no point have I suggested otherwise). It just isn't a direct answer to the question that is being discussed here. Sadly you appear to be impervious to attempts to explain this to you, and are just repeating yourself, so I will leave the discussion there.
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John Brookes at 18:18 PM on 8 October 2013SkS social experiment: using comment ratings to help moderation
Having been a regular poster at Jo Nova's blog, where the thumbs up/down have been there for a while, I can say I quite like them.
A quick scan for lots of thumbs down leads me to comments that are more interesting. It also gave me a goal for a while - to try and get as many thumbs down as I could.
But all skeptic blogs seem to be, dare I say, less skeptical these days. Too many gullible skeptics...
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Chris S. at 18:10 PM on 8 October 2013SkS social experiment: using comment ratings to help moderation
Having the scores next to the thumbs may skew the system. People are more likely to attempt to game the system if they can see the results of their actions. I would advocate just having the thumbs if you wanted to see a truer reflection of voting preferences.
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jyyh at 18:01 PM on 8 October 2013SkS social experiment: using comment ratings to help moderation
thumbs up voting button seems to work also.
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jyyh at 17:58 PM on 8 October 2013Arctic sea ice "recovers" to its 6th-lowest extent in millennia
looks like it works. how do I make it go to zero again?
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jyyh at 17:57 PM on 8 October 2013Arctic sea ice "recovers" to its 6th-lowest extent in millennia
just testing the thumbs down voting system...
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JasonB at 17:50 PM on 8 October 2013Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
Following Tom's lead, here is a graph based on my suggestions @ 125:
I have simply taken Tom's graph @ 79 and plotted SASM's minimum and maximum trend lines starting at the same location and using the same slopes that SASM used.
As expected, there are quite a few model realisations that go much further beyond the supposed minimum and maximum than the actual temperature record does.
Given that those minimum and maximum trends were derived from the model realisations, and that applying this technique would lead to the nonsense conclusion that the models do not do a good job of predicting the models, clearly the approach is flawed.
Note also that shortly after the starting date, practically all of the models dramatically drop below the supposed minimum, thanks to Pinatubo! Indeed, at the start date, all of the models lie outside this supposed envelope. Again, this is because trend lines are being compared with actual temperatures.
On a different note:
In each of these cases, model temperatures are being compared to HadCRUT (and sometimes GISS) temperatures.
However, even this is not strictly an apples-to-apples comparison, as has been alluded to before when "masking" was mentioned. AFAIK the model temperatures being plotted are the actual global temperature anomalies for each model run in question, which are easy to calculate for a model. However, HadCRUT et al are attempts to reconstruct the true global temperature from various sources of information. There are differences between each of the global temperature reconstructions for the exact same actual temperature realisation, for known reasons. HadCRUT4, for example, is known to miss out on the dramatic warming of the Arctic because it makes the assumption (effectively) that temperature changes in unobserved areas are the same as the global average temperature change, whereas e.g. GISTEMP makes the assumption that temperature changes in those areas are the same as those in the nearest observed areas.
To really compare the two, the HadCRUT4 (and GISTEMP, and NOAA) algorithms should be applied to the model realisations as if they were the real world.
However, in the current circumstances, this is really nitpicking; even doing an apples-to-oranges comparison the real-world temperature reconstructions do not stand out from the model realisations. If they did then this would be one thing to check before jumping to any conclusions.
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scaddenp at 17:21 PM on 8 October 2013SkS social experiment: using comment ratings to help moderation
No way to vote up or down on the "Comments" stream which is where I would normally read comments. I see the posts on Feedly and I would only go the thread itself when I want to add a comment.
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Leto at 17:02 PM on 8 October 2013A rough guide to the components of Earth's Climate System
John,
Thanks for the post. I am confused on one point - how do you reconcile this statement:
"By contrast, the greenhouse gas carbon dioxide has an 'atmospheric residency' time of many centuries: once up there it takes a long time to get rid of it again."
... with previous discussion of the residence time of CO2 in the recent Essenhigh thread . In the comment section, Dikran Marsupial wrote:
"Essenhigh's 5 year figure for residence time is correct, and indeed agrees with the figure given in the IPCC WG1 report. His error lies in not understanding the distinction between residence time and adjustment time."
I agree that adjustment time is the more important figure, but what is the consensus on residence time for CO2 in the atmosphere? Is there a terminological issue here?
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Leto at 16:48 PM on 8 October 2013SkS social experiment: using comment ratings to help moderation
The post says this: "The point is not to vote up comments that support your position and to vote down comments that support their position."
But then the post also asks us to thumb according to multiple critera including this one: "Accuracy. Is it true, or does it merely propagate an innaccurate myth?"
I feel that these two instructions are contradictory. As soon as we start to thumb based on what we think of as "true", then we are also voting up comments that support our position. What are we to do with a contrarian who is unknowingly re-stating a previously debunked myth, or a Wattsupian refugee floundering in confusion, but who is civil and respectful and genuinely here to learn? I think they should earn a thumb.
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Tom Curtis at 16:38 PM on 8 October 2013Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
Here is a graph based on my suggestions @122:
As you can see, HadCRUT4 does not drop below model minimum trends, alghough the ensemble 2.5th percentile certainly does. Nor does HadCRUT4 drop below the 2.5th percentile line recently (although it dropped to it in 1976).
Skeptics may complain that the trends are obviously dropped down with respect to the data. That is because the HadCRUT4 trendline is the actual trend line. Trendlines run through the center of the data, they do not start at the initial point.
I will be interested to hear SAM's comments as to why this graph is wrong or misleading, and why we must start the trends on a weighted 5 year average so as to ensure that HadCRUT4 drops below the lower trend line.
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Harri H at 16:21 PM on 8 October 2013SkS social experiment: using comment ratings to help moderation
It might be interesting to note that the leading Finnish newspaper Helsingin Sanomat (www.hs.fi) uses a two-dimensional system with thumbs up/down in two categories: "I agree" and "Well argumented".
These seem highly correlated though...
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fredb at 15:57 PM on 8 October 2013SkS social experiment: using comment ratings to help moderation
It's not so much that this approach prodcuces uniformity, rather that in its simple implementation highly voted comments float to the top. Thus, in order to see other comments, such as highly down-voted comments, you have to scroll down and down ... most people wouldn't bother.
I encourage a look at the slashdot.org approach to crowd sourced moderation of comments comments, it works exceptionally well as a filter and yet allowing people to see the broader range of comments. -
Joshua at 15:49 PM on 8 October 2013SkS social experiment: using comment ratings to help moderation
It will be interesting to observe this system. Specifically, it will be interesting to see whether any "skeptical" comments recieve high ratings. I agree with Flakmeister - in that whenever I've seen such systems employed on blogs, they seem to have largely functioned to reinforce uniformity, or a predominant viewpoint. Even still, the system may help to reinforce a more constructive engagement within a limited range of opinions.
It would say a lot about this site if civil, well-written, and well-supported "skeptical" arguments got some high ratings. Of course, that would mean that there would have to be a substantial number of contributors who don't think that using those descriptors for "skeptical" aguments is oxymoronic.
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Flakmeister at 14:45 PM on 8 October 2013SkS social experiment: using comment ratings to help moderation
Well, I may be proven wrong but the up/down system doesn't do a job of moderation... Witness Zero Hedge where a high number of "greenies" only demonstrates the resonance within the echo chamber...
Call me skeptical....
Moderator Response:[PW] I'm fairly sure JC and the rest of the SkS team aren't intending the thumbing system to take the place of regularmoderators: quite the contrary--and speaking as a moderator--if/when I see multiple thumbs-down, *geenrally* it can be taken as a sign of a *possible*vtroll/contrarian, and, for me, just aids in my 'drive-bys,' daily, of the threads.
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John Mason at 14:42 PM on 8 October 2013A rough guide to the components of Earth's Climate System
OK I have edited the text accordingly. However, although the term 'strong' was in retrospect incorrect, 2010 did see moderate El Nino conditions for a time:
http://iri.columbia.edu/climate/ENSO/currentinfo/archive//201001/QuickLook.html
Tom - I'd call one of the five biggest El Ninos in a century pretty darned impressive!
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JasonB at 13:13 PM on 8 October 2013Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
Another way of illustrating the problem with SASM's graph:
Keep the minimum and maximum trend lines the same as they are now but instead of plotting HadCRUT, plot instead the individual model realisations (Tom's spaghetti graph @ 79).
Now the model realisations will be going outside of the "minimum" and "maximum" trend lines, and many of them will be "pushing the limits" — if fact, no doubt some of them go outside those "limits". How is it possible that the actual model realisations that are used to create those "limits" could go beyond them? Because those "limits" are not the limits of the monthly (or five-yearly moving average) temperature realisations, they are the range of the trends of those realisations. And they certainly do not start at that particular point in 1990 — each realisation will have its own particular temperature (and five-year moving average) at that point in time.
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Rob Honeycutt at 13:01 PM on 8 October 2013Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
SAM... Actually, I find your chart interesting in terms of illustrating why there is a problem centering on 1990.
Look at your chart for a moment. Do you notice how 1990 is at the peak of the 5 year trend? Try centering the start point forward or back a few years and see if you get a different picture.
Do you see how you can get a very different interpretation by just adjusting a few years? That indicates to me that that method doesn't provide a robust conclusion. Centering on 1990 certainly provides a conclusion that skeptics prefer, but it's not at all robust.
But again, as JasonB just restated, you're treating this as an initial condition problem when it's a boundary condition problem. You have to look at the full band of model runs, including both hindcast and projections, and compare that (properly centered) to GMST data.
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Paul Pukite at 12:46 PM on 8 October 2013A rough guide to the components of Earth's Climate System
My eyes lit up when I noticed how seriously you are treating the various realms of the Earth's climate system. I am starting up an earth sciences semantic web server and blog at http://ContextEarth.com. This is designed to encompass the various realms of the earth and its natural resources, using an organization provided by the SWEET ontology from JPL. It's all open sourced so I intend to open it up to those who have some interest in the topic.
An example of a recent post is on compensating the GISS temperature record with the SOI time series. This analysis was inspired by charts that Kevin C and Icarus posted on SkS recently.
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JasonB at 12:41 PM on 8 October 2013Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
SASM @ 117,
Basically, this is the same chart as Tom Curtis has drawn @88, except I continue to show the raw monthly HADCRUT4 temperature data and a 5-year center moving average.
No, it's not. Tom's chart draws trendlines only. As a consequence, there is no initial value problem and all trend lines can safely start at the same point.
You show actual temperature anomalies and compare them with trendlines. This has two problems:
1. You anchor the trendlines to start the on the 5-year centred moving average temperature in 1990. If you really want to go down this path and you want to do it "properly", then you should use a much longer average than 5 years. Given that climate is commonly defined to be the average of 30 years, you should use the 30-year centred moving average at 1990. By my calculation that would drop the starting point by 0.04 C, making a big difference to the appearance of your chart.
2. More importantly, comparing monthly data with straight trendlines will naturally show periods where the monthly data (and even smoothed data) goes outside those trendlines, even when those trandlines are minimum and maximum trend lines. That's because they're the minimum and maximum range for the trend, not the minimum and maximum values for the monthly figures at any point in time! Plot the trend line for HadCRUT starting at the same point and ending today. Does it lie well within the minimum and maximum trend lines? Obviously it must, this is what Tom showed. Include the range of uncertainty for the trend itself. What is the likelihood that the true trend does not lie within the minimum and maximum range forecast? As a bonus, if you include the range of uncertainty for the trend itself then you can generate shorter and shorter trends for comparison, and if you do, you'll find that the forecast trends continue to overlap the range of trend values despite the actual trend value swinging wildly because the range will naturally grow wider as the time period becomes shorter.
The bottom line that you have to ask yourself when generating these charts is "How is it possible that I can reach a different conclusion by looking at my chart to what I would infer from looking at Tom's or Tamino's chart (second figure in the OP)?" If the answer is not immediately obvious to you then you need to keep working on what the charts mean.
Dana goes to great length to attempt to explain that the left draft chart was a mistake due to baselining issues. My chart of the raw temperature data and Tom’s min/max model looks very similar to the draft IPCC chart. I doubt the people developing the draft chart made a major baseline mistake as claimed by Dana.
You shouldn't need to "doubt", it's obvious that they made a mistake. It makes no sense to anchor your projections on the temperature record for a particular year. The fact that you think Tom's chart "looks very similar to the draft IPCC chart" means you haven't understood the fact that by comparing trends alone Tom has completely sidestepped the issue.
If you really think you're onto something, then to prove it you should be able to do so using either Tom's chart or Tamino's. If you cannot, and you cannot say why Tom's chart or Tamino's chart do not support your claims, then you need to think a little bit more.
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Tom Curtis at 12:40 PM on 8 October 2013A rough guide to the components of Earth's Climate System
One Planet Forever, I like graphs because they convey quantities (approximately) very quickly. In that context, the 97/98 El Nino was not a super El Nino. It was only the fifth largest on record. It had the misfortune of not coinciding with a major volcanic eruption (unlike the largest), and of occuring in a time of elevated global temperatures (unlike the other four stronger El Ninos). 2010 was so weak an El Nino that it almost qualified as a La Nina.
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One Planet Only Forever at 12:28 PM on 8 October 2013A rough guide to the components of Earth's Climate System
John Mason,
I am not a fan of unquantifiable terms like "Super vs. Strong" to indicate a difference. As an engineer I tend to prefer the more precise presentation of differences. The clarification of El Nino strengths could be made by saying the 1997/98 event was significantly stronger than the 2009/10 event and referring the reader to the NOAA ENSO History. Even saying one was significantly stronger really doesn't "quantify the difference". And I think a reference directly to the NOAA ENSO history helps a person figure it out for themselves. It may also lead a person to explore more of the information that is avaialble. They might decide to open a few of the other links at NOAA.
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Tom Curtis at 12:20 PM on 8 October 2013Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
SAM, there are several problems with your graph as is.
The largest problem is that you do not show the observed trend. If you are showing the natural variation of the data, you should also show the variation in the models for a fair comparison, ie, something like the inset of my graph @79. Alternatively, if you want to compare trends, compare trends!
If you also want to show the actual data, that is fine. The way I would do it would be to show the actual 1990-2013 trend for the data, properly baselined (ie, baselined over the 1990-2013 interval. I would then show the range and mean (or median) of the model trends baselined to have a common origin with the observed trend in 1990.
Doing this would ofset the origins of the trend comparison from the temperature series. That has the advantage of making it clear that you are comparing trend lines; and that the model trend lines shown are not the expected range of observed temperatures. Ie, it would get rid of most of the misleading features of the graph.
You may also want to plot the 2.5th to 97.5th percentiles (or min to max) of the model realizations set with a common 20-30 year baseline (either 1961-1990, or 1981-2000) to allow comparison with the expected variation of the data on the same graph. That may make the graph a little cluttered, but would allow comparison with both relevant features of the model/observation comparison.
As is, you do not compare both. Rather you compare one relevant feature of observations with the other relevant feature of models; and as a result allow neither relevant feature to actually be compared.
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Leto at 12:15 PM on 8 October 2013Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
Tom @ 118,
The 2.5th and 97.5th centiles would be of interest, given the traditional (but arbitrary) interest in the central 95% of a spread of values.
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