tag:blogger.com,1999:blog-9959776.post9036701914418754850..comments2024-02-15T04:42:41.606+00:00Comments on James' Empty Blog: Another look at climate sensitivityJames Annanhttp://www.blogger.com/profile/04318741813895533700noreply@blogger.comBlogger63125tag:blogger.com,1999:blog-9959776.post-19454744307128381002010-08-02T01:22:07.335+01:002010-08-02T01:22:07.335+01:00For the information of "steven" and anyo...For the information of "steven" and anyone else happening upon this, I did address this in the following post:<br /><br />http://deepclimate.org/2010/06/06/michaels-and-knappenbergers-world-climate-report-no-warming-whatsoever-over-the-past-decade/<br /><br />There I place the Solomon quote in its proper context.<br /><br /><i><br />But it gets better. For there is the niggling matter of the citation for this sentence from Solomon et al, which turns out to be – wait for it – Easterling and Wehner! But, as we have already seen, that paper points out that the trend “since the late nineties” depends very much on the selection of the start year. <br /><br />1998-2008 gives a range of linear trend from 0.11C/decade (NASA-GISS) down to 0.02C/decade (HadCRUT). But if one starts in 1999, NASA-GISS jumps to 0.19C/decade, while HadCRUT is at 0.11C/decade.<br /><br />So it’s even somewhat debatable whether this set of linear trends should be called “nearly flat” since the “late nineties”. But what is not debatable is the dishonesty of Michaels and Knappenberger in citing Solomon et al as further support for the mendacious claim that surface temperatures have been categorically “flat” and that there has been “no warming whatsoever over the past decade”.<br /></i><br /><br />Solomon is not completely wrong, but somewhat sloppy in her exposition. And she has paid the price in being quoted out of context, and even distorted by Michaels and Knappenberger.<br /><br />By the way, Hansen et al rebutted Solomon's "flattening", pointing to continued decdal increase in global temperature, a point I've made many times.<br /><br />Nice try, steven.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-9959776.post-73694568512763744272010-06-03T09:19:01.437+01:002010-06-03T09:19:01.437+01:00James I really liked the deal you pulled with the ...James I really liked the deal you pulled with the Solomon quote. I trust it will cause Nick and others to meditate on their reasons for holding views. None, that I can see saw fit to reiterate their judgements. That's a fascinating view into their minds and issues of hierarchy that they may want to reflect on. The OTHER thing that is fascinating is that you KNEW that they would fall for the trap, and you must have known that none would come back to say "I don't care who said it." THAT is very interesting. <br /><br />I take it that since you don't exactly take a party line on some things they felt comfortable challenging you. it wasnt so much the statement and its not so much the truth of the matter, but rather the preservation of a hierarchy that matters to them. It is ok for YOU to be mistaken, but not for Solomon to be mistaken. Wow. just Wow.<br /><br />they'll dismiss this.stevenhttps://www.blogger.com/profile/06920897530071011399noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-54573614792882339522010-05-31T09:18:00.060+01:002010-05-31T09:18:00.060+01:00FYI, Hank, that paper is from June 2009.FYI, Hank, that paper is from June 2009.Steve Bloomhttps://www.blogger.com/profile/12943109973917998380noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-19519622679986548412010-05-30T20:00:52.319+01:002010-05-30T20:00:52.319+01:00Weel, this paper is an interesting experiment by J...Weel, this paper is an interesting experiment by James. Having committed to such a method, will Chip and the others react honorably when reality turns around and bites them in the butt?Steve Bloomhttps://www.blogger.com/profile/12943109973917998380noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-86412902499811927352010-05-30T19:05:33.869+01:002010-05-30T19:05:33.869+01:00http://news.concordia.ca/main_story/014941.shtml
...http://news.concordia.ca/main_story/014941.shtml<br /><br />Hat tip to <br /><br />"... an interesting article on results of research with results indicating a direct relationship between carbon dioxide emissions and global warming. Paper to be in June 11 edition of Nature... "<br />http://www.realclimate.org/index.php/archives/2010/05/on-attribution/comment-page-8/#comment-176325Hank Robertshttps://www.blogger.com/profile/07521410755553979665noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-63624421362835830502010-05-29T12:06:59.153+01:002010-05-29T12:06:59.153+01:00Eli assumes, and he could be wrong, that every mod...Eli assumes, and he could be wrong, that every model does a spin up when conditions are held constant or runs a check when the conditions are held constant, and they check those results against the observed statistics of variability. Indeed, it was such a simple check that was shown as strong evidence that the GISS 1988 model was reasonable.EliRabetthttps://www.blogger.com/profile/07957002964638398767noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-88592498623744155502010-05-29T12:03:21.176+01:002010-05-29T12:03:21.176+01:00Eli is pleased to see that James is paying a bit f...Eli is pleased to see that James is paying a bit for his Curry worst.EliRabetthttps://www.blogger.com/profile/07957002964638398767noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-17028907997935494272010-05-29T06:06:42.657+01:002010-05-29T06:06:42.657+01:00Very helpful.
Was there any reason to think those...Very helpful.<br /><br />Was there any reason to think those models of that era would have been expected to resolve 'lulls' in warming of 5-15 years? My impression was that it was only a few years ago that models were being talked about that could give that sort of expectation.<br /><br />Can't you also show that those same models -- or some of htem -- couldn't discriminate relatively small geographic areas accurately either? <br /><br />I'm sure I've seen mention of known model failings, like -- I've forgotten, is it that all of them or all but one or two fail to match an alternation between hemispheres that's known to happen in reality, or show an alternation when there's a consistent shift?<br /><br />Just trying to get at, how did you choose which models to assess, and were you asking them to show something they could be expected to show as of when they were run?<br /><br />I'm sure there's a statistical assumption in these questions somewhere.Hank Robertshttps://www.blogger.com/profile/07521410755553979665noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-50515179644469952262010-05-29T02:54:23.271+01:002010-05-29T02:54:23.271+01:00There's an archive of model outputs freely ava...There's an archive of model outputs freely available (and will be in due course for the next IPCC). The model trends were calculated by splicing their A1B scenario runs onto the appropriate 20th century hindcasts. A1B emissions/concentrations are certainly close enough to reality for this - in fact any difference in emissions has very little effect over a decade or two.James Annanhttps://www.blogger.com/profile/04318741813895533700noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-61701673625124172262010-05-29T02:03:45.051+01:002010-05-29T02:03:45.051+01:00Thanks, James, this makes it easier to understand....Thanks, James, this makes it easier to understand. I assume each modeling groups isn't adding each new month's contemporary material -- do you pull from an archive of model runs at the IPCC? Can you pull out say all the models and runs that have data covering any time interval you want? I'm not sure how easy it would be to actually redo your analysis with new information or how you'd get it.<br /><br />If you can set up to automatically pull new data and rerun the analysis (and rewrite the paper?) monthly, that suggests a promising new form of scientific publication.Hank Robertshttps://www.blogger.com/profile/07521410755553979665noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-71905574983313012792010-05-29T00:06:35.750+01:002010-05-29T00:06:35.750+01:00Hank, it's the existing (AR4) model ensemble t...Hank, it's the existing (AR4) model ensemble that we used. This is all that is generally available - people are just now doing the next batch.<br /><br />People do indeed expect that the models should represent the statistics of natural variability reasonably well - it's a fundamental requirement of detection and attribution studies - this is not the same thing as matching the specific trajectory, which requires detailed initialisation. This is what Keenlyside and others are aiming for. Testing the observations against the distribution of internal variability is a very natural hypothesis, it's been done (in a simpler analysis, but based on the same principles) on RC for example...James Annanhttps://www.blogger.com/profile/04318741813895533700noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-75037087526115187862010-05-29T00:05:06.599+01:002010-05-29T00:05:06.599+01:00James,
I made no accusation of cherry-picking. I s...James,<br />I made no accusation of cherry-picking. I said you'd used the current data at time of writing, which is fine. My contention is that you've used a quite inappropriate estimate of variability; the low trend during that period is not as far from expectation as your analysis suggests. The fact that four months later it looks like global warming might not have stopped clearly shows that something was wrong with the analysis.<br /><br />It's just a fancy version of "how can there be global warming when it's so cold today?". Not properly accounting for variability.Nick Stokeshttps://www.blogger.com/profile/06377413236983002873noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-43308702011250958032010-05-28T23:50:24.042+01:002010-05-28T23:50:24.042+01:00Ok, I know A1B is a scenario; I know there are a l...Ok, I know A1B is a scenario; I know there are a lot of different groups modeling. Maybe I'm just waiting for something like this, that won't be available until the paper is actually published?<br /><br />Here's a chapter talking about taking climate model results--is this the same kind of procedure you followed?<br /><br />http://cses.washington.edu/db/pdf/wacciach1scenarios642.pdf<br /><br />"On the PCMDI web site (esg.llnl.gov), all modeling centers provided simulations of 20th century climate using observed solar, volcanic, and greenhouse gas forcing. Twenty modeling centers provided simulations of 21st century climate with the A1B scenario ...."<br /><br />You're talking about collecting that kind of information, from different models assuming A1B?Hank Robertshttps://www.blogger.com/profile/07521410755553979665noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-51431821198973656822010-05-28T23:41:33.480+01:002010-05-28T23:41:33.480+01:00> observed trends of zero or less
> for a p...> observed trends of zero or less <br />> for a period of 11 years or <br />> longer fell outside the 95%<br />> range of model variability<br /><br />James, which "model variability"? <br /><br />Which models have the detail needed to assess stretches of low or down trend? Since how long ago? <br /><br />I thought this whole issue was only recently modelable, perhaps starting from the Keelyside model--new since the last IPCC report? <br /><br />http://www.nytimes.com/2008/05/01/science/earth/01climate.html?_r=1<br /><br />Which "model variability" is assessed? The ones that will go into the next IPCC report? The ones used in the last one?Hank Robertshttps://www.blogger.com/profile/07521410755553979665noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-90617122828269203532010-05-28T22:43:29.598+01:002010-05-28T22:43:29.598+01:00Hank,
“ is it fair to say this paper's proced...Hank,<br /><br />“ is it fair to say this paper's procedure was to<br />-- pick 5-15 years up to 12/09<br />-- assess the variability<br />-- choose a statistical test<br />-- conclude there's no basis to say a trend existed during that time span?”<br /><br />No that is not right. The procedure was:<br /><br />--Collect A1B model output to develop the distribution of model projected trends of 5 to 15 years in length (i.e. assess the variability of the projections)<br />--see where the observed trends of lengths between 5 and 15 years (ending in 12/09) fell within the model distributions<br />--assess the probability of occurrence of the observed trends if they were to occur in a model world<br />--conclude that observed trends were pretty unusual (during some periods more so than others)<br /><br />“I'm wondering basically how this is read along with the stories from a year or two ago saying that stretches of fifteen to twenty years are expected from what we know about the variability of the data over the longer term.”<br /><br />We developed a chart that allows you to assess the probability of any value of the observed trend (surface or MSU lower troposphere) from length 5 to 15 years (see slides 6 and 7 of my Heartland presentation for example). As a preview of those slides, we found that observed trends of zero or less for a period of 11 years or longer fell outside the 95% range of model variability)<br /><br />I hope this helps,<br /><br />-ChipChip Knappenbergerhttp://www.worldclimatereport.comnoreply@blogger.comtag:blogger.com,1999:blog-9959776.post-4565006198576978482010-05-28T22:36:11.081+01:002010-05-28T22:36:11.081+01:00alright, don't use the word "tricks"...alright, don't use the word "tricks" though, or only on "Heritage-approved E&E" papers! ;-)Carl Chttps://www.blogger.com/profile/14717209873111026574noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-45402098203201562332010-05-28T22:30:00.286+01:002010-05-28T22:30:00.286+01:00Nick and DC,
Well I hope you will share your conc...Nick and DC,<br /><br />Well I hope you will share your concerns with the author of the statement....which is not from our manuscript, but rather Susan Solomon writing in Science not so long ago. I don't recall the storm of criticism at that, but perhaps it's not so much what you say, but who says it.<br /><br />Nick, I think your accusation of cherry picking is way off base. The paper simply used data available to date at the time of writing and quite clearly checked numerous trend lengths specifically to address that concern. Of course it can be updated, and the calculations re-done, every time another set of figures are published, but doing it in whole years is hardly unprecedented - in fact many "mainstream" scientists still work with data up to 2000, just for convenience. IMO an important function of the paper is to outline clearly how such comparisons should be made in the future and it is a bit of a stake in the ground (hostage to fortune) whatever your expectations. Science is supposed to be about making predictions.<br /><br />Carl, on the contrary I need every paper I can get my name on :-) Well, actually, I believe the method is worth setting out clearly which as well as being basically sound has one or two neat tricks to extract full value from the models (ie using all n-year intervals).<br /><br />I share Chip's amusement at the sudden importance of the sun...James Annanhttps://www.blogger.com/profile/04318741813895533700noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-14472108264610683762010-05-28T22:17:43.937+01:002010-05-28T22:17:43.937+01:00> the OLS trend was zero or below)
> over so...> the OLS trend was zero or below)<br />> over some period of time during<br />> the past 5-15 years.<br /><br />James, is it fair to say this paper's procedure was to<br />-- pick 5-15 years up to 12/09<br />-- assess the variability<br />-- choose a statistical test<br />-- conclude there's no basis to say a trend existed during that time span?<br /><br />I'm wondering basically how this is read along with the stories from a year or two ago saying that stretches of fifteen to twenty years are expected from what we know about the variability of the data over the longer term. <br /><br />I'm not good at statistics, I'm more asking how to trust what's being said about the real world using this paper as support.Hank Robertshttps://www.blogger.com/profile/07521410755553979665noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-45851446711159861332010-05-28T21:52:29.291+01:002010-05-28T21:52:29.291+01:00"local climate sensitivity" might be a u..."local climate sensitivity" might be a useful term, as used here:<br /><br />http://www.skepticalscience.com/On-temperature-and-CO2-in-the-past.html<br /><br />Rather stunning article, for me as an amateur reader anyhow. It certainly puts the decadal variation in context. Or rather outside of the previous context; the info is mostly from:<br />http://dx.doi.org/10.1007/s10584-010-9821-xHank Robertshttps://www.blogger.com/profile/07521410755553979665noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-36984178001595632832010-05-28T21:13:58.679+01:002010-05-28T21:13:58.679+01:00Look, I can’t imagine that there is anyone out the...Look, I can’t imagine that there is anyone out there who doesn’t admit that at some point that global warming (i.e. the rise in the global average temperature) had stopped (i.e. the OLS trend was zero or below) over some period of time during the past 5-15 years. The goal of our analysis (which I think we accomplished very nicely) was to develop a framework for which any observed trend (below zero or not) could be set against model expectations to ascertain just how commonplace any particular observed trend was (in model world). During my talk, I discussed the observed trends ending in December 2009—some one which were indeed below zero (i.e. global warming had stopped over that period of time).<br /><br />Think of it this way: a car sets out towards some destination. And some point in time, we can detect that it stopped (or slowed considerably). We are trying to figure out whether it just stopped temporarily at a red light 9as we might expect), or whether there may be some indication that something was amiss that may (or may not) impact whether it reaches its final destination. We can speculate on any number of reasons why it may have stopped (red light, refueling, driver had to take a pee, flat tire, overheating, complete mechanical breakdown, etc.), but that was not to purpose of the analysis. The purpose of the analysis was to try to determine whether or not we should even start to wonder whether or not the car had stopped (or slowed) long enough to begin to suggest that there may be a problem over what would normally be expected.<br /><br />In my opinion, we found evidence suggesting that global warming had stopped (or slowed) over a sufficient length of time to begin to wonder why.<br /><br />-Chip<br /><br />PS. Carl C: Sen. Inhofe couldn't make it to the conference, so I didn't get a chance to discuss the idea with him. :^)Chip Knappenbergerhttp://www.worldclimatereport.comnoreply@blogger.comtag:blogger.com,1999:blog-9959776.post-69374546236673995202010-05-28T20:50:52.248+01:002010-05-28T20:50:52.248+01:00http://www.heartland.org/donate/PDFs/USATodayAd.pd...http://www.heartland.org/donate/PDFs/USATodayAd.pdf<br /><br />wow you're in such great company "Chip"! I anxiously await your paper with Sen. Inhofe on how the Gulf of Mexico oil catastrophe is great for the environment, as it no doubt provides a "protective coating" on wildlife etc....Carl Chttps://www.blogger.com/profile/14717209873111026574noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-16197851816079175822010-05-28T19:50:36.043+01:002010-05-28T19:50:36.043+01:00http://www.heartland.org/about/globalwarmingexpert...http://www.heartland.org/about/globalwarmingexperts.html<br /><br />Oh come on, a quick glance of their "global warming experts" above (the usual suspects) and it is pretty obvious they just want to hear that a few- year "trend" means "global warming has stopped." And it looks like you played right into their hands for a free trip to Chicago.<br /><br />At least James is such a colossus he can easily straddle papers with the "climategate" anti-heros & with "Heartland" wanna-be's! ;-)Carl Chttps://www.blogger.com/profile/14717209873111026574noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-77763513446352481372010-05-28T16:43:01.718+01:002010-05-28T16:43:01.718+01:00James,
“and even asked him if he thought I could ...James,<br /><br />“and even asked him if he thought I could get an invite too (I was joking about that, I wouldn't have wasted my time on them)”<br /><br />After attending the conference, I am happy to report, that you’d be surprised at how open some of “them” are to frank, open, civil discussions about various aspects of the science. To be sure, gathered all together in a large crowd, the hardliners carry the moment, but in the smaller breakout sessions, there is a lot of interest in how things work.<br /><br />The organizers seem very interested in bringing in scientists of different viewpoints and in fact, a few attended this year’s conference. What most of the attendees found out, was that these folks aren’t the devil, but instead just hard working scientists interested in moving our knowledge forward. For instance, see these comments by Scott Denning (after the commercial, <a href="http://www.pjtv.com/?cmd=mpg&mpid=144&load=3605" rel="nofollow"> http://www.pjtv.com/?cmd=mpg&mpid=144&load=3605</a>).<br /><br />In that regard, I will encourage them to step up their efforts at getting more scientists to come next year and discuss their work. <br /><br />I would recommend to them that you would be a very valuable addition. <br /><br />While your time may be wasted on some, it would not be wasted on all, and in fact, may be less wasted on this group than on many others (you definitely would not be preaching to the choir!)<br /><br />So, maybe I <em>can</em> get you an invitation… :^)<br /><br />-ChipChip Knappenbergerhttp://www.worldclimatereport.comnoreply@blogger.comtag:blogger.com,1999:blog-9959776.post-72976867042138381832010-05-28T16:09:16.064+01:002010-05-28T16:09:16.064+01:00Jeez Louise, guys, there is no great sinister deed...Jeez Louise, guys, there is no great sinister deed going on.<br /><br />I presented the results of some work we have on-going to a conference…this is hardly unusual, if fact, it is the norm. I also mentioned that we are trying to get it published—hardly a shocker. Since we don’t have it published, I didn’t give an explicit reference or hand out any preprints. Instead, I listed me as the presentation giver as well as a list of people who are working on the project. Again, hardly unusual.<br /><br />I guess I don’t see what the big issue is.<br /><br />I started my talk saying that a lot of times you hear “global warming has stopped” but that without any context, it is impossible to determine the significance of such a statement. I then proceeded to describe how we went about trying as best we could (with a bunch of caveats) to actually come up with a way of putting such a statement into context. The way we did it was an extension of the way others have done it (e.g. Easterling and Wehner, GRL, 2009; Knight et al., BAMS 2009). Our findings, summarized in my slide 10, indicate that over the last 5 to 15 years (ending in December 2009) the observed temperatures are very much on the low side of the distribution of model projected trends of similar lengths. So much so, that they are flirting with being statistically different—which indicates that there might be a problem.<br /><br />My slide 12 listed some potential sources of the problem.<br /><br />As far as the statement on my slide 11 “Global warming has stopped (or at least greatly slowed) and this is fast becoming a problem” this seems perfectly in line with our analysis. <br /><br />By “fast becoming a problem,” I mean that as the period of low warming rate grows longer, it pushes more and more towards the left-hand tail of the distribution and into problematic territory, i.e. territory that requires an explanation besides just random occurrence.<br /><br />And as far as solar goes, I must admit to being pretty surprised by the number of people who are coming forward to claim that solar has such a large impact on the temperature trend. When global temperature was trending happily upward, solar was largely dismissed as playing much of a role, but now that the temperature rise has slowed, it’s all about the sun. I find it amusing that many of the arguments made by “skeptics” to try to play down the warming (solar, ENSO, starting and stop dates, etc.) are now being used by folks of the other viewpoint to play down the *dearth* of warming.<br /><br />-Chip<br /><br />PS. Deep Climate; Anthony Watts was the speaker just before me, so it hardly seems out of line to extemporaneously point out to the audience how the results that he just presented impacted my results. At the very least, it seems like common courtesy.Chip Knappenbergerhttp://www.worldclimatereport.comnoreply@blogger.comtag:blogger.com,1999:blog-9959776.post-5320494137090181792010-05-28T15:10:28.832+01:002010-05-28T15:10:28.832+01:00Yes, I would object to the statement cited. The sl...Yes, I would object to the statement cited. The slope of the short trem trend depends very much on the surface data set cited, as well as the specific start and end chosen. As I mentioned previously, there appears to be no analysis of these fluctuations, or indeed any of the uncertainties associated with the short-term observational record.<br /><br />Meanwhile, *over the length of the analysis period*, the long term trend has continued to grow, if anything. And its p-value continues to shrink, indicating ever greater statistical significance. The bottom line is that one can argue that the short-term surface record is consistent with the model projections or with natural variation; it's simply too noisy to distinguish between these. But the long-term trend continues to be consistent only with anthhropogenic forcing.<br /><br />And speaking of the surface record, here is a quote from Knappenberger discussing one of the possible "sources" of the "problem" of model inconsistency with "stopped" global warming, namely "unknown errors in the observational temperature record".<br /><br /><i>As Anthony [Watts] has just shown us, the temperature record is probably warming too much, which would push things even further out on the left, which would cause even more problems with the model projections.</i>Anonymousnoreply@blogger.com