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Comments 54301 to 54350:

  1. A vivid demonstration of knee-jerk science rejection
    Sphaerica, the question "Do you think human activity is a significant contributing factor in changing mean global temperatures?" elicits 97.5% "yes" response from climate scientists (See /global-warming-scientific-consensus-intermediate.htm) I believe a majority of skeptics would also answer yes. But there are lot who say no, especially when the word "significant" is used in the question. My question for you is what is the quantitative consensus of climate scientists on sensitivity? IOW, what range of S would 90% or 95% or 97% agree on?
  2. A detailed look at climate sensitivity
    Michael, I had to work today and appreciate your patience. Here's an JGR article for which I only have an abstract: Estimating the global radiative impact of the sea ice–albedo feedback in the Arctic which puts the albedo affect of sea ice loss at approx. 0.1W/m2. From the bottom of this page http://www.esrl.noaa.gov/gmd/aggi/ we can see that's the same forcing as about 3 years worth of manmade GHG. That's only ice, they don't have numbers for loss of permanent snow. The total realistic forcing from ice loss from the abstract above is 0.3W/m2. The total forcing from albedo from ice loss during the G to IG transition is 3.5 W/m2 or 10 times as much (see my link in #110 above). Put another way, as Milankovitch forcing (?? W/m2) triggered the 6C G to IG change, it was supplemented by 3W/m2 positive feedback from all CHG (same link) and 3.5W/m2 positive feedback from ice albedo. This time with MM doubling of CO2 we will get 4W/m2 of forcing with just 0.3W/m2 ice loss albedo. However there are other potential positive feedbacks like extra methane release which were a relatively minor part of the G to IG transition. Those will increase S. But S estimated from paleo data alone is quite low because the amplification by albedo (never mind dust) is a lot less now than during G to IG (leftmost red squares in KH08 fig 3b). IOW, there is no serious global amplifying affect from Arctic sea ice loss and a corresponding lower sensitivity to primary forcings unless one considers new sources of positive feedback.
  3. Do we know when the Arctic will be sea ice-free?
    Further to Sphaerica's point, the highest atmospheric levels of CO2 achieved in the last 400,000+ years (prior to today's manmade rise) was 297.8 ppmv. We are very, very far into overshoot already. Were it even achievable, the instantaneous cessation of all GHG emissions by mankind, even if held to zero for the next century, might prove insufficient to keep the system from undergoing phase changes due to tipping points already committed to being passed.
  4. Do we know when the Arctic will be sea ice-free?
    22, Mark-US. I disagree. I don't think any particular projection, or the accuracy of any projection is relevant, because no matter what happens, we don't even know at what temperature it's going to be painful. For all we know, if we were able to stop emissions dead today and just live with all of the heating in the pipeline, it may still be too much. In fact, we may find over time that even without more warming in the pipeline, what we have now is too much. So who really cares if AR17's Senario SXb83 projection is 3.76˚C by 2057,or whatever? What matters is how bad the damage is to our environment, and this past year's events demonstrate that we have already played this game for far, far too long. I would argue that looking for better accuracy in such projections (as has been Eric's bent on this recent thread) is just another red-herring, another denial method of avoiding what needs to be done.
  5. AGU Fall Meeting sessions on social media, misinformation and uncertainty
    Igeoffchambers@147: "After at first being told that John Cook was too busy to answer my questions" Now that is a distortion of what was said. Early in the comments, someone else had asked what the best way to contact John Cook would be, and a couple of people (neither named John Cook, and neither being people that could be interpreted as speaking directly on his behalf) had the following comments: "curiousd, John Cook like most of the contributors to SkS is very busy, and not paid for his contributions to SkS, nor for hosting it. I am sure that he attempts to read the comments on a regular basis, so that commenting here or on the SkS facebook page are probably among the most reliable ways to contact him. There is, however, no guarantee. For what it is worth, I have drawn attention to the fact that you are trying to contact him on another forum I know he frequents. There is no guarantee that he'll read that, either, and even if he does he may well be too busy in any event. " [my emphasis] "If you want to know how John Cook interacted with Stephan Lewandowsky on his survey, you best send a querry to John via email. He's a very busy person and no longer has time to read all of the comments posted on SkS. " By your own admission in comment #147,before you could send him an email he did in fact email you. To try to pretend that anyone implied that you would not get a response, as you seem to have done here, would not be discussing in good faith. If you worded that poorly, and did not mean to imply this, then an apology would be a good step to restore some faith. Alternatively, if there is another comment in this thread that you think can be interpreted in such a fashion, feel free to point to it. (Note that I have already looked for all occurrences of the word "Cook", and "busy", and checked to see if any of the moderators comments suggest that something has been snipped.)
  6. Do we know when the Arctic will be sea ice-free?
    "What climate impact will a summer ice-free Arctic bring to the World?" In the UK, possibly very wet summers and higher food prices if this year is anything to go by.
  7. Do we know when the Arctic will be sea ice-free?
    "After my drubbing on ozone there's no point to arguing, just learning." Dale, as a working scientist, I have to respond two ways.. 1) Wah. Science is a *blood sport,* pal, and I *garontee* ya, it get way more brutal than ~anything~ you've had as any "drubbing" you've gotten here. Though true scientists don't often get too caught up in the ad homs, D-K, or confirmation biases traps, we most *assuredly* will rip at another's _work_ like piranhas on a cow crossing the stream...that's just how it works, and it works quite well. To be a scientist, you need a *really* thick skin, and the ability to not take it personally. You've made some--actually, a lot of--classical denier/fake skeptic arguments and if you've read along in this blog for any substantive time (or any credible, "real" science-based blog), you should expect to be called onto the data carpet for them. It's just how it's done, and that leads me to... 2) Having my interpretive head handed to me, on more occasions that I care to admit, *were* the pivotal "learning" moments for me. Keep learning, be willing to admit that maybe, just ~maybe~, the couple thousand climate scientists who live, eat, breathe, sleep, fart, sweat, and argue this for their livings, might just know a few more things about your many-times-debunked stands, and/or have already asked/been asked the same questions, posed the same deniers' arguments, and give them that they likely recognize when goal posts have been shifted. I ain't been around the world, Dale, but I've been around the block, and I'll go out on a limb and say, even the most aggressive here, who 'slice-n-dice' your, and other's, arguments against the known state of the science, most likely just want learning to occur, maybe even more so to those who really are fake skeptics, but might jsut reach a 'tipping point, if I may use the term, into being true skeptics. After all, that is what a true scientist is, and is why they can spot a fake one at a country mile. Ask questions, by all means but if, within that question you assert some D-K claptrap, or an oft-repeated, oft-debunked denier's stand, expect to be drubbed...then move on to the next step in learning. To paraphrase a funny saying: the drubbings will continue until morale improves..;)
    Moderator Response: [DB] To be fair, Dale's question was phrased innocuously and seems genuine; he should be accorded the benefit of the doubt when he does so. If that innocuousness ceases and other things emerge, we should deal with it at that point. We are here to help others learn; this includes all parties who should wish to do so.
  8. AGU Fall Meeting sessions on social media, misinformation and uncertainty
    That's right, Geoff, you have wide latitude to create your own reputation, establish the worth readers will attach to your comments. You claim you understand social science but your ability to describe let alone support your misgivings about Lewandowsky's work belies your confidence. That's a problem you can repair but doing so will require a lot of effort, as you'll see if you follow my tip to obtain a research methods syllabus for a PhD social science program. The fellow who runs Science of Doom is exemplary in terms of showing the potential of autodidactic learning. I wonder if there's a site similar to SoD that's devoted to cognitive psychology as opposed to geophysics?
  9. A vivid demonstration of knee-jerk science rejection
    Just for the record, Eric's initial premise in his opening comment on this thread was:
    Briefly, a large majority of skeptics agree with the 97% of climate scientists on AGW.
    This comment thread has all by itself proven that premise to be 100%, categorically false.
  10. Do we know when the Arctic will be sea ice-free?
    Thanks to those who answered my question. No thanks to 33 & 34. Can't a guy just ask a question to learn? After my drubbing on ozone there's no point to arguing, just learning.
    Moderator Response: [DB] A fair point; point taken. I have issued some guidance to all parties in the response to the comment after this one. This is a place of learning for all who should wish to do so. Everyone please comport yourselves accordingly. Thanks in advance.
  11. AGU Fall Meeting sessions on social media, misinformation and uncertainty
    This article went up on 16 July and attracted 5 comments in the first six weeks. In the week since I posted comment number 6, there have been a further 140 comments. Nine of these were requests by me for simple information about SkepticalScience’s involvement in publicising the Lewandowsky survey. After at first being told that John Cook was too busy to answer my questions, I was finally told that I should contact him via his private email. Before I could do so, he contacted me, offering to answer my questions. In an exchange of eight emails, I learned that Skepticalscience had indeed received a request from Lewandowsky on 28 August 2010, and that Cook had replied that he would put up a post the same day. But Cook was unable to tell me when the post went up or when it was deleted, and he ignored my questions about comments; were there comments to the post, and if so, were they still available? SkS keeps a file of comments deleted by moderators. It seems inconceivable that they would have deleted bona fide comments, even if the post was taken down at the end of the 2/3-month survey period. I ask again; were there comments to the post publicising the Lewandowsky survey, and if so, do they still exist? doug Moderation here is firm but fair. I see nothing in the rules that states that all comments must be of PhD standard.
    Moderator Response:

    [DB] The Deleted Comments bin contains the most recent 60 comments not compliant with the Comments Policy. As such, the current list goes back to 5:02 am on August 25, 2012 (Brisbane, Australia time).

    Only those comments not in compliance with the Comments Policy receive moderation (excepting the helpful response to those occasional comments seeking aid, like this one). Every effort is made to avoid deletion of comments, which is a distasteful last resort. Even then, some participants give the moderation staff no choice but to delete comments.

  12. Do we know when the Arctic will be sea ice-free?
    "But he won't put up with bullshit that runs up against his own expertise, which puts him at odds with Lindzen, Christy, Spencer ..." Well, IMO, that makes him a valuable "skeptic:" I've run into the same, in the car game over the years, and though I hesitate to give them long shrift, as it were, I cannot give them short shrift either. I've experienced folks who were like that, and eventually, if they remain a true skeptic, they ofttimes finally, if highly begrudgingly, move over away from the Dark Side.
  13. Do we know when the Arctic will be sea ice-free?
    funglestrumpet @37 - The Washington Times is like WUWT. Anyone reading it is already a lost cause.
  14. Do we know when the Arctic will be sea ice-free?
    "Ah....a *really* focused denier," perhaps?" I think he deserves the "skeptic" label. He generally refuses to get drawn in on the bigger debate other than rant against the IPCC at times, so it's hard to fully understand his position. But he won't put up with bullshit that runs up against his own expertise, which puts him at odds with Lindzen, Christy, Spencer ...
  15. A vivid demonstration of knee-jerk science rejection
    Sean, " The examples chosen as cherry-picking are not really cherry picking, they just look like assertions to me..." That really is an asinine comment. There is no reason why a cherry pick cannot be presented via an assertion. For example, from our very own Bob Carter, parroted ably by a poor apology for an anthropologist on an adjacent blog: "The planet hasn't warmed since 2001" That is both a (false) assertion and simultaneously a cherry pick. Attempting to redefine what a cherry pick is won't work on this blog.
  16. Do we know when the Arctic will be sea ice-free?
    dhogaza@38: in reading otherr stuff Leif's posted, along with the occasional brickbat aimed at the IPCC, I have begun to come to the understanding that your comment above ends up at: "Here's my hypothesis - Leif's a skeptic who thinks climate science is pretty much crap and so full of errors as to be something to ignore. However, he can't quite bring himself to deny the fruits of his own research ..." Ah....a *really* focused denier," perhaps?
  17. Do we know when the Arctic will be sea ice-free?
    @Dale #31 - I am not a climate scientist, but I read what I can. In the short term (meaning, this may have started already) there is some belief (results from models, interpretation of recent weather patterns) that it leads to slower, loopier Rossby waves. These are the waves in the jet stream that separate temperate air from arctic air. Slower Rossby waves mean that whatever weather we have, will "stick" more often; if it's hot, it will stay hot for longer, and if it's cold, it will stay cold for longer, if it's raining, it will rain for more days. Loopy waves mean that we might get unusual cold spells in the south, and warm spells in the north. I first read about this at Early Warning. Note that some of the recent weather extremes we've seen -- extended cold snaps, extended drought, extended rain and flooding -- are all consistent with this hypothesis, and they're also pretty darn expensive. A disappearing ice cap prompts quite a few medium-term worries. #1, it's strong evidence that our climate models are overconservative. #2, it's a huge climate input that is not included in models, and it's an input that is superficially in the warming direction (reduced polar albedo). #3, there's a fear that arctic methane will be released by a warming environment, and this will lead to additional warming. All these things lead to #4, that we may have completely botched our predictions about how quickly the Greenland ice cap may flow into the ocean, and that sea level may rise more quickly, and that we may see other effects from an infusion of fresh water into the North Atlantic.
  18. Do we know when the Arctic will be sea ice-free?
    "I'm embarrassed to say, but before your post I had not run into/noticed any reference to Leif; by looking at his CV, his data compilation, and reading through his measured, stridently *non* ad-hom responses on WUWT, I am *impressed.* I also notice that, unlike many other posts at WUWT, where someone with verifiably-good chops, viz. climate science/associated fields, chime into to 'conversations,' Tony usually can't resist sticking his smarmy, ad-homm-my comments in....dead *silence* from him on this one. I have a hypothesis: when Watts knows he's *w-w-w-way* out of his league (I know, I know, 'doesn't take much'...) he at least has the smarts to STFU." Here's my hypothesis - Leif's a skeptic who thinks climate science is pretty much crap and so full of errors as to be something to ignore. However, he can't quite bring himself to deny the fruits of his own research ... You'll find him often saying stuff like "even though the consensus as represented by the IPCC is totally wrong, don't make yourself foolish by claiming that changes in TSI have caused recent warming, because TSI hasn't really changed significantly as my own research shows". (that's a paraphrase based on his general position.) He's one of the few posters there who are skeptical and have any credibility and his bottom-line conclusion doesn't differ much from Watts' even though he tries to set people straight on one specific area of denialist beliefs. Watts puts up with the latter because Leif is "reliable" on the big picture, IMO.
  19. AGU Fall Meeting sessions on social media, misinformation and uncertainty
    Geoff, you've seen the gold standard for dilettante critique of Lewandowsky. Your "contribution" doesn't overlap with that space at all, has instead been concentrated on chronological trivia. You say you understand how social scientists work? Ok, by that I take it you're claiming you have a grasp of some branch of social science at the PhD level, even if you've not actually produced a dissertation. That's not impossible but we have only your word for it. Why not show how you're capable of working at the level of a social scientist? Produce a critique of Lewandowsky's work at an academic level, a comment that might be suitable for publication, something relying on formally established alternatives to the methods chosen by Lewandowsky and employing those to show what's wrong with with his work. Don't skip anything, don't imply "trust me," don't leave anything to our imaginations. Failing that, recognize that you don't understand how social scientists work, consider instead being suitably humble and circumspect.
  20. Do we know when the Arctic will be sea ice-free?
    Dana @ 4 The problem is that the general public, on whom the politicians depend for votes, do not know that a body of opinion exists that "Soon and Briggs are not worth taking seriously." So when they see an article such as the one referred to, they have no reason not to believe it, and, therefore, the less reason the politicians feel the need for action. Let's face it, if politicians were going to act responsibly of their own accord, they would have done so by now and we would not even be facing ice-free Arctic summers.
  21. Do we know when the Arctic will be sea ice-free?
    Something is missing from the cryo sciences if the range of prediction is so great. Since we have never had a polar ocean that was ice free, hence never really could study it well. We may have nifty models of ocean heat retention that may help us model - but there are too many loose cannon tipping points: - Strong polar storms (slush makers), - Methane release (how fast?), - Strange new biomasses in the ocean (with seasons of constant sun, what can we predict?), - Coal dust aerosol-fed albedo changes (how dark will it go?) - Oil drill spill risk (just what would a sheen of crude do to ice formation?) - 17,000 Russian casks of high level radioactive waste suddenly uncovered (any studies done for an enclosed ocean?) - a few undersea earthquakes (means open water tsunamis). Lots of questions left.
  22. A vivid demonstration of knee-jerk science rejection
    Sean Lamb - " The examples chosen as cherry-picking are not really cherry picking, they just look like assertions to me..." Just for clarity, quoting from the ever-popular Wiki on the Cherry Picking fallacy:
    ...the fallacy of incomplete evidence is the act of pointing to individual cases or data that seem to confirm a particular position, while ignoring a significant portion of related cases or data that may contradict that position. It is a kind of fallacy of selective attention, the most common example of which is the confirmation bias.
    So yes - arguments that we haven't seen warming in insignificantly short time periods, or at a single temperature station, or that a particular glacier is actually growing - these are all cherry-picking, ignoring the full body of evidence in favor of a tiny subset that matches desired conclusions. In other words, those arguments are fallacies.
  23. Philippe Chantreau at 01:35 AM on 10 September 2012
    A vivid demonstration of knee-jerk science rejection
    SL, John Cook knows very well what cherry-picking is, you're the one who does not seem to understand: the people arguing that "it hasn't warmed since [insert whatever date here] cherry pick a part of the temperature record too short to indicate any kind of trend. It is entirely cherry picking: isolating a period over which the natural variation is much greater than the trend, and over which the natural variation happens to go slightly down. Some on this site have picked periods as short as 6 years to try to make that argument. Strangely enough, the same people often argue that 30 years of satellite records is not enough to detect a real trend in Arctic se ice and that natural variation may very well be the cause of the observed trend there. That's one way you can identify fake skeptics. As for your personal example, the way it is worded can allow you to disguise it as something else than the usual non sequitur, which goes "it has happened for other reasons before so it is happening for other reasons now." The disguise was so transparent that John Cook saw right through it. Nonetheless, to honor the carefully crafted wording of your specific argument, let's examine it as you have it worded: it has happened for other reasons before so we can't be sure that it's not happening again for other reasons now. I'm not sure about a latin name for it, but the argument is flawed and has no place in a rational scientific discussion. Let's imagine that a patient shows up in the ED with wheezing, a cough, enlarged lower extrenmities, who confesses she hasn't taken her "water pills" lately because she ran out and they're too expensive. You could argue that she's had coughing and wheezing before because of common colds and decide not to treat for congestive heart failure because a common cold can't be ruled out this time. That would be utterly stupid but justified according to your reasoning. In fact, even after obtaining lab results showing an elevated BNP and an echo showing enlargement with reduced ejection fraction, you could still argue the same thing, since it can not be absolutely ruled out that she's not coughing because of a common cold. The reasoning is profoundly flawed.
  24. Do we know when the Arctic will be sea ice-free?
    @ mercl #29: I too am proud to be called an "alarmist." In a very real sense, all SkS authors are "alarmists." Many historical figures, including Paul Revere, were alarmists.
  25. Do we know when the Arctic will be sea ice-free?
    @ Bernard J #33: Not only is Dale prone to shifting the goal posts, he simultaneously manages to meander all over the field. As such, the "ostrich" label cannot be applied to Dale because an Ostrich cannot keep its head buried in the sand and at the same time meander all over.
  26. A vivid demonstration of knee-jerk science rejection
    Eric@65: "...I support much of CATO's stand on personal freedom and will not disassociate with them..." Well, there we go. I was reading along with this and one wag stated something to the effect this 'thread would be meaningless.' Au contraire. That statement, coupled with yours, is *perfect* for supporting John Cook's original thesis of this post, and you could not have done a better job of typifying, both "knee jerk" PNS, and the stand of every CATO admirer I've *ever* run into. at least you have the good graces to acknowledge that Pat Michaels doesn't know his....from an ozone hole in the air! At least that puts you ahead of the majority of CATOians I've had the pleasure to "discus" this topic with. As always, I learn as much or more from the comments in a post as I do from the post.
  27. A vivid demonstration of knee-jerk science rejection
    Also, Carrick's finding of one paper that gives a most likely value of 2C rather than 3C (even if the authors themselves had not declared that the value is probably too low) doesn't contradict Lloyd's statement that "Multiple lines of evidence support the usual Charney sensitivity estimate of 3.0° C". Multiple lins of evidence do support this, even if Carrick can cherrypick a small number of papers that suggest it's lower. His effort does fit in with the observations of the original post though ...
    Moderator Response: [DB] All parties: please take further discussion of climate sensitivity to the appropriate thread. Thank you all.
  28. A vivid demonstration of knee-jerk science rejection
    Carrick: "Lloyd Flack: Multiple lines of evidence support the usual Charney sensitivity estimate of 3.0° C. Not really, cloud sensitivity is all over the place and a chief source of uncertainty in equilibrium CS. Reference." Not really, really. The paper referenced by James Annan includes 3C sensitivity in its 95% confidence interval. While it's true the most likely value computed in the paper is 2C, the authors have this to say about their own work: "The estimate of S presented here is likely to be underestimated because the net forcing of the other indirect effects are likely to be negative (Forster et al., 2007)." If they're correct about their own work, we end up back in the 3C ballpark. Their estimate also has a nice tail to the right which isn't really comforting for those of us who, say, wouldn't feel comfortable playing russian roulette even if the revolver has say 30 or 40 chambers rather than 6 ...
  29. Do we know when the Arctic will be sea ice-free?
    Dale at #31. You're not trying to shift the goal posts, are you?
  30. Dikran Marsupial at 22:30 PM on 9 September 2012
    Do we know when the Arctic will be sea ice-free?
    Dale, the key problem is the albedo effect. With the ice no longer reflecting sunlight back into space, it will warm the darker sea water underneath and the earth will warm even faster as a result. I suspect this will be felt most in the long run (centennial scale) as increasing sea levels due to more rapid melting of the Greenland ice sheet. In the short term, it is thought possible that it will affect the jetstream, changing the distribution of weather patterns. In the medium term, more rapid increase in GMST.
  31. Do we know when the Arctic will be sea ice-free?
    What climate impact will a summer ice-free Arctic bring to the World?
  32. Do we know when the Arctic will be sea ice-free?
    I've said similar elsewhere but for the record, and based on the trend in ice volume, I figure that there's a 75% chance of an essentially ice-free summer between 2017 and 2020 and a 95% chance by 2025. If next year's minima continue on the same trend as the last few years, I'd up those percentages to 90% and 99% respectively.
  33. Do we know when the Arctic will be sea ice-free?
    An Ice-free arctic seems very much to me to be a matter of how you define it. For me, it will be when an average sailor can cruise over the geographic North Pole without an iceberg in sight. Given that every single guess or prediction for arctic ice-melt has proven to be way too conservative, then I have no trouble believing that it could happen by 2015. Incidentally, I really don't mind being called an alarmist. An ice-free arctic ocean will be a very alarming situation. The responsible thing to do is ring the alarms.
  34. A detailed look at climate sensitivity
    Eric, Please provide references to the peer reviewed literature to support your wild claims. Papers older than 2007 should reference the IPCC report. Your hand waving claims concerning feedback and the current catastrophic ice loss in the Arctic only illustrate your denial. On another thread (why did you post the same junk on two threads at the same time?) a poster referenced the water vapor feedback which I notice you have ignored. In 1894 Arrhenius did these calculations by hand. You still have not caught up with him. I suggest you read this seminal work. Obviously he understood something you have missed completely. Since you have such a concern about models: Arrhenius predicted over 100 years ago a climate sensitivity of 4.5C. This prediction remains solidly in the high probability range of climate sensitivity. Your 1C is way outside the range. What does that say about your predictions?
  35. Dikran Marsupial at 20:10 PM on 9 September 2012
    Do we know when the Arctic will be sea ice-free?
    agnostic, my statistical model suggested that an ice free Arctic was unlikely to occur before about 2027. Having said which I suspect this years minimum sea ice extent will fall below the credible region of my model (suggesting that my model is probably falsified as being too optimistic).
  36. Do we know when the Arctic will be sea ice-free?
    Agnostic, Unfortunately data from the future is not yet available. The ice is collapsing as we speak. What do we know? We know that in 2007 the IPCC estimated 50-100 years before ice free in the Arctic. The current estimates are 2-40 years. If that doesn't make your blood run cold what will?
  37. A vivid demonstration of knee-jerk science rejection
    Lloyd Flack:
    Multiple lines of evidence support the usual Charney sensitivity estimate of 3.0° C.
    Not really, cloud sensitivity is all over the place and a chief source of uncertainty in equilibrium CS. Reference. ( -Snip-).
    Moderator Response:

    [DB] Yes, really. Charney sensitivity is climate sensitivity, not cloud sensitivity. Thus you set up a strawman argument via goalpost shift and cherry-pick.

    Inflammatory tone snipped.

  38. AGU Fall Meeting sessions on social media, misinformation and uncertainty
    #143 doug_bostrom at 06:29 AM on 9 September, 2012
    Spot-on, Geoff, you're exactly correct...
    But I do trust social scientists, and I do understand how they work. That’s the basis of my criticisms of this paper.
  39. Do we know when the Arctic will be sea ice-free?
    adrian smits @15, There is open water north of 80 degrees right now. Arctic sea ice extent
  40. Record Arctic Sea Ice Melt to Levels Unseen in Millennia
    CBDunkerson thank you for the thorough reply.
  41. Do we know when the Arctic will be sea ice-free?
    All very interesting but … do we know when the Arctic will be sea-ice free in summer? By 2020? By 2030? Informed views anyone?
  42. A vivid demonstration of knee-jerk science rejection
    Gack
  43. A vivid demonstration of knee-jerk science rejection
    What an enjoyable post and threads....
  44. Do we know when the Arctic will be sea ice-free?
    @ 15 Adrian Smits We have records going back more than 50 years: Temperatures North of 80 degree North Unfortunately for your claim they show warming, not cooling. As pointed out above, that warming is limited as long as the polar ice cap remains. However, since other data shows the icecap is melting (getting thinner), you'll really have to provide something more than your opinion to show that it won't ever completely melt.
  45. A vivid demonstration of knee-jerk science rejection
    "Micah, sorry, my fault. I brought up the politics. It's better for me to stay on the sensitivity thread instead." It's good that you did, because it fits with the claim that right-wing politics is a good predictor of denialism. We know your arguments regarding sensitivity are bollocks, it's good to know why you hold on to your views despite an overwhelming amount of science. If you're right, you're not just Galileo ... you're Galileo, Einstein, Bohr, Darwin and others rolled into one.
  46. A vivid demonstration of knee-jerk science rejection
    I was a little amused to see this under examples of "Magnifying dissenters and non-experts" (emphasis mine) "Nils-Axel Mörner,"... "and author of books supporting the validity of dowsing." ... not even trying?
  47. A vivid demonstration of knee-jerk science rejection
    Eric, you seem to forget that when we estimate the temperature sensitivity we are not looking at a process and projecting it forward in time. Rather we are looking at equilibrium points. If we make this disturbance in the heat balance, how much does the temperature have to change to reestablish equality of heat input and output. We can split the temperature sensitivity into four components. The first is the direct effect of the non precipitating greenhouse gases being introduced. The next is the effect of the feedback from changes in precipitating greenhouse gases, water vapor on Earth). The next is other atmospheric feedbacks, primarily clouds. The final one is non atmospheric feedbacks, primarily albedo changes and release from or absorption by natural reservoirs of greenhouse gases. The Charney sensitivity is the product of the first three and the Earth System sensitivity is the product of all four. Let's do a ballpark estimate of the sensitivity. The estimates from complex models will not be greatly different from these.. Now the direct effect of adding CO2 is a straightforward matter of spectral chemistry and radiative physics. It is agreed to be 1.2° C for a doubling of CO2. Given how much water vapor in the atmosphere changes as a result of temperature changes it is again straightforward to calculate its effect. The difficulty is that water vapour is not well mixed in the atmosphere. Still on average we will have the specific humidity increasing to keep the relative humidity roughly constant. Measurements can be and are taken of the changes in concentration that temperature changes bring. This effect is roughly a doubling. This already brings the sensitivity up to 2.4° C for a doubling of CO2, within the usually accepted range of estimates for the Charney sensitivity. Other atmospheric feedbacks is the difficult one. It is composed of circulation changes and cloud changes. The latter look like the big ones and they are composed both of positive feedbacks from trapping head and negative feedbacks from reflecting it back into space. Most estimates from models come up with a small positive net feedbacks but there is a large range including small negative or larger positive net feedbacks. Multiple lines of evidence support the usual Charney sensitivity estimate of 3.0° C. For this to be wrong you either need the effect of water vapour to be greatly in error of you need a large negative feedback from clouds. Do you have any evidence of either of these? For evidence of the water vapour feedback being wrong you need to point to different estimates of that effect with sound justifications for those effects. These need to be calculations from empirical evidence of the water vapour changes. For a large negative feedback from clouds, again evidence is needed. It is hard to estimate the vale of the non atmospheric feedbacks but there is no doubt about their sign. Paleoclimatic evidence support a doubling but since we are starting from a smaller ice cover than the transition out of glacials this is probably a bit high. But there is no way that the albedo changes will be anything but a positive feedback. And as for the release of greenhouse gases from permafrost etc. it's impossible for them to be negative. So evidence please that some of the estimates of these components are greatly in error.
  48. Do we know when the Arctic will be sea ice-free?
    Dagold, try this one: [Source]
  49. It's cooling
    I'm not sure if this is the correct thread for these questions. I'm interested in why the rate of warming in the Northern Hemisphere is faster than the rate of warming in the Southern Hemisphere. Is it due to the following factors: a. The greater proportion of land to water surface in the North. b. The fast-spinning ring of air over the Arctic which affects the jet stream that helps drive the movement of winter storms. c. The localised effect of positive feedbacks such as Arctic amplification. Are these factors correct? Are there any other factors influencing this phenomenon?
  50. Do we know when the Arctic will be sea ice-free?
    @Sphaerica (14), the end-run is interesting from a science perspective certainly.... but we need political action, and that's going to be driven not so much by longterm climate sensitivity but by projections the average person can understand. For A1Fi, IPCC projected in AR4 a likely temperature range at the end of the century. My common sense says that temp range at that date assumed lots more cryosphere albedo in mid-century than it appears we are really going to have. With it removed, (and together with all the other feedbacks we've learned about too) IPCC's upper boundary for A1Fi at the end of the century should go up, yes?

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