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Comments 115701 to 115750:

115701. robert way at 13:20 PM on 6 July 2010
        Archibald’s take on world temperatures
        Grace satellite measurements have been affirmed by radar interferometry, laser altimetry and melt modeling. Like I said, a post will be coming and this will be set straight because there are far too many people who are commenting without knowing the basics of glaciology. Ice loss (ablation) in antarctica is 90% through calving and NOT surface melting. Calving is caused by completely different mechanisms than surface melt which dominates the greenland signal (although recent measurements indicate that calving is taking over). In antarctica, glaciers accelerate and thin which causes more ice loss. Once again, I understand the dynamical nature of the west antarctic ice sheet and of other submarine basins in antarctica, but far too many people confuse melt with ice loss... nevertheless, i should have been more clear I guess.
115702. scaddenp at 12:58 PM on 6 July 2010
        Archibald’s take on world temperatures
        rway024 can answer for himself, but I believe he means by "melt" is melting due to overly warm air temperatures and/or rain onto ice. Ice loss can be by direct melt (more important in Greenland) or by calving into a warm ocean (more important in antarctic). At least that is my take. Roy, I think you have been taken in by some skeptic site as virtually all those statement are wrong. eg "The test of math models is whether they work reliably. Observed data is below the model error bounds, so the models are wrong. " Pardon? Doesn't fit with this. Perhaps you point us to papers that support your assertions?
115703. Riduna at 12:32 PM on 6 July 2010
        Archibald’s take on world temperatures
        rway024 at 26 Am I misunderstanding your claim that ..Melting is basically irrelevant in Antarctica and important in Greenland .. If GRACE satellite measurements are to be believed, ice loss in the Antarctic, particularly from WAIS is not only significant but has the potential to be disastrous. WAIS, being a marine ice sheet is particularly vulnerable to attack from warm ocean currents causing large areas of ice resting on the seabed to float. Hardly irrelevant where rising sea-levels are concerned.
115704. robert way at 11:25 AM on 6 July 2010
        Archibald’s take on world temperatures
        previous post was to Roy Latham at 04:35 AM on 6 July, 2010
115705. robert way at 11:25 AM on 6 July 2010
        Archibald’s take on world temperatures
        There is indeed a relation between temperatures and the AMO which results in positive phases having more warming in the north pole and negative phases having more warming in the south pole. This is shown in a recent paper Chylek et al. 2010. Pertaining to your comment about the IPCC’s statements on ice caps, I first have to point out that Ice Caps and ice sheets are not the same thing. Secondly the IPCC statement on Ice Sheets was wrong, and recent studies have shown that the IPCC was far too cautious in their assessments of Ice Sheets. They completely ignored dynamical ice processes. Finally your last point, there will be a blog post on here soon pertaining to the statement but to summarize. Antarctic ice losses are caused only 10% by melting and the rest is due to bottom melting from increased sea temperatures and increased glacier flow rates. You should stop listening to Goddard over there at WUWT about this stuff. He doesn’t have a clue about glaciology. It was shown time and time again in the comments after his post on grace. Melting is basically irrelevant in Antarctica and important in Greenland. Different places, different processes. Don’t get confused by the rhetoric.
115706. Bern at 11:16 AM on 6 July 2010
        Archibald’s take on world temperatures
        Humanity Rules @ #8: You're absolutely right, there is something significant about the 1970s:

        Governments have made efforts since the 1970s to reduce the production of sulfur dioxide into the atmosphere

        (from Wikipedia) I'm sure I don't need to remind you that sulfur dioxide is an aerosol, with relatively short residence time in the atmosphere, which reduces solar input to the surface, and has a cooling effect?
115707. Riduna at 10:32 AM on 6 July 2010
        Archibald’s take on world temperatures
        Esop – 7 As you point out, the highest global temperatures have been recorded during a low period in the solar cycle. What should concern everyone is the effects that more pronounced solar activity will have on global temps. Presumably Archibald thinks that the measurements provided by satellites such as GRACE are wrong? Archibald’s claims of a cooling world really are at odds with empirical data and do little more than repeat assertions made by such luminaries as Lord Monckton and Ian Plimer. One wonders why they make claims which are so easily shown to be wrong?
115708. Riccardo at 10:15 AM on 6 July 2010
        CO2 is Good for Plants: Another Red Herring in the Climate Change Debate
        johnd, real life is different from a controlled experiment. It's already difficult enough to assess the effect in controlled experiment at CO2 concentration more than double current value to think that it should have already be noticed in managed (hyper-fertilized) farms.
115709. johnd at 10:00 AM on 6 July 2010
        CO2 is Good for Plants: Another Red Herring in the Climate Change Debate
        Riccardo at 09:17 AM, I wasn't meaning extrapolating backwards, but to what has shown up in actual observations within the natural environment. The study of plant growth is not a new science. CO2 began it's upward trend over 100 years ago and has accelerated in recent decades. If any short term effects from increased CO2 fertilisation disappear after a few years, then such effects should have been readily observable long ago in any studies of plant growth, as well as in the horticultural industry where it has been practiced for decades. It would also mean that current experiments should see an immediate decreased response to growth, but even in the experiment cited, that apparently was not the case.
115710. ProfMandia at 09:56 AM on 6 July 2010
        Archibald’s take on world temperatures
        Call me crazy, but when somebody asks me what the temperature is I do not look out my window to see if there is snow cover. I check the thermometer. Scott A. Mandia, Professor of Physical Sciences Selden, NY Global Warming: Man or Myth? My Global Warming Blog Twitter: AGW_Prof "Global Warming Fact of the Day" Facebook Group
115711. Riccardo at 09:17 AM on 6 July 2010
        CO2 is Good for Plants: Another Red Herring in the Climate Change Debate
        johnd, the paper focus on the response to elevated CO2 concentration (720 ppm) in a controlled experiment. I don't think it can be extrapolated backward and in a generic environment.
115712. kdkd at 09:14 AM on 6 July 2010
        Astronomical cycles
        Ken #130 I see you're still having trouble with the validity of your argument. However, you do seem to have some kind of estimate of the measurement uncertainty of the global energy imbalance. There might be some validity to attempt to formally reconcile this information with the sea level rise data, temperature anomaly, glacier melt data, ecosystem changes and any other indicators of global warming in order to see if your argument has any validity. i.e. If there is a coherent and consistent body of knowledge that supports your argument. However, you have been unprepared to do this to date, apart from a spot of numerology (impressionistic and opportunist eyeballing of data with no regard for statistical validity).
115713. daniel at 08:21 AM on 6 July 2010
        Sea level rise is exaggerated
        KR I think you should reconstruct the data from table 1 and include sample 1 like I asked Peter to and you will find that Donnely's data supports my conclusion. The linear fit is quite possibly an undersampling of a higher amplitude trend.
115714. johnd at 08:00 AM on 6 July 2010
        CO2 is Good for Plants: Another Red Herring in the Climate Change Debate
        Riccardo at 22:54 PM, given that CO2 levels began rising over 100 years ago, and as well the introduction of legumes that fix nitrogen into the soil has become part of modern farming practices, if the finding of the study cited are valid, to what extent has the CO2 fertilisation effect been suppressed, and to what extent have C4 plant encroachment occurred in todays environment compared to that before CO2 levels began rising and the widespread introduction of legumes began?
115715. Johngee at 07:25 AM on 6 July 2010
        A Scientific Guide to the 'Skeptics Handbook'
        Hi all. New here :0) Love the booklet. Was wondering about other evidence. Like the increase in co2 correlation with decrease in atmospheric oxygen pointing to the combustion process as source for co2. And also the carbon isotope that points to it's origins from plant take up during photosynthesis and hence released when burned. Pardon my lack of sources. I think I read about them on real climate or a few things I'll considered. I am not a scientist so could these also be explained in your booklet?
        Response: Good points. I cover these (among many) in the human fingerprint on global warming. The reason I don't cover them in the Scientific Guide is because it addresses a very narrow question - is there evidence that more CO2 causes warming? The Skeptics Handbook doesn't question whether humans are the cause of rising CO2 levels so in the interest of keeping the Guide tight and focused, I don't go borrowing trouble :-)
        
115716. Peter Hogarth at 07:02 AM on 6 July 2010
        Archibald’s take on world temperatures
        Roy Latham at 04:35 AM on 6 July, 2010 Global record UAH LT V5.3 May 1995 to May 2010 trend is +0.13 C/decade, almost identical to that of the entire record. Continental USA record RSS TLT V3 entire record (1979 to 2010) trend +0.15 C/decade These are public access direct satellite measurement records. Your statements on this are not supported by the evidence. Arctic sea ice 70 years ago was around 20% greater (mean level) than today, from our best overall publicly accessible records. For Antarctic we have very sparse records for pre 1950s, so your statement is dubious to start with, however whaling records, proxy records, and a few voyages we do have a few records from suggest that Antarctica had significantly higher sea ice levels than today, though no precise figures exist. The rise in maximum or mean Antarctic sea ice over the 1978 to present satellite period is just above borderline significant. The 1972 to 1978 interrupted satellite record shows a drop in maximum extent from a higher value than present. The earlier record has uncertainty attached, but it is the best information we have. None of this is based on modeling. Your statements on this are not supported by evidence. If you have other sources please give them. Time permitting I will provide them for all numbers and statements above.
115717. Peter Hogarth at 06:14 AM on 6 July 2010
        CO2 was higher in the late Ordovician
        Tom_the_Bomb at 04:22 AM on 6 July, 2010 Sorry "well tested" should be "well trusted"! These are the two references that stood out in my memory. Minton 2007 is a good introduction, and explores the difficulties with the standard solar model and young sun model with regard to the very early climate, and Gudel 2007 gives a comprehensive exploration of models and other stars as well as the sun. Hope they are of interest.
115718. JMurphy at 06:13 AM on 6 July 2010
        Archibald’s take on world temperatures
        Roy Latham wrote : For example, there is a global warming trend, but there has not been an observed warming trend in the United States in recent decades Do you have any further information to back up that claim ? Just quickly looking at the NOAA site, I have found a 0.31F/Decade trend since 1990, and a 0.43F/Decade trend since 1980. Try it yourself here. All based on a 1901 to 2000 base period. Do you mean since 2000 ? Here the trend is -0.73F/Decade but surely you don't find that significant ? And that is only one decade - hardly "recent decades".
115719. Neven at 05:56 AM on 6 July 2010
        Arctic Ice Part 2: A Review of Factors Contributing to the Recent Decline in Arctic Ice
        Wonderful stuff, Peter! This will save me so much time.
115720. Jim Eager at 05:45 AM on 6 July 2010
        Archibald’s take on world temperatures
        He probably gets it from the widely disseminated misquoting of Phil Jones.
115721. Peter Hogarth at 05:29 AM on 6 July 2010
        Arctic Ice Part 2: A Review of Factors Contributing to the Recent Decline in Arctic Ice
        Andrew Xnn at 04:23 AM on 6 July, 2010 On wind speed, the mean wind speed could decrease but the standard deviation increase, hence more positive peaks, more maximums. I am not suggesting the wind speed is behaving in this nice statistical way, but illustrating the possibility of both occurring concurrently. I'll try to get the satellite wind speed records to see if they match the re-analysis wind speed data. In terms of behaviour, the difference between summer minimum ice extent and winter maximum extent has also increased, though the mean level and winter levels have both decreased. The minimum ice extent in September is simply when ice growth starts to outpace ice melt. If the Spring melt is enhanced by extra downwelling IR, (ie melt rate increases) there is less to melt in Summer when the sun is up 24/7, all other things being equal. The minimum will still occur around September due to the combination of seasonal factors.
115722. KR at 05:17 AM on 6 July 2010
        Sea level rise is exaggerated
        Daniel - you're apparently missing the point from both Peter and myself. The data points from that paper (core samples) fit a linear trend. There is no evidence from those samples of any higher frequency changes (short term), since if there were short term changes those data points would be extremely unlikely to all fall on a linear fit line. Peter said that quite clearly, so did I. The evidence in that paper supports a linear fit - not a long term linear fit with lots of short term excursions. I think Peter said it better: "If there were short term variations of the magnitude which you suggest between the sparse points then the probability of all of these randomly sampled points fitting any smooth long term curve is small." If a rise such as seen in the last 200 years occurred some time in the remaining 600 years covered by the Donnally paper, those carbon dated sediments would not fall on or near the linear fit line for 1400-1800, especially given an average sampling of 60 years. There is no evidence in the data that supports your assertion of short term variations, and hence none are postulated by Donnelly. If you think that there are, you need to find some evidence for them. There's certainly no such evidence in the Donnally data points. If you don't get that, there's really nothing I can say other than to suggest you find out more about data fitting and evidentiary rules in science.
115723. McCloud at 05:17 AM on 6 July 2010
        We're heading into an ice age
        Question: In the projections shown in Figure 4, it looks like there is an upper limit of about 4 degrees C for the temperature anomaly, even at 5000 Gigatonnes CO2 emission, and only about 2 degrees for 1000 Gton. However, the graph in Figure 2 shows that the temperature anomaly is projected to reach 4 degrees C in just under 100 years, on a more or less exponential path, with no sign of slowing down. Is there or is there not an upper limit to the temperature anomaly given these assumptions about the magnitude of CO2 emissions? How sure can we be that the projections shown are correct, given the chaotic nature of the planet's climate? Question 2: Can climate change result in positive feedback as ocean warming leads to the release of more CO2?
115724. Rob Honeycutt at 05:15 AM on 6 July 2010
        Archibald’s take on world temperatures
        GISS link messed up... GISS
115725. Rob Honeycutt at 05:12 AM on 6 July 2010
        Archibald’s take on world temperatures
        Roy Latham... I'm not sure where you get "no global warming trend in the past 15 years." The data don't seem to support you in this statement. UAH GISS RSS
115726. Peter Hogarth at 05:01 AM on 6 July 2010
        CO2 was higher in the late Ordovician
        Tom_the_Bomb at 04:22 AM on 6 July, 2010 The evidence partly comes from analysis of similar stars to our sun at different stages in their life cycle and well tested physics based models. Stars of a certain mass profile appear to display similar growth and fusion burn and brightness patterns, many have star spot cycle activity similar to our sun. I'll dig out some references.
        Response: How the sun was cooler and how this affects climate is discussed in more detail at CO2 was higher in the past.
        
115727. Roy Latham at 04:35 AM on 6 July 2010
        Archibald’s take on world temperatures
        Archibald seems to be in error on two accounts: North America does not equate to the world and snow pack is a consequence of precipitation amounts as well as the temperature. For example, there is a global warming trend, but there has not been an observed warming trend in the United States in recent decades. Of course, there has not been a global warming trend for the past 15 years. The surface ice in the Arctic melts roughly every 70 years, with the last melt in the 30s, and the one before that around 1880. National Georgraphic Magazine about a year ago had an article that described the oscillation. When sea ice decreases in the Arctic it increases in Antarctic, and that has happened this time as well. Sea ice depends upon the relative warmth ocean currents. As to the ice caps, the last IPCC report claimed that the total land ice is very close to stable. If temperatures are well below zero, warming does not cause melting. In the climate debate, the burden of proof is for advocates to prove that there is a climate crisis. The crisis theory is based entirely upon math models that predict the earth will warm considerably more than the straight physics of carbon dioxide predicts. The test of math models is whether they work reliably. Observed data is below the model error bounds, so the models are wrong. The present task therefore ought to be to find models that work.
115728. Andrew Xnn at 04:23 AM on 6 July 2010
        Arctic Ice Part 2: A Review of Factors Contributing to the Recent Decline in Arctic Ice
        Peter; Thanks for the additional clarification. Apparently, I became confused with the following sentence: “Indeed year on year variations in wind speed correlate well with ice extent changes Ogi 2010b, but what about the longer term?” Understand now that this is in reference to seasonal variations. However, the overall decrease in wind speed with increasing storm activity doesn’t make a lot of sense. Understand that downwelling longwave radiation follows cloud cover. However, the shift in sea ice extent is seasonal and the change In cloud cover appears inconsistent with ice observations. That is the greatest negative ice anomaly over the last 3 years has tended to be in September, while cloud coverage in Summer/Fall is small. So, why are we seeing the largest anomalies right around sunset? My guess is that this is when thicker ice is more prominent as a fraction of the total basin. Perhaps in contrast, during the winter max, thinner ice is a misleading observation.
115729. Tom_the_Bomb at 04:22 AM on 6 July 2010
        CO2 was higher in the late Ordovician
        John, what happened to "the sun being cooler" in this argument? You mention it in the summary box but nowhere at all in the body of the text; instead the argument drifts off into rising and falling CO2 levels, that frankly I'm having a hard time understanding. Where is the evidence for the sun being cooler?
115730. Gillespie at 04:10 AM on 6 July 2010
        Temp record is unreliable
        There are quite a few reasons to believe that the surface temperature record – which shows a warming of approximately 0.6°-0.8°C over the last century (depending on precisely how the warming trend is defined) – is essentially uncontaminated by the effects of urban growth and the Urban Heat Island (UHI) effect. These include that the land, borehole and marine records substantially agree; and the fact that there is little difference between the long-term (1880 to 1998) rural (0.70°C/century) and full set of station temperature trends (actually less at 0.65°C/century). This and other information lead the IPCC to conclude that the UHI effect makes at most a contribution of 0.05°C to the warming observed over the past century. http://www.globalwarmingsurvivalcenter.com
115731. Peter Hogarth at 03:19 AM on 6 July 2010
        Arctic Ice Part 2: A Review of Factors Contributing to the Recent Decline in Arctic Ice
        Andrew Xnn at 01:59 AM on 6 July, 2010 Just to be clear, if ice is thinner or weaker, there is a higher probability of wind causing movement and break up as Arctic ice is floating and potentially mobile. Wind can accelerate loss in melt season when long term warming is driving a long term ice thinning trend. Wind contributed to major ice minimum in 2007, but ice had already thinned significantly. Wind is most likely not the primary driver of ice cover loss, - would you think it probable that wind is a major contributor to permafrost melt, Arctic Ice shelf loss, glacier retreat, or a lengthening melt season? The common factor is mean temperature. Anomalous high winds, (from whatever direction) in the recent past have not meant 2007 like losses, just higher deviation away from the ongoing downward trend. Similarly winds played a role in early 2010 anomalous rapid localised increase in peripheral ice extent. You also missed why cloud cover matters.
115732. Peter Hogarth at 02:22 AM on 6 July 2010
        Arctic Ice Part 2: A Review of Factors Contributing to the Recent Decline in Arctic Ice
        Andrew Xnn at 01:59 AM on 6 July, 2010 No, you have misread (accidentaly I am sure). Wind speed variations do correlate with ice extent variations, but this is "natural" short term variation within a melt/freeze season. Overall, average wind speed shows a reducing trend, despite increased storm activity. Temperature, both air and water, continues to correlate with ice extent, and most probably ice volume, through both surface and bottom melt.
115733. Andrew Xnn at 01:59 AM on 6 July 2010
        Arctic Ice Part 2: A Review of Factors Contributing to the Recent Decline in Arctic Ice
        Okay; Just to summarize: Winter Ice Extent correlated with Oct/Feb surface air temps. Small changes in Summer and Autumn Cloud Cover 5% Decrease/decade in Winter Cloud cover 5% Increase/decade in Spring Cloud cover Sea Ice correlation with atmospheric oscillations have weakened over time. Only wind speed continues to correlate with Sea Ice extent. Progressively less ice is drifting at faster speeds Progressive increase of Inflow of warmer ocean waters from the south. Many thanks for the great post!!!
115734. Peter Hogarth at 01:38 AM on 6 July 2010
        Astronomical cycles
        Ken Lambert at 00:44 AM on 6 July, 2010 For the last time, in the case of trends 9 years is relatively short, trend error is obviously higher than that for 18 years, 7 years is even shorter, trend error higher still, 2 years is shorter still and trend error extremely high, no matter if the individual points are just as "accurate" as any other points. All of the altimeters work on basic (obviously I simplify) absolute two way travel time of radar signals. In terms of data from which to derive an overall trend even a handful of points from a new altimeter adds to the picture from other altimeters, (and yes there are known errors in some of the series) but we have to take all of the points to develop the most meaningful trend. Your continued refusal to accept basic principles of statistical analysis discredits you.
115735. JMurphy at 01:36 AM on 6 July 2010
        Astronomical cycles
        Ken Lambert wrote : Readers might also note the convenience with which you classify time periods as short and long term. 9 years and 7 years are impossibly short term when SLR is down (short term noisy data etc), but when SLR ticks up with Jason 2 over the last 1-2 years - it is 'back on track'. So 7 years data is not long enough for my case, but 1-2 years is 'back on track' and valid for your case. Well, as a reader, I note that I cannot find a quote from chris that states the SLR is 'back on track', but I haven't had a thorough check, so perhaps you could post a link to it to make it easier to find ? I can find, however, this bit from his last post : "There isn’t a huge amount more to be determined from the data Ken. There was a short period (2006-2008ish) where the sea level rise slowed down a bit; the last 18 months or so has seen it return to its trend level. We have to be careful not to attempt to make fundamental interpretations from these instances of short term variability." And that last sentence in particular rather seems to prove you wrong in your assertion. Did you not see that ? What was that about Dunning-Kruger...?
115736. Ken Lambert at 00:44 AM on 6 July 2010
        Astronomical cycles
        Chris #128 I know the Trenberth papers well Chris, so you would do well not to claim I am 'quite wrong' in quoting information from them. Dr Trenberth's 0.9W/sq.m imbalance includes +0.12W/sq.m Solar contribution from IPCC AR4 Fig 2.4. Are you suggesting that this is minus another 0.15W/sq.m giving a negative Solar forcing for the 2004-2008 period?? This is at variance with Dr Trenberth's figure of 16E20 Joules/year which equals 0.11W/sq.m, already accounted in his Table 1 of subject paper. Dr Trenberth started quoting Von Schukmann to Dr Pielke in April this year. BP produced a demolition of the VS OHC chart showing impossible heat flow rates from the bumps in the curve. See: http://www.skepticalscience.com/Understanding-Trenberths-travesty.html#6839 #BP30. Latest Willis information is that deep ocean heat gain is small; possibly 0.1W/sq.m (on top of the geothermal flux of about 0.1W/sq.m which should always be there). So the VS 0.54W/sq.m of deep ocean gain is most probably wrong - way wrong. Which still leaves us with an imbalance of 30-100E20 Joules/year. Readers might also note the convenience with which you classify time periods as short and long term. 9 years and 7 years are impossibly short term when SLR is down (short term noisy data etc), but when SLR ticks up with Jason 2 over the last 1-2 years - it is 'back on track'. So 7 years data is not long enough for my case, but 1-2 years is 'back on track' and valid for your case. Sit your Dunning-Kruger effect on that unsubtle fact.
115737. JMurphy at 00:24 AM on 6 July 2010
        IPCC were wrong about Amazon rainforests
        Baa Humbug wrote : Did you find any benefits JMurphy? or is that a silly question? Knowing the source of the 'audit', and also knowing that the IPCC itself would have thoroughly checked everything before publishing, I have to honestly answer 'No' - to the first question, which isn't a silly question at all. Knowing, also, that anything published by humans is subject to human error, I have no problems acknowledging the minor errors found, especially to do with Himalayan glaciers; and the ones found by the recently released Netherlands Environmental Assessment Agency report. Everything else is just semantics and misunderstandings but I'm sure the IPCC will be making doubly sure of their output from now on, which can only be a good thing. I would also not like to be associated with anything associated with NO CONSENSUS, especially as your audit will be used for political, propaganda and denial purposes. You may well have done it with good intentions but you must also have known how it would be used once completed.
115738. Arkadiusz Semczyszak at 00:13 AM on 6 July 2010
        Archibald’s take on world temperatures
        Archibald, of course, is wrong - we have global warming. It fits perfectly into the process (cycle) of natural changes. Cited work here: Are cold winters in Europe associated with low solar activity? Lockwood et al., 2010.: “The results presented in section allow rejection of the null hypothesis, and hence colder UK winters (relative to the longer-term trend) can therefore be associated with lower open solar flux (and hence with lower solar irradiance and higher cosmic ray flux). A NUMBER OF MECHANISMS ARE POSSIBLE [?! ...]. “Our subsequent studies (not reported here) on solar modulation of various blocking indices have confirmed previous studies, and we stress that this phenomenon is largely restricted to Europe and NOT GLOBAL in extent.” These are really just local mechanisms? No, it was not local, and will not be, warm and cold anomalies Temperature proxy records covering the last two millennia: a tabular and visual overview Ljungqvist, 2009: “The records show an amplitude between maximum and minimum temperatures during the past two millennia on centennial timescales ranging from c. 0.5 to 4°C and averaging c. 1.5–2°C for both high and low latitudes, although these variations are NOT ALWAYS OCCURRING SYNCHRONOUS. Both the Medieval Warm Period, the Little Ice Age and the 20th century warming [...] are CLEARLY VISIBLE in most records ...” High-resolution isotope records of early Holocene rapid climate change from two coeval stalagmites of Katerloch Cave, Austria, Boch et al., 2009: “Our record also shows a distinct climate anomaly around 9.1 kyr, which lasted 70-110 yr and showed a maximum amplitude of 1.0‰, i.e. it had a similar duration and amplitude as the (central) 8.2 kyr event. Compared to the 8.2 kyr event, the 9.1 kyr anomaly shows a more symmetrical structure, but onset and demise still occurred within a few decades only. The different progression of the 8.2 (asymmetrical) and 9.1 kyr anomaly (symmetrical) suggests a fundamental difference in the trigger and/or the response of the climate system. Moreover, both stalagmites show evidence of a climate anomaly around 10.0 kyr, which was of comparable magnitude to the two subsequent events. Using a well constrained modern calibration between air temperature and δ18O of precipitation for the study area and cave monitoring data (confirming speleothem deposition in Katerloch reflecting cave air temperature), a maximum cooling by ca 3°C can be inferred at 8.2 and 9.1 kyr, which is similar to other estimates, e.g., from Lake Ammersee north of the Alps.” Once again, Lockwood (and underestimated here: mechanisms): “This grand solar maximum has persisted for longer than most previous examples in the cosmogenic isotope record and is expected to end soon.” “... ~ 8% chance that the Sun could return to Maunder minimum CONDITIONS within the next 50 years. The connections reported here indicate that, despite hemispheric warming, Europe could well experience more frequent cold winters than during recent decades.” 8% - too small?
115739. Johnny Vector at 23:48 PM on 5 July 2010
        Archibald’s take on world temperatures
        Also note how the snow cover graph is presented with the y axis starting at 35 million km². Which is okay if you're concentrating on anomalies, except... He draws it as a bar graph. A bar graph is used to convey information by means of the relative areas of the bars, and as such must start the y axis at zero to give the correct impression. Looking at that graph makes it seem that the snow cover in 09-10 was twice the average. A line graph, or a bar graph with zero shown, would not give that incorrect impression. The difference right there, between damned lies and statistics.
115740. Peter Hogarth at 23:46 PM on 5 July 2010
        Arctic Ice Part 2: A Review of Factors Contributing to the Recent Decline in Arctic Ice
        Arkadiusz Semczyszak at 21:40 PM on 5 July, 2010 It is unlikely that you have read all of the references (yet) but this is forgivable. To then state that I have cherry picked (in the biased sense you mean) I find truly amazing, when you select three references, two of which appear to contradict each other even in your brief quotes in the comment? The irony may amuse any rational observer. However, genuine thanks for these, I will read them with an open mind and get back to you on these specifically. Papers which propose alternative explanations I usually find interesting. To provide links would be nice. On the article, I believe I have taken a fair slice of what is out there, more a shake of the tree than "picking" anything. It is true that I selected references from an even wider pool, but I can say with honesty that of the two hundred or more recent papers that I looked at and could have used, these are the most accessible, and the least dependent on pure modelling approaches. It is possible (and probable) that I have missed many, but this was not due to any conscious bias. In my opinion your comment about "the truth" does reveal bias. "Weight of evidence" allows for uncertainty, "truth", in your sense, does not. I have used plenty of AO references, and references for direct Arctic sunlight measurements and dimming/ brightening short wave trends, long wave trends, wind etc etc. You specifically mention AO, how do you explain the fact that the temperature and melting have continued on what now appears to be an accelerating trend through a century of AO index variations? The correlation of temperature and SLP holds well from roughly 1950 to 2000 (a long time in climate trend terms), but appears to break down before and after this. Factors driving AO can modulate the regional temp and background melt rate, but appear unlikely to themselves drive the longer term trend based on the wider evidence. I am open to new data on this, as I am accumulating references on early instrumental work.
115741. Tony O at 23:34 PM on 5 July 2010
        Archibald’s take on world temperatures
        I sort of discounted David Archibald when he came up with the "we need 1,000 ppm" CO2 figure.
115742. JMurphy at 23:22 PM on 5 July 2010
        Arctic Ice Part 2: A Review of Factors Contributing to the Recent Decline in Arctic Ice
        Arkadiusz Semczyszak wrote : Extensive literature, but ... still the classic "cherry picking" ... It would be all right if not for the fact that here indicated, that ... ... AO is the dominant determinant of what happens in the Arctic of ice - of course it is indisputable fact ... Therefore, I recommend two very new product literature (they tell the truth about what winter in Europe, N. America and Asia, but add that the most important influence on the AO has a SUN ...): Interesting that you mention 'cherry-picking', 'truth' and 'fact' (twice) when you choose to use three sources, two of which are not as thoroughly peer-reviewed as any given in the article, and only one of which actually tries to claim that it disproves AGW - well, sort of. The first paper is published online on FACTS AND ARTS, a Finnish Internet Publication who "offer professional providers of high-quality material direct access to a worldwide, well-educated audience." All very noble but hardly in the same league as The American Meteorological Society or Geophysical Research Letters, for example, and yet you choose to pick it and claim it as being the 'truth' and 'fact'. Here is the link. The comment you refer to is a reply to an online comment from a fan of the article. Again, you chose to highlight it. As for the Lockwood paper, you may have missed this part of it : We stress that this is a regional and seasonal effect relating to European winters and not a global effect. Average solar activity has declined rapidly since 1985 and cosmogenic isotopes suggest an 8% chance of a return to Maunder minimum conditions within the next 50 years (Lockwood 2010 Proc. R. Soc. A 466 303–29): the results presented here indicate that, despite hemispheric warming, the UK and Europe could experience more cold winters than during recent decades. Lockwood is also on record as saying : "This year's winter in the UK has been the 14th coldest in the last 160 years and yet the global average temperature for the same period has been the 5th highest. We have discovered that this kind of anomaly is Significantly more common when solar activity is low." Your final paper is also less certain than you think : We suggest that the most direct driver of the late-Holocene anomalies has been changes in the dominant atmospheric Circulation type. This seems likely in an area, where the modern temperature and precipitation values are highly variable depending on the changing circulation patterns. The anticyclonic circulation type, Currently associated with the highest summer temperature, is a strong candidate as the mechanism behind the warm and dry late-Holocene anomalies. A more detailed analysis of the links between the reconstructed temperature patterns, inferred circulation changes, and the key late-Holocene forcing factors, such as the variability in ocean surface temperatures, solar irradiance, aerosols, greenhouse gas concentrations, and more complex combinations of these and other forcings, requires a more coherent analysis involving model experiments and will be a major palaeoclimatological task in the future. This also appeared in a less-conventional peer-review process (Climate of the Past) than normal : The process of peer-review and Publication in the interactive scientific journal Climate of the Past (CP) differs from traditional scientific journals. It is a two-stage process involving the scientific discussion forum Climate of the Past Discussions (CPD), and it has been designed to use the full potential of the internet to foster scientific discussion and enable rapid publication of scientific papers. All very noble again, and yet, again, you preferred it to any other paper, even though it says nothing that is that controversial - except you tried to higlight just one part of it. Why do you prefer to pick and choose the papers you like ? Why do you use words like 'truth' and 'fact' and yet don't back up those words ? Why, in fact, do you prefer to believe anything but AGW ?
115743. tobyjoyce at 23:09 PM on 5 July 2010
        Arctic Ice Part 2: A Review of Factors Contributing to the Recent Decline in Arctic Ice
        Arkadiusz Semczyszak @5 I followed up on these papers. These are a bit disapponting. (1) The Ahlbeck paper is a local study of AO effects at Turku, Finland, a city on the Baltic Sea, not the Arctic Ocean. (2) I need only quote from Lockwood et al : "We stress that this is a regional and seasonal effect relating to European winters and not a global effect" (3) I was unable to obtain anything more than the abstract of the Seppa paper, but it applies clearly only to Northern Europe, not the Arctic. These seem to me to be insufficient to cast any doubt on the papers quoted in the post, or to justify the accusation of "cherry picking". They are clearly dealing with different topics.
115744. Riccardo at 22:54 PM on 5 July 2010
        CO2 is Good for Plants: Another Red Herring in the Climate Change Debate
        As expected by many, in this case also there's not just CO2, other limiting factors may come into play. And they may depend on the particular specie under study. A new study published in Nature (Langley et al. 2010, paywalled) shows a CO2 fertilization effect on C3 sedge and C4 grasses only in the first year. Supplying N together with CO2 "strongly promotes the encroachment of C4 plant species that respond less strongly to elevated CO2 concentrations. Overall, we found that the observed shift in the plant community composition ultimately suppresses the CO2-stimulation of plant productivity by the third and fourth years." More generally, one may think that profound changes in the ecosystem might be produced by changing atmospheric (and/or soil) chemical composition. Adding changes in temperature and precipitations it's easy to envisage hard times ahead for the Earth System Models.
115745. Esop at 22:33 PM on 5 July 2010
        Archibald’s take on world temperatures
        #10: The El Nino is of course contributing to the temperatures these days, but it is interesting to see that a mild El Nino is enough to completely eclipse the cooling effect of the deepest solar minimum in more than a century, not just that, but we are setting all time temperature records as well. Quite the opposite of the Maunder minumum like conditions predicted by "skeptics" only 16 months ago.
115746. greenhousegaseous at 22:17 PM on 5 July 2010
        Climate cartoon: when positive is a negative
        It isn't a matter of being "politically correct", but of trying to improve our collective (so far) dismal track record of explaining climate science to a largely ignorant voting public. My background is econometric modeling as well as engineering, but I would be happy to help develop *any* alternative verbal (or conceptual) constructs that can help reduce the present confusion regarding climate change, and climate change modeling in particular. Those of us with specialized technical backgrounds all too often demand the general public first accept our often arcane terminology before being permitted to share our knowledge. Then we resent the mass media for misrepresenting the science. The cartoon is therefore right to call our attention to one of the most common examples of unintentional modeling obfuscation. We desperately need to clarify all this stuff in a way that helps the voters of the advanced democracies get behind greenhouse gas reduction programs. You can lead a bunch of horses to a drying water hole, but you can't make them think. Greenhouse Gaseous
115747. skywatcher at 22:02 PM on 5 July 2010
        Archibald’s take on world temperatures
        HR @ #6: The point wasn't that the 24.6m sq km was particularly unusual - it wasn't, and was reported as only the 13th lowest [unusual, maybe but not near record-setting]. The point was that this data is utterly in contradiction to what Archibald was pretending it might mean. We've actually got low snowcover, but by some clever cherry-picking, Archibald can pretend it's high. Winter snowcover is on the whole not temperature-driven, while the summer snowmelt is, as mspelto points out above, so concentrating on winter snowcover tells you more about the precipitation events that dumped the snow. Result - they were unusually high. Reason - increased water vapour due to greenhouse warming?
115748. Arkadiusz Semczyszak at 21:40 PM on 5 July 2010
        Arctic Ice Part 2: A Review of Factors Contributing to the Recent Decline in Arctic Ice
        Extensive literature, but ... still the classic "cherry picking" ... It would be all right if not for the fact that here indicated, that ... ... AO is the dominant determinant of what happens in the Arctic of ice - of course it is indisputable fact ... Therefore, I recommend two very new product literature (they tell the truth about what winter in Europe, N. America and Asia, but add that the most important influence on the AO has a SUN ...): Future low solar activity periods may cause extremely cold winters in North America, Europe and Russia, Ahlbeck, 2010; (“In this report I analyzed the statistical relation between the Quasi-Biennial Oscillation index (QBO is a measure of the direction and strength of the stratospheric wind in the Tropics), the solar activity, and the Arctic Oscillation index and obtained a statistically significant regression equation.”) ... and comment by the author: “But people who do not believe in the ability of the sun to change the climate significantly (in this case the winter weather south of 65. deg.) should know that the influence of solar activity on the winter temperature is statistically significant, which cannot be shown at all for the carbon dioxide concentration. All runs I did with atm. carbon dioxide concentration as independent variable resulted in elimination of this variable as STATISTICALLY INSIGNIFICANT. [...]" Are cold winters in Europe associated with low solar activity? Lockwood et al., 2010 (one of the co-authors: Solanki). Wider context of the role of the SUN is best seen here: Last nine-thousand years of temperature variability in Northern Europe, Seppä et al., (2009).: “The colder (warmer) anomalies are associated with increased (decreased) humidity over the Northern European mainland, consistent with the modern high correlation between cold (warm) and humid (dry) modes of summer weather in the region. A comparison with the key proxy records reflecting the main forcing factors does not support the hypothesis that solar variability is the cause of the late-Holocene centennial-scale temperature changes. We suggest that the reconstructed anomalies are typical of Northern Europe and their occurrence may be related to the oceanic and atmospheric circulation variability in the North Atlantic–North-European region.”
115749. Riccardo at 21:36 PM on 5 July 2010
        Archibald’s take on world temperatures
        HumanityRules, from the data you can determine if a change is statistically significant or not, there's no such thing as absolute "too much" or "not that much". You can also determine the minimum period of observations (or number of observations) for a given variability to get significant results. A tiny few percent of decrease per year may appear to be small, but in 100 years you're left with a few percent of the initial value. So the problem is how far you're looking.
115750. neilrieck at 21:17 PM on 5 July 2010
        Climate cartoon: when positive is a negative
        I hope we're not getting too politically correct in our terminology. The phrases "positive feedback" and "negative feedback" were first used by engineers in the 1930's who were developing amplifiers for the national telephone system. http://en.wikipedia.org/wiki/Positive_feedback#In_electronics As a rule, negative feedback is good while positive feedback is bad.

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