sunny starry skies

But Fairy Nuff's real! And betrothed to Rid Skwerr too. At least in Calton Creek she's real... http://www.netsavvy.co.uk/lobey/cast.htm {scroll down to find Fairy Nuff} Most'll think I'm raving here... These guys are characters from the Lobey Dosser cartoon series by Glaswegian cartoonist Bud Neill in the 40s/50s (http://en.wikipedia.org/wiki/Bud_Neill), about a group of weegies who get transplanted into the Wild West, with all sorts of Glasgow in-jokes, good stories and fun characters. Lobey is the sherriff with his faithful two-legged horse El Fideldo, the chief baddie is Rank Bajin, they live in Calton Creek, and the local Indian tribe chiefs are Chief Toffy Teeth and Chief Rubber Lugs. Good fun! If you click on the names in the links from the page above you'll get excerpt strips from the cartoons.

Hmmm, "leading researchers"? Curry, von Storch, Pielke Jr? Just a wee bit too much 'false balance' going on there from the media (Fred Pearce) here, as they're all from within that 2-3% of climate researchers who don't believe humans are responsible. I'd like to see a story where there are 48 different quotes from within the 97% of actively-publishing scientists on climate who believe that humans are causing a serious problem, with a single quote from a Pielke Jr for balance. That would be balanced reporting! I also hear that Fred Pearce, author of a series of misinforming articles on 'climategate' (http://www.realclimate.org/index.php/archives/2010/02/the-guardian-disappoints/ among others), has a new book to sell on the subject. Despite the repeated clearing of the CRU scientists by inquiry after inquiry (Muir Russell reporting shortly, any bets on whether he'll find serious problems?), Pearce clearly wishes to keep a dead story floating in the hope of selling a few more copies... That said, I agree in principle with your comment Jethro! I think this episode will have changed climate science for the better - it has exposed areas where scientists need to be even more rigorous and clear with data/archiving/access policies. Climate science can only benefit from that I think. sss

Hi G-W, just responding to your comment on my last post, no worries about your 'squiffiness' when writing it! I understand that it is all about the state of this year's pack that will make the progression towards the next minimum particular to this year, and not predictable purely based on previous years, and that's not even including the vagiaries(sp?) of weather! My aim with that little piece of data analysis was twofold - one to correct the erroneous information I posted earlier, and second to provide boundary conditions to what we might expect come this September given the same amount of extent loss to melt as those years (those boundaries came out at between ~3,800,000km2 and 4,500,000km2). Something I didn't mention, perhaps because I specifically didn't want to come across as 'alarmist' was that the volume measures this year are way down on previous years, and you've seen my videos of the Nares strait and you correctly identify the unusually high mobility of the pack this year as another factor. Thos observations would make me predict the ice extent to be in the lower range of the estimates based on previous years come September. And low volume values don't preclude a dramatic retreat leading to a record low value by a large margin through in situ melt-out, as well as transport out of the Arctic basin. The Antarctic is a totally different system, and so there are other processes involved there, some of which G-W points to, and some I mentioned (I think) in an earlier post. It's interesting that the global sea ice albedo is presently approximately constant due to the sea ice increase in the Antarctic, but we need to treat them as two completely separate systems - the Antarctic has little effect on our weather, and does not have the same stores of methane contained within nearby permafrosts. Each area has a susceptible ice sheet nearby (WAIS, Greenland), which are independently capable of adding large quantities of water to sea level. We lose the Arctic cap, and sea ice increases in the Antarctic are not going to compensate! sss

So long as it's a Lagavulin, cheers Y.S.! Though I do not agree with you on many points above, I'm going to let them alone entirely so we can try and discuss 'new research' on the topic in future! I think this debate highlights a problem in blog debates of science, where we each don't trust the basic veracity/honesty of the others' information sources. And if we don't do that, it's impossible to have a scientific debate. 'Lay scientists' (which we all are here to a greater or lesser degree) are just not in the position to judge research quality, because however much we think we understand a topic/an article, we're usually missing some key element that may throw us onto the wrong track. The classic example of this is the "CO2 lags temperature" fallacy, which certain lay people will take as meaning the exact opposite to what the science understands (namely that CO2 is both a capable and a powerful climate driver, rather than the lay interpretation of "CO2 doesn't affect temperature". A fuller understanding of the mechanisms involved easily disproves the fallacy created by the first impression. This sort of thing goes on in myriad more subtle ways as you head deeper into a complex specialism. On the topic of 'new reserch' and a little relevant to what's gone before, I'd like to see bona fide skeptics produce original research data. Instead of attempting to refute and argument by suggesting that "X is wrong, because I theoretically show their methodology is wrong ", why not refute the argument in a scientifically more powerful way by saying "you're wrong, and I can prove it because this dataset, gathered in a way that eliminates your errors A, B and C, shows a clearly different result." To me, this is how the best science is done, and it would be a way for people like MacIntyre (who must have a decent grounding in tree-ring methodology now http://nwstatic.co.uk/forum/public/style_emoticons/<#EMO_DIR#>/laugh.gif), to move the science forwards rather than holding it back. And I think it would gain him a great deal more respect from established scientists in the process than the method of vexatious FOI requests. While their 'data' consists of retrospective data analyses, skeptics (whether ultimately right or wrong) will always be in a far weaker position to comment than those who collect original data, analyse it and publish it in good journals. There's no reason why skeptics can't do the same if their data, methods, results and conclusions are as robust as they suggest. If I get time I'll have a dig in recent research to see if there's something new and interesting for us to discuss. Enjoy what's left of the weekend everyone! sss

Err, yes, as our entire society is based on a climate and sea level close to what we have today. Imagine 100+m sea level rise and mean temperatures 6C higher, forested poles, totally different weather regimes etc. In geological times the planet has been this much warmer, but not recently. Humans will have an awful lot of adaptation to do. The planet will adapt, but can we? sss

interesting question P.P.! At present there seems little I could do to reduce my carbon footprint in my basic lifestyle, bar one thing. I live in a modern flat with relatively few exterior walls and don't need the heating 6 months of the year. Our recycling is such that our wheelie bin goes out every 2-3 weeks only half-full. If we left it longer it would stink:bad: . But that's because our lifestyle doesn't generate much rubbish rather than being holier-than-thou! We do recycle what we can (glass, paper, plastics), though I share G-W's, and other's reservations about where the plastics etc are recycled and what the carbon footprint of that is. Condensing boiler fitted, small car occasionally used - I cycle or bus to work, but I do fly on work commitments once or twice a year, and occasional holidays, and so I suspect my carbon footprint is not the lowest here! I can't fit solar panels (hell up here I'm not sure it's worth it ), We could improve the 'local produce', though for the most part we do what we can. So as far as I can tell the main thing I could do would be fewer flights. sss

Ignoring that it's in weather chart F.I., 4wd, why is it remarkable that the summit of Greenland, in the middle of an ice sheet, 3,200metres above sea level, might be below freezing, whatever the time of year? July is generally the warmest month of the year in the Arctic, as elsewhere in northern latitudes, including the UK. 'Autumn' for polar sea ice surely really begins in September, at the minimum extent of the sea ice 2 1/2 months away. Anyways, I have a confession to make, which says something of showing 'skepticism' in the face of unverified information. I quoted a 'Curious Yellow' on sea ice numbers, and I've seen some big errors on verifying the data! Maybe the mantra is never trust information at WUWT, whether posted by a skeptic or otherwise! There are, of course 78, not 47 melt days between July 1st and September 16th, from the IJIS data, and so Curious Yellow's number were well out. Using the 2003-2009 data, the actual values are: July 2003-2009 daily melt mean: 81,470km2 August 2003-2009 daily melt mean: 51,209km2 Sept 1-16th 2003-2009 daily melt mean: 11,861km2 Applying these mean melts, with associated maximum monthly mean and minimum monthly mean melts to the starting value on June 30th 2010 for the respective 31,31 and 16 days gives me the following projected values as absolute minimum, mean and absolute maximum values in km2 for July 31st, August 31st and Sept 16th. The melt values are coherent melts from individual years subtracted from 2010's June 30th value. June 30th 2010: 8,806,563 July 31st 2010: min=5,842,000 mean=6,281,000 max=6,662,000 Aug 31st 2010: min=4,119,000 mean=4,694,000 max=5,561,000 Sept 16th 2010: min=3,786,000 mean=4,504,000 max=5,396,000 In context, these numbers put the estimated September sea ice minimum at best to be a little above 2009 if melt rates are as small as they have been between 2003-2009 (the 2006 melt season). An average melt rate gives us a 2010 value midway between the record-breaking 2007 season and the 2008 season, the second lowest of all time. A 2007 (or for that matter, 2008) melt rate would give us a new record low extent in 2010, beating the 2007 extent by 468,000km2 (2007 rate, shown above) or by 374,000km2 (2008 rate). Obviously these numbers are merely extrapolations based on the past seven seasons of melt, and the rate could of course be lower than 2006. We'd better hope we don't set any new records for high melt rates. sss

I didn't miss any evidence, Y.S., but lets agree to disagree for the sake of this thread. I'm very happy for readers to make what they will of all the posts and links of all protagonists in our little debate here, as I'm confident the evidence (in the part of wrongdoing) is on Mann's side, based on the numerous expert panels that have shown this. Readers can see for themselves the quality of evidence that is on both sides. I'd highlight that the evidence on the relative scale of Medieval warmth and modern warmth, however, is not a closed question in the eyes of acadaemia, as I've said in a few posts. Indeed, the 'spaghetti graph' of the NAS report shows quite a range of plausible Medieval warmths, of which Mann's would be among the lowest (coldest). While I believe that Medieval warmth was not as great globally as modern warmth, it's fair to say that it's quite plausible (if, perhaps, unlikely) that this is incorrect. Y.S. and I may be rather closer in our views here than he/she thinks! Where I suspect we differ here is the significance of substantial global Medieval warming, if it exists. I think it's an even worse thing for world prognostications because it implies a higher climate sensitivity and all that entails for our modern climate forcing, but I suspect Y.S. does not think so. Jethro makes the excellent point of the real tininess of the 'hockey stick' in the overall pantheon of evidence on anthropogenic global warming - many other points of evidence are far more important, namely those that point to CO2's role, and the direct and indirect anthropogenic signatures of the enhanced greenhouse effect. Mann himself has said he regretted the prominence of the hockey stick in the TAR, because it's not that big a piece of AGW evidence. Lets all have a Saturday night beer, and try and move onto new topics in future! sss

What a surprise... Mann cleared yet again just today, by another report from Pen State University: http://live.psu.edu/fullimg/userpics/10026/Final_Investigation_Report.pdf http://www.realclimate.org/index.php/archives/2010/07/penn-state-reports/ and further background elucidated eloquently by Joe Romm here: http://climateprogress.org/2010/07/01/michael-mann-hockey-stick-exonerated-penn-state/ Hmmm, any more evidence, Y.S of Mann's impropriety, maybe more substantial than the Wegman Report which is known to be a biased and plagiarised report? further information on Wegman here: http://www.desmogblog.com/wegmans-report-highly-politicized-and-fatally-flawed here: http://deepclimate.org/2009/12/22/wegman-and-rapp-on-tree-rings-a-divergence-problem-part-1/ and here: http://deepclimate.org/2010/02/08/steve-mcintyre-and-ross-mckitrick-part-2-barton-wegman/ Specifically they show that the Wegman report had a biased panel from the outset, refused the offer of specialist help of the National Academy of Sciences (I think it's quite remarkable for a government to refuse the help of it's own professional science body on a matter of scientific evidence), then compiled a report full of plagiarism and misrepresentation. You see, the problem here is that allegations become spurious when they are repeated without evidence, or after what little evidence has been repeatedly debunked. We have on one side, a single Congressional report produced for the Bush Administration that is full of all sorts of flaws, little academic expertise and plenty bias. On the other side, we have a whole series of reports: a detailed scientific report by the National Academy of Sciences, two reports by Penn State University, in addition to the findings of the various Parliamentary CRU-type enquiries over here all clearing the scientists of any wrongdoing, and in many cases specifically supporting the science. So keep shouting, Y.S. - it seems all that you, MacIntyre or others have left. Let us know when you are able to convince the experts in multiple fields of relevant science. From the NAS report, immediately preceding one of your cherry-picked quotes above: "The basic conclusion of Mann et al. (1998, 1999) was that the late 20th century warmth in the Northern Hemisphere was unprecedented during at least the last 1,000 years. This conclusion has subsequently been supported by an array of evidence that includes both additional large-scale surface temperature reconstructions and pronounced changes in a variety of local proxy indicators, such as melting on ice caps and the retreat of glaciers around the world, which in many cases appear to be unprecedented during at least the last 2,000 years. Not all individual proxy records indicate that the recent warmth is unprecedented, although a larger fraction of geographically diverse sites experienced exceptional warmth during the late 20th century than during any other extended period from A.D. 900 onward." The NAS is not saying Mann's work was the last word - indeed they acknowledge in detail the observations in various other regions (notably China) of Medieval warmth, but they question the spatial/temporal uniformity of such variations - hence why Mann's graph is perfectly "plausible". That's hardly a scientific crime is it! sss

In Arctic sea ice, no they haven't, and that's the point! Some interesting (as always) analysis from Tamino of data going back to 1970s, and a linked paper with data there back to the 1950s: http://tamino.wordpr...-ice/#more-2908 Seeing as people spent 400 years searching for the Northwest Passage and prior to the mid-20th Century traversing it required a winter-stopover in the ice, yet in 2007 and 2008 it was essentially ice-free (navigable with no icebreaker), and 2007 saw the very first single-seaon traverse without an engine (wiki source), it''s utterly implausible that these conditions have existing during the phase of human exploration of the Arctic. A really interesting bit of data analysis from (shock horror) WUWT.... ah, but it's from a commenter, not a poster, called Curious Yellow (comment at: July 1st, 2010 at 5:54am), which I randomly stumbled upon from a bust link - I certainly didn't read all the comments! It's from Goddard's 11th attempt at Arctic sea ice news, which are, as ever entertainingly incorrect. Curious Yellow's comment: "Lets have a simple pragmatic look at the situation; For the period 2003 to 2009 the acerage daily melt from 1 July to the minimum of each year is 98,142 KM2 per day. The average end of melt date over the same period is 16 September (lowest 9 and highest 24) From 1 July to 16 September there are 47 melt days. If I use the average melt 2003-2009 of 98,142 times 47 days, then another 4.61 million KM2 will melt. Depending on the actual number for 30 June, I assume a starting point for 1 July 2010 to be near 8.80 million KM2. Deduct the average melt of 4.61 million KM2 and the result will be 4.19 million KM2, beating the 2007 record. Hence, in order not to beat the 2007 record there would have to be unusual changes, such as; (1) an unusually early end to the melt period, (2) a daily melt well below average due to weather, or both. Keep in mind that only two melts were below average, 2006 at 75,000 KM2/day and 2003 at 80,400 KM2/day versus a 137,000 KM2/day melt in 2008 and another 3 years 2004/2005/2009 melted just over 100,000 KM2/day." [end of quote] Let's all hope for a below-average melt from now on, and that's just to stop us matching 2007... sss

Good question! I only used this winter to try and get the idea of a spatially heterogeneous pattern across, and the concept that Britain and China might show one thing, but the globe may not. Over one year the pattern wouldn't show, but over 30 or 50 years it might. Indeed discerning a signal is tricky, hence why the TAR 'hockey stick' had significant error bars! But I was imagining those timeseries that are reasonably continuous - they often have highs and lows, even within the same century. I think that's why Mann's global graphs have mostly come out flat - because those highs and lows didn't always match. But other aggregations have a bit more synchrony and show something of a MWP (e.g., NH-only timeseries). It's clearly not an issue where the 'science is settled', to use an ugly phrase, but so far nobody has done better than the recent hockey sticks of Mann or the other 'spaghetti plots' that show more variation, but still the 20th Century uptick. And none of this particular debate changes the cause of the 20th Century rise of course! sss EDIT: I think I've read several on monsoons, but a few years ago now and I don't remember the contents - if you find anything interesting, it might be good for a post!

wow! seems like weeing into the wind... But if it will change the microclimate enough to save their water supply..?? And many will be intrigued to see if they can manage that!

Very interesting Jethro. A question - they may agree that it's the biggest uncertainty, but is it because they think the cloud uncertainty is very large (specifically is it large enough to potentially substantially offset GHG forcing, assuming it turns out negative), or is it because they think the uncertainties in other factors are all much smaller? Clouds are well-known to be uncertain - we don't even know if they'll act as a positive or negative feedback I thought! But do they indicate some idea of the range within which cloud forcing is likely to be confined? Sorry, I can't read the full article as I'm at home to check this out myself. The same PNAS abstract also highlights some more worrying stats on the experts' thoughts on large future temp changes, possible permanent planetary state changes among others, but that's not for the atmosphere page. sss

Sadly 4wd it is down to climate - rather odd, isn't it that higher Arctic temperatures have corresponded to a thinning then loss of Arctic ice. There was a paper recently that attributed some of the 2007 loss to weather, but certainly not all (despite the misrepresentation of the usual websites). If it were purely down to weather then such great thinnings and losses would have been observed before - they haven't. You're right though that weather plays its part from year to year, and that 2007 would not have been quite as bad given differnt weather. But the pack this year has less volume and is weaker than in 2007, and so we'd better hope conditions are not conducive to collapse. I'm encouraged that the rapid melting rate in June has slowed over the last two days, although June still melted ice 17% faster than in 2007. We need to hope that we have a slower-than-average melt in July, just to keep the graph from tracing the 2007 curve. EDIT: critical level 4wd - maybe when the ice gets so thin it can simply melt out? Do you think the ice on a pond ever reaches a critical level, so far as area of pond covered is concerned? Start with 6" ice evenly spread, and melt approximately 1" per day. Which day loses most area? Is it a'critical level? In the Arctic this is a large shiny white thing that will turn dark blue and absorb more heat for increasing parts of the summer when we hit that 'critical level'. I've made two videos of the Nares strait from MODIS data, inspired by Neven's Arctic page (http://neven1.typepad.com/). One is June 2009, the other is June 2010: nares2009_june.wmv Nares Strait, June 2009 nares2010_june.wmv Nares Strait, June 2010 2009's cloudier than 2010, but you can see the intact ice bridge, with little happening down the Nares Strait (top left). Much of the ice is pretty solid, but there's a general flow towards the Fram Strait on the right-hand side as you'd expect. 2010 shows a completely different picture. The ice is visibly more fragmented and weaker, and looks distinctly susceptible to changing winds. Ice is pouring freely out of the Nares Strait like sand through an hourglass, draining this part of the Arctic of its supposedly thicker older floes. The fragmented ice makes its way (out of shot) to the warmer water of Baffin Bay, where it's doomed to melt. I think these videos show the altered nature of the pack from last year to this year, and how it is much more susceptible to melting and out-of-basin losses than last year. sss

Hi Jethro, your last link's European? But yes, you're right in that there are other sites that show a climate anomaly of some sort, some time between 800 and 1300AD - hence the debate about whether the MWP was global or not! The key challenge is whether the ones that show warm temperature anomalies (not precipitation etc) are all occurring at the same time, and showing a uniform warm episode. This is not so clear - for example the Ma et al 2003 paper, as a random example, has three or four data points showing a warm MWP, according to what I can read of the abstract. That's fair enough, but what's happening between the data points? For example a similar stalagmite sampled at 100 year intervals, where the intervals approcimately corresponded to the 1660s, 1760s, 1860s, and 1960s might suggest that temperatures wer relatively cold in the UK? For the most part they would be right, but there's scope to miss data between the points. And if the warm and cold episodes in different locations don't match, the aggregated signal is not necessarily one of significant warmth. The Ma et al paper is entirely justified in suggesting Medieval warmth in China, but is it really the same warmth at the same time as elsewhere? My own feeling, [which I stress is separate from defending the work of someone like Mann from the spurious allegations of someone like MacIntyre] is that it would be surprising if the MWP was not at least hemispheric in extent, due to weather teleconnections. But in a parallel to my conjecture I put out earlier, I find it rather interesting that of all places China is reporting anomalous Medieval warmth. Were they not also anomalously afflicted by the cold winter (while the rest of the world was doing it's best to break high temperatures)? It should highlight in the minds of everyone that individual locations identifying a warm episode are not enough - most locations with a records capable of identifying the warm episode need to record it, or the warmth can be an artefact of patchy heat redistribution rather than a uniform climatic signal. And if the spaghetti diagrams of modern palaeoclimate evolve with new data towards one showing more pronounced Medieval warmth... then woe betide us in the implications for planetary climate sensitivity. TWS - fair point, but the key thing is that basically the whole globe is warming, not cooling, albeit at rather differing rates. That is as expected from the well-mixed CO2 (which is generall a little higher in the NH). Any thoughts on Eocene climate and Arctic sensitivity from the paper I linked to? Should we be worried about a 19C Arctic temperature rise? It sounds mad but anomalies over the Arctic are already pretty large. sss

er, Y.S., I hate to inform you, but Wahl and Ammann was published by Climatic Change in volume 85 (1-2), pp33-69... Wegman has been discredited as I already alluded to in the earlier post. Here are some critiques of that so-called impartial report. http://www.desmogblog.com/sites/beta.desmogblog.com/files/plagiarism%20conspiracies%20felonies%20v1%200%201.pdf - report by John Mashey http://desmogblog.com/wegmans-report-highly-politicized-and-fatally-flawed http://deepclimate.files.wordpress.com/2009/12/wegman-bradley-tree-rings.pdf So far you've provided sources from a book and a very biased blog, plus a load of allegations regarding the honour of several scientists and their methods. Nothing that stands up to scientific scrutiny. So as far as that is concerned, I'm no longer bothered with replying in detail to unsubstantiated material. You never did explain how bristlecone pines affect speleothems... or quite how boreholes, glaciers and speleothems don't qualify as 'non'-tree-ring proxies. Just a load of unsubstantiated suggestions, for which you provide either no reference at all, or Macintyre's blog... You fail to spot that I dealt with your pointing out other random sites showing warmth in some detail in my last post, and acknowledged that if the proxies improve and subsequently show globally uniform MWP/LIA, I'll revise my view. So far they haven't shown that at all, and you have utterly failed to show that. If the MWP was global, and warmer than today... I'll be even more worried about AGW effects. Papers like this one, show exactly why: http://geology.gsapubs.org/content/38/7/603.abstract Arctic temperatures in the Palaeocene ~19C warmer than present with 390ppm CO2. Care to think about the consequences of this for methane release and sea level? sss

Y.S., have you got any better data than one book (not peer-reviewed), and one blog site (Jethro, were we not only supposed to be posting data of academic value?) Bristlecone pines are old hat, the science has moved on, and you're wrong about Mann et al 2008 - they specifically do the reconstruction without tree rings, as well as with. It does not change the conclusions. "Recent warmth appears anomalous for at least the past 1,300 years whether or not tree-ring data are used." [Mann et al, 2008] MacIntyre's methods were discredited by Wahl and Ammann, amongst many others, and his submission to the CRU enquiry was found to be without merit by the enquiry. Why are you so doggedly keen to support MacIntyre when he's provided nothing of significant academic merit? He's also made to look a complete fool by other bloggers (fight bad blog science with good blog science? you don't need a science paper to show he's deliberately wrong - see Deep Climate's recent post and his two "how to be a climate science auditor" or "let the backpedalling begin" posts). The trouble is, Macintyre is so desperately wrong about tree ring data, their use, the concepts involved and the analysis techniques required that he can't bring himself to admit it, or to admit that the tree ring data isn't even required to prove the original point! Pete, you're absolutely right about all proxy data to be treated with caution, and it remains entirely possible that a series of records will somehow show the MWP to be both global and as warm as at present, but so far multiple different methodologies and proxy types are not showing this to be the case. If it's subsequently shown to be global and significant through data that has academic merit, I'll change my opinion on its global significance. I'll also be even more worried about AGW than I was before... Why is it not likely to be global despite individual sites sometimes showing a MWP? How about this: you can argue that proxy A (20deg S), proxy B (50 deg S) and proxy C (40deg S) all show a warm period somewhere in the Medieval. When was it? Was it a uniform, significant event? If 'A' peaked around 8-900AD, 'B' around 1000 to 1100AD, and 'C' around 1200-1300AD what happens? The average signal from the three sites, particularly if one or more show relative coolness at other times, may be a rather muted, or even absent "MWP." As the time loosely described as Medieval covers >500 years, each individual paper could describe finding a MWP at their location, but the MWP is still not global. What happens in the real world is that many NH, and especially the N Atlantic reasonably clearly show a MWP (though there are temporal discrepancies even across the Atlantic), and on the whole the regional warm periods match with each other, indicating widespread regional warmth. Elsewhere, the periods are either absent or do not line up, and when you add all those signals together with the European/Atlantic ones, the global MWP is less impressive than you first thought from a Eurocentric view. As a conjecture, I think this is what you'd expect from a solar-driven climate anomaly - very modest in overall magnitude, but regionally strong, absent or even reversed depending on the patchwork of heat redistribution driven by weather systems. The recent research linking cold European winters to solar minima supports that (think last year!), showing a change in the redistribution of heat around the globe driven by the Sun (though little reduction in radiative forcing), while the globe overall was at near-record high temperatures. So I suggest that solar forcing's most important effect is to alter the patterns of weather, leading to patchworks of warm/cool/little change. Greenhouse warming occurs relatively evenly ovear all the globe due to the mixing of CO2, and observations show that is what is distinct about the late 20th Century, as opposed to the MWP. What does everyone think? sss

Bristlecone pine data are in one paper (as a very small part) and part of one chapter of the NAS report. All other references I included are not based on bristlecone pines. Note the distinct lack of bristlecone pines in boreholes, glaciers, stalagmites, or Mann et al 2008, namely most of the papers I cited. The weaknesses in the Mann et al methodology have been rectified by subsequent papers using different methodologies and different proxies, with and without tree rings. Mann has been discredited by... who, exactly? Official inquiries by Penn State and the NAS cleared him (see report linked in previous post). Given that his results have been verified independently many times over, and he's been cleared of wrongdoing, you're just plain wrong on that one. Oh, wait, do you want to use the discredited Wegman Report? The one that has a whole host of distortion and plagiarism, as exposed by Deep Climate's articles "Wegman (and Rapp) on tree rings: A divergence problem" and subsequent articles. I'll leave readers to find the article and assess whether they think the Wegman report stands up to scrutiny. Do you have any other official reports that have discredited Mann, Y.S.? On the MWP/LIA, how many times do I have to say that they are perfectly acceptable regional events, most pronounced in the North Atlantic region. Nobody disputes this. I do not, and never have, disputed this. People dispute whether it was global, and there the evidence is doubtful at best. "Warm periods" of various flavours have been identified in many places, but not always at the same time. Such spatio-temporal discrepancies, along with the lack of strong evidence from many non-north Atlantic sites means the MWP cannot be comfortably considered a global event. Jethro asked for evidence to be presented. You can read the NAS report, you can read Wahl and Ammann (2007), which showed McKitrick and Macintyre's results to be "without statistical and climatological merit", and shows Mann's result to be basically sound.

oops by the Sunday Telegraph, caught peddling denier lies... http://www.realclimate.org/index.php/archives/2010/06/leakegate-a-retraction/ They've officially had to retract a story by Jonathan Leake, where he deliberately misrepresented the Amazon non-story and misrepresented one of the scientists involved. The retraction was printed on page 2, but I imagine rather fewer people read the retraction than read (and believed) the original falsehoods. The interesting issue is who edited the story? Leake confirmed with Simon Lewis a reasonable, non-corrupted version of the story a few hours before printing, yet when printed a different story appeared with a completely different slant full of lies and misrepresentations. So was it Leake who edited the story? Monbiot has some ideas, though I wonder if he has much evidence for them: http://www.guardian.co.uk/environment/georgemonbiot/2010/jun/24/sunday-times-amazongate-ipcc Leake has plenty of history of misrepresentation himself though (search Leakegate at Deltoid), and hasn't complained at being hung out to dry by the Telegraph, so the story's probably his... The key thing is that whoever edited the story - Leake or someone else - turned what would have been a reasonably honest one into something distorted and dishonest, which then spread like a virus round the Web - see this list at Deltoid for some of those that followed it: http://scienceblogs.com/deltoid/2010/06/leakegate_corrections_needed_f.php sss

Yep, global sea ice area is clearly trending negative over the past decade, thanks 4wd for that graph. But there are physical reasons why sea ice in the Antarctic has been relatively high during austral winters, and increasing over the past decade - see this post in Skeptical Science for example, and the multiple peer-reviewed references within: http://www.skeptical...increasing.html and also http://www.nasa.gov/...ic_melting.html But the fundamental issue is not the global sea ice cover in itself, because you then are combining two systems in diametrically opposed seasons, with completely different systems at work. The Antarctic has it's ice located surrounding an ice-covered polar conteinent, with the ice located in a band of stormy ocean and two large embayments, very approxmately 60-80deg S. The Arctic has its ice in an almost enclosed polar ocean basin with a few other embayments and basins around. This ocean is under a completely different set of weather systems, and as the ice is dominantly between 70-90deg N, the sea ice lies within the polar weather systems. Add to that the fact that the Arctic ocean and weather systems play a strong direct role in our weather, being that we live quite close to it, and the decline in Arctic sea ice becomes all the more a big issue. I don't like the concept of turning a big shiny white bit of the NH dark for increasing periods of the Arctic summer. [and you can't do the same to the Antarctic!] http://www.ijis.iarc...aice_extent.htm Well below the previous record for this date, showing no signs of deceleration, and looking in a position to follow (be below? :lol:) the 2007 curve, unless something changes soon. At Cryosphere Today, the north polar animation shows a rather concerning recent widespread increase in colour across large areas of the polar basin - sometimes these areas fade back to darker, healthier colours, but if this is a prelude to widespread ice loss then 2007's extent is well within reach. We'll see soon enough:(. The darker-coloured ice is flowing freely out of the Nares Strait and between Greenland and Spitzbergen - this highlights the two dangers to the ice cover. The key uncertainty is the weatehr patterns - will they, as they are at present, exacerbate the melting, or will they become more conducive to retention of ice? We can only hope they become more conducive to ice retention quickly! http://arctic.atmos....edu/cryosphere/ Here's David Barber's plenary from the recent IPY conference in Oslo, which contains some lovely indications on the state of what was thought to be old multiyear ice (the talk has a load of intros, Barber stats speaking about 12 mins in). Apologies if it's already been posted! http://video.hint.no...sc/?vid=55&ti=4 The discussion on the fracturability of apparently old sea ice floes fits well with the animation G-W posted above. Also, good discussion of what happens with the melt ponds. 4wd, you'll be interested in that given your comment earlier - the ice beneath the melt ponds is thinner, not thicker, than the ice around the melt ponds. sss

Nice update to the area guys. In the spirit of trying to keep to the best peer-reviewed science, with data and original references, and in the spirit of not getting personal, here's some more info on 'hockey sticks': In defence of Mann's work - the 'hockey stick' has been statistically verified by independent parties, and reproduced using different statistical methods. The National Research Council found some minor statistical errors, but also found that they had little bearing on the final result Papers proposing to discredit it (McKitrick/Macintyre/Soon/Baliunas etc) themselves have been discredited for using poor statistical methods among other things (see references below). Books such as the opportunistic 'Hockey Stick Illusion' have no scientific bearing as they are not peer-reviewed in any way, and so merely reflect an opinion. In this case the opinion is wildly off the mark, but the book was clearly written to feed on the media frenzy of the unfounded hackergate allegations. Since several reports (quite apart from a bit of common sense) have shown there to be no substance behind the scientific allegations, it's clear that this particular book is hardly going to stand the test of time). Anyone can write, and publish, a book on aliens, crop circles, global warming and black helicopters... A much better book to read would be the excellent: "Noise: Lies, Damned Lies, and Denial of Global Warming " by statisitician Grant Foster, who not only can debunk many fallacious arguments, but provide you with the logical reasoning as to how to interpret noisy datasets. But of course it's a book, and not subject to the rigours of peer review... Some independent and some non-tree-ring verifications of all or part of the "Hockey Stick": Possibly the most important? Committee on Surface Temperature Reconstructions for the Last 2,000 Years, National Research Council, 2006: Surface Temperature Reconstructions for the Last 2,000 Years, entire report available here: http://www.nap.edu/c...676#description [great detail about different methodologies, reconstructions etc, copious references, and that's only till 2006] Wahl and Amman 2007: Robustness of the Mann, Bradley, Hughes reconstruction of Northern Hemisphere surface temperatures: Examination of criticisms based on the nature and processing of proxy climate evidence. Climatic Change, pdf here: http://www.cgd.ucar....mChange2007.pdf Huang et al, 2000: Temperature trends over the past five centuries reconstructed from borehole temperatures. Nature, pdf here: http://www.ldeo.colu...Nature%2700.pdf Smith et al 2006: Reconstructing hemispheric-scale climates from multiple stalagmite records. International Journal of Climatology, abstract here: http://www.ncdc.noaa.../smith2006.html Oerlemans 2005: Extracting a Climate Signal from 169 Glacier Records. Science, pdf here: http://www.martinkod...10995712675.pdf Mann et al 2008: Proxy-based reconstructions of hemispheric and global surface temperature variations over the past two millennia. PNAS, abstract here: http://www.ncdc.noaa...8/mann2008.html [this one's particularly useful as it takes on board the findings of the reviews regarding the statistical criticisms of Mann et al 1998, No tree rings, so no bristlecone pines here YS!, many more proxies, different stats] Some Mann et al context on the LIA and MWP here: Mann et al, 2009: Global Signatures and Dynamical Origins of the Little Ice Age and Medieval Climate Anomaly. Science, abstract and figures here: http://www.sciencema...t/326/5957/1256 http://www.sciencema...y/326/5957/1256 Quoting John Cook of Skeptical Science on the Mann et al non-controversy: "While many continue to fixate on Mann's early work on proxy records, the science of paleoclimatology has moved on. Since 1999, there have been many independent reconstructions of past temperatures, using a variety of proxy data and a number of different methodologies. All find the same result - that the last few decades are the hottest in the last 500 to 2000 years (depending on how far back the reconstruction goes). " http://www.skeptical...ockey-stick.htm I'll end on a question. Given that Mann and every other respectable palaeoclimatologist happily accepts that the MWP exists, just that they debate whether or not it is a global phenomenon, and given that there are some studies that suggest climate anomalies (both of temperature and rainfall) occurring worldwide (YS refers to one or two), why should we be extra worried if the MWP turns out to be a global, not regional, warm phenomenon? Similarly, why should we all be glad that the best global estimates of climate show relatively little global temperature variation through the MWP/LIA episodes? sss

So what, CB, then the changes in relative insolation would be the driver, not ENSO. Since it's well established that the Sun cannot be the dominant driver (incompatible spatial pattern in the atmosphere), clouds show little response (albeit with relatively large uncertainty), what drives relative insolation, or energy input into the oceans and atmsphere? How about increased CO2? This is ridiculous. You'll be telling me that McLean et al were right, next! Seriously, CB, maybe it isn't worth discussing with you if you don't make sense. TWS, yes, Climate Progress may lean a little farther over to one side, but at least it's supported by evidence. Sure it was cold in Scotland, but despite what had to be about ideal conditions, record temperatures weren't set. That, I find remarkable. And a fairly nondescript day (synoptically) two weeks ago set record May highs in parts of Scotland. But I am of course aware enough that Scotland is not the world, and cold air here came from somewhere, and overall most other regions were warmer than average, as shown in all datasets. You emboldened a statement that actually I'd agree with. And many of those sensitivity estimates are not made with models - notably palaeoclimatic ones. I've yet to see anything much credible that places sensitivity below 1.5C/doubling (Knutti and Hegerl is a good place to start there), 3C is quite likely, and higher sensitivity is estimated by some when looking at Pliocene climate, and cannot exactly be ruled out, unfortunately. http://climateprogress.org/2010/05/17/hurricane-season-record-atlantic-temperatures-hottest-april/ http://climateprogress.org/2010/06/01/record-heat-wave-may/ And the hottest 12-month period in the GISS record. Hmmm, certainly no sign of cooling... If I've avoided questions, it's because of the veritable gish gallop of non-sensical claims that I'm trying to deal with. I fear it's going to be time to fade into the background rather than try and explain the basics to people unwilling to accept some or all of : that CO2 is a greenhouse gas, we're significantly increasing the concentration in forcable amounts, we expect that to cause warming, we're observing the warming, we're observing the greenhouse effect actually happening, the spatial pattern of that warming is distinct to GHGs, and the responses of the cryosphere, biosphere, oceans and atmosphere are essentially exactly what we expect. One last link for now: http://www2.sunysuffolk.edu/mandias/global_warming/index.html Some nice links here from Prof Mandia with explanations as to why it's humans, the role of natural variations, the size and impact of the fossil-fuel-funded denial machine (quite an eye-opener) among a host of other topics. ta ta the noo, happy debating! sss

C-Bob, have a read of: http://www.skeptical...bal-warming.htm You'll see the relative amounts of heat injected into the atmosphere and ocean since 1950. The rest of teh article is instructive reading too. Most anthropogenic warming is going into the ocean, only a little is warming the atmosphere. ENSO does not do that. You're still not showing me a long-term trend in ENSO either, only suggesting what might be, and so no I don't agree with you. http://www.skeptical...ming-going.html An interesting article for those that doubt water vapour feedbacks here (Dessler and Sherwood 2009, in Science), but should be freely available from here: http://geotest.tamu....6/dessler09.pdf sss YS, we agree that in Greenland the MWP was relatively warm. We disagree on ice covering settlements in the LIA, and on a lack of sea ice in the MWP. Both of which you stated, without providing evidence. I provided evidence for the opposite. We also disagree on how to interpret historical records. I'll give you a clue - how do you know they are historical 'facts', especially when they were not written contemporaneously, or pertain to another region of the world? And with respect, you brought up your father, not me. And thanks for putting words into my mouth, I have no wish to see the MWP 'disappear', neither does any other researcher. It was a perfectly sound event if you're a European or a Medieval Greenlander. But that does not mean it's a global event. And I'd put a summary of >1000 records from around the globe over your romantic assertions on that one. Remind me again, just exactly what the climatic significance of a strong global MWP is, by the way? High climate sensitivity in the future, or low climate sensitivity? I know which one I'd prefer. Low climate sensitivity, as shown in the global 'hockey stick', is rather prefereable over high sensitivity, given how much we have perturbed the energy balance of the Earth. But you seem to wish to believe that the MWP was global, and somehow that's a good thing in the context of global warming? :ph34r: You also don't realise that the MWP has nothing to do with the fundamentals of AGW theory... No global warming in 10 years is rubbish and you know it. Apart from my 2nd link above, look at: http://woodfortrees.org/plot/hadcrut3vgl/from:2000/plot/hadcrut3vgl/from:2000/trend/plot/gistemp/from:2000/trend/plot/gistemp/from:2000/plot/uah/from:2000/plot/uah/from:2000/trend See any downward slopes? And yet again I'll post to this excellent guide to the 2000s by Tamino: http://tamino.wordpress.com/2009/12/07/riddle-me-this/ and to: http://tamino.wordpress.com/2009/12/15/how-long/ See any spectacular deviations from our warming trend? [and I'd reiterate that despite the insults flying at me here I'd really like to see that trend going the other way...]

LG - http://climateprogress.org/2010/05/31/newsweeks-stefan-theil-uncertain-science-climate-denier/ Always best to see both sides, and here we see the Newsweek article exposed as rubbish, including the last paragraph. YS - you don't get it (why am I not surprised)... how do you know your source was right? You should read up on how to verify historical data. It's a nice book (I never said it wasn't), but that doesn't automatically make everything in it correct. I'd say my sources are more current than yours, as they are people actively working on Norse Greenland, not somebody who's written a much wider-ranging book of which Greenland is only a small part. I certainly don't need to ask my dad! Farming records in Europe go back to the Medieval, yes, but not in Greenland... Speaking of Roy Spencer: http://tamino.wordpress.com/2008/07/28/spencers-folly/ (in 3 parts) http://scienceblogs.com/deltoid/2010/01/roy_spencer_hides_the_increase.php http://scienceblogs.com/deltoid/2008/05/roy_spencer_says_that_if_you_d.php http://scienceblogs.com/stoat/2008/01/spencer_is_totally_off_his_roc.php http://www.realclimate.org/index.php/archives/2008/05/how-to-cook-a-graph-in-three-easy-lessons/ yikes! Some, ah, "interesting" theories there... C-Bob, how does an internal redistribution of energy lead to a radiative imbalance? By definition, ENSO causes temporary warming and cooling (as observed), but cannot add heat to the system. You're speculating, without evidence (lots of 'ifs'). And if Ruddiman's right, Loutre is wrong on his 'long interstadial' hypothesis with decoupling from CO2, which is beside the point as our forcing has changed the picture entirely, at least in the short term - e.g.: Cochelin et al (2006), Climatic Change. sss

Ah, VP, I think the hangover may have got in the way of your normally excellent numerical skills. I think you're confusing total emissions (your 552GT) with the balance between emissions and absorptions which defines the total concentration and resulting changes. Much of the 552GT is absorbed naturally - and pre-industrial times the carbon cycle was approximately in balance. Anthropogenic emissions are what has produced the great majority (ie nearly all) of the increase in concentration, as the carbon sinks have been unable to keep up with the new carbon sources. Given that this increase in atmospheric CO2 has driven (dominantly, with a small early 20th Century solar component) the temperature rise, and that the Arctic temperature rise is particularly susceptible to enhanced GHGs, most of the 20th/21st Century decline in sea ice is surely attributable to the increase in CO2. [i know you disagree with me on the relative merits of CO2/solar, but that's not for now]. Certainly the value of 5% included in the warming in your calculation should be rather closer to 100%, unless you doubt that the change from 280ppm to 380ppm was nearly all anthropogenic [which I don't think you do!]. EDIT: Just looking back at your calculations, you show a 76% correlation between temperature and sea ice, but when you multiply the 76% by your 2.5%, you're determining how much of that 76% is due to CO2 (how good the relationship is), not how much larger the sea ice cap would be if you removed the CO2. And so if we go on your IPCC figure of 51% of the energy imbalance is due to CO2, approximately all of which is due to anthropogenic input, then CO2 would be responsible directly for ~38% of the relationship between ice and temperature? YS - we know Greenland was warmer in the Medieval than the early 20th Century, ditto Iceland. But there has been a lot of warming since then (!). And do you know that what you quote Brian Fagan it's not the original source? Most of the assertions you quote from Fagan are not easily supported by evidence, and quotes from sagas, often written >200 years after the events are notoriously unreliable. Fagan is also at liberty in his book to interpret the evidence in which way he will, but it does not make him the last word on the subject. Hence we can say that it was probably warmer/better weather in Norse times, but we cannot say by how much, or assess the veracity of statements about crops etc, unless we have corroborating historical, or more importantly, archaeological data. Do you have original sources for your quotes? The reason I got at you was because you were making comments about 'no ice', and then 'ice covering settlements', which were wrong. I'm not disputing the presence of the MWP in Greenland, but will happily dispute the climatic extinction of the Norse, for which there is no direct evidence. sss