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johnd at 08:02 AM on 22 July 2010Rebutting skeptic arguments in a single line
scaddenp at 07:07 AM, re "15-20 years of flat or negative temperatures while GHGs rise would clearly invalidate AGW." Would the converse also apply, IE. 15-20 years of flat or negative GHG whilst temperatures rise? -
Peter Hogarth at 07:51 AM on 22 July 2010Models are unreliable
Pete Ridley at 22:54 PM on 21 July, 2010 I was intrigued by your note 2) which contains this: "A meta-analysis of all the articles written on the subject showed that the vast majority of experts believe that not only was the MWP widespread but that average temperatures were warmer than they are now" Perhaps this needs a bit of VV&T...? -
actually thoughtful at 07:27 AM on 22 July 2010Models are unreliable
And why do you want climate modelers to debate, other than as yet another delay tactic? Why don't you create a model that account for everything the AGW models do, and prove to the world that man-made CO2 is simply not an issue? The debate of ideas, not names, not titles, not one-liners is the debate that matters to me. So Pete Ridley, where is your competing, complete non-AGW theory of climate change, complete with models that have excellent hind-cast ability, and whose ability we can compare to Hansen 1988, or any of the newer, better models that have come out in the last 22 years? -
scaddenp at 07:07 AM on 22 July 2010Rebutting skeptic arguments in a single line
Pete Ridley - "Some sceptics are arguing that the “slump”... ". And this opinion is based on what physics? 15-20 years of flat or negative temperatures while GHGs rise would clearly invalidate AGW. However, the point that Gavin is making is that models do not produce linear warming and demanding that do is a straw man. The actual pattern of temperature rise that you get in the model depends on how the model is initialised. The nature of the models is that are predicting climate not weather - trends over a 15-20 year. They do not have the skill to predict shorter periods and make no claim as such. Everyone might wish they do but so far this has not been possible. The predictions that do make are rather accurate and in this I mean the patterns of warming, not just the temperature trend. (eg warmer nights, arctic amplification, upper stratospheric cooling, warming ocean etc) "I would suggest that one shouldn’t assume that any of the models are able to make reliable predictions/projections of global climates even for just a decade from now, never mind to 2100." You can suggest butterflies in India are responsible for climate but until to you provide a basis for your suggestion, how would we take it seriously? This is to profoundly misunderstand the nature of the models. Hansen 1988 did very well for a model so primitive. My favourite analogy - put a large pot of water on a flame. You will have a hard time predicting the surface temperature distribution beyond a certain accuracy - however you can make the completely solid prediction that the pot will get warmer. -
Tom Dayton at 06:50 AM on 22 July 2010Models are unreliable
Pete Ridley, evidence of predictive ability was described in the original post at the top of this page. I suggest you read it. -
Ned at 06:15 AM on 22 July 2010Models are unreliable
actually thoughtfull and Pete Ridley, I suggest avoiding carrying over Pete's comments about user names from the previous thread. As far as I know there is no policy here of privileging "realistic-sounding full names" over others. Comments that disparage the choice to use a pseudonym are offtopic and will probably be deleted. -
Marcel Bökstedt at 06:08 AM on 22 July 20103 levels of cherry picking in a single argument
Tony Noerpel> Yes, the pacific oscillation could be part of the explanation. In the 1998 el Nino event there was certainly energy transfered from the sea to the atmosphere, which hasn't happend to the same extent later. But a complete explanation might involve a precise description of the global energy budget, and it seems that people can't do that yet. Jeff> I agree with what you write, but that does not explain why the areas sampled by hadcrut have not warmed much during this decade. I would like to have some mechanism for this on the table. -
actually thoughtful at 04:11 AM on 22 July 2010Rebutting skeptic arguments in a single line
42 CBDunkerson - THANK YOU - now it makes sense. -
Tony Noerpel at 02:29 AM on 22 July 20103 levels of cherry picking in a single argument
Hi Marcel 1998 was a huge step wise increase in temperature from prior years. Note that 1987-1995 looks like a plateau as well. The el nino in 1998 was a 2-sigma event (it was the strongest el nino on record) so very rare and not likely to be matched if the temperature was not rising, yet it was closely matched nearly every year even in figure 1. You might want to think about it this way: that the temperature never recovered from the extremely high level reached in 1998 (its highest level in the record) and now it is going even higher. Yes, ocean and atmospheric circulation move heat around from lower latitudes to higher latitudes but it is not temporary. It is ongoing since solar insolation is strongest at lower elevations. Lower elevations tend to be where the people are. :+) Tony -
muoncounter at 02:22 AM on 22 July 20103 levels of cherry picking in a single argument
#19: 0.47C per decade is the straight line trend over the entire 30+ years of the UAH North Polar LT dataset. Data shown below. But the smoothed curve(purple) shows a higher rate of increase from '92 on, as high as 0.9 degC per decade or a more modest 0.7 deg/dec if you prefer a straight line from Jan92 to Jan2010. Either way, the Arctic region has the highest rate of temperature increase on the planet.
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actually thoughtful at 02:15 AM on 22 July 2010Models are unreliable
Pete Ridley (whoever you are) - it seems your points were addressed on the other thread - yet you repeat them here. Can you state your beef in a a sentence or two, instead of a fully annotated paper? I think the strongest rebuttal to the skepticism of the model-making process is that they can both hindcast (the easy part) and predict - 22 years isn't as good as 5 decades, but how many years of successful modeling will you need before you are satisified?Response: Quick comment - they're repeated here because I emailed Peter and asked him to move the discussion to this more relevant thread. -
Rob Honeycutt at 01:58 AM on 22 July 20103 levels of cherry picking in a single argument
David Horton @ 3... I'll toss myself into the fray with the common punters on this one. But what I think is interesting is that, because of people becoming more interested in this complex issue, they are learning a thing or two along the way. Two years ago most outside of science didn't know the definition of the term "statistical significance." The flap over the Phil Jones interview threw that term into the main stream. People had to learn what "p-value" is, how it is calculated and how it works. Okay, maybe it went right over the heads of a lot of punters but it stuck with others. Climate involves a lot of charts. The charts, I think, are slowly making people just a little smarter. Slowly. That's a good thing. -
DarkSkywise at 01:40 AM on 22 July 2010Rebutting skeptic arguments in a single line
Would it be possible to get something like this for the translators too? (Yes, I'm one of those.) :D As it is now in the translated sections, the titles (like "Did global warming stop in 1998?") wind up as the sceptic arguments in the Arguments list (while they aren't) and the rebuttal is the entire content of the green box in the actual article, which sometimes is kinda, well, long. :P Proposed adjustments: - make the bold first line in the "red box" show as the sceptic argument. (I could use the sceptic arguments as titles so they'd show in the Arguments list, but that'd mean misleading titles like "We're heading into an ice age!" or "It's cosmic rays!", which I assume we don't really want.) - make an extra window for a short rebuttal, which doesn't show up in the actual rebuttal article but only on the Arguments list. If no short rebuttal is submitted, the content of the green box is used automatically instead. *hurries back to working on "Wordt opwarming veroorzaakt door kosmische straling?"*Response: Re translations and the one-liners, I'm going to shortly restructure the whole rebuttal database so that will throw everything into disarray and we'll need to rethink the whole translation system too. We'll cross that bridge when we get to it. -
Jeff Freymueller at 01:34 AM on 22 July 20103 levels of cherry picking in a single argument
#18 Marcel, I don't see how Figures 2 and 3 disprove each other, and I didn't see anything in the post that claims they did. Figure 2 just emphasizes how HadCRUT undersamples some areas of the most rapid warming. That's relevant to the point that 1998 was the hottest calendar year in HadCRUT but not in some other temp series, but I don't think John was trying to claim anything more about Figure 2. -
CBW at 01:24 AM on 22 July 20103 levels of cherry picking in a single argument
David Horton @ 3, I agree that many people have trouble with graphs (and statistics). That's why I think it is important to relate to people's experience and to present the information in a way that is accessible to them (not just to other scientists). Below is one of my favorite plots from GISS because I think people can grasp it intuitively (blue=cool, red=warm):It's hard to look at that and not see a warming trend.
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skywatcher at 01:00 AM on 22 July 20103 levels of cherry picking in a single argument
Some great examples of cherry picking in the posts above, as if to prove John's point. Yes, HadCRU shows limited warming (though still warming) over the past 12 years, but this is not exactly unusual for this dataset:[ergh, not sure the woodfortrees graph is going to show, shortened link with a tinyurl. It showd HadCRU 1977 to present, with relatively flat streches between 1977-1987, 1987-1997 and 1998-present - ie decades of relatively flat temperature, but of course the climatologically significant upward trend is strongly and significantly positive.] You can pick out several relatively flat regions in the Hadley dataset, but the long-term trend is still upwards, just as in all the other datasets. The analyses such as ECMWF and GISS explain the reasons for some of the discrepancies, with the missing of remote regions, while also showing that the warming is not "hidden" - it is present and observed, just not in the Hadley dataset of the past decade. Quite why the regions in the Hadley dataset show a more pronounced 'stepping' pattern over the past few decades is perhaps an interesting question in itself, but it is clear from observations the global temperatures and global heat content show a much steadier upwards trend. There is absolutely no reason to suggest we're anywhere other than on one of Hadley's 'steps' on it's upward progression.
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barry1487 at 01:00 AM on 22 July 20103 levels of cherry picking in a single argument
@HumanityRules"Also deniers criticize GISS for the way it extrapolates(?)"
As skeptics seem to prefer the UAH satellite record above all others (it is compiled by John Christie and Roy Spencer, whose work is published regularly at WUWT), it's worthwhile pointing out that they derive a North Pole temperature trend of +0.47C per decade over the last 30 years. http://vortex.nsstc.uah.edu/public/msu/t2lt/uahncdc.lt (Decadal trends are given at the bottom of the page at the UAH link above) That's right - nearly half a degree Celsius every ten years. At 3 times greater than the global trend, UAH NP data corroborates GISS and ECMWF finding accelerated heating in the Arctic. -
Marcel Bökstedt at 00:54 AM on 22 July 20103 levels of cherry picking in a single argument
Jeff> I don't doubt that the Arctic is warming. And I'm not trying to argue that global warming has stopped. But you have two sets of data (like figure 2 and figure 3), you usually don't claim that one set disproves the other. Preferably you want to have some understanding of both sets simultaneously. So I'm wondering about what has been going on in the last decade, and if there is some understanding of why the different measurements seem to give different trends (in the last decade). -
Jeff Freymueller at 00:38 AM on 22 July 20103 levels of cherry picking in a single argument
#12 Marcel, I should have added in my response that that what the post is really about is the multiple levels of cherry-picking required to even make this particular argument. That's the central point. -
Jeff Freymueller at 00:37 AM on 22 July 20103 levels of cherry picking in a single argument
#12 Marcel, the post is not claiming that the warming is continuing but is in hidden places. Living (almost) in the Arctic myself, I can assure you that very large areas of the Arctic are indeed warming, whether or not there are weather stations there. There is plenty of non-instrumental evidence that the weather station observations are representative. But I don't see how you can make your argument looking at Figure 3. Clearly, even with something as simple as averaging over the solar cycle, there is no substantial (visual) change in trend going back as far as the 1970s. I think the same would be true if you updated the figure to 2010. If you want to do a real statistical test, that's a better way to test whether the trend has changed since year X, but to do that you need to base the trend on more than a decade -- more like 20-30 years. -
Lars Träger at 00:33 AM on 22 July 2010The Missing Link, Creationism and Climate Change
Odd that nobody commented on the quoted anecdote about Ohm. Quote Wikipedia: "When Ohm first published his work [...]; critics reacted to his treatment of the subject with hostility. [...] The prevailing scientific philosophy in Germany at the time, led by Hegel, asserted that experiments need not be performed to develop an understanding of nature because nature is so well ordered, and that scientific truths may be deduced through reasoning alone. " IOW: Not "It's too simple" but "We don't need no stinking empirical evidence, reasoning dictates it's getting warmer because the sun did it." Anybody surprised? -
muoncounter at 00:31 AM on 22 July 20103 levels of cherry picking in a single argument
Here is a 2008 version of ocean heat content. If you fast forward down to fig 9 on p. 13 of the pdf and fig 12 (p. 16), you get a very clear picture (graph) of the results. Very consistent with the ocean heat content that John shows above. Arguing why one interpretation is 0.1C higher or lower than another, or why temperature profile X is flat for 5 years while temperature profile Y is increasing? That's fine when it comes to working out the details, but it obscures the overall story (which is exactly what the denialists want). As CBD says (#8) "it's down to disputing the margin of error", a far cry from HR (#4) "many records exist, all with pros and cons. It seems that this fact allows for multiple interpretations." We can't allow a reasonable discussion over margin of error to be turned into 'there's no consensus' or 'the science isn't settled'. -
Jeff Freymueller at 00:28 AM on 22 July 20103 levels of cherry picking in a single argument
#10 HumanityRules, I suggest you get a calculator and a table of numbers and check it yourself. It is not complicated (add 11 numbers and divide the sum by 11). Every year is equally represented in the moving average. The moving average is doing exactly what it should, and stops exactly where it should given the data in the figure. You are not doing yourself any favors by suggesting otherwise.... As for your comment #1, certainly it is true that WUWT and actual scientists have different interpretations of the recent record, but we will know in a few years how that turns out. My money is not on WUWT in that bet. But I am sure WUWT will simply move on to other claims by that time. Given that the last 12 months have been the hottest 12 month period on record, I predict that WUWT and others will be dropping the "no warming since 1998" claim within a couple of years at most, because even the cherry-picked version will be untenable. But you are correct that an 11-year moving average is not the right tool to evaluate a claim that the temperature trend has changed. For that, you would need to use a 20-30 year average so that you could average out more of the natural variability. The other point about this denier argument not addressed here is that the post-1998 record is too short for a statistically significant trend given known variability in climate. I'm sure John left it out because he chose to focus on the cherry picking x3 aspect of the argument here. But you can see simply by averaging over the solar cycle that there is no radical change in trend at 1998. -
Alexandre at 00:23 AM on 22 July 20103 levels of cherry picking in a single argument
They'll soon have this 'skeptic' argument recycled: "It hasn't warmed since 2010" or "GW stopped in 2018" This global warming never stops stopping! -
Marcel Bökstedt at 00:10 AM on 22 July 20103 levels of cherry picking in a single argument
Way> Yes, it's true that we don't necessarily have that each year is warmer than the previous one. Even if we do have global warming, it could be that the global temperature stagnates or falls over a period of a few years. But the claim of this post is not that this is what has been happening over the last decade. The claim of the post is that global warming has continued, but that it has occured in somewhat hidden places. So my question is 'if global warming has been happening throughout the last decades, why can't we see it as a continuation ot the temperatures increase in the hadCRUT record?' -
robert way at 23:33 PM on 21 July 20103 levels of cherry picking in a single argument
Bokstedt, Global Warming is Visible in the last decade. It is the warmest decade on record for Hadcrut for example. Global warming does not mean each year or 2-3 year period will be warmer but it does mean that one would expect increasingly warmer longer time periods. -
HumanityRules at 23:26 PM on 21 July 20103 levels of cherry picking in a single argument
8 CBDunkerson #1 I guess I'm not looking for perfection just pointing out there is a lot of products to choose from. The fact that people make their point using one or another product is as you say playing with the margins. WUWT will argue to the death that post-1998 is flat, John will do the opposite. I wonder if it would be fair to suggest the rate of increase has slowed? #2 I was surprised that Murphy's paper assumes 40% of the ocean heat is 'hidden' in the deep ocean. It's that sort of assumption that allows them to match the satellite and OHC data. I'm not sure everybody would agree with that assumption. #3 "In Fig1 every value AFTER the 1998 peak is higher than every value BEFORE the 1998 peak". Agreed but nobody is arguing a decline relative to pre-1998 temperatures. I was looking at the HADCRUT data in Fig5. There you can see the dots for each year and it's not the case that every years is hgiher than the previous. Yet the 11-yr average is still going up. That must mean those final years are not yet properly represented by the 11-yr moving average. In fact the 11-yr averaging stops before the point where the year-on-year temperature shows the flattening phase. I take the point that a moving average will smooth things out to reveal the long term situation but we're not talking about the long term situation. John is specifcally countering deniers post-1998 temperature claims. I don't see that an 11-yr moving average is the right tool for disucussing that particular data. -
Pete Ridley at 23:02 PM on 21 July 2010Rebutting skeptic arguments in a single line
Sorry, wrong link - should be http://www.skepticalscience.com/argument.php?p=4&t=189&&a=15 -
Pete Ridley at 22:54 PM on 21 July 2010Models are unreliable
John has asked me to make my comments on this thread rather than on his more recent “Rebutting skeptic arguments in a single line” thread (please see those I made today – Note A) Let me kick off here by posting a comment that software developer James Annan, who is presently involved with the Coupled Model Intercomparison Project (CMIP) (Note B) declined to post on his "Penn State Live - Investigation of climate scientist at Penn State complete" thread (Note C). *************** I have been engaged in an interesting discussion over at William Connolley’s blog (Note 1) about the relevance of established VV&T procedures to climate models and Steve Easterbrook appeared to be suggesting that CMIP was the appropriate solution. I understand that CMIP is a project for comparing climate model outputs and I asked IPCC reviewer Dr. Vincent Gray for his views on this and he rejects the notion that the inter-comparison of the outputs of different models is anything to do with validation. As you may be aware, Dr. Gray is author of “The Greenhouse Delusion”, a member of the New Zealand Climate Science Coalition (Note 1) and was responsible for having the IPCC admit that climate models had never been properly validated, despite the IPCC trying to suggest otherwise. (In response to his comment the word "validation" was replaced by "evaluation" no less than 50 times in the chapter on "Climate Models - Validation" in an early draft of the IPCC's "The Science of Climate Change".) Since you are a member of the Global Change Projection Research Programme at the Research Institute for Global Change working on CMIP3 with an eye on AR5 you may be aware of the extent to which VV&T procedures will be applied. Are you able to point me in the direction of the team responsible for these activities? William seems reluctant to let me participate further on his blog since I commented on his Green Party activism and his reported Wikipedia activities (Note 2 & 3) so I hope that you will take up the debate about the relevance of VV&T for climate models. I get the impression some of you involved in climate modelling see little further than your software engineering and the quality of that software. VV&T as applied in the development of Telecommunications support systems when I was involved in it considerd the full picture from end user requirements definition through to final system integration and operation. (Contrary to what is claimed in “Engineering the Software for Understanding Climate Change” by Steve Easterbrook and Timothy Johns (Note 4) in the case of climate modelling systems, the primary end user is not the scientists who develop these systems.) Although VV+T alone will not produce quality software I recall plenty of instances when professionally applied and independent VV&T procedures identified defects in system performance due to deficient software engineering. Consequently deficiencies were rectified much earlier (and much cheaper) than would have occurred if left to the software engineers and defects only identified during operation. It is possible but highly unlikely that VV&T doubled the cost of the software, as claimed by one software engineer on William’s blog but it would certainly have cost many times more if those defects had remained undetected until during operational use. I don’t expect to be the only person who has had such experiences. I would be surprised if rectification of these software deficiencies led to “quality” software but they did lead to software and operational systems that more closely satisfied the end users’ requirements, used throughout the system development program as the prime objective. Steve Easterbrook and Timothy Johns said (Note 4) “V&V practices rely on the fact that the developers are also the primary users”. It could be argued that the prime users are the policymakers who are guided by the IPCC’s SPMs which depend upon the projections of those climate models. Steve and Timothy “hypothesized that .. the developers will gradually evolve a set of processes that are highly customized to their context, irrespective of the advice of the software engineering literature .. ”. I prefer the hypothesis of Post & Votta who say in their excellent 2005 paper “Computational Science Demands a New Paradigm” (Note 5) that “ .. computational science needs a new paradigm to address the prediction challenge .. They point out that most fields of computational science lack a mature, systematic software validation process that would give confidence in predictions made from computational models”. What they say about VV&T aligns with my own experience, including “ .. Verification, validation, and quality management, we found, are all crucial to the success of a large-scale code-writing project. Although some computational science projects—those illustrated by figures 1–4, for example—stress all three requirements, many other current and planned projects give them insufficient attention. In the absence of any one of those requirements, one doesn’t have the assurance of independent assessment, confirmation, and repeatability of results. Because it’s impossible to judge the validity of such results, they often have little credibility and no impact ..”. Relevant to climate models they say “A computational simulation is only a model of physical reality. Such models may not accurately reflect the phenomena of interest. By verification we mean the determination that the code solves the chosen model correctly. Validation, on the other hand, is the determination that the model itself captures the essential physical phenomena with adequate fidelity. Without adequate verification and validation, computational results are not credible .. ”. I agree with Steve that “further research into such comparisons is needed to investigate these observations” and suggest that in the meantime the VV&T procedures should be applied as understood by Post and Votta and currently practised successfully outside of the climate modelling community. NOTES: 1) see http://nzclimatescience.net/index.php?option=com_content&task=view&id=374&Itemid=1 2) see http://www.spectator.co.uk/columnists/all/6099208/part_3/i-feel-the-need-to-offer-wikipedia-some-ammunition-in-its-quest-to-discredit-me.thtml 3) see http://www.thedailybell.com/683/Wikipedia-as-Elite-Propaganda-Mill.html 4) see http://www.cs.toronto.edu/~sme/papers/2008/Easterbrook-Johns-2008.pdf 5) see http://www.highproductivity.org/vol58no1p35_41.pdf ************** I’m disappointed (but not surprised) by the reluctance of software developers like James, William Connolley and Steve Easterbrook to have open debate with sceptics about the extent to which their climate models have been validated. NOTES: A) see http://www.skepticalscience.com/Rebutting-skeptic-arguments-in-a-single-line.html#comments B) see http://www-pcmdi.llnl.gov/projects/cmip/index.php C see https://www.blogger.com/comment.g?blogID=9959776&postID=2466855496959474407 Best regards, Pete Ridley. -
Marcel Bökstedt at 22:44 PM on 21 July 20103 levels of cherry picking in a single argument
In principle I agree with the analysis that global warming is continuing to happen. Still, I feel that there is something to explain about the hadcrut graph. When you stare at it, you cannot escape the impression that it does look like the temperature has stopped rising. I do understand that the graph represents a rather small area, and that if you extend your coverage to include among other things the Arctic and the sea, that picture changes. But do we understand why the global warming is not visible in the last decade of the hadcrut sample? Is there some known mechanism that at least temporarily steals heat from the populated part of the globe and deposites it elsewhere? -
batsvensson at 22:40 PM on 21 July 2010Hotties vs Frosties?
This entire article could be condensed into the single statement: it is getting warmer not because any observable measurement says it but because a model say it will. That is an argument the "frosties" been using all the time. -
Pete Ridley at 22:28 PM on 21 July 2010Rebutting skeptic arguments in a single line
Just to let you know that John has asked that comments about the computer models be taken to his http://www.skepticalscience.com/climate-models.html thread. -
CBDunkerson at 21:31 PM on 21 July 20103 levels of cherry picking in a single argument
HumanityRules, in answer to your numbered points; #1 - The readings shown in Fig2 are clearly land based, but HADCRUT (like GISS & NCDC) combines those with sea surface temperature readings to get the global anomaly. The land vs sea vs combined results can be seen here. It is accurate to say that none of the temperature trend methodologies are perfect... for that we'd need to somehow measure the temperature of every cubic inch of the atmosphere and oceans every second. However, given that they all have DIFFERENT liabilities yet all show similar results it seems difficult to argue that those results are incorrect. Basically, it's down to disputing the margin of error within a POSSIBLE range of about +/- 0.03 C per decade. #2 The planet's energy budget can be determined either by measuring incoming and outgoing energy (via satellites) OR by measuring energy accumulating within the planetary system (mostly ocean heat content). Willis is an ocean researcher and largely correct that there isn't enough solid data there to make definitive statements. However, the satellite record is longer and more certain. Having agreement between both (as we now do for a short timeframe) increases the certainty of the results, but the satellite values alone also make a strong case. BTW, Murphy's 'exaggerated' results are more consistent with the satellite record and current OHC data. #3 This is just math. Look at the values BEFORE 1998 in Fig1. They were clearly lower. Thus, in the running average graph those values 'drag down' the 1998 result... but the 1999 result has one fewer year of those low values averaged in, the 2000 result has two fewer years, et cetera. In Fig1 every value AFTER the 1998 peak is higher than every value BEFORE the 1998 peak... thus a running average is perforce going to show continued increases. Fig5 was released in 2008 and thus the average line doesn't show results after 2002 (though the circles for 2003-2007 are given). If it did there'd be a flattening out in 2003 & 2004. The 2005 value won't be computable until 2010 is over, but if temperatures continue the way they have been thus far this year the 11 year average would then start rising again. -
Pete Ridley at 21:13 PM on 21 July 2010Rebutting skeptic arguments in a single line
Scaddenp (whoever you are) thanks for those links. I see that the Realclimate article (Note 1) suggests that “we have come out of the recent La Niña-induced slump .. ” Some sceptics are arguing that the “slump” will continue for a few decades at least so it will be interesting to see if in 2040 Gavin is still sticking to his opinion that “.. temperatures are back in the middle of the model estimates .. ” or if he’ll find some way of spinning the continuing cooling into a result of our continuing dependence on fossil fuels for economic growth. I love this statement of Gavin’s “there are multiple model runs that have a lower trend than observed .. Thus ‘a model’ did show a trend consistent with the current ‘pause’. However, that these models showed it, is just coincidence and one shouldn’t assume that these models are better than the others. Had the real world ‘pause’ happened at another time, different models would have had the closest match ..”. I would suggest that one shouldn’t assume that any of the models are able to make reliable predictions/projections of global climates even for just a decade from now, never mind to 2100. As Dr. Vincent Gray said recently “ .. It has to be admitted that climate models have never been validated in the manner I have stated. They always forecast so far ahead that nobody is able to check, and if they are tempted to forecast just a few years ahead they always have an excuse when it fails .. ”. NOTES: 1) see http://www.realclimate.org/index.php/archives/2009/12/updates-to-model-data-comparisons/ Best regards, Pete Ridley. -
adelady at 20:49 PM on 21 July 20103 levels of cherry picking in a single argument
HRules "#3 I am confused why the HADCRUT appears to showing a flattening..." I thought it was commonly accepted that HADCRUT's lack of data from the regions that are known to be warming fastest - NH polar and near regions - reliably show lower warming trends than other series. -
CBDunkerson at 20:49 PM on 21 July 2010Rebutting skeptic arguments in a single line
actually thoughtfull, the reason for the 'The sun is cooling' rebuttal on the various 'Planet XYZ is warming' claims is that the underlying 'skeptic' argument is that these other planets are warming BECAUSE of the Sun. The reasoning goes that warming on multiple planets can only be caused by a common source... which is of course a logical fallacy, but since the supposed common source has also been in decline the claim is obviously specious. In my opinion the best argument against the various 'planet XYZ is warming' claims is that we have nowhere near enough data for any reasonable person to even make such a claim. Here on Earth we have thousands of temperature stations all over the planet with daily readings going back over a century... and 'skeptics' say we can't pin down the temperature trend from that. Yet for these other planets we have VASTLY less temperature data for a far shorter time and the same 'skeptics' are absolutely convinced that ANY uptick in the readings means a warming trend. -
scaddenp at 20:22 PM on 21 July 2010Rebutting skeptic arguments in a single line
Peter Ridley, you can find links to the Hansen paper and discussion of the predictions here and here for Dec 2009. Note that the nature of the prediction is one of "if you do this, then you get this climate". You have to compare the prediction for the scenario which actually matches what we really got. (Doctored version of the prediction showing actual temperature against a worst-case scenario are common). For recent predictions about future climate, then you try IPCC WG1 of course. Great list of the relevant papers and nice summary of the predictions. -
chris1204 at 20:19 PM on 21 July 20103 levels of cherry picking in a single argument
The sparsity of Arctic data requiring considerable extrapolation juxtaposed with comments as to extreme Arctic warming warrant some caution in the light of the DMI temperature record over the last two years. Of course, two years represent weather rather than climate. Sea ice is doing some interesting things this year (again, weather rather than climate) both in the Arctic and Antarctic notwithstanding the real possibility that land ice sheets may be the more important metric. It's going to be an interesting couple of years as current weather morphs into climate. -
Pete Ridley at 20:05 PM on 21 July 2010Rebutting skeptic arguments in a single line
actually thoughtfull (whoever you might be) are you able to provide a link to convincing evidence that Hansen and his team of computer programmers were able to predict in 1988 what the global climates would be in 2010? I have searched unsuccessfully for this. I did come across an interesting blog “The Discovery of Global Warming” run by Spencer Weart (Note 1). This includes a section on Hanson’s activities surrounding his scare-mongering presentation to a Congressional hearing on a very hot summer’s day in 1988 (Note 2) about his expert opinion QUOTE: .. "with 99% confidence" that a long-term warming trend was underway, and he strongly suspected that the greenhouse effect was to blame .. ”. Is it particularly surprising that during the recovery from an ice age there should be high confidence that there will be a continuing warming trend – until nature decides that it is time for the globe to have another ice age, of course. When that happens can’t we be equally confident that there twould be a peak in mean global temperature, a turning point then a cooling trend? Looking at the Hadley Centre’s “Global Average Temperature 1850-2009” graph (Note 3) couldn’t it reasonably be argued that there are signs of this happening? As far as I can see from the most recent paper that I could find from Hansen et al. “Earth’s Energy Imbalance: Confirmation and Implications” (Note 4) Hansen does not attempt to make predictions of global mean temperature, only comparisons with global mean surface (I take this to mean excluding sea surface but may be mistaken) temperature measurements – Fig. 1. Hadley Centre produce a graph of global average land temperature (Note 5) which shows the reducing warming trend continuing beyond 2005. Sceptics argue that the models can only be made to resemble reality by “tweaking” parameters. The following statement towards the end of the Hansen et al. paper hints of this QUOTE: .. A caveat accompanying our analysis concerns the uncertainty in climate forcings. A good fit of observed and modeled temperatures (Fig. 1) also could be attained with smaller forcing and larger climate sensitivity, or with the converse. If climate sensitivity were higher (and forcings smaller), the rate of ocean heat storage and warming ‘‘in the pipeline’’ or ‘‘committed’’ would be greater, e.g., models with a sensitivity of 4.2- to 4.5-C for doubled CO2 yield È1-C ‘‘committed’’ global warming (3, 4). Conversely, smaller sensitivity and larger forcing yield lesser committed warming and ocean heat storage. The agreement between modeled and observed heat storage (Fig. 2) favors an intermediate climate sensitivity, as in our model. .. UNQUOTE. That word “uncertainty” rears its ugly head again. If you can provide a link to a recent paper in which Hansen actually makes predictions/projections of future global temperature then I would very much appreciate it. NOTES: 1) see http://www.aip.org/history/climate/author.htm 2) see http://www.aip.org/history/climate/public2.htm 3) see http://hadobs.metoffice.com/hadcrut3/diagnostics/global/nh+sh/ 4) see http://pubs.giss.nasa.gov/docs/2005/2005_Hansen_etal_1.pdf 5) see http://hadobs.metoffice.com/hadcrut3/diagnostics/comparison.html Best regards, Pete Ridley -
Daved Green at 18:50 PM on 21 July 20103 levels of cherry picking in a single argument
Hi David , as a average punter I dont mind the graphs , I sorta understand trend lines and smoothing but I would like to learn more so if there a not to technical resource out Id be interested . Anomaly graphs ? how do you set zero line ? is like a base line of what normal varience should be ? . there just an example of my ignorance . :-) -
actually thoughtful at 18:04 PM on 21 July 2010Rebutting skeptic arguments in a single line
So Pete Ridley you think Hansen's 1988 model just got lucky in predicting the climate from then until now? I suppose it is possible. Something can be messy and still be accurate enough. That models are not perfect is not a counter to AGW - it is a fact of life. That an imperfect model can come up with the right answer, year after year (Hansen's 1988 work) - is notable. So does reality trump your criticism? Or do we need a 2nd earth to catch all the intricacies and satisfy the false bar you have set? I have computer models that tell me what size pump I need for certain piping applications. I guarantee the model does not understand chaos theory. It MIGHT be aware of laminar flow. But it gives me the right answer, every time. I am not convinced that a model (which I think almost by definition cannot/will not include every bit of variability in the real-world conditions it models) can't provide good answers. Maybe the current climate models don't actually provide good answers, but to say no model, ever, can provide good answers seems way too strong of a claim. -
HumanityRules at 17:00 PM on 21 July 20103 levels of cherry picking in a single argument
#1 ECMWF in Fig2 seems to be global LAND record from the image, so maybe not truely global? Also deniers criticize GISS for the way it extrapolates(?) the polar regions and for having a land biased. So it seems many records exist, all with pros and cons. It seems that this fact allows for multiple interpretations. #2 Josh Willis said on Roger Pielkes snr’s website “However, I personally belive that there is not a long enough common period between the satellite observations and the RELIABLE ocean heat content record to make any strong claims about the energy budget.” That aside it seems that Murphy vastly exaggerates deep ocean energy content compared with others such as Purkey and Johnson. #3 I am confused why the HADCRUT appears to showing a flattening on the year to year basis since 1998 while the 11 year averaging doesn't. It strikes me that in the averaging process the final years become under reprecedented compared with earlier time points. Won't the flattening of the HADCRUT data only show through over the next few years using this sort of averaging? I'm truely confused by this. -
Peter Hogarth at 16:00 PM on 21 July 2010Part Three: Response to Goddard
HumanityRules at 11:19 AM on 21 July, 2010 We could also argue that the natural and regional variations are superimposed on a global background trend that is now emerging as the dominant warming signal. The 100 year trend, even in Greenland, is significantly positive. There are plenty of papers, some limited data, and documentary evidence of warming in Greenland in the 1930s, and that this is evident in the high latitude NH records and reconstructions (see the last graphic I did in the second Arctic Ice article). The main issue is that it appears to be much more localised than the recent warming. This topic I do find interesting, and am collating references on long term records for a post. -
scaddenp at 15:16 PM on 21 July 2010Rebutting skeptic arguments in a single line
RSVP - that requires political action and variety of strategies is possible. Solving a problem is a separate question to acknowledging a problem exists. What is warped is deciding on the truth of proposition based a perception of what is required for a solution, which seems to be the case for those whose primary concern is something like "AGW causes higher taxes", "AGW is making me be a greeny", "AGW is taking away my toys", rather than "I dont like those solutions, so here is what I think is a better one". This is a place to discuss the science. -
David Horton at 15:11 PM on 21 July 20103 levels of cherry picking in a single argument
I have often thought, since the deniaworld sprang into action, that the reason they can be so successful in misleading people is that the average punter can't read graphs. We in science tend o think of graphs as a perfectly normal way of presenting information, and we understand the conventions and implications. The non-scientist rarely if ever sees a graph, and when they do, as in the global temp graphs, what they see is not a trend, but a wiggly line. So when someone says to them "no warming since 98" they look at the wiggly line and say, oh yes, those temps are all about the same. They cannot, it seems, because of unfamiliarity, cast an eye along the graph and recognise that those wiggles, including the last 12 years, form a trend. And of course they have absolutely no idea of regression analysis. It is difficult, as graphically literate scientists, to put ourselves in the mind set of those to who graphs mean nothing. We might therefore be better to keep pointing out that all the evidence, from all kinds of sources, points in the same direction, rather than relying on graphs as a self-evident presentation of data. -
RSVP at 15:03 PM on 21 July 2010Rebutting skeptic arguments in a single line
For all the denier bashing, I am still waiting to see the list of recommendations to prevent global warming, along with some one-liner impact analysis. -
chris1204 at 14:08 PM on 21 July 2010The Missing Link, Creationism and Climate Change
KR @ 115: Bad arguments tend to be easy to take down! I think that's one of the best internal editors for science - if you publish junk, it will be noted and treated as such. It's a great incentive to do decent work. And a very good incentive to cover your tracks :-) -
chris1204 at 14:07 PM on 21 July 2010The Missing Link, Creationism and Climate Change
Michael swet @ 123: I think Miami and Florida will cope better than we fear. CBW @ 116: To what do they attribute the increase/lack of decrease in the size of the islands they studied? Erosion if my memory serves me well. Michael Sweet @ 130: I believe the New Scientist article cites a peer reviewed reference (included in my post). Feel free to look it up and I'm happy to stand corrected if there's been any cherry picking or other misinterpretation. New Scientist may be a popular science magazine but it tends to follow conventional thinking by and large and tries to be genuinely representative and quotes peer reviewed literature. -
Lou Grinzo at 13:18 PM on 21 July 20103 levels of cherry picking in a single argument
scaddenp: Well said. This is one of the things I find most troubling about climate change -- the more you study it, the more connections you make (like your point about all the data pointing in the same direction), and the more urgency you feel about our situation. Unless, of course, you've decided before looking at the data what the answer is, then you can save yourself a lot of time and effort and just leap to the preferred conclusion. -
robert way at 12:06 PM on 21 July 2010Part Three: Response to Goddard
So at WUWT they have another grace topic up and I posted this response and it was snipped. I said nothing bad and the only thing they snipped was this link.Response: Just went and posted a comment, then noticed your comments are up there again. Oh well, can never hurt to reinforce the point.
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