tag:blogger.com,1999:blog-9959776.post6251978177789402045..comments2024-02-15T04:42:41.606+00:00Comments on James' Empty Blog: The inevitable failure of attributionJames Annanhttp://www.blogger.com/profile/04318741813895533700noreply@blogger.comBlogger16125tag:blogger.com,1999:blog-9959776.post-91235134561234868192013-02-22T04:13:04.287+00:002013-02-22T04:13:04.287+00:00Dr. Annan's response:
"It doesn't a...Dr. Annan's response: <br /><br />"It doesn't address the issue of how much we are changing the climate." was exactly what I was fishing for.<br /><br />In addition:<br />"although the analyses are often presented in terms of global mean temperature, they actually use the spatial patterns arising from the different forcings. It's the land/ocean contrast and strong polar amplification that really shows the warming is not natural."<br /><br />The reason I came here is that dishonest exploitations of this work are the meme du jour and are normally organized; the source usually says something different than the claims about the source. <br /><br />Whatever the cause, and however scientists measure it, consequences are piling up, but I am trespassing to say so here. As David Young says: "free speech, get used to it." His other opinions are not my business.Susan Andersonhttps://www.blogger.com/profile/16935228911713362040noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-69023371718892130112013-02-22T02:49:25.134+00:002013-02-22T02:49:25.134+00:00Further to David's comment, this particular po...Further to David's comment, this particular post is focussing on a rather technical point, which certainly should be of some concern to people working in the area. It doesn't address the issue of how much we are changing the climate.James Annanhttps://www.blogger.com/profile/04318741813895533700noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-77890639409360483682013-02-22T02:44:40.289+00:002013-02-22T02:44:40.289+00:00Susan, Science is science. James is stating thin...Susan, Science is science. James is stating things in scientific terms. I think personally there is a lot of crow to eat for the IPCC and lots of others who have stressed the most dire consequences and the highest estimates. All James is saying is that the highest estimates are very very unlikely. That's a very important point. Exactly what sensitivity is will I'm sure remain unsettled for a long while and may never be known with certainty, after all there is something called irreducible uncertainty. We can't even really define it in a way that's measurable. <br /><br />In any case, extremists will always misrepresent science, whether it be those who you call "denialists" who really have little or no power or Green groups who have a great deal more power and money, or former politicians who like to make tons of money and own private jets. Get used to it. It's called free speech.David Younghttps://www.blogger.com/profile/17029429374522399227noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-862992085156894472013-02-21T23:52:04.972+00:002013-02-21T23:52:04.972+00:00I know I'm relatively ignorant about the scien...I know I'm relatively ignorant about the science here, but I'm seeing you quoted all over the intertubes as supporting fake skepticism. Is there some way you can paraphrase this work in a way that makes it clear that you are working towards more clarity instead of providing fuel to the denial industry? In layman's terms, can you state your conclusion in a way that doesn't discredit everything done by climate scientists for the last century?<br /><br />I understand about single points and have always wondered how a system as complex and chaotic as climate could be predicted, but I do understand that there is trouble ahead - that's pretty obvious to the uninformed. I think that regardless of how chaotic the systems are, there is a measurable influence overall in the larger trends.<br /><br />By the way, my father, Philip W. Anderson, agrees with me, so I'm not just flying blind.Susan Andersonhttps://www.blogger.com/profile/16935228911713362040noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-26190925465685748882013-02-20T11:12:13.054+00:002013-02-20T11:12:13.054+00:00Heh, that new Stott et al. paper appears to be an ...Heh, that new Stott et al. paper appears to be an application of what I was talking about in the comment above regarding the use of Gillett's scaling with Jones' attribution.<br /><br />As anticipated it brings up some strange results. The CanESM2 analysis indicates there could be cooling over the next 40 years, even in the RCP8.5 scenario, while the 4K+ sensitivity CSIRO-Mk3.6 model is deemed not nearly sensitive enough. The upper-end of projected observationally-constrained warming from the latter is off the scale, probably about 3.5ºC by 2050.Paul Shttps://www.blogger.com/profile/15275182941476518621noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-66821560463888957952013-02-20T05:00:07.975+00:002013-02-20T05:00:07.975+00:00One popular way to do short-term transients is a d...One popular way to do short-term transients is a direct scaling of projections according to these attribution coefficients. That works for decadal time scale (maybe up to about 100y, it probably loses physical validity in the long term). In fact this is basically what Gillett did, though those results were only quoted for the 70y (TCR) time.<br /><br />Just saw <a href="http://iopscience.iop.org/1748-9326/8/1/014024" rel="nofollow">this</a> today (open access) which reinforces the points I've been making for some time...that is, the future warming is likely to be towards the lower end of the model projections.James Annanhttps://www.blogger.com/profile/04318741813895533700noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-61840972756678604982013-02-20T02:23:04.774+00:002013-02-20T02:23:04.774+00:00Is there a way to put 'local error' bars a...Is there a way to put 'local error' bars around climate sensitivity or show very short transients? <br /><br />Climate sensitivity seems a reassuring, sane, small, longterm number.<br /><br />It always makes me think of an old joke I just saw someone quote:<br /><br /><b> <br /><br />It reminds me of the old Emo Phillips story, when he was stopped by the highway patrol.<br /><br />Cop: “You were doing 80 – the speed limit here is 50 miles per hour”.<br /><br />Emo: “But I wasn’t going to be out that long!”</b>Hank Robertshttps://www.blogger.com/profile/07521410755553979665noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-79567373978897687552013-02-18T11:25:38.051+00:002013-02-18T11:25:38.051+00:00Interesting to compare the CanESM2 and CSIRO-Mk3.6...Interesting to compare the CanESM2 and CSIRO-Mk3.6 results since they have similar diagnosed 2xCO2 sensitivities (also the Jones attribution for CanESM2 looks quite different from Gillett's).<br /><br />Jones et al. suggest that CanESM2 significantly overestimates the GHG response and I assume the <0 scaling for Other means they find non-GHG anthropogenic influence should be of opposite sign (i.e. warming). On the other, completely contradictory, hand they indicate that CSIRO-Mk3.6 underestimates the response of both GHGs and the strongly net cooling effects of Other. If they applied Gillett's TCR scaling method here it would presumably suggest something like 4ºC!<br /><br />I can't help thinking part of the problem here is related to the increasing complexity of models. The latest generation now mostly include complete indirect aerosol effects, improved aerosol chemistry and transport, more complete complement of aerosol species, stratospheric and tropospheric Ozone, biogeochemical "Earth System" feedbacks.<br /><br />I would anticipate all this makes the job of fingerprint detection much messier than in older models, so you get some strange results when trying to pick apart different influences.Paul Shttps://www.blogger.com/profile/15275182941476518621noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-57981094866275549762013-02-18T09:04:02.416+00:002013-02-18T09:04:02.416+00:00David, the Natural component includes volcanoes, w...David, the Natural component includes volcanoes, which have a pretty clear signature in the record.James Annanhttps://www.blogger.com/profile/04318741813895533700noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-56282784910308859922013-02-18T04:21:27.472+00:002013-02-18T04:21:27.472+00:00It sure looks to me like the models are way off on...It sure looks to me like the models are way off on other anthropogenic forcings. I'm surprised at the better correlation for natural forcings. I thought models had little skill at internal variabilityDavid Younghttps://www.blogger.com/profile/17029429374522399227noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-73223021105170492042013-02-18T02:00:45.417+00:002013-02-18T02:00:45.417+00:00David, these are scaling factors on lots of differ...David, these are scaling factors on lots of different models, it is to be expected that they will differ a lot. Some models overestinte the forcred respose, onthers underestimate it. (The top plot from Gillett et al presents minor methodolodical variations but all with a single model, hence they look more similar).<br /><br />It is worth noting in response to Eli and other previous commenters that although the analyses are often presented in terms of global mean temperature, they actually use the spatial patterns arising from the different forcings. It's the land/ocean contrast and strong polar amplification that really shows the warming is not natural.James Annanhttps://www.blogger.com/profile/04318741813895533700noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-71969843606205322822013-02-18T01:40:37.184+00:002013-02-18T01:40:37.184+00:00Why is the scatter in the second plot so large? ...Why is the scatter in the second plot so large? Was there a methodological problem?David Younghttps://www.blogger.com/profile/17029429374522399227noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-58141583926126200532013-02-18T01:16:09.601+00:002013-02-18T01:16:09.601+00:00Eli goes with "precise" data. Before 19...Eli goes with "precise" data. Before 1900 it was anything but, so if you need long and precise and have anything pre 1900 you lose. Wrt ghg forcing, the variation was so small that correlations would not be very useful<br /><br />Also it would be better to have a metric less lumpy than global anything, although of course that is going to mess up when the data is good enough to use even more. So agreed, this is on a hiding to nothingEliRabetthttps://www.blogger.com/profile/07957002964638398767noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-27509168042722034452013-02-17T23:48:25.030+00:002013-02-17T23:48:25.030+00:00The split is into GHG, other anthropogenic (aeroso...The split is into GHG, other anthropogenic (aerosols etc), and natural forcings like volcanic and solar.James Annanhttps://www.blogger.com/profile/04318741813895533700noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-46658328333222099392013-02-17T22:12:33.983+00:002013-02-17T22:12:33.983+00:00Just wondering what the other bars were. Is NAT n...Just wondering what the other bars were. Is NAT natural variability? In any case, looks like models overestimate temp responseDavid Younghttps://www.blogger.com/profile/17029429374522399227noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-60958381877636681712013-02-17T15:16:49.048+00:002013-02-17T15:16:49.048+00:00On the Jones figure it looks like the GISS models ...On the Jones figure it looks like the GISS models broke their analysis. Has Gavin been dividing by zero again?Paul Shttps://www.blogger.com/profile/15275182941476518621noreply@blogger.com