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Comments 104401 to 104450:

  1. Philippe Chantreau at 16:58 PM on 17 November 2010
    Naomi Oreskes' Merchants of Doubt Australian tour
    So Seitz did not conduct any research, he just oversaw a propaganda campaign and allowed his name to be used for credibility. That's supposed to be better?
  2. Naomi Oreskes' Merchants of Doubt Australian tour
    kdkd @71, Good points. Here, in my opinion, on this thread we have a perfect example of the techniques used by "skeptics" to deflect and misinform-- techniques which Oreskes and Conway speak to. The "skeptics" supporting Seitz have not read this memorandum, or this news release.
  3. Naomi Oreskes' Merchants of Doubt Australian tour
    Poptech seems unable to deal with this part of my argument: "Typical so-called-sceptic approach of taking a position, emphasising a very small part of the argument (without examining the validity of the argument in the broader context) and then using that to generalise to the whole argument without justifying your case properly." Poptech's lack of a broader context is really the knockout blow to his position
  4. Philippe Chantreau at 16:31 PM on 17 November 2010
    Climategate a year later
    Another non story relegated to oblivion as reality goes on.
  5. Are ice sheet losses overestimated?
    John Kehr, I would like to know how you substantiate your claim that the current ice loss is comparable to during the MWP. I see no evidence that the rate of change since 2006 is reproducible during the MWP. The following study : http://www.igsoc.org/annals/50/50/a50a028.pdf Finds similar surface mass balance melting during the early 1920s to 1930s as up until 2005, however dynamical ice processes have dominated the ice loss trends since 2006. See Van Den Broeke et al. 2009 or Khan et al. 2010 for example. This year had the largest ice losses for Greenland ever recorded (see my last link for the arctic report card). Prior to 2006 the ice losses were within the realm of the absolute upper end of natural variability but post 2006 and up to 2010 we have seen huge accelerations in glaciers in both Greenland and Antarctica. This does NOT open the possibility that the current warming is natural in cause. The current warming is showing that if the current ice loss continued, we would see sea levels which were globally MUCH higher than during the MWP. If the acceleration occurs as it is going we will see a minimum of 5 times the amount of sea level rise as found during the MWP. That to me does not seem to support your conclusion. Like I said, Grinsted et al. 2010 show that if current temperature (up to 2009) were maintained then SLR would be nearly 2x that of during the MWP by the time the oceans reach equilibrium. Many glaciers in the NH did experience significant retreat during the 1940-1950 period but far less than during the most recent warm period across most regions. A good example is the complete disappearance of ice caps in the high arctic (Anderson et al. 2008) or the significant ice losses in Alaska, Norway, Yukon, Svalbard, and Iceland which are all greater than those experienced during the previous warm period. "If the sheet loss was as great in 1940, then it is very hard to say that CO2 emissions have caused an "unnatural" rate of loss today" This statement is actually very much the opposite and works against you. Considering we know the major mechanisms which caused the early to mid century warming in this region, we can analyze whether the same mechanisms are causing the current warming. We know that the previous warm period involved a lull of volcanic activity, high solar irradiance and a positive AMO. Whereas now we have GREATER ice losses with lower solar, higher volcanic activity and a positive AMO. We would therefore expect that the previous warm period would be at the upper end of natural variability because of the "perfect storm" of natural contributors and yet the ice losses then were lower than now without the same contributors.
  6. actually thoughtful at 16:10 PM on 17 November 2010
    Solving Global Warming - Not Easy, But Not Too Hard
    The Ville: "I use a green electricity tariff (i'm all electric). I have managed to reduce my energy consumption by about 60% by just doing a few simple things which haven't had a big impact to the quality of life." Do you mind if I ask what those few simple things are? I would enjoy paying for 60% less electricity. Can you explain what "I use a green electricity tariff" means? thanks, Tom
  7. Are ice sheet losses overestimated?
    John Kehr, WRT: "This leaves open the possibility that the current warming is natural in cause. " I don't think so. What is the cause in modern times other than AGHGs? What would prevent CO2 from behaving, with regard to the wavelength of photons that in absorbs and emits, in the atmosphere differently than it does in physics labs? Just because it's not clear who killed Oetzi, does not mean that we don't have a pretty good idea who killed Ghandi.
  8. Climategate a year later
    And for those who get all uppity about how "rude" or "aggressive" the remarks within some of those emails were, Arthur Smith has some extracted comments from other discussions. And remember, these aren't private comments, they're directed to editors of journals. I've made some guesses at what might have been said about some of these papers in private, you can do your own guessing. http://arthur.shumwaysmith.com/life/content/the_nothing_that_was_climategate
  9. Naomi Oreskes' Merchants of Doubt Australian tour
    Muoncounter @66, Yes, this is silly, and it would be laughable if it were not such a serious matter. I fear that you may be wasting your time-- there is no sense arguing with those who endorse the irresponsible, criminal even, behavior of those involved in fabricating doubt concerning the existence of the link between smoke and cancer-- a link that was known to exist even according to research carried out by the tobacco companies. Bizarre how some, despite the facts to the contrary (including court rulings), insist on defending those who were involved in delaying taking action against tobacco corporations. Disturbing too how some of the same players are now involved in delaying taking action on anthropogenic climate change. Some seem to think that we live in a world where our actions have no negative consequences or repercussions. Perhaps Poptech should read "Smoke Screen" (one of numerous investigative books on the subject), and s/he should also have a look here. Great that Dr. Oreskes is in Australia. Wish that I could see her talk in person.
  10. How significance tests are misused in climate science
    56.KR "any uncertainty invalidates human driven global warming" That seems like the extreme end of a spectrum of opinion that starts somewhere near "some uncertainty may question the magnitude of human driven global warming". This may in fact might be where the IPCC sits. I'm happy to agree that the example you highlight is wrong but I don't see that invalidates the whole spectrum. I actually don't know were I sit on that spectrum it probably changes on a daily basis maybe something like "there is sufficient uncertainty that we cannot accurately attribute warming." Anyway I think there are a couple of statements in your post that come out of the false dicotomy of denier/alarmist. They are products of the politics rather than the science. For me this is a barrier for resolving the issue. If Judith Curry can step outside of the consensus to ask questions only to be labelled incompetent or a dupe or worse then I don't think there is much hope for the process. I really don't need to be convinced that the Marshall Institute is wrong, i need to see that Curry asking questions is accepted as part of the normal scientific process. those statements were "But given a pile of reasons on one side of an argument and a pile of illogic, poor data, or contradictions on the other, you can generally make that call. If not, study some more." and "Small uncertainties (part of the nature of science and inductive reasoning) do not unseat an entire block of science - especially when the alternatives presented are hugely more uncertain." It strikes me that "AGW v's the rest of the world" is more Hollywood than science. (anyway sorry this is drifting away from stats)
  11. Naomi Oreskes' Merchants of Doubt Australian tour
    It is indeed silly. It would be laugh-out-loud silly if not for decades of now well-documented tobacco-funded research dedicated to finding ways of creating stronger addiction to the product. My dad died of oat-cell cancer last year (97% of those who have oat-cell cancer are or were smokers). I'm not quite ready to laugh at the ethical squirming of Big Tobacco and its misguided defenders. On Nierenberg, see Mr. Rabett.
  12. Climategate a year later
    We mustn’t forget all that fuss about Dr. Rajendra Pachauri, chairman of the Intergovernmental Panel on Climate Change (IPCC) either. He was eventually revealed to be “a scrupulously honest man”. http://www.monbiot.com/archives/2010/08/26/the-smearing-of-an-innocent-man/#more-1281
  13. Naomi Oreskes' Merchants of Doubt Australian tour
    #64: "evidence ... where is the research" Consultancy agreements 1986 I spoke with Fred Seitz about renewing his and Mac McCarty's consultancy agreements for six months to the end of this calendar year. I said to Dr. Seitz that we would review our entire arrangement at that time and based upon the direction in which our medical research program is going. This is silly and wildly off topic.
  14. Climategate CRU emails suggest conspiracy
    Since the rebuttal for climategate addresses the cynicism of the skeptics towards climate science another good rebuttal should debunk the argument "climate scientists exaggerate to get more funding". I know this defies the comments policy, but I see this argument everywhere in skeptic blogs and conservative op-eds. I would really like to see this argument get shot down. Do you think a rebuttal for this argument would be a good idea for Skeptical Science?
  15. Are ice sheet losses overestimated?
    John Kehr, I know that the Gisp2 graph showing of an individual year is completely irrelevant. My exact words were: "You can pick a core or two out as much as you want, but unless you are able to give some sort of comparison to current temperatures then its irrelevant. I could take your GISP2 core and do this: http://www.skepticalscience.com/pics/Gisp2Graphedited.png but that doesn't make it right. Showing half the evidence doesn't either... " The orbital forcing is overall cooling in the Northern Hemisphere as is evident in Kaufmann et al. 2009 and in Ruddimann 2006. I will respond to the rest in a minute
  16. Naomi Oreskes' Merchants of Doubt Australian tour
    #61:"accusations are that Dr. Seitz oversaw research funded by R.J. Reynolds that questioned the link between tobacco and cancer." Wow, Poptech using exactly the same 'deny the evidence', 'make it appear there's controversy' tactics pioneered by Seitz and Co. Read RJR's words and weep: Presently, there is a good deal of controversy in the scientific sector on the subject of smoking and health, with prominent medical authorities lining up on each side of the .... arguments. ... For every charge that has been made against cigarettes, there has emerged a strong body of scientific data or opinion in defense of the product. In evaluating and monitoring the special projects that we fund -- particularly the sole-sponsorship programs -- R.J. Reynolds Industries has secured the services of a permanent consultant -- Dr. Frederick Seitz, former president of Rockefeller University. Dr. Seitz is with us today and has agreed to describe these various R-J-R sponsored programs for you. So the RJR position is that there's controversy, a strong body of scientific evidence in their defense, and who is brought in to describe their funded research?
  17. Naomi Oreskes' Merchants of Doubt Australian tour
    Poptech. I find it amusing that you refuse to count "think tank reports" as scientific literature, when given a new report from the heartland institute (for example) the so-called sceptics are keen to elevate that material as of equal standing to peer reviewed scientific publications.
  18. The science isn't settled
    Eric - there is a relevant discussion on another thread, starting here (claim of certainty) and here (thoughts on induction in science).
  19. Naomi Oreskes' Merchants of Doubt Australian tour
    Poptech - Several courts of law (and congressional investigations) found that the 'science' pushed by Singer, Seitz, and others was fraudulent and deceptive, to the tune of a rather huge settlement with the tobacco companies. Please see the linked documents here, most are part of the legal case. Given the $$$/time spent on those court cases, I'm inclined to agree with the conclusions of the courts. Either they were deceived by their sponsors, unable to properly perform the science, or they intentionally lied for some reason. I don't know, I cannot determine their motivations - take your pick. [Moderator - I realize I'm stating that someone may have been deceptive; please note I'm only pointing out conclusions from several law cases, which have by legal judgement been established as conclusively true]
  20. The science isn't settled
    Tom, classical mechanics is 100% certain within a frame of reference in which the evidence (measurements) are 100% consistent with the theory. As string theory evolves along with empirical measurement techniques, it will be validated or invalidated, e.g. http://www.newscientist.com/article/dn11085-new-particle-accelerator-could-rule-out-string-theory.html Theories that are yet to be grounded or validated in any way are notions, but string theory is grounded since it already reconciles quantum mechanics and relativity. It lacks sufficient technology to be validated by a high energy particle predicted by the theory. Obviously such an area, far outside my expertise and classical intuition, is easy prey for a falsely subjective interpretation. As BP points out in another thread, the theory or hypothesis is correct or not and statistics are suitable for noisy measurements. There is no such thing as a noisy theory, noisy conceptual framework or noisy science.
  21. How significance tests are misused in climate science
    Berényi - Thank you, those are some very interesting papers. I'm a bit concerned that the Joshi et al 1999 only seems to study 90 days of data. We know "weather" is chaotic; climate doesn't seem to show the same fractal nature of variation, and 90 days of data can only support cyclic variations of 30-45 days at most, not millenia. Extending that analysis to thousands of years will take a great deal more data. The CO2 paper states that: "Therefore the long-range correlations in the atmospheric CO2 that deduced from the present analysis can help in recognition of anthropogenically induced changes caused by increased CO2 emissions to the atmosphere on the background of natural atmosphere changes. So they appear to be identifying patterns of variation that be identified superimposed on anthropogenic CO2 change to better identify the signature, and don't seem to make any claims about low frequency (long term) variation coming from "pink noise". Finally, the cloud cover/fractal distribution paper is excellent. That's a very clean analysis of fractal dimensionality. But I don't see the connection between fractal self-similarity and 1/f noise. Nor do I see the significance with regard to tracking climate changes. I really don't see how these descriptions of weather are critical issues for climate. Parametric descriptions of fractal systems are perfectly adequate for analyzing mass behavior, as long as the parametric description includes observed internal variability at the appropriate scales.
  22. Naomi Oreskes' Merchants of Doubt Australian tour
    Poptech #55 Not a terribly convincing argument from you. Typical so-called-sceptic approach of taking a position, emphasising a very small part of the argument (without examining the validity of the argument in the broader context) and then using that to generalise to the whole argument without justifying your case properly. This is essentially the technique of claiming that scientists are deliberately misleading while simultaneously constructing arguments designed to mislead yourself. As DSL says, rhetorically fascinating.
  23. Naomi Oreskes' Merchants of Doubt Australian tour
    That Marshall Institute document is rhetorically fascinating, Poptech. Immediately after pointing out that corporations are ethically bound to do the right thing and that good people just do not do those kinds of things, even when they can make a great deal of money from it, the document then says this: Is all privately-funded research tainted? Is public funding the only “clean” source of support for scientists? Seitz saw a critical role for private funding (through companies and foundations) and saw dangers in science becoming too dependent on either private or public support. (emphasis mine) Those are interesting recognitions of interference for an institute dedicated to decidedly conservative (economic and military) agenda. The last bit is just bizarre, given the initial warnings. What should science be "dependent on"? Backyard scientists? Or is the implication that it should be a 50-50 split between corporate and government money? Who should I trust for my climate science: government-supported scientists or corporation-funded scientists?
  24. Naomi Oreskes' Merchants of Doubt Australian tour
    Poptech: Please explain what's wrong with her argument. The Marshall Institute PDF you linked to confuses personality with science, and ignores/misrepresents the USDoJ's successful prosecution of the tobacco industry under racketeering laws.
  25. How significance tests are misused in climate science
    HumanityRules - The reason this is an important point is due to the oft-repeated claims by various people that summarize to "any uncertainty invalidates human driven global warming", or at least needs "sound science", a favorite claim of the Marshall Institute, for example. There is always some level of uncertainty in science, some small chance that your theory doesn't actually match up with the behavior of the universe. Perhaps you need better measurements (Newtonian vs. Einstein's physics, for example) to point it out. Perhaps your epicycles are way too complicated. Perhaps you have been deceived by ideology, or bad choice of drugs! But agreement with known physics and statistical evaluation of the data (whether Bayesian or frequentist) helps you to rank hypotheses in order of agreement with the data. That's key to making a scientific judgement. Yep, it's somewhat subjective. All induction is. But given a pile of reasons on one side of an argument and a pile of illogic, poor data, or contradictions on the other, you can generally make that call. If not, study some more. Yes, there is some possible uncertainty even in the law of gravity - it might stop working tomorrow. Nature may be manipulated by the lawn gnome Illuminati. Climate science may be the result of a cabal of One World Socialists bent on world domination. Or the centuries of scientific research and independent investigators may have identified key elements of how we affect climate by our actions. We can rank the uncertainties - only the last is even remotely a probable (first and second definitions) hypothesis. Small uncertainties (part of the nature of science and inductive reasoning) do not unseat an entire block of science - especially when the alternatives presented are hugely more uncertain.
  26. Berényi Péter at 12:23 PM on 17 November 2010
    How significance tests are misused in climate science
    #51 KR at 05:17 AM on 17 November, 2010 You state that weather is in a state of Self Organized Criticality - SOC. I have been unable to find any references that indicate this; do you have a paper to link to on this subject? There's a review paper. XE: Extreme Events workshop Developing a Research Agenda for the 21st Century Boulder, Colorado, on June 7-9, 2000 Self-Organised Criticality and the Atmospheric Sciences: selected review, new findings and future directions Suraje Dessai & Martin E. Walter "We suspect theories of complexity, such as SOC, have been underrepresented in the atmospheric sciences because of their "soft science" character. Atmospheric sciences have historically developed from centuries of advancement in the hard sciences, such as physics, mathematics and chemistry, etc. It would have been unlikely to see a quick transition from the classical reductionist and reproducible science approach towards an abstract, holistic and probabilistic complex science. Proof of this is the fact that only a small number of scientists have cited the few applications of these theories in the atmospheric sciences." "Another possibility for the neglect of SOC in the atmospheric sciences is the increased funding of applied atmospheric sciences (e.g. climate change research) vis-à-vis the decreased funding of "basic" research, i.e., according to Byerley (1995) research to increase knowledge; to answer a scientific as opposed to a practical question." This one has some ideas of its own: Fractals, Vol. 7, No. 4 (1999) 421­425 IDENTIFICATION OF SELF-ORGANIZED CRITICALITY IN ATMOSPHERIC LOW FREQUENCY VARIABILITY R. R. JOSHI and A. M. SELVAM This is also interesting (possible scale free behavior of atmospheric flows from 1 cm to 1000 km). Science 9 April 1982 Vol. 216 no. 4542 pp. 185-187 DOI: 10.1126/science.216.4542.185 Area-Perimeter Relation for Rain and Cloud Areas S. LOVEJOY Or this one on 1/f noise in a particular time series. Atmos. Chem. Phys., 7, 629­634, 2007 Technical Note: Long-term memory effect in the atmospheric CO2 concentration at Mauna Loa C. Varotsos, M.-N. Assimakopoulos & M. Efstathiou
  27. Naomi Oreskes' Merchants of Doubt Australian tour
    Poptech, I have some relevant personal information on this subject. My brother was, for a number of years, one of the public faces of a major tobacco company. His job was to deny the connection between second hand smoke and cancer. He gave me a copy of Thank You for Smoking shortly after he started, telling me that "This is me. This is my job." To deny, confuse, obscure, delay, and otherwise block the science and political action resulting from it. To make s**t up. The science of tobacco and cancer is quite clear; I don't know why Dr. Seitz, Fred Singer, and others pushed the tobacco side of things, but ideological reasons seem to match their behavior. They certainly weren't doing good science in claiming tobacco was harmless. And they weren't operating in their fields of expertise - physics knowledge != biological knowledge.
  28. The Inconvenient Skeptic at 11:44 AM on 17 November 2010
    Are ice sheet losses overestimated?
    @Robert, I appreciate that you recognize the relevance of the MWP in this particular discussion. I promise to stay strictly on Greenland with regards to the MWP. I will take issue with your statement that: "What the mass loss for Greenland "should be" is completely irrelevant." Let us start on what we should be able to agree upon. The ice loss during the MWP was of a comparable magnitude to what is currently happening. We should also agree that the MWP in Greenland was a natural occurrence. That leaves us with a situation in the recent past that naturally had comparable ice loss to the current day. This leaves open the possibility that the current warming is natural in cause. This is partially why I am curious about the behavior of the ice sheets during the 1940-1950 period. Many NH glaciers experienced significant retreat during this period. That makes understanding the natural sheet loss very relevant. If the sheet loss was as great in 1940, then it is very hard to say that CO2 emissions have caused an "unnatural" rate of loss today. Comparing to the GISP2 would require a comparable smoothing as to what the ice core had. Since most ice cores are heavily smoothed showing a single year is meaningless. A more comparable one would be GRIP which runs until 1989. That is close to the 1990 point you have on the smoothed GISP2. Certainly there is no sudden increase evident in the GRIP data. Since this is much closer to single year data it is a better comparison to the single point compared to the GISP2 you linked. (many will be amused by that from long discussions on my site) The GRIP data shows that the 1930-1940 period were very warm. That is why the sheet loss from that period is relevant. I argue that it could easily have been of comparable magnitude to the current ice loss. If that is the case then CO2 levels have had little impact. I hope that you recognize that I am not just arguing for the sake of arguing. My own analysis of the data indicates that there is reason to believe that the current warming is natural. I would also note that the orbital forcing is cooling summers and warming winters. They do go hand in hand. John Kehr The Inconvenient Skeptic
  29. Are ice sheet losses overestimated?
    Chris G, It is possible that the crust is still feeling the effects from previous iceloads. There is always a delay in these sort of mechanisms. Maybe 400 years from now it might start to rbound. Who knows...
  30. Naomi Oreskes' Merchants of Doubt Australian tour
    Poptech #47 Indeed, very funny. Check the link to the audio in the main article for a demolition of the critique.
  31. Naomi Oreskes' Merchants of Doubt Australian tour
    Re: Poptech (47) Good one. Those who say you don't have a sense of humor are now corrected. The Yooper
  32. Are ice sheet losses overestimated?
    Re: Chris G (22) Apologies are in order. You and Robert Way are correct. In my defense, I had just done a long series on another website on Jason/Topex/Poseideon and ICESAT and still had that in the brain's RAM. Didn't help that I was commenting from the cellphone & had no access to the correct info. Sorry for the confusion. Moral of the story: memory is no replacement for actually looking stuff up. The Yoooper
  33. How significance tests are misused in climate science
    51.KR 52 Tom 53 Dikran The specifics of SOC aside, I'm not sure where your difference with BP lies, it appears to be one of emphasis. The uncertainty for BP is crucial for the others it's a minor irritation. Specifcally to KR on your point 2. Skeptics seem to believe that the introduction of the IPCC into climate science has caused some leap-frogging in that process you describe in order to get all the way to CAGW and to provide the basis on which policy can be formulated. I'm not sure anybody expects perfection but recognition of the imperfection would be useful start. As an example I was browsing thru Maarten's department website. There's plenty on clouds and the suggestion that we haven't even got the measurements right yet. It becomes a matter of (expert) opinion as to whether that constitutes certainty or uncertainty. Dikran you seem to introduce an element of the subjective into the discussion. The gambler (or us) can judge the hypothesis based on our "belief", we could replace that word with experience or expert opinion. In fact the example you give of 6 heads in a row could very easily lead us down the wrong path. I could point out the chances of that are ~1%, suggest you're trying to cheat me and if this was the Wild West shoot you. That might be evidence of my poor gambling experience (or violent tendancies). The stats in this case have done nothing to bring us to this conclusion it's actually all down to opinion, in fact my poor use of the stats might have contributed to giving me certainty about my wrong decision. As Maarten points out stats don't point us to which is the correct path to take. As I'm ignorant on this subject to what extent do stats rely on subjective judgement? I'd always thought the point of them was to get away from this but from the descriptions I'm reading here at some level subjectivity seems to be part of the process. In Bayesian the attempt is to build it into the process. In frequentist (as in the example in #49) in seems to be added afterwards.
  34. Climate cherry pickers: cooling oceans
    kdkd Well it was a good 'orse - took all 13 of the others to beat it...
  35. Are ice sheet losses overestimated?
    Thanks Robert, I'd assumed an upward movement since we are talking about a loss of mass above, at least overall, though not necessarily in the interior of Greenland. On another read, I see that you did say, "downward mantle motions". That's very interesting; have to study that one a while. Hard to imagine why the mantle would be moving downward in the interior. Downward relative to the exterior of the ice sheet, which is loosing more mass, sure, but relative to the surface in general...puzzling.
  36. Are ice sheet losses overestimated?
    Chris G, I guess it is partially my fault with the explanation. Crustal movements are not only upwards. They can be downwards too. So what was modeled was that part of the downwards mass trend in the center of Greenland was due to the crust sinking under the weight of ice... So without the downward mantle motions, you would assume that the reduction in gravitational pull on the grace satellites would be due to ice loss. Wu et al. 2010 hypothesize/model that it is in fact due to a downward crustal motion.
  37. Are ice sheet losses overestimated?
    Broken link; should be GRACE.
  38. Animals and plants can adapt
    CBDunkerson, if you can tell me how reducing CO2 emissions can help reforesting the destroyed rainforests all over the world and help to regain the lost top soils (destroyed due to monoculture farming) and regain the lost wildlife habitats destroyed in the process I would like to believe you.
  39. Are ice sheet losses overestimated?
    John Kerr, Another way to approach this question is that the maximum amplitude in sea level change from the MWP potential maximum (21 cm greater than present) to the LIA potential minimum (26 cm lower) is 47 cm and can be as small as 31 cm over the last 2000 years (Grinsted et al 2010). The expected sea level rise according to Grinsted et al (2010) if there is NO additional warming (this doesn't include 2010s warm year) is between 21 to 44 cm by 2100. So not even including any additional warming we see, we will sea a sea level rise which is as great as the amplitude between the highest of the MWP and the lowest of the LIA by 2100. Kinda supercedes your natural variability theory doesn't it? Lets dive a little deeper. You may not be a glaciologist but i'm sure you have heard about dynamical ice changes which are underway in Greenland and West Antarctica correct? These ice changes are irreversible in West Antarctica (particularly in Pine Island Bay) where the bed slopes downward into the interior of West Antarctica. The losses from this region ARE accelerating, the same as they are from portions of Greenland grounded below sea level. The mechanisms are WELL-UNDERSTOOD and continued oceanic and atmospheric warming will hasten the removal of buttressing ice shelves/grounding lines and thereby accelerate flow into the oceans. But back to your initial premise. It is true that climate throughout the holocene has been to some degree variable. And it is true that the timing of the hypsithermal is different in different regions thereby causing periods of warming in the past. But since the Hypsithermal you DO NOT see spikes in sea level of 2 meters. You see *relative* stability. Oscillating climate patterns superimposed on a downward orbital signal. You can pick a core or two out as much as you want, but unless you are able to give some sort of comparison to current temperatures then its irrelevant. I could take your GISP2 core and do this: http://www.skepticalscience.com/pics/Gisp2Graphedited.png but that doesn't make it right. Showing half the evidence doesn't either... Finally, Nowhere in the article does it talk about AGW. We don't use ice losses to diagnose and attribute AGW. We use empirical evidence from a multitude of places. Just because ice losses are able to detect associations with warmth does NOT mean that we are saying this is how we PROVE it is man-made.
  40. Are ice sheet losses overestimated?
    Daniel (#15), Hmm, maybe, but your understanding of GRACE is a little different from mine. I was under the impression that the primary measurement taken by the satellites was the distance between them rather than the altitude above the surface. Differences in the distance between the satellites is primarily caused by the lead of the pair accelerating into an area of more mass and 'decelerating' as it leaves the area, and the same for the other in the pair. As far as I can tell, altimetry has little to do with it. I'm sure a mountain range affects GRACE, but I'm not sure how it would distinguish between a mountain range and a large deposit of iron ore near the surface. It is affected by local variations in mass.
  41. Climate cherry pickers: cooling oceans
    KL #37 "kdkd makes an interesting point. Clearly we have to try and pick winners here. Sort which data is crap and which might be close to correct. When there is conflicting data - the method is to look at its nature and try to find logical reasons why one might be good enough to be useful and the other not so." Indeed I do. Concentrating on the lame horses (with good genes) at the back of the field instead of the front-runners seems to be a strange way to pick winners. Or in other words, the lack of precision of the OHC and TSI measures do not falsify the other strong coherent evidence for anthropogenic global warming.
  42. It's the ocean
    #17: "As the earth's crust is thinnest below oceans this may heat the water above." Not by much. Here's what Douglass and Knox 2009 have to say about tectonic heating: The geothermal contribution is constant [certainly over human time scales], but cannot be ignored because it contributes directly. The flux into the ocean and trenches averages 101 ± 2.2 mW/m2 and that into the land and shelves averages 65 ± 1.6 mW/m2 (globally averaged, 87 ± 2.0 mW/m2) --emphasis added Compare to solar heat flux, same source: The mean solar flux S0 at the earth’s orbit is assumed to be 340 W/m2±1 W/m2 A sizable difference in favor of solar heat.
  43. Are ice sheet losses overestimated?
    John Kerr, What the mass loss for Greenland "should be" is completely irrelevant. We are not arguing that the Greenland Ice Sheet should be stable or should be in a state of continual mass balance. What you are ignoring is that the current trends from Greenland show a distinct acceleration that is far greater than what was predicted by the IPCC. Estimates of Greenland's ice losses fit an exponential curve better than a simple linear estimate. This suggests a destabilization process is occurring. If you would like to talk about the MWP and Greenland losing ice, it is pretty well understood that sea level was likely higher during the MWP. Grinsted et al. (2010) show that sea level over the past 2000 years reached its maximum around 1150 AD at around 12–21 cm greater than present. This number is much smaller than the predicted range of 0.9 to 2m (Rahmstorf 2010) that is expected by the end of the 21st century. The reason the MWP was able to have a higher sea level compared to today is because it lasted for a long time thereby allowing for the Greenland Ice Sheet to continually contribute to sea level rise. Furthermore, because of the length of the warm period the thermal inertia of the oceans was fully fulfilled. It should be noted that Grinsted et al (2010) find that if there is no further warming (from 2009 onwards) that sea levels will still surface the MWP by up to 20 cm from the MWP maximum (remember, no additional warming).
  44. Naomi Oreskes' Merchants of Doubt Australian tour
    JohnHarrington: There's another, very simple, explanation - the possibility that the woman you were talking to is incompetent, and has chosen to blame circumstances and other people rather than face up to the reality. I'd say that it's far more likely than the entire field of archeology being corrupt and incompetent. Also ... archeology is far more subjective than physical sciences like atmospheric chemistry, etc. We're unlikely to ever know just when or how the horse was domesticated, but we know for certain that CO2 absorbs long-wave IR.
  45. It's the ocean
    h-j-m #17 But more evaporation equates to more water vapour in the atmosphere (aka latent heat) which will result in warming the atmosphere. This is incorrect, I believe. The amount of water vapour that the atmosphere can hold is determined only by the temperature of the atmosphere. Factors that increase only the rate of evaporation will simply increase the rate of condensation out as well. In the atmosphere that means clouds form faster and then more precipitation. 1. Marine as any other life needs energy to build its biomass. By now we are next to successful clearing our oceans of it. In consequence that energy is not used for this purpose and heats the water instead. I would think the main route for marine life to obtain energy is photosynthesis and respiration. Indeed, given biochemistry, I would expect respiration inside marine animals to keep them at a higher temperature than the water (blubber in marine mammals would seem to corroborate this). Therefore I think denuding the oceans would most likely have a nett cooling effect. 2. There may be spots where the earth crust has grown thinner over time and therefore more of the earth's interior heat gets transferred to upper layers. As the earth's crust is thinnest below oceans this may heat the water above. This is beyond my realm of expertise, but I would note that what is actually required is a nett thinning of the crust for the oceans to get warmer. "some spots" is not, of course, sufficient. 3. Not only are we clearing out next to all marine life from the oceans we are using them as garbage bins as well. I recall reports stating that all over the oceans probes were taken that revealed a higher content of plastics than phytoplankton. I think it is rather likely that these areas when hit by visible light will absorb more of it and in return emit more infrared radiation aka heat. Phytoplankton photosynthesize (by definition) which is the absorption of visible light, I would imagine they are better at it than plastic, unless perhaps most of the plastic is black ...
  46. Are ice sheet losses overestimated?
    Whoops, Berger and Loutre is of course 2002, not 2009.
  47. Are ice sheet losses overestimated?
    TIS - "supposed to be" has with it - "expectation from a particular model". Which model do mean? Real world climate models that consider all forcings would say that Greenland should be losing mass because northern temperatures are rising and sea warming. I assume you mean fantasy models where you explain climate without the need for GHG and ice-ages can be explained by milankovitch forcings and albedo alone? Well milankovitch forcings are declining which suggests Greenland should be gaining ice (and maybe should have over last 6000 years), but of course that change in forcing is insignificant compared to GHG forcings. For a more realistic view, A. Berger and M. F. Loutre, 2009 argue for a very long inter-glacial.
  48. Dikran Marsupial at 06:56 AM on 17 November 2010
    How significance tests are misused in climate science
    I'm happy to third KRs comment. It is staightforward to show that it is reasonable to talk of the probability that a hypothesis is true. If BP and I were to bet on the number of times a coin I took from my pocket came up heads and I flipped six heads in a row, then BP might well hypothesize that my coin was biased. However, no matter how many times I got a head one after another, he could never know for certain that the hypothesis were true, as (infinitely) long runs of heads are possible, just (infinitely) improbable. But does that mean he is limited to saying "I don't know" when asked if his hypothesis is true? Of course not, most people would have no difficulty in quantifying their belief in the truth of BPs hypothesis. Indeed that is exactly what gamblers do whenever they make a wager, which IIRC is where the Bayesian approach to probability (a mathematical framework for quantifying belief in the truth of an uncertain proposition) originated. BTW - as I belive Donald Rumsfeld (sort of) said - there are things you know, there are things you know you don't know and there are things you don't know you don't know. Statistics of any framework is a good way to deal with the things you know. Bayesian statistics also has a good way of dealing with what you know you don't know - you introduce a minimally informative prior (using techniques like MaxEnt and transformation groups to decide what is minimally informative) representing your ignorance of that element of the analysis and integrate it out (Marginalisation). The things we don't know we don't know, we can't do too much about, other than adopting a cautious approach, avoiding overstatement of our findings and being willing to recognise when we are wrong.
  49. Animals and plants can adapt
    h-j-m wrote: "Reducing CO2 emissions (unless they stem from deforestation) will not help a bit." CO2 emissions are causing global warming, which is causing habit loss for species all over the planet. Thus, reducing CO2 emissions definitely would help, and more than 'a bit'. Also: "Therefore I completely fail to see how rising temperatures may cause general losses in biodiversity." Which is happening faster, climate change or the evolution of new species? That is, unless you think that evolution happens over the course of a few decades, it should be entirely obvious that 'warmer = more biodiversity' is an invalid assumption. Species which cannot adapt to the warmer conditions will become extinct and new species will not evolve at the same rate... ergo declining biodiversity.
  50. The Inconvenient Skeptic at 06:43 AM on 17 November 2010
    Are ice sheet losses overestimated?
    @ Yooper, Where is the source for your data? 0.0 +/- 0.5 °C for the past 10,000 years? Seriously... Vostok, Taylor Dome Not arguing the error of Rohling, but the data shows significant variation, you would have to assume the error ALWAYS went towards no variation to not get a few meters of variation. Also, you avoided my question. What is the mass loss of Greenland supposed to be? I can be specific. What should the mass loss be for Greenland in an interglacial at the current state? Should the mass loss be zero? Should it be increasing or decreasing?

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