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  • Hockey sticks: Round 27 « RealClimate
    I posted this question earlier moderator Yes you did It was eliminated on the basis of our comment policy see our discussion of signal vs noise Postings which seek to muddy the issues rather than clarify them are often eliminated especially when the tone seems inappropriate This comment was screened in to make a point See below There are 4 NH temperature actual measurements records which go back at least 200 years i e Eastern US Sweden Central England and Armagh Observatory moderator This is just wrong There are 9 that go back to 1777 4 that go back to 1753 There are many reviews of the data by Jones Bradley and others Please aquaint yourself with the facts before posting Sometimes we will correct factual errors in comments sometimes we will simply screen out the comments altogether if the net effect is to disinform our readers as we don t have the time to correct every fallacy None of these records exhibit any behaviour remotely similar to the hockey stick shape moderator This too is just wrong In fact the available instrumental temperature records when formed into a hemispheric mean closely match the reconstructions See the review paper on Climate Over Past Millennia by Jones and Mann 2004 figures 2 and 3 In fact it is clear that the instrumental estimates run a bit warm relative to all of the proxy reconstructions i e they suggest even less of a little ice age in the 18th and 19th centuries This is likely due to problems with thermometer sun exposure which is particularly pronounced during the summer at high latitudes prior to the modern introduction of Stevenson screens There is much literature on this You can start out with the review paper cited Don t you think this is strange moderator What appears strange actually is your willingness to post a comment without familiarizing yourself with the basic facts first In the future please make sure to familiarize yourself with facts before posting here Thankyou 24 Stephen Berg says 26 Oct 2005 at 11 59 AM More evidence of climate warming MAJOR CORAL BLEACHING EVENT EXPANDS ACROSS CARIBBEAN SEVERE IN PUERTO RICO AND U S VIRGIN ISLANDS NOAA s New Coral Reef Watch Satellite Bleaching Alerts Aiding Managers http www noaanews noaa gov stories2005 s2526 htm 25 greg meyerson says 26 Oct 2005 at 12 16 PM thanks eli I need to know something about the difference between arithmetic and geometric mean I ll ask a math friend but if you want to help me I m at meyerson att net I actually get the point about square roots I think Arithmetic mean avg 1 n x1 x2 xn Geometric avg x1 x2 xn 1 n where is to the power of William 26 Lynn Vincentnathan says 26 Oct 2005 at 12 24 PM Re 8 let me clarify the difference between scientists and environmentalists I assure you the hosts of this site are definitely scientists though I heard of a Chicago scientist buying a SunFrost frig 1 10 the electricity of other frigs so some might also be environmentalists in their private lives SCIENTISTS follow THE SCIENTIFIC MODEL of avoiding false positives making a claim when it is false that is they do not make claims unless there is high confidence that they are right usually 95 certainty so as to protect their reputations otherwise no one will believe them again like the boy who called wolf ENVIRONMENTALISTS those concerned about reducing harm to people and the earth follow THE MEDICAL MODEL of avoiding false negatives acting as if there is no problem when indeed there is that is they do not need high certainty of a problem to start addressing it It s unimaginable for a doctor to tell a patient that there is only 94 certainty that the lump is cancerous so they won t operate Some environmentalists even follow the precautionary principle of disallowing actions unless they are proven safe like not emitting GHGs beyond needs and simple pleasures unless we are 99 certain AGW is not happening the higher level of certainty is due to the risks being so grave I m an environmentalist I already figured AGW was happening back in 1990 5 years before it reached 95 scientific certainty in 1995 as did Pope John Paul II who told us it is everyone s responsibility to solve and I started reducing my GHGs in cost effective ways and am saving hundreds per year without lowering my living standard Since evidence of GW has continued to pour in and become stronger stronger and since I m saving heaps of money by abating it I don t think any contrarian or scientist can convince me to start emitting more GHGs even if it becomes 100 certain AGW is not happening The HOCKEY STICK was a done deal for me back in 1990 well before the first articles came out on it Regular GW is no longer my greatest concern I m on to worrying about RUNAWAY GW or the VENUS EFFECT our human induced warming causing nature to start emitting more more GHGs CO2 CH4 in positive feedback fashion perhaps leading to near extinction of life on earth as happened from GW during the end Permian extinction and the other 4 great extinctions I m convinced we re already into or on the brink of the 6TH MASS EXTINCTION though we may not reach scientific certainty until itâ s a done deal Itâ s possible we may not be able to reverse this even with big GHG cuts but I have to keep doing my best with the hope it s not too late and would keep doing my best even if scientists finally do tell me it s too late hoping they re wrong That s what it means to be an environmentalist or Christian or Buddhist etc 27 Tom Fiddaman says 26 Oct 2005 at 8 27 PM Re 26 8 was hardly deserving of an answer but I d draw a different distinction Science is about figuring out how things work and the usual test of understanding and usefulness is prediction Success at prediction is enhanced by maximizing the number of different hypotheses models you can generate and test against numerical data and other available information 95 confidence levels and the like are used as a sieve to reject the bad models but that doesn t mean there s a 95 chance of being right The curse of course is that 5 of the time you re wrong randomly and those results are disproportionately interesting and thus likelier to be published However time eventually resolves such problems by providing more data to test out of sample predictive capability It would be great if there were some way to update the proxies and test temperature reconstructions that would really lay to rest or not all the accusations of spurious correlation etc Environmentalism on the other hand is more about values do you care if polar bears go extinct Do you prefer the mall or the forest etc Science and environmentalism may get intertwined if for example you prefer the mall but predict that environmental side effects might compromise the ability of industrial society to build more of them I see no real problem if many scientists are also environmentalists If they were systematically biasing their own results through wishful thinking or more sinister means a lot more of GW theory would have been refuted in the last 15 years As an aside SunFrosts are perhaps 1 10 the energy of a lousy old fridge or perhaps a big commercial fridge but the best ordinary top freezer consumer fridges are now very good a SunFrost might use 2 3 the energy It s rather striking to me how many people will buy a 6000 SubZero or Northland of dubious efficiency without batting an eye and how few will shell out less than half that for a SunFrost Shows how far we are from actually confronting the issue 28 John S says 26 Oct 2005 at 8 37 PM Lynn Not wanting to rain on your doom and gloom But surely the fact that there is still life on earth despite previous huge changes in our atmospheric composition suggests that the Venus effect is a bad science fiction scenario rather than a serious possibility Indeed let s just suppose that we wipe ourselves out with an event of similar magnitude to the end Permian extinction In your apocalyptic scenario that removes the cause of the atmospheric imbalance and the earth can go back to some more hospitable equilibrium no The fact that the earth has been capable of sustaining life for the past billion or so years suggests to me that you might be worrying a little too much 29 Dano says 26 Oct 2005 at 11 50 PM But surely the fact that there is still life on earth despite previous huge changes in our atmospheric composition suggests that the Venus effect is a bad science fiction scenario rather than a serious possibility I m not really taking sides here but pointing out that for the underlying support of the don t worry argumentation here to be effective IMHO the premise must be that the previous 5 extinctions were caused by sentient beings that knew and debated the consequences of their actions thus everything turned out OK cause there s still sentient beings around to choose their fate My sniff test for this argument causes my head to jerk back and my nose to scrunch up Anyway the post topic was about Hockey Sticks and debating attribution and the comments got around to noticing that debating consequences is more fruitful than attribution I agree Fer chrissake getting bogged down in the attribution is a subset of the larger debate on action Let us keep that in mind when we calculate our personal energy expenditures Best D 30 garhane says 27 Oct 2005 at 3 33 AM I would like to extend congratulations from a general reader who has followed this blog and the evolution of climate science for a few years The success of the Real Climate group in the brief life of the blog has been steady and swift Now the blog has become authoritive while it continues to offer an absolutely fascinating and truly educational read delivered with style One pictures the coach full of the members of the Pickwick Club careening down the road towards a noisy dinner with lots of good talk afterward And now here is the Wall Street Journal giving prominence to two more supporting accounts in the historical review of climate summed up figuratively by the Hockey Stick And is that the dean of the lot von Storch offering what looks like a substantial climb down from a rather rude comment only a year ago And who do we see behind the parade carrying broom and dustpan Can it be Don Quixote McKitrick and Sancho McIntyre Clearly the burden of the work has not proven excessive so I hope one can look forward to a lot more of the same education in science the general reader receives from the scholars who contribute to Real Climate Even those who oppose you have enriched the blog and it just does get any better than that 31 Ferdinand Engelbeen says 27 Oct 2005 at 3 35 AM Re 20 Steve if the laws of thermodynamics still hold then a net extra loss of 3 W m2 top of atmosphere should give more cooling or less warming dependent of the absolute values In the same period the direct increase of GHGs has given some 0 7 W m2 more heat retention at the surface The difference may be a result of observed faster air circulation over the tropics The more recent papers touch on related topics but it is not clear to me yet where the differences are as e g the last paper substracts signals of different satellites while the first uses only one signal Need a few days more to find it out 32 Robert Simmon says 27 Oct 2005 at 9 03 AM re 13 Some intro level global climate change articles which I will shamelessly recommend to you from the NASA Earth Observatory a site I contribute to Global Warming primer on anthropgenic warming Will Runaway Water Warm the World Arbiters of Energy discussions of the Iris effect and water vapor feedbacks Under a Variable Sun solar forcing Tango in the Atmosphere Ozone and Climate Change self explanatory 33 greg meyerson says 27 Oct 2005 at 10 54 AM The arithmetic mean or average of a group of n numbers is just their sum divided by n So the arithmetic mean of 6 10 and 23 is 39 3 13 The geometric mean of a group of n numbers is the nth root of the product of those numbers So the geometric mean of 5 45 and 120 is the cube root of 5â 45â 120 or 30 hi william I got the above answer to my question about arithmetic and geometric means equivalent to yours but you have to admit the above is a lot simpler for dummies aka most of the population 39 3 13 sum of x1 x2 xn 1 n best imo is using both types of examples as I mentioned I am an english professor critical theory am lit and advanced comp teaching at an hbcu historically black college or univ I am teaching a comp course where all our readings are on global warming this course has to educate and I purposely picked subject matter on which I am pretty much like they are though with better research habits most of them are afraid of science and know little math I suspect the american population isn t much different this issue like many others is too important to be left to the experts and too important for the experts to be left out so the experts have an enormous responsibility especially given the declining state of science ed and ed in general in public schools but also given the disciplinary division of labor don t you guys want at some point students from high schools and universities to be able to ask questions of the bloggers and get answers they really understand at my university we are trying to set up a program for first two years of college that is highly interdisciplinary and focused on integrating science education into curriculum as whole writing courses are great for this and it would be good in such courses those housed in humanities to know enough to be able to do more than analyze the rhetorics of science in texts and films of pop culture lone heroic scientist in day after tomorrow lone heroic scientist in state of fear naive liberal lawyers I realize the whole issue of audience is very difficult to solve thanks and great job gm Response Audience fair point I would say that we are writing for people who won t be too scared by 1 n x1 xn That means that someone else will have to translate for people who prefer the arithmetic mean or average of a group of n numbers is just their sum divided by n So the arithmetic mean of 6 10 and 23 is 39 3 13 I agree with you there will indeed be people who prefer the latter Maybe you will have to do the translation William 34 greg meyerson says 27 Oct 2005 at 11 00 AM thank you robert g 35 Eli Rabett says 27 Oct 2005 at 11 36 AM For greg meyerson and others If you want to know the meaning of some mathematical or scientific term there are two good places to go on the net The first is the wikipedia http wwww wikipedia com the second is Eric Weisstein s world of science http scienceworld wolfram com 36 Brooks Hurd says 27 Oct 2005 at 12 03 PM Re 23 There are many reviews of the data by Jones Bradley and others Please aquaint yourself with the facts before posting Can you please direct me to Jone s data so that I can aquaint myself with the facts Thanks Response See the link provided to the Jones and Mann review paper mike 37 Lynn Vincentnathan says 27 Oct 2005 at 12 05 PM RE 28 moderator some argumentative language has been removed lets watch the ad hominem please We don t want flame wars on this site And for the millions who will die as AGW gets worse and perhaps the billions who may die IF runaway GW kicks in leads to the 6th mass extinction I think we must not let this happen Failure is not an option And it s not just millions or billions I m concerned about Each single life is precious and it s not good to be in the business of killing people That s my main point I do agree that Earth is not Venus some scientists have already told me how much they hate the label Venus effect but I find it informative simply because it gives some idea about the runaway global warming that did happen 5 times on Earth which later obviously stabilized back to livable conditions RE 27 moderator some argumentative language has been removed You probably didn t have the wonderful 10th grade education in ecology that I had so I can t blame you if you fail to understand that all life is connected along with the inorganic world and that killing off non human species could have negative effects on humans esp capstone species food crops livestock I also don t like false dilemmas like it s either them animals or us people I prefer to have my cake eat it too Now get busy finding out how we can save

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  • A New Take on an Old Millennium « RealClimate
    in greenhouse gases in the atmosphere 17 19 it follows that the best explanation for this ecosystem aberration is anthropogenic warming that has passed a threshold of natural variability So this record clearly adds to the weight of evidence that late 20th century changes are unusual in a long term context Of course this is just one record and a complex one to interpret It presumably reflects changes in the California current and in regional upwelling These features are connected at least in part with the El Nino Southern Oscillation phenomenon and ENSO has a somewhat counter intuitive relationship with natural radiative forcings Precisely how ENSO will respond to anthropogenic radiative forcing is still an area of active debate within the climate research community mike 8 John Finn says 10 Feb 2006 at 6 40 AM Regarding the reconstructions There still seems to be a problem whereby the reconstructions are unable to emulate the thermometer readings In fact by the end of the 20th century some are as much as 0 3 degrees cooler than the surface temperature record Which is incorrect the reconstructions the surface temperature record or both Response You appear to be misreading Figure 1 of our post which shows the instrumental series in black and the various reconstructions as coloured curves Some reconstructions do appear to underestimate the late 20th century instrumental warming e g Moberg et al the dark red curve many others however track it well or even slightly overshoot it e g Oerlemans the maroon curve So the basis for your assertion is unclear And my response to your specific question would be neither within the context of the estimated uncertainties in the respective curves mike 9 Matt says 10 Feb 2006 at 11 10 AM I have not yet read this article sorry I will do so now I being an anxious person wonder if we have done a single tree ring data set from 800 to 2006 without using thermometers at all 10 John Emery says 10 Feb 2006 at 1 27 PM Nice editorial Independent study 11 Ian says 10 Feb 2006 at 3 18 PM I am interested in the strength of the relationship between tree rings and temperature Do you know of any publicly available i e URL papers that go into this I suspect this was the type of thing done a long time ago Thanks Response Section 4 2 of the Jones and Mann 2004 review paper is a good place to start Jones P D and Mann M E Climate Over Past Millennia Reviews of Geophysics 42 RG2002 doi 10 1029 2003RG000143 2004 mike 12 Arthur Reader says 10 Feb 2006 at 4 17 PM Do you have information on why Osborn and Briffa used the controversial bristlecone pines when even the people who did the sampling Graybill and Idso made it clear that these measurements did not correlate very well with temperature It seems that whatever filtering Osborn and Briffa did make for proxy selection it appeared to be rather flexible in terms of what got in and what was excluded Response Perhaps you need to read and or re read the paper and our description of the paper Osborn and Briffa quite clearly describe an objective screening process which eliminated proxy series that did not correlate significantly with local instrumental temperature measurements over the 20th century So what you mean by rather flexible is unclear Their use of western U S tree ring composites which includes Bristlecone Pine data as we understand it specifically accounts for potential non climate related effects originally proposed by Graybill and Idso and explicitly estimated by Mann et al 1999 Corrected for these effects the data correlate highly with local temperature measurements over the 20th century They also use an independent 2nd western U S tree ring record that shows very similar behavior compare panels 1 and 3 in their Figure 1 to the first Furthermore their conclusions as described quite clearly in the paper are robust to the exclusion of both of these or in fact any 3 of the 14 proxy series used mike 13 Ian says 10 Feb 2006 at 4 23 PM Another question I m sure this has been debated at length so feel free to just point me to the appropriate blog article How do we know that tree ring widths are not just responding to increased CO2 and not increased temperature 14 Ian says 10 Feb 2006 at 4 32 PM That paper Climate Over Past Millennia relies on the correlation of temperature with tree ring width as proved by other people papers I was more interested in these other papers that prove this correlation I did see there was a reference to possible CO2 fertilization affect and it said this was compensated for but with no detail of course since that is not the purpose of this paper presumably the other people papers have evaluated this relationship Response Section 4 2 of the Jones and Mann 2004 review paper was intended to be a starting place If you read the various studies cited within that section you ll find lengthy discussions of these and many other issues related to the use of tree ring data in climate reconstruction I trust you ll be able to find answers to all of your questions therein mike 15 Rob Wilson says 10 Feb 2006 at 4 43 PM We also published a similar paper this week D Arrigo R Wilson R and Jacoby G On the long term context for late 20th century warming Journal of Geophysical Research Vol 111 D03103 doi 10 1029 2005JD006352 although our results are generally similar to the O B and earlier studies we cautiously conclude that there really is not enough data prior to 1400 to make such definitive statements about comparing MWP and recent conditions at least at these large scales Response Fair enough Rob D Arrigo et al is a nice contribution But keep in mind that your conclusions were based entirely on a particular RCS tree ring data set Osborn and Briffa s conclusions are based on an entirely different multiproxy dataset So there is no proper control in this comparison It might be interesting to submit your RCS tree ring data to Osborn and Briffa s methodology and see what conclusions are arrived at no mike 16 GMT says 10 Feb 2006 at 6 31 PM OT What do you guys know about this allegation of Lysenkoism on hurricanes and GCC 17 nanny govt sucks says 10 Feb 2006 at 6 43 PM Their use of western U S tree ring composites which includes Bristlecone Pine data as we understand it specifically accounts for potential non climate related effects originally proposed by Graybill and Idso and explicitly estimated by Mann et al 1999 How specifically was this estimate of non climate related effects done My understanding is that the MBH99 estimate of non climate related effects for the B cone pines increased towards the end of the 19th century then decreased in the 20th century This would seem to be inconsistent with the known path of increasing CO2 concentrations in the atmosphere through both the 19th and 20th century and the associated CO2 fertilization effect on vegetative growth Response Actually not It is well understood by those who study terrestrial ecosystem dynamics that there are multiple limiting factors on growth For example once a tree has essentially as much CO2 as it can use other conditions such as soil nitrogen availability will become limiting In addition the longer the stomates remain open to try to take in the additional CO2 the more vulnerable the tree becomes to water loss through evapotranspiration So one would only expect a significant impact of Co2 fertilization only until these other limiting factors kick in Any subsequent increase in ambient CO2 concentrations would have little incremental value to the tree once this happens A plateau in the observed response is the rule not the exception There is a vast scientific literature on this sort of stuff We ll leave it at that mike 18 Armand MacMurray says 10 Feb 2006 at 7 48 PM Re response to 17 You note There is a vast scientific literature on this sort of stuff Could you provide a reference or two to get us started Thanks Response I trust you can find the information all by yourself Try google scholar and start entering away mike 19 Mark says 10 Feb 2006 at 7 59 PM Could climate change alter and or accelerate the biological evolution of life including human life What kinds of selective characteristics would be favored in such circumstances perhaps they would favorable in that case anthropogenic climate change would be beneficial would it not After all green plants and plankton oxygenated the early atmosphere of Earth creating an environment that allowed new life forms to emerge 20 Timothy says 10 Feb 2006 at 8 06 PM Mike surely a bit of a mistake in your reply to 17 nanny If CO2 levels are higher then plant stomata will tend to remain open for a shorter period of time since the plant will more quickly be able to absorb the CO2 required for growth In fact this effect higher CO2 lower evapotranspiration has been cited as a contributor to increased run off in some river basins Your general point about there being multiple limits on plant growth is perfectly valid though In fact the major cause of the positive feedback on the land carbon cycle in Cox et al was the stomatal response to water stress closing the stomata to prevent the plant drying out thereby halting CO2 uptake and growth until water was available I also understand that even in ideal conditions where there is no nutrient or water shortage there is a limit on the growth rate of plants such that plant growth responds less to CO2 increases above particular threshold levels which vary from species to species On the other hand it so happens that CO2 levels vary massively in the sub canopy layer due to uptake by plants in conditions where air is not mixed downwards Consequently a higher background level of CO2 will reduce the albeit marginal effect of these CO2 troughs Response Thanks indeed you are correct I got it backwards in my haste mike 21 Timothy says 10 Feb 2006 at 8 19 PM Mark 19 Perhaps that would be true in an abstract creative destruction kind of way I would consider it very doubtful that the small mammals that scurried around the dinosaurs would have evolved into the vast panopoly of mammal species including humans were it not for the asteroid that caused the mass extinction at the end of the Cretaceous 65 million years ago I m less certain that the dinosaurs would have been willing to sacrifice themselves to enable the existence of cats and music by Beethoven although I certainly like both of those things Life will certainly evolve Gaia will respond Another mass extinction event will throw open a multitude of evolutionary niches for species to exploit undoubtedly producing an exciting array of new species In ooh about ten million years or so My main point is that any major disruption of the Earth s current biological systems will make it very difficult to support the existence of so many humans that exist and feel pain etc right now at the top of the food chain In this context serious systemic change in the behaviour of the world s climate and ecology is to be avoided at all cost 22 Justin Rietz says 10 Feb 2006 at 8 22 PM With all of these results graphed together it is a little hard to read However several things I note 1 Excluding the instrument data which we can t use to compare to 1000 years of data anyway it is apparent that we have seen temperatures comparable to today s over the past 1000 years Response Untrue Most of the reconstructions indicate late 20th century warmth that is unprecedented over the past 1000 years without any consideration of the instrumental record mike Having the instrument data in black and covering the other trend lines is well a little shady Response Watch the ad hom word choice This is hardly shady Most reconstructions have been calibrated against this target It would be odd not to show how the predicted and observed values compare over the calibration period Not showing that comparison might instead be considered innappropriate by some mike I think this graph would be more telling if this line was removed Response Most of these reconstructions are archived at the NOAA Paleoclimatology Data Center There s a link there from the RC front page Anyone is free to download the series and plot them any way they like mike 2 While it appears that the rapid increase in temperatures is unprecendented over the last 1000 years see my 3 there is a corresponding drop in temperatures beginning around 1000AD Wouldn t it be reasonable to believe that the climate pendulum swung in one direction and is now swinging back in the other direction as a response Response Not really Much of the observed variability is captured by models forced with estimated natural volcanic and solar forcing in the past and the added contribution of anthropogenic forcing in the 19th and 20th century There is no evidence that the long term radiative forcings follow an oscillatory pattern on multi centennial timescales though multidecadal roughly 88 year periodicities have been argued for in the case of solar forcing The Jones and Mann 2004 review paper linked above provides a good discussion of all of this and a good starting place for those interested in researching in greater depth mike 3 The rapid increase in temperature apparent in the graphed data lines over the last 200 years or so is somewhat misleading more recent data is more accurate so it tends to correlate and cluster more closely whereas the different data lines disperse the further back in time the chart goes making temperature trends in the past look more flat Response There is no reason to believe that more recent data is more accurate with most of these reconstructions Some use a time dependent proxy data set but others use a fixed set of proxies with reliable annual dating no reason to believe the estimates are any more uncertain in the more distant past than in the less distant past in those cases mike I would be interested to see each of these temperature lines graphed separately available some place Response See above mike Justin 23 J Sperry says 10 Feb 2006 at 8 23 PM Mike I believe you mean Section 2 3 of your paper not Section 4 2 in your responses above 11 and 14 The question was about tree rings vs temp and Section 4 2 is largely about MWP and LIA Response I meant section 4 2 since this is where the issue of how tree ring data have been used specifically in surface temperature reconstructions is discussed However section 2 3 provides some general background information on the use of tree ring data in climate reconstruction more generally which might be useful to those looking to learn more about the subject I would recommend this as a starting point rather than the final word The references contained within these sections provide a lot more detail on the subject Thanks mike 24 DrMaggie says 11 Feb 2006 at 10 27 AM Re 18 starting point for a literature search on plant growth response I recently took a course on ecosystem responses to climate change and the recommended course literature included Ecological Climatology by Gordon Bonan Cambridge University Press 2002 I found this to give a pretty good although somewhat wordy overview of the title subject and I learned a lot about how plants function and interact with their environment from reading the book It might be a bit too detailed for what you want Armand but why not ask your library to find a copy Another good place to start looking for climate related stuff is actually the good ol trusted IPCC 2001 TAR The concepts of stomatal regulation i e what Mike Timothy were mentioning above and how plant growth is influenced by climatic and abiotic factors is discussed in several places in the TAR see eg chapters 3 and 7 in the report of Working Group 1 as well as chapters 4 and 5 in WG2 See the IPCC TAR index page which also has a limited search function 25 jae says 11 Feb 2006 at 11 48 AM re 21 My main point is that any major disruption of the Earth s current biological systems will make it very difficult to support the existence of so many humans that exist and feel pain etc right now at the top of the food chain In this context serious systemic change in the behaviour of the world s climate and ecology is to be avoided at all cost How do you propose that we prevent change 26 jae says 11 Feb 2006 at 11 53 AM Would someone please address Steve McIntyre s assertion that none of these studies show late 20th century warming unless they include a few controversial tree ring data sets Response One gets the impression sometimes that data sets are defined as controversial purely on their 20th century characteristics The O B study demonstrates that the issue of calibration is not key to determining whether the patterns of warmth seen in these long proxy records demonstrate an anomalous late 20th Century Since the methodology say Jones and Mann vs O B etc isn t so important for this conclusion the argument then shifts to the suitability of the proxies As has been said eleswhere the number of suitable proxies for this kind of excercise is limited The recent D Arrigo paper has a few more that also demonstrate the same thing and O B s result is robust to the removal of any three of the proxies Since this methodology is relatively straighforward any other proxies can be easily added in to the mix and hopefully will be The more data there is the less important any single proxy will be however given the data we have so far the result seems to be robust gavin 27 Hank Roberts says 11 Feb 2006 at 12 50 PM how See everything in the sidebar to start with Read up on the subject of the site To avoid systemic change don t act in ways that may change how the system works That s not preventing change That s keeping it working Your circulatory system you don t want to prevent your blood from circulating so you avoid systematic change in the way your heart functions As German rocket scientist Willy Ley said long ago analysis is a fine tool but you cannot figure out how a locomotive works by melting it down and analyzing the resulting mess Think about yourself you no doubt avoid systemic change in your health you don t overeat you don t drink too much you watch your cholesterol levels you don t start your car running while the garage door is closed Think about your car you no doubt avoid systemic change all the time you check the tire pressure you use the right oil and change it regularly you keep the level of brake fluid above the bottom of the reservoir so no air bubble gets in you keep the cap on the brake reservoir so no moisture contaminates the fluid You work to avoid changing your system s operation when you don t understand how your system works because you know it s possible you may prevent it from working at all When it s just you hey it s just you But if your family s in the car you probably drive a little more between the lines and keep the brakes in a little better shape don t roll a stop sign or take a chance on a railroad crossing If you pilot an airliner or operate a nuclear plant well d oh Keep the needles out of the red zone the hood ornament between the painted lines Keep it moving don t screw it up 28 Roger Raphael says 11 Feb 2006 at 2 43 PM Please forgive the digression but in today s NYTimes John Tierny claims that AGW can be mitigated by geo engineering schemes to cool the planet by blocking sulight What s he talking about On the Simpsons once Mr Burns had a plot to blot out the sun but it wasn t a good thing Response There is a 1992 NAS report http fermat nap edu books 0309043867 html see chapter 28 William 29 Timothy says 11 Feb 2006 at 3 17 PM Re 28 I did see an idea whereby a large number of large ocean buoys would be manufactured that would float around and increase the amount of salt that would leave the ocean not sure of the mechanism The idea was that the resulting increase in aerosol would increase the brightness and lifetime of low maritime clouds increasing the planetary albedo Seems to me that it would be more reliable to manufacture wind turbines and start to burn less coal and oil There s also long been proposals to seed the ocean with iron in order to increase removal of CO2 from the atmosphere by the ocean I think they actually did some experiments with dumping iron and taking measurements of the consequent biological activity but I don t remember what the conclusions were I don t think it is going to add up to a get out of jail free card though Re 25 As 27 points out the key word in my sentence is systemic I propose that in order to reduce the risk of serious systemic change that we reduce GHG emissions In time we may well learn enough about the Earth s climate to be able to purposefully make fine tuning adjustments to our forcing in order to keep ourselves in a comfortable interglacial At the moment though I think we should just stop poking the beast As a side note there would be part of me that would be slightly disappointed were we to succesfully stabilise CO2 concentrations at 400ppm There s a part of me that wouldn t mind seeing how the experiment turns out When would the Atlantic THC judder to a halt How fast would the Greenland ice sheet start to melt I think we would learn quite a bit about various processes in the climate system by pumping out CO2 and observing what happens Unfortunately this isn t a lab experiment We have to live here so I think it is wise not to mess with it too much 30 Stephen Berg says 11 Feb 2006 at 7 08 PM Re 26 Would someone please address Steve McIntyre s assertion that none of these studies show late 20th century warming unless they include a few controversial tree ring data sets The only way one would not see a late 20th century warming from these data sets is if you had the graph upside down If McIntyre cannot see the late 20th century warming I d suggest he get his eyes checked 31 Mark Shapiro says 11 Feb 2006 at 8 20 PM Re 25 and 27 How do you propose that we prevent change We cannot prevent all change of course but my vote for the best take on energy policy is still with Amory Lovins at the Rocky Mountain Institute http www rmi org He s been discussing energy efficiency and renewable sources since 1973 and looks at the economics technology and policies to move the technologies into the market Their latest book about transportation efficiency is on their website available free in its entirety as well as much other material As for Mr Tierney in todays NYT I would direct him to RMI as well There are many reasons besides global warming risk to reduce fossil fuel use more wealth health and security Somehow Tierney thinks wind turbines and hybrid cars are expensive but geo engineering will be cheap Yikes 32 Pat Neuman says 11 Feb 2006 at 9 16 PM Instead trying to make sense of controversial tree ring data sets I ve spent much of my time looking at temperature data sets and fossil records from the late Paleocene and early Eocene Classic greenhouse warming with upper latitude amplification is shown in temperature 100 110 year plots for climate stations in the northern Great Plains Upper Midwest and Alaska Winter month average daily minimum temperature show the strongest warming trends Summer month average minimum temperatures July August are warming in central and northern Minnesota the area where the moose populations have been decreasing at alarming rates Kare11 Rick s special program on climate change in Minnesota earlier this week at http www kare11 com news investigative extras extras article aspx storyid 118105 Update Plotted temperature averages 1888 2005 monthly annual for public view at http pg photos yahoo com ph patneuman2000 my photos Photos from Fossil Butte National Monument and pictures of late Paleocene and early Eocene can also be viewed at the link above 33 Ian says 12 Feb 2006 at 12 57 AM Re 11 correlation of tree width with temperature For anyone that is interested I found a good paper that shows a very strong correlation here The correlation is amazingly good It makes me want to go out for a trek here British Columbia Canada and try it out myself with a tree stump that it has been cut down already by logging companies 34 Georg Hoffmann says 12 Feb 2006 at 3 36 AM Mike excellent post I have a question about the representation of the tropics in those NH reconstruction Are they not underrepresented in all Milleniums reconstructions And is this not a general argument for a slight possible bias of all reconstructions towards overestimated variability Cheers Georg Response Thanks Georg a very good point In a good number of the reconstructions the sampling is largely of the extratropics and the estimates largely represent extratropical temperature changes e g Esper et al 2003 In others the sampling is in both the extratropics and tropics but more weighted towards the extratropics e g Jones et al 1998 Mann and Jones 2003 Oerlemans 2005 Moberg et al 2005 In yet others there are more proxies in the extratropics but an attempt is made to appropriately weight patterns of surface temperature that emphasize both regions based on the relationships of those patterns with the available extratropical and tropical proxies e g Mann et al 1999 These differences in regional representativeness rather than statistical methodology appear to be the primary factor responsible for differences between various estimates Rutherford et al 2005 As alluded to in our post one important issue is the possibility that changes in El Nino may have significantly offset opposite temperature variations in the extratropics moderating the influence of the extratropical Little Ice Age and Medieval Warm Period on hemispheric or global mean temperatures e g Cobb et al 2003 mike 35 Erica says 12 Feb 2006 at 4 37 PM On slightly different subject could you guys give some insight into the cancellation of the Triana Deep Space Climate Observatory According to an op ed in the New York Times subscription only the cancellation may have been politically motovated and deprives the scientific community of an vital source of data on global warming According to R Pielke Jr it wasn t really a high priority to begin with What do you guys think 36 Erica says 12 Feb 2006 at 4 59 PM According to Jeff Masters at the Weather Underground the unusually strong ridge of high pressure that steered so many hurricanes to the US in 2004 and 2005 was formed in response to a strong warming of the ocean in the central North Pacific He cites observations made in Dr Bill Gray s SUMMARY OF 2005 ATLANTIC TROPICAL CYCLONE ACTIVITY for this connection Does anyone have any more information about this I know this is off topic but the hurricane thread seems to have been terminated 37 Terry says 12 Feb 2006 at 9 49 PM Something has always puzzled me about the Wikipedia chart The black line zooms high above all the colored lines at the end of the period 1 Why don t the colored lines go up too 2 Since the colored lines don t match the black line at the end of the period what does it prove that the colored lines have historically been below the high point of the black line To put it another way what is the evidence that the method used to construct the colored lines is capable of detecting temperatures as high as the high point of the black line Thanks in advance for the educational lesson Response We didn t create the Wikipedia plot so you d need to consult the authors of that page to get specific details However certain features are easily explained In most cases the reconstructions only goes through about 1980 because relatively few proxy series have been updated to the present many of the proxy series were developed decades ago So the interval of overlap between the proxy data and instrumental record is 1856 1980 or so In many cases the skill of the statistical model outside the calibration interval is established through statistical verification tests For example half of the say 1856 1980 interval is used for calibration and the other half is used to test the performance of the reconstruction and then the role of the two halves is switched Such exercises also provide an estimate of the uncertainty in the reconstruction which informs comparisons of recent instrumental changes with the longer term reconstruction The Jones and Mann 2004 reference discussed above provides detailed discussions of all of these issues and links to many other studies mike 38 Justin Rietz says 13 Feb 2006 at 11 15 PM RE Response 22 Thanks for the responses One quick question these plots are for northern hemisphere data only isn t this an inaccurate way to show global warming 39 Matt says 14 Feb 2006 at 7 27 AM Mankind s crime in global warming is that we time shift carbon oxidation moving it forward so to speak All biology fundamentally sequesters carbon providing fuel to drive the glacial cycle We have too much carbon forcing precisely because the biomass was too energetic some 20 000 years ago Man and other biological processes take advantage of the carbon oxidation by controlling it and extracting work The work generally is to sequester carbon Consider the old growth southern and northern forests That carbon is not oxidized it is sequestered in the great cities of the east and west coast while the old growth has been replaced by carbon fixing grasslands and new growth The new growth is sinking 2 million tons of carbon a year So now we have basically four forests in sequester when nature might have just burned off the original two forests and triggered warming decades ago How much carbon have we locked up in irrigated soils Our crime is that we use carbon energy and for each 10 atoms of carbon we sequester one carbon escapes We have so much carbon under management that the amount of energy needed to keep it sequestered is more than the atmosphere can contain What if man disappeared Well the glacial cycle would just oxidize the soils now left unirrigated our great cities would rot releasing hindreds of tons of carbon the new growth forests might burn off 40 Robert Simmon says 14 Feb 2006 at 2 16 PM Re 35 I work at NASA Goddard Space Flight Center not Goddard Institute for Space Studies where Triana was built but was not directly involved in the mission In my opinion and I m speaking here as a private individual not as a representative of NASA the mission cancellation is neither surprising or that much of a loss Triana evolved out of Al Gore s idea to replicate the famous Apollo 17 Blue Marble photograph more for outreach than for science The scientific community at Goddard and likely NASA as a whole was then asked to come up with instruments that would benefit for the satellite s position at L1 I think it was regarded as potentially useful but something of a diversion from the main sequence of NASA Earth observing satellites such as the Landsat Data Continuity Mission which is mandated by congress but inconceivably not yet funded Since it was Al Gore s idea it s been understood since November of 2000 that the mission was dead even though the satellite was complete and sitting in storage Subsequently NASA Earth science as a whole has been battered and things will almost certainly get worse before they get better 41 Steve Sadlov says 16 Feb 2006 at 9 11 PM RE Bristlecone Pines Being familiar with the area from doing both a bit of seismic reflection profiling there as well as recreation I have to wonder whether Bristlecones at the tree line in the Whites and on the Eastern slope of the Sierra are more sensitive to moisture or temperature in terms of their growth characteristics What has made me wonder about this is firstly the wide temperature swings known to occur in the area trees living there are no doubt well adapted to dealing with a reasonably wide temperature range and secondly the fact that 70 80 of the available moisture there is from snow pack In other words Bristlecones must also be well adapted to slurp up the moisture during a few weeks a year like a cactus and be more or less dormant otherwise These characteristics raise interesting possibilities for example years of high growth may be years where there was a robust snow pack that lasted until late spring ranging into mid summer years with less growth may have been warmer and drier To wit my seismic profiling schedule was once delayed by several feet of snow still there late May That would have been a good year in terms of moisture availability during the growing season Whereas this year being a La Nina year pretty much sucks in terms of snow pack in the Whites 42 Steve Sadlov says 16 Feb 2006 at 9 17 PM RE 33 Much of BC has a Marine West Coast climate And at that it is well north within that climate area So as a result the frequency of drought stress is low as compared with areas further south in that climate such as Oregon or Washington More or less the variable of moisture at such a location varies less whereas temperature varies a bit more Years that have multiple breakouts of the cold air pool that generally occurs in the Yukon MacKenzie lowlands would probably cause the maximum stress whereas years where there was more onshore flow would be lower stress So yes I would expect decent correlation between temperture and growth characteristics in that locale Plus one other thing Trees that grow in Marine West Coast and Mediterranean for that matter climates are not as well adapted to a wide range of temperature as would be ones in more continental climate types 43 Hank Roberts says 16 Feb 2006 at 10 34 PM Triana the satellite was complete and sitting in storage Good grief 44 Steve Sadlov says 21 Feb 2006 at 8 10 PM Setting aside for a moment any debate regarding proxies such as

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  • Sir Nicholas Shackleton « RealClimate
    implications of his measurements and they literally transformed how we now view earth history For his discoveries he received many honors and awards He was a Fellow of the Royal Society a Foreign Member of the U S Academy of Sciences a Fellow of the American Geophysical Union and numerous other societies also honored him He was knighted for his services to science with Willi Dansgaard who made similarly far reaching studies of oxygen isotopes in precipitation and applied these to ice cores he received the Crafoord Prize considered as earth sciences Nobel Prize he was also awarded Japan s Blue Planet Prize the Milankovitch Medal and most recently the Vetlesen Prize Though he always considered himself just a geologist Nick had many other talents most notably in music He was an accomplished clarinet player and had a passionate interest in the history of that instrument He was considered a world expert for his knowledge of antique clarinets and he had his own unique collection At Cambridge University where he spent his entire career Nick gave lectures on Quaternary geology and paleoclimatology but he also taught the physics of music Perhaps it was his knowledge of harmonics that played a critical role in his understanding of orbital forcing and its impact on earth history At the tri ennial ICP conference Nick would always organise a Paleo musicology concert where the many musically talented scientists and occasionally their more talented children would entertain the rest of us Nick was a true Renaissance man and he leaves a very important legacy to both musicology and the earth sciences Besides all this he was a nice guy and an inspiration to all who came into contact with him Comments pop up 7 7 Responses to Sir Nicholas Shackleton 1 Matt says 21 Feb 2006 at 2 15 AM Well thanks Ray for explaining the oxygen isotope tool and by extension I understand how carbon isotope measurements are used You then sent me off looking as sea level and temp and that leads of course to the younger dryas event My google scholar search informs me that we don t yet understand the younger dryas but that event seems to be the mark the initiation of the holocene period Younger dryas seems like an aborted attempt to restart the glacial cycle but lacked sufficient forcing function so the switch did not flip the oceans circulation or bedrock had an extra moment to equilibriate robbing the glacial cycle of its momentum In fact a few hundered years earlier there seemed to be another abortive attempt After the younger dryas event CO2 levels no long follow the familiar relationship it had in past cycles Comparison with previous cycles Vostok Ice Core leads me to conclude the cycle is especially dependent on the CO2 forcing fuction right at the cycle midpoint Is there thought that successive glacial cycles have sequestered more and more carbon eventually robbing the cycle of co2 forcing 2 SteveF says 21 Feb 2006

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  • A Mistake with Repercussions « RealClimate
    by Von Storch for review Yes it seems to be more calculated than just an innocent mistake But peer review is supposed to be the guard against this kind of thing I think the journal should take some of the responsibility Response One shouldn t necessarily infer that Von Storch et al knew the result was wrong at the time they submitted it They should have checked more carefully but I wouldn t want to jump to the conclusion that they knew it was wrong at the outset As for peer review remember that peer review is a very imperfect process the more so for journals like Nature and Science where the author has only a very limited space to explain his or her methods The most crucial step in peer review will always be the self peer review that an author subjects his or her own work to Mistakes do get made by editors about the qualifications of reviewers I also know about some cases where editors have over ruled serious objections raised by reviewers Since the peer review process is confidential we don t have any way of knowing precisely what went wrong in this case If I had been sent the paper to review I m not certain I would have spotted the the clues that the result was wrong just from what the what was in the paper In retrospect it s clear enough and it was probably always clear to experts in the thick of the subject But keep in mind that reviewers are besieged with papers they need to look at and don t have time to do a lot of deep investigation The reviewers most likely to take the time to do that I recall from my own unhappy time as an editor are the authors whose work is being attacked and those are precisely the reviews that an Editor is most likely to over ride raypierre 12 Steven T Corneliussen says 28 Apr 2006 at 9 02 AM In my opinion Arthur Smith 7 asks a crucial question So I hope that a RealClimate or other appropriate scientist answers it directly reporting what is known about Science s rationale or explanation or lack of them and that Science s editor in chief Donald Kennedy then does too It looks like the e address for people to send their own queries to Dr Kennedy is science editors aaas org He s a serious man about questions like this I hope he answers this one 13 Robert Bucke says 28 Apr 2006 at 9 03 AM All scientists make mistakes including myself Diligent scientists double check and make few mistakes They don t rush half baked work off to Science All scientists make mistakes Decent scientists correct them rather than trying to cover them up The response of Von Storch et al is still an attempt to cover up an elaborate smoke screen trying to tell us the mistake didn t matter 14 TCO says 28 Apr 2006 at 9 12 AM Response to Gavin s in the post response to my 1 In certain regimes speeds Newtonian mechanics is equivalent to relativity In other regimes it is dramatically inadequate If the difference affects the answer significantly then yes the Newtonian work is WRONG If it doesn t affect the answer significantly then bringing in the newly discovered GR is a non sequiter If it s in a regime where both are equivalent then mistakes found in a method relying on Newtonian assumptions will also be mistakes with GR assumptions I almost get the impression that the comments about new methods and such are an attempt to deflect criticism of the earlier work Think about it this way Gavin made up example A The unit cell of gold was determined in 1900 to be 1 00 Angstroms using a lab scale X ray diffractometer B Now in 2000 comes out a paper using synchrotron radiation updating the earlier result and showin 1 0014 Angstroms to be the unit cell size C I come back and re examine the earlier paper and see that they made an incorrect assumption of space group The unit cell must be 1 50 Angstroms D Analysis the updated method is irrelevant to the critique of the earlier work If it were relevant than it would have in addition to using a more powerful X ray have corrected the earlier paper s space group and shown that the unit cell was 1 5021 E Capisce P s Please do not censor this post If you value truth seeking and debate you need to allow replies to replies and let the discussion proceed If you are weary of the subject I will understand if you don t continue discussion But I don t agree with the policy of on high reply and then disallowing a response Response Science works in many different ways Some new results do overturn exisiting assumptions and show that previous work was incorrect Other results sharpen results based on better measurements for instance that were within the uncertainties of the older work that actually happens much more often A good example of the first is the mass of the electron I should probably check but I recall that modern measurements are significantly outside the error bounds of the first estimates While a simple example of the second effect could be something like the age of KT boundary The only point I was making is that newer results do not automatically imply that older results are wrong gavin 15 TCO says 28 Apr 2006 at 9 35 AM I m also very interested in the comments about the Burger and Cubash paper implications 1 That paper was very critical of work and conclusions from some of the authors of this blog of MBH98 and presented a very interesting analysis to show this This blog s author s have never directly addressed B C s main thesis The full factorial of 64 methods that shows significant differences in the reconstruction by making changes to the method I m not saying you don t have a response but you haven t made it 2 In the arena of this particular topic I wonder if your implied criticism of B C for using the detrended data affects their central thesis Does the graphic showing significant variablity for the 64 method variations collapse if non detrended data is used Or is this a side issue Response There is a strong case to be made as above that the detrending variants are a priori not valid and so shouldn t have been included in their analysis Similarly the effect of the rescaling step is always shown to be positive and so this too can be decided a priori I don t know what the remaining 16 variants would look like However you can do better than all of these seemingly arbitrary choices by using better methods for instance as described in Rutherford et al 2005 and the results are very similar That is a much better test of robustness gavin 16 Eli Rabett says 28 Apr 2006 at 9 59 AM TCO s example points to an error without a practical consequence Those who were using the 0 1 nm more SI and HTML friendly value did not have their results distorted There is a very famous example of a bad measurement that did have consequences that rippled through physics and chemistry I have it from a professor who was involved as a graduate student and young faculty member According to him the sanitized version can be found various places on the net including http prola aps org pagegif PR v48 i11 p918 1 p918 when Millikan was working on his oil drop experiment he needed a value for the viscosity of air He assigned a graduate student to remeasure this more precisely than had been previously done The student not my teacher went to the library looked up previous work took an average and went off to the lab to set up his experiment The average of his first few measurements came up right on the average of the previous work The student wrote up his thesis and went off to either fame and glory or obscurity I don t know which Millikan finished the oil drop experiment using the viscosity value that he had been given and published About 10 15 years later an X ray method found a slightly though significantly different value for the electron charge There was a furious controversy The best line that came out of this is that Millikan was rumored to have said in 1910 God revealed the charge on the electron to me to my knowledge there has been no further revelation Remeasurment of the viscosity of air using several methods found that it was slightly but significantly different from the previously used value Enough to bring the oil drop and x ray determinations into agreement some 25 years after the original publication by Millikan 17 Eachran says 28 Apr 2006 at 11 49 AM This is a good and important post Establishing the truth and accounting for it is one of the most important responsibilities we have as members of humanity It is I would say one of the most significant features of late 20th century global society that collectively we have decided to reckon and account for the truth Everything from the Nuremberg trials to the Truth and Reconciliation Commission in South Africa to the setting up of international institutions to monitor a fairer world bear testament to this There is no ducking and weaving on this issue and especially not for scientists One of the components of this reckoning as I call it is the recognition of fault to say sorry I got this wrong or even on occasion I lied Another equally important component is to forgive and not to forget but to record so that future generations assuming we make it through global warming know Clearly the work of Mr von Storch is an egregious example of I wasnt too clever with my work and deserves criticism and he along with those implicated publishers or others should account for themselves to put the record straight What more Well we are all facing catastrophe with global warming and we need to be honest with each other and to tell the truth if we are going to survive Equally importantly we need to be vigilant for the next onslaught of the deniers This comment by the Group helps the process please keep going dont weaken and thanks 18 david Iles says 28 Apr 2006 at 12 05 PM I am an artist and not a scientist I have been following your discussion and a few others rather avidly in an attempt to understand the parameters of the problem and the way that science works in terms of how reliable the information we in the public are getting on GW I want to thank you all for offering me this free education Every chance that the public this includes Legislators get to dismiss GW they will jump on it We would love to continue with our northern lives in the way we have come to accept as normal As long as people can believe that the science is in dispute they will use it for justification The no need to act side of this argument will always be greeted with relief and open arms What the public needs is a clear statement of the science of GW and the opinion of the risks we are incurring by ignoring it by as many leading scientists as are willing to sign onto a statement to that effect See http www realclimate org index php archives 2006 04 global dimming and climate models Comment 64 for my suggestion Dr Hansen has done this As far as I can tell he stated his informed opinion and not scientifically verifiable fact This did not make itself clear in his statements to the press and that is truly unfortunate Clarity on where opinion starts and science ends is an extremely important distinction From what I have been reading the actual peer reviewed science on this most critical of issues is not fully formed Some scientists are saying we need to wait until we have a better understanding I fear this will bring a widespread understanding as we watch our planet irreversibly change from this wonderfully diverse and generous Holocene home we have always known to a inhospitable and truncated world where bird song is replaced with the death rattle and the western banquet we now expect becomes a hard fight to snatch food from the mouths of rats and cockroaches I have read in other discussions here about the inadequacy of personal responsibility i e busing biking hybrid cars etc and I am sure it is true this alone will not solve the problems we face I wonder how many of you would agree with this statement in order to survive this century we will require a world war two type focus and effort We will need to mobilize all of our energies intelligence and creativity towards an acceptance and implementation of policies for rabid change We will have to develop a system of peer review and techniques for modeling new technologies that can move with the urgency made necessary by our inattention and inaction of the past We will need to as they did in world war two require manufacturers and businesses to put up their resources to meet the worlds changing needs We will have to be willing to export ideas and technology because of the global nature of the problem And finally we will absolutely need to cooperate on a global scale to make this work It will require diplomacy and negotiation that has no precedent in history The start to all of this is up to climate scientist and the quality of the reporting on these issues That is why I request a clear unambiguous non jargon filled statement on what we can expect if we continue to move slowly or not move at all on global warming and the variety of causes and problems it presents to us as a species as well as all of our fellow species here on earth I apologies for the length of this comment and appreciate the indulgence of those who stuck with it 19 Dano says 28 Apr 2006 at 12 29 PM RE 14 15 and the lurking cheer squad Even though a few folks may wish the worldview they chose for themselves turns out to actually be true what raypierre says in 10 especially his When you do a calculation which appears to give radically different results from that of a generally respected researcher and when the result being questioned is considered important you don t immediately launch a holy war declaring the older result nonsense to all and sundry is what is left after you stop being distracted by the FUD phrases and hand waving The reason why certain people with vanity sites can t get cooperation is because of the italicized Who in their right mind wants to cooperate with someone who acts this way It s like insisting that the scam victim help with the perpetrator s accounting Now sadly this non cooperation conveniently and unfortunately allows the shills to paint the non cooperators with a brush full of bad actor paint Next we get thunderous denunciations from employees of think tanks in WSJ and other legacy media usenet boards echoing the latest WSJ op ed in such volume it becomes spam and finally certain decision makers repeating the spam as conventional wisdom It s time folks to stop playing the this deserves a serious discussion game and call it for what it is a game of recycling the same old tired arguments over and over regardless of their merit Period That s what it is Best D 20 raypierre says 28 Apr 2006 at 12 39 PM Whatever you can say about Senator Inhofe and you can say a lot he certainly did a very effective job at making the Senate aware of Von Storch s work What I m wondering about is where are the champions in the Senate of any party I m not picky who can effectively communicate the importance of Von Storch s error I don t want to sound political here I m trying to focus on the issues of communicating science From looking at speeches in the Senate it often seems to me that Senators arguing on the opposite side to Inhofe do not have a sufficient command of the science to make their side of the case effectively What do others think about the situation 21 Gavin says 28 Apr 2006 at 12 45 PM I have very little confidence that a anyone was particularly swayed by Inhofe s speeches and b whether anyone will be swayed by a step by step deconstruction of them There are plenty of sensible people on the Hill and the hard work of explaining the science mostly goes on behind the scenes and not on the floor The role of posts like this is to provide background and information but as others have pointed out Inhofe and others like him are not being driven by the science and so arguing at the level on the science is merely to switch the debate away from actual issues 22 Grant says 28 Apr 2006 at 1 11 PM Re 21 I have very little confidence that a anyone was particularly swayed by Inhofe s speeches and b whether anyone will be swayed by a step by step deconstruction of them The real harm caused by Senator Inhofe s statements to the senate is that they enter the congressional record and become fuel for contrarians not just in policymaking circles but in the public consciousness So entering the refutation into the public record is also important I very much doubt that Inhofe would be persuaded to behave any differently even if confronted with irrefutable proof Inhofe will remain in the senate until he is voted out of office by the people of Oklahoma If senators can show his naivete misunderstanding and primitive thinking on the senate floor it ll probably do more to persuade Oklahoma voters than any far more precise and forceful refutation on the pages of RC 23 Jean S says 28 Apr 2006 at 2 04 PM Sorry if this has been covered here before I could not find it from the FAQ but could you explain in layman s terms how the methodology in von Storch paper is inferior to that Mann et al study Thanks Response This is stated clearly in the Wahl et al abstract emphasis added von Storch et al Reports 22 October 2004 p 679 criticized the ability of the hockey stick climate field reconstruction method to yield realistic estimates of past variation in Northern Hemisphere temperature However their conclusion was based on incorrect implementation of the reconstruction procedure Calibration was performed using detrended data thus artificially removing a large fraction of the physical response to radiative forcing 24 Dano says 28 Apr 2006 at 2 10 PM it often seems to me that Senators arguing on the opposite side to Inhofe do not have a sufficient command of the science to make their side of the case effectively What do others think about the situation I fully agree for both sides I can t imagine anyone thinking Barton wrote those questions nor anyone thinking he understood more than 06 of the testimony Nor would I expect more than 2 3 of the House to either as the skills necessary to succeed as a politician aren t shared by scientists which is part of the problem The key though is whether staffers understand the issues or whether lobbyists have non understanding staffers ears Certainly in committee there should be enough sunlight leaking through that fact based evidence should sway decision making Best D 25 Grant says 28 Apr 2006 at 3 41 PM Definitely off topic my apologies What are the best RC posts about the attribution of global warming to anthropogenic causes 26 Hank Roberts says 28 Apr 2006 at 4 03 PM Grant start with independenet historical information copiously referenced Once you have this basic material read it s easier to understand the specific papers being discussed as new science here Start Discovery of Global Warming Weart The history of scientific research on climate change from the 19th century to the present told in a set of hyperlinked essays http www aip org history climate 27 Mark A York says 28 Apr 2006 at 4 58 PM I would assert that the articles offered in Science are high quality despite what cover art may not match up to some article contained therein Unless of course they aren t which I doubt 28 Michael Tobis says 28 Apr 2006 at 5 29 PM Re 18 If you are expecting a society reconstructing manifesto to emerge on realclimate you are asking the wrong folks Climate scientists are as is pointed out elsewhere on this thread not very good politicians just as politicians are not very good scientists I think the main policy issue we grappling with here is just how to get to a society which can tell the difference between good information and bad information That isn t as grandiose a task as you would have us take on but it s still enormously important and very difficult Realclimate s only policy mission is to get real science on the table and fake science off the table Frankly we seem to be at a loss as to how to do this It often seems that in debates with a strong technical component the side which is lying unconstrained by complex equivocal truth has the advantage As a general rule false issues are exagerrated and real issues are minimized Climate change is unfortunately just one major issue of several where the public and the political sector seems to have increasingly bad information Perhaps if we could reach the point where a network of trust were re established between genuine scientists and genuine centers of power and influence we could as a society make better decisions Failing that probably any major shake up would make things worse In most situations there are more ways to get things wrong than to get them right A society that can t use its knowledge effectively is not much better off than one that doesn t have it in the first place By the way let me recommend the movie Thank You for Smoking which is not altogether off topic here The story is a farce and the moive is not entirely successful but the methodologies at the core of the story are strikingly realistic as anyone who has been following the climate policy debate can attest The scene at the beginning where the tobacco lobbyist on the TV panel attacks the serious well intentioned and dumbfounded cancer specialist as if he were the most contemptible sleaze imaginable is at least to a climatologist well worth the price of admission 29 Grant says 28 Apr 2006 at 5 32 PM Re 26 Thanks for an outstanding resource However the actual question is What are the best RC posts about the attribution of global warming to anthropogenic causes Response We actually haven t done many on this though we have asked a couple of people in the D A community to guest post on the subject It is a bit of an oversight However you can start with http www realclimate org index php archives 2005 05 planetary energy imbalance for a poor man s attribution study The follow on paper is also interesting there is a pop sci on that available at http www giss nasa gov research briefs hansen 11 I ll see if I can t rustle up a post on your specific question though gavin 30 Eachran says 28 Apr 2006 at 6 23 PM I was thinking of doing a post on the accessibility of science following on from a number of your recent lead posts but I didnâ t looking after visiting family and friends for a few weeks distorts time Raypierre raises the issue again in 20 above I believe that the AGW argument is won From the trivial issue of people including some UK Government ministers using Prius as fashion accessories for example to the more serious issues where in France for example barely a day goes by without French TV running something on global warming or some Department somewhere boasting about its eco credentials Believe me many people in France are terrified about the future Only last night M Bayrou a respected centre right politician in a TV discussion highlighted global warming as the issue to be addressed But the accessibility issue goes somewhat deeper because it demands people to behave in a different way To think like a scientist requires a level of rationality that is unfamiliar to the lives of most people People like to survive in comfort they donâ t like to think about the consequences of their actions unless it is proscribed by law And as we know there are laws and there are laws I donâ t see Mr Newton or Mr Einstein embedded in the US constitution for example even though the laws deriving from the work of these two gentlemen have profound effects on the way we live I shall stop here and perhaps this weekend draft somethingâ but maybe notâ we shall see On Grantâ s request for a primer Father William recommended IPCC to me and I thought it was very readable and I believe Hank Roberts was it Sorry if it was someone else recommended Stanford University website which I thought was terrific Just click on the links and educate yourself and good luck it is worth the effort 31 WorldChanging Another World Is Here says 28 Apr 2006 at 8 22 PM Oops Sorry About That Climate Change is Real After All RealClimate today points out that the key piece of peer reviewed research used politically by climate denialists was well botched Today Science published an important comment 32 Dano says 28 Apr 2006 at 8 49 PM RE 28 It often seems that in debates with a strong technical component the side which is lying unconstrained by complex equivocal truth has the advantage As a general rule false issues are exagerrated and real issues are minimized Well this is the nub Statements of certitude and unequivocation are looked upon by the gullible as well equivocating aren t they The spam that is out there is certain in its citations and denunciation isn t it with certain notable exceptions of course Shouldn t we be able to focus on first how to show folk to first turn ON their BS detector and second fine tune it to as Hank is pointing out in another current thread ask very simple questions when one suspects the salesmen selling you certitude After all the denialists are all certain that they are correct whereas the scientists are not certain they are correct That basically is the difference here IMHO Best D Response That s the essence of the problem identified in Steve Schneider s oft truncated quote which if memory serves went something like Can we be honest or can we be effective I hope we can be both The skeptics certitude makes it tempting to respond by trying to appear more certain than we are which is a tendency that has to be resisted That s why I think it is so important to learn how to communicate the implications of uncertainty which do not generally imply that inaction is the best course raypierre 33 Eli Rabett says 28 Apr 2006 at 9 37 PM As far as a primer and as out of date as it is hint hint Jan Schloerer s climate FAQs at Bob Grumbine s site is still pretty good as are many of the other FAQs there http www radix net bobg 34 JohnLopresti says 28 Apr 2006 at 11 58 PM It is rewarding to see the inductive process supply a course correction as peer review serves an essential aim although some time is lost the colloquy on the internet has hastened the resolution in this instance It is a pity a briefly extant sortie of experiments depicted the hockeystick as resting on a tilted surface as it were thereby apparently yielding less climb along the vertical axis thru time Within the science community frameworks often create disparities The explanation of the applicability of Newtonian and Einsteinian physics in one comment in this thread approaches a way to appreciate each view for its utility as science s views obsolesce Separately looking only at the Einsteinian calculus there are proponents of various interpretations of some concepts and historians have divergent records of the specifics of some experiments But it is serving as a foundation for further development imperfectly though it be used 35 david Iles says 29 Apr 2006 at 10 28 AM Regarding 28 Thanks for your response Michael and for the movie recommendation Marcel Proust wrote in Swans Way The facts of life do not penetrate into the sphere in which our beliefs are cherished as it was not they that engendered those beliefs so they are powerless to destroy them they can aim at them continual blows of contradiction and disproof without weakening them and an avalanche of miseries and maladies coming one after another without interruption into the bosom of a family do not make it lose its faith in either the clemency of its God or the capacity of its physician And from Goerge Orwells original unpublished introduction to Animal Farm At any given moment there is an orthodoxy a body of ideas which it is assumed that all right thinking people will accept without question It is not exactly forbidden to say this that or the other but it is not done to say it just as in mid Victorian times it was not done to mention trousers in the presence of a lady Anyone who challenges the prevailing orthodoxy finds himself silenced with surprising effectiveness A genuinely unfashionable opinion is almost never given a fair hearing either in the popular press or in the highbrow periodicals Your goal of trying to build a society which can tell the difference between good information and bad information or as Dano puts it turn ON their BS meters while a noble one is hopeless with about half the population 53 of Americans believe that God created us in our present form and of those 44 think he did it 10 000 years ago exactly as the bible said CBS News Poll April 6 9 2006 these numbers have remained consistent every since they started asking this question 40 years ago I was not trying to get climate scientists to rebuild society I was trying to get you to make a simple one page and intelligible statement stating what we are likely to face as humans if we continue to move slowly on global climate change I was asking for a majority vote of informed opinion among climate scientists a petition not another long and technically complex paper on CO2 climate forcing or an argument about tipping points as compared to rapid climate change It is clear you love to argue the details and I can tell you all would love to nuance the whole issue to death but most of us just donâ t understand you We need a simple basic statement like If we do not put a major effort into addressing global climate change in the next twenty years we will severely impair most of humanity abilities to survive past 2100 I am a painter I understand nuance I spend days slightly changing colors to complement each other it is deeply satisfying but sort of irrelevant if polar and Greenland ice sheets flow into the sea farmlands dry up forests burn tundraâ s release there stored methane and the methane hydrates frozen in the oceans raise to the surface bringing the global temperatures up to where only scorpions and cockroaches can survive They may in time develop a system of aesthetics but it will probably be fairly different from my own The life threatening and eminent nature of this problem requires all of us to move outside of our area of comfort and at least make a clear statement about where we are heading if we do not make a widespread effort to change You are the people whose opinions matter because they are informed I know you all have opinions about this what can you agree on I suspect we will wake up to the realities of GW as the oceans seep into our houses and our forests burn Shouldn t we at least cry fire in a common language If I simply do not know what I am talking about could someone just take a minute to tell me please 36 Grant says 29 Apr 2006 at 11 02 AM Re 35 If I simply do not know what I am talking about could someone just take a minute to tell me please You know what you re talking about It was an eloquent appeal for what may in fact be a better strategy for reversing public misinformation 37 pat neuman says 29 Apr 2006 at 11 03 AM re 6 Ocean I do not know how many reviewers get a manuscript for a peer review process National Weather Service NWS supervisors send staff manuscripts to NWS scientific services branch for review My paper on earlier spring snowmelt runoff and increasing dewpoints in the Upper Midwest was sent to NWS Central Region scientific services but I received no reply I ended up giving my presentation at the workshop NWS Climate Prediction Center and Desert Research Institute in Reno NV 2003 without hearing back from NWS on whether or not my paper had been approved Thus I was not allowed to hand out my paper on climate and hydrologic change in the Red River basin and the Upper Midwest because the NWS scientific services did not act on my request to have it approved even though they had more than six weeks to review it How much time is usually needed by an agency staff to complete review of a paper If the scientific services branch approves the paper is it then considered peer reviewed 38 teacher ocean says 29 Apr 2006 at 11 20 AM Re Pat Newman It depends on the journal Some journals are quick like AGU American Geophysical Union journals will mostly have a decision with reviewers comments in 3 months I am reviewing a paper for an AGU journal which gave me 14 days to return my review Science and Nature do a quick pre review where in a week s time you know if they have deemed your paper appropriate to be sent out for review I ve served on panels for the National Science Foundation and know from that experience that each proposal is sent to 7 8 reviewers but if 3 reviewers respond NSF officers consider themselves lucky If they get less than 3 reviews for a proposal then a panel member s has to submit a review the proposal I recently had an experience with a scientific journal that illustrates the imperfection or maybe perfection don t want to sound jaded of peer review I submitted a paper to a journal let s leave it nameless and received 4 reviews On a scale of 1 excellent to 5 poor my

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  • Art and climate « RealClimate
    unusual As an amatuer photographer I prefer natural lighting when the sun is lower on the horizon Would someone studying all my pictures conclude there used to be no high noon 13 natassa says 9 Mar 2006 at 7 51 PM yeah Coby that is what I thought too artistic justice is probably not relevant in a climate change discussion per se I mean Leutze painted the crossing of Delaware 75yrs after the event I find art revealing life more interesting in this case or even better in Gary Braasch s photography Brooklyn last year Lovely post G 14 Tom Fiddaman says 9 Mar 2006 at 11 07 PM On a related note a new article in Science describes arctic ecosystem changes in part based on oral history A Major Ecosystem Shift in the Northern Bering Sea There s a brief story on NPR Effects of Global Warming Apparent in Bering Sea The NPR piece describes changes that are unprecedented in the long local oral history In the Science article Yupik hunters of St Lawrence Island for example have observed an increase in warm winds in winter and the replacement of stable pan and pack ice with brash and thin ice changes that affect their ability to hunt and fish along with fundamental changes in animal behavior Local subsistence hunters in Barrow Alaska continue to report more numerous gray whales than in any time previously Native hunters have observed changes in walrus behavior in response to changes in sea ice cover 15 Paul Dougherty says 10 Mar 2006 at 2 04 AM Bringing Art into this thread widens the horizons for discussion even under the constraint of Climate Change Why are the Arts included in the same school as Science Both claim to seek truth What is the difference Art depends upon the artist Two of them can look at the same information and then depict dramatically different images Both think that they are depicting truth However what they depict is not only what they saw but also something of themselves Their background conditioning education etc influences what they transmit The artist does not pretend to be an impartial observer His Art includes himself and he makes no apologies for it Science has always wanted to put an end to that Can we see what is actually out there without including ourselves Sorry we can try but we cannot Yet through good procedure a scientist can do what the artist makes no attempt to do he can minimize the observer s influence He can attempt to approach reality but he can never get rid of the observer Scarily enough the quantum has gone further and said that not only can he not be rid of the observer but he also even influences reality It is not surprising then that in climate science we see different conclusions based on the same observations Singer Lindzen Michaels etc have credentials as good as any on this site Why then do so many ridicule their positions That seems to me to be more of the posture of artists rather than scientists Like Art no Science is certain Climate Science is full of uncertainties as attested to by both the IPCC and NRC We will all be dead before these are minimized In the meantime is it not wise to stop attacking those who appreciate science but who do not share our observed conclusions Conversions from one point of view to the other happen every day Data is data Can we not reach out as scientists look for the common ground and come up with a plan of attack Can we quiet the doomsayers as well as the naysayers Can we not come up with a scenario that expresses our uncertainties as well as prudent action Should not this be our course rather than the constant arguing with an enemy who cannot be either identified or defined By definition scientists are open minded and try to see each others point of view Compromise leads to action and on this issue that is what is needed This site is for science yet I hope that this post as well as the topic itself are relevant 16 Mark Drasdo says 10 Mar 2006 at 6 57 AM Re the response to No 7 has a consensus been reached as to how long is the time lag between greenhouse gases entering the atmosphere and the resulting temperature rise feeding through the system completely Also I noticed comments made by James Hansen in notes of a talk he had given late last year linked from the GISS report on record global temperatures in 2005 stating that the percentage of emissions remaining in the atmosphere had remained constant at 46 despite the alarming increase in total emissions over the last 15 years Is there any expectation as to if and when the oceans and biosphere will slow their uptake of CO2 I had understood that the oceans would be able to absorb less as they warmed 17 Ian K says 10 Mar 2006 at 7 54 AM I don t know if I respect Singer Lindzen Michaels etc because I havent had enough to do with them I respect the scientists running this site because of their help and efforts If they get a bit testy sometimes I guess they have their reasons Do these skeptics give similar help and work for free Thats not a rhetorical question As an amateur I only understand GW to a certain level I have trust however that somehow the folk at this site might help me dig deeper In that spirit I have just read raypierre s article and postings on Busy Week for Water Vapour There he had a gentlemanly disagreement with another researcher and I appreciated the respect he showed I myself could only understand his simplified explanation to a certain level That article prompts me to fill some gaps Can anyone explain in simple terms or point me to info on How does long wave energy absorbed by GHGs differ from their normal thermal energy Is such absorbed energy convertible to thermal energy of a different wave length if say a molecule collides with another molecule If the bond of a GHG absorbs a photon of long wave radiation how long does it hang on to it How do GHGs get saturated by long wave radiation and no longer absorb Similarly is there a graph somewhere giving the solubility of CO2 versus temperature in sea water 18 John Finn says 10 Mar 2006 at 8 16 AM Current thinking about the Little Ice Age does indeed rely on changes in solar activity as a climate forcing However you are completely off the mark in trying to compare local changes in England with the nearly global warming we are seeing today Because of shifts in the stationary wave pattern regional changes can be much larger than global or hemispheric means Yes I know this I realise that the CET is only a small region but there are 2 points here Firstly the CET lows coincided exactly with solar activity lows so it s reasonable to assume that the cooler climate was more much more widespread than central england Secondly the CET is the only record we have so in a sense it is representative of the NH in general much as the few stations that were around in the 19th century were or are Also your point about Europe and the US isn t valid with respect to the CET The early 17th century CET record shows a consistent and sustained warming or recovery over a period of 40 to 50 years Believe me by 2050 the trend will be all too obvious even at the regional scale and then you ll be wishing it weren t I hope I m around to see it Just in case could you perhaps indicate sometime a little sooner when a trend will start to emerge Response The trend has already emerged It s obvious to all but the most prejudiced in the global means I was talking only about when the trend would become so obvious even at the local level that even those such at yourself will no longer be able to deny it raypierre 19 John Finn says 10 Mar 2006 at 8 34 AM Regarding the article where it says However in 1963 the Thames only froze down to Teddington significantly up river from London clearly showing that something other than climate was responsible for the recent lack of winter mid river frolicking Could that something be urbanisation or the UHI effect which I understand has beeen fully accounted for in the various surface temperature records Response How can an extremely cold temperature reading have been caused by UHI gavin 20 Juerg Luterbacher says 10 Mar 2006 at 12 41 PM Gavin very nice post Actually as you mention there is plenty of art and documentary weather and climate evidence from different places all over Europe which allow to reconstruct past climate and also extreme weather events for the past centuries For a nice review see for instance Brazdil et al 2005 Climatic Change 70 363 430 and references therein You mention the cold 1564 1565 over the British Isles Actually during that winter coldness was widespread over large parts of Europe up to 3 C lower temperature over central and eastern Europe compared to the 1901 1960 average For those who are interested in having a look at the spatial seasonal climate maps covering the last centuries please have a look at the links given below There you find European land surface air temperature and precipitation charts from 1500 2000 with respect to the 1901 1960 period European surface temperature anomaly maps from Luterbacher et al 2004 Science 303 1499 1503 and Xoplaki et al 2005 Geophysical Research Letters 32 L15713 Mitchell and Jones 2005 International Journal of Climatology 25 693 712 for the 1901 2000 period are available at http www giub unibe ch klimet recons TT 1500 2000 pdf European precipitation anomaly maps from Pauling et al 2006 Climate Dynamics 26 387 405 are available at http www giub unibe ch klimet recons PP 1500 2000 pdf Winter refer to the year where January is Enjoy playing with the maps and I hope they will be of use for some of you You can get pdf of those papers and many more related to past and present climate variability from http www giub unibe ch klimet pub climdyn html r2006 Juerg 21 Coby says 10 Mar 2006 at 2 02 PM Re 18 I realise that the CET is only a small region but there are 2 points here Firstly the CET lows coincided exactly with solar activity lows so it s reasonable to assume that the cooler climate was more much more widespread than central england Secondly the CET is the only record we have so in a sense it is representative of the NH in general much as the few stations that were around in the 19th century were or are Your first point is only reasonable within very strict limits It may be reasonable to take regional lows corresponding to solar lows as evidence supporting a hemispheric or even global response but it is absolutely not reasonable to estimate the magnitude of the wider response from that of the regional response Your second point is completely wrong The fact that data is regionally very limited does not somehow bestow rights of greater representation This is acknowledged in the global temperature records by not starting until there were sufficient fewer yes but sufficient numbers of stations with adequate distribution The better coverage later in the record is represented by the smaller error bars 22 Coby says 10 Mar 2006 at 2 06 PM Re 15 Paul These are nice abstract warm and fuzzy arguments and for the most part there is little to disagree with Unfortunately there is a jarring cognitive dissonance between said arguments and the specific realities of the climate change debate and especially with the players you mentioned by name 23 John Finn says 10 Mar 2006 at 4 32 PM Gavin Re your response to Post 19 where you say Response How can an extremely cold temperature reading have been caused by UHI gavin I think you might have taken my post out of context If you re read the article you make the point that 1962 63 I remember it well was at least as cold as previous winters in the 17th 18th and 19th centuries when Frost fairs were held on the Thames You then make the following comment However in 1963 the Thames only froze down to Teddington significantly up river from London clearly showing that something other than climate was responsible for the recent lack of winter mid river frolicking I was implying that the massive urbanisation of London during the late 19th and 20th centuries may have created a warmth which prevented the Thames from freezing as it ran through the more populated parts What I m basically saying is that even though rural areas might well have been as cold or colder than previous years London s urban heat prevented a total freeze up of the Thames Although 1962 63 was a very cold winter the most notable feature was the length of the cold spell rather than the extreme low temperatures The cold snap began on Boxing Day Dec 26th and ran through without a break until March This is most unusual for the UK where nowhere is more than about 70 miles from the sea The length of the cold spell would also explain the low monthly figures for January and February compared to other cold years 24 John Finn says 10 Mar 2006 at 4 48 PM Coby re 21 Your second point is completely wrong It s not wrong The CET record is the only record we have for that period It s totally inadequate I grant you but as they re the only observations we ve got we re stuck with them We don t have any other data Incidentally other later NH records do track the CET record using 10 year smoothing fairly well so it s not unreasonable to assume that there was a sharp dip and subsequent rise in NH temperatures during the late 17th early 18th centuries and even if the NH rise is not as large as recorded in the CET there s every chance it challenges the 0 5 deg rise seen in the past 50 years 25 Lynn Vincentnathan says 11 Mar 2006 at 10 07 AM Re 15 I haven t been following Singer Lindzen and Michaels lately I have an on going search on peer rev articles on GW and I haven t seen their names as of late Do they really still claim in 2006 there s no such thing as GW or that it definitely is not caused by humans or that the benefits will outweigh the harms for humans And do they really really believe those claims How about Crichton He should be changing his tune since some of his evidence against GW is now melting Do these types of people ever change or are they simply immune to evidence 26 Matt says 11 Mar 2006 at 12 17 PM I read everything I can find about the major issue I think the problem we might encounter is that Gavin figures out how to get temperature measuements to within 5 deg so we just go up to 1 5 from average and stay there sort of Holocene v2 0 Then a few hundred years later the next crisis level hits The plant genetic engineers have given us a real shot at taking co2 levels down to almost anywhere we want do can it economically and do it fairly fast The biofuels industy will be humming along at 1 5 deg and they will be stubborn But climate engineers can use this power now and using simple national park style technology they can put us at just about any co2 level we would consider Response Maybe someday but until then what you re proposing is just science fiction and not especially of the well researched type either You vastly underestimate the difficulties in sequestering carbon given over 2 billion years of evolution of microbial ecosystems to oxidize anything that can be eaten raypierre 27 Tom Brogle says 11 Mar 2006 at 12 19 PM Re 15 Lynn Global warrming is undoubtedly occurring Howevever is is not unprecedented it has happened in recent times according to Crichton as recently as the 1930s There is plenty of evidence for such warming but doomsayers say it could not have happened because CO2 caused the present warming and that it could not have been as warm in the past because CO2 was lower Response According to Crichton nuff said No reason anybody needs to pay any further attention to anything you have to say on the subject raypierre 28 Paul Dougherty says 11 Mar 2006 at 2 33 PM RE 25 Lynn all three are quite visible on the web with Singer and Michaels having sites None of them can deny the temp data or the demonstrable greenhouse theory and they now agree that GW is happening They argue that there are too many holes in existing knowledge to extract the man made part and so predict the future They then predict the future anyhow and say that they expect past warming trends to continue at the rate of about 0 17C decade That is nothing to worry about they say as it agrees withe low end of IPCC projections and will probably bring many benefits as well as problems They could be right Unfortunately they spend too much time mocking the motives of others who see a more drastic outcome I imagine that is why they have lost so much respect and is probably what Coby was alliuding to above It is clear to me that it is undeniable fact that the earth is warming that the greenhouse effect is real and that man affects climate Despite the use of words like deniers I have not found a single voice on the legitimate climate blogs who deny this even though they are prolific elsewhere If I am right that the entire credentialed scientific community agrees on the qualitative nature of GW and disagrees only on its quantitatve nature then there is an opening for a unanimous position That would do in all of the outside deniers and open the door for real political action I am not the one to suggest a forum or offer a roadmap on how to get there There are certainly other possibilities But I think that it is action that all involved in this subject are looking for Jokes like Kyota will not work Our present path is just muddling through in which case we should all hope that the aforementioned trio are right in their projections 29 Coby says 11 Mar 2006 at 11 56 PM Re 27 Tom Brogle you do know that Michael Crichton is a science fiction author don t you Direct surface temperature readings tell us it is warmer now than at any time in the past 150 http www grida no climate ipcc tar wg1 fig2 1 htm this graph stops at 2001 http data giss nasa gov gistemp 2005 Borehole analysis tells us it is warmer now than at any time in the last 500 years http www ncdc noaa gov paleo globalwarming pollack html Proxy reconstructions tell us it is warmer now than in the last 1000 years http www ncdc noaa gov paleo globalwarming paleolast html Additional analysis going all the way back to the Holocene Climatic Optimum tells us it is probably warmer now globally than any time in the last 12000 years http www ncdc noaa gov paleo globalwarming holocene html http en wikipedia org wiki Image Holocene Temperature Variations png Before that was the last glaciation thus we can say it is warmer now than at any other time in the last 100Kyrs http www grida no climate ipcc tar wg1 fig2 22 htm What other global warming might you and Crichton be referring to for a full response to this standard misconception see http illconsidered blogspot com 2006 01 one hundred years is not enough html 30 Matt says 12 Mar 2006 at 1 21 AM Re the comment on 26 The problem is really the microbes and their effort to defeat us on carbon sequestering The microbe problem just gets worse the longer we wait because more carbon is coming into the land system The issue is getting enough carbon out to get down to some cold point that stops other carbon sources mainly from the ocean The evidence of carbon movement during the deglaciation indicates to me that the ocean is likely still producing net carbon If the ocean is still a net producer then you start a losing game of just keeping our head above water until you drop co2 levels to a point that stops net ocean production If we just let carbon pile up on land even if our emissions are zero then over time we have a diminishing capacity to find new places for carbon and you just accumulate fuel at high temperatures making the microbe problem worse 31 Eachran says 12 Mar 2006 at 9 07 AM I visited Lascaux II so called because it is a copy of the original for the first time last week Anyone wishing to visit should do so on a cold mid week March day the only other visitors were balding types like me and groups of very well behaved school children Very puzzling shocking instructive cave paintings clearly executed by a well organised and civilised society with time on its hands Given that the paintings were completed at the time of the last glacial maximum or thereabouts they are also a record of the times One needs to know that Europe was steppe and tundra in order to start understanding the cave paintings http en wikipedia org wiki Last ice age 32 tom brogle says 12 Mar 2006 at 11 00 AM Direct temperature readings of stations that are unaffected by adjacent buildings don t show any warming at all The total temperature rise is about 1 degree centigrade Tests that I have carried out in my locality show that it is quite easy to get a 1 degree or more differnce On the wall of a centrally heated building 5 2 12 ft away above flower bed 4 2 Town centre 500 yds away 5 5 field 500 yds in opposite direction 3 8 There was a light wind blowing towards the town centre from the field The area is 10 miles from the centre of a large conurbation If the the temperature changes so much over such short distances would not any new building in in the environs of a station cause it s to rise Since most towns annd cities have expanded over over the last 100 years and most stations are near to built up areas it is no wonder the surface temperature shows an increase in the last 100 yrs Don t tell me that the Sea Surface Temperatures confirm 100 years of warming they don t according to Graham Jackson in the comments to Happy Birthday Charles Darwin which should not need reapeating here Response Despite the fact that you persist in your erroneous conclusions about UHI you bring up a key point that might underlie your misconceptions You have correctly noted that the absolute surface temperature varies enormously on very short distances as a function of the terrain something that is true for rural as well as urban environments However temperature anomalies are much better correlated over large distances and this is why the global mean temperature calculations use local anomalies not absolute temperatures See The Elusive Absolute Surface Temperature for more details Had you kept your different thermometers in place for a while you would have noticed that gavin 33 JustAHouseWife says 12 Mar 2006 at 11 22 AM 29 Crichton is an author of fiction AND non fiction and he has an M D So You are a computer wiz So I am just a housewife who is married to a scientist who happens to be an environmental geologist So irrelevant off topic stuff deleted Response This blog tries to keep discussions focussed and with a reasonably high signal to noise ratio Each time that a comment thread degenerates into tired old arguments that are off topic and that just provoke a wave of extremely predictable point and counter point we lose an opportunity to actually have any communication I have my doubts as to whether you are actually interested in communication at all but try and surprise me and so don t be surprised that obvious trolls don t get make it past the filters gavin 34 David B Benson says 12 Mar 2006 at 3 28 PM Eachran s 31 reminds me where others of us might see climate related cave art pictures together with an interpretation of this work by a highly capable archaeologist who writes well R Dale Guthrie The nature of paleolithic art University of Chicago Press 2005 35 Eachran says 12 Mar 2006 at 4 14 PM Post 34 Thanks David I shall read 36 Coby says 12 Mar 2006 at 6 47 PM Re 32 Tom See here http illconsidered blogspot com 2006 02 warming due to urban heat island html 37 Dano says 12 Mar 2006 at 8 16 PM RE 32 This is of course well known You are measuring intensity not extent You want extent The literature is rich with empirical evidence on this topic Should you choose to visit a good Uni library do check out the literature Another hint you want to know where the GHCN stations are sited wrt your conurbation that is are they shielded from the UHI the literature will tell you Best D 38 Stephen Berg says 13 Mar 2006 at 3 26 AM Re the UHI take a look at David Parker s study summary in one of the November 2004 Nature issues The study is also to be published in Journal of Climate at a later date as it is currently in press His results show no significant difference in the temperature record from urban stations to rural stations http www realclimate org index php p 43 39 Steve Bloom says 13 Mar 2006 at 6 30 AM Re 15 Please please please check your sources before posting things that an easy check will show to be untrue You wrote Singer Lindzen Michaels etc have credentials as good as any on this site Why then do so many ridicule their positions Later in 28 you wrote None of them can deny the temp data or the demonstrable greenhouse theory and they now agree that GW is happening They argue that there are too many holes in existing knowledge to extract the man made part and so predict the future They then predict the future anyhow and say that they expect past warming trends to continue at the rate of about 0 17C decade As briefly as possible here s why they are ridiculed and a few details as to how you mischaracterized them and their views Pat Michaels The 17C decade temp increase prediction leading to the TAR low end projection for 2100 is Pat only He has no calculation to support this other than a straight line projection of the current rate i e it s supposition rather than science Note that things don t look so good for a 1999 prediction of Pat s http julesandjames blogspot com 2005 05 yet more betting on climate with world html Predictions aside Pat has been caught fabricating things on his coal industry funded World Climate Report site more times than I can count see the comments under the recent Greenland post on this site for details of the latest example He also lied to Congress about Jim Hansen s prior testimony In terms of qualifications Pat does have some i e a relevant degree but when it comes to what really counts publications that have broken new ground and stood the test of time he compares poorly to the RC authors Publication lists can be obtained through Google Scholar while their quality can be broadly judged by looking at citations Fred Singer He has been and remains a pure denialist http www sepp org keyissue html Notice that on the same page he has many other scientific conclusions that just happen to be extremely convenient for the short term profits of the industries that support him He was at one time a respected scientist but a look at his publications for the last ten years show only what amount to anti AGW opinion pieces which the journals were still willing to publish until recently and co authorship of a couple of papers based on the faulty assumption that the now discredited UAH MSU satellite was correct Lindzen is a little more complex and unlike Michaels and Singer it is not at all clear that his views are conditioned on payments from the fossil fuel industry He has done much good science in the past and is unquestionably a real climate scientist but seems to have gone emeritus on the global warming issue See http www realclimate org index php p 222 for a recent thorough discussion Note that Lindzen s current and I believe for some years now temp prediction is 5C for doubled CO2 which doesn t translate directly into Michaels figure but is clearly substantially lower There s lots more but that should be sufficient Response I would add to this that there is a real disconnect between Lindzen s activist testimony on climate change as typified by the House of Lords testimony and his actual peer reviewed scientific work on the subject There is actually very little of the latter and none of it has stood the test of time Aside from a very little work on estimating climate sensitivity from response to volcanic eruptions the only two real papers on climate change are the 1990 BAMS paper on a possible mechanism for negative water vapor feedback and the more recent BAMS article on the Iris mechanism He has some earlier general papers on climate change and ice ages but none of them has been especially influential in the field His big hits were his early work on atmospheric tides truly superb stuff his work with Holton on the Quasi Biennial Oscillation also very nice and on the role of gravity wave drag in mesospheric wind structure Back when I was a graduate student he wasted about a decade on a fanciful and largely mathematically pointless over reflection re interpretation of hydrodynamic stability theory Still because some of his ideas have proved to be very good in the past his work unlike that of Michaels or Singer which hardly even pretends to be science gets serious attention among climate scientists The mechanism proposed in the BAMS water vapor article was very carefully studied and does not hold up I don t think even Dick subscribes to it anymore though sometimes it s hard to tell The Iris paper gives an idea worth thinking about but the support for it given in the paper is very weak and subsequent research failed to turn up any particularly strong support for the idea I do think that even though the Iris mechanism is probably wrong the paper is a good addition to the literature because it will help stimulate some serious thinking about the very difficult issue of cloud fraction That point could have been better made without all the ill supported baggage concerning how it s a global warming killer amplified all out of proportion by people like Lomborg but on the whole I think work like that is a net plus So when Lindzen has something scientifically interesting to say scientists do listen His activism though mostly just trades off his general reputation to make claims that are unsupportable from any of his or others research raypierre 40 Richard Simons says 13 Mar 2006 at 2 10 PM WRT Michael Crichton s scientific credentials I have given undergraduate students an extract from one of his other books to see if they could find the five blunders on the one page His books may be entertaining but they are not a reliable guide to science 41 Paul Dougherty says 13 Mar 2006 at 4 22 PM Re 39 Please please please be very careful before you accuse someone of making untrue statements You do nothing to show that my statement that they have proper credentials is untrue rather you go on to confirm it Opinions are not credentials Because you feel that they have gone over to the Dark Side does not mean that they have lost their credentials and are not qualified to have legitimate opinions on the science For those interested here is something about their backgrounds Michaels http www cato org people michaels html Singer http www sepp org bios singer biosfs html Lindzen http www eaps mit edu faculty lindzen PublicationsRSL html Singer said in a PBS interview I have no doubt that an increase in carbon dioxide in the atmosphere should lead to some increase in global temperatures The question is How much Indeed he does not quantify and if he did his statements indicate that the number would be very small You agree that the 0 17C dec can be attributed to Michaels As far as Lindzen is concerned I will have to dig to find the lecture where he gave that I would like to mention however that the IPCC projections are based on scenarios which I believe are not the same thing as the CO2 sensitivity that you quoted Is that correct But quantities are not the point of my posts the fact that they agree that GW is happening is the whole point For those of us who are trying to translate climate science into political action and also for the public at large the credentials of an expert are what counts not the correctness of his viewpoints That is why such scientists are constantly testifying before some group particularly when those groups want balance Would you rather that they listened to Crichton and Gelbspan I mentioned above that these three loose credibility when they mock the motives of those who disagree with them which they have done When you use phrases like the short term profits of the industries that support him and payments from the fossil fuel industry in my opinion you join them 42 David B Benson says 13 Mar 2006 at 6 29 PM Re 41 39 The last paragraph by Paul Dougherty in 41 is worth rereading While we all can easily become angry and attribute motives until one is quite sure it is best not to attack Even when one is quite sure about motives it may still be best not to attack Stick to the sound science Thanks and I do enjoy reading Steve Bloom s comments 43 Stephen Berg says 13 Mar 2006 at 6 40 PM Re 41 Singer said in a PBS interview I have no doubt that an increase in carbon dioxide in the atmosphere should lead to some increase in global temperatures The question is How much Singer s comments inject exactly what he wants into the debate uncertainty when in fact there is little There are many models used by the IPCC which are indicating the same thing all dependent

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  • Addendum to “A Mistake with Repercussions” « RealClimate
    that detrending is simply an arbitrary choice in these kinds of methodologies but these results show that it is clearly deliterious to the skill of the reconstruction and thus there is an a priori reason not to use it 3 The problem of climate drift Von Storch et al 2004 started their model from an initial climate state that was in equilibrium with 372 ppm CO 2 which already includes the anthropogenic rise of carbon dioxide However their model experiment was meant to start at 1 000 AD when carbon dioxide levels were only 280 ppm Therefore CO 2 concentration was dropped in the model from 372 down to 280 ppm over 30 years followed by a 50 year adjustment period with constant 280 ppm CO 2 before the start of the 1000 year run proper Not surprisingly the global temperature dropped by about 1 5 ºC during this transition phase None of this is reported in their paper or online supplement This initialisation procedure is a rather unsatisfactory as it would be expected to cause a large climate drift during the experiment It is as if someone wanting to measure temperature variations outside was using a thermometer that he just brought out from a heated room If you looked at this thermometer before it had fully adjusted to the outside temperature you would see a cooling trend that has nothing to do with actual temperature changes outside Those experienced with coupled climate models know that the time scale to fully adjust after such a major drop in CO 2 concentration is many hundreds of years due to the slow response time of the oceans Even if the Von Storch team had not expected this problem they must have clearly seen it unfold the trend in their model during the transition phase reveals that it was far from equilibrium and they should at the very least have mentioned this problem as a caveat in their papers In the absence of this information many colleagues were puzzled by the strong cooling trend throughout the pre industrial era in this simulation which made it an outlier compared to all other available simulations of the past millennium Was this due to a particularly high climate sensitivity of this model Or was this due to the forcing used Correspondence with the Von Storch group brought no clarification Finally Osborn et al 2006 identified this as due to a climate drift problem The latest publication by the Von Storch team Gonzalez Rouco et al 2006 shows a second run with their model where the medieval time is about 0 5 ºC colder and the subsequent cooling trend to the 19th Century is only about half as large This shows that the medieval time was about 0 5 ºC too warm due the lingering anthropogenic warmth in their earlier model and about half of the long term climate cooling in their Science paper must have been due to the artificial drift Several further papers in other

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  • How Red are my Proxies? « RealClimate
    to test with a range of values for persistence to see whether a reconstruction method itself imposed an averaging or persistence on the data The issue is not only to test against a realistic set but to find limits of the reconstruction method if any exist Second if the year to year correlations vary between 0 15 and 0 30 it might be interesting to kick the can down the road and ask whether the persistence the rate itself is persistent This of course ignores the problem of noise in the data sets which might be the cause of the implied variation What is the year to year variation in instrumental data both locally and globally Does persistence change under strong forcing With that informtation more realistic test sets could be generated Response There is a vast literature looking at the AR 1 persistence structure in both proxy and instrumental climate data You might start here Mann M E Lees J Robust Estimation of Background Noise and Signal Detection in Climatic Time Series Climatic Change 33 409 445 1996 mike Third and this is a point I raised earlier in other venues is the issue of telecommunication in the models used to construct the test climates the reconstructed climates and the climate measurements It appears to me that this is a much more stringent test of all three and an issue that was only hinted at in von Storch and seriously addressed in the construction of global temperature records Ideally the results should match across the board Response I assume you mean teleconnections and this indeed a key point in the discussion Tests with model simulations are only useful if the large scale teleconnection patterns in the model are reasonably faithful to those for the real climate The erroneous initialization by Von Storch et al discussed in this previous RC post compromises any hopes for realism in terms of the teleconnection patterns in the model because the pattern of long term drift due to spinup problems is very different from the teleconnection pattern associated with real climate phenomena that are presumably important on the relevant timescales ENSO the forced pattern of response to volcanic solar and anthropogenic forcings the NAO etc By contrast the NCAR CSM 1 4 simulation of the past 1000 years used in the more recent Mann et al 2005 study is likely to be far more faithful to the real climate in its teleconnection patterns because there is no such long term drift present in the model surface temperature field analyzed mike Fourth the most interesting issue that von Storch raised was that the Mann reconstruction industry or at least the early MBH ones implies a very low climate sensitivity or overestimates of previous forcing Response This is not the case as long as the substantial uncertainties in both response i e the temperature reconstructions and forcing e g solar volcanic and anthro ghg aerosol are properly taken into account The range of sensitivities indicated by these reconstructions are consistent with the range indicated from other evidence e g the instrumental temperature record the Last Glacial Maximum estimates etc when uncertainties are taken into account mike How does this fit with the recent bounding of climate sensitivity within models and the historical record 15 Klaus Flemloese Denmark says 25 May 2006 at 10 52 AM I will be pleased to know the reply from Hans Von Stoch I am looking forward to se his reply on RealClimate if not please post a link Is it possible for him to run his simulation taking in consideration the corrections you have presented here 16 John P says 25 May 2006 at 11 00 AM So ad hoc von Storch et al fold in unphysical noise to their analysis and get a result that disagrees with Mann et al This verifies the old computer science dictum garbage in garbage out I agree with Don Strong this also provides evidence for the AGW denialist computer models have nothing to do with reality talking point 17 Jason Burford says 25 May 2006 at 11 33 AM 7 I read a related article on bbc website http news bbc co uk 2 hi science nature 5006970 stm Is it me or are the positive feedbacks continuously raising the bar 18 Nico Siegmund says 25 May 2006 at 11 49 AM thanks for the comment However I d like to read something on RealClimate about it I was reading the article on the PIK homepage but unfortunately the data provided does not suffice at least for me Would be nice to hear something by the professionals about it on this blog cheers 19 Hank Roberts says 25 May 2006 at 12 19 PM 17 Jason see responses to prior posting of same http www realclimate org wp comments popup php p 309 c 1 comment 13745 Search box at top of page will find links or subjects 20 Phil B says 25 May 2006 at 2 12 PM 11 12 I guess I am confused like Terry In Ritson s paper the third equation down it appears that the proxy data is differenced Y j X j X j 1 Phil Response We re checking with David Ritson for confirmation However the average raw lag one autocorrelation coefficient for the full set of 112 unprocessed predictors used by MBH98 is rho 0 28 with a standard error of 0 03 if the 20th century is not included owing to the argument that the natural autocorrelation structure is contaminated by the anthropogenic trend the value is lower rho 0 245 0 03 In either case the inflation factor is minimal compared to what is assumed by Von Storch mike Response update David Ritson confirms that the procedure in question is exactly as specified in the linked attachment and is designed to find within specified approximations the AR1 coefficient that describes the proxy associated random noise As mentioned above we ourselves independently find an AR1 coefficient for the combined noise signal between 0 25 and 0 30 for the MBH98 network close to the Ritson value and qualitatively lower than the value used by von Storch mike 21 MaTa says 25 May 2006 at 4 08 PM It is offtopic but I have a question and it would be great if someone answer Does anyone has a link where the greenhouse effect is described very detailled with scientific facts and mathematical equations and things like that I hope you understand what I mean I find always only very superficial views of the greenhouse effect Would be great sorry that my english is not very good Response The wikipedia entry on this is quite good and provides links to other very good sources of information mike 22 Phil B says 25 May 2006 at 6 16 PM 11 12 20 Mike Thanks for the clarification and update Since you obtained similar but slightly higher results then D Ritson can I assume you differenced the proxies like Ritson or did you obtain your results without differencing Thanks Phil Response No differencing precisely what was indicated above To repeat again the point made several times above the autocorrelation level of the signal noise i e the proxy as easily verified with synthetic examples from model simulations approaches the autocorrelation level of the noise component of the proxy under the assumption of low signal to noise ratios No differencing is required mike 23 jhm says 25 May 2006 at 7 02 PM Off topic Tropics are expanding study finds I thought that the tropics were defined by the titlt of the Earth s axis but anyway Response Tropics are expanding is a rather strange summary of what this very interesting paper actually means Rasmus and I will be doing a post on it as Part III of our discussion of circulation changes that accompany global warming raypierre 24 Phil B says 25 May 2006 at 7 18 PM 22 Mike Thanks for your quick response and patience Phil Response We re happy to answer good faith questions such as yours here Others however who seem to pose questions that gratuitously ignore answers already provided previously are unlikely to see their comments get screened through mike 25 Eli Rabett says 25 May 2006 at 8 43 PM Thanks for the long reply to 14 There are some points on which I still have questions First it should be useful to test reconstruction methods which have no internal physics against unrealistic data sets to explore the limits of the reconstruction method I certainly was not defending v Storch et al s data set Second while there is lots of noise in the data if the implied temperature sensitivity of a reconstruction is at the low end of the most probable range one has to seriously consider whether this is due to noise a problem with the measurements a problem with the reconstruction method or a problem with climate models Response We re only talking about noise here as a property of the proxy data so it cannot indicate a problem with any particular reconstruction method or model It the context being discussed noise is an intrinsic property of the proxy data themselves It is certaintly nonetheless a worthy question to ask what the source of the noise is In many cases its a sampling problem the ice core is only recording conditions at the time that snow is being deposited the trees are only responding to growing season conditions and can be influenced by threshold dependent processes not easily represented by seasonal means etc mike Finally you left me hanging on the issue of teleconnections does the NCAR model do a better job or has this issue not been considered If not is it worth considering Response As mentioned previously the model certainly does a better job in describing physically based teleconnections to the extent that the variability in the model is dominated by realistic climate signals e g ENSO the NAO which display meaningful spatial patterns of coherence in the climate field surface temperature of interest whereas the variability in the ECHO G simulation used by Von Storch et al is dominated by an unphysical pattern of long term drift whose pattern may have no correspondence with any real climate signal at all But aside from that one can certainly ask whether different models do a better job in their large scale teleconnections For example do the models exhibit realistic ENSO like variability The more realistic the model s ENSO the more realistic the interannual variability since this is one of principle climate phenomena that dominates coherent global scale variability on these timescales in the real climate Also relevant is the issue of whether the models in question exhibit large scale patterns of atmospheric response to e g the tropical SST perturbations associated with e g ENSO or to external radiative forcing changes e g volcanic solar and greenhouse gas that seem realistic There are many potential metrics by which the realism of a model s variability including its teleconnections might be measured This is the role of detailed intercomparison projects such as AMIP and CMIP and similar ongoing intercomparison projects described in the peer reviewed literature There is no short simple answer of the sort this model has better teleconnections than that model that would be satisfactory however mike 26 Hank Roberts says 25 May 2006 at 9 10 PM 23 that CSM article is good It answers JHM s question the Tropics Temperate Zone boundary was defined as described and they re describing a global change Someone also posted a link to the Mercury News s less clear article in another thread CSM From 1979 to 2005 the highest temperature increases in the lowest layer of the atmosphere the troposphere occurred in vast swaths centered on 30 degrees latitude Meanwhile the steepest cooling in the next layer of atmosphere the stratosphere occurred in these same regions The net effect researchers say has been to nudge the average paths of swift rivers of air known as the subtropical jet streams farther north and south These paths mark the meteorological border between the tropics and temperate regions 27 C W Magee says 25 May 2006 at 9 52 PM Re 23 The tropics can be defined either atsronomically or climactically The astronomical definition is the area between the tropic of capricorn and cancer This is defind by the Earth s tilt and changes by a few degrees over a 41000 year cycle The climactic definition is something esle maybe a climatologist can fill you in there But my guess is that it would be the warm wet low lattitude part of the globe in which frontal systems are a fairly minor part of the weather 28 Glen Fergus says 26 May 2006 at 6 32 AM Think you ll find that Russian guy s name is Markov Response I believe that the translation of the Cyrillic is non unique One can find translations of the Russian name to Markov Markow and Markoff I agree that Markov is more commonly encountered mike Why is it that Mann attracts such elaborately contrived criticism Response I ll take this as a rhetorical question mike 29 Woody Hickcox says 26 May 2006 at 9 37 AM According to the Koppen climate classification scheme tropical climates are those humid climates where the average monthly temperature is at least 65 F originally defined as 18 C 30 Eric Swanson says 26 May 2006 at 1 33 PM Re 17 The Torn and Harte article was published today on the GRL site GEOPHYSICAL RESEARCH LETTERS VOL 33 L10703 doi 10 1029 2005GL025540 2006 Missing feedbacks asymmetric uncertainties and the underestimation of future warming M S Torn J Harte Abstract Historical evidence shows that atmospheric greenhouse gas GhG concentrations increase during periods of warming implying a positive feedback to future climate change We quantified this feedback for CO2 and CH4 by combining the mathematics of feedback with empirical ice core information and general circulation model GCM climate sensitivity finding that the warming of 1 5 4 5 C associated with anthropogenic doubling of CO2 is amplified to 1 6 6 0 C warming with the uncertainty range deriving from GCM simulations and paleo temperature records Thus anthropogenic emissions result in higher final GhG concentrations and therefore more warming than would be predicted in the absence of this feedback Moreover a symmetrical uncertainty in any component of feedback whether positive or negative produces an asymmetrical distribution of expected temperatures skewed toward higher temperature For both reasons the omission of key positive feedbacks and asymmetrical uncertainty from feedbacks it is likely that the future will be hotter than we think published 26 May 2006 Might this be a good topic for a new discussion Response Indeed http www realclimate org index php archives 2006 05 positive feedbacks from the carbon cycle gavin 31 Steve Bloom says 26 May 2006 at 5 17 PM Re 28 I think an answer is useful for new readers of the site at least It s because the eye catching graphic from Mann et al the hockey stick so called because it shows a 850 year relatively flat graph of average Northern Hemisphere surface temperatures the handle followed by a sharply rising recent record the blade likely due to anthropogenic effects from circa 1850 was prominently featured by the IPCC Third Assessment Report TAR in 2001 see here Arguably the graphic was over featured relative to its importance to the TAR s scientific conclusions so that and the fact that paleodendrochronology is an endeavor with necessarily large error bars see the grey areas in the graphic made it the obvious point of attack for those wishing to undermine the TAR When I say over featured I don t mean that the science was in any way exaggerated but simply that it was the most impressive graphic available and so it got much more public exposure than other aspects of the TAR The irony of these attacks is that even a firm finding that natural variation made for a bumpier shaft i e a warmer Medieval Warm Period and a colder Little Ice Age wouldn t undermine the TAR s conclusions in the slightest see here Had there been no hockey stick available some other aspect of the science inevitably would have become the major focus for politically motivated attacks on the TAR While I m sure Mike has enjoyed his time in the sun the additional overwhelming evidence for anthropogenic global warming that has accumulated in the last five years has already served to radically reduce the ranks of the climate science deniers and publication of the Fourth Assessment Report AR4 should pretty well be the end of that chapter People like Inhofe and Crichton will probably go to their graves claiming that climate science is all a giant conspiracy and of course the science can never be perfect but after the AR4 comes out in a year I suspect they ll find themselves reduced to a status not much better than that of the Flat Earth Society 32 jonas says 27 May 2006 at 12 19 AM Did anybody read this article in the WP about the global warming sceptics very sad http www washingtonpost com wp dyn content article 2006 05 23 AR2006052301305 html 33 jhm says 27 May 2006 at 7 57 AM This BBC piece on noctilucent clouds seems to fit into many taxa of these climate change discussions It includes CO2 water vapor methane and just for fun space dust This is another off topic post Maybe there should be a seperate area devoted to discussion of press reports Really off topic in re Mike s response to No 28 substitute transliteration for translation 34 Demetris Koutsoyiannis says 27 May 2006 at 1 42 PM Having posted a comment earlier and waiting and trusting it to appear on RealClimate I take the opportunity to express my gratefulness to RealClimate and its contributors for hosting and disseminating some of my thoughts and ideas A couple of comments that I posted in another occasion were very kindly received and replied in RealClimate even though they might be different from the majority of ideas I read in RealClimate and subsequently widely read and disseminated I really appreciate this particularly because I have experienced difficulties in publishing my ideas including some of the articles I mentioned in my earlier comment and perhaps my style and thoughts in my earlier comment on this thread were influenced by very recent editorial experiences of the same negative type In addition I wish also to express my thanks to Professor Ritson because albeit indirectly he made two very important in my opinion points that perhaps I did not emphasize earlier 1 that statistics and stochastic processes are important in climatic research and 2 that we should recognize the large excursions over multi decadal periods in climate and hydrology Such a recognition is none other than a phenomenological or physical if you wish view of what is called in stochastic processes long range dependence LRD else known as long term persistence LTP Hurst behaviour scaling behaviour or long memory Here I would like to say that the latter term is in my opinion the worst of all because prompts people to think of a physical mechanism inducing long memory to climate or hydrology And since such a mechanism is difficult to imagine people are reluctant to accept this behaviour However if one similar to Professor Ritson recognizes excursions on multi scale periods and superimposes the excursions of the different scales one can obtain precisely the scaling LRD behaviour without the intervention of any weird long memory mechanism 35 Demetris Koutsoyiannis says 27 May 2006 at 11 27 AM Dear Professor Ritson With all respect to your work and with the risk of some misunderstanding because of my different scientific origin engineering hydrology I would like to make a few comments on your treatise Deriving AR1 Autocorrelation Coefficients from Tree Ring Data that you link in your above post and seems to be the background document for the post Response Dear Prof Koutsoyiannis I agree with you that instead of talking about simple Markoff processes I would be better to replace with stationary Markoff processes I should have added the condition that the record length be greater than alpha 1 alpha 1 the decoherence time To put things in context I was addressing a specific response of von Storch et al to a comment of Wahl myself and Amman that said It was realistic to believe that the proxy specific noise could be simulated with AR1 noise of a given variance and an AR1 alpha of 0 7 This is not consistent with actual data I was interested in your ideas on limits to more complex than Markoff descriptions I certainly would be interested in looking in a more leisurely way at what you have written and getting back to you I am however not sanguine as to how much further the data permits meaningful more complex descriptions I supply quick off the cuff answers to your specific points below David R 1 In my opinion it is useful that the author of a scientific text underlines the hypotheses which he she uses to derive the results and not leave the reader to guess them Response Agreed see above 2 Apparently you use the hypothesis of stationarity and ergodicity the latter is obvious from your notation which is in terms of time averages rather than ensemble averages Of course these are not strong hypotheses and everybody uses them however one must have always in mind that ergodicity has an asymptotic character e g a stationary process is mean ergodic if its time average tends to the ensemble average as time tends to infinity Papoulis Probability Random Variables and Stochastic Processes McGraw Hill 1991 p 428 Response OK 3 You also use the hypothesis that the process X j representing the growth amplitudes is an AR 1 process please note that I have dropped your subscript i to simplify notation as I am writing in ASCII mode Even though you put this hypothesis for a component of X j that you call noise amplitude it becomes also the case for the initial decomposed process X j given that you assume equality in time for what you call slow component Such a hypothesis is a strong yet unjustified one in my opinion there is no reason that nature s signals should be AR 1 Response No I assume ONLY that the signal climate temperatures is slowly varying with time and nothing else about its structure ie s j s j 1 and s j 2 are close to equal 4 Loosely speaking the AR 1 hypothesis is equivalent with an hypothesis that a single time scale e g the annual dominates in nature But I am glad to see in your paper the recognition of a signal component with comparatively large excursions over multi decadal periods So I agree with you that in addition to fluctuations on the annual scale there exist fluctuations on over annual scales In the case that we follow a multi scale thinking a maximum entropy consideration will result in a non Markovian non AR 1 dependence and most probably in a process with long range dependence LRD or long term persistence LTP This I tried to show in my paper Koutsoyiannis D Uncertainty entropy scaling and hydrological stochastics 2 Time dependence of hydrological processes and time scaling Hydrological Sciences Journal 50 3 405 426 2005 Response I assume along with everybody else that the climate signal contains regions of warmth Medieval warm period and Little ice age for example These may result deterministically from externals such as solar forcing 5 Even with a simpler thinking just with the superposition of fluctuations on three time scales e g annual decadal and centennial one arrives at a process that is virtually equivalent meaning for lags as high as 1000 years to a process with LRD This I demonstrated in my paper Koutsoyiannis D The Hurst phenomenon and fractional Gaussian noise made easy Hydrological Sciences Journal 47 4 573 595 2002 Response See answer to 4 6 From a more philosophical if you allow me to say standpoint viewing complex natural phenomena as AR 1 processes which means Markovian processes may be too simplified Recall from the theory of stochastic processes that a Markovian process is by definition a stochastic process whose past has no influence on the future if its present is specified Papoulis ibid p 635 Thus for me it is very difficult to imagine that only the present state of a complex natural system matters for its future and that we can drop our knowledge of its past On the other hand compared to a time independent like head tail outcomes in coin tossing view of natural processes in which even the present does not matter for the future certainly a Markovian view is a progress Response We are discussing proxy specific noise factors such as disease Higher order effects such as a tree that was diseased three yeara ago may be more or less susceptible this year are probaly out of reach 7 I was able to verify your main result in your treatise that alpha 1 2 rho where alpha is the lag one autocorrelation of the process X j and rho is the lag one autocorrelation of the process Y j as you define it Here I have used the notational convenience rho for your fraction in your penultimate equation I hope that my understanding is correct that this is lag one autocorrelation In my opinion there is no need to do as you did a decomposition of the process X t into a slow component and a noise amplitude I think that such a decomposition is fuzzy subjective and not necessary because you can obtain your result without any decomposition and without your accompanying assumption s j s j n which may not be justified If one simply defines Y j X j X j 1 i e in terms of the actual process rather than the decomposed one and also assumes an AR 1 autocorrelation function one directly obtains alpha 1 2 rho Response No I am afraid you are missing an essential point What one wants is the lag one autocorrelation of the process e j For simulation purposes the AOGCM program supplies the perfect proxies temperatures precipitation etc To get the simulated proxies one must add in one s best estimate based on real proxy data of proxy specific noise which is NOT provided by the AOGCM 8 However as I wrote above the AR 1 hypothesis is a strong one and it would be better to avoid it In this case one can easily obtain that your relation alpha 1 2 rho equivalently rho 1 alpha 2 becomes rho 1 2 alpha 2 alpha2 2 2 alpha where alpha2 is the lag two autocorrelation of the process X j Your formula is a special case of the general one obtained by substituting alpha2 alpha 2 i e assuming a Markovian process Given that alpha2 is unknown in an approach such as yours we cannot estimate alpha from rho But we can estimate its upper and lower bounds Assuming stationarity we can put the restriction that the size 3 autocorrelation matrix of the process X j is positive definite In this case a positive determinant results in the constraint 1 2 alpha 2 alpha2 1 From this constraint using simple algebra we can find an interval for alpha given the value of rho Response See above 7 9 You may say that this interval of alpha is too wide and thus not helpful in an accurate point estimation of alpha Well this is the optimistic view The interval for alpha would be that wide if we knew precisely the value of the lag one autocorrelation rho But we only have a sample estimate of rho thus the range of alpha is even wider More specifically in my paper Koutsoyiannis D Climate change the Hurst phenomenon and hydrological statistics Hydrological Sciences Journal 48 1 3 24 2003 I have demonstrated that the classic estimator of autocorrelation that you use implies high bias if the process exhibits LRD You may also find there citations pointing that bias exists also in the AR 1 process In addition to bias there also exists significant variability and thus uncertainty in estimates Therefore one should be very careful in such statistical calculations because they entail bias and uncertainty in contrast to typical arithmetic calculations Response Yes and no see above 10 Having some experience with statistical uncertainties and particularly with complex interactions of uncertainties and the magnification of the total uncertainty when ones combines two or more random variables in a single expression personally I would avoid calculating statistics of a process X j based on the differenced process Y j X j X j 1 or much worse on a process involving differences of some subjectively defined components of X j as you did You can check the magnification of uncertainty even with arithmetic calculations assuming for instance a pair of values X j and X j 1 close to each other and attributing a certain percentage of uncertainty in each of the two In this respect I would prefer to base my estimations on the process X j per se and in addition to be as aware and careful as possible of the uncertainty and bias in statistical estimations especially for processes which might exhibit LRD a case not well covered so far in classical statistical texts Response What is available are the simulated perfect proxies and separately ones best estimate of PROXY SPECIFIC noise Unlike in most engineering applicationscone is trying to create not the real world but an approximation to it One then applies ones chosen algorithm quite separate from anything I discussed to see how well it functions to extract signals buried in a noisy environment One is only validating signal extraction NOT setting values to the signal These are obtained when one applies ones analysis algorithm to real world data 36 Demetris Koutsoyiannis says 28 May 2006 at 4 31 AM Dear Professor Ritson Thanks for your kind reception of my comments and your responses Based on your responses I have the feeling that we can converge at least partially Therefore I will put my emphasis not to some different views that I may have for some of your points but to points that I feel we can converge I am happy that you assume along with everybody else that the climate signal contains regions of warmth Medieval warm period and Little ice age for example This could be a good point for convergence I also agree with your statement that These may result deterministically from externals such as solar forcing But I wish to discuss it further and first your term deterministically I hope you could agree with me that a specific storm that causes severe damages results deterministically from some atmospheric dynamics This dynamics is in fact the basis of the meteorological prediction of the storm cast some days earlier At the same time nobody would accuse meteorologists for not having predicted the storm a year or a century earlier Because of the complexity and chaotic behaviour we all recognize that it may be impossible to accomplish such a long term prediction Therefore in engineering given that we have to design works that will last say a century we use a probabilistic or stochastic approach to describe storms and to construct what we call design storm a hypothetical severe storm that has some pre specified probability of occurrence We could expand this logic to other simpler phenomena e g the movement of a die There is some deterministic dynamics in this movement however we all say that the outcome of the die is random cf Einstein s apothegm God does not play dice After this I hope you will agree with me that the Medieval warm period and the Little ice age are not MORE deterministic than the evolution of mean daily temperature or the mean annual temperature So if I have the right to use a stochastic description for the annual temperature as you did with your proxies I feel that I have the right to use a stochastic description for over annual fluctuations or excursions such as the Medieval warm period and the Little ice age Of course you may disagree with me You may say that these excursions should be modelled not stochastically but only deterministically In this case I will ask you Could you give me your deterministic dynamics for the variations of solar activity and their impacts to the atmosphere and particularly the global average temperature Could you apply your deterministic dynamics for the past and hindcast the climate over the last 2000 years Could you apply your deterministic dynamics for the future and forecast the climate over the next 2000 years In these questions I deliberately used long periods because we need long periods to observe such long term fluctuations As you see by profession I do not have any problem to use stochastic descriptions of natural phenomena In fact I am very satisfied with the answers I am getting from my stochastic descriptions for engineering designs and for supporting water management decisions But in fact in hydrology we follow the paradigm of physics In my knowledge and view in the late 19th century physicists abandoned the mechanistic paradigm and were thus able to develop disciplines such as statistical thermophysics including the entropy concept first put on probabilistic grounds by Boltzmann and quantum physics In both these disciplines probability has a major role and replaces mechanistic concepts explanations and analogues e g Lavoisier s subtle caloric fluid If we accept that one is allowed to use stochastic descriptions the question is Which stochastic description can be appropriate for hydroclimatic processes i e reproduce the Medieval warm period and Little ice age and the persistent droughts and floods of Nile I mentioned Nile because we have a lot of information covering many centuries â obviously such behaviours have been observed in other rivers as well A Markovian AR 1 description I would say no I have played a lot with several stochastic models and I think the simplest is a scaling model also known as fractional Gaussian noise and with many other names see my post in http landshape org enm p 25 Please allow me to say that a simple scaling stochastic model is not a complex description as you characterize it in your first response above It is a very simple description in some aspects simpler than Markovian And it has a very simple interpretation combine fluctuations or excursions on several times scales and you get a scaling process Amazingly the resultant scaling process by combining different initial components is simpler than the components But this may not be a surprise or a unique phenomenon Combine several weird distribution functions by taking the sum of the different random variables You get the extremely simple normal distribution the central limit theorem notably the normal distribution results also from the maximum entropy principle regardless of the central limit theorem Having said these it s a marvel to me that climatologists have been so strongly reluctant to adopt the scaling description for climatic processes I marvel to read statements that long term persistence is not a proper recognition of the physics and dynamics underlying the climatic systems and that â a simple model an AR 1 model for climatic noise has the advantages that it is i motivated by the actual underlying physics see e g Hasselmann 1976â the quotations are from a review

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  • National Academies Synthesis Report « RealClimate
    in the less contentious LIA than the MWP so I think the controversy over the MWP is set to continue particularly as most of the criticisms of MBH were accepted by the panel Overall I feel the NAS panel failed to grasp the nettle but have moved the debate forward 5 Bryn Hughes says 22 Jun 2006 at 3 06 PM So that we can say that we are not absolutely certain that the 1990s were warmer than the MWP Response Absolutely certainty exists only in mathematics not the real world gavin 6 Rod Brick says 22 Jun 2006 at 3 11 PM Why is it that science that agrees with our own notions preconceived or studied is precise and solid and that which doesn t is politics Response Why is this asked whenever the scientific consensus comes up with a statement someone doesn t like gavin 7 Brad Hudson says 22 Jun 2006 at 3 27 PM I m just an ordinary non scientist trying to sort all this stuff out This site has been invaluable in helping me understand the science I read the press release and then the conclusions section of the report I found the form of the conclusions both confusing and disappointing The report never explains what it means by high level of confidence less confident or plausible Listening to the press conference I understand that the first term means something like 90 95 confidence the second means 2 1 odds and the third means we can t quantify it at all I dont pretend to understand all the technical details in the report but is it too much for us lay folks to expect some degree of precision and clarity in the conclusions of a report of this type Response Agreed gavin 8 Bryan Smith says 22 Jun 2006 at 3 29 PM Is there any current way to better assess temperatures from more than 400 years ago or do more studies using current proxy methods just need to be done Response Fund more science to gather more proxies And to research new ones William 9 lars says 22 Jun 2006 at 4 19 PM So why is there also global warming on Mars Why does this not address global overpopulation of say the billion plus Chinese Indians Muslims At what population human and animal level does the earth need to be reduced to based on this study Why does this not address the global warming that has occurred since the last ice age which I find ice ages more of a problem then global warming There have been 60 glacial advances and retreats in the last 2 million years as noted in the link below Why does this not address eccentricity of the earth s orbit the tilt of the earth s axis and the precession of the equinoxes Or even plate tectonics continental uplift reduction of CO2 and changes in the earth s orbit All contributors to climate changes During each of these intervals many glacial advances and retreatsoccurred For example over 60 glacial advances and retreats have occurred during the last 2 million years If ice age is used to refer to long generally cool intervals during which glaciers advance and retreat we are still in one today Our modern climate represents a very short warm period between glacial advances http www museum state il us exhibits ice ages when ice ages html http www museum state il us exhibits ice ages Learn about plate techtonics continental uplift reduction of CO2 and changes in the earth s orbit http www museum state il us exhibits ice ages why 4 cool periods html Learn about the eccentricity of the earth s orbit the tilt of the earth s axis and the precession of the equinoxes http www museum state il us exhibits ice ages why glaciations1 html Response Why do you not address all the other topics of potential concern Why do you not look at the index Learn about the terms of reference gavin Response Re GW on Mars we ve done this already here William 10 Paul Biggs says 22 Jun 2006 at 4 29 PM There is another MWP proxy vineyards The History of the Wine Trade in England by A L Simon 1906 Towards the middle of the twelfth century we are told by William of Malmesbury vineyards were no longer confined to a few places but extended over large tracts of country producing a great quantity of excellent wine You may behold he observes when describing the fertility of the vale at Gloucester the paths and public roads fenced with apple trees which are not planted by the hand of man but grow spontaneously This district too exhibits a greater number of vineyards than any other county in England yielding abundant crops and of superior quality nor are the wines made here by any means harsh or ungrateful to the palate for in point of sweetness they may almost bear comparison with the growths of France In the reign of Stephen there is a mention in 1140 of two vineyards at Mealdon and in the same year the Sheriffs of Northamptonshire and Leicestershire were allowed in their accounts for the livery of the King s vine dresser at Rockingham and for necessaries for the vineyards There is also an Act of this monarch which is undated but which from internal evidence may be safely attributed to A D 1143 ordering that restoration should be made to Holy Trinity Priory London of its land in Smithfield which Geoffrey Earl of Essex had seized and converted into a vineyard In the fourth year of the reign of Henry II payments appear to have been made and charged to the Royal Exchequer for the keeper of the vineyard who received on one occasion sixty shillings and tenpence as well as for the expenses of the said royal vineyard Later on during the same reign in 1159 1162 1165 1168 1174 and 1175 there are frequent mentions of the royal vineyards at Windsor Purley Stoke Cistelet and in Herefordshire and Huntingdonshire in 1165 there is an entry of a vineyard at Tenham the produce of which seems to have been devoted to the sick at the infirmary During the first year of the reign of King Richard there are three mentions of vineyards and others occur during the reigns of Henry III at Lincoln Bath and Hereford of Edward II at York and as late as that of Richard II in 1385 and 1392 at Windsor II and Kennington At the beginning of Edward I s reign in 1276 Cantilupe Bishop of Hereford either planted or renewed the vine yard which his pupil and successor Swinfield had at Ledbury In 1289 the Bishop made seven casks dolia of white wine and nearly one of verjuice at Ledbury This wine was chiefly transferred to Bosbury another estate of the Bishop and it was mostly drunk during the ensuing summer Ledbury must have been particularly well suited for the culture of the grape vine since as late as the end of the seventeenth century Ah the LIA was bad news for wine production in England but it is booming again http www englishwineproducers com index htm Response By that proxy it is clear that it is warmer now since there is more wine produced today than there was 1000 years ago Still not very good to drink though I hear there are a few exceptions gavin 11 Michael Jankowski says 22 Jun 2006 at 4 39 PM Response Absolutely certainty exists only in mathematics not the real world gavin As an applied math major in my undergrad days I am deeply offended Plenty of math is real world I think this response should have been censored and the responder warned I can say with absolute certainty that it s warmer today where I live 90s than it was back in December when I was getting snowed on 12 Paul Biggs says 22 Jun 2006 at 5 00 PM Re 10 Gavin you are right I drink Californian 13 Steve Sadlov says 22 Jun 2006 at 5 22 PM RE 11 I can say with certainty that after one of the crummiest Springs in recent memory where I m at the current outbreak of a dry compressive interior SW US airmass is really nice I can also say with certainty that the inevitable coastal stratus and seabreeze that always follow with a vengence will have me breaking out my sweater by some time next week Also for what it s worth in this neck of the woods 1998 was a record cold year especially in the Fall snowed down to sea level of the last day of Fall that year For us it was 2000 that was the hot one an interior outbreak hit just right during high sun angle in late May and early June and it hit 115 F at my place I have no AC as is true of 90 of the folks in my immediate locale Not fun for some actual fun via Google looking up oddities such as Santa Anas Sundowners and Diablos and their ability to transform normally mild coastal areas into a weather pattern that is typically Iraqi for a couple of days can be quite interesting Variation makes life interesting Perhaps so long as I can have a cold Margarita 14 Zeke Hausfather says 22 Jun 2006 at 6 03 PM The Times has a story up about the report already While its not a bad piece overall the part near the end where they cite since discredited critiques of the original Mann et al article is rather dissapointing given that the only reported rebuttle is that the Mann et al paper made numerous caveats regarding uncertainties 15 Jason Rife says 22 Jun 2006 at 9 27 PM I am having trouble reconciling two points of the report as summarized in an AP article I am assuming they got the facts right Over the last 2000 years give or take the earth probably has experienced significant global temperature swings both hotter and cooler yet the levels of CO2 and methane have stayed fairly constant over the last 12 000 years except for the most recent history This alone would suggest that within the ranges over the last couple of thousand years CO2 and methane levels have had little impact on global temperature What am I missing Response Here are a few things you are missing First it s simply not true that there are documented temperature swings in the past 10 000 years that are clearly comparable on the warm side to what has been seen in recent times It is only for the past 1000 years that one can tentatively estimate hemispheric averages and there it is increasingly clear that the recent warming is unusual With regard to earlier times the main problem is that it is currently not possible to reliably estimate global or hemispheric averages from the proxy data so it is not possible to say if warming in the earlier Holocene were as widespread as the current warming That goes especially for the climatic optimum in the early Holocene which is almost certainly due to the Earth s orbital fluctuations specifically the precessional cycle There is some global mean signal from the precessional forcing but theory says the warming should be mostly regional and seasonal proxy data is largely silent on how global the real warming was at the time The second thing you are missing is that there are actually multiple causes of climate change and the existence of other climate forcings does not in any way negate the importance of CO2 Other things that have varied during the Holocene include volcanic activity solar activity and the precessional cycle Just because some of these things can also cause climate change doesn t mean that CO2 can t If you can die of cancer does that mean you can t die of a heart attack The final thing you neglect is that currently we are only comparing the relatively modest warming so far with the warming of the past several thousand years However so far we haven t quite gotten to 400ppm CO2 but we ll eventually go to 700 or more without controls We haven t even seen the full warming effects of that 400ppm yet because it takes time for the ocean to warm up So the striking thing is that it has already gotten to the point that the recent warming stands out from the natural variability of the past thousand years or more despite the fact that so far we ve only experienced the barest beginnings of the warming That s not just striking It ought to be alarming raypierre 16 e ou says 22 Jun 2006 at 10 01 PM In the interest of the public is it possible for real climate and climate audit to run a parallel analysis of the NAS report This may not resolve the debate but at least it will give us a more balanced approach than to go through the comments in each of the web sites I doubt if comparing the wine production in UK 1000 years ago and today would be a good proxy that the climate is warmer today The volume of wine produced is a function of a large number of natural and human factors other than climate One major factor is the preference to wine and acloholic beverages as well as the human population 17 Joel Shore says 22 Jun 2006 at 10 12 PM Re 14 What you are missing is correct logic If one variable has remained constant CO2 levels while a second temperature has varied you can t learn anything about the sensitivity of the second to variations in the first because the 1st hasn t varied It could be that temperature is exquisitely sensitive to CO2 In fact it could even be that the very small changes in CO2 drove those supposed significant temperature swings However in reality your premises are questionable too First while there have been some swings in temperature the evidence suggests that they have not been that strong And while CO2 has been fairly constant it has not been completely so Re 10 Maybe I am being ignorant here and someone with more knowledge of wines can clue me in but I have never understood how wine growing in England is much of a proxy We grow wine here in upstate New York and I can bet that at least our winter climate is considerably colder than it has ever been in England even during the LIA I also imagine our growing season is shorter Or is it the summer climate that matters more Response I never much liked wine growing as a proxy either it s too confounded by extraneous factors For example changes in the demand for liturgical wine owing to changing religious practices can alter the profitability of growing local low quality wine raypierre 18 Joel Shore says 22 Jun 2006 at 10 14 PM My above comment referenced to 14 is commenting on Jason Rife s post which I see is now labeled 15 19 C W Magee says 22 Jun 2006 at 10 23 PM re 14 Jason what you are missing is the difference between what is possible and what is probable Prior to 400 years ago large swings in temperature cannot be ruled out because to grossly simplify the error bars are too big for the older reconstructions This does not mean that large changes did occur during that time period It just means that today s body of knowledge is not sufficient to exclude large changes Wheras for the last 400 years we have enough data to say with some measure of confidence that variations were relatively minor re grapes Are grapes a proxy for growing season winter minimum temperatures or socioeconomic religious political factors How does one deconvolve 17th century cooling from Cromwell s puritanism 20 Jihye Yin says 22 Jun 2006 at 11 09 PM Could you please respond to some of the comments on the press conference as summarized e g here http motls blogspot com 2006 06 nas schizofrenic climate report html The NAS panelists said that the principal component method was incorrectly used in that context The climate before 1600 was almost entirely uncertain and even the level of confidence can t be quantified The MBH results were oversold by the community The divergence problem exists and does not want to go away The uncertainty and natural variations are larger than thought previously Are the NAS members wrong Are all of them paid by ExxonMobil as I believe Response Read the report itself not Lubos Motl s blog Motl s take on the report has almost no resemblance to what is in it What do you expect from somebody who describes himself as a reactionary physicist Unfortunately some un necessarily ambiguous wording at the press conference makes it all too easy for people like Motl to misrepresent the contents raypierre 21 Chuck Booth says 22 Jun 2006 at 11 40 PM Re 11 I can say with absolute certainty that it s warmer today where I live 90s than it was back in December when I was getting snowed on Can you provide some mathematical precision to that qualitative assessment 22 Leonard Evens says 23 Jun 2006 at 1 14 AM Re 11 We are getting off topic again In mathematics you can prove something and be certain it is correct subject of course to possible mistakes in the proof in the sense that the conclusion follows logically from the assumptions A model for this is Euclidean geometry which is as true now as it was over 2000 years ago But as a statement about the actual geomtry of the world we know it is false In science you are more concerned with conforming to observation and you may even in some cases accept arguments which don t stand up to the requirements of mathematical rigor as long as they make accurate predictions You sometimes do that also in applied mathematics I believe that is the distinction that Gavin was trying to make You can t expect the kind of certainty you find in pure mathematics in any science particularly a messy one like climatology where you have to bring together many different kinds of evidence That doesn t of course mean that anything goes There are rather severe restrictions on what can pass as an acceptable argument But it is not an axiomatic system 23 Bob Burnier says 23 Jun 2006 at 2 38 AM I have just begun to take a look at the scientific debate on global warming I am no climatologist but rather an individual with a doctorate in chemistry What I find interesting is the focus by everyone on the term warming and all this effort at looking at historical temperatures The relevant parameter to me is the amount of heat our global system has at any point in time If you add heat to an ice cube the temperature of the ice cube does not change The heat is used to melt the ice and during this process of melting the temperature stays constant This temperature is called the melting point or freezing point of the substance in this case water Once the ice has melted the temperature of the water will rise depending on the amount of heat entering the system the heat capacity of water etc So if the earth retains more heat because of rising greenhouse gases water temperatures may not rise signifcantly because the heat is used in melting ice If all the ice melts water temperatures will rise in accordance with the amoount of heat being absorbed and stored by the system oceans land and air From what I have seen we have lost a fair amount of glacial and perhaps polar ice over the last thirty years or so This means more to me than a debatable one degree rise in average ocean temperature over the last one hundred years If the ice goes temperature rise will be self evident Perhaps some of the scientific committees should add a few physical chemists to their panel discussions 24 Wolfgang Flamme says 23 Jun 2006 at 2 56 AM The National Academy scientists concluded that the Mann Bradley Hughes research from the late 1990s was likely to be true said John Mike Wallace an atmospheric sciences professor at the University of Washington and a panel member The conclusions from the 90s research are very close to being right and are supported by even more recent data Wallace said http www newsone ca hinesbergjournal stories index php action fullnews id 197149 No more funding no more research needed Just ask Wallace since he s the one knowing right from wrong Response Mike Wallace is one of the clearest thinkers in the field a National Academy member and author of dozens of highly influential papers Respect for his point of view though not mandatory is highly recommended He does not make such pronouncements lightly gavin 25 Paul Biggs says 23 Jun 2006 at 4 39 AM Please don t take my vineyard proxy post too seriously it was meant to be light hearted but it does indicate that Ledbury was particularly kind to the grape vine from the 13th century onwards until the end of the 17th century which would coincide with the maunder minimum The current UK warm period peaked in 1997 Armagh Observatory and 1999 Hadley CET in our two long temperature series I don t see 2006 beating those annual average temperatures but we ll have to wait and see what happens in future years Breaking the 11C barrier for an annual average would certainly be instrumentally unprecedented in the UK 26 pete best says 23 Jun 2006 at 5 52 AM The UK now has some 400 vinyards but as you can appreciate the best ones lie in the deep south of the UK and have indeed WON awards especially in the sparkling wine categories I have visited many of them and indeed the growing season appears to be around 1 month longer than it was in the year 1900 Indeed so popular has English Fizz become that the californians and the French Champagne makers are looking at buying land in the south of the UK in order to grow grapes and makes good fizz bubbly Anyway onto the subject at hand Fred Pearce in his book the Last generation devotes a chapter to this hockey stick proxy subject and states that the proxy data used has been suject to reanalysis and has been declared to be sufficiently statisticlly accurate that I thought that the subject has been laid to rest Indeed Realclimate has also made comment on this subject in relation to the climate skeptics and have also stated that independent reanalysis of the statistical data shows it to be accurate and correct within normal error thresholds Indeed the book even quotes Gavin at one point so I guess you guys at real climate know Fred Pearce 27 Barton Paul Levenson says 23 Jun 2006 at 7 08 AM I just ran across a paper from 1991 which seems to make a devastatingly impressive case that Solar activity has caused recent global warming Amazingly it s not by Soon and Baliunas Can anyone take a look at this and tell me where the mistakes if any lie I assume this has since been discredited but I don t know the details http www tmgnow com repository solar lassen1 html Response Devastating Try made up The figure only looks so good because the smoothing they use changes as you go along With 15 years more data and uniform data treatment the correlation disappears I would judge this the best example of researchers fooling themselves into finding what they wanted to find before they started Read Damon and Laut 2004 for the details and other examples gavin 28 Leonard Evens says 23 Jun 2006 at 9 33 AM Re 23 Perhaps a physical chemist just beginning to study the subject should do some more research before giving advice A good place to start would be the IPCC reports but much has happened since the last report There are variety of factors which lead to delays in warming one of which is the one he points to and those who do research in the area including the Real Climate scientists are well aware of them Response That s a little harsh A pointer to some of the existing work on heat content changes would be more constructive try Levitus et al 2001 and Hansen et al 2005 for instance gavin 29 Coby says 23 Jun 2006 at 10 40 AM Re 23 You have a reasonable point here and it is not one nobody else has thought of There is however good reason to focus on surface temperature and that is the simple fact that the surface is where we all live It is also where the vast majorty of the biosphere exists if we extend it into the the upper ocean You could also fundamentally alter the system simply by redistrubuting the heat no net change required So a total heat content metric is a good one but I would argue that the change in surface temperature is more appropriate for policy discussion and impact assessments Response Indeed it s a reasonable point and indeed it s already incorporated into calculations of climate change though not necessarily into public communication about the results The energy needed to melt ice whether sea ice or land ice is part of the thermal inertia of the system that slows the approach to equilibrium The major term in the thermal inertia is the time required to warm the deeper ocean So properly speaking the effect of added greenhouse gases shows up partly as warming and partly as melting and that warming shows up partly as surface warming and partly as deep ocean warming until the system reaches equilibrium With regard to the suggestion in the original post the basic calculations on the physics of planetary climate have rested on energy balance ever since Fourier s 1827 paper raypierre 30 Jean Luc P says 23 Jun 2006 at 11 08 AM Reply to Bob Burnier The fact is that exchange rate of heat are more a limitation at this scale than at your drinking glass scale so your interresting naive analysis of why temperature don t increase so much is maybe not very relevant because of that 31 esrc fan says 23 Jun 2006 at 1 20 PM In addition to the references given by Gavin regarding the heat content in the ocean Levitus has a paper in GRL Levitus 2005 on climate subsystems heat content Continental subsurface heat content has been addressed by Beltrami et al 2002 Beltrami 2002 and more recently in Beltrami et al 2005 32 Doug Percival says 23 Jun 2006 at 2 17 PM raypierre wrote in response to 15 However so far we haven t quite gotten to 400ppm CO2 but we ll eventually go to 700 or more without controls We haven t even seen the full warming effects of that 400ppm yet because it takes time for the ocean to warm up So the striking thing is that it has already gotten to the point that the recent warming stands out from the natural variability of the past thousand years or more despite the fact that so far we ve only experienced the barest beginnings of the warming That s not just striking It ought to be alarming It is not only alarming it is outright terrifying And that along with the self reinforcing feedbacks that the barest beginnings of the warming are already apparently triggering increased heat absorption by ice free arctic oceans release of carbon and methane from warming soils etc is what makes me skeptical of the view expressed by Al Gore and others that we still have some ten years in which to prevent irreversible catastrophic runaway warming and not only climate change but a global ecological collapse I find it hard to see how we have not already passed the point of no return 33 Tom McKissic says 23 Jun 2006 at 5 58 PM I do not understand why it is not rational to question models and trends which are being used to predict unkown future conditions but it remains perfectly acceptable to dismiss past 10 000 year B P proxy data which may conflict with present models I realize proxy data is limited at this time particulary for the southern hemisphere but the existing data should not be ignored just to make recent history models stand up I welcome the day when sufficient data has been collected so a confident model can be created which when fed data up to a past point can accurately predict past temperatures Response What is being ignored And what do you feel is inconsistent with the models Simulations for mid Holocene conditions driven mainly by orbital forcing do a good job of matching the obs gavin 34 Tom McKissic says 23 Jun 2006 at 8 19 PM Your response supports my point Certain simulations based on certain conditions match certain observations but a golden rule has not yet been created The models driven mainly by orbital forcing are not the models currently being touted as future predictors of climate in most cases solar influence is being ruled inconsequential for current conditions So far in order to match accepted historic and prehistoric observations something has to be ignored The stakes are high for supporting either side of the global warming issue Regardless of the point you are arguing it is irresponsible to dismiss alternate views when there are still so many unknowns Remember it was once the scientific consensus the sun orbited the earth the world was flat the sound barrier was unbreakable I agree with Williams response above fund more research for creating more accurate models Who knows we may find we should be heading colder and the only thing maintaining temperature is Co2 Response You have it completely wrong The state of the art models used for the 20th Century and future simulations are exactly the same ones that are being tested using paleo climate conditions Look up PMIP II for instance At different times in the past different things were going on and some are more important on some timescales than others There is no golden rule Instead there is a complex system that can be pushed around by multiple different forces including orbital variations solar variability the opening of ocean gateways volcanoes and yes greenhouse gases For the current situation orbital forcing is very small and so doesn t play much of a role solar variation is as far as we can tell a minor player GHGs are a big factor and so are aerosols ozone volcanoes land use are all also minor but necessary Why do you think things are being ignored All of these things are tested to see if they are important and the ones that are are kept in gavin 35 Eli Rabett says 23 Jun 2006 at 9 43 PM Paul Biggs need not apologize Pfister s record of monthly precipitation in Central Europe 1525 1979 does include information from diaries recording the time when grape vines blossemed and the grapes were ripe 36 Tom McKissic says 23 Jun 2006 at 9 48 PM Your use of the absolute completely emphasizes my argument that no side should be closed and imflamatory Ignore my use of term golden rule and acknowledge YES there is a mathematical equivalent for all the complex factors driving climate An accurate model has just not yet been created Your statement All of these things are tested to see if they are important and the ones that are are kept in implies some things are left out All influences if found to be important at any time have the potential to be important in the future There are way to many unkown interactions in the complex system to leave out certain influences It should be everyones goal to keep updating and improving models regardless of the findings My concern is the tendancy of those with extreme support of current global warming understanding as an absolute to villanize others with legitimate questions realizing there are those types on both sides but pro warming has the stage right now I agree there is currently work being done to make a more comprehensive model which address past and present conditions in order to accurately predict future changes but disagree there is a working model with published results clearly matching early and current observations It is a frustrating data search when the vast majority of supporting information focuses on the last 1000 years and contrary information focuses on the paleo I like many others am only asking for a link before jumping on the bandwagon of industrial reform With proper support and open minded researchers or at least the teaming of opposites to tackle the endeavor this should not substantially delay any needed social change and could actually result in faster change if universally supported Response Oh please If you would get off your high horse for a second and you would see that testing against paleo data and putting in of new physics is what we actually do all the time check out my own publication list for instance you ll find solar and volcanic and mid Holocene and LGM and PETM and Cretaceous gavin 37 Don Baccus says 24 Jun 2006 at 9 29 AM An accurate model has just not yet been created Your statement All of these things are tested to see if they are important and the ones that are are kept in implies some things are left out All influences if found to be important at any time have the potential to be important in the future If rational simplifications of mathematical models disturb you so may I humbly suggest you never step foot upon a Boeing 787 38 Tom McKissic says 24 Jun 2006 at 10 06 AM Thanks for the personal attack Models are being tested putting in and taking out of factors and many are good at matching certain timescales but nothing has been found to model accurately accross all timescales with known information Yet many are taking data produced and circulating it as fact when even the persons generating the data referencing probabilities All I m asking is the same effort be put into research as is currently put into marketing certain findings and suggested responses 39 Carl Christensen says 24 Jun 2006 at 10 52 AM Re 36 there is the Millenium Project now that will have various modelling groups do the last millenium Most groups do hindcasts over a period ranging from 50 to a few hundred years i e covered by the high probability MBH98 area and HadCRU etc For example my own project is currently doing a 1920 2000 hindcast and a 2000 2080 forecast in a large ensemble using the HadCM3 model to quantify uncertainties in the model try a large range of parameters etc You really need to look at the actual literature work done rather than jump to false conclusions 40 Tom McKissic says 24 Jun 2006 at 10 53 AM Simplifications are fine if they return results that match observed occurences and not just for certain conditions or timeframes Boeing models work just as well at 500 feet as they do at 30 000 feet over all temperature ranges and all forces if they didn t planes would fall out of the sky

    Original URL path: http://www.realclimate.org/index.php/archives/2006/06/national-academies-synthesis-report/ (2016-02-13)
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