Recent Comments

Prev  2397  2398  2399  2400  2401  2402  2403  2404  2405  2406  2407  2408  2409  2410  2411  2412  Next

Comments 120201 to 120250:

120201. ktam at 08:23 AM on 1 May 2010
        Why are there fewer weather stations and what's the effect?
        Berényi Since you consider what Tamino has done is meaningless. Have you taken it up with Tamino. Since Zeke, Nick Stokes, Jeff Id, CCC seem to have replicated much of what Tamino has done plus one of them has extended the analysis to produce a global land/ocean temperature reconstruction have you taken this issue up with those who have the tools and experience/background to interpret your results. http://rankexploits.com/musings/2010/comparing-global-land-temperature-reconstructions/ http://rankexploits.com/musings/2010/comparing-global-land-temperature-reconstructions/ http://moyhu.blogspot.com/2010/04/incorporating-sst-and-landocean-models.html http://clearclimatecode.org/ http://residualanalysis.blogspot.com/2010/03/ghcn-processor-11.html http://tamino.wordpress.com/2010/03/05/global-update/ It will be interesting to see the discussion where those who have the statistical background and knowledge of the temperature data to interpret your results. Kevin
120202. suibhne at 07:46 AM on 1 May 2010
        Where is global warming going?
        doug_bostrom By longwave em radiation
120203. RSVP at 07:10 AM on 1 May 2010
        Skeptical Science talk at University of Qld on May 7
        John Russel "too fast for most plants and animals to move" Humans were nomads way before they settled down and fenced in their properties and animals migrated as needed (now they get squashed on highways). Point is, the only problem with global warming is that the status quo is finally threatening itself. Nature is equipped for global warming. Modern civilization...that is another issue.
120204. Phila at 06:38 AM on 1 May 2010
        Common graphical tricks and the Medieval Warm Period
        #48 Mike "It is not the number of reports that matter, it is the quality and impartiality of those reports and so long as we continue to read reports that are clearly biased in that they fail to acknowledge simple things like urban heating, the poor siting of sensors or simple statistical facts like the cooling this century or that if there were warming it would have considerable benefits by reducing the number of cold related deaths in Norther latitudes." Each of these points has not only been "acknowledged," but addressed. Repeatedly. On urban heating, see Are surface records reliable?. On the cooling this century, see Is global warming still happening?. On cold-related deaths, see here.
120205. e at 06:34 AM on 1 May 2010
        Common graphical tricks and the Medieval Warm Period
        Mike, > may I ask you how many times a politician has to tell you they saved the planet from global economic collapse for you to believe them? If they have hundreds of rigorous scientific studies and empirical data to back their claim, then once will suffice. > Repetition of the same assertions which are not believed do not and should not increase belief in those assertions. Scientific studies are not assertions, they are examinations of empirical reality using the most objective and effective technique available to humanity: the scientific method. Ironically, a lot of "skeptic" arguments are nothing more than a repetition of assertions, your post being a great example. If you have some specific complaints or questions about the science, please review the list of skeptic arguments on this site, and place your comments under the appropriate post (if you are truly interested in the answers, you should probably read the post as well). > science is inherently sceptical and requires those making assertions to prove what the say; it does not require the sceptic to disprove it! Hence the multitude scientific studies that overwhelmingly support AGW.
120206. Phila at 06:24 AM on 1 May 2010
        Common graphical tricks and the Medieval Warm Period
        #45 Jeff Freymueller "I'm not saying that there isn't or can't be legitimate criticism as well, but my assessment is that most of the "skeptic" criticisms of Mann are based on nonsense (or character assassination)" Well said. Focusing on Mann's reaction to criticism, as some skeptics are wont to do, amounts to little more than ad hominem. How he responds to attacks on his work really has no bearing on the quality or reproducibility of that work.
120207. Berényi Péter at 06:23 AM on 1 May 2010
        Why are there fewer weather stations and what's the effect?
        Posted by John Cook at 15:28 PM the dropped weather stations actually show a greater warming trend than the kept weather stations Interesting. However, it deserves some checking, doesn't it? So I have fetched current GHCN data form the GISS Temperature site. Raw data are in v2.mean.Z. The readme file is also handy. I have lumped together data according to WMO station number and selected 610 stations that have reasonable coverage for the last forty years (from April 1970 to March 2010). Then I have calculated average temperature trend on this set for each station and for the entire set on the first and second twenty year periods (April 1970 - March 1990 & April 1990 - March 2010 respectively). The warming found is huge and accelerating. It is 0.0239 °C/year for the first two decades and 0.0297 °C/year for the rest on this particular set. Then I have divided the set of stations into two equal subsets. Subset A contains those stations that have the least trend during the first two decades, subset B the rest. Average warming for A in this period is 0.0018 °C/year while it is 0.0461 °C/year for B in this period. And here comes the surprise. For the last two decades the trend for A is 0.0359 °C/year while for B it is 0.0235 °C/year. It is really odd. Let me rephrase it. If stations with the largest warming trend at the beginning were dropped, the rest would show more warming on average, not less. Therefore what Tamino did, is meaningless and you also have to reconsider your points. The vague description of procedure followed is intentional. I would like others to repeat it, with slightly different assumptions, just to see how robust it is. Neither have I applied any adjustments, although it would be easy to repeat it with v2.mean_adj. The result begs for an explanation. My bet would be it is UHI. The local warming influence of human presence is roughly proportional to the logarithm of population density. If population growth is slower than exponential, the UHI effect increases in a sub-linear fashion. If we keep throwing out stations with large warming, the rest is getting more rural with larger warming potential. Indeed, in set B there are considerably more stations flagged rural than in set A. the reason for the "dropped" weather stations is merely the result of stations no longer actively recording temperature data John, this statement is not an adequate description of reality. Find another explanation, please. Weather Underground manages somehow to collect several reports per day for the overwhelming majority of stations dropped from GHCN in 1990 and also for those USHCN stations dropped in 2005. I have started a script that pulls down the daily data from that site. Unfortunately it takes time, for the site is protected against DoS attacks, therefore large pauses are needed between accesses (otherwise access is rejected). They have station histories going back to decades, in some cases as far back as the fifties. With these the hypothesis above can be tested. As soon as I'll have enough data, I will report back.
120208. Doug Bostrom at 05:50 AM on 1 May 2010
        Common graphical tricks and the Medieval Warm Period
        Mike, that was 6 paragraphs and 470 words without a single specific complaint about science or for that matter data visualizations. Not that anybody's counting, but you may have set a record... ;-)
120209. Doug Bostrom at 05:44 AM on 1 May 2010
        Where is global warming going?
        Suibhne, perhaps I should ask the question a different way. Does energy leave planet Earth? If so, how?
120210. Mike Haseler at 05:03 AM on 1 May 2010
        Common graphical tricks and the Medieval Warm Period
        JMurphy "Just how many studies would be enough to satisfy the so-called skeptics ?" JMurphy, you seem to fundamentally misunderstand the sceptical position. To answer your point, may I ask you how many times a politician has to tell you they saved the planet from global economic collapse for you to believe them? Repetition of the same assertions which are not believed do not and should not increase belief in those assertions. Moreover, science is on the side of the sceptic, because science is inherently sceptical and requires those making assertions to prove what the say; it does not require the sceptic to disprove it! But at a more systemic level, the climate community have systematically failed to address many of the concerns raised by the scientifically sceptical. Rather than accepting reasonable criticisms of the problems of the modelling, "unknown unknowns" and most importantly the abysmal temperature record (my speciality) there has instead been a nasty smear campaign against anyone who dared to be scientifically sceptical. Far from making us believe you are “scientists” this smear campaign smacks of blatant political propaganda and unfortunately anyone no matter how political they are in the subject, is tarred with the same brush. Moreover, the climate community have hardly done themselves any favours by their response to the behaviour revealed in the climategate emails. As some have said such things can go on in any academic field, but whilst a firm rebuke from the discipline would have given us some confidence that the behaviour in the emails was not deemed acceptable, the silence and (from our view) a whitewash of inquiries has shown to the sceptics what we now see as a community of academics with absolutely no willingness to bring the standards of their discipline up to the standards the sceptics believe is appropriate for such a high profile world-wide important and hugely costly area of research. So, much of the sceptical response to the climate community is self inflicted by that community. Most sceptics are not heartless animals. We are mostly people with real life experience or real life situations, where we have seen how people can be misled by statistics and a "bee in their bonnet" to come to the wrong conclusion. It is not the number of reports that matter, it is the quality and impartiality of those reports and so long as we continue to read reports that are clearly biased in that they fail to acknowledge simple things like urban heating, the poor siting of sensors or simple statistical facts like the cooling this century or that if there were warming it would have considerable benefits by reducing the number of cold related deaths in Norther latitudes.... basically so long as we can see the reports are obviously biased, it won't matter how many are produced because our training tells us that it is not scientifically appropriate to “believe” them.
120211. suibhne at 04:52 AM on 1 May 2010
        Where is global warming going?
        doug_bostrom The planet can heat up and cool down over geological periods. Heating up means gaining internal energy. Cooling down means losing internal energy.
120212. Jacob Bock Axelsen at 03:53 AM on 1 May 2010
        Are we too stupid?
        embb I forgot to mention. I am contractually obliged to divulge science to the public. How do you imagine tit-for-tat working among states? You defect to fulfill your emission goals, we punish through trade restrictions, UN resolutions, treaties that disfavor your interests, making the IMF put conditions to loans during economic downturns etc. Reciprocity. It gets better. Axelrod points out that a small cluster of players using tit-for-tat may completely eliminate all the defectors (and keep them from reemerging). Quite interesting. Lots of recent research points in that direction incl. the references in my post. Have you read any of them? I can provide a lot more. In terms of environment, no gain at all. There is no environmental gain from preventing climate change? Energy security could be a gain but it is almost accidental - there are cheaper and more efficient ways to achieve energy security. What are those ways? And compared to what, exactly? Do the cheaper ways destroy the planet? I meant security in terms of not being dependent on imported oil, what do you mean by 'energy security'? There is a state above the Californian companies. So your example does not answer my question. The fig tree/fig wasp symbiosis shows that tit-for-tat works without executive power. Isn't it amazing how nature always beats humans in ingenuity? I did not see any acceptable solution Let me reiterate: should anything be done to prevent climate change?
120213. chris at 03:39 AM on 1 May 2010
        Skeptical Science talk at University of Qld on May 7
        "Qld"? Surely "Qnsld"...
120214. Marcel Bökstedt at 03:20 AM on 1 May 2010
        Common graphical tricks and the Medieval Warm Period
        HumanityRules> New data on the middle age climate arrive all the time, and I don't think that this case is closed yet. But the paper by Mann etc. seems to be a strong paper, even if it does not seem to take all available published proxies into account. I can't see that the paper about South America by Neukom et al. that you linked to contradicts the Mann paper, they claim that the summers in SA were "mostly above the 1901–1995 climatology". They do not claim that they were as warm as now. The paper by Oppo et al. is about the tropical waters around Indonesia, so it's not really southern hemisphere. It also has temperatures around 1200 well below present temperatures, and also estimated temperatures below the estimated North Hemisphere average (figure 3). So I can't see that paper as contradicting Mann's paper either. I'm sure you have read those two papers closer than I have. If I'm missing something, please explain.
120215. ktam at 03:19 AM on 1 May 2010
        Common graphical tricks and the Medieval Warm Period
        I have also recently blogged on why i think the Hockey Stick isn't broken: The Hockey Stick is Accurate
120216. Jeff Freymueller at 02:23 AM on 1 May 2010
        Common graphical tricks and the Medieval Warm Period
        #35 Humanity Rules, I think it would be a surprise if Mann was NOT defensive, given the politically motivated assault that has been made on him personally and on his work. I think nautilus_mr has it right in #36 about the intuitive power of the hockey stick graph, which is why so much is made in many skeptical camps about that one result. Hint: he's not being attacked because he reacts defensively, but because some don't like the conclusions of his work. Whether ego or other personality factors contribute to his reaction to criticism, I really don't know because I've never met him and only had one second-hand interaction with him. I have my own guesses but it's just speculation. I haven't read all of the relevant papers on the paleoreconstruction topic, but the papers I have read demonstrate exactly what you call for: a drive to improve the science. Criticisms are made and countered in the literature, on this topic as well as many others. What is different on this topic is that there is a firestorm of criticism (and noise and distortion) outside of science because of the political implications of the results. I'm not saying that there isn't or can't be legitimate criticism as well, but my assessment is that most of the "skeptic" criticisms of Mann are based on nonsense (or character assassination) or on nitpicking that has had little impact on any conclusion (the decade claim I mentioned before being the one conclusion that didn't hold up). Otherwise, more than a decade of subsequent work and a lot more data has not altered the fundamental conclusions. The last paragraph of #36 is also on the money as far using science to address issues that are also politically important. On issues of political importance, we know and expect that people with financial interests will hire lobbyists and mouthpieces whose job is to say anything, regardless of facts, to advance the interests of their clients. Scientists have to be careful to stick to presenting the results and implications of their scientific work, but if we don't say what our results are and what our science tells us about potential options and consequences, then I think we would be doing a disservice to the people who ultimately pay the bills for research.
120217. Doug Bostrom at 02:18 AM on 1 May 2010
        Where is global warming going?
        Suibhne, you don't believe in radiative equilibrium? Can you describe how the planet sheds energy, or is it being stored somewhere inside the globe?
120218. Bob Lacatena at 02:08 AM on 1 May 2010
        Tracking the energy from global warming
        Just a thought... there is another possibility for where some of the heat could be hiding. Greenland and Antarctic ice melt is, I assume, estimated through the gravity measurements of the GRACE satellite, but that only measures mass change, i.e. ice that melts and then runs off into the ocean (I presume). Suppose the degree of ice melt is much greater than currently assumed, but large amounts of the melt sink into crevasses or seep down in other ways without an opportunity to escape? This is particularly likely in Greenland, where I believe there is a large basin below sea level that would ultimately trap melt water. Based on watching snow melt in my yard (probably not a good model for places like Greenland and Antarctica, where it is densely packed ice instead of loosely packed snow, but...) a lot of the melt water spreads through the depth of the snow and eventually seeps into the ground or runs off from underneath, where it can find an outlet like the edge of the plowed street. This also seems to melt a lot of snow "from the inside" away from the sun by transporting the heat downward in a form of convection. What might happen in Greenland or Antarctica, with kilometers of depth to penetrate before some of the water is redirected outward "toward the street"? Could large crevasses/channels/tunnels be accumulating the water, and melting and growing from the inside from the heat and pressure? I don't know the numbers, so I don't know how much melt would account for what percentage of the missing heat, but it's a scary idea, both in the thought that ice could be melting faster than we think, and that there could be sudden sea level rise events unleashed if some of that reservoir of trapped melt water is unexpectedly released.
120219. Philippe Chantreau at 01:56 AM on 1 May 2010
        Common graphical tricks and the Medieval Warm Period
        Thingadonta @ post 27. The "skeptic" position as you define it seems to be total nonsense. Why would the climate be more sensitive to a radiative forcing than another? How could the Earth/atmosphere system react differently to an energy imbalance according to the origin of that imbalance? How does the Earth "know" to react little from the extra w/sq.m coming from GHG but lots to that of solar irradiance? It makes no sense. What possioble physical processes could be at work in such discrimination? Where does the extra energy go for "low sensitivity" forcings? Are you sure that this is what "skeptics" argue? Is that what you believe?
120220. Philippe Chantreau at 01:41 AM on 1 May 2010
        Skeptical Science talk at University of Qld on May 7
        Portland, OR being a rather distant suburb of Brisbane, I won't be able to attend but I wish you the best John. Thanks for walking the talk :-)
120221. HumanityRules at 01:33 AM on 1 May 2010
        Common graphical tricks and the Medieval Warm Period
        40.MarkR Mann in 2009 produced a paper that purported to show that the MWP was a regional occurence (essentially NH). You can read John's post about it here. Was there a Medieval Warm Period? That paper uses 6 SH series that stretch back to the MWP that show a lack of warming in the SH. The papers I link to in #28 include 5 SH series that show greater temperature variability than Mann and show the MWP as warm as the present. The Mann 2009 paper was uncritically presented on this website as proof of a regional MWP. So is 6 a "significant #s of proxies" while 5 is insignificant?
120222. suibhne at 01:30 AM on 1 May 2010
        Where is global warming going?
        KR ......G&T, on the other hand, seem to claim that radiative heating doesn't exist at all, which would overturn ~220 years of scientific consensus, contradicts _all_ the experimental evidence and measurements, and is certainly not proven by their collection of errors, logical fallacies, and outright junk........ What makes you think that G&T "claim that radiative heating doesn't exist at all" Quote a page number or such like.
120223. suibhne at 01:25 AM on 1 May 2010
        Where is global warming going?
        KR I think you must have missed recent post in which Kevin Trenberth frankly admitted that he couldn't account for what he called the "missing heat" and further worried that unless it is found "it could come back and haunt us". I on the other hand like Richard Lindzen do not believe in radiative equilibrium hence the post above. The very simple model excluded geothermal and gravitational effects such as tidal flows etc which would only detract from the focus on these points. I have exaggerated many physical effects to make radiative equilibrium as big a problem as I can make it. If you can think of any further reasonable inflation of the problem please let me know and I will include it. Including non related phenomena only make the case for human induced CO2 as a major problem much weaker. Reasonable conductivity given the time scale of 1000 years should enable the one degree rise in temperature.
120224. shdwsnlite at 01:03 AM on 1 May 2010
        Skeptical Science talk at University of Qld on May 7
        Any chance of the event being recorded for those of us not in that part of the world?
        Response: I haven't discussed it with the UQCfC. Honestly, I'm not a big fan of the idea as I don't particularly like the sound of my own voice but I'll ask. At the very least, I can always post the slideshow on the webesite.
120225. KR at 00:14 AM on 1 May 2010
        Where is global warming going?
        Hmm... I'm reminded of a joke about a farmer (with milk production problems) asking a physicist for ideas, leading to a discussion of "spherical cows". The Earth's core is already pretty warm (think lava) from radioactivity and residual heat; it would be interesting although irrelevant to calculate how long before we melted once we stopped losing radiative energy to space. It was my understanding that Trenberth has refined his data and estimates, based on temperature variation and a fourth-power rule for heat radiation (to use the Max Planck term). That's science - always improving your results with further study. G&T, on the other hand, seem to claim that radiative heating doesn't exist at all, which would overturn ~220 years of scientific consensus, contradicts _all_ the experimental evidence and measurements, and is certainly not proven by their collection of errors, logical fallacies, and outright junk. It reminds me somewhat of the Transformative Hermeneutics of Quantum Gravity paper, 'tho with less overall humor. And once again, short term variations are quite large - that doesn't change the facts about long term temperature shifts of the center-point around which those variations are based.
120226. Jonathan E Markham at 23:37 PM on 30 April 2010
        Common graphical tricks and the Medieval Warm Period
        I don't think it's valid to compare the 10yr average now with the 50yr average from 800yrs ago, you need to plot the 10yr averages for the whole graph or, inconvenient as it may be, stick with the current 50yr average.
120227. John Russell at 23:04 PM on 30 April 2010
        Skeptical Science talk at University of Qld on May 7
        RSVP: The question John asks -- " (if) ...there's any empirical evidence that humans are causing global warming?" -- is perfectly valid. That question does not exclude the possibility that there are underlying natural variations of temperature that would have occurred anyway. Any human causes of warming clearly modify natural events, either worsening or mitigating their effects. If you read the relevant sections of this site you'll find that a critically-important point is that the human-induced element of the current global warming is resulting in change at an unprecedented rate -- too fast for most plants and animals to move, adapt or evolve to accommodate (and I include humans). And THAT'S the rub.
120228. JMurphy at 22:35 PM on 30 April 2010
        Common graphical tricks and the Medieval Warm Period
        Just how many studies would be enough to satisfy the so-called skeptics ? NOAA have published the data for nearly 100 reconstructions, and shown them individually here, along with visualisations, using lots of proxy data types Will any number of studies satisfy those who want to keep believing in a 'broken' hockey-stick or a 'lying, cheating, etc.' Mann ? I don't think so.
120229. sleepership at 20:44 PM on 30 April 2010
        It's cooling
        April has been record breaking in Connecticut for warm temperatures. Today it will be 77 degrees- after a month that has been 6.7 degrees above normal. Tomorrow 85 degrees, and Sunday 90. Of course this is day to day weather- however, warming of this magnitude after years of milder winters and earlier springs is troubling to say the least. The climate models always predicted that after 2010 we would begin to see record warming-is this 'that' beginning?
120230. Alexandre at 20:39 PM on 30 April 2010
        Skeptical Science talk at University of Qld on May 7
        It's great to hear that, John. Let us know if the slideshow or video or audio is available afterwards.
120231. ktam at 20:03 PM on 30 April 2010
        Why are there fewer weather stations and what's the effect?
        Another issue is the claim that the temperature adjustments at various weather stations are the reason for the warming trend, once again this is based on anecdotal evidence. What demonstrates this claim to be false is a different graph from the Zeke Hausfather page already referred to in this piece. In that plot they compare the warming trend various forms of the raw data against GISS Temp. GISS Temp shows the weakest warming trend of them all demonstrating that the adjustments are reducing the measured trend not increasing it. From Zeke Hausfather at rankexploits
120232. ktam at 19:16 PM on 30 April 2010
        Why are there fewer weather stations and what's the effect?
        I think an important bit that you have missed out is the analysis of the surfacestations.org data by Menne et al. I refer to it in a rather provocatively titled blog post here: Nasa underestimates global warming"
120233. MarkR at 18:56 PM on 30 April 2010
        Common graphical tricks and the Medieval Warm Period
        #28 HumanityRules: My main criticisms of using graphs like that (there were many examples on CO2science, I might put them up in another post) are that they often concentrate on one region or that they cut off post 1950. Now, that isn't necessarily a problem with the science. Sometimes proxies don't go after 1950 for whatever reason. But to claim that this shows the MWP was warmer is just wrong. You need alternative evidence to do that & so far I'm not aware of any reconstructions of hemispheric or global means from significant #s of proxies that show that.
120234. Argus at 18:45 PM on 30 April 2010
        A visual depiction of how much ice Greenland is losing
        Phila (#71), your comment to #61-gallopingcamel : How could sea levels continue to rise if the amount of CO2 in the atmosphere was hypothetically reduced by a factor of 2 (to 194 ppm). If the CO2 content in the atmosphere is so essential for the increasing temperatures we observe (and the rising sea levels), I would rather expect the earth to rapidly cool off, and the sea levels to decrease as a consequence.
120235. Marcel Bökstedt at 18:42 PM on 30 April 2010
        Common graphical tricks and the Medieval Warm Period
        thingadonta> OK, so according to you, the (a?) skeptic position is that there is some external forcing that caused both the medieval warm period and the present warm period. Can this be made more precise? I would like to know what mechanism is supposed to be responsible. The linearity probably comes from the assumption that effects are differentiable functions of causes. This is a very common assumption, and by definition it means that if the cause is "sufficiently small", then the effect depends linearily on the cause. Your example with the volcanoes is not relevant here, because you are talking about large effects. There is a catch of course, namely whether the causes really are "sufficiently small". As for climate sensitivity varying with the forcing, I think that we first have to agree on the definition on "climate sensitivity". The IPCC is guilty of confusing this issue, as discussed in the first 15 lines of wikipedia's article on climate sensitivity . But lets go with their latest definition. According to this, climate sensitivity is the reaction of the system of an increase in temperature. That is, suppose that a forcing would cause a temperature rise of RF if there were no feedbacks. We would like to know how big the increase would be if we include the feedbacks. The climate sensitivity provided by the feedbacks would conspire to give a temnperature rise of l * RF, where the number l is the climate sensitivity. So in this definition of climate sensitivity, it does not depend on any particular forcing. It is determined by the reaction of the system to an increase in temperature. Maybe I'm missing some point here.
120236. Riccardo at 18:22 PM on 30 April 2010
        Skeptical Science talk at University of Qld on May 7
        ESVP, if you want to anticipate John's answers to your questions take a quick tour of this site, you'll find them and a lot more.
120237. Riccardo at 18:18 PM on 30 April 2010
        Common graphical tricks and the Medieval Warm Period
        Semczyszak, even if Professor Boryczka is right it would not be smart to lower our chances of a safe landing after the pending climate crises. I mean, if there will be a natural trend of, say, 2 °C for the next century it surely won't help to add 3 more degrees ourselves. Or should we be so nihilist to say we're doomed anyways and we should not even try to fight?
120238. Arkadiusz Semczyszak at 17:23 PM on 30 April 2010
        Common graphical tricks and the Medieval Warm Period
        "... like cherry picking 100 Chinese companies that are having bad results to "prove" that Chinese economy is not growing. ..." - Is sophistry The existence of these "100 Chinese companies" however, proves that the "Chinese economy ..." not everything" is in order ... Incorrect interpretation - the use of cherry picking theory; is "a nightmare" discussion about climate ... "... the *rate* of change & the presence or absence of forcings to explain the previous warming events ..." Small "* rate * of change" in the earlier research (MWP) showed (in large part) of using a wavelet "old style" - excessive "smoothing" reconstructions (especially multi-proxies). About this repeatedly, even by Tamino. "... forcings ..." Polish climatologist of the our greatest University (Cracow), Professor Boryczka, forecasting solar activity and the NAO, believes that awaits us, in the XXI century (circa 2070-2100), a strong natural warming (the imposition of the cycles of 100 and 180 years - I would add Millennium x 3) - greater than in the MWP - MWA and CWP-CWA.
120239. RSVP at 17:16 PM on 30 April 2010
        Skeptical Science talk at University of Qld on May 7
        Are humans causing global warming? (I contend that this is a very loaded question. Here's why...) In order to answer that question, you need to break it down a little. What would climate be doing right now if there were no humans at all? would there be... A: warming anyway? B: a static condition? (and if so, for how long?) C: a cooling trend? To ask if humans are "causing" global warming only makes sense when you know what the trend would be for Nature alone without a human presence. For case A, humans would only therefore be contributing to warming. (And then the question would be "to what extent?".) If case C, humans could actually be detaining an impending iceage, or may have even reversed the trend. And a little more... The question is not, "Have humans caused global warming?", or "have humans touched off global warming?" When you ask if "humans are causing global warming" it seem to imply that the moment they stop activities, things will turn back to "normal".
120240. nautilus_mr at 16:45 PM on 30 April 2010
        Common graphical tricks and the Medieval Warm Period
        It is a challenge to stay clear-eyed about the Hockey Stick, because it has been such an iconic image and therefore of tremendous political importance. It has been used by the IPCC, Al Gore and others, precisely because it is so much more effective a communication tool than virtually any other illustration. It is certainly the image that got me tuned into the global warming problem -and I bet that is also true of many readers of this site. It is also no accident that the earliest attacks from AGW deniers were against the hockey stick and often Manne personally. The focus of AGW deniers is to score political wins; they use the language of science, because in this culture it adds gravitas, but their main targets are always the stuff laypeople can easily understand. People reasonably acquainted with the science know the various studies that comprise the hockey stick are only a small part of our overall understanding of climate change. Politically, however, it would be a massive coup for the deniers' camp if they could tear it down. The hockey stick has been given a political importance far beyond its scientific importance. So far as I can humbly tell, it has also yet to be proven wrong. But that could change, and we must always take care not to argue for a scientific theory because of the political consequences of it being incorrect-leave that to the Moncktons and Plimers of this world.
120241. James Wight at 15:24 PM on 30 April 2010
        Skeptical Science Housekeeping: flags, printable versions, icons and links... lots of links
        For some reason, neutral links aren't showing up on the resource pages.
        Response: The reason was because I hadn't programmed it to show neutral links yet. I've just remedied that and while I was in there tinkering with the code, I added a feature I've been wanting myself for a while - a "peer-reviewed" link so while you're in there looking at links for a particular argument, you can select to narrow it down to purely peer-reviewed papers.
        
120242. HumanityRules at 15:23 PM on 30 April 2010
        Common graphical tricks and the Medieval Warm Period
        34.Marcus Would "the contrarians" include Phil Jones (of CRU fame) who co-authored two of the papers I linked to in #28? 31.Jeff Freymueller I agree with what you say except I still think you can't ignore the political interference in this subject on both sides of the argument. It's what takes it from an interesting scientific problem to a controversy. Given you recognise the limitations and problems with the science why do you think Mann et al are so defensive about critisism? I'm aware of egos but a drive should be to improve the science and that partly comes through critical analysis.
120243. Bern at 14:48 PM on 30 April 2010
        Skeptical Science talk at University of Qld on May 7
        @MattJ: heh... no, it's purely descriptive, because it's a knoll which is, well, grassy... (i.e. nowhere to hide) There's also a Conifer Knoll on the other side of the uni, which may be well lit these days with the multi-storey car park right next to it, but back in the early 90s it was a pretty dark & spooky place at night, despite being in the middle of a well-lit campus. Unfortunately my calendar for next Friday is already rather full - not sure how I'm going to fit in work, let alone a trip to UQ at lunchtime... :-(
120244. Jeff Freymueller at 14:46 PM on 30 April 2010
        Skeptical Science talk at University of Qld on May 7
        As long as John is not being shot at from the "Grassy Knoll", that will be OK.
120245. Marcus at 14:46 PM on 30 April 2010
        Common graphical tricks and the Medieval Warm Period
        Even if the contrarians could prove-definitively-that the absolute temperature anomaly was higher in the MWP than today, there are still other issues to consider-namely the *rate* of change & the presence or absence of forcings to explain the previous warming events. Take a look at all the MWP reconstructions-even those produced by contrarians-& you see that it was a multi-century event (300-600 years from trough to peak, depending on which graph you look at). By contrast, we're seeing an almost identical magnitude of warming in the 20th century in the space of merely 50 years-a massive difference! The other point is that a look at proxies for Total Solar Irradiance during the MWP show a strong upward trend during that period, wheras the TSI for the last 30 years has been on a slight downward trend. So over the last 60 years we've seen an unprecedented *rate* of warming, without the forcings that characterised past warming events!
120246. barry1487 at 14:38 PM on 30 April 2010
        Why are there fewer weather stations and what's the effect?
        Seems to me that data collection of this type would be the perfect next step for surfacestations.org. It would be good outreach from NOAA to skeptics and make a fine and logical contribution for critics of the temperature record, obviating post-hoc auditing. Thinking about it, it's a pretty obvious marriage.
120247. Bernard Leikind at 14:19 PM on 30 April 2010
        Common graphical tricks and the Medieval Warm Period
        I believe that you are missing the word "not" in this sentence. They are showing you that the last decade was warmer than any 50 year period on the graph including the MWP. You need not post my comment, after correcting your sentence. Excellent, clear, informative post.
120248. Jeff Freymueller at 13:40 PM on 30 April 2010
        Common graphical tricks and the Medieval Warm Period
        #26 chriscanaris, in your comment you seem to be mixing up a couple of very different things. The data may permit a wide range of reconstructions, but that does not mean "anything goes", and does not mean that picking the average or most likely reconstruction is "cherry-picking". Maybe you need to look up the term! In any case, if you look at the reconstructions in scientific papers (and the recent IPCC reports) they come with error bars or shaded error regions, which show you how precise the estimates are. Presenting the best estimate, with a description of how you got it and its error bars, is very, very far from cherry-picking.
120249. Jeff Freymueller at 13:34 PM on 30 April 2010
        Common graphical tricks and the Medieval Warm Period
        #28, HumanityRules, it is a bit misleading to say the main criticism is that they end the graphs too early. Ending the graphs too early in order to make a misleading or false impression using those graphs seems more like it. What you describe as a "political statement" can be rephrased slightly as a legitimate scientific question: "Is today’s global average temperature, averaged over a few decades, higher than any such time period in the past 2000 years?" Once you specify the averaging time and the total time span, that is a question that has a yes/no answer. Our best estimate of the answer may or may not be yes/no at this time, but the question is objective and not political. Mann made the claim in 1998 that it was, with an averaging time of a decade, and this was the only scientific conclusion of his 1998 paper that has not stood up. He was wrong not because of any error specifically in his work, but because the uncertainty in radiometric dating is more than a decade, so you can't connect records from different parts of the world to a single decade in time. His error was in failing to recognize this uncertainty in time. So the test for "unprecedentedness" has to be done over a longer timescale, like perhaps 50 years, and the total interval might need to be only 1000 or 1500 years rather than 2000 because of limitations in the older data. But in the end this is only one small part of the story, and in the end what matters far more than the size of past temperature changes is the ability to explain them based on fundamental physics.
120250. scaddenp at 12:33 PM on 30 April 2010
        Common graphical tricks and the Medieval Warm Period
        "The issue remains - are our reconstructions valid? If not, no hypotheses can flow from them. If they are, then AGW is a prime suspect and our world faces major decisions with very wide ranging impacts." But hypotheses about AGW DONT come out of paleoclimate. This is the important point. AGW is byproduct of a theory of climate which comes out of physics. In turn, if it is valid, then it should be able to reproduce past climate given past forcing, (obviously within the uncertainties to which you can measure both past global climate and forcings). Its a test of a model, not the progenitor of a model.

Prev  2397  2398  2399  2400  2401  2402  2403  2404  2405  2406  2407  2408  2409  2410  2411  2412  Next