Climate Science Glossary

Term Lookup

Enter a term in the search box to find its definition.

Settings

Use the controls in the far right panel to increase or decrease the number of terms automatically displayed (or to completely turn that feature off).

Term Lookup

Settings

All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

Home Arguments Software Resources Comments The Consensus Project Translations About Support

Bluesky Facebook LinkedIn Mastodon MeWe

Twitter YouTube RSS Posts RSS Comments Email Subscribe


Climate's changed before
It's the sun
It's not bad
There is no consensus
It's cooling
Models are unreliable
Temp record is unreliable
Animals and plants can adapt
It hasn't warmed since 1998
Antarctica is gaining ice
View All Arguments...



Username
Password
New? Register here
Forgot your password?

Latest Posts

Archives

Recent Comments

Prev  1501  1502  1503  1504  1505  1506  1507  1508  1509  1510  1511  1512  1513  1514  1515  1516  Next

Comments 75401 to 75450:

  1. CO2 is just a trace gas
    Dikran, Thank you very much for taking the time to respond to my comments. Please let it be known that I am not a mathematician, nor physicist, simply pseudo-philosophical meanderings on my part. Since you bring up Hume, let me state what he is most famous for: The "Is-Ought" problem which states that many people make claims about what ought to be on the basis of observations about what is. However, Hume found that there seems to be a significant difference between descriptive statements (about what is) and prescriptive or normative statements (about what ought to be), and it is not obvious how we can get from making descriptive statements to prescriptive." When climate scientists debate what "is" they are using science; when they conclude what "ought" they have moved into the realm of politics. Although the IPCC may be a good clearing house for information, appeals to authority are in itself a fallacy. If this site engages in Popper's falsification theory then you must know the foundation for which your ought positions rests are speculative at best. I am not denying the nature of GHC, nor the properties of radiative forcing of CO2 etc., but what I am protesting is the ought prescriptions embedded in the science. Respectfully,
  2. Dessler Demolishes Three Crucial 'Skeptic' Myths
    Not surprisingly, considering his educational background, I've found Spencer's economics arguments even worse than his climate arguments. I'm puzzled why he considers himself some sort of economics expert. Spencer is one bizarre guy. Can you imagine the 'skeptic' uproar if James Hansen were to write a book on Keynesian economics or something similar?
  3. Dessler Demolishes Three Crucial 'Skeptic' Myths
    24, 25, 26, Not to mention his recent publication of Fundanomics : The Free Market Simplified, as well as promoting it all over his blog.
    Best-selling author Roy W. Spencer looks at the fundamental driving force that propels a society to ever higher levels of prosperity, generation after generation: People having the freedom to provide as much stuff as possible to each other that is needed and wanted...no matter what that stuff happens to be. Everything else in economics is details.
    Yup. He's everything I look for in a scientist. At least he can't be accused of having a hidden agenda.
  4. Conspiracy Dog-whistling about GRL and the New Dessler Paper
    How about changing the headline from "Conspiracy Dog-whistling..." to "Conspiracy web spinning...?
  5. Dessler Demolishes Three Crucial 'Skeptic' Myths
    "I view my job a little like a legislator, supported by the taxpayer, to protect the interests of the taxpayer and to minimize the role of government." While many people have pointed out that this jaw-dropping statement about how Spencer views his job as a *scientist* is totally out of whack regarding the job description that goes along with a research position at a university ... I've not seen anyone point out the arrogance and hubris implicit in his claim that his job is somewhat like that of a legislator *elected by the people*. The taxpayers didn't vote for you and you have no basis for arguing that you're acting in their interest.
  6. Republican Presidential Candidates vs. Climate Science
    Sorry... I was responding to Jonathon and Badger's comments on Rick Perry. I've just got Spencer on the brain this week. But I think the comment still holds.
    Response:

    [DB] I can fix it if you like.

  7. Republican Presidential Candidates vs. Climate Science
    The Galileo analogy is misapplied not (IMHO) because of the relationship between the "establishment" and a purveyor of new ideas. With Galileo he was presenting a new and elegant concept that answered nagging problems with the established thinking. It was the problem of "wandering stars." With Spencer we have the opposite situation. He's trying to, in essence, remove CO2 from the climate equation. While CO2 neatly explains a wide variety of aspects of the Earth's past climate (snowball Earth, glacial-interglacials, etc.) by removing this he is leaving all those questions unanswered. He's trying to remove the keystone without offering us anything that fits better in it's place. That is where Spencer fails (along with Lindzen and others). Spencer is the guy who, many decades after Galileo's ideas became accepted science, was trying to say that the Church actually was correct about an Earth centered universe.
  8. Dessler Demolishes Three Crucial 'Skeptic' Myths
    Aprirate @24, Really? I think that you are being coy. Surely you have taken the time to read Spencer's blog and his musings elsewhere. But I'll humour/help you since you can't be bothered to make the effort yourself. Look at the stark contrast of the following two statements in which the person describes what they are striving for: Roy Spencer: "Nicholas, I would wager that my job has helped save our economy from the economic ravages of out-of-control environmental extremism. I view my job a little like a legislator, supported by the taxpayer, to protect the interests of the taxpayer and to minimize the role of government." [Source] Andrew Dessler: "I went into science because I wanted to devote my life to the search for scientific knowledge and to make the world a better place. That's the same noble goal that motivates most scientists. The ultimate dream is to make a discovery so profound and revolutionary that it catapults one into the pantheon of the greatest scientific minds of history: Newton, Einstein, Maxwell, Planck, etc." [Source] EOS.
  9. apiratelooksat50 at 05:24 AM on 9 September 2011
    Dessler Demolishes Three Crucial 'Skeptic' Myths
    Albatross at 22 "I would also advise being highly skeptical of work by a scientists who is so deeply entrenched in ideology and politics as Spencer is. Dessler is using science as a tool better understand how our climate system operates, Spencer is using science for altogether different reasons." Will you enlighten me on this, please? Thanks
  10. Republican Presidential Candidates vs. Climate Science
    Badgersouth, A little history clarification. It was the scientific scholars of the time, mostly Jesuits, who convinced Pope Urban to charge Galileo with heresy. Galileo's greatest offense was angering his colleagues, whom he regarded as inferior. While this was probably so, they wielded much influence at the time, and persuaded Pope Urban to act "in defense of the church." Many of this friends, including Pope Urban, urged Galileo to use a little restraint, but this just caused him to proclaim louder. I admit to not having followed Gov. Perry to know much about his scientific background.
  11. Republican Presidential Candidates vs. Climate Science
    “The most striking part of the first full-blown debate in the Republican primary was the total rejection of science. “In a surreal scene near the night's end, Gov. Rick Perry likened the people denying global warming science to Galileo. To observe that he has that history exactly backwards -- it was the Church that accused Galileo of heresy in 1633 for scientific theories which were on the right track -- is merely to observe that Perry's substantive errors come with their own stylistic snafus. Perhaps that is fitting. More consequential, however, was the answer that Perry failed to provide.” Source: “GOP Debate: From Birthers to Earthers” by Ari Melber, Huffington Post, Sep 8, 2011 To access this article, click here.
  12. Dikran Marsupial at 03:43 AM on 9 September 2011
    Conspiracy Dog-whistling about GRL and the New Dessler Paper
    Further to Stephen's excellent comments, there is another factor that may have facilitated a rapid peer review, which was that Spencer made sure his paper got a lot of media attention. This means that many potential reviewers would already have read Spencer's paper quite recently, thought about it, and probably noticed some of the errors in it, even before they received Dessler's comment to review. Performing the review while it is still fresh in your mind is much easier, so the reviewers would be only be making life more difficult by delaying.
  13. Conspiracy Dog-whistling about GRL and the New Dessler Paper
    Didn't Said and Wegman get a paper through review in 2-3 days? Anyway, I don't see what the fuss is about. The journal I edit for has a fast-track procedure that can turn papers around in 2-3 weeks - and it does not have the reputation for fast turnover that GRL has. Everything does have to go right to meet that deadline (editor identifies reviewers quickly, reviewers agree quickly, reviewers review quickly, everyone agree accept with minor changes, changes are made). But the key point is that "fast-tracking" in and of itself is not an indication of insufficient review. The thing that slows paper review the most is the conflicting priorities reviewers and editors have. If a journal feels a paper is topical, you can speed the review process enormously simply by paying more attention than usual to each of the steps, rather than letting distractions delay the process. If you give a paper high priority, it's amazing how fast a decision can be made. Another thing that can really speed a paper through the process is if it is fairly straightforward. Desslers paper actually fits into that category in that it is a critique of another high profile paper that has obvious flaws. That sets a pretty low bar there. Another thing that would make it easy to review is that it refers to a single analysis (rather than a body of literature). That means the critiques can be evaluated in a pretty straight forward manner by the reviewers.
  14. Conspiracy Dog-whistling about GRL and the New Dessler Paper
    Dikran @5, Yes, and those inconvenient facts are ignored by the "skeptics". I say "ignored" b/c Pielke et al. know very well that GRL strives to produce a quick turnaround for authors . Hence the brevity of the manuscripts. But hey, you can always count on the "skeptics" to give birth to yet another myth and conspiracy theory.
  15. Conspiracy Dog-whistling about GRL and the New Dessler Paper
    "And somewhat surprisingly, Roger Pielke Sr. jumps into the fray" Why surprisingly? RPSr has been, in essence, Watts's sponsor from the beginning. Note that RPSr's and Watts's comments are very similar.
  16. Dikran Marsupial at 03:21 AM on 9 September 2011
    Conspiracy Dog-whistling about GRL and the New Dessler Paper
    Isn't the whole point of "Letters" journals (such as Geophysical Research LETTERS) to provide rapid turnaround on short research notes on timely topics. Surely Spencer and Pielke know this? Perhaps it is because GRL keeps so quiet about its policies? "GRL is a Letters journal; limiting manuscript size expedites the review and publication process." Sound of straws being clutched at (but in vain).
  17. Conspiracy Dog-whistling about GRL and the New Dessler Paper
    Once you have 'seen' the conspiracy it can explain anything. Even the mundane.
  18. Conspiracy Dog-whistling about GRL and the New Dessler Paper
    Marco @2, Care to elaborate please?
  19. Conspiracy Dog-whistling about GRL and the New Dessler Paper
    I think we have identified one of the reviewers of the Dessler paper :-)
  20. Republican Presidential Candidates vs. Climate Science
    One great moment in the 'debate' was when the moderator asked Perry which scientist he was referring to when he said the science wasn't settled. I was waiting for him to drop a 'Spencer bomb' but he just waffled. So 'scientists are coming forward every day to question AGW', but he can't name one.
    Response:

    [DB] I keep looking for my "like" button for this comment...

  21. Conspiracy Dog-whistling about GRL and the New Dessler Paper
    In the first paragraph, "rebuked" should probably read "rebutted".
    Moderator Response: [grypo] Thanks. I just changed it to 'criticized'. I'm just trying to show that this entire debate is moving rather quickly, not trying to infer that any conclusions have been made yet.
  22. Dessler Demolishes Three Crucial 'Skeptic' Myths
    What's too bad is that there may have been some good science in what Spencer was trying to do, but he (as usual) took it way too far as he tries to use every little piece of research he does to claim he's killed AGW theory, when he's done nothing of the sort. I also think Spencer is getting his come-upins for his publishing tactics. He's trying to get his work published essentially with as little peer review as possible. In that he's missing the opportunity to understand his own research better by having to answer hard questions from knowledgeable reviewers. The result is the tenuous results he's getting have to be played out (reviewed) through response papers.
  23. Dessler Demolishes Three Crucial 'Skeptic' Myths
    Critical Mass @17, "After reading the attack on Spencer" What attack? Where? By whom? People seems to confuse scientific debate and discussion with attack. Pointing out someone is wrong or noting problems with their methodology does not "constitute" an attack. The "attacking" going on here by "skeptics" and deniers of AGW on the integrity and advancement of science. Who to believe? The multiple independent lines of evidence that point towards the theory (not hypothesis) of AGW. Consider too the sage words of Dr. Nielsen-Gammon (former editor of the prestiguos Journal of Climate): "The only viable explanation for the glacial-interglacial cycles (not all that stable, really) involves a bunch of feedbacks (ice-albedo, water vapor, CO2, and methane), and there’s ample geological and ice core evidence for all of them. Why would anthropogenic CO2 now be the first forcing that doesn’t engage net positive feedbacks?". and there is indeed good support for a positive feedbacks in the literature, including positive cloud feedbacks see here and Dessler (2010) that I linked to above @20, and also the findings from Screen and Simmonds (2010): "Changes in cloud cover, in contrast, have not contributed strongly to recent warming. Increases in atmospheric water vapour content, partly in response to reduced sea ice cover, may have enhanced warming in the lower part of the atmosphere during summer and early autumn." I would also advise being highly skeptical of work by a scientists who is so deeply entrenched in ideology and politics as Spencer is. Dessler is using science as a tool better understand how our climate system operates, Spencer is using science for altogether different reasons.
  24. Dessler Demolishes Three Crucial 'Skeptic' Myths
    Camburn: "Also, the use of the three models with the highest/lowest sensativity is not cherry picking." You know, having worked with real world data in my life, suspicious outliers are what get tossed out, not data that fits with other real world observations. You're standing things upside down. Certainly if some models are going to be tossed, the outliers - particularly given that they don't do a good job of modeling ENSO-like events - would be those that would be tossed. But of course, best would be to do what Dressler did - look at all the model outputs and take a stab at understanding why some match observational data during ENSO events than others (the answer that those that best model ENSO events in the first place do so is no surprise, of course). The defense of Spencer has reached the point of being pathetic. Personally, I welcome it. First we saw the denialsphere defending Wegman's plagiarism on the grounds that "it's just plagiarism", now we see Spencer's cherry-picking being defended on the grounds that cherry-picking isn't cherry-picking because it's "logical cherry-picking". Sheesh. Keep at it, please.
  25. Dessler Demolishes Three Crucial 'Skeptic' Myths
    Camburn @18, Please stop make unsubstantiated claims and talking through your hat. As per previous statements made by you on this thread you clearly do not understand the papers. And you have avoided answering the questions that i addressed to you here. I am glad though that you have acknowledged that "skeptics" are making comical and unsubstantiated claims. I would advise you to read Chapter 8 of the latest IPCC report, it is a great overview, and explains the models developed by numerous research groups from around the world. The point that you and people like Spencer continue to ignore is that several datasets also indicate a climate sensitivity near +3 C for doubling CO2. But Spencer, like Lindzen, is focussed on the models (that angle seems to be their last ditch end game), because, in his mind they are a cornerstone of the IPCC dogma. The man is paranoid and entertains conspiracy theories on a daily basis-- go to his blog if you don't believe me. But back to Spencer's dear models. Funnily enough, the three models that compare best with with observations in his data and Dessler's (you know three models Spencer and Braswell ignored) have equilibrium climate sensitivities of +3.4 C (GFDL-CM2.1), +3.4 (ECHAM5/MPI-OM) and +3.2 C (MRI-CGCM2.3.2), respectively. But that is not really relevant to this discussion, but given that Spencer is so focussed on climate sensitivity it is odd that he failed to discuss this at all. But it gets a little more interesting when one looks at the cloud feedbacks for the above models as shown in Dessler (2010), and that is relevant to this discussion: GFDL-CM2.1: Short term cloud feedback +0.34 W m-2 (+/- 0.20), long-term feedback +0.81 ECHAM5/MPI-OM: Short term cloud feedback +0.74 W m-2 (+/- 0.20), long-term feedback +1.18 Results for the cloud feedback in MRI-CGCM2.3.2 were not reported in Dessler (2010), but the both the above models have both positive short-term and long-term cloud feedback. With all that said, is Dessler (2011) the final word on this, probably not. But what is becoming increasingly clear is that a negative, nevermind strong negative feedback, from clouds is highly unlikely, but Dessler is open minded enough to say that: "A small negative feedback is possible, but one large enough to cancel the climate’s positive feedbacks is not supported by these observations." Dessler also includes confidence intervals (something Spewncer and Braswell did not do). Now Dessler is in fact a good scientists who is really interested in the pursuit of truth, the very antithesis of Spencer.
  26. Dessler Demolishes Three Crucial 'Skeptic' Myths
    critical mass - the difference is that Dessler's '20 fold' value is peer-reviewed. Spencer's '10 fold' calculation was posted on his blog, and the commenters have already found several errors in it. The main disagreement is in ocean heat content - Dessler confirmed his calculation with two different data sets, one of them being from a "skeptic" paper published by Douglass and Knox. If anything, the value is at least much closer to Dessler's than Spencer's. Camburn - excluding more than half of the model runs, including those which best modeled the data, is by definition cherrypicking. Once again I ask that you try to actually make substantive comments rather than baseless disparagements like "comical." Saying "Dessler is a big poopy head" doesn't add anything to the discussion.
  27. ConCERN Trolling on Cosmic Rays, Clouds, and Climate Change
    Tristan#18: "muons" By using a 3.5 GeV pion beam, CLOUD is on the low edge of GCR energies and the high edge of solar cosmic ray energies. Pions decay to muons (in this case, anti-muons from positive pions). Nigel Calder's comment that the CLOUD beam produced 'stronger cosmic rays' than 'background' is false. To me, this is a glaring flaw in the experiment - if low energies cause the observed nucleation, then why aren't there all clouds, all the time? Since the climate-GCR connection originated with cosmogenic Be10 anomalies, why didn't CERN use their proton beam and thus simulate the kind of GCR that causes spallation? Similarly, the Danish group's claim that they saw the 'same effect' using a sodium gamma source should be very troubling (see the link under 'energy question' here).
  28. Dessler Demolishes Three Crucial 'Skeptic' Myths
    critical mass@17: Spencer is not the only one who shows that the 20 fold is .....a large large stretch to say the least. Also, the use of the three models with the highest/lowest sensativity is not cherry picking. And another point is, which model is correct? Of all the models, which are up to what....18 now? The claims by skeptics and AGW folks about these sets of papers is getting almost to the point of comical. I can only suggest to all to re-read the papers carefully again. There are claims all over the blogs from both skeptics and AGW that do not bear credence when examined.
  29. ConCERN Trolling on Cosmic Rays, Clouds, and Climate Change
    18 Tristan - give them time; eventually someone'll suggest it's all down to cloud nucleation by neutrinos.
  30. Medieval Warm Period was warmer
    Tristan. One easy thing to keep in mind when mentally testing 'skeptic' posturing about the MCA/MWP. These same people will try to argue in the next breath/ paragraph/ thread that there's no problem with CO2 release because the climate has little or no sensitivity to forcing by GHGs. They fail to notice that an argument in favour of a global, higher-than-now temperature for the medieval period is also an argument in favour of (very) high sensitivity to any forcing. You might not want to advance this point while you're still feeling your way through the science. But it's a handy reality check when you read such things.
  31. Republican Presidential Candidates vs. Climate Science
    The first major GOP debate to feature firebrand Rick Perry went pretty much as expected on the green front: lots of calls for more drilling, plenty o' climate change denyin', and ample confusion about science itself. Source: “GOP Debate Fireworks: Perry Doubles Down on Climate Denial, Huntsman Says GOP Can't Run from Science,” TreeHugger, Sep 8, 2011 To access this informative article and video, click here
  32. Dessler Demolishes Three Crucial 'Skeptic' Myths
    After reading the attack on Spencer I went and had a look at his site. Not exactly a presentation "good bad and ugly pics" you would find in a science site, however Spencer is saying that Dressler is wrong about the 20 fold error claimed found in Spencer's paper. Spencer claims that Dressler is out by 10 fold in his calculation. How do we know who is right here with these competing claims to consider? Stig Mikalsen puts it aptly : "Also, in my view, comments here are much more valuable if they tone down the mocking and the personal and concentrate on the science and a more "neutral" language. A science blog this is".
  33. Republican Presidential Candidates vs. Climate Science
    Badgersouth - "The articles that I provide links to further amplify and reinforce the quotes provided by Dana in his article." And I would know that, um... how? Time is infinite, but I am finite. I try not to click on every link that appears, but rather only those I have a reason to follow up on. Sorry.
  34. ConCERN Trolling on Cosmic Rays, Clouds, and Climate Change
    Marcus, There has been a slight cooling effect recently, albeit it has not been significant leading some to call it a "lack of warming." However, many of us relate that to the recent La Ninas (2008 & 2011). The cooling was somewhat stemmed by the strong EL Nino of 2010. If the GCRs do enhance tropical cloud formation, then that could greatly impact ENSO. As Chris G states, these are just cycles. However, we must be careful not to misread the increasing (or decreasing) cycle stage as anything other that just that. I think RickG says it best with his emphasis on the conclusion of the CLOUD press release. The research to date neither proves nor disproves the GCR effect on climate.
  35. ConCERN Trolling on Cosmic Rays, Clouds, and Climate Change
    Has anyone actually suggested solar cosmic ray muons cause cloud nucleation?
  36. Dessler Demolishes Three Crucial 'Skeptic' Myths
    Stig Mikalsen as a general rule, I agree with you that we should not rely on any single paper untill it has been "digested" by the scientific community. In this case, though, Dessler confirms what has been thought by many for a long while, he doesn't try to subvert the accepted knowledge like Spencer or Lindzen. In other words, while Dessler work is a very welcome bit of science, climatologists could live without it, there was no open question awaiting an answer.
  37. Pete Dunkelberg at 21:44 PM on 8 September 2011
    Dessler Demolishes Three Crucial 'Skeptic' Myths
    In addition to the short term data, SB11 and also Lindzen have a little problem with conservation of energy. Read more at Rabett Run. Any version of "the climate is warming itself for decades on end" runs into this.
  38. Dessler Demolishes Three Crucial 'Skeptic' Myths
    I haven't been around for a while, and this is off-topic, but... Congratulations to John Cook for winning the Eureka Prize for the Advancement of Climate Change Knowledge. Fully deserved.
  39. Dikran Marsupial at 21:16 PM on 8 September 2011
    CO2 is just a trace gas
    Albatross, Rob, Sphaerica, muoncounter, many thanks for the suggestions and links. My basic idea was to implement the electromagnet idea with a knob the user could play with to change the current and a trace (with a running mean) to show the effect of the forcing. Learning about the maths would be half the fun for me as I've never studied mechanics (I'm O.K. with differential equations though which is a useful start). Hopefully I can persuade Mrs Marsupial to help with the programming (I only like numerical programming rather than user interface stuff).
  40. OA not OK part 20: SUMMARY 2/2
    Doug thanks. just downloaded both Orr and IPCC 2009. good reading for the week end. :+) Tony
  41. Dessler Demolishes Three Crucial 'Skeptic' Myths
    It may be that "It's difficult to exaggerate the impact of Dessler's findings". But it is always wise to show a little caution until the findings are robust. Dessler's paper DO show that SB and LC have serious problems. But it is also POSSIBLE at this stage that Desslers' paper also may contain some problems. If it does, then this post may be a little too reliant on the one paper. Also, in my view, comments here are much more valuable if they tone down the mocking and the personal and concentrate on the science and a more "neutral" language. A science blog this is. That said, keep up the good work. Lots of objective and valuable information on this site.
  42. Medieval Warm Period was warmer
    Thanks a lot folks, I love learning about all this stuff
    Response:

    [DB] In addition to using the omnipresent Search function in the upper left corner of every page here, one can also examine skeptic arguments by Taxonomy.  However, much information is contained in blog post form here which may not be found in the rebuttals, so the search function is best overall.

    For example, a search of the term "Medieval Warm Period" returns the following:

    Search Results

    Skeptic arguments matching the search 'Medieval Warm Period':

    Blog posts matching the search 'Medieval Warm Period':

  43. Dessler Demolishes Three Crucial 'Skeptic' Myths
    XKCD's racecar on a train cartoon is a brilliant take on D-Kish style occurences. The alt-text would offer the perfect self-test for anyone like Spencer willing to actually abide by it: I mean, what's more likely -- that I have uncovered fundamental flaws in this field that no one in it has ever thought about, or that I need to read a little more? Hint: it's the one that involves less work.
  44. Medieval Warm Period was warmer
    #34 Tristan: The difficulty skeptics have with the MWP (MCA) is that they've heard all this anecdotal evidence of NW Europe being warmer, or Greenland being particularly pleasant for the Vikings (less unpleasant would be more appropriate), and they conflate that with the idea that therefore the whole world must have been uniformly much warmer during the MCA. To our best knowledge (see scaddenp's link), warming wasn't uniform, either in space or in time, and so globally it was relatively modest. Some places were warmer, others cooler or not much different. IIRC, Greenland's peak warmth occurs a couple of hundred years before Britain or Central Europe experienced peak warmth. At the same time, other areas were cooler and so global temperature just wasn't as much warmer as some skeptics would like to believe, see Mann et al 2009. The Little Ice Age experienced similar variations, in that it's most pronounced over NW Europe and the N Atlantic region, driven most likely by some increased volcanic activity and reduced solar activity. Where do most of our familiar cultural / historical records of the Western world emanate? NW Europe, hence at least part of the entrenchment of the MWP/LIA ideas. Today's warming is (relatively) much more globally uniform by comparison, and so there's much more of a signal in global mean temperature. Our best idea of climate forcings over these periods (solar/volcanic activity, then the recent CO2 spike) reflect these global patterns. The overall pattern globally is one of relatively subdued changes over the MWP/LIA, then a large rise through the present, reflecting the forcings. Skeptics complain about the 'missing MWP' because they want it to be there, large and proud, in global temperature records. The evidence suggests that it's only large and proud in some parts of the world, some of the time, disappointing the skeptics... again. Oh, and if that palaeo evidence were to be overturned and the MWP was globally really strong, what is the main implication? Very high climate sensitivity, not what skeptics want to hear!
  45. Dikran Marsupial at 17:43 PM on 8 September 2011
    CO2 is just a trace gas
    Dan69 wrote: "That being said, my understanding is that the Lagrangian math works great for 2 points, but becomes infinitely complex when you add 3 or more points to the equation." I think you are referring to the N-body problem there, which is a different problem (as for the double pendulum there is a physical constraint on the distance between hinges. Also for the double pendulum, from what I have read the Lagrangian is used to set up the differential equations which are then solved numerically. If there was an analytic solution (i) it wouldn't be a chaotic system and (ii) the programmers would have used it. For General Circulation Models, the techniques used are essentially those developed for fluid dynamics, and work very well in a wide range of other applications, the apparent complexity of the problem is not as big an issue as you might think (GCMs don't work by predicting weather, but by simulating weather with statistically similar properties). So the N-body problem has very little to do with either double pendulums (pendula?) or climate modelling. "The only point I see is in the politics of controlling output of man-made CO2 as the primary focus on policy, not the truth behind what is actually going on with the climate." It is perfectly appropriate for policy to be focussed on controling carbon emissions. CO2 is not the only forcing, but it is an important forcing and the one that we have been using substantially since the start of the industrial revolution. We can't legislate about solar forcing, the Sun isn't subject to policy; carbon emitters are. The truth behind what is actually going on with the climate is well set out in the IPCC WG1 Scientific Basis. To a first approximation, the summary for policy makers is essentially "anthropogenic carbon emissions will cause global surface tempetratures to rise significantly over the next century; if you don't want that (and the resulting impacts) to happen, then we need to stabilise atmospheric CO2". "Clearly,climate is a complex ball of wax and suppressing one part, without a full understanding of the unseen consequences, would have possibly worse outcomes." Nobody is suppressing anything. As I pointed out earlier, "skeptics" (note the use of "") frequently claim climatologists are suppressing something, or they don't know about something, or that they know about something but pretend it doesn't exist. However that doesn't make it true and simply reading the IPCC WG1 report demonstrates that generally it isn't true. However that doesn't stop the gullible from swallowing it hook line and sinker. Secondly, it is impossible to have a full understanding of anything regarding the real world, we can only have imperfect or uncertain knowledge. We have know this since the work of David Hume. Following your logic we would never be able to draw conclusions about anything or plan our actions. However there is a thing called "statistical decision theory" which provides a provably optimal way of planning under uncertainty, which is what rational people do. "I also defer to Quine-Duhem theory with regards to the unknown variables present." I had to look that one up. Essentially it says that hypothesis testing is always subject to assumptions, something that all scientists know. However mostly those assumptions remain unsaid as they are part of the dominant scientific paradigm of the day. However it is not a reason to ignore the results of the hypothesis test. There is always residual doubt over the truth of any physical proposition, but it would be absurd to use that residual doubt as a reason not to act when the balance of the evidence suggests that action is required. Lastly, I think there is a radiative competent as to the upper limits of what CO2 can affect. " ISTR going over this recently. The radiative forcing from CO2 is logarithmic in the concentration, so no, there is no limit as the limit of log(x) as x tends to infinity goes to infinity.
  46. Medieval Warm Period was warmer
    Tristan - I doubt facts would have much influence skeptics pushing this argument but you can see these at the paleoclimate chapter in the IPCC report, specifically this section for temperature reconstructions and model simulations of this period. However, more recent work has shown the MWP (better called MCA) to be rather more complex than simple global event (see this paper for instance) so appears a dynamical component involved as well.
  47. Medieval Warm Period was warmer
    Apologies in advance if I've failed to find it, sometimes I have trouble navigating this site: I keep hearing from the skeptic corner that the MWP isn't reflected by any of the IPCC's models and therefore the models are completely useless. Is there a page that examines this issue?
  48. Pete Dunkelberg at 14:45 PM on 8 September 2011
    Tar Sands Impact on Climate Change
    What about the rhetoric of rejection? "Nothing matters, it will all be developed anyway. Atmospheric CO2 will probably go up to 1000 ppm and human population plummet no matter what anyone does." Some people think human action matters. This pipeline is symbolic of whether we start heading off 1000 ppm now or wait until after CO2 reaches 450. If we stop the pipeline and start heading in the right direction and show some leadership all of a sudden, it is not at all certain that all the tar will be burned. Stopping it or not will be symbolic in addition to the direct effect on barrels burned. Symbols matter.
  49. Pete Dunkelberg at 14:34 PM on 8 September 2011
    Tar Sands Impact on Climate Change
    This article: http://www.tarsandsaction.org/signup/dechristopher-share/key-facts/ will make you not want this pipeline. For starters:
    * Keystone XL is an export pipeline. According to presentations to investors, Gulf Coast refiners plan to refine the cheap Canadian crude supplied by the pipeline into diesel and other products for export to Europe and Latin America. Proceeds from these exports are earned tax-free. Much of the fuel refined from the pipeline’s heavy crude oil will never reach U.S. drivers’ tanks.
  50. The human fingerprint in the daily cycle
    139, Norman, I hadn't realized that you'd supplied that same link. I found it later for an entirely different purpose, when trying to google "atmospheric temperature altitude hour" to try to determine if there's any observational evidence of how the atmosphere warms or cools through the day... although I'm sure I must have looked at it when you sent it. I did find the paper you referenced. Here is the link. I'll have to read it. It looks interesting. Briefly parsing the section you quoted, it does not seem to have an obvious impact on DTR. It seems instead to be arguing for a factor in lower climate sensitivity (i.e. that a warmer atmosphere has an enhanced ability to "pass through" additional heat coming from the surface). But it clearly complicates the picture I've painted and warrants reading. FYI, this link is to a PDF for what appears to be a slideshow on the same subject by the same author (Huang). This seems to be a favorite topic of his. Searching for "Planck damping" and "Planck effect" primarily yield papers by Yi Huang, including his dissertation.
    Response:

    [DB] Fixed link.

Prev  1501  1502  1503  1504  1505  1506  1507  1508  1509  1510  1511  1512  1513  1514  1515  1516  Next


The Consensus Project Website

THE ESCALATOR

(free to republish)


© Copyright 2024 John Cook
Home | Translations | About Us | Privacy | Contact Us