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Comments 82501 to 82550:

82501. RSVP at 06:24 AM on 16 June 2011
       The greenhouse effect is real: here's why
       Daniel Bailey 31 Why exactly a concern for global warming when the change of global CO2 ppm is already bad enough? In other words, if 394 ppm is a detriment on its own right, what does correlating this to climate change bring to table?
82502. Daniel Bailey at 06:22 AM on 16 June 2011
       Phil Jones - Warming Since 1995 is now Statistically Significant
       @ Dikran I think we're in close agreement here. No matter the answer Jones gave, it was going to be spun out of context. My point I was trying to make (poorly) was that in not addressing the framing of the question immediately, anything that followed would be playing into the hands of the denialarati. That was the fallacy (perhaps there's a better word?). Thus, following a normal scientific response to a question given, the outcome had a predictable end. (It was essentially one of those "So, how long has it been since you stopped beating your wife?" questions)
82503. michael sweet at 05:37 AM on 16 June 2011
       Speaking science to climate policy
       The aerosols are Hansen's Faustian Bargian. Hansen estimates the forcing as -1.3 W/m2. According to Bart's 0.8 C/W/m2 @3, that is over 1C of committed warming in addition to what is in the pipeline due to ocean thermal inertia. As dmccubbi says, they have a residence time of only a few days or weeks. They are continually renewed (they are one of the major components of the asian brown cloud and acid rain in the US Northeast). When they are cleaned up (eventually they must be cleaned up) the climate forcing will immediately increase. The bargain is that the aerosol pollution today will keep temperatures from rising untill the aerosols are no longer released. This committed warming is hidden for the present.
82504. Albatross at 05:37 AM on 16 June 2011
       It's the sun
       Sigh, Let Tamino know...probably another crank paper that needs to be refuted.
82505. Bob Lacatena at 05:32 AM on 16 June 2011
       It's the sun
       826, Tor B, Until his work is published in its entirety, and available to all, it is only so much blather, and very unlikely to undergo scrutiny, since no one else to date has been able to accomplish what he claims, and quite to the contrary, a number of existing studies demonstrate the opposite. [See the #2 denial argument, It's the Sun.] At this point, all you can do is to claim that he claims that he's submitted the masterful diagnosis which overturns all of modern climate science. Forgive me if I don't sit up too straight in my chair. At the same time, he will also need to explain other things, like why CO₂ is not causing any warming (considering that the mechanism is very well understood, and it would be a huge surprise if that mechanism is totally and completely misunderstood by all atmospheric physicists around the globe). Sorry, but your post is only so much "trust me, I know a guy who knows the truth, just wait" hand waving, and as such is a wholly inappropriate claim to make.
82506. Rob Honeycutt at 05:19 AM on 16 June 2011
       Phil Jones - Warming Since 1995 is now Statistically Significant
       JMurphy... You're right. They absolutely would have spun the whole thing the way they wanted regardless of what Jones said. But, by opening his answer with the word "yes" he basically loaded their weapons for them.
82507. Dikran Marsupial at 05:08 AM on 16 June 2011
       Phil Jones - Warming Since 1995 is now Statistically Significant
       Daniel, the question isn't a fallacy, it is actually a perfectly reasonable question, it is the implicit conclusion that global warming is not happening that is a fallacy, but that was unsaid and was made afterwards by the "skeptic" media.
82508. Riccardo at 05:00 AM on 16 June 2011
       It's the sun
       Thanks DB. Actually there's not much there either, only a figure more. Assuming that it can not simply be "solar forcing integration", we need to know more about his model before commenting. And sure I'd not be thrilled by a "mathurbation".
82509. shoyemore at 04:49 AM on 16 June 2011
       The Planetary Greenhouse Engine Revisited
       This is good. Best explanation I have seen of pressure broadening, whic is important to explain why band saturation is not occurring for CO2 absorption wavelengths.
82510. Utahn at 04:48 AM on 16 June 2011
       There's no room for a climate of denial
       Probably too late for this thread but thought I'd post anyways: Norman: "How many consensus views in the Medical field have been overturned? Consensus views of 'experts' in their field have been overturned and wrong." I'm in that field, and I think it's actually not that often that true consensus views get overturned. A bigger problem is that a few hypothesis-generating retrospective papers come out suggesting some effect of a medication or intervention and the media overhype the results. Then later more scientifically valid prospective papers overturn what was never really a "scientific" consensus (estrogen for heart attack prevention is an example that comes to mind). Anyways, back on topic, I think we don't often discuss in the context of the psychology of denial, the prerequisite that that which is being denied must be so disturbing as to threaten a core belief or understanding. In the medical field you may often come across a patient who denies that they have hypertension because it is a threat to their core perception that they are "healthy" or "not the kind of person who needs medication". In cancer patients, denial of a potentially fatal cancer may occur due to the threat to our belief we are "healthy", but also because of the threat to our belief that we will not die. Often these forms of denial come in the form of minimizing the threat, as the evidence of a problem may be too obvious to deny. I think because we don't like to talk about politics, we often don't discuss the core beliefs threatened by climate change. In my opinion and in that of many others, this threatened core belief usually centers around a strong faith in the free market. But other threatened beliefs I think can also be involved "I'm not a polluter" being one. I hope these underlying threatened core beliefs that lead to denial are addressed in John's book that I plan to read, because I know that without addressing these in the medical field, denial is pretty hard to beat...
82511. dmccubbi at 04:46 AM on 16 June 2011
       Speaking science to climate policy
       The residence time for aerosols depends, I think, on where the aerosols are located. Sulfates from volcanic eruptions can end up in the stratosphere, and stay there for a few months or years. Aersols from non-volcanic sources (dust, sulfates, nitrates, organic aerosols, black carbon, etc) stay in the lower atmosphere on the order of days.
82512. JMurphy at 04:26 AM on 16 June 2011
       Phil Jones - Warming Since 1995 is now Statistically Significant
       I think Phil Jones gave an answer which was correct, easily understandable and honest. The fact that those in denial used a version of his answer to try to claim things that Phil Jones did not mean or say ("Global Warming in Last 15 Years Insignificant, U.K.'s Top Climate Scientist Admits" from FOX NEWS, and "Climategate U-turn as scientist at centre of row admits: There has been no global warming since 1995" from the DAILY MAIL - both headlines are demonstrably false), simply shows how despicable and dishonest they are. No matter how Jones had answered, his words would still have been twisted and abused. Don't have a go at Jones for being naive, credulous or whatever - his answer would never have been perfect enough to have disallowed its use as propaganda by those who thrive on disinformation. Have a go at those who misuse and misinform.
82513. Riccardo at 04:11 AM on 16 June 2011
       It's the sun
       I don't know what's going around the intertubes, I couldn't find the paper. Maybe people is talking about nothing. We'll see.
       Response:

       [DB] Try Stockwell's blog here.

82514. Rob Honeycutt at 04:05 AM on 16 June 2011
       Phil Jones - Warming Since 1995 is now Statistically Significant
       To back up Daniel here... This is all just the nature of language and communication. How we structure our language is part of everyday life for all of us. Politicians use techniques to dodge questions in order to not answer them. I think what Daniel, Dana and I are suggesting is it's important to dodge the "trap" when a question is structured in a way that's intended for such a purpose. But also, follow that with a full and complete answer to the question. Phil Jones could clearly have answered the question in full without falling for the trap. I think Dr. Jones' Achilles heel is that he so much of a scientist that he answered the question in a manner, as Dana suggested, that addressed a scientific audience. Any scientist listening to his words knew exactly what he meant. The general public did not. And that was the trap.
82515. KR at 03:54 AM on 16 June 2011
       Forecast: Permanently Hotter Summers in 20-60 years
       Karamanski - Lower temperature ranges in the tropics (warm all year around) mean that any increase in average temperature will exceed the ranges faster than will happen at the poles. Arctic summer temperatures are somewhere around −10 to +10°C (20°C range). Fiji, on the other hand, has a temperature range of about 27 to 31°C (4°C range). So a 2°C rise in temperature in Fiji will make averages exceed current maxes, while it would take at least ~5°C for that to happen in the Arctic. The tropics don't heat as fast as the poles, but they don't have to for average temperatures to exceed all extremes. And tropical biota are much less adapted to temperature changes - this is going to be a serious stress on the tropical biosphere.
82516. Tor B at 03:50 AM on 16 June 2011
       It's the sun
       I read the following from comment #997 in Jeff Master’s blog today. I expect that someone with knowledge will have to pick his writing apart, as an article is making the rounds on the intertubes, apparantly based on Stockwell's writing. What follows is comment #997: Another blow to the AGW theory... Dr. David Stockwell who has a PhD in Environmental Sciences submitted a recent paper, that shows that solar activity alone, could explain Global Warming. I believe that GCC has more of an impact than the sun, but it's interesting nonetheless. Quote: Finally, my hibernation of the last 6 months is coming to an end, with the formal submission to a journal yesterday of the fruits of my labor. The main points: 1. solar forcing is time-integrated and not direct, 2. accumulation of the 0.1W/m2 increase in solar irradiance in the 20th century explains global warming, 3. there is a credible explanation for global warming that does not involve increases in human emissions of greenhouse gasses. Figure: Cumulative solar irradiance (blue) and volcanic forcing (red) is highly correlated with HadCRU global temperature and explains the trend in temperature since 1950. The direct solar irradiance (orange) is uncorrelated with temperature. There are a lot of other points about the model that no doubt I will get into in time. For the moment, here is the Conclusion. Contrary to the consensus view, the historic temperature record displays high sensitivity to solar variations when related by slow equilibration dynamics. A range of results suggest that incorrect specification of the relationship between forcings and temperature may be at the heart of previous studies finding low correlations of solar variation to temperature. The accumulation model is a credible alternative mechanism for explaining both paleoclimatic temperature variability and present-day warming without recourse to increases in heat-trapping gases produced by human activities. The grounds on which a solar explanation for late 20th century warming is dismissed should be reconsidered.
82517. Daniel Bailey at 03:50 AM on 16 June 2011
       Phil Jones - Warming Since 1995 is now Statistically Significant
       @ Dikran: I'm not advocating to speak as a politician, but to first establish control of the narrative, then expose the question for the fallacy it is and to then give the actual answer with appropriate context to make it a teaching moment. But the initial sentence used is key, as it sets the stage for establishing control of the narrative to be played out. That initial response by Jones is the area of opportunity to seize control of a bad situation and to establish a more appropriate response. A good defense is to establish a counteroffensive which also dictates the terms of the engagement. Answering the question without reframing it is to engage at a disadvantage: the battle may ultimately be won but the campaign itself is lost.
82518. Dikran Marsupial at 03:30 AM on 16 June 2011
       Phil Jones - Warming Since 1995 is now Statistically Significant
       Philippe Chantreau IMHO that is exactly why few people would trust a politician further than they could throw them, the last thing scientists should do is follow in their footsteps!
82519. Philippe Chantreau at 03:27 AM on 16 June 2011
       Phil Jones - Warming Since 1995 is now Statistically Significant
       Right Daniel, that's exactly what politicians do. Politicians have been exposed over the years to lots of actually good journalism, faced with questions to which they did not have a good answer, or no answer at all. They learned these methods to cope with it and come out at the end saying many words that add up to no meaning. It is rather ironic that now these methods should be used by honest people having to answer dishonest questions, but perhaps scientists should start familiarizing themselves with it, less their words be bent in endless twists of deception.
82520. Tom Curtis at 03:22 AM on 16 June 2011
       Forecast: Permanently Hotter Summers in 20-60 years
       Karaminski @43, see my final paragraph in 6 above.
82521. Albatross at 03:05 AM on 16 June 2011
       Forecast: Permanently Hotter Summers in 20-60 years
       For those discussing the expected impact of a solar min on global temperature, please continue the discussion here ("What would happen if the sun fell to Maunder Minimum levels?").
82522. Karamanski at 02:57 AM on 16 June 2011
       Forecast: Permanently Hotter Summers in 20-60 years
       "According to both the climate model analysis and the historical weather data, the tropics are heating up the fastest. "We find that the most immediate increase in extreme seasonal heat occurs in the tropics..." The finding that the tropics are warming up the fastest seems to run counter to the fact that the polar regions are warming up faster than any region on the planet. It doesn't make much sense why the tropics would heat up faster than the mid-lattitudes. Does anyone have an explanation for this?
82523. Eric the Red at 02:56 AM on 16 June 2011
       Forecast: Permanently Hotter Summers in 20-60 years
       Exactly Sky, If we experience a deep solar minimum, then the influence of solar activity can be put to rest. Since solar activity increased for much of the last century, its influences has not been satisfactorily dismissed. I am not sure why you are so quick to dispute decadal oscillations though. Especially since paragraph one indicates that solar influences are minimal, but paragraph two says that a deep solar minimum is significant. Yes, the background continues to rise. But the rise is very bumpy, and if we can identify the bumps (at least the larger ones), then we can more accurate make forecasts.
82524. Daniel Bailey at 02:13 AM on 16 June 2011
       Phil Jones - Warming Since 1995 is now Statistically Significant
       FWIW, I would have answered something like this: "That's an interesting question, and let me tell you why it's an interesting question..." First align with the questioner, then differentiate to reveal the fallacy of the question.
82525. les at 02:11 AM on 16 June 2011
       Phil Jones - Warming Since 1995 is now Statistically Significant
       121 - Rob Honeycutt Thanks. I really was at a loss to see what MoreCarbonOK was trying to say. You seem to have been able to read his posts better than me.
82526. dana1981 at 02:07 AM on 16 June 2011
       Phil Jones - Warming Since 1995 is now Statistically Significant
       Exactly Rob - the question was fed to Jones in a way to get him to answer "yes". As soon as he did, the "skeptics" got all they needed, as we saw from Fox News, Daily Mail, etc. I sympathize with Jones, because when I'm asked a yes or no question, I tend to answer yes or no and then clarify with the "but" if necessary. So like I said, my initial reaction would have been to respond the same way as Jones did. But when the question is being asked to trap you into a specific answer, you have to think outside the box and find a different way to answer it. And it's tricky, because scientists aren't normally asked loaded questions like that. Hence the need for media training.
82527. skywatcher at 02:06 AM on 16 June 2011
       Forecast: Permanently Hotter Summers in 20-60 years
       Deep solar minimuam and continued temperature rise = solar activity is less important in climate issues. Nobody in their right mind would eliminate it entirely from the list of climate forcings. That would be foolish and naive, and is not what climate science is all about. Dreams of oscillations in the climate of the past 100 years, created using an eyecrometer on the wiggles in the rising temperature curve inevitably have a bad ending - they are, as Tamino observes, mathturbation. Each wiggle has it's own cause - aerosols in the 1960s, deep solar minima now and early in the 20th century for example, and the sume effect on the temperature curve is to make some think of an oscillation that isn't really there. Seeing as the background continues to rise steadily, summers and winters will be much hotter soon enough, and no fantasy oscillation will help the cause.
82528. Rob Honeycutt at 01:56 AM on 16 June 2011
       Phil Jones - Warming Since 1995 is now Statistically Significant
       Dana... You're totally right. I imagine Jones was torn between being accurate and feeling trapped by the question. I think he should have lead with a comment suggesting it's a misleading question. From the moment Jones said, "Yes. But only just." People only heard the word "Yes." Everything after that was just trying to climb out of the pit he'd fallen into. Better to point at the pit first, side step it, explain why it's a pit and then answer the question as accurately as possible. Hindsight 20/20. I can't find the link at the moment but the recent John Abraham radio interview was a very good example of side stepping the traps and accurately explaining the science.
82529. Rob Honeycutt at 01:44 AM on 16 June 2011
       Phil Jones - Warming Since 1995 is now Statistically Significant
       moreCarbonOK.... Reading through your comments here and looking through your site I believe I see most of your sources of information seem to be restricted to JoNova, WUWT, Monte Heib and others. With all due respect, you seem to be actively searching for sources that confirm what you want to believe. You've pieced together, for yourself, the same narrative being propagated by a very active anti-science crowd of people. The material you're putting together may feel right to you, it may be what you want to believe, it may sound very compelling to you. It's not science. It's not accurate. If you were truly skeptical you would take the time to try to learn what the actual scientific research says. The reason I've come to trust this particular blog (SkS) over many others is that it provides citations to actual research. Research that I go read for myself. In that I don't have to trust John Cook or any of the other authors here. I can be skeptical of even their claims. But they give me the opportunity to go to the source of the information and see for myself if their claims are accurate. I would urge you to try to do the same with JoNova, WUWT and others. I think you'll find that they mostly stick to referencing each other, not the published research. I suggest being skeptical of your own position. I try to do the same with my position every day.
82530. dana1981 at 01:35 AM on 16 June 2011
       Phil Jones - Warming Since 1995 is now Statistically Significant
       I just think you have to keep the audience in mind. In a BBC interview, the audience is the general public. With that audience, you don't want to give a technical answer which is heavy on statistics and requires diagrams and several pages of text. Jones' answer was good if his audience was full of scientists and statisticians. I understand why Jones answered the way he did, and without giving it a lot of consideration before answering, I probably would have said "yes, but..." just like he did. But that's a mistake. I think you have to answer that question by explaining what's wrong with the question. You can't play into their trap by feeding them the answer they want. I think Jones should have used it as a teaching moment. "Well, here's why we look at temperature changes over periods of 20-30 years, and why 15 years is too short..." Then you can explain that it's not surprising why the 15 year trend is statistically insignificant, because you've already established that it's simply too short of a timeframe. As has been suggested, knowing how to properly answer this question probably requires some media training - learning how to communicate with the general public, who don't know what "statistically significant" means.
82531. KR at 01:27 AM on 16 June 2011
       Examining Dr. John Christy's Global Warming Skepticism
       jonicol - In regards to the CO2 specifics you raised in your post @52, I would suggest reading (and querying/commenting upon) the There's no tropospheric hot spot thread.
82532. dana1981 at 01:25 AM on 16 June 2011
       Speaking science to climate policy
       I like this article, except for the comment that we're committed to another third of a degree warming. It's twice that, and as bart notes, even more once atmospheric aerosols are reduced. But the comments about risk thresholds and needing to cut emissions immediately are spot on. Bern - aerosols have a very short atmospheric residence time, just a couple of years I believe. As we reduce aerosol emissions, atmospheric concentrations will drop rapidly. If you just consider GHGs and ignore the aerosol forcing, that gives the upper bound for committed warming. That's bart's 2.4°C from current GHG levels, although technically it's not an upper bound because he's using the most likely climate sensitivity value (3°C), not the upper bound (4.5°C or more).
82533. Daniel Bailey at 01:22 AM on 16 June 2011
       The greenhouse effect is real: here's why
       Speaking of CO2, the May Mauna Loa data is out: 394.16 [Source] No "bend" visible in the trend yet, so let's all hope that June won't continue the upward arc...
82534. Albatross at 01:19 AM on 16 June 2011
       Forecast: Permanently Hotter Summers in 20-60 years
       To get back on topic, Tamino has a very interesting discussion on the Diffenbaugh research, and explains why the departures from hitherto natural variability is expected to occur in the tropics first. Recommended reading for all interested in this post. Note: And Eric, IIRC no-one here, and certainly not the science cited in the IPCC reports is dismissing "every other climate forcing". You are tearing down a strawman that you have created...well done, and please reply to this on an appropriate thread.
82535. KR at 01:16 AM on 16 June 2011
       Phil Jones - Warming Since 1995 is now Statistically Significant
       Dikran - "I don't mean to be argumentative, it is just that Jones did a very good job of dealing with this very difficult question. I don't think I could have done any better without the use of diagrams and a page or two of text." I agree. I find it extremely difficult to talk without a whiteboard sometimes.
82536. Bob Lacatena at 01:10 AM on 16 June 2011
       The greenhouse effect is real: here's why
       29, Tom Curtis, Yes. I agree with all of your points... but still, to me, the issue comes back to one of precise quantification. The logic is there, but (as we've seen is already the case with the simple task of measuring and computing what are obviously rising global temperatures) getting through the noise to an indisputable argument is tricky.
82537. Dikran Marsupial at 01:04 AM on 16 June 2011
       Phil Jones - Warming Since 1995 is now Statistically Significant
       KR yes, that interpretation is fine, but it still admits that it is not significant (so they would probably make the same claim anyway - logical consistency had nothing to do with it!). The real problem is then when a skeptic has a non-significant statistic, are they allowed to say that the statistic is suggestive of support for their theory? The reason we are not supposed to claim anything based on a statistically insignificant statistics is to guard against confirmation bias. Essentially we should always apply the intepretation that provides the weakest support for our own position. Jones did just that, the Daily Mail did the exact opposite and used the (incorrect) interpretation that provided the most support for their position. However in reality hypothesis tests generally provide little support for any position (and so a pessimistic intepretation is a good idea). I don't mean to be argumentative, it is just that Jones did a very good job of dealing with this very difficult question. I don't think I could have done any better without the use of diagrams and a page or two of text.
82538. macoles at 00:56 AM on 16 June 2011
       Phil Jones - Warming Since 1995 is now Statistically Significant
       MoreCarbonOK Pardon my earlier assumption that your wild variation of month based trends was due to your treatment. I was able to replicate a very similar trend of -0.108 C/yr for the Brisbane AP May Minima series. Although it is also apparent that the detrended standard deviation is 1.18 C (or 33% of the total trend change over the period). However the fact remains that, just as no-one would base average global temperatures on just 10 sites to show a statistically significant warming trend, no-one would seriously base a SH cooling trend on just 5 sites. You need far more site dirversity before you can make the point that you do.
82539. John Russell at 00:55 AM on 16 June 2011
       Phil Jones - Warming Since 1995 is now Statistically Significant
       Dikran writes: "Media training is vital for any scientist that need to have contact with the press, but nothing can provide a 100% bulletproof defense." Well then, I think we agree; because I was never saying there is a bullet proof way to respond. Rather I was saying that, in his innocence, Phil Jones made it much too easy and there would have been ways of expressing an honest answer that would have been more difficult to twist -- or even if twisted, easier to demonstrate as obfuscation. I'm sorry I can't come up with one, but that's because I'm not an expert on the science. Cheers!
82540. Tom Curtis at 00:49 AM on 16 June 2011
       The greenhouse effect is real: here's why
       Sphaerica @28 considering just the radiation, a reduction in aerosols will result in a cooling stratosphere and warming troposphere. That may (or may not) be countered (or reinforced) by chemical interactions between sulfates and ozone. I will point out three things with regard to your point @20: First, the H2O feedback effects which cause even solar warming to partially mimic the CO2 feedback are acting against the natural signatures of solar forcings, but reinforcing the natural signature of the greenhouse effect. Therefore the signature will be stronger for a greenhouse forcing than for a solar forcing. Second, the feedback effects will only significantly mimic the greenhouse signature overall if the H2O feedback is a strong feedback. If it is weak it will not swamp the opposite sign signatures from a solar forcing so that solar forcings mimic greenhouse forcings in both sign and (approximately) magnitude. Third, the H2O feedback will not mimic the stratospheric cooling because the H2O is not carried to the stratosphere because of the very low temperatures at the tropopause. The effect of these three points is that any honest analysis of the greenhouse signatures will place an honest skeptic in the position where they must either accept a GHG driven global warming because of the signatures, or accept it because they are committed to a strong feedback along with the cooling stratosphere.
82541. Albatross at 00:46 AM on 16 June 2011
       Phil Jones - Warming Since 1995 is now Statistically Significant
       JMurphy @108, The Moniker was a clear give away. IMHO, his posts belong on the "denial" thread more than they do here. And the irony, a post about cherry picking and the guilty party who thinks that doubling or trebling CO2 is OK goes right ahead an cherry picks to continue to reinforce their opinion on the matter. Meanwhile for the period which we almost have (almost complete global coverage) sufficient data to determine statistically significant temperature trends we get this: [Source] The planet is in a net energy imbalance and is warming....deal with it folks.
82542. KR at 00:42 AM on 16 June 2011
       Phil Jones - Warming Since 1995 is now Statistically Significant
       Dikran - So, incorrect terminology and implications (thanks, I don't have multiple publications in statistics): Would this be more correct? "Statistical significance at the 95% level means that there is a 1 in 20 chance of seeing a trend as large or larger assuming the null hypotheis is true, while statistical significance at the 93% level means that there is a 1 in 14 chance of seeing a trend as large or larger assuming the null hypotheis is true. So again, while 93% significance over that period is suggestive, the short time frame data does not meet the statistical significance threshold, which is why 20-30 years of data is preferred to clearly identify trends." The major point aimed for here is to emphasize that while the data is pointing in a particular direction, it's not doing so strongly enough to meet the standard test - hopefully not leaving room for the interviewer (or onlookers) to say "No warming since 1995"...
82543. Eric the Red at 00:38 AM on 16 June 2011
       Forecast: Permanently Hotter Summers in 20-60 years
       If you are unwilling to listen to his presentation, then fine. That is your loss. Also, if you are so willing to dismiss every other climate forcing and cling to the "its only CO2" argument that influences the climate, then why do you even bother posting? Since his presentation is a direct challenge to the above statement that "simulations have accurately predicted the Earth climate during the past 50 years," which is so blatantly false, I would consider it quite relevant. Not to mention the questionable statement that, "the tropical regions may see the most dramatic changes first." In the U.S., summers may be hotter than the most recent 50, but will they be hotter than the hottest summers of 75 years ago?
       Response:

       [DB] Please see http://www.skepticalscience.com/1934-hottest-year-on-record.htm.  Also, please try to keep the tone more civil.  As others have pointed out, Latif himself is on record as saying he was misrepresented.  But that entire episode is off-topic here.  If you wish to pursue it, then do so at the link Sphaerica provided.

82544. Dikran Marsupial at 00:38 AM on 16 June 2011
       Phil Jones - Warming Since 1995 is now Statistically Significant
       Tom Curtis wrote "Where I do part ways with you, and agree with John Russell is that because it is always possible to answer better, I think media training would be useful for climate scientists who are often called upon to front the media. " Actually, I don't disagree with that at all, in fact I said media training is vital for any scientist that needs to communicate with the media. It is the particular question that is the problem, I doubt there is an accessible answer that can't be substantially misconstrued. I think Jones' answer was better than any of the alternatives presented so far. The was a logical disconnect between the "the trend is not statistically significant" and "there has been no warming". If your opponent is not required to be logically correct, there is little you can do, especially with a topic as counter-intutive as hypothesis testing. There are plenty of working scientists who don't understand it properly.
82545. Dikran Marsupial at 00:31 AM on 16 June 2011
       Phil Jones - Warming Since 1995 is now Statistically Significant
       KR sadly that interpretation isn't correct. Statistical significance at the 95% level means that there is a 1 in 20 chance of seeing a trend as large or larger assuming the null hypotheis is true. That does not mean that there is a 1 in 20 chance that the null hypothesis actually is true. This is mixing frameworks, but the p-value is p(x>X|H0), where x is the trend and X is the observed trend and H0 is the event that the null hypothesis being correct, however what you actually want is p(H0|x>X), which you can get by Bayes formula p(H0|x>X) = p(x>X|H0)p(H0)/(p(x>X|H0)p(H0) + p(x>X|H1)p(H1)) however the hypothesis test does not involve p(H0), p(H1) (the prior probability that the null and alternative hypotheses are correct) and p(x>X|H1), which measures how likely such an extreme statistic is assuming that there is a secular trend. Essentially a frequentist hypothesis test does not allow you to assign a numeric probability to either hypothesis being correct as it can only assign probabilities to things that have long run frequencies and the a particular hypothesis is either true or ot isn't. However, that is exactly the form of answer we actually want, which is why the p-value is so often misinterpreted that way. That makes it very difficult to give an accessible answer to the question that is also correct as statistical significance simply doesn't mean what people think it means. JMurphy Absolutely, I gave him the benefit of the doubt, but he showed he was a denialist by being unwilling to engage with the substantive technical criticism of his methodology. The hubris was priceless, though ;o)
82546. Tom Curtis at 00:30 AM on 16 June 2011
       Phil Jones - Warming Since 1995 is now Statistically Significant
       Dikran Marsupial @77, certainly the deniers could have misrepresented Jones as you indicate if he had replied as I suggest. The issue is not whether what he said can be misrepresented, as everything can. The issue is how clear is it that it is a misrepresentation for those seeing the initial quote. In the instance where deniers had tried your suggested response, they leave themselves open to the obvious counter response that of course it is inappropriate to base claims on data that is not statistically significant; that that is why Jones bases his claims on thirty year trends which most certainly are warming, and are statistically significant; but that he was asked about a particular period which was only being discussed because deniers cherry picked a short interval to misrepresent the actual trend. The issue has then become the thirty year trend, and denier cherry picking rather than obscure arguments about which definition of "significance" is being used. Having said that, while I do believe that Jones could have answered better, I am in no way inclined to condemn him for that. As can be seen by this discussion, it is by no means easy to formulate an answer that is difficult to misrepresent, and far more so when doing so on the fly. And as I previously noted, and contrary to John Russell, even pausing to think can be misrepresented by hostile editing, so answering on the fly is more or less necessary. Where I do part ways with you, and agree with John Russell is that because it is always possible to answer better, I think media training would be useful for climate scientists who are often called upon to front the media.
82547. Bob Lacatena at 00:25 AM on 16 June 2011
       The greenhouse effect is real: here's why
       27, Chris G, Yes, but with error bars. That is, I suspect someone out there may have the knowledge to quantify this properly... it's just that I don't, and can't find it. At the same time, I do think that putting together all of the expected differences, no matter how vague individually (poles, winters, radiation measurements, stratospheric cooling, etc.) might produce a final answer with very small error bars. Really, I think there's a whole scientific paper in there that needs to be written, to consolidate and properly quantify the evidence. Except I think that's only of interest to combating denial, and not really of interest to the scientists who don't feel the need to prove that... they've got better things to work on. [This came up in past months, on another thread, and there's a graph there in the post or in the comments that shows an increased diurnal effect coincident with expected AGW, so maybe the fuzziness isn't as great as imagined. But I can't seem to find it.] Again, I think it all comes down to proper quantification, rather than eyeballed, rule-of-thumb logical inference. [Last note... stratospheric cooling is, to me, sort of a show stopper. Nothing else causes stratospheric cooling, as far as I know, so right there, there's no real need for everything else, except that a wealth of evidence is always preferable in any case.]
82548. Tom Curtis at 00:18 AM on 16 June 2011
       Phil Jones - Warming Since 1995 is now Statistically Significant
       Sorry, misplaced my second paragraph in 107 while editing. It should be placed at the end of the above comment (where it makes more sense).
82549. KR at 00:16 AM on 16 June 2011
       Phil Jones - Warming Since 1995 is now Statistically Significant
       I think I would have said something along the lines of: "The 'statistical significance' test is 95% confidence, which is to say one chance in 20 that your data shows the trend incorrectly, that it's instead your null hypothesis plus noise. For that 15 year period the confidence is ~93%, or about one chance in 14 that the data doesn't correctly reflect the trend, so while it's suggestive, that short time frame doesn't meet the generally used significance criteria."
82550. JMurphy at 00:15 AM on 16 June 2011
       Phil Jones - Warming Since 1995 is now Statistically Significant
       Dikran and others, I fear you are wasting your time with MoreCarbonOK - you only have to look at his website, to see classics like this : A short summary of the basic results of my study: CO2 is insignificant as a greenhouse gas. CO2 is not a poison or a pollutant. CO2 is one of the two main building blocks of ALL plant life on Earth. CO2 concentration has been up to ten times higher in the past CO2 is good. To start off with, I found Svante Arrhenius' formula completely wrong... It appears that we have not even yet reached the level of warmth compared to previous warm periods in known history, such as for example, the Medeviel Warm Period (MWP) - 1000 years ago, when Greenland was really green. See here: (Link to WUWT removed) Now the opposite, global cooling, that really is something to worry about.... There are some people there who make admirable attempts at showing him where he is going wrong, but there are none so deep in denial as those who believe that they have the secret answer and who believe they are more intelligent than the rest of us mere mortals !

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