sunny starry skies

The NOAA article is interesting, but it merely records changes at the end of the Little Ice Age, where in the Arctic in many regions temperature jumped up quite rapidly around or after 1920. Yet maps of the pack ice in the 1930s/1940s still show a large and stable permanent pack up there. Note how far north the ships were able to sail (81deg, 29', a "record") - according to MODIS imagery this has been approximately possible in 2010 more or less continuously since early May, and also for much of the 2009 summer, especially later on towards August/Sept. This is another example of how events that were remarkable and unprecedented in previous Arctic history are now commonplace. Submarines surfacing in polynyas don't alter that! Some interesting info regarding USS Nautilus Arctic trips here, made around 1959: http://www.nautilus571.com/Fact%20Sheet.html 9: Polar ice is on average 12 feet thick, although some ridges extend down 50 feet or even further. 26: Ice in the Arctic Ocean is constantly in motion due to the ocean currents and the wind. Water openings are always present even in the dead of winter although unbroken ice sometimes stretches for 10 or more miles. Something else remarkable is how we've got to the 2nd lowest extent on record with weather conditions unfavourable for either melt or ice export over the last month and a half, another large melt reported today...

Return periods are a reasonable tool for analysis, but they are merely an extension of a proper statistical analysis of the data. It's not hearsay to understand that many more high temperature records are being broken than low temperature records - it's a matter of record. Your '1-in-a-100 year flood' examples above provide another point: Imagine the 1236, 1287 and 1953 events were the only events of their kind on record (I agree that the 13th Century events sound far more like 1953 than 1987). That would be 3 events in 800 years, or 1-in-266 years [before anyone jumps on me I'm not suggesting these are the only events of this kind, it's just an example!]. So even though two of the events occurred inside a century, the average return period is actually much longer than a century. More generally, I agree that 1953-like events are not due to AGW and are the right combination of low pressure track, intensity and high tide, though in the medium term higher sea level will eventually make 1953-like events more likely to cause damage. Events such as Russia's heatwave or exceptional floods such as in Pakistan, or Tennessee earlier this year, are expected as a direct consequence of higher temperatures and more water vapour in the atmosphere now. To test this, we should observe a reduction in the return periods for various measures of high temperature or precipitation in susceptible regions, namely high temperatures vs low, and moderate as well as extreme flood events. http://climateprogress.org/2010/08/09/russia-heat-wave-one-thousand-years-global-warming/ http://climateprogress.org/2010/05/26/nashville-katrina-tennessee-superstorm-1000-year-flood/ Easterling's 2000 paper is of good use, though the data and references are now quite old: http://www.nersc.no/~dagjs/rcourse_nzu/Papers/easterling_etal_climateextremes_science_2000.pdf UK increases in extreme precipitation, 1961-2000: http://www.staff.newcastle.ac.uk/h.j.fowler/2003IJC_regfreqanalysis.pdf Papers such as this might be of use (Switzerland precipitation), though I've not read past the abstract: http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V6C-4X6MT39-4&_user=10&_coverDate=02%2F05%2F2010&_rdoc=1&_fmt=high&_orig=search&_sort=d&_docanchor=&view=c&_searchStrId=1426311223&_rerunOrigin=google&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=3ce708a090f674470a09ed8f3700cac3 The point is that we can get hung up on the "it could just be unusual weather", but there are ways of empirically identifying and quantifying the trends. Attribution is a different question, NCDC's "State of the Climate 2009" released last month is not a bad place to start for that. sss

Frequency of extremes is a measurable property though. In a given stable temperature/precipitation record, you expect to see roughly the same number of record maxima and record minima. Over time, you would also expect that the total number of record maxima/minima would decline with time as it gets harder and harder to beat the highest/lowest extreme value. This is not the case with a temperature/precipitation record that is recording a trend. In such a case you expect the number of record maxima to significantly outnumber the number of record minima. This is what is being observed worldwide: http://www.ucar.edu/news/releases/2009/maxmin.jsp http://climateprogress.org/2010/07/05/heat-wave-global-warming/ http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=1569&tstamp=#commenttop For example, the Jeff Masters comment has 17 national high temperature records broken in 2010 up to 6th Aug, and only one low temperature record broken. The cold snap of last winter broke no national low temperature records in Europe or the USA. It brought some record snowfalls, which are entirely to be expected in an atmosphere with more water vapour and energy to play with. Now we can all kid ourselves that the collection of events that have been considered unprecedented (such as Russian heat, Pakistan floods, US floods and heat, etc etc) are happening by chance, but the statistical analysis for temperature extremes shows the trend, and the exceptional precipitation events, wildfires etc are entirely consistent with predictions in a warmer world. If we have all this with 0.8C warming, where will 2-4C take us? Meanwhile the major national media outlets such as the BBC steadfastly refuse to make the connection between the extreme weather and anthropogenic global warming. At some stage, people will have to wake up to the fact that increased frequency of extreme weather such as that we are seeing is not only a prediction of global warming, it is also the principal immediate manifestation of that warming.

Or- G-W, as at least some researchers think, the La Nina feeds into the -ve PDO spatial pattern, ie ENSO drives PDO. But as we've just had a fairly strong El Nino, will that also influence the PDO pattern? We do not have enough data to claim that the PDO spatial oscillation is a regular cycle either, and before predicting it's future state, we need to understand what causes it. Were it truly cyclical, you would expect to have seen a strong negative phase in data before ~1920, but it's not there in the JISAO data (positive if anything between 1900 and 1920. What's to say we're not having another episode of roughly neutral PDO with short periods of negative and positive, albeit the -ve and +ve episodes are of larger magnitude? But all this spatial variability does not hide the fact that the North Pacific has warmed in line with global temperatures throughout the 20th Century, whatever the phase of the PDO.

Hi V.P. - just caught up on the weekend discussions. So far as I can see the NASA paper was talking about land ice mass balance (Greenland and Antarctic Ice Sheets), which are declining and certainly in the case of Greenland, the decline is accelerating. The NSIDC link was comparing the sea ice extents near both poles and describing their differences - Arctic significantly declining (and apparently accelerating), Antarctic sea ice slightly increasing in extent. The NASA and NSIDC points are not mutually exclusive, and Dev has pointed to some good mechanisms whereby Antarctic sea ice might increase in a warming world. When talking about total ice mass, to me you need to separate sea ice from land ice as they are governed by separate processes, and ditto northern and southern ice masses. Antarctica's sea ice increase would not be the first time this year that people on the internet have been fooled into thinking warmer climate must equal universally less snow/ice... Rumours of the demise of this thread are a tad premature - we're still over a month from the average end fo the melt season. 2010 looks increasingly liike 2009, just following the IJIS graph, but as NaDamantaSam has pointed out the weather forecast may be on the turn towards conditions conducive to extent loss. In which case, will we follow the 2008 curve? With volumes perilously low, will 2010 have any other surprises in store? sss

Mars in August... is very faint and low in the western sky not too far from Venus. Mars in August 2003 was bright and impressive, but hardly like the Moon! Here's a shot from where I was around the closest approach in our lifetimes - Frogesque you reminded me with the aurora, there's Mars, northern lights (near the southern horizon) and a couple of small glaciers from 66 degrees north in Iceland. Uranus even makes a cameo appearance as a virtually invisible speck/trail to Mars' upper right. No red aurora that night (28th) or the previous night though for me: sss

This is worth a re-read: http://bobtisdale.bl...do-revised.html PDO: A spatial pattern not related to the absolute temperature of the North Pacific. There is also no clear indication of a 60-year cyclical pattern in PDO: http://bobtisdale.bl...ic-decadal.html From this it seems reasonable to say that there is nothing within the palaeo record that says we are definitely going to have 30 years of -ve PDO. It may indeed be dependent on how many El Ninos or La Ninas we have. PDO can be seen as an aggregated result of ENSO variations - ie - more La Ninas = negative PDO, more EL Ninos = positive PDO. And ENSO is accounted for in global temperatures as driving much of the variability about the rising trend. An additional point - VP could comment more here, but I would say you can't define a cyclical pattern in data with less than 2 'cycles' within it (e.g. the Washington PDO index). You could call it 'pseudocyclical' or something wooly like that, but I certainly would not bet my house on 20 years of -ve PDO. And whatever the pseudocyclicity of the phenomenon, the surface ocean temperatures within the PDO region are rising in line with the rest of the globe. NDS - very interesting, and worrying, analysis of weather patterns there. How much damage could 2 weeks of compaction do to extent figures? sss

And unique fingerprints ae the key issue here, whether they be the isotope of carbon involved, or the spatial and temporal pattern of observed warming (more warming in winter/night, cooling stratosphere), and the wavelengths at which the heat is being trapped (GHG wavelengths). People can argue all they like about whether it's warmed before, or whether it's been X degrees warmer at Y time in the past, but they repeatedly fail to identify the drivers for warming that can explain the observations. It's simply not an adequate excuse to say "it's warmed before", then cite mechanisms that don't fit the fingerprint of observations. It comes down to Mark Serreze's comment in his email to you G-W (linked in Arctic Ice thread) about identifying causes. CO2 has a distinct 'fingerprint', and those fingerprints are all over the current warming. The latest "State of the Climate" report shows this well too. Wegman? There are better sources of information than someone who has been shown to plagiarise and misrepresent in large chunks - see here and links within: http://deepclimate.o...in-full-colour/ http://deepclimate.o...id-done-lately/ John Mashey's take, an update due soon too: http://www.desmogblo...ny%20v1%200.pdf More on fingerprints: http://www.skepticalscience.com/10-Indicators-of-a-Human-Fingerprint-on-Climate-Change.html http://www.skepticalscience.com/More-evidence-than-you-can-shake-a-hockey-stick-at.html sss

Saw nothing either of the past two nights. Once I saw the indices, like kar999 posted, I decided it wasn't even worth a more concerted effort last night. For me in Edinburgh, I reckon you need a Planetary K index of 6 or more to see it, and for the disturbance to be reasonably energetic. I took this photo on 21st January 2005 - the auroral arc was quite high in the sky, but getting progressively more indistinct as the main disturbance had passed earlier in the evening (and I hadn't seen it ). Planetary K index for 9pm-12midnight that night was 6, but had been 8 for the 6 hours before that (probably enough to put aurora just about overhead in Edinburgh). http://www.swpc.noaa...ld_indices.html Also given the sightings from Denmark etc three nights ago (comparable magnetic latitude, but cloudy here), I think we would have seen a similar view with the arc low over the N horizon - planetary K index peaked at 6. I've no other images from Edinburgh showing reasonably quiet aurora that I can check against past index levels to see what level produces a display this far south. The great Oct/Nov 2003 displays were with very high planetary K indices, and aurora to near the southern horizon! Something I do if I think there's activity, and I'm not sure if the glow ia aurora, is take a photo of the northern sky with a digital camera capable of a long exposure (5-15 secs, enough to bring out the stars). Most aurora is a very particular colour of green - if you see that green in the photo, then it's definitely aurora - yellow-orange is probably streetlight glow, blue probably twilight, whitish probably cloud. Your eyes don't see colours well in the dark, so this is a way of removing a little doubt if you're standing around in the cold! sss

Jethro - if the North Atlantic is the source of the water entering the Arctic as Polyakov suggests (I think), what's the current state of the North Atlantic - warm or cool (a genuine question as I don't have the data to hand)? I've yet to see a convincing explanation of quite how a spatial pattern (the PDO) converts into an absolute temperature driver for the globe. When you look at the absolute temperature of the North Pacific region it looks just like the global temperature curve, ie the North Pacific is warming the same way as the rest of the globe. The individual bits of the North Pacific that are warmer or cooler than the basin average swap around - that is the PDO - but the overall basin is warming as elsewhere. How does a warming ocean drive any sort of a cooling? It might temporarily add relatively warmer/cooler surface water into the Arctic, but the last decade of basically neutral conditions has seen the collapse of the Arctic sea ice cap, yet the previous positive phase did not. Is that because, as measured, absolute water temperatures are higher? Lets say we're in PDO neutral territory now - I think we can all agree on that - what was the global temperatures during the last few PDO neutral phases, when (notwithstanding the rather serious issue mentioned above), PDO exerted a comparable influence on climate? Arctic ice extent remains the 2nd lowest ever recorded. Volume is perilously low, with new records set every year. All records from before the 1970s are consistent with a large and stable Arctic ice cap that had been present ever since European explorers tried to travel into it/on it. This is now not the case, and we can't hide from that by looking at photos of surfacing submarines in polynyas. Some interesting Arctic news: NSIDC's July report makes informative reading, projecting Sept extent between 4.13 and 5.27m sq km). Some of the last older,thicker ice is also melting out in the Beaufort Sea: http://nsidc.org/arcticseaicenews/2010/080410.html ARCUS projections have a significant downward revision, mean projection now 4.8m sq km: http://www.arcus.org/search/seaiceoutlook/2010/july For those who like looking at pretty satellite images, Patrick Lockerby has spotted (after predicting a while ago) a huge calving event at Petermann Glacier, which has calved a piece 30km long and up to 15km wide, or 1/4 of it's length from the Greenland Ice Sheet. Calving events happen all the time, but this one's a biggie! http://www.science20.com/chatter_box/arctic_newsflash_petermann_ice_tongue_loses_huge_chunk http://rapidfire.sci.gsfc.nasa.gov/subsets/?subset=Arctic_r03c03.2010217.terra Weather forecasts perhaps trending towards conditions favourable for ice pack contraction next week according to posts on Neven's blog. We'd better hope not, because that pack is primed for compaction. sss

Nice one G-W! Possibly the most important lesson of all in a climate discussion from Mark Serreze there: "Climate does not change all by itself. There must always be a cause. If one is to dismiss it as natural variation, one still has the responsibility of demonstrating the cause of the variation." We have very good reasons for expecting what we observe in the Arctic as a consequence of GHG-induced warming in the context of global warming. The mechanism can explain past changes as well as present changes, and has a sound basis in physics. The same cannot be said of any "natural cycle" hypothesis. sss

Y.S, you have a certain obsession with Mann and North American tree rings. Fortunately Mann (as published, with 1200+ datasets worldwide) does not. Most published reconstructions have the LIA and MWP to some extent, but they all have the 20th Century warming as pronounced, rapid and taking temperatures above those seen in the past. But it is stunningly naive to think that just because we had variation in the past (which is accountable within our best models of climate forcing), that somehow our large forcing of CO2 would not have the large effect that is predicted by basic physics, with amplification that is both predicted and observed, just because climate has changed before. I'm not going to waste my time with your ramblings any more, as you're clearly incapable of a civil debate with someone who dares suggest that your sources of information have significant deficiencies. Spencer, Landscheidt, Taylor and MacIntyre have so many well-documented failings in their research ("research" in the case of Taylor) - I pointed out some of these deficiencies with sources and data to support my points, yet you seem unable to make a sensible assessment of those sources without resorting to shouting. Shouting isn't a very good way to encourage a debating opponent to consider your words worth listening to. Hi Jethro and G-W, the carbon cycle question is an interesting one. So far as I see it, there are a few factors as well as carbon that influence climate on the very long (geological) scale - such as continental configuration, volcanicity and solar brightness. Ultimately it seems reasonable that the influences of each factor on the carbon cycle then drive the climate of the planet. This seems to have successfully explained the major climatic shifts of the past, the generally higher CO2 concentrations of the past (countered by a fainter Sun), snowball/hothouse Earth conditions etc. In many cases the processes of release and long-term storage of carbon are slow, but we can see examples of fairly rapid release at the end of glacial cycles, or associated with the PETM. If current understanding of the carbon cycle is right, we should be able to explain the long-term and short-term changes using similar processes? So far as I can see, we can, and the implication for our currenrt warming is that we are very rapidly releasing a large amount of carbon into the atmosphere, and this will take a long time to be sequestered back into the geological carbon cycle. Whenever large amounts of carbon have been released (whether by a temperature feedback or by an independent process), significant warming has also occurred, such as we are observing now. I haven't seen good evidence to suggest that the carbon cycle should be anything other than the dominant thermostat on the Earth, after the raw brightness (not variability) of the Sun over geological time. sss

Y.S., I find this comment of yours rather ironic: "Try not to dismiss everything that anybody posts because its not to your view. " You do exactly that repeatedly, as well as insulting climate scientists and myself on the way, as you have done in that last post and several previous ones this week. I have provided critiques (some rather detailed and time-consuming) of some of the evidence you have provided, and I am usually met with a barrage of insults and put-downs, rather than reasoned scientific debate (you say you're a scientist - do you act the same way around your colleagues?). For an assessment of Craig Loehle's E&E publication, Rob Honeycutt's review is worth a look. http://www.skepticalscience.com/Kung-fu-Climate.html The key point about Loehle's work, Y.S., is that the series ended in 1935, and that the series were unweighted in any way. Loehle/McCulloch have since published major corrections: http://www.econ.ohio-state.edu/jhm/AGW/Loehle/SupplementaryInfo.pdf which places the MWP similar to the 1930s. We're now ~0.5C above that level. Loehle's corrected study on top of Mann's study: http://farm3.static.flickr.com/2666/3914214320_261cba1cf2_o.png Corrections came about partly as a result of this article at RealClimate: http://www.realclimate.org/index.php/archives/2007/12/past-reconstructions/ Basically Loehle's reconstruction ends up not too dissimilar to many major reconstructions. Spencer's work has been repeatedly criticised both in the literature and elsewhere. His cloud hypothesis does not stand on strong ground, as you would be aware if you'd read some of the papers I've previously linked to. http://www.realclimate.org/index.php/archives/2008/05/how-to-cook-a-graph-in-three-easy-lessons/ A rather different take on Spencer's graphs... I would suggest that you (Y.S.) open your mind to the possibility that the great majority of climate scientists might be right, that cycles do not explain global warming. I trust that your faith in the PDO has prevented you from deriving a temperature reconstruction for the North Pacific, which shows a warming trend very similar to the global warming trend. You repeatedly confuse a spatial pattern of change with absolute temperature change. Of course salmon in California respond to the PDO as they are next to one of the biggest signals of this spatial pattern across the North Pacific - the author of that presentation was concerned with how the frequency of PDO oscillations (if you can call a pattern that is one-and-a-half cycles old a true oscillation) changed in recent years, perhaps due to global warming! What would the case be if you were on an island in the central North Pacific? And have you done that temperature trend graph for UAH yet? Try 1980-2000, then project forwards to 2010. Do the same for any other global temperature proxy, and see what you find. Has global warming stopped? No. Has global warming even slowed down? Nope. Is UAH significantly different to other temperature measures? Nope again. You can verify that yourself, it's not just an assertion from me. woodfortrees.org is useful for this: UAH: http://www.woodfortrees.org/plot/uah/from:1980/to:2011/every:1/plot/uah/from:1979/to:2000/every:1/trend GISTEMP: http://www.woodfortrees.org/plot/gistemp/from:1980/to:2011/every:1/plot/gistemp/from:1979/to:2000/every:1/trend Despite what some say on here I'm quite willing to look at alternative evidence, but so far none presented stands up to scrutiny. sss

Or perhaps not, as the writeup is 10 years out of date, judging by all the graphs and references? It therefore misses the rapid reductions in extent and thickness of the past 10 years. Submarines surfacing in polynyas near the pole prove nothing about the overall extent of thick ice across the pole. We also do not know what the Admiralty was referring to in the 1817 quote - given the many searches for the Northwest Passage, merely getting into the Arctic region was a major challenge, let alone traversing any part of it. There's no record of deep penetration into the polar ice cap here, or evidence of past sea ice conditions remotely like we see today. Back to extent monitoring, and today we see the loss of another ~80,000sq km of ice extent in IJIS data, and a 5-day melt average (of 87,063sq km/day) that is the highest since late June, and the 11th highest of the whole melt season. Extent is the 2nd lowest recorded, witha rapid current melt rate. Cryosphere Today's concentration map shows most of the ice cap away from Greenland/Canadian Archipelago in a bad way too. It now looks unlikely that 2006's extent value is a realistic endpoint, and a 2008-sized large melt takes us to an ice minimum of less than 4,500,000sq km. Now we will see whether this very thin ice in evidence across the pole has any staying power. Something else worth noting is that all this melt since mid-July (average nearly 75,000sq km/day) has been achieved with virtually no ice export out of the Fram Strait. sss

Agreed cooling climate! It's all hype, this time. C-class flares are relatively minor events on the space environment. What will be much more interesting to look out for as activity rises to the next peak are M-Class (10x more powerful than a C-class flare), and X-class flares (10x more powerful than M-class), and proton events as well. During the last cycle there were a number of huge X-class flares and proton events, which produced major geomagnetic storms - they are the ones that worry electronic equipment and power grids. Still nice to see some potential for geomagnetic activity though, shame it was cloudy last night! sss

The Daily Mail actually reported something to do with weather/climate pretty much right!! From the same rag that was going nuts over our cold spell while the world as a whole was remarkably warm in Dec-Feb, and that was spectacularly inaccurate about Phil Jones in Feb. I am gobsmacked and surprisingly impressed. I'm not sure what your problem is with the article Noggin, seeing as it mentions a range of weather extremes, most of them are hot/wet, which is what is to be expected with AGW, and which is what we have seen this year. Maybe there is hope for the media after all...

Y.S. Care to run a trend-line through your much-vaunted UAH dataset? Or do we have to rely on eyeballing? And also check out what Spencer and Christy say about whether we are warming or not (their comments are in the recent ClimateCrocks videos). Conveniently, here's another good analysis, using the HADCRUt3 dataset: http://www.skeptical...ng-Stopped.html It's been often enough shown that the trends in the satellite and surface analyses are virtually identical, so Y.S., why don't you get the UAH data, RSS data, GISS data, or Hadley data, plot it from, say, 1979 to 1995, plot the confidence limits, then add the points from 1996 to 2009, or whatever your favoured time period is? What you find is not only that global warming hasn't "stopped", it hasn't even slowed down, as we're exactly where we would expect to be if you plotted a trend through the 1970s to 1990s! I hope that's useful for folks like Pennine Ten Foot Drifts. The moral of the story is that when purely looking at temperature trends, anything less than about 15 years in annual data and you're looking at the noise, not the signal. There was a great post on that at Tamino's blog but his archive is down at the moment. The same points are made in the Skeptical Science post. The trend for the 2000s is positive, but ENSO over the same period temporarily reduces the trend, especially if you cherry-pick your start date to around the 1998 El Nino. Similar reduced trends have occurred in the past, such as in the 1980s, but did global warming stop then? Over longer time periods ENSO is neutral. The temporary volcanic forcing from Pinatubo is insufficient to make up the difference between the 1990s and the 2000s. And absolutely no evidence from any indicator that our warming trend is reversing - see the NCDC State of the Climate report, for not only the trends but the specifically human fingerprints too. VP - E&E doesn't exactly have a reputation for publishing good science. Its own editor, Sonja Boehmer-Christiansen admits as such: "By the way, E&E is not a science journal and has published IPCC critiques to give a platform critical voices and ‘paradigms’ because of the enormous implications for energy policy, the energy industries and their employees and investors, and for research." http://www.timeshighereducation.co.uk/story.asp?storycode=407763 I would be extremely wary of anything posing as 'science' that is published at E&E, and ask yourself why it has not been published elsewhere. Does the physics proposed stand up to scrutiny? If that was sound science it would easily be published in a journal relating to atmospheric physics, which would be rather more appropriate than one devoted to one aspect of climate politics. sss

There isn't much that is confusing about a pack that has been thinned out to the point that it is highly mobile and susceptible to weather events. It has been thoroughly pre-conditioned to react rapidly to synoptic conditions favourable for ice export and/or in-situ melting, by virtue of its thin and shattered state. Ice extent has reduced with not only a declining trend, but an accelerating trend, entirely consistent with a pack that has lost the cohesiveness it had for all the time that people have explored on it or sailed through it. How many would fancy a trek over thin 1-2 year ice to the North Pole now and hope to keep their feet dry? Dev, 1930s map of Arctic ice summer minimum here: This is summer minimum, so unless you think every single observation that went into the construction of this map is wrong, we can safely conclude there is much less ice up there than 70 years ago. This is amply corroborated by Northwest passage openings (last few years only) and speeds of transit, which have rapidly shortened over the last century. sss

4wd, do you think it's irrelevant if the temperatures are warmer in the winter in the Arctic, and on a warming trend? Do you think that the same amount of ice will form to the same thickness if it's -5C or -25C? Summer temperatures north of 80N are largely irrelevant due to the influence of the latent heat of melting, ie surface temperatures will be close to freezing while the ice is melting. Have we not already discussed this?! sss

It's entertaining the way you rail against my opinions Y.S., when all I've done is provide some evidence for others to go and look at, and reasoning to support my opinion. You call me arrogant among other lovely names, yet I leave it for others to form a judgement! I thought Taylor's presentation was scientifically worthless and provided sources for reasons why. I didn't think much of the report by some lawyers on climate science, because I didn't see them considering the full body of evidence. If you don't like my opinions, dispute my evidence, come up with better evidence! And it's funny how the 'tests' are always just starting? We've been told it's going to cool substantially for the last decade or so and it hasn't, it just got warmer. The last 12 months have been the hottest on record, so it would hardly be surprising if the next 12 months didn't quite hit those heights, but there's no evidence of a cooling trend. La Nina always produces a temporary cooling, or downward variation about the rising trend, so no change there, except that this La Nina won't be as cool as those in the 1990s or 1980s. PDO does nothing overall as it's a measure of a spatial pattern, not of absolute temperature. What was the global mean temperature at each of the last three/four PDO 'neutral' points, ie earlier in the 20th Century? Is there an underlying trend that isn't captured by the PDO? I read an interesting article on RealClimate which notes the 35th anniversary of the coining of the term "global warming" by Wally Broecker in 1975. Some interesting observations on the time at which a 'consensus' could be said to have been reached (1980s to 1995 approximately), and on the scientific position in the 1970s: Broecker (1975) "Are we on the brink of a pronounced global warming?" reviewed at: http://www.realclima...ming/#more-4520 And lest anyone think that this is a science that is a mere 35 years old, here's a paper, dug up by someone on the comments to the above thread, from 1938. Callendar (1938). "The artificial production of Carbon Dioxide and its influence on temperature" http://dl.dropbox.co...callender38.pdf {This isn't exactly "New Research", but it's relevant!} It's almost chilling to read some of Broecker's comments, written at a time when global temperature really had declined for a couple of decades; and in Callendar's paper, to see how the basics of atmospheric physics, and the consequence of adding CO2 to it, were rather well understood 70 years ago, when my grandparents were about my age, or 35 years ago when my parents were close to my age. sss

But surely the dominant drivers of melt are wind export and ocean temperatures, which are not declining? The only thing that is 'saving' the pack this year is synoptics unfavourable for surface melt and wind export. Yet we have record low ice volumes. A 2007-type season would destroy the current pack. I think Arctic monitoring is going to run into a bit of bother because of the reliance on extent as a measure rather than area or volume. Extent (which is area with >15% ice) can be fooled by fragmented, spread-out ice, much as we obviously have this year. Area is slightly better, but clearly does not take into account that the ice is much thinner than it was just a few years ago. Volume measures (bring on Cryosat-2!) are going to be the only thing truly recording Arctic ice decline. Area graph: http://www.ijis.iarc.uaf.edu/seaice/extent/AMSRE_Sea_Ice_Area.png Some more interesting observations here: http://neven1.typepa...xtent.html#more and here: http://tamino.wordpr...-ice-curiosity/ There is really obviously no 'recovery' in Arctic ice - in fact it's quite the opposite when you look at the ice as compared to previous years, but 'extent' measures may not record the fullness of that decline. We may be fooled into thinking we have longer with a polar sea ice cap than we actually do. sss

This UPenn report desn't truly cover both sides, though. It's an attempt at a review of the climate science by people at an Institute for Law and Economics. Assuming they have no axe to grind (frankly a bold assumption given the literature they cite), then the best that can be said of it is that it is a poorly-informed review of the sc ience, highlighting basic issues raised time and again by skeptics, and debunked time and again by scientists. I'll only give one example, as I have not the desire to laboriously critique another paper - they go on about problems with the surface temperature record, highlighting that night-time minima have risen much faster than daytime maxima. They suggest this is problematic because night-time minima may be more sesitive to vertical mixing, therefore the rise in 2m global temperatures might be an artefact. Fair enough.... if that was the only evidence. Satellite evidence, changing dates of flowering, budding etc amongst many others contradicts this point entirely. No mention is made of the fact that higher night-time minima is actually a prediction of the enhanced GHG effect theory, as a consequence of reducing outgoing longwave radiation. So to me, as a review, it's falling at the first hurdle because it is only considering a tiny subset of evidence, not what you need to do when considering a scientific question. Clearly they're looking for 'reasonable doubt', but you cannot find 'reasonable doubt' in a scientific question in the way they are trying. Another gripe - first sentence of the abstract: "Legal scholarship has come to accept as true the various pronouncements of the Intergovernmental Panel on Climate Change (IPCC) and other scientists who have been active in the movement for greenhouse gas (ghg) emission reductions to combat global warming." They appear to be conflating the scientific observations with moves for emissions reductions. The observations need to be (and have been) examined on their own terms. Emissions reductions are a separate issue, as reflected by the IPCC separation of the fields. Very few actively publishing researchers in global warming science have any stake in policies to reduce emissions. Interesting post G-W. It looks like an unconfirmed result as yet, and so in line with what I put forcefully above, I would wait until this evidence is supported before declaring an oceanic disaster. Certainly it's very bad news if this study is correct. NCDC "State of the Climate" for 2009 is out. It's a report which is "drawing on the work of more than 100 scientists from more than 20 institutions" according to the Met Office: http://www.ncdc.noaa.gov/bams-state-of-the-climate/2009.php Some key figures here: http://www.metoffice.gov.uk/corporate/pressoffice/images/soc-obs.gif Interesting observations on climate, heat waves and politics from Peter Sinclair: http://climatecrocks.com/2010/07/29/climate-crock-heat-wave-edition-part-1/ and part 2 here: I like the part where the usual loonies like Inhofe or Monckton claim it's been cooling since 2001. Maybe they need a read of the NCDC report too... sss

Thanks for the kind comments Pete and G-W. I had a spare evening, and thought I should check out what Taylor had to say (it wasn't his book but a presentation, presumably with much of the same material). Y.S., "ill-informed and ignorant"? That's really not a very nice thing to say. If you think so, but I have provided numerous sources with direct and indirect links to many dozens of peer-reviewed studies that show Taylor to be wrong: the feedbacks are perfectly real processes, the cloud uncertainties are fully acknowledged (the feedback may actually be positive, not negative), and there is not much of an observable trend in cloud cover or cosmic rays that relates to temperature. You can read all these sources and see if you still think Taylor's tale is persuasive! If you still think I was being "ill-informed and ignorant", come back and tell me (with references) why all these studies I used to support my points are wrong, don't just call me names. Taylor had a very poor argument, though if you knew little about climate I could see him being persuasive - it shows to me why one can't immediately trust what one reads in an un-reviewed book, or sees in a random video presentation. He's happy to dismiss huge tracts of research in favour of one or two cherry-picked and usually out-of-date studies (yes, scientific studies, I did not pretend otherwise), well that's up to him but it's hardly good scientific practice to ignore all the data that does not agree with your point. Shouting 'FACT', or presenting an eloquent video, or writing a readable book, does not make me want to believe those 'facts' unless they are supported by good quality evidence that has not been rebutted in one way or another. I leave it up to others to judge the evidence for themselves, but there was precious little sound evidence I could find in Taylor's presentation. I'm always on the look-out for good alternative hypotheses, as I'd frankly be utterly delighted to be proven wrong on the state of the climate, but there was nothing of substance here and so the search goes on. sss

My apologies in advance - this is a long post, basically a review of Mr Peter Taylor's presentation as highlighted by Y.S. Taylor is supposed to be a sufficient authority for his book 'Chill' to be a rather revolutionary text on AGW. Apparently, Taylor's arguments on climate are meant to be very persuasive - I set out to check them using Taylor's video presentation. It turns out they have as much substance as one of Christopher Monckton's talks as debunked by John Abraham. It shows classic examples of cherry picking, failure to understand the subject, use of out-dated and subsequently revised research, as well as deliberate falsehoods. I've used a combination of peer-reviewed research, posts from RealClimate and Skeptical Science (both of which are laden with original peer-reviewed sources, and IPCC documents as support for various debunkings. I'm trying to be objective, and not be personal in my criticism, and have tried to provide links to sources where I think Taylor is wrong. Review of Peter Taylor video presentation: Mr Taylor admits he got bored of doing science (several times not finishing courses), and says he's not a scientist. He then quickly places his cards clearly on the table by saying he sees renewables as leading to wind turbines everywhere, forests woodchipped and biofuels everywhere, says that's crazy. My assessment of that is that if you are going to have an opinion on whether the science is right, don't start by complaining about policy choices that may or may not be a consequence of the science (and are not what scientists talk about). "Renewable energy will destroy everything that's beautiful and valuable about our planet". Mr Taylor - that really is not the place to start if talking about the science. Fallacy #1 and #2 (14:00ish): just as he starts talking about the science, he thinks that water vapour and clouds are more important than CO2 and models are wrong: http://www.skeptical...mate-models.htm http://www.skeptical...enhouse-gas.htm http://www.realclima...ack-or-forcing/ Water vapour is, of course, a feedback, not a forcing. The models have been validated numerous times over. Fallacy #3: He thinks the first real talk about global warming was in 1985. Ignoring Arrhenius and other 19th and early 20th Century people who quite clearly saw the issue, by the late 1970s/early 80s there was pretty much a scientific consensus already that CO2 would cause warming, just not about how much. Here's the late, great Stephen Schneider on the subject back in 1979: Schneider 1979: History of the CO2 greenhouse effect: http://www.aip.org/h...climate/co2.htm 1970s view on AGW: http://www.skeptical...ns-in-1970s.htm Fallacy #4: "on it's own, it's [CO2] only a marginal effect? Depends on what you think a 1C change will do. 1C globally is quite a large change given the change between ice age and present is only ~4C. http://www.skeptical...ouse-effect.htm http://www.ipcc.ch/p...s2-3.html#2-3-1 Taylor quotes Richard Lindzen saying in ~1990 that the water vapour feedback might be overridden by a negative cloud feedback. Then claims that the NAS rejected the 2001 IPCC report, leading Bush away from Kyoto. This is demonstrably false: http://www.nap.edu/c...record_id=10139 You can read the report yourself - it endorses the IPCC findings, and Lindzen is one of the authors. A summary of this episode is about a third of the way down this page: http://monthlyreview.org/1001jbf.htm Bush pulled out for economic, not scientific, reasons. Taylor repeats the falsehood that the NAS told the US govt the IPCC report could not be trusted several times. You can read the NAS report yourself. Taylor is demonstrably being economical with the truth. Taylor then claims not to have an agenda against renewable energy. No? What about what he has already said in the presentation? Repeats fallacy of how small the total anthropogenic greenhouse effect is (with disparaging remarks about models) at ~2.5W/sq m (it's actually ~1.6W/sq m), by comparing it to a 60W light bulb, then to the change when a cloud passes in front of the Sun. Disgraceful strawman argument there. The imbalance is quite enough to cause significant warming of the Earth. For example: http://www.ipcc.ch/p...wg1/en/ch2.html http://www.ipcc.ch/p...wg1/en/ch9.html http://www.ipcc.ch/p...figure-9-5.html Then onto the suggestion that clouds are "hardly ever mentioned", and the first place he'd go to look would be models of clouds. How about the observations first, Mr Taylor? Observed changes in cloud cover? That would be where I would look: Many papers here: http://agwobserver.w...d-cover-trends/ Clouds observations in AR4 here: http://www.ipcc.ch/p.../ch3s3-4-3.html He then suggests clouds changes can explain all of global warming (saying conveniently he's 'not a denier of global warming'). But clearly does not believe in the CO2 greenhouse effect if he thinks 2W/sq m forcing is small... All his cloud theories apparently relate to the solar wind. But these hypotheses have been falsified: http://www.skeptical...bal-warming.htm http://www.realclima...inued-interest/ http://www.realclima...mate-relations/ The last link has a series of papers testing cosmic ray hypotheses through Forbrush events, and prove that they do not have an effect on global cloud cover. [Calogovic et al. (2010); Kulmala et al. (2010)] Then Taylor claims it's all cycles, sounding rather like your good self, Y.S. Taylor mentions the 200% enhancing of CO2 forcing {like yourself Y.S.}, but hasn't read the research as outlined in my previous posts, where there are plenty of observations to support feedbacks in models. ISCCP data apparently shows 4% decrease in cloud cover. But he shows the graph for low cloud cover, not total cloud cover, which is misleading. The total cloud amount graph shows a <2% change from the ISCCP site: http://isccp.giss.na...bp.anomdevs.jpg http://www.ipcc.ch/p...h3s3-4-3-2.html ISCCP faulty: http://www.agu.org/p...6GL028083.shtml The discussion in AR4, and various papers in the agwobserver cloud papers page highlight problems with ISCCP data (such as satellite look direction distortions), and other datasets (HIRS) that show opposite trends over the same period. So showing one graph and claiming that it's the dogs b*llocks when it comes to clouds is being distinctly disingenuous to say the least! He mentions global albedo, using a faulty dataset from a faulty method (earthshine), and fails to mention that the results have been disputed, and better measures of albedo show little or no long-term trend, and falsify the earthshine method: http://www.skeptical...bedo-effect.htm [and embedded papers] He then claims to "scientifically conclude" that much more energy has been coming in than going out, due to clouds. If he was right, global warming would already be catastrophic (8W/sq m is a lot of radiative forcing), but he's using cherry-picked datasets that have been falsified many times over to come to his favoured conclusion. That is not scientific. He mentions the much-debunked Friis-Christensen and Lassen 1991 study (repeatedly shown to be completely wrong), then talks about cosmic rays and temperature. A persuasive graph from Svensmark of cosmic ray-cloud connections? No, because the correlation has completely broken down since 1995. There is no relationship that holds between cosmic rays and temperature: http://www.skeptical...bal-warming.htm http://www.realclima...ic-cosmic-rays/ http://www.realclima...in-new-clothes/ EPA findings: http://rabett.blogsp...-svensmark.html I've given up on Taylor's presentation from here on. It's a loose collection of of misunderstandings and falsehoods, where he demonstrably gets nearly every branch of climatology wrong, and cherry-picks old papers and papers subsequently shown to be problematic to push his points. He fails to highlight quality research that contradicts his points, which is poor scientific practice, and not one the IPCC or other academic bodies do. Yet we're supposed to believe that he's right and everybody else is wrong? I don't think so. I believe on this evidence I was right in my assessment of his book as being unsubstantiated and wrong, and this goes to show that people like Taylor with no climate track record, who write books that go through no scientific auditing process, are promoting pseudoscience. I'm sorry to hear you've been taken in by it, I really am, but there's nothing of substance in anything Taylor has said. He's either not read all the relevant research and is thus not sufficiently informed, or he is deliberately misleading his audience. There are no other explanations. Either way it is not a scientific assessment of the research. Another example of a book shown to be wrong on a subject related to climatology here: http://www.realclima...tford-delusion/ The message is, as ever, do not trust what you read in a non-academic book: they can, and regularly are, saying whatever they like, even if it's that pigs can fly. They do not have to undergo a review process, and reflect the author's opinion. If you read a book, or see a presentation like this, always verify the sources and check that the research is up-to-date! sss

No, I'd expect a normal decline. The date of melt start should not affect the rate of summer melting. We got a big decline over this period, with the same Sun elevation over the pack, albeit different melt start dates. Some of April's melt can be attributed to thin ice produced by the late spurt, but not May's or June's. Has there or has there not been a remarkably large melt this year?