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Comments 81951 to 82000:

81951. Dikran Marsupial at 23:18 PM on 20 June 2011
       When scientists take to the streets it’s time to listen up
       ClimateWatcher Taking to the streets is not necessarily an emotional exercise, raising awareness of an issue by public demonstration is perfectly rational behaviour. Science is not the exercise of cold rationality, it has a large imaginative and creative component; oddly enough very few scientists are like Spock from Start Trek. When scientists take to the streets to raise awareness of an important issue, then ignoring it would be irrational. Who better to raise awareness of scientiffic issues in the general public than those who actually know something about the science. Apart from that, I am in complete agreement. ;o)
81952. Eric (skeptic) at 23:05 PM on 20 June 2011
       Linking Extreme Weather and Global Warming
       Tom, your null hypothesis is very reasonable but I have a quibble. How are we going to estimate mean tropical Pacific OHC for the past (i.e. before the 50's) while accounting for ENSO itself? Do you know of studies that do that (my quick search didn't turn up any)?
81953. ClimateWatcher at 22:48 PM on 20 June 2011
       When scientists take to the streets it’s time to listen up
       Taking to the streets is an emotional exercise. Science is an exercise of cold rationality. When scientists take to the streets, it is the activity ( which is not science ) to ignore.
81954. Rob Painting at 22:47 PM on 20 June 2011
       CO2 Currently Rising Faster Than The PETM Extinction Event
       Phil Scadden - whoa.......15 million gigatonnes of organic carbon! Crikey! Are you able to access a copy of the paper? Jerryd - A tutorial would be cool. Maybe you can tee-up with John and we could get something underway?
81955. skywatcher at 22:37 PM on 20 June 2011
       How would a Solar Grand Minimum affect global warming?
       #68: Eric. Can you provide evidence that climate scientists dismiss other potential influences in the way you disparagingly suggest? Because overwhelmingly the science attributes different levels of forcing to different forcing agents, not just CO2. Levels of forcing are strongly discussed, with values and uncertainties gradually converged upon for a wide variety of forcing agents. Maybe some bloggers / internet commentators do, or suggest, otherwise? You'd certainly not find any of the >97% of actively publishing climate scientists, who agree with the consilience of evidence, disagreeing with your statement that "There is nothing simple about changes in the climate." Of course there isn't.
81956. Riccardo at 22:20 PM on 20 June 2011
       Websites for Watching the Arctic Sea Ice Melt
       BC it is known as polar amplification. You may want to start with this post at RealClimate.
       Response:

       [DB] And also this post here at SkS:

       http://www.skepticalscience.com/What-causes-Arctic-amplification.html

81957. Dikran Marsupial at 22:11 PM on 20 June 2011
       When scientists take to the streets it’s time to listen up
       John Russel Looks a sound approach to me. The Svensmark hypothesis is a good example in that Svensmark has been well funded to investigate his hypotheis (e.g. CLOUD project at CERN), and nobody was ridiculing Svensmarks basic hypothesis, the major critcism was of his lack of self-skepticism and tendancy to overstatement. This shows that the scientific community (who would have reviewed his grant proposals) are not afraid of having their paradigm overthrown, but they would require compelling evidence.
81958. John Russell at 22:00 PM on 20 June 2011
       When scientists take to the streets it’s time to listen up
       I've just written the following on a thread on Carbon Brief. [I reference 'Svensmark' only because the commenter to whom I was replying brought up the name.] I'd be interested to know whether I could have expressed anything any better -- bearing in mind that the comment is aimed at the lay person rather than someone who understands the scientific process. I'm just trying to improve my ability to get across the message encapsulated above in the 'Conversation' article. "Please understand that I am not a climate scientist, so rather than come up with my own ideas I rely on the climate scientists to explain what's happening. I've read a lot of what they tell us and it pretty much all makes good sense. The sums stack up and it fits in with my understanding of science. Sure there are uncertainties, occasional errors and ideas will change over time, but the proper way the consensus is modified is by scientists discovering or recording new data which then persuades the mainstream to modify their views. This has been happening for the past 40 years or more as our understanding of Earth's climate has evolved. Whenever a 'maverick scientist' comes along and offers an alternative explanation for what is being observed, then other scientists will study it, test and then it will modify our collective understanding -- or not. I, personally, would be mad to go along with outlying ideas until scientists working in appropriate fields have processed and filtered them and as a result they have changed the consensus view. That's how science works. Believe me, if the Svensmark team come up with something valuable it will change ideas. But it seems to me that you are too anxious to prove that the consensus is wrong and are clutching at contrarian straws. The consensus accommodates the scientifically-strongest theories/beliefs that exist at any point in time. Rest assured; if the consensus proves to be wrong, it will change. Since science began, it always has and it always will. As they say, the truth will out. As non-scientists we have to believe that the consensus as it is at this moment is correct for this moment and behave accordingly. To do otherwise is just crazy. Surely you must see the logic in that?
81959. Eric the Red at 21:37 PM on 20 June 2011
       How would a Solar Grand Minimum affect global warming?
       scaddenp, Here is one article of many. http://www.cdejager.com/wp-content/uploads/2009/02/2009-episodes-jastp-71-194.pdf There is nothing simple about changes in the climate. This is not to say that I believe that CO2 has not infuenced our climate. However, I have read too many people who readily dismiss any other potential influence simply because they cannot attribute the entire warming to it. No one factor has been able to thus far.
81960. BC at 21:27 PM on 20 June 2011
       Websites for Watching the Arctic Sea Ice Melt
       Can anyone explain why the Artic always seems to consistently have such a high temperature anomaly in the world maps, more so than anywhere else? Or maybe there's an article in SkS that explains why?
81961. Eric the Red at 21:20 PM on 20 June 2011
       Linking Extreme Weather and Global Warming
       Paul, Why would we expect an increase in extreme events under global warming? Granted, a warmer atmosphere can hold more water and lead to overall increases in rainfall. Conversely, global warming is expected to lead to lower temperature gradients (this has been observed during the last century). Can we say with any degree of certainty that the increasing water content will outweigh the decreasing temperature differences?
81962. Eric the Red at 21:13 PM on 20 June 2011
       Linking Extreme Weather and Global Warming
       Tom, Nice post. I have also read were places like Mexico and the Sahara were driest during the coldest periods also. With regards to snowfall, the general rule is that the closer to freezing, the more snowfall. This is true for both places that are above and below freezing. In places like Antarctica, the temperatures are always below freezing, so any rise will bring the temperature closer to freezing, and subsequently more snowfall (still very little). The areas of Greenland which average slightly below freezing will also see more snowfall as the temperatures rise. Those regions where temperatures are above freezing for most of the year, will experience mroe snowfall as temperatures fall towards freezing. Single winter snowfall is indeed a crap shoot, depending on the temperature, jet stream, oceans, etc. Unfortunately, some of these single-year events have been used by many people (believers and non-believers like) to attempt to prove their position. One (or two) years does not a trend make. However, over a period of years or decades, subtle changes can be observed, like Antarctica. Thanks.
81963. Arkadiusz Semczyszak at 20:53 PM on 20 June 2011
       CO2 Currently Rising Faster Than The PETM Extinction Event
       The amount of papers on the PETM is actually “huge”, but the latest should not be overlooked. So I am surprised by the lack of work cited by scaddenp. There are interesting observations: “The mass of organic carbon in sedimentary basins amounts to a staggering 1016 t, dwarfing the mass contained in coal, oil, gas and all living systems by ten thousand-fold.” “... only a tiny change in the degree of leakage, particularly if focused through the hydrate cycle, can result in globally significant greenhouse gas emissions.” “Methane degassing from sedimentary basins may be a mechanism to explain increases of atmospheric CO2 to values as much as 20 times higher than pre-industrial values.” But these processes can take place quickly? “As geologic sources may have contributed over one third of global atmospheric methane in pre-industrial time, variability in methane flux from sedimentary basins may have driven global climate not only at time scales of millions of years, but also over geologically short periods of time.” How “short”? Most - perhaps - a "complete" - new - from this year - work on the PETM is a paper: Methane and environmental change during the Paleocene-Eocene thermal maximum (PETM): Modeling the PETM onset as a two-stage event, Carozza, Mysak, and Schmidt, 2011. - A corresponding well with the observations and conclusions of the work cited by scaddenp. So it describes the most likely “the course of events”: “To explain the observations, the carbon must have been released over at most 500 years. The first stage results cannot be associated with any known PETM hypothesis. However, the second stage results are consistent with a methane hydrate source. More than a single source of carbon is required to explain the PETM onset.” “... second stage (stage 2) ...” is therefore particularly interesting. “In particular, for DT = 3°C [Winguth et al., 2010], a mixed emission of 900 to 1400 Pg C consisting of 400 to 500 Pg C CO2 to the ocean and 400 to 900 Pg C CH4 to the atmosphere simulates stage 2. Durations of 50 and 250 years are data‐compatible (Figure 2c); however, only a duration of 50 years is compatible with 3°C of warming.” “Therefore, the emission of 400 to 900 Pg C CH4 to the atmosphere and 400 to 500 Pg C CO2 to the ocean, with a duration of 50 years and d13C ranging from −50 to −60‰, best simulates stage 2 ...” So we have 50 years - the same as for the period 1950 to 2000 AD. During this period the volume of our emissions are on average 5 - 6 Pg C - with the 2.5 - 3 Pg C „to the atmosphere”. For PETM - „stage 2” we have: 400 to 900 Pg C „to the atmosphere” during 50 years = 8 - 18 Pg C year - 1 ... Where else could take on carbon? Rob Painting writes about the permafrost - and His rightly - the organic carbon stocks in permafrost (poor in13C) (and the content changes over time) may be many times greater than we currently estimate. Example of arctic permafrost (not only Antarctic) - the Pleistocene - writes Zech et al., 2011. ( High carbon sequestration in Siberian permafrost loess-paleosols during glacials.): “Recent findings show that the amount of organic carbon stored in high-latitude permafrost regions has been greatly underestimated.”
81964. Paul D at 20:39 PM on 20 June 2011
       Linking Extreme Weather and Global Warming
       A new paper to add to the SkS database? Reconstruction of false spring occurrences over the southeastern United States, 1901–2007: an increasing risk of spring freeze damage? Garrett P Marino1, Dale P Kaiser, Lianhong Gu and Daniel M Ricciuto http://iopscience.iop.org/1748-9326/6/2/024015/fulltext
81965. Hyperactive Hydrologist at 19:29 PM on 20 June 2011
       Linking Extreme Weather and Global Warming
       Couple of interesting letters in Nature from this year: Anthropogenic greenhouse gas contribution to flood risk in England and Wales in autumn 2000 Human contribution to more-intense precipitation extremes
81966. Glenn Tamblyn at 18:34 PM on 20 June 2011
       The Climate Show 14: volcanoes, black carbon and Christy crocks
       Whats your problem with Borg's? I personally feel that 7 of 9 brought a distinct gravitas to the Star Trek franchise. Ooops, sorry, I meant gravity. Well actually a sort of gravity defying uplift, a definite sort of uplifted, pointed, firmness to the exploration of unknown regions where....I might just stop there...
81967. Paul D at 17:24 PM on 20 June 2011
       Linking Extreme Weather and Global Warming
       Norman: "Why is it that looking at history of weather and climate you cannot find any examples that we are entering uncharted territory and things will get much worse." Because when you look to the past, you find individual events from history that were caused by regional inputs rather than global inputs. It's easy to pick events that are hundreds or thousands of years apart and say that they were not a result of rising greenhouse gases. It's more difficult to find events that occurred within a few years or months across the globe and attribute them to local and/or unconnected inputs.
81968. Paul D at 17:05 PM on 20 June 2011
       Linking Extreme Weather and Global Warming
       Norman: "I am "questioning" but not denying the possibility that global warming is leading to more extreme weather events." The issue isn't that extreme weather events are being observed and that they are caused by global warming. The issue is that global warming will cause extreme weather and the frequency will increase, if the science of warming is established and it is accepted that warming is taking place, then extreme weather is likely to be attributed to those changes because that is what we would expect.
81969. Paul D at 16:57 PM on 20 June 2011
       Linking Extreme Weather and Global Warming
       Norman: "When you say that US Spring weather is going to be the most extreme to date what are you defining?" It's not me that is defining it: http://www.businessweek.com/ap/financialnews/D9NSVHGO0.htm
81970. guinganbresil at 16:13 PM on 20 June 2011
       The Planetary Greenhouse Engine Revisited
       Patrick 027 - That is a good scenerio. If the atmosphere below the cloud deck is initially transparent to IR - say Argon or something like that, then the bottom of the clouds would absorb the upward radiation. Since the cloud bottom is in a saturated state, its altitude would be determined by those conditions. By adding and absorbing gas below the cloud deck you would block that radiation lower in the atmosphere. Convection in the troposphere should keep the lapse rate essentially the same. Since the cloud bottom is no longer exposed to the long wave radiation from the surface I would expect its altitude to lower a bit since it is no longer being 'burned off' by the radiation. As viewed from the space there is no change in the outgoing radiation spectrum since the cloud tops have not been affected by what is going on below. Therefore, the planetary heat balance is as it was before - no change... Granted this is a thought experiment only - Earth is quite a bit more complicated - spotty cloud deck, etc... But it does show an example of increasing GHG w/o an impact on the planetary heat balance.
81971. Tom Curtis at 14:38 PM on 20 June 2011
       Linking Extreme Weather and Global Warming
       Norman, I assume your post was deleted for being off topic. I have therefore responded here where I believe it to be on topic. If you think I have mischaracterized your point, please respond there.
81972. Tom Curtis at 14:36 PM on 20 June 2011
       There's no room for a climate of denial
       Norman commented in a post on another thread about reasons for denial. The post was deleted, presumably because it was well and truly of topic on that thread, however, I wish to respond to some points he made. I assume it is on topic here (please delete if not) and so shall respond here. The gist of Norman's comments (and working from memory, so apologies if I get it wrong) is that many people are deniers because, no matter what large scale weather event occurs, somewhere in the MSM will be a report connecting it to global warming. Based on a well known aphorism, that which explains everything, explains nothing. As I had previously indicated climate scientists do not simply attribute everything to global warming. Rather, they make such attributions when they have some causal mechanism in mind which would justify the connection. Those connections may be disputed, indeed, controversial amongst climate scientists, but those who make the attributions do so because of their understanding of the science. Unfortunately this does lead to a problem in the mainstream media. The MSM is not discriminating in its reporting, and will accept uncritically almost anything that can fill the pages. Its reporting of science, in particular, is atrocious. Consequently when some scientist with an as yet disputed mechanism steps forward attributing some weather phenomenon to global warming, the reporting will not indicate if the attribution is speculative, preliminary, or well founded. Nor will it indicate whether the mechanism is being considered by only a few researchers, or commands a consensus. All just goes into the melting pot of misinformation that we call "news". This goes to show that science by press release is a bad idea. It has never had anything to commend it except personal aggrandizement. Not that the scientists are always to blame. If major weather events are happening, reporters will ask for a comment and then shears all context and nuance from the reply. Then the sub-editor shears all context and nuance from the story in deciding the headline, and its the headline that sticks. My point is, however, that this is not a reason for denial in any person, or at least it is not a substantive reason. I once debated with a man who was convinced that global warming was wrong because he was convinced that he could remember the temperature from fifty years ago in his youth, and distinguish between those of today. It was, according to him, warmer then than now. That the thermometer readings disagreed with him (it was Australia, not the US), that Australia, let alone a small rural town in Victoria is not the globe, that we can't distinguish temperatures with the necessary sensitivity from day to day, let alone acrosss decades, and that the elderly are notorious for feeling the cold more - all where irrelevant considerations. He had his Reason, and science could go hang. Nobody of sound mind could consider that an acceptable reason to be a denier. Well the same is true of the activities of the mainstream media. They are notorious for getting things wrong, for beating up non-existent controversies, for exaggeration and for over simplification. If I were to trust the mainstream media, I would think that 30% or more of climate scientists disputed global warming. Because of these well known features of the mainstream media, anybody who bases their disagreement with climate science on media reports is on a fools errand. They may be deniers, but they certainly are not skeptical. Had they been even a smidgeon skeptical, they would have known the propensities of MSM, and not attributed to climate scientists the ridiculous hodge-podge view that they do.
81973. Daviddriscoll at 14:18 PM on 20 June 2011
       CO2 is coming from the ocean
       Could you possibly include some more info/links for the "Measurements of carbon isotopes ........ show that rising carbon dioxide is due to the burning of fossil fuels" statement please?
81974. CharlesW at 14:16 PM on 20 June 2011
       Breathing contributes to CO2 buildup
       When I was a kid in the 1970s, there were 4 billion people. Now there is 7 billion. So there should be more CO2 due to breathing now than in the 1970s, not to mention the increased livestock.
       Moderator Response: (DB) Human respiration is part of the natural carbon cycle and has no net long term impact, unlike the bolus injection of fossil fuel CO2 into the carbon cycle.
81975. Tom Curtis at 14:05 PM on 20 June 2011
       Linking Extreme Weather and Global Warming
       h/t to Norman for this post which Eric and Sphaerica may be interested in:

       "Be that as it may, rather than take a party-line on snowfall accumulation, I rather just see what the science research and basic physics tells us, and ignore the models. In general, colder periods on earth were dry, not wet, and snowfall accumulation was lower not higher. The coldest place on earth, Antarctica is also one of the most dry in terms of precipitation. 100,000+ years of ice core data shows that when the planet began to warm, accumulation increases and when it begins to cool (as in going into a a glacial period, accumulation decreases. The thing about glacial periods is not that it is snowing much more, but rather, the spring and summers are much cooler so the snow doesn’t melt, and then when the next winter comes, it snows on older snow, and guess what, you get glacial growth. That’s the way it happens. Big snows in the winter don’t necessarily mean anything other than we’ve had a warm enough atmosphere to transport and hold all that moisture. It takes a lot of energy to move all that moisture and warm atmosphere to hold it while it is being moved. You don’t get big snowfalls EVER in the middle of Antarctica– basic physics tells you that. Now, as far as “predictions” by the AGW community as to whether there will be snowier or less snowier winters– yes, there will be. But in a system like the climate, that exhibits spatio-temporal chaos, it is a crap shoot to say when and where it will be snowier or less snowier and there is not a consensus opinion among the experts about any of this, but for some reason, AGW skeptics want to paint it that way."

       (From R Gates, a little ray of sunshine in a pit of darkness)
81976. Patrick 027 at 14:04 PM on 20 June 2011
       The Planetary Greenhouse Engine Revisited
       Re guinganbresil - adding a specific point, consider that if you have a layer of clouds and a much hotter surface some distance below it, those clouds will be heated by that layer from radiation. Having gases that block some of that radiation will reduce that.
81977. scaddenp at 13:58 PM on 20 June 2011
       How would a Solar Grand Minimum affect global warming?
       "However, the changes in the solar magnetic field are much larger, and may have a more significant impact." I would have to say that sounds like a rather desperate clutching of straws (ignore the simple, coherent, physical explantions for climate change, and hope something more exotic turns up). Do have any published evidence of a link between solar magnetic field and climate?
81978. Bibliovermis at 13:56 PM on 20 June 2011
       Climate's changed before
       "Belief" pegs your intent. All of your points have already been addressed on this site, with direct references to primary source material. Healthy debate is occurring constantly. Denial and willful ignorance of the accumulated scientific knowledge is not a means of healthy debate. e.g. argument #51: Does high levels of CO2 in the past contradict the warming effect of CO2? The Ordovician glaciation was a brief excursion to coldness during an otherwise warm era, due to a coincidence of conditions. It is completely consistent with climate science. argument #96 CO2 is not the only driver of climate Theory, models and direct measurement confirm CO2 is currently the main driver of climate change.
81979. Greg House at 13:53 PM on 20 June 2011
       Of Averages and Anomalies - Part 1A. A Primer on how to measure surface temperature change
       Glenn, you have given an example, where Average of Anomalies produces a better result, than Anomaly of Averages. However, if you take other numbers, you might get quite the opposite: a better result with Anomaly of Averages. E.g. take this, please: A = 15, B = 10, C = 5, D = 20 & E = 25 Then for one day's data their individual readings are: A = 15.8, B = 10.4, C = 15, D = 20.4 & E = 25.3 Then you will get 2.4 instead of 0.52, the other numbers will remain the same and, if my calculation is correct, this time Anomaly of Averages will get your a better result. The whole thing depends on what the station C would have recorded on that missing day, if that had been possible. You actually do not know that, because there is no record for that day. Hence you do not know, which method is better, this is the problem.
81980. u4486662 at 13:42 PM on 20 June 2011
       Climate's changed before
       There is no sceptical argument that climate has changed in the past and therefore can't change because of humans. The sceptical argument points to times in the past when the earth has been much cooler and CO2 levels were much higher than they are today. It also points to the various known contributors to climate change and the complexity in which they interact. CO2 is a secondary greenhouse gas and theoretically therefore can absorb infrared light and hence heat - but of course its far more complicated than that. The net effect of cloud formation is cooling not warming and this is likely to effect projected models. CO2 has risen from 0.02% to 0.039% since the industrial revolution. The belief that the CO2 rise has led to a radiative forcing level of 3.7W/m-2 is debatable in itself. Of course you use the IPCC reference which assumes a climate sensitivity level of CO2 of 0.8K. The key word is assumption and its what most of the models are based upon, assumption. There are many other credible sceptical arguments which provide a counterpoint and healthy debate should continue. Its important to remember that sceptics are not anti-environment as some posters say but in fact I am pro-environment. Poverty in Africa is causing more damage to the environment than industrialisation and development would.
       Moderator Response: (DB) Nice Gish Gallop. Pick the point you feel the strongest about, use the Search function to locate the most appropriate thread and post just that point there; someone will get back to you very quickly.
81981. Bern at 13:29 PM on 20 June 2011
       The Climate Show 14: volcanoes, black carbon and Christy crocks
       @Badgersouth: He was just trying to show off that nice fluffy collar... :-P (As a fellow Queenslander, John, I sympathise entirely!)
81982. Eric the Red at 13:10 PM on 20 June 2011
       How would a Solar Grand Minimum affect global warming?
       I do not believe that anyone has associated the change in TSI with global warming, as reported in the previous posts. However, the changes in the solar magnetic field are much larger, and may have a more significant impact. This would be greater outcome of a grand solar minimum.
81983. Eric the Red at 13:04 PM on 20 June 2011
       Linking Extreme Weather and Global Warming
       Sphaerica, You seem to be backpedalling rather rapidly. I have not been able to determine if you are making any correlation between temperature and snowfall at all. You claim that temperatures have not risen long enough to determine a correlation, but do not want to wait until they do to determine one either. Lastly, my references to European snowfall and North American snowfall, while regional in each case, amount to most of the global mid-latitude snowfall. Yet, your refer to this as regional, then make the claim that your statement about colder winters was a specific case in North America. You seem to want to extend yout theories across the board without proof, yet deny someone's else even though all the evidence presented supports it. (-Snip-)
       Moderator Response: (DB) Someone's profession has no bearing on their ability to formulate a cogent and coherent comment on this forum.
81984. Tom Curtis at 12:17 PM on 20 June 2011
       Linking Extreme Weather and Global Warming
       Eric (skeptic) @83, with respect, "...the recent extreme El Ninos in 82-83 and 97-98 were not due to AGW warming kicking in earnestly after the 70's warming" cannot be the null hypothesis in this case. This is for two reasons. First, the simple denial of a hypothesis cannot be the null hypothesis for any statistical test. A test of statistical significance tests against the probability that the test statistic being the result of the null hypothesis, and to do that you must have a defined value for the probability that an event will occur given that the null hypothesis is true. To determine the probability of the denial of a given hypothesis, however, you must know the probabilities of the events under all logically possible contrary hypotheses. As the number of possible contrary hypothesis is infinite, you cannot even enumerate them, let alone sum their conjoint probability. Hence the denial of a hypothesis can never be a null hypothesis because you can never define the probability of the event given that the hypothesis is false. Second, the null hypothesis must always be a purely statistical hypothesis. This is because you cannot observe causation. You can only observe correlations. If you use a causal null hypothesis, you could have a situation of perfect correlation over tens of thousands complexly varying observations and still not find statistical significance because there may be some as yet unknown alternative cause. Taking this into mind, a sensible null hypothesis is that:

       The probability of a high intensity ENSO event is independent of mean tropical pacific heat content.

       . Using that null hypothesis, the probability of the observations of extreme ENSO events observed post 1940 is around 15%. It is highly likely that the probability of the total set of observations in Gergis and Fowler given that null hypothesis is less than 5%, and hence that there is a statistically significant correlation between mean tropical pacific heat content and the intensity of ENSO events. Of course, "global warming" causally predicts increased tropical ocean heat content, so the test is not arbitrary with respect to global warming - but what is tested statistically is statistical, not causal correlation. Finally, the feature of Moy et al that is challenged by the other three studies is the correlation between their chosen proxy and ENSO states. If the other three studies are correctly reconstructing ENSO variability, then the ENSO reconstruction of Moy et al over the last thousand years has no skill. Therefore we have no reason to trust it for the seven thousand years before that. But the other three studies either us multiple and geographically diverse proxies (the entire US for Li et al, up to 14 proxies with global coverage and with ten of those being in the Pacific or Pacific rim for Gergis and Fowler), or use proxies directly related to the ENSO by geographical location rather than climactic correlation (Doran et al). Consequently it would be very dubious to accept Moy et al's reconstruction as being more reliable than any of the other three, and certainly not more reliable than the conjoint signal of the other three. It is possible that closer examination will show the discrepancy between Moi et al and the other three to be more apparent than real, but until that closer examination is made, relying on Moy et al to contradict the other three is believing against the evidence rather than with it.
81985. Bob Lacatena at 11:57 AM on 20 June 2011
       Linking Extreme Weather and Global Warming
       82, Eric the Red, Sorry, Eric, I didn't realize you'd asked a question. But my answer would be that the search for an increase or decrease in current observations is irrelevant, because temperatures haven't been elevated long enough, and the increase has not yet been great enough, to say what the effects will be for any particular region merely through observation. What is needed, instead, is an understanding of what mechanisms will be affected, and what the implications are going to be. But then, that in a nutshell is most of climate science. Figure out what's gong to happen, by fitting all of the pieces together. I'm afraid I don't agree with your method, which appears to be to basically to wait until something unequivocal actually does happen. But, with that said, the trend line for northern hemisphere winter precipitation is slightly positive (and if you look at it from 1990 on, it seems more strongly positive), and spring is strongly negative. Rutgers Northern Hemisphere Winter Snow Extent Rutgers Northern Hemisphere Spring Snow Extent On your comment about colder winters... you're incorrectly comparing a specific, local phenomenon with a global mean prediction. Yes, overall, on average, winters will get warmer. Winter temperatures in total will be warmer. The reference I made was to a specific case where North American winters will still be shorter, but may paradoxically be colder because the much colder Arctic air (which is warmer than normal, but still very cold by North American standards) may frequently get pushed south over the continent. This is been my main point all along... that the devil is in the details. You can never, ever take a very simplistic approach (more humidity must mean more precipitation, or warmer winters must mean less snow) and apply it across the board. You simply can't.
81986. Eric (skeptic) at 11:15 AM on 20 June 2011
       Linking Extreme Weather and Global Warming
       Tom thanks for the elucidation, you are right about the single proxy, and Moy et al talk about the potential problems with it, but mostly for 7k or more years ago. Their long term (7k) trend presents a powerful argument for a natural increase in ENSO event although not necessarily extreme events. That is notwithstanding the lower frequency in the last 1200 years. The other statistics in Gergis and Fowler are interesting but IMO are not direct evidence against the null hypothesis which is (to restate a bit) that the recent extreme El Ninos in 82-83 and 97-98 were not due to AGW warming kicking in earnestly after the 70's. I would argue that the reduced ENSO extremes in the LIA have potential confounding factors (solar -> weather patterns -> winds and/or clouds) that are not relevant to the post 70's warming. An alternative to the hypothesis testing from empirical data above is to describe a physical link from the AGW to the ENSO extremes. ENSO is the response of an oscillatory system from effects that are secondary to warming, e.g. winds. But it is conceivable that the warming changes the system's response such that the peak of the oscillation is increased over normal.
81987. Tom Curtis at 11:10 AM on 20 June 2011
       How would a Solar Grand Minimum affect global warming?
       Ken Lambert @63, "radiative forcing" is defined as "... the change in net (down minus up) irradiance (solar plus longwave; in W m–2) at the tropopause after allowing for stratospheric temperatures to readjust to radiative equilibrium, but with surface and tropospheric temperatures and state held fixed at the unperturbed values" (Quoted from IPCC AR4, my emphasis) The current uncertainty in measured change in TSI is 0.014 W/m^2 per annum according to the SORCE homepage, or less than 1/300th of the figure you use. For comparison purposes, that is a relative accuracy of 0.001%/yr (10 ppm). Over the entire satellite period, the relative uncertainty of the PMOD index is estimated as follows:

       "An estimate of the uncertainty of the long-term behaviour of the composite TSI can be deduced from the uncertainty of the slope relative to ERBE. For the PMOD composite the slope over the whole period amount s to 1.1 +/- 2.1 ppm/a. Although this standard deviation is partly determined by the sampling of ERBE we may estimate the uncertainty of a possible trend to be <3 ppm/a for periods longer than 10 to 15 years. This implies a possible change of 50 to 80 ppm over the 23 years of the observations. If we add the uncertainties related to the tracing of ACRIM-II to I and of the HF correction (60 ppm) we get a total uncertainty of 92 ppm. The observed change of the PMOD composite as difference between two successive minima amounts to -10 ppm which is not significantly different from zero at the 3-sigma level."

81988. KR at 10:58 AM on 20 June 2011
       How would a Solar Grand Minimum affect global warming?
       Ken Lambert - To be more exact, the uncertainty on TSI changes are to extremely small. Changes in the data record of isolation are tiny compared the anthropogenic changes, as you are well aware. To be entirely clear, Ken, its not the sun, which has been fully and repeatedly demonstrated over and over.
81989. scaddenp at 10:54 AM on 20 June 2011
       CO2 Currently Rising Faster Than The PETM Extinction Event
       The paper which includes discussion on methane from sedimentary basins is Kroeger, di Primio and Horsfield 2011. The reservoir dwarfs other carbon sources.
81990. Eric the Red at 10:47 AM on 20 June 2011
       Linking Extreme Weather and Global Warming
       Sphaerica, You avoided my question. Do you have any data showing an increase in snowfall with rising temperatures. Also, that is the first that I have ever read that glocal warm will cause colder winters. Most have winter temperatures rising the most.
81991. Tom Curtis at 10:43 AM on 20 June 2011
       Linking Extreme Weather and Global Warming
       Norman @69, I quite agree with you that mere correlation is not that strong as evidence. In fact, I alluded to exactly that point when I wrote:

       "... it is likely (>66%) that the correlation between increased tropical SST and increased ENSO activity and intensity is not coincidental. In fact, where it not for the fact that we clearly do not fully understand the mechanisms involved, I would say it is very likely (>90%)."

       However, it is not true that climate scientists have merely come up with a correlation. The ENSO is a consequence of the walker circulation, a atmospheric circulation that creates an east-west wind at the surface parallel to the equator. That circulation is in turn cause by the temperature gradient between the warm shallow water in the western tropical pacific and the colder water in the eastern tropical pacific which is cooled by the Humboldt current. The walker circulation carries the cold water from the east across the surface of the central pacific, thus cooling the central pacific. If the walker circulation is particularly strong you will get a La Nina, if particularly weak you get an El Nino. The oscillation is introduce because once the cold water is carried east, it both reduces the outgoing surface radiation and evaporation from the surface, thus reducing cooling; and exposed a greater volume of cool water to the sun, thus enhancing warming. The consequence is that the cool water carried across the surface is warmed, weakening the walker circulation. In these circumstances, prima facie, warmer tropical temperatures will result in the cold tongue of water from ENSO warming more rapidly as it mixes in, thus increasing the rate at which the ENSO switches from La Nina to El Nino conditions. Enhanced tropical warming will also increase the temperature gradient between eastern and western tropical pacific, increasing the rapidity of a switch from El Nino to La Nina. The increased rapidity of switching is itself likely to enhance the intensity of some events in what is essentially a forced oscillator. So, this is not a case of an inference from pure correlation, it is an example of an intuitive mechanism which cannot yet be shown to be supported by theory due to complicating factors, along with a clear correlation predicted by the intuitive mechanism. Having shown your objection to be ill founded, I also reject in the most strenuous terms your insinuation that

       "This [supposed] tactic [of using correlation without mechanism] is creating the huge denier syndrome that so many on this site complain about. It is not making people concerned and want to take action, it is generating the opposite effect."

       First, I object because it is not a note worthy feature of climate science that simple correlation without some mechanism is used to "prove" anything. Even such ill understood phenomena as blocking patterns are not simply attributed to global warming analysed to determine if there are causal mechanisms involved (note the date on the press story - it is before the Russian heatwave of 2010). Because of the nature of the science, some of the mechanisms are heavily disputed within the scientific community, but those who dispute the mechanisms also dispute the attribution of (changes in frequency or intensity of) particular types of events to global warming. Second, I object because reliance on pure correlation is a note worthy tactic of deniers. And people who are so ready to use such a tactic can hardly have been put of by the supposed use of that tactic by others. That is particularly the case in that, as noted, the tactic is often attributed to, but not in fact significantly used by climate scientists.
81992. Albatross at 09:54 AM on 20 June 2011
       Linking Extreme Weather and Global Warming
       Norman and Camburn, I'm trying to enjoy Father's day, but your posts are detracting from that ;) I'll respond tomorrow.
81993. Ken Lambert at 09:53 AM on 20 June 2011
       How would a Solar Grand Minimum affect global warming?
       KR #62 "It's interesting work - but the uncertainties on TSI and other solar forcings are well below the knowns on anthropogenic forcings." The uncretainties on the 'absolute value' of the TSI are quite large if you look at the SORCE TIMS value for TSI. They measure around 1361.5W/sq.m and the earlier satellites maesure around 1366W/sq.m - a difference of 4.5W/sq.m. Last time I checked the SORCE website - since 2005 the 4.5W/sq.m difference has remained 'unresolved' amongst the scientific community studying TSI. If the correct value is in fact 4.5W/sq.m less than the accepted value - multiplying this difference by 0.7 and dividing by 4 will give the incoming solar radiation difference which is about -0.8W/sq.m. This compares with the old energy imbalance of +0.9W/sq.m and Hansen's new estimate of +0.59W/sq.m.
81994. Norman at 09:51 AM on 20 June 2011
       Linking Extreme Weather and Global Warming
       DB The Greenland temps was only a side argument for Paul D. My major question on this thread is to establish concrete links for what seems correlated weather data showing rising extremes. But I linked to Crux of the Core part 1 and looked at the Holocene temp graph. For 4000 years the temperature was warmer than it is today. And Greenland's temp is significant for the "melting away of its ice" concept. Greenland was 3 C warmer than today. I am reading that significant ice has been lost since 1979. If a 30 year period of warming can cause such a devestation to the Greenland ice sheet how could it withstand a much higher temp for much longer periods...there should be no Crux of the Core as the glacier should not have existed during those hot phases. So during that 4000 year warm period were the floods more devastating? More tornadoes, droughts, heat waves? How did man survive the weather extremes? Why didn't this 4000 year warm cycle melt the permafrost and release all the stored methane gas locked in methane hydrates?
       Response:

       [DB] You may want to study GISP more deeply.  IIRC, the chart shows no data more current than 1895 or so.  Thus the lack of representation of the modern warming era.

81995. scaddenp at 09:49 AM on 20 June 2011
       Linking Extreme Weather and Global Warming
       Norman, the robust prediction from climate theory on weather parameters is given in the article above (transpiration rate, more water vapour, higher SST). Do you doubt these parameter changes> Going from changes in these how this plays out on a regional weather is far more uncertain science. But do you seriously expect that you could change those fundamental parameters without effecting weather?
81996. Tom Curtis at 09:47 AM on 20 June 2011
       Linking Extreme Weather and Global Warming
       Eric @66, Gergis and Fowler state:

       "From Table 9, a total of 92 (82) El Niño (La Niña) events were reconstructed since A.D. 1525. Of these, 37 very-strong to extreme El Niño were observed. Nine El Niño events were classified as extreme, including five well-known events of the 20th century (2002, 1982–1983, 1941–1942, 1926, 1905). The 18th century contained a further three events (1737, 1723, 1718) while only one extreme El Niño event of A.D. 1650 was recorded during the 16th and 17th centuries. The 20th century represents the peak of El Niño activity, when twelve events were classed as either very strong or extreme. A total of 46 very strong to extreme La Niña events were reconstructed, twelve of these classified as extreme. Four extreme La Niña events (1998, 1974, 1953, 1950) were reconstructed during the 20th century. The pre-instrumental period indicates relatively more La Niña activity with 6 (24) extreme (very strong) events compared to 4 (18) extreme (very strong) events from the El Niño reconstruction. Considerable La Niña activity is indicated during the 16th tomid 17th centuries when five extreme events are reconstructed. A trend towards increased La Niña activity over the 20th century is also evident from Table 9."

       Thus over the entire 478 year period (1525-2002)of the reconstruction, the relative frequency of extreme events ENSO events is 0.044 over the entire period. Of these, seven occurred post 1939, giving a frequency for that period of 7/63. Given a relative probability of 0.044, the probability of achieving seven positive results in 63 trials is approximately 0.0142, which you are correct does not achieve the standard of statistical significance. It is also just a small part of the statistically relevant information from this study. Once you factor in the increased frequency of very strong events over the instrumental period, the increased frequency in the relatively warm 1991-1939 period, and the reduced frequency of very strong and extreme during the peak of the LIA, and particularly during the Maunder Minimum, I think your claim that the results are not statistically significant are very dubious. What is more, Doran et al (as quoted in 52 above do explicitly find that the change in frequency of ENSO events is statistically significant. With regard to Moy et al, I note that their conclusion of reduced frequency of El Nino events over the last 1200 years contradicts Gergis and Fowler, Doran et al, and Li et al above, who all find an increased frequency of ENSO events over the last thousand (Doran et al, Li et al) of 500 years (Gergis and Fowler). In view of the fact that Moy et al use a single proxy, their conclusions have to be called into question given that they contradict more recent multi-proxy studies (Li et al, and especially Gergis and Fowler). Is suspect more weight should also be given to Doran et al, even they also only use a single proxy, in that their proxy is a direct proxy of sea surface temperatures in the Central Pacific, ie, the location of ENSO events.
81997. Norman at 09:02 AM on 20 June 2011
       Linking Extreme Weather and Global Warming
       Paul D. Look at the Greenland temp graph link from the previous post. If you look at 8100 years ago to 8000 years ago you see a drastic temperature rise of 3 C in 100 years. I don't think our last 100 years is even close to this. Anyone out there, for looking at temperature extremes and drastic changes, can anyone find a link as to why Greenland's temps are so unstable?
       Response:

       [DB] There are many issues with the way disinformationists use GISP records.  See here and here for two of many posts addressing this.  If you're implying regionally variability in the past trumps current warming known to be global, then your understanding of the science is lacking.  The GISP data do not cover the current warming era.

81998. Norman at 08:55 AM on 20 June 2011
       Linking Extreme Weather and Global Warming
       Paul D @66 "Camburn "I have not read reliable data from any source that we are experiencing anything that is abnormal." A warming climate is abnormal and no sensible person is denying that the climate is warming. Glacial melt, changing seasons and numerous other changes are a very clear indicator." Paul D what happened to the Greenland ice sheet 3200 years ago. Greenland was much warmer than as compared with now...Almost 3 C warmer than today! In fact it was warmer than today for about 3000 years. If our current warming phase is so abnormal and dangerous how did all that ice last through the heat for 3000 years? Greenland temps the last 10000 years. Why is it that looking at history of weather and climate you cannot find any examples that we are entering uncharted territory and things will get much worse. I guess it is because of that nasty weather manipulating and earthquake causing HAARP station in Alaska.
81999. Norman at 08:32 AM on 20 June 2011
       Linking Extreme Weather and Global Warming
       Paul D, History of Texas droughts. I am seriously questioning the conclusion that extreme weather events are on the increase. While I am limited in time to research the globe I choose one place that is in the news and look at the historical information I can find to see if the news items are taken with a historical view in mind. I am "questioning" but not denying the possibility that global warming is leading to more extreme weather events. If linking mechanisms to can be found for given correlations than the credibilty of these claims improves. Predictability would be nice.
82000. Norman at 08:25 AM on 20 June 2011
       Linking Extreme Weather and Global Warming
       Paul D @71 When you say that US Spring weather is going to be the most extreme to date what are you defining? Is it extreme tornado events, floods, droughts, snow (still snowing in some mountain locations). What other springs are you comparing it to?

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