Extremely hot

IPCC (2001) graph illustrating how a shift and/or widening of a probability distribution of temperatures affects the probability of extremes.

For illustration, let’s take the most simple case of a normal distribution that is shifted towards the warm end by a given amount – say one standard deviation. Then, a moderately extreme temperature that is 2 standard deviations above the mean becomes 4.5 times more likely (see graph below). But a seriously extreme temperature, that is 5 standard deviations above the mean, becomes 90 times more likely! Thus: the same amount of global warming boosts the probability of really extreme events, like the recent US heat wave, far more than it boosts more moderate events. This is exactly the opposite of the claim that “the greater the extreme, the less global warming has to do with it.” The same is also true if the probability distribution is not shifted but widened by a constant factor. This is easy to show analytically for our math-minded readers.

Graph illustrating how the ratio of the probability of extremes (warmed climate divided by unchanged climate – this increased likelihood factor is shown as a dashed line, scale on right) depends on the value of the extreme.

So in summary: even in the most simple, linear case of a shift in the normal distribution, the probability for “outlandish” heat records increases greatly due to global warming. But the more outlandish a record is, the more would we suspect that non-linear feedbacks are at play – which could increase their likelihood even more.

Update 29 March: New Scientist magazine cites this RC post in an article about the “summer in March”.


Our Perspective article on the unprecedented extremes of the last decade was just published by Nature Climate Change: Coumou & Rahmstorf (2012) A decade of weather extremes


Otto et al., Reconciling two approaches to attribution of the 2010 Russian heat wave, Geophysical Research Letters 2012, VOL. 39, L04702, doi:10.1029/2011GL050422

Schär, C. et al. The role of increasing temperature variability in European summer heat waves. Nature 427, 332–336 (2004).

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210 comments on this post.
  1. Salamano:

    I have a question.

    If your specific methodology in regards to the “Moscow Warming Hole” research was applied directly to the extreme cold event in Europe that has been discussed continuously this winter (ie, http://www.bbc.co.uk/programmes/b01f893x )

    …How would the loaded climate dice exercise conducted then show the likelihood of this event occurring?

    [Response:Our approach in that paper assumes a probability distribution that shifts towards warmer temperatures, but is otherwise unchanged – just like the simple example given in the second graph above. Something like an extreme cold event related to sea ice loss obviously can not described in this way – it is a great example of a highly non-linear mechanism. stefan]

  2. Kasuha:

    I believe there’s no dispute the increase in mean has occurred (if not later then sure between 1950 and 2000), all main temperature records agree on that. But I know record lows are still being reported – they just don’t get as much publicity as highs. For example this year’s Europe/Asia cold wave in February was a particularly nasty one, many stations recorded more than one record low over the ~month it lasted. I happen to live in that area so I had that experience directly delivered to me.
    Another thing is I don’t know how record low statistics compare with record highs. I know here are record highs recorded, there are record lows recorded but I don’t know how many and how extreme. Plus, as there was that above mentioned mean shift, one would expect the record low statistic to be affected by it regardless on current trend.
    Could I ask for your guess/results on how much the variance has changed and how big the variance is compared to the recorded mean change?

    [Response:I’m looking after my sick little daughter today so won’t be able to be involved further in the discussion. But I’m sure some of our readers can answer your questions. -stefan]

  3. Lab Lemming:

    Re #2:
    Some of those numbers are here:
    Ask Dan (that blogger) if his sources are US or worldwide.

  4. Salamano:


    I believe ‘everyone’ does agree that record lows exist and will continue to exist, but just in fewer numbers. I think the current data has the establishment of record highs far outpacing record lows, which would be expected in a warming world.

    I asked Dr. Mann about the European cold spell as well at a different venue, and his initial thinking was that the event was not “global warming induced” (instead brought on by natural variability), but then left open the idea that it would be, because of what Rahmstorf was saying regarding the loss of sea ice. However, it led me to wonder what goes into the selection process to identify ‘event candidates’ for the application of the methodology that gets published.

    Also, considering the anticipated greater loss of sea ice in future years, I suspect we’ll have to have more of the extreme cold events of the kind that affected Europe. Perhaps this is a non-linear ‘feedback’ that non-zero-ly affects the forward progression of global warmth?

    I was analysing those three graphs put out by the IPCC and trying to resolve in my head a scenario that would accomodate both the Moscow warming event and the record Europe cold of this year. It would seem that graph #2 is best, but then that would imply no net warm progression of temperature. If one of the ‘warming’ graphs are chosen, than the “climate dice” idea becomes unworkable for any extreme event involving cold. I would hope that such methodology doesn’t just become only applicable for warming events– it then becomes technically unfalsifiable. Perhaps there will be a 4th graph developed that demonstrates a warmer progression while also maintaining a higher variance that makes both cold events and warm events more likely. At this point, perhaps the thinking is “less cold events, but more ‘extreme’ cold events”(?) Makes for an interesting distribution.

    …I wonder if we all are home with sick daughters today (mine just finished with “spring break” and today was to be their first day back, go figure).

  5. J Bowers:

    Re. 2 Kasusha

    For the US: Heat Wave Sends Temps Soaring into Uncharted Territory

    The volume of records being set during this long-duration heat wave is staggering. On March 18 alone there were 1,597 warm temperature records set or tied in the U.S., compared to just 58 cold temperature records. For the year-to-date, there have been 14,737 warm temperature records set or tied, compared to 1,296 cold records — a ratio of about 11-to-1.

  6. Pekka Kostamo:

    Jeff Masters has discussed recently the mechanisms on his blog.

    In a warming world hot and cold waves are both generated by changes in the polar jet stream. Slower rotation of the meandering jet ring and and its bigger fluctuations give more time for the cold and hot flows to do their work. In general, the “prevailing weather types” are becoming slower changing, which incidentally makes the weather forecaster’s work a little bit easier. “Tomorrow the same weather as today” holds good a bit more. Periods of fair weather become longer and the successions of depressions bringing rain likewise.

    Another aspect of warming impact is that the timing and geographic patterns of what is called “weather” changes completely, as explained also by Masters. Probabilities shift a little bit as described here, but the everyday readings have no relation between the “warmed up” and “unwarmed” weather situation.

    On this single day, the thermometer at my window reads +1,0 degC. In an “unwarmed” world the reading could be anything between -25 degC and +10 degC, that being the observed previous range for this particular day of the year.

    This applies also the the low probabily tails. To the consternation of most, the “Katrina” would almost certainly not have happened on that particular day in an “unwarmed” world. Nor necessarily on any other day either, as it was a very low probablity event, the like of which the Gulf coast has seen only 3 in a hundred years.

    Yet, it is not right to say the particular storm was caused by climate warming. It was just a random fluctuation generated within a given climate framework and could have occurred with the same very low probability also in an unwarmed world, on that day or on any other day of the active seasons.

  7. wili:

    JBowers, you beat me to it. And that 11-1 ratio for heat records over cold so far this year comes after years of steady increase–2-1 over the last couple decades, 3 to 1 in the summer of 2010, and 8 to 1 last year.


    But these are still just US ratios. I, too, would like to know what the ratios are and have been on the global level.

    In general, it strikes me that, useful as these abstract probabilistic models can be, they can’t really capture the complexity of a the system and the wide range of possibilities, especially over the relatively short term.

    Just for one example, if it turns out that, between melt of sea ice and Greenland ice, the North Atlantic Current slows or stops, we would expect to see fairly dramatically colder weather in Europe for a while, even thought this condition could be directly linked to results produced by GW (though in the long term, the warming would, presumably eventually overtake the cooling from change in ocean currents).

    The main point is that the disruption provided by greater overall warming of the global atmosphere is leading to all sorts of extremes, mostly, but not all necessarily, on the hot side. Gaussian distribution may not be fully adequate to describe the complexity of the system.

  8. James Staples:

    Yes, and then, whenever it ISN’T ‘Hot enough to convince them that Global Warming is “real”‘, that, too, it “proof” that it’s all BS, Blargl, Yargl, Blaaarh!!!
    Don’t you wish Everyone had taken Statistics? (Note: I didn’t, but I ‘get it’, any-old-way); that they understood ‘The Law of Averages’?
    Probably out buying Lotto Tickets, in the full assurance that ‘After they’d lost X number of times’ then the odds MUST have Improved…….
    Keep Up the Good Work!!!

  9. LarryL:

    Durng the recent, and on-going, heat wave impacting most of the central and northern US and southern Canada, temperatures in many areas were well over 30 degrees above average.
    Is that same type of heat anomaly possible with summer time temperatures? Or does the outside range of the anomaly get smaller as the average temperatues get warmer?

    Here in St. Louis, the average Aug temp is 88F. What types of temperatures could we hit if the March heat wave occured in August?

    [Response:Good and extremely important questions, and I do mean extremely. You apply the same magnitude of relative heat anomaly (i.e. relative to the seasonal mean) at the hottest time of the year and you are looking at serious trouble, highly dependent on precipitation and general soil moisture levels, but potentially extremely serious in effects. This is why the example in the post about the amplifying effects of previous, cumulative heating due to a gradual shift in the T distribution, on a subsequent heat wave event, is a very good and important one–Jim]

  10. Chris Dudley:

    This is a good point and it counters my recent criticism of Jeff Masters’ statement to some extent:

    “Of course, using 30 years of data to estimate extreme events with a return period of centuries is a sketchy proposition. However, keep in mind that had we used a century-long climatology instead of using the past 30 years, yesterday’s warmth would have been classified as much more extreme, since the climate has warmed considerably in the past 30 years. It is highly unlikely the warmth of the current “Summer in March” heat wave could have occurred unless the climate was warming.” –Masters


    Probability-wise shifting the mean back O.3 C or so, to match the situation in the Midwest, you might go from 4.5 sigma to 4.6 sigma making the extreme 1.6 times less likely for a 100 year timescale climate estimate than for a 30 year timescale climate estimate.

    But, I think that problems arising from including the trend within the variance estimate still make the statement problematic.

    And, the warming is global and may not be local, or at least not perceptibly so. There are regions of cooling in the 100 year gistemp trend map for March in northern Canada and in central Australia but is seems doubtful that these local cooling trends make a warming attributable heat wave less likely in those areas. Have those regions had less cooling than they would have without global warming? Or, rather, would a different realization of warming have shifted the cooling spots to different places? April looks different from March in this measure.

    Surly, also, most scientists realize that scrabbling around at the 0.1 sigma level is methodologically very dangerous ground. Telling the difference between 4.5 and 4.6 sigma implies a precision in the determination of sigma that is rarely justified given the influences of non-Gaussian effects that may interfere. The point made here by Stefan and Dim seems valid but faces difficulties in its practical application.

    As a practical matter, I think that Hansen’s recent approach of looking at the fraction of the Earth’s surface which is experiencing extreme warmth does a good job of making a global measure to compare with global warming. http://www.columbia.edu/~jeh1/mailings/2012/20120105_PerceptionsAndDice.pdf

    This avoids the problem that any particular 4.5 sigma event might be expected simply because we expect a 4.5 sigma event somewhere some time. I think what is presented here by Stefan and Dim could be very profitably applied to a discussion of that work.

  11. jgnfld:

    I think one problem with the “it’s really hot therefore global warming” argument is that people do not see it in the (quite correct) terms you are presenting it. Many, I think, tend to think the whole globe has been experiencing a heat wave this March–something that is patently not the case–and then feel cheated when the aggregated number come out so minimal in any short period as they must over any sufficiently short period given the first law.

    For example, I doubt that worldwide, the monthly GISTemp, HadCRUT or other series will be wildly anomalous as the great heat in the US/Central Canada is well balanced by cool areas elsewhere–Newfoundland where I live being one of them :-( .

    Basically, I think that the inability of untrained people to see that the statistical argument you’re making is correct is a real problem. I’m not sure I have any ideas for countering this problem, but it sure makes explanation hard.

  12. wayne davidson:

    Again nice work which demonstrates and compresses a 4 dimensional event into a 2 dimensional graph.
    It explains the possibility of such an occurrence, but I rather have pictures and maps, it also may be a 5 dimensional phenomena including chemistry (CO2 for instance). The greatest cause of this heat wave is the shrinkage of winter around the North Pole, which took decades before happening this way, one side of the world is bound to be hotter while the other normal, its been going this way for more than a decade, and its getting hotter during winters; no ice in High Arctic Mid-November (1998), bees in N.Y. January, tulips in the UK February, summer heat in North American March, the spinning of the heat zone during winter will continue and expand . Again one must look at mirror causations, the biggest one is the shrinking Cryosphere, This heat wave is the reflection of sea ice volume disappearance.

  13. Susan Anderson:

    Wonderful, I will look forward to reading some real science on this issue and studying the article in depth as far as I am able to.

    GSW, here’s some fodder for your question to the scientists that I unfairly fielded with my amateur comments (elsewhere).

    nice taste (niciest gutta captcha!)

  14. Ray Ladbury:

    It seems to me that the basic problem with this type of analysis is that the question one is trying to answer is whether the distribution is changing by looking at the extremes of the distribution. This is bound to be problematic since the extremes of the distribution are always poorly known do to the rarity of events from this poriton of the pdf.

    The one thing you can probably say with relative certainty is that by the time you get out to 5 sigma, the pdf probably ain’t normal.

    [Response:But you’re not restricted to looking at the extremes Ray. You can look at the rest of the distribution as well. EDIT: Meaning, to get an idea of whether the overall distribution is changing, and how–Jim]

  15. Edward Greisch:

    ”Since this heat wave broke the previous record by 5 °C, global warming can’t have much to do with it since that has been only 1 °C over the 20th century” LOL [laughing out loud] Any excuse, no matter how contorted the logic.

    And I sure do wish statistics was a required course in K-12 and for all majors in college. Most people who know nothing about it think they know all about it.

  16. Mike Roddy:

    Chris Dudley, a Dot Earth commenter, linked this RC article, and pointed out that Andy Revkin has long denied links between extreme weather and global warming. Andy responded by linking to an article behind a paywall written by a “leading climate scientist” I have never heard of, named John Wallace, I believe. Andy implied in his comment that RC, a careful and rigorous group, is in some sort of alarmist camp, and that his guy is the one sticking to the evidence.

    I know that RC people are serious, and don’t want to get dragged into yet another “debate” by people like Revkin and the Breakthrough Institute, who love to wag their fingers at anyone who proposes a link between extreme weather events and global warming. The science here is rather obvious if one has a mathematical mind, which BTI and Andy do not. I don’t know about the study he quoted, but can assume it’s more soft denier material.

    Not sure if there’s any remedy for this, but wanted RC readers to know what’s going on. Quality climate science is now being routinely targeted by news organizations and previously credible reporters and politicians. The time is long past for scientists and their professional organizations to go beyond general statements, and begin to aggressively counter the flood of the discredited science that continues to worm its way into our media outlets. Nobod else is going to do it for you, since almost all MSM reporters are either bought or terrified.

  17. GSW:


    Thanks for remembering me!

    I think on the other thread the question was couched in a slightly different manner to how it has been outlined here.

    Specificaly, we were talking about a regional warming event in the context of an otherwise unremarkable month for “Global” temperatures. So should we look for, and attribute, “significance” in short term, regional, anomalously Hot and Cold events? is it correct to do so?

    Posing the problem in a contrary manner; if the yearly Global Temperature anomaly was above average, but the year was marked by a number of very anomalous “Cold events” in say Russia, what weight would we attribute to these events relative to the Global signal?

    I’d argue that short term regional events are not a good metric either way. They are more a consequence of an unusual weather pattern than a background “Global” trend.

  18. Steven Franzen:

    @2, Kasuha,

    For Europe a nice and accessible data source is the ECA&D (European Climate Assessment & Dataset) project. For example, one can easily plot individual time series as narrow as a single station or compiled maps showing anomalies/trends for the whole continent.

    As measures for extreme values, the indices TX90p (incidence of daily max. temperatures above 90th percentile) and TN10p (min. night temps below 10th percentile) could be informative. Even though 10th/90th percentile conditions are not particularly extreme deviations, a discrepancy in the trends of both numbers is quite apparent, with daytime maxima increasing quicker than nighttime minima are decreasing.

    That said, not only the eastern USA, but also the northwestern Europe has been shielded by a surprisingly stable area of high pressure for the past week or so. In my area (Netherlands) it has produced daytime maxima of 18-20 degrees (Celsius), very unusual compared to the 1981-2010 average of 10.6. The current month is certainly going to end up in the top 5 warmest March months on record, possibly in the top 3.

  19. Brian Brademeyer:

    I have recently been looking at weather effects on bark beetles with a century of weather data (1910-2009) for the Black Hills, and the standard deviation of average monthly temperature does indeed show an annual cycle, with minimum in August (1.521 F) and maximum in January (3.514 F).

    March is nearly double the August standard deviation (2.866 F), so a “similar” August heat wave would involve a smaller absolute temperature deviation (about half) than the current March heat wave.

    [Response:Your argument misses the point in three different and important ways, not even considering whether or not the Black Hills data have any general applicability elsewhere, which they may or may not: (1) It ignores the point made in the post about the potential effect of previous, seasonal warming on the magnitude of an extreme event in mid summer to early fall, due to things like (especially) a depletion in soil moisture and consequent accumulation of degree days, (2) it ignores that biological sensitivity is far FAR greater during the warm season than the cold season for a whole number of crucial variables ranging from respiration and photosynthesis to transpiration rates, and (3) it ignores the potential for derivative effects, particularly fire and smoke, in radically increasing the local temperature effects of the heat wave. So there is no comparison whatsoever.–Jim]

  20. Paul S:

    GSW – ‘So should we look for, and attribute, “significance” in short term, regional, anomalously Hot and Cold events? is it correct to do so?’

    I think the point is to determine how often extremes might happen, statistically speaking, in order to inform planning decisions. Think of the 100-year flood concept as an analogue.

    ‘They are more a consequence of an unusual weather pattern than a background “Global” trend.’

    I think you should read Stefan and Dim’s post. Global warming does not manifest only as a linear trend on a graph, averaging at the global level. The changes brought about through human activity will influence and are influencing regional weather patterns. The question is ‘in what way?’ Some extremes may become more likely, some less likely.

  21. Ray Ladbury:

    Yes, certainly, you have to look at the events from the central portion of the pdf. However, they don’t provide much constraint on the extremes. How do you know that you haven’t affected the skew, for example, as well as the mean and standard deviation? How do you know your distribution is still unimodal, or indeed was unimodal in the first place?

    Attribution is always a fraught proposition when it comes to extreme value stats.

    [Response:I agree Ray, that the central portion provides little information, if any, on the probabilities represented by the tail ends. As for the distribution shape, it’s always going to be unimodal, that’s for sure. And the changes in the higher moments was exactly my point in saying you need to look at the rest of the distribution–that will indicate whether the skew, kurtosis etc are changing–or rather the other way around: changes in those computed moments will tell you if the shape of the distribution is changing, which is what you want to know.–Jim]

  22. Tokodave:

    I can’t help but be reminded of a post over at Tamino’s Open Mind Site that concluded with:I’ll continue to do what I can, come hell or high water. Expect both.

  23. Ray Ladbury:

    Sorry if I am being a bore, but skew and kurtosis require quite large datasets to estimate–and the thicker the tails the more data they need.

    And just to play devil’s advocate, given the importance of the jet stream, would if always be unimodal?

    [Response:Not being a bore Ray. But if I follow your line of reasoning, how are you ever going to detect any type of climatic change of any magnitude at all? Your reasoning seems to preclude it, because it doesn’t allow you to estimate the shape of the distribution, either before or after the change. And I can’t imagine any situation in which the distribution of a T variable is other than unimodal–other than perhaps a uniform distribution, which itself would be highly unusual.–Jim]

  24. Poul-Henning Kamp:

    What surprises me is that people still hang so much onto standard deviations, when extreme events are much more powerful witnesses to change in the underlying probability density function, be it gaussian or not.

    Given that JASON nailed this in 1992, albeit not in peer-reviewed literature, I’m amazed that nobody has taken up where they left.

    See: http://www.fas.org/irp/agency/dod/jason/statistics.pdf


  25. Hank Roberts:

    Jim’s inline response to LarryL above talks about the various factors that make a difference

    The farmers watch this.
    Planting a bit early, if the fields are dry enough to support farm machinery, can improve results — but that outcome depends on having enough soil moisture, and having no peak temperature during the summer high enough to stop seed from forming.


    If a smaller than normal portion of the 2012 corn crop is planted late, expectations should be for an average U.S. yield as much as two bushels above trend unless there are offsetting factors. One of the potentially offsetting factors is the dry soil conditions at planting time in portions of the western Corn Belt. Actual yields in 2012, like all years, will be most heavily influenced by summer weather conditions.

    Issued by Scott Irwin and Darrel Good
    Department of Agricultural and Consumer Economics, University of Illinois”

  26. jgnfld:

    @16 You make my point quite clearly: It takes education to see things quantitatively. Making the point for those lacking these two makes for a hard argument

  27. Andy Revkin:

    Mike Roddy, above, would do well to review John Michael Wallace’s publication record before casting stones. )Click here: http://www.atmos.washington.edu/wallace/JMW_Publications_09.pdf )

    Here’s a section from his EOS piece:

    Arguing about whether or not today’s extreme events are early indicators of climate change does nothing to advance the priority of global warming and other pressing environmental issues on our national policy agenda. The real significance of extreme events is as harbingers, not just of a changing climate but also of a changing world in which human society and the infrastructure that supports it are becoming increasingly vulnerable to natural disasters. The mounting disruptions in their wake reveal the progressive deterioration of our planetary life-support systems. Extreme events are, indeed, teachable moments: “wake-up calls” that an environmental crisis of global proportions is imminent—much more so than the subtle and sometimes ambiguous early warning signs of global warming might lead us to believe.

  28. Brian Morsony:

    @9 I think LarryL had a good question, that never really was addressed – Would a similarly extreme heat wave in summer produce a similar increase in temperature relative to the (monthly) average?

    To use a local example, on March 20th in Madison, WI it was 83F, about 40F above the March average (42.8F). This was also a record high for March, breaking the previous record of 82F set on March 29, 1986 and March 31, 1981. For the sake of argument, let’s call this a 5-sigma event.

    Would a similarly extreme 5-sigma event in July (average temp. 82.1F) produce a day with a high of 122F? A 122F day in July seems (to me) much more unlikely than an 83F day in March, even though they are the same number of degrees above average. Maybe a more reasonable expectation for a similar event in July would be 108F, 1 degree above the all-time high of 107F? Would it take a much more extreme event, say 8-sigma, for Madison to have a 122F day in July?

    [Response:Right. You use the standard deviation of the relevant season, not one from a different season. This is actually another point that I meant to raise in response to the comment about the Black Hills data. You don’t compare the absolute numbers to evaluate equivalency of (or lack of) extreme events across seasons, you compare the deviations from the relevant seasonal means.–Jim]

  29. Hank Roberts:

    PS — if you follow the link in the quote above, and look at the range of outcomes — the worst case is quite bad. That’s for one species (corn) in quadrants of one state (Iowa), based on the historical climate.

    I haven’t found whether they’ve worked out worst cases for the new climate that we’re heading toward.


  30. kramer:

    For the year-to-date, there have been 14,737 warm temperature records set or tied, compared to 1,296 cold records — a ratio of about 11-to-1.

    What was the global ratio for the year to date?

  31. Paul S:

    Andy Revkin – I agree with your thoughts about Mike Roddy’s prejudice regarding John Wallace.

    I don’t understand your characterisation that this post was ‘well countered’ by Wallace’s piece. They seem to be about different things: Wallace’s article is about communication strategies; Stefan and Dim’s post is about concepts used to understand extreme weather events within climate regimes.

  32. tpinlb:

    What do you think of the new paper by Solheim, Stordahl and Humlum, “The long sunspot cycle 23 predicts a significant temperature decrease in cycle 24,” in Journal of Atmospheric and Solar-Terrestrial Physics?

  33. Hank Roberts:

    for tpinlb:

    type “humlum” in the box in the upper right corner labeled “Search”
    to find the answer:


  34. Dan:

    re: 32. Here is the abstract from http://arxiv.org/pdf/1202.1954v1.pdf:

    “Relations between the length of a sunspot cycle and the average temperature in the same and the next cycle are calculated for a number of meteorological stations in Norway and in the North Atlantic region. No significant trend is found between the length of a cycle and the average temperature in the same cycle, but a significant negative trend is found between the length of a cycle and the temperature in the next cycle. This provides a tool to predict an average temperature decrease of at least 1.0 ◦C from solar cycle 23 to 24 for the stations and areas analyzed. We find for the Norwegian local stations investigated that 25–56% of the temperature increase the last 150 years may be attributed to the Sun. For 3 North Atlantic stations we get 63–72% solar contribution. This points to the Atlantic currents as reinforcing a solar signal.”

    1. This was not a study of *global* temperatures but of just Northern Europe and Scandinavia. In other words, a small areal sample set.
    2. “…the last 150 years…” The global warming that we are concerned with is the warming that has occurred since the 1970s, not over 150 years. Back then, natural causes were the dominant forcings on global temperature trends. But recent warming trends can not be explained by natural causes/forcings alone. The warming since the 70s can only be explained when the additional forcings from man-made greenhouses are considered. Furthermore, the current global temperature anomalies when compared to the climatic normals are well within the projected model ranges.
    3. You can be certain that various anti-science, anthropogenic global warming denialist web blogs and op ed writers (with no scientific background) will take this study and trumpet it from the hills, completely out of context in order to continue to be disingenuous and to purposely mislead people.

  35. Clark Lampson:

    Those commenting on LarryL’s question regarding extreme heat in Summer are missing a very fundamental thermodynamic issue: In the winter for a given area, significant heat can be transported into the region, because much warmer temps exist elsewhere on the globe. That is not the case for many regions in their local summer.

    The symmetrical question would be what sort of extreme cold spells could one see in the summer.

    [Response:Yes, but the point I’ve been trying to make is that it’s not the absolute magnitude of the anomaly that’s important, it’s the relative anomaly, as measured in standard deviations from the seasonal (or weekly or monthly or whatever) mean. That’s what organisms are adapted to tolerate. You shouldn’t use the absolute magnitude to evaluate similarity of “extreme-ness” between different seasons–it just doesn’t make any sense. This seems pretty basic to me–Jim]

  36. Susan Anderson:

    “one of the country’s most eminent climatologists, John M. Wallace” (publications date from 1964):

    Wikipedia John Michael Wallace is a professor of Atmospheric Sciences at the University of Washington, as well as the former director of the Joint Institute for the Study of the Atmosphere and Ocean (JISAO)–a joint research venture between the University of Washington and the National Oceanic and Atmospheric Administration (NOAA). His research concerns understanding global climate and its variations using observations and covers the quasi biennial oscillation, Pacific decadal oscillation and the annular modes of the Arctic oscillation and the Antarctic oscillation, and the dominant spatial patterns in month-to-month and year-to-year climate variability, including the one through which El Niño phenomenon in the tropical Pacific influences climate over North America. He is also the coauthor with Peter V. Hobbs of what is generally considered the standard introductory textbook in the field: Atmospheric Science: An Introductory Survey. He was the third most cited geoscientist during the period 1973-2007.

    A further look via Google finds Dr. Wallace promoting positions similar to Andy Revkin’s, inclusive of energy exploration including extreme fossil fuels, and he is cited as being not entirely unsympathetic with Dr. Lindzen, not enough to condemn but there it is.

    His textbook, written in 1977 and revised in 2006 (Amazon) is said to be one of the best on meteorology around. He appears to encourage an energy quest. I am not qualified to guess at the quality of his current research on cycles and so on.

  37. Thomas:

    To jump in on LarryL’s quetion. I can make a simplistic argument in favor of lower warm season variance than cold season variance. (1) Postulate that on any given day a locale experiences the expected seasonal temperature of some point at the same longitude, but which is displaced north or south depending upon anomalous circulation effects. Then if we assume the distribution of this north south variance is the same, the expected variance should be proportional to the north south climatogical temperature gradient.

    Of course Jims observations about the potential buildup of nonlinear effects from the state of the ground (soil moisture, vegetaion, snow/ice cover etc.), is still valid. We can’t rule out that these effects could throw a monket wrench into my simplistic explanation of seasonal variance.

    I’m not convinced that the T distribution has to be unimodal. There certainly exist nonlinear phsyical which exhibit quasi bistable behavior; the earths magnetic field is one such system. Is there a good argument for why weather is different in this respect?

  38. Susan Anderson:

    In considering the potential for increased temperatures in summer, don’t forget the acceleration of the increase in ocean temperature.

  39. sidd:

    Mr. Hank Roberts wrote on the 26th of March, 2010 at 2:03 pm:

    “The farmers watch this.
    Planting a bit early, if the fields are dry enough to support farm machinery, can improve results — but that outcome depends on having enough soil moisture, and having no peak temperature during the summer high enough to stop seed from forming.”

    There also is sumpn about crop insurance not kicking in unless you plant after the last frost date…

    And speaking of distributions, i notice that the TRMM global precip data are much narrower than gaussian, with long tails, and the mode is moving toward lower precip, while both extremes are increasing…


  40. Edward Greisch:

    Note that the last graph has its own RealClimate post at:

    Question: How far away from the poles can Rossby waves have an effect?

  41. Chris Dudley:

    Larry (#9),

    Northern Hemisphere winter has a broader range of variability than Northern Hemisphere summer. Fig. 2 here: http://www.columbia.edu/~jeh1/mailings/2012/20120105_PerceptionsAndDice.pdf shows this. So, the variability depends on season. In the same paper, it is shown that 3 sigma summer seasons are covering a larger fraction of the surface of the earth than they used to. The next step would be 4 sigma perhaps. Let’s place that where sigma is 1 C. And lets have a three week heatwave be what makes the summer so warm. Then the heatwave will be about 16 C above normal. If normal is about 23 C then we’d be at about 39 C or 102 F, quite a lot for the Midwest. 115 F is the hottest ever recorded for St. Louis. If you pack the offending heatwave into 2 weeks, you can hit that record for the duration.

  42. MIke Cope:

    I stumbled upon the following, from a primer on entropy by Rishidev Chaudhuri and Jason Merrill

    “Adding more energy to a system usually increases the number of states available to it. This is both because with more packets of energy there are more ways to distribute them between the members of a system, and because more energy makes high energy states accessible in addition to lower energy ones.”


  43. GSW:

    It’s a mammoth task I know, but has anyone ever published a study on the spectrum of record Hot and Cold events, either for the US or Globally, say over the last 100yrs?

    It would be satisfying to get some confirmation of the theory vs real world data.

    At the moment these records are very anecdotal and the significance attributed to them is very short lived. Over the last few years there have been regionally significant 100yr Cold events (as well as Hot) recorded in both Russia and China for example. Each event stands on it’s own however, without context, has anyone ever tried to the analysis?

  44. Dan H.:

    The variability in the Hansen paper has not change; it is simply that the mean has moved. Scrolling down each column of graphs in Fig. 1, the average JJA temperature has increased by ~0.65C (more than one sigma higher according to Hansen). Therefore, sigma events should be calculated for the new mean, not the old (using a similar mean, 3-sigma events such be occurring at the same rate as 2-sigma events did 50 years ago). The standard deviations have not changed shape over the past three decades, only shifted higher by one sigma (Fig. 9).

    Hansen does show support for our statements that the recent warming experienced in the Midwest is much more likely to occur in winter than summer due to “the huge difference of temperature between low latitudes and high latitudes in winter. This allows the temperature at a given place to vary by tens of degrees depending on whether the wind is from the south or north.” Similar to Jim’s statement about lower standard deviation in the summer.

  45. Kevin McKinney:

    #42–That seems quite insightful–a really good summary comment.

    Warning: random, uninformed musings ahead!

    The counterargument in terms of climate would seem to be the notion that the temperature gradient between poles and tropics is supposed to lessen, due to ‘polar amplification.’ Intuitively, you’d think that that would mean fewer energetic ‘states.’ But maybe not?

    It also occurs to me that these blocking events–and even more so the phenomenon of the WACCy winters, seen in 2009 and 2010, with “Warm Arctic, Cold Continents”–represent atmospheric mixing in action, essentially. So, maybe part of the process leading toward those lessened temperature gradients?

  46. Ray Ladbury:

    It is not that I despair of identifying “change,” but rather of identifying it in precisely the portion of the pdf we know least well. A one in 10 billion year event has finite probability of being realized for both the original and the changed pdf. How would we tell the difference between them? How would we know that a one in 10 billion year event for the original distribution corresponds to a one in a billion year event for the changed pdf? This is why good actuaries are so well paid–it’s more an art than a science.

    [Response:Ray, I agree that distinguishing those two states would be essentially impossible with any real world climate data of any relevance. It’s always going to be more difficult to identify changes in the tails compared to some measure of central tendency, I get that. And in a system where you have ~continuous change, rather than a definite step from one stable equil. state to another, you have complications in determining what the two relevant distributions to compare are exactly (though I think that’s a relatively minor issue). But you do need some decent idea of the shape of the original state’s distribution, including the tails. If you then have evidence that includes (1) a shift in the central tendency and (2) increasingly frequent observations of events going over x sigma, over some decent sample of space or time or both and based on the best estimated shape of the original distribution, then it is at the very least, reasonable to assume that the former tails have shifted +/- in concert with the rest of the distribution; that is to say, the entire original distribution has shifted. If the central tendency does not appear to have shifted, but some other higher moment has changed, say an increase in the variance, then you’re into deeper water I imagine, but still approachable given a decent sample size I would argue. So yes, you don’t know the changes in the tails with the same confidence as the middles, and you never will, but you can have some pretty strong and defensible clues based on the totality of the evidence coming from the estimated changes in various parameters of the distribution. And also, we are dealing with events that are much more probable than your example–1 in 200 years say or similar orders of magnitude. That’s how I look at this issue.–Jim]

  47. Paul S:

    Northern Hemisphere winter has a broader range of variability than Northern Hemisphere summer.

    One good way to see this is in the HadCET (Central England) annual cycle. Note the percentile ranges are considerably broader in Winter compared to Summer.

    One further point of interest here is the min and max annual cycles. There is sharp drop in maximum temperature after Summer but the the change in minimum temperatures is on average pretty slow and highly asymmetric.

  48. grypo:

    Andy Revkin referring to this as a “viewpoint” piece that has been “countered” by Wallace is just wrong. What Wallace is saying is that discussing extremes and man-influenced climate is fear-mongering and therefore we should stress something else. He’s also saying that “opponents” can exploit the inability of exact attribution statistically.

    In other words, shut up scientists, you’re messing up Revkin’s environmental narrative.

  49. grypo:

    link to Wallace’s opinion piece

  50. Chris Dudley:


    Thanks for that link.

    This bit seems out of date with regard to heatwaves:

    “Even in the presence of climate change,
    extreme events do not occur often
    enough to enable scientists to track
    decade-to-decade changes in their sta-
    tistics in real time, as they successfully
    do with more aggregated quantities
    such as global mean temperature and
    sea level [Palmer and Räisänen, 2002]

    “Realtime” treatment given recently by Hansen et al. seems to answer, and also for the prior bullet’s mention of Russia’s heatwave.

    It seems to me that it is a mistake when writers bundle together events with varying levels of attributional certainty. Heatwaves are more certain than deluges which may be more certain than droughts. But too often tornadoes or hurricanes are included, called uncertain and that uncertainty applied backwards to the whole list. Grammatically it may be correct, but procedurally it isn’t. Not saying there is that much bundling going on here, but there is some.

    I also seem to spy a strawman. Discussing attribution, is not the same as taking extreme events as indicators that warming is occurring. We start with the problem of attribution, these events are not signs as in a Shakespeare tragedy. The warming is already measured, these extreme events are expected consequences.

  51. Hank Roberts:

    > the temperature gradient between poles and tropics …
    > lessen, due to ‘polar amplification.’

    Held and Soden, Robust responses of the hydrological cycle to global warming; J. Climate 2006, (cited by 577)

  52. GH:

    So if the mean temperature is going up everywhere, why don’t we have heat waves everywhere too? I think I know the answer, but want to hear your viewpoint.

  53. Hank Roberts:

    > This bit seems out of date with regard to heatwaves
    > 2002

    Bingo. That used to be true, a decade ago.

    Progress furthers.

  54. Harold Brooks:

    Looking at the paper, I found it odd that “Most active tornado month on record (April) since 1950″ is listed as a meteorological record-breaking month and then an impact is listed that wasn’t associated with that event. The Joplin tornado, with 158 fatalities, occurred in late May, following what was, by many measures, the quietest first three weeks of May on record. Meteorologically, the Joplin tornado was a “typical” violent tornado and was very similar to a nearby tornado from 2008 with the exception that it hit a population center of 50000+ people, rather than 400.
    Given that the literature contains little or nothing to support that tornadoes will become more frequent or stronger, their inclusion in the paper seems odd. In looking for a tornado extreme in the last decade, it would have been just as appropriate to list 2003, which went longer at the beginning of the calendar year before a tornado than any year on record

  55. SecularAnimist:

    Andy Revkin wrote: “review John Michael Wallace’s publication record before casting stones”

    The article by Wallace that Andy Revkin recommends is not a scientific article about climatology or meteorology, but an opinion piece about how scientists ought to communicate with the public regarding the relationship between anthropogenic global warming and extreme weather events. As such, Wallace’s scientific publication record has little bearing on the merits of his opinions regarding communication strategies.

    As far as I can tell, Wallace seems to be saying that scientists should not suggest to the public that the increasing number of extreme, and indeed unprecedented, weather events occurring simultaneously all over the world, events of exactly the sort that climate science has predicted would result from anthropogenic global warming, are in any way linked to global warming.

    I admit that I find it hard to be sure of exactly what Wallace is saying. In particular his closing paragraph, which Andy Revkin quotes, appears self-contradictory and incoherent.

  56. Paul S:

    SecularAnimist – I think Wallace’s point is that highlighting record meteorological events as evidence of global warming, or attributing individual events to global warming may be a losing communications strategy due to the difficulties and potential for subjectivity with such assessments. See Harold Brooks post above for a possible example – is it an extreme event when there are fewer tornadoes than normal?

    Wallace’s article is mainly proposing that climate scientists should instead place extreme events within a wider context – alongside other growing environmental, demographic and resource issues – to provide a more vivid window on the future.

    I agree this seems contradictory. Not sure how you can suggest an event is a ‘harbinger’ without attributing it to a cause or causes.

  57. Ric Merritt:

    Brian Morsony #28, plus Jim’s response in line, make a good point about variation that itself varies by season. (Hello Brian from a fellow Madison resident.)

    Using standard deviations taken from data by month, or season, is informative but, I’m sure, doesn’t capture all the information in the data. For example, the Madison 83F broke the March record by 1F (and note other places that broke daily records by 20-30+F, and broke *April* records in March), but did so 10 days earlier than before, in a season with rapidly increasing averages. So the delta of 1F doesn’t tell the whole tale.

    Data for 1.5 centuries is enough to make the SD for a given day of the year of some use. I suppose, given the gradual seasonal changes, there would be a good way to use data from sliding windows around each date, with the window width determined from the data itself, but deciding just how is beyond my Statistics 101 expertise.

  58. grypo:

    Look, IMO, it’s almost irrelevant what Wallace was supposed to be saying in that final paragraph. It simply doesn’t deal with attribution science at all and shouldn’t be used by journalists to contradict a review of the science of extreme weather attribution. And it is not the job of scientists or journalists to be armchair psychologists and developing communications strategies that soften the blow. Perhaps finding a better way to tell people how bad it’ll be is laudable goal, but doing a tap dance around the issue is clearly not the way to go. If they think they’ve figured this quandary out, they are just wrong. Their job is to get the information out there in the meantime. This is the same type of thinking that leads to US foreign wars being covered like Playstation games.

  59. Dan H.:

    Ric, et.al.,
    Has anyone looked into the cold spell over NW Canada, Alaska, and NE Russia? The magnitude appears to be equal and opposite in nature, although the extend cannot be ascertained from the Mercator projection. Are these related?


  60. Ron Manley:

    For several decades hydrologists have spoken of the Noah and Joseph effect; ‘Noah’ because extreme events, like ‘the flood’, do not follow the pattern of lesser floods; ‘Joseph’ because climate variables are auto correlated. One of the fundamental tenets of statistics is that the data should come from a homogenous population. When an extreme event occurs it is often an event from a different statistical population. For example, in Oman for most of the country for most years, rainfall is mainly in the winter. Sometimes the monsoon, which normally touches just the southern part of the country, reaches further north and heavy rains occur in the summer: an event which is hard to predict from an analysis of ‘normal’ rainfall.

    Similar factors could apply to droughts. For example a ‘standard’ drought might have anticyclonic conditions with gentle wind bringing bring air from a warm area; in ‘normal’ years the drought might be broken by wetter, colder air moving in from the opposite direction. A severe drought could be caused by a change in circulation patterns bringing air from a ‘hot’ rather than a ‘warm’ area or diverting the ‘wetter, colder’ air somewhere else.

    This means that a small change in weather circulation linked to other climate changes could precipitate a (different type of) drought way outside past experience. If those changes in circulation are as predicted by climate models then the drought can be attributed to climate change. If they are not, it may just be natural variation.

  61. John Pollack:

    Brian @28 and Rick @55 To get a practical idea of what kind of extreme would result if these anomalies were in July in the U.S. Midwest, it’s instructive to look at 1936 and 1995. The former represented surface temperature extremes obtainable in a severe drought, the latter when the ground was fairly moist before the event. Surface temperatures were lower in 1995, but dew points were really extreme (low 80s F, 27-30C) and a lot of people died in Chicago.

    From another perspective, it would be interesting to apply the anomaly in sigma from the current event to July values of 500 mb height and 1000-500 mb thickness (equivalent to average layer temperature.) The forecaster’s crude rule of thumb for the latter is to take the thickness in dm, subtract 500, and then add 15 for the max temperature in degrees F. That’s for moist ground. If the 500 mb height was over 6000m we’d be in new territory.

  62. wili:

    I think I just heard on the radio that the IPCC is releasing something on this subject today. Does anyone know anything about that? Is it out yet?

    (I see that yesterday’s DailyKos mentioned it too:

    http://www.dailykos.com/story/2012/03/27/1078251/-IPCC-SREC-Report-Release )

  63. Mark A. York:

    Oh boy. Yet again with the no warming for 10 years meme. 10 of the hottest years on record as I see it.


  64. Chris Dudley:

    I started out in the thread discussing Jeff Masters recent comments on shifting means and probability of the recent heat in the Midwest. I pointed out that when the mean shift is small compared to sigma, it may be difficult to make a practical application of what Dim and Stefan have done here. But, I noticed in answering Larry that sigma is seasonally dependent. In the summer it is smaller than in the winter in the Northern Hemisphere. So, I reviewed the gistemp 100 year trend maps for the four seasons just now and it looks as though the mean shift is pretty similar between them both in magnitude and in spatial distribution.

    In the summer, where sigma is smaller, the situation could look more like the illustrative graphs presented here where the mean shift and sigma are comparable. If the mean shifts by 0.7 sigma or so, then these graphs describe the situation today for one season at least. So, my comment about lack of practical application may only apply in more variable seasons for now.

  65. Doug Proctor:

    [Response:Our approach in that paper assumes a probability distribution that shifts towards warmer temperatures, but is otherwise unchanged – just like the simple example given in the second graph above. Something like an extreme cold event related to sea ice loss obviously can not described in this way – it is a great example of a highly non-linear mechanism. stefan

    How can a sea-ice loss, which exposes sea-water that must be no colder than -2C, cause a serious cold event? The presence of open seas has a moderating influence on temperatures, as any coast dweller understands.

    A “warm” event that reduces sea ice extent cannot generate an atmospheric circulation that is colder than the temperature of liquid seawater.

    Unless “warm” is now “cold”.

  66. Daniel J. Andrews:

    Thank you! That corrected some of the misconceptions I had.

  67. Kevin McKinney:



  68. wayne davidson:

    #59, Dan H, That is 1/2 of winter’s normal extent. There is less of it going around the North Pole. Simple enough??

  69. SecularAnimist:


    Geneva, 28 March 2012 – Evidence suggests that climate change has led to changes in climate extremes such as heat waves, record high temperatures and, in many regions, heavy precipitation in the past half century, the Intergovernmental Panel on Climate Change said today.


  70. Eric Rowland:

    wili @ 62, The report is available here:


  71. Tokodave:

    Sigh, another day, another stupid WSJ editorial…it’s almost as predictable as high temperature records. You might think that the WSJ would be interested in a fact based reality. You would be wrong.

  72. Dan H.:

    That is not telling me much. Are you saying that one half is balancing the other, as to the reason for the cold equaling the warm?

  73. Kevin O'Neill:

    Doug H. – You are exactly wrong. A warm event can displace/block colder air whose temperature is unrelated to the temperature of sea water. It is this type of effect that creates the Warm Arctic/Cold Continents pattern.

    You need to read Dosbat and the papers Chris R has been discussing.

  74. Kevin O'Neill:

    Aaack – Previous comment directed at Doug Proctor not Doug H.

  75. wili:

    Thanks KM and ER. Is this the appropriate thread to discuss it? Will there be a thread dedicated to it? Or should we take it over to the open thread?

  76. Hank Roberts:

    > Doug Proctor
    > sea ice loss … cold event


    “… decrease in Arctic sea ice area is linked to changes in the winter Northern Hemisphere atmospheric circulation … which lead to increased cold surges and snow over large parts of the northern continents.”

  77. wili:

    I see it is being discussed at ClimateCentral:


    And at ClimateProgress:


  78. Kevin McKinney:

    #74–It seems appropriate–not to say highly relevant!–on this thread to me.

    I read it quickly, and haven’t gone back over it yet. But it seemed very cautious to me–“not that there’s anything wrong with that!” It did have some hints that regional-scale modeling is starting to bear some fruit, or so I interpreted a couple of points.

    I was a bit confused on one point. It quoted various figures for increased probabilities of extreme events–1-in-2 might become 1-2, for example. But the figures for Northern high latitudes were *less extreme.*

    Given Arctic amplification, I didn’t understand why that should be the case.

  79. Kevin McKinney:

    Ack! “1-in-20 might become 1-in-2″–of course!

  80. Norman:

    I guess I have been banned from posting on Skeptical Science so I thought I would try here to see how things are.

    “That need not be the case, of course, since weather is highly stochastic and global warming can also affect the circulation patterns of the atmosphere.” from OT

    “Definition of STOCHASTIC
    1: random; specifically : involving a random variable source

    I may disagree that weather is highly stochastic. Weather seems to have some well established patterns. Record high temperatures are not so randome but occur because of certain predicatable conditions. Mostly a blocking pattern that continues to pump warm air from one area to an area that is usually cooler. In the middle of the US, nearly every low pressure system that crosses the plains will first raise the temperature above normal (in some cases by serveral degrees, by pumping warm gulf air into areas that are usually cooler) and as the low passes the area the temperature may drop nearly the same degrees below normal as what had been above normal. You can have 40 F degree temp swings in a couple of days if you have a powerful low pressure system. Because of this I question that you can use a normal curve to explain extreme weather events. My understanding for bell curves is the requirement that the variables be random. In a heat wave the temperature of day one will effect the temp of day 2 and so on, the heat will build. Each day effects the other and are linked. It is not like a dice throw where the previous throw had no effect on the next throw. In weather patterns this randomness is not the case.

  81. John P. Reisman (OSS Foundation):

    I decided to make a ‘Weather Intensity’ page on OSS


    Relevant comments and criticisms welcome.

  82. John P. Reisman (OSS Foundation):

    #62 wili

    I believe they will say something like:

    ‘Individual climate events can not be linked to climate change, but the increased frequency and intensity of such events is probably a result of climate change.’

  83. Norman:

    SecularAnimist @69

    Some facts to go with your “Geneva, 28 March 2012″ announcement. As a researcher it is good to look at all the information before drawing strong conclusions or seeing patterns where none may yet exist.


    I found this site to be very interesting in the current environment to proclaim that exterme weather events are proof of climate change getting worse.

    It has some major US cities and lists of exterme weather events for the entire known history of the cities. At the end of each page is a list of all the known extremes. Hot, cold, rain, snow, etc. If you really start reading the material you will see that one year is listed as the hottest year in the data base, then a few years later you have one of the coldest years. One year is the wettest, a few years later you have a really dry year. The same year has some extremes. Warmest March ever with the coldest December. If you take an honest look at historical weather events, it is far from certain you could conclude that events are getting more extreme.

  84. owl905:

    @Tokodave 71 – that WSJ opinion piece is about as a academic as a Superpac ad. Bill Happer’s background isn’t climate, and his politics radiate from his Chairmanship of the Marshall Institute.


    Where’s Elmer Fudd when you really need him?

  85. Hank Roberts:

    > If you take an honest look at historical weather events,
    > it is far from certain you could conclude …

    How far? .05 two tailed test, or what?

  86. dhogaza:


    I found this site to be very interesting in the current environment to proclaim that exterme weather events are proof of climate change getting worse.

    It has some major US cities and lists of exterme weather events for the entire known history of the cities.

    A handful of US cities are not the world.

    Odd that you’ll reject the database of world temps and suggest, that somehow, a very small number of US cities refute that record.

  87. Steven Franzen:

    @83, Norman:

    Added two words to make your statement more truthful:

    If you take an honest look at [local] historical weather events, it is far from certain you could conclude that [globally] events are getting more extreme.

    Since, as a researcher, it is good to look at all the information before drawing strong conclusions or seeing patterns where none may yet exist. My guess is that you are not a researcher.

  88. Kevin McKinney:

    #80, #83–

    “These comments are sponsored by the letters D, N, F, T & (again!) T.”

    Or so I am thinking.

  89. Norman:

    dhogaza @86

    Not sure how you formed your conclusion “Odd that you’ll reject the database of world temps and suggest, that somehow, a very small number of US cities refute that record.”

    That was not the intent of link to the cities I posted. The point of the Original Thread is that global warming is pushing the globe to more extreme weather patterns. By showing the historical variablility of weather patterns and extremes (one year has a very cold month, but also one of the warmest month…or the variability of snow and rain from year to year or even within a year…a bad drought in one month then heavy rains a few months later…Texas has experienced this most recently).

    By viewing the history of extreme events (heat, cold, wet, dry) in this selection of cities, you can see that extreme events have been taking place the entire historical record.

    Here is a link to the entire US. December 1909 76% of the United States was very cold. In March 1910 (only a few months difference) 92% of the United Stats was very warm.

    (source of data) http://www.ncdc.noaa.gov/temp-and-precip/uspa/index.php?area=warm-cold&month=0&year=1920

    I would like to look at global records but they are not so available as are United States data. r

  90. Chris Dudley:

    Here’s an item on conservative’s falling trust in science: http://scienceblog.com/53012/study-conservatives-trust-in-science-has-fallen-dramatically-since-mid-1970s/

    Maybe explaining things clearly faces challenges more on the receiving side than on the sending side? Math can be tough, but maybe that is not the real problem?

  91. SecularAnimist:

    Norman wrote: “SecularAnimist @69 … Some facts to go with your ‘Geneva, 28 March 2012′ announcement. As a researcher it is good to look at all the information before drawing strong conclusions or seeing patterns where none may yet exist.”

    Please present your “facts” and your lecture on “looking at all the information” to the IPCC. All I did was provide a link to the IPCC report.

  92. Daniel Bailey:

    @ Norman

    As the primary moderator at Skeptical Science I must interject: Norman was indeed banned from SkS. What is missing (as Paul Harvey would say) is the rest of the story:

    Over the course of more than a year, Norman established a habit of hyper-focusing on selective, local weather events and single-point weather records in what ended up being a concerted effort to sow the seeds of apparent uncertainty among global climate data records. He single-handedly hijacked more than a dozen threads, extending their life-span from dozens of comments into the many hundreds with what amounted to “But what about __________?” statements. He was given perhaps more attention from moderation and helpful participants, and more leeway, than any single commentator in the history of SkS. (And that includes P**tech)

    Norman holds the distinction of being the only SkS participant to receive a “time-out” (a rescinding of posting privileges [NOT a ban] for 2 weeks, with a reinstatement of those privileges after the time-out expired).

    After his time-out, his posting history became much more circumspect. But with the reinstatement of posting privileges of certain others participants, he became re-emboldened. His earlier behaviour reasserted itself even more strongly, to the point of being habitually off-topic. After yet more warnings his posting privileges were rescinded. This time for a longer period of time.

    Again I must point out, Norman was given more latitude, due process and chances to ameliorate his aberrant choice of posting behavior than any other participant at SkS. That he did change when forced to do so further demonstrates that the return of the (aberrant) behavior when standards were lax was willful.

    Apologies to all for being off-topic.

  93. Ray Ladbury:

    Norman@80 & 83
    Oh look! Norman has rediscovered weather.

    No, Norman, from your website with its limited information, you most definitely could not draw GLOBAL conclusions. However,if you look at the data for the GLOBE, it is easier to do so.

    Perhaps global climate change would be easier for you to understand if you looked at the GLOBE and and Climate (rather than weather) and at the deltas.

  94. John P. Reisman (OSS Foundation):

    #80 Norman

    If you’ve been banned then it may be because you present really bad ideas and interpretations on a regular basis. A little bit of knowledge and inadequate understanding do not an expert make.

    If you disagree that weather is random and therefore unpredictable, then you must have a magic crystal ball that predicts precisely when certain types of weather occur; such as in 27 days it will rain at 2:33 pm at a particular place but only for 30 minutes, and then a tornado will hit in this particular place and follow this particular track and hit this particular town and miss this particular trailer park.

    So unless you are a god, I doubt you can predict when weather will occur all around the world with any degree of precision. Now, climate, climate is much more predictable. For example, we know it will be generally colder in winter and warmer in summer.

    #83 Norman

    If New York, for example, represents global temperature in your mind then why would not Antarctica represent the climate of the Sahara desert. I mean everyone knows that they are both the same temperature right because the weather and climate of a single place represents the planet. Right?

    So you rely on a narrowly scoped interpretation to represent the planet and have no idea how stochastic weather is, while simultaneously expressing arrogance that you know what you are talking about.

    Why don’t you post your full name as many here do. Or are you afraid of looking ridiculous for using such poor logic?

  95. Aaron Lewis:

    Discussion between Ray and Jim:

    This is an issue of extreme importance and urgency in the design and construction of infrastructure.

    For example the basis of engineering design for a public water supply in Texas was has changed as a result of the recent drought. Even when the drought ends, we will not know how frequent such droughts will be in the future as the Arctic warms and atmospheric circulation changes.

    Statistical approaches can look a few years into the future. However, with planning, permitting, finance, design, and construction, it may take 10 years to put a new water supply in place and have it operational. Then, a water supply is expected to last for generations. In a time of climate change, statistical approaches based on past data, cannot look 20 or 50 years into the future to see what conditions climate change will impose on the water system.

    In the past, the paradigm would have been to simply say we can expect such a drought at a particular frequency. (i.e., Climate change was very slow.) Now, we have nonlinear conditions where we have to engineer infrastructure on the assumption that some extreme conditions will be more frequent in the future than they were in the past (Fat tailed PDFs), and some conditions will be less frequent. For example, cold days may be less frequent, but extreme cold events more intense (long tailed PDFs). Thus, we will see a shift in average temperature, a widening of the PDFs, and the PDFs are likely to become highly asymmetric, all within the foreseeable future. Moreover, note that PDO offers two semi-stable climate states meaning that weather event PDFs may have 2 or more nodes; and since weather effects can be the result of wind and rain or wind and snow or in the case of freezing rain the temperature of different media, weather event PDFs may be multidimensional.

    Changes in weather PDFs make planners, engineers, and decision makers – dither. Dithering is is expensive. And, planning and building to standards not warranted by past climate conditions is a very hard sell.

    The result is that we are going to waste a lot of money designing and building infrastructure that will not withstand the rigors resulting from global warming. (There are not as many cold days, so to save money we do not bury the water pipes as deep. Then, when we do get the extreme cold event, all the water pipes freeze and burst. To save money, we do not build enough water capacity, and run out of water for months on end every few years. Those kinds of planning/engineering errors can kill a community.)

    We are going to waste capital repairing stuff (to the old design) that would better be rebuilt to withstand the rigors resulting from global warming.

    However, the single largest cost from the shift in average temperature, widening of the weather PDFs, and the weather PDFs’ asymmetry will be in agricultural production. Modeling agricultural production with normal weather PDFs based on old data is like a physicist modeling egg production by assuming spherical chickens. It is not useful.

  96. John P. Reisman (OSS Foundation):

    Re. #92 Daniel Bailey

    Sounds like Norman is vying for Borehole status.

  97. Susan Anderson:

    Chris Dudley@~90
    I think it’s a question of fashion. When I was young it was eggheads, nobody liked ‘em. Reagan introduced “I have read it and I do not understand it” about his science report (sloppy perhaps, but that’s the gist). Popularity and conformity has always been more important than schoolwork, and with mega-entertainment and sports, fake life “reality” shows, and electronic access 24/7 it is now possible to ignore the arduous process of learning and the experience of acknowledging uncertainty altogether. Building up understanding and knowledge is so 20th century! And our political know-nothings are now in charge. Who needs expertise when they have Inhofe, ALEC, and the troops.

    All this carefully fed by the metastasizing nexus of conservative think tanks fueled by the vast profits of the ownership classes bent on deregulation and quarterly profits.

    Our education is out of whack, and teachers don’t get either respect or compensation commensurate with their real value. It would be laughable if it weren’t tragic that research is equated with lobbying when comparing funding.

    All this is very OT and I will understand if the moderators regard it as too political and ban or edit it. It’s another kind of heat.

    OTOH, with things getting so weird, I am finding laypeople are increasingly eager for knowledge, but the political classes are eager to distract them from those fears and feed other fears more conducive to ignorance and inaction.

    Just checked out the borehole – very informative. It’s important to remember that among the persistent distractors, some are paid for the work, though we cannot “officially” identify which ones are just fellow travelers, wishful thinkers, and groupies.

  98. John P. Reisman (OSS Foundation):

    #97 Susan Anderson

    I would like to speak with you sometime to share ideas on these topics.

    or +1-202-470-3299

  99. Norman:

    Steven Franzen @87

    “Since, as a researcher, it is good to look at all the information before drawing strong conclusions or seeing patterns where none may yet exist. My guess is that you are not a researcher.”

    You are entitled to your opinion Steven. I have been compiling information from NOAA to determine if severe weather events may or may not be increasing. One type of data I was compiling was wind speeds from thunderstorms 70 knots and above.

    I found some interesting information and consulted an NOAA meteorologist concerning the information. I will post a copy of my email and response and you can then determine if I am not engaged in proper research methodology.

    My Question: “Hi,

    I am doing some Climate research and using the NOAA “Storm Events” page as a tool. I was logging thunderstorm winds 70 knots or above per year starting with 1980.

    I am wondering if many more storms became a reality or if reporting methods have taken on a new evolution of detection (maybe using doppler radar).

    From 1980 to 1993 there is a steady amount of storm events with wind speeds 70 knots and above in the 100 range. Then after 1993, in 1994 and 1995 you have a doubling of event count. After that the numbers double again into the 400 event count and in the last few years (2008 to current) the number is now in the 600 + range of events.

    Either the weather is getting more extreme at some exponential rate or the rapid increase in numbers is caused by better detection methods.

    Rather than guess at the answer I was hoping to get a response from an expert in the field.

    Thank you so much for your time. I am hoping you may be able to answer this email.

    Norman Grinvalds

    The response to my email: “Hi Norman:

    Thanks for your e-mail. It is a very good question…

    The data contained within Storm Events Database is collected from the Storm Data Product. There have been many reasons for the increase in events, most likely is the increased interest in severe weather as well as the collection techniques utilized by the 124 National Weather Service Forecast Offices (NWSFOs)

    There has also been an increase in population in rural areas and technological advances in computing and communications. For example, Storm Data from 1959-1992 consisted of typing (using an old typewriter) the storm reports on a NWS form F8. This took a while and only confirmed, verified reports were considered worthy to be included due to the time factor. In 1993 (a date you mentioned), the NWS began using WordPerfect 5.0 and a computer, allowing for more reports to be added with less time consuming work. The use of Newspaper clipping services were also utlized, providing the NWS office several more reports that might not have been reported directly to the NWS office. In 1996, the NWS moved to a database program (Paradox 5.0 then 7.0) and saw the increase of reports generated by the use of more weather spotters, using local law enformcement officials and emergency managers to assist in the collection and dissemination of Storm Data through Local Storm Reports (LSRs) and the advances in the newest computer system, the Advanced Weather Information Processing System (AWIPS), which also allowed offices to coordinate better as thunderstorm cells tracked across multiple County Warning Areas (CWAs). And your other assumption is also correct. The advances in radar and satellite have allowed for more detailed areas being targeted for post storm damage surveys.

    In October 2006, the NWS began using a web-based entry into Storm Data, making the entry of events even easier and less time consuming.

    In addition, global climate change can be considered as possible factor in the increase in more extreme weather, prompting additional storm reports.

    Wind reports in general, are either measured (by an anemometer) or estimated (by damage caused). There have been several advances in anemometer technology, but I do not believe there has been a substantial increase in anemometers since early 1990s when the Automated Surface/Weather Observation System (ASOS/AWOS) were deployed. Vane (propeller) and cup type anemometers have been replaced with ice-free sonic anemometers at most locations. Install dates are located here: http://www.nws.noaa.gov/asos/pdfs/IFW_stat.pdf

    I would have to say that it is a combination of many factors that have been responsible for the spike in the number of severe weather reports and thunderstorm wind speeds/gusts.

    Regards from NCDC,”

    Stuart Hinson

  100. Norman:

    John P. Reisman (OSS Foundation) @94

    “If you disagree that weather is random and therefore unpredictable, then you must have a magic crystal ball that predicts precisely when certain types of weather occur; such as in 27 days it will rain at 2:33 pm at a particular place but only for 30 minutes, and then a tornado will hit in this particular place and follow this particular track and hit this particular town and miss this particular trailer park.”

    I do not think you are understanding the point I made about weather. Long term prediction of weather events is not currently possible but that does not mean weather events are random. With a dice throw each toss is not dependent on the previous throw. This is true randomness. With a high or low temperature reading or record setting events, they are not random fluctuations in the environmental field. High temperature events can occur when a low pressure system pumps warmer air into a normally cooler area. The rise in temperature is not random but a predictable phenomena. Weather forecasters can indeed predict the temperature will first rise (days in advance) and then fall by observing the motion of a low pressure system.

  101. Norman:

    Daniel Bailey @92

    Thank you for letting me know the thoughts on your end. I think the final reason you banned me was because I was challenging the Munich Re graph used as proof that weather events were getting worse because of AGW.

    I am not sure why the data I was posting was off topic for that particular thread.

    You are a good moderator and have been quite helpful to me on an individual basis (as you described in your post). I thank you for this.

    You do believe I have an agenda (perhaps to misdirect). My goal is to keep thought and thinking alive. When I see some thread posted on Skeptical Science with no challenge of the premise I will take a stab at it. My thought process may not be the cleanest and may annoy disciplined thinkers like yourself, but the goal is always to keep thinking going. Questioning and challenging ideas and topics. Especially ones that assume weather events are getting worse without a really and detailed study of past events.

    Also moderators, sorry if this post is off topic. If it goes into the borehole Daniel Bailey may never see it.

  102. Chris Dudley:

    Hi Susan #97,

    I’m not sure just how good that study is, but it was interesting that it seems to be the better educated conservatives who are moving away from science there. Conservatives have long attacked liberal education while benefiting from it: http://en.wikipedia.org/wiki/The_Closing_of_the_American_Mind#Summary but that seems to have become a habit and spilled over to hard sciences which they used to support.

  103. Craig Nazor:


    What on earth are you talking about?

    I live in central Texas. No one here considers one dry month a drought. No one here considers “heavy rains” upon occasion, particularly in the late winter or spring, extreme weather. These things are all within the natural variability of local weather. (The actual record for rainfall in the US in a 24-hour period is 43 inches. That was a hurricane in Alvin, Texas in 1979. Hurricanes can do that, so that is really not that surprising.)

    What is extreme, and what constitutes a drought, would be the driest YEAR on record (2011). When the water source (a reservoir, Lake Travis) for hundreds of thousands of people is 60% full at a time of year when it is usually 100% full, as it is now, is extreme. Despite our relatively wet (but not record-breaking wet) spring this year, our aquifers are so depleted from a record year of drought and are soaking up so much of the rain that lake levels have been very slow to rise. If this doesn’t improve, we are in BIG trouble. That’s extreme.

    What’s extreme for central Texas is a wildfire that burns over 50 square miles of forest, and over 1,200 homes (Bastrop, Texas, 2011).

    How about the record number of days above 100ºF? Having experienced it, I would call that extreme, and I would also have to call that the summer of 2011.

    Meanwhile, our lovely Governor continues to call the science behind anthropogenic global climate change “all one contrived phony mess that is falling apart under its own weight.” I would call that statement extreme, and extremely false.

    And elsewhere – how about little appreciable ice cover on most of Lake Erie this last winter, for the first time ever? How about leaves emerging in the spring in northeastern Ohio consistently ONE MONTH earlier than they did in the 1960’s? Are these events extreme?

    The list goes on. So what on earth are you talking about? You remind me of the Wizard of Oz: “Ignore that man behind the curtain!”

  104. Norman:

    Craig Nazor @102

    “What on earth are you talking about?”

    This short article is what I am talking about. Texas did have a bad drought in 2011. Does that mean it was caused because of AGW? Possible but one should study the issue before forming an absolute position on the topic.


    Evidence exists of megadrought in your area in the past and large floods on the Mississippi. 100 years of data may not be nearly long enough to form conclusions that AGW is making droughts worse. Texas has had some bad droughts in recent times. 2011 was the worst but others were also very bad for the people living in that area. It seems Texas is prone to droughts every few decades.

  105. Daniel Bailey:

    And the modus operandi continues, unabated.

    Same program, different channel.

  106. Susan Anderson:

    Norman, if you think we need 100 years of data of the destruction of people, their homes, and their livelihoods, leaving a 100% informed but inhospitable planet no longer inhabited by most of the descendants of maximizing anti-regulatory pro-consumption dreamers and the rest of us, you’re not paying attention. This is not a laboratory or a political contest but an attempt to share what we already know about the complexity of reality home to people who can do something to improve our odds. Sorry about the gluey sentence, happens when one gets worried and sees someone pretending reality can be bent to their purpose.

    This is not new – it became blindingly clear to those paying attention in the 1980s. It’s just playing out with every detail and development occupying the higher end of the error bars as they get smaller with more of your “data” and more unintended consequences of our manipulative ways emerge.

    The only hope I see with you and your ilk clogging the conversation is that people who don’t follow science are worried sick and may – in the teaparty phrase – say they’re sick of it and won’t take it any more.

  107. Susan Anderson:

    Daniel Bailey has made the effort to provide a detailed summary of the massive kidnapping of conversations by Norman, despite extended tolerance of his detailed and skilled hijacking work. His description perfectly matches what we see here, overwhelming verbiage intended to prevent the rest of you from being productive and mislead casual visitors. Bore hole, please?

    recaptcha: some rodents!

  108. Susan Anderson:

    Chris Dudley@~102

    Chris Mooney is a favorite of mine and I’ve followed the evolution of distractionalism since the mid-oughts, but my comments were from my own observation (I was a child during the “egghead” phase). The Bloom article is interesting, but my generation got a lot of philosophy from pop music. Unfortunately some of the more creative forms seem to have been kidnapped by melismo and rage rhythms. I’m not sure the classics weren’t overdue for replacement and a lot of our troubles stem from the ideas of entitlement and exploitation inherited from the British Empire that bequeathed them to us.

    It is distressing to see the increasingly professional level of anti-knowledge promotion. Imitation may be the sincerest form of flattery, but it is heartbreaking that the truth no longer shines so clearly in comparison. Money talks, and it is advantaging itself in this conversation with the best PR it can buy. To continue in cliche, it is easier to destroy than to build, and the original may be difficult to distinguish from the copies, while the copies are more professionally distributed and promoted.

  109. SecularAnimist:

    Norman wrote: “This short article is what I am talking about.”

    No, that short article has NOTHING to do with your absurd — and patently dishonest — claims. You are just hand-waving at it.

    Dear moderators, it seems that we already have one “pet troll” around here, whose blatantly obvious efforts to waste people’s time with repetitive BS are tolerated for reasons that elude me — that being Dan H.

    One is more than enough. Can Norman’s nonsense please be directed to the Bore Hole where it belongs?

  110. John P. Reisman (OSS Foundation):

    #100 The anonymous Norman that favors single or regional event data over global…

    Two questions?

    1. Why are you afraid of posting your real name?

    2. With incased heat energy and water vapor in our global climate system due to increased radiative forcing, which is due to increased GHG production form human sources; please hypothesis, do you ‘think’ the dice would load toward more intense weather events (drought, flood, snow, rain, cyclonic activity) based on these facts, or would it become less intense?

  111. RomanM:

    I do not have access to a copy of the paper currently being discussed but I did read the earlier PNAS paper by the these authors on the Moscow heat wave. Although I have some disageements with their approach in that paper of restricting their retrospective consideration of the probabilities of such events to a single decade ( sort of like examining a jackpot win on a slot machine to a single day and ignoring the fact that no jackpot had been won in a long time previous to that), what I found particularly strange was the method for actually calculating the specific probabilities which formed the main results of the paper.
    The authors considered two scenarios for generating the record temperature sequence. The first was a simple random order structure where each ordering is assumed to be equally likely. The second involves a more complex structure which assumes a series of normal distributions with a linearly increasing trend for the mean temperature. They then calculate the expected (i.e. mean) number of records for the last decade and state:

    Next we apply the analysis to the mean July temperatures at Moscow weather station (Fig. 1E), for which the linear trend over the past 100 y is 1.8 °C and the interannual variability is 1.7 °C. Their ratio of 0.011∕y yields an expected 0.29 heat records in the last decade, compared to 0.105 in a stationary climate, giving a 64% probability [(0.29 − 0.105)∕0.29] that a heat record is because of the warming trend. If instead we use the more realistic nonlinear warming trend as shown in Fig. 1E, the expected record number is 0.85, which implies an 88% probability [(0.85 − 0.105)∕0.85] that a heat record in the last decade is due to the observed warming trend.

    What I don’t understand is why the calculated values (.64 and .88) can in any way be interpreted as genuine probabilities. If the method is correct, then in the case where the two expected values were the same, the resulting probability would be zero and this “probability” would presumably apply to whichever scenario had been chosen as the base for the comparison.
    Perhaps the authors could provide a reference which would detail the assumptions for and a scientific derivation of this method.

  112. John P. Reisman (OSS Foundation):

    Norman the anonymous that seems not to understand that the weather in his backyard or a particular region and time scale is ‘not’ global climate…

    Since you have inferred that local is global, do you know why it’s colder in Antarctica than the Sahara desert?

    And I agree, any irrelevant answers from Norman should go to the Bore hole.

  113. Norman:

    SecularAnimist @109

    “No, that short article has NOTHING to do with your absurd — and patently dishonest — claims. You are just hand-waving at it.”

    Please site evidence of my absurd or patently dishonest claims. And also while your at it, explain why the article I linked for Craig Nazor is “hand-waving”?

    What are my claims exactly that you believe are dishonest? The link I provided to Craig Nazor answers the question he asked me. He sited the nature of the 2011 drought in Texas and I demonstrated that megadroughts have taken place in that area in the past. How is this dishonest? What part of my posts are not based upon science?

    You may consider my posts trolling, I consider them questioning what has not been proven. Did you read the link I sent?

    Maybe you did not so here is the opening statement:
    “Large and prolonged departures from average precipitation (flood and drought intervals) have significant impacts on the environment and society. Current understanding of the natural cycles of flood and droughts, including changes in frequency and intensity of these cycles associated with climate variability and change, is hampered by the lack of adequate long-term records.”

    It is difficult to determine the direction of the frequency and intentsity of cycles because of lack of hard evidence. Ongoing research is taking place to try and fill in the missing data with creative proxies. Let the data determine the situation. Questioning a position should be allowed. The moderators on this site are climate scientists, maybe they will allow the questions as long as they are backed up. So far I have been backing up anything I suggest with available evidence. What evidence that I present are you so against?

  114. Norman:

    John P. Reisman (OSS Foundation) @110

    My last name is not that important. I am not a famous person. I live in a small town close to Omaha Nebraska. Grinvalds is the last name if you think it has value. I have a BA in Chemistry for Midland College in Fremont, Nebraska.

    “2. With incased heat energy and water vapor in our global climate system due to increased radiative forcing, which is due to increased GHG production form human sources; please hypothesis, do you ‘think’ the dice would load toward more intense weather events (drought, flood, snow, rain, cyclonic activity) based on these facts, or would it become less intense?”

    To answer one of your questions, cyclonic activity (extratropical anyway). Here is an article of interest.


    If you do not want to click the link.
    “Changes in extremes of extra-tropical cyclones with climate warming are less clear (Meehl et al., 2007a). Extra-tropical cyclones form and grow via baroclinic instability, getting their main kinetic energy from the conversion of available potential energy, though some contribution may also come from latent heat release. Available potential energy is proportional to the variance of temperature in the troposphere. This is why extra-tropical cyclones are more intense during winter when the temperature variance is highest. Climate models integrated with higher concentrations of greenhouse gases generally show a reduced temperature gradient in the lower troposphere of the Northern Hemisphere (NH) at least during winter because of a stronger Arctic warming. This implies that the available potential energy will decrease. With this reasoning extra-tropical cyclones might be more intense in a colder climate.”

  115. Steven Franzen:

    @99 Norman:
    My response was only to your post at 83. Because: In reply to SecularAnimist’s link to the (594 page) SREX report, you suggest that it is a good idea to look at all the information before drawing conclusions. Without any further comments from you about this report, this gives me the impression that you think the IPCC is not looking at enough information. Then you move to a few qualitative evaluations of extremely local data, before concluding:

    If you take an honest look at historical weather events, it is far from certain you could conclude that events are getting more extreme.

    This suggests that you consider your personal observations to somehow trump the extensive compiled work of many professional researchers. That is whereupon I based my guess that you are not a researcher, at least according to the standards you suggested. If you disagree, perhaps you could elucidate me on how to view “looking at all the data” in light of your cursory reference to the SREX report and your casual review of a few very local data.

  116. numerobis:

    John, Norman *did* post their name. It’s “Norman” and this handle has a known identity and reputation. They may go by Norman Grinvalds in other parts of life, or at least that’s how they signed their purported email, but so what? The total lack of any scientific sense is much more relevant to our discussion.

    My reason for responding is to note there is in fact an interesting philosophical discussion about whether God plays dice, as Einstein put it. The question has as much practical importance as worrying about whether real numbers are physically realized. Namely, almost none. Cryptographers would like to have some true randomness because some theorems need it. But even there, bounded computation comes to the rescue: if it would take more computing power than you’ve got to distinguish something from random, the best you can do is make random predictions.

    A chaotic system is defined as one in which if you have any error in the initial measurement, then after some time (which is a function of the initial error), you have no ability to predict where the system will be. So it’s indistinguishable from random. On the flip side, if you have good initial measurements and a good model of how the system evolves, you can predict the system for a little while.

    This claim that stochastic means iid has no redeeming qualities however.

  117. John P. Reisman (OSS Foundation):

    #113 numerobis

    It’s my personal pet peeve. If Norman wants to make ridiculous out of context claims, or anyone else for that matter, I think it would at least show integrity if they/he had enough honor to stand by their/his words by using ones full legal name.

  118. sidd:

    Mr. John. P. Reisman writes on the 30th of March, 2012 at 6:48 PM:

    “If Norman wants to make ridiculous out of context claims, or anyone else for that matter, I think it would at least show integrity if they/he had enough honor to stand by their/his words by using ones full legal name.”

    I beg to disagree. Mr. Norman might be a man of the most perfect integrity, who chooses to omit his “full legal name” for reasons of privacy. Mr. Norman might be the nom de plume of a battered spouse, for example.

    You may argue that Mr. Norman is misled, or worse, that his comments are ingenuous attempts to mislead, but the fact that he does not post his name is no reason, a priori, to weight his words one way or another.

    You may observe that i do not post with my “full legal name” either, (which is easily found), but i do hope that you will not hold that against my arguments. Our hosts here at realclimate do not require full names but you seem to be more discriminating.


    [Response: There are a multitude of reasons why people might post comments anonymously, and multiple reasons why comments might not be productive. There is only a small amount of overlap. We ask only that people do not post under multiple names particularly in the same threads. – gavin]

  119. John P. Reisman (OSS Foundation):

    #118 sidd

    I certainly do not disagree with legitimate reasons to post anonymously. I am glad that Norman Grinvalds is willing to at least stand by his words.

    And you can beg all you want in disagreement, but I doubt anyone has perfect integrity. Plus, i’ve heard the spouse abuse argument before. You extrapolate too much in support of your point.

    As I have indicated, those that have no such dangerous impediments should use their full names to at least stand by their words without being a figment of voice.

    And I have no issue with fair argument when it is based in pragmatism and relevant context. Norman Grinvalds has no such basis in the gist of his position. He has demonstrated in his visit to this thread that he uses facts out of context as the basis for his arguments.

    It may be possible that he will learn the context someday, but thus far that seems to be a point in the future. Learning requires an open mind to well founded reason. Normans grasping at out of context straws indicates that he does not have the perspective required to comprehend the science nor the implications derived form that science, even though it is essentially cause and effect when you boil it down.

  120. John P. Reisman (OSS Foundation):

    #114 Norman Grinvalds

    1. From my perspective it does not matter if you are famous. I merely consider it important that people take responsibility for their words, especially, when they seem so far departed from reality, as it indicates at least the integrity to do so. I wish more would do so.

    2. As to the PDF you linked to. I did take a look and as expected you are taking the information out of context. The paragraph you chose focuses on the text that you apparently believe supports your general perspective. But you ignored the paragraphs before and after, and the fact that the paper itself is a particularly focused study attempting to identify some interesting information.

    The study itself states:

    Experiments with high-resolution models indicate that tropical cyclones are likely to intensify in a warmer climate (Meehl et al., 2007), most importantly in terms of their winds and precipitation, though the number of storms will likely be fewer (Oouchi et al., 2006, Bengtsson et al., 2007). As suggested in Bengtsson et al., (2007) this dichotomy is likely related to the fact that water vapor increases more rapidly than precipitation in a warming climate. This then implies a weakening in the large-scale vertical mass flux (Held and Soden, 2006) thus providing less favorable conditions for the onset of tropical cyclones. However, when favorable conditions do occur they make use of the increased humidity. This may also happen for other convectively driven systems (Allen and Soden, 2007),


    “It is important to be clear what we mean by the intensity of extra-tropical storms. In many studies this is taken to be the depth of the pressure center or the magnitude of the vorticity. However, pressure may be misleading due to changes at the larger scale whilst the parameters that matter to the public are winds and precipitation; these are the focus of this work.”

    which appear before and after the paragraph yo chose to quote. Your cherry picking of course.

    The general consensus seems to be that that there will be fewer storms but larger and more intense storms when they do spin up. This is indicated in multiple studies and still seems to be the view that is holding up in the science literature. So effectively, your position is untenable based on the evidence weighed in proper context.

    I do hope that you begin to look at the globe rather than regions and and improperly considered time scales and seek deeper into the relevant context of the studies you are cherry picking from. You will learn more when you are looking at the strongest material, that which has strong support in the peer reviewed literature or has survived peer review, but only when examined in relevant context.

    You too will eventually assimilate what this means I imagine, it is only a matter of time.

  121. Craig Nazor:


    You did not address my point. The article you posted is irrelevant to the point I am making.

    The fact that a “megadrought” may or may not have happened hundreds or thousands or millions of years ago is irrelevant, unless you are willing to take into account the best scientific explanations for that megadrought and compare them to the best scientific explanations for what is going on now.

    The truth of the matter is the driest single year in Texas that has ever been measured happened in 2011 (a drought that killed between 100 million and half a billion trees over 5” in diameter, and did an estimated $7.6 billion in agricultural losses. Records go back to at least 1871, by the way, so that’s about 140 years)


    One of the largest wildfires that has ever happened in central Texas in recorded history happened in 2011 (which burned of 50 sq. miles, destroyed over 1,200 homes, decimated a beloved state park, and has further threatened an already endangered species, the Houston toad)


    The most number of days with temperatures above 100ºF ever recorded in a single year happened in 2011 (it wasn’t pleasant to take a walk at 11PM and the temperature was still around 90ºF!)


    [There are lots of other AND’s, but I am hoping you get the point, and I don’t want to bore those who already do.}

    Extreme weather events are becoming more frequent, and they are favoring warmer and dryer, but that’s not all. Twenty years ago, white-winged doves weren’t found in Austin, only farther to the south in warmer climate. Now they are the most common dove species, and they are displacing the formerly abundant mourning dove, because average temperatures are rising. Observations such as this are happening all over the planet. We have a very good scientific idea as to why all of these events are happening now (both more extreme events and an overall warming trend in averages), and some of us want to see action taken now to avoid a lot of human suffering , as well as to avoid serious destruction to human civilization. So I ask you again, what exactly is your point? It isn’t quite clear. Maybe this question will help: do you believe that anthropogenic global climate change is real and is happening now?

  122. Radge Havers:

    Oh dear. Just a reminder, trolls are not exemplars of peak mental health. Before responding it might be a good idea to ask yourself if what you’re going to say will just enable the crazy and clog the thread.

    Sometimes, if you can’t help yourself, it’s better not to respond directly but to put your points to saner members. Also, I know you’re supposed to disarm trolls by complimenting them, but telling them how good they are at what they do is probably counterproductive. No doubt Dan H. already fondly thinks of himself as The Dean of RC Contrarians.

    On the other hand:
    SA @ 109

    “Dear moderators, it seems that we already have one “pet troll” around here, whose blatantly obvious efforts to waste people’s time with repetitive BS are tolerated for reasons that elude me — that being Dan H.

    One is more than enough. “

    Intriguing. If we can only have one, perhaps a troll fight to the death. My money’s on Normie. I think he’d thrash the bejeebers out of Dan H. and leave him cowering under his moss covered little toll bridge.

    [Response: Fun as this is, can we focus on substance and not on commenters? – gavin]

  123. Norman:

    John P. Reisman (OSS Foundation) @120 and Craig Nazor @ 121

    Camburn at Skeptical Science here did provide a long term global view of extreme weather events in this document.


    Craig the reason to study the past weather extremes as best as possible is to actually determine if extreme events are getting worse and more frequent. I was looking at Chapter 3 of the IPCC report and they have evidence that heat waves have increased since 1950. This could be a signal that global warming is shifting patterns but without the best historical context to go by it might be a premature assessment. Nature could have long term cycles not understood at this time. In the link I sent about the megadroughts, consider the megaflood evidence of the Mississippi. From the link:
    “Fluvial deposits indicate that the frequency and magnitude of large floods have varied in the upper Mississippi Basin through the Holocene (Knox, 1996). For example, overbank deposits in the upper Mississippi Basin (southwestern Wisconsin, Knox, 1996, fig. 5) suggest that several extreme floods occurred between 5,000 and 6,000 radiocarbon years ago that were larger than any historical flood. In contrast, only minor floods occurred in the upper Mississippi Basin between 5,000 and about 3,000 radiocarbon years ago (Knox, 1996). These extreme floods and the long interval without major floods would have had significant impacts on flow into the Gulf of Mexico.”

    A thousand year period of extreme floods and then a 2000 year period of only minor floods.

  124. Ray Ladbury:

    Another reason to study paleoclimatic extremes is to try to ascertain what sort of behavior is possible. There is no guarantee that local climatic events from 5-6000 years ago are in any way representative of what we can expect from the current climate or indeed from what the current climate would have been absent anthropogenic warming.

    In this sense, a 1000-year period of extreme flooding in what is currently the US breadbasket is certainly an admonition that we could realize similar conditions with our current experiments with climatic alteration via greenhouse gas injection. Such an epoch would undoubtedly be a serious concern if we are to feed a world of 10+ billion people by mid-century.

    Were paleoclimate the only thing we had to go on, this prospect would remain an admonition. However, the physics also suggests increased extreme weather, so the prospect is elevated to the level of credible threat.

  125. John P. Reisman (OSS Foundation):

    #123 Norman Grinvalds

    In addition to Rays pertinent comment #124 – In this case it’s all about attribution.


    The key is what is the cause factor in different cases. As I have said in the past, the reason one person gets mad at you may not be, and in fact is likely not, the same reason another person gets mad at you years later. But to be sure, you still need to determine the reasons and cause factors. That is what climate science does in attribution analysis.

  126. Susan Anderson:

    hey guys, back to the science please. Tune out the trolls – you give them attention, like a two-year-old, they will amplify. Time them out – they can’t stand the silence.

  127. Radge Havers:

    @ 122

    -gavin. Sorry.

  128. Norman:

    Craig Nazor @121

    “So I ask you again, what exactly is your point? It isn’t quite clear. Maybe this question will help: do you believe that anthropogenic global climate change is real and is happening now?”

    Yes to your question. I do think the addition of CO2 via burning fossil fuels does cause some warming. The point is to determine if extreme weather really is increasing do to the warming or not by comparing past extreme weather events that took place without the warming to then make determinations on course of action.

    It is a matter of concren and degree. If things will get very extreme soon the human race may have to take some drastic action to curb CO2 emission. If not so extreme, the human race can gradually wean itself off of fossil fuels as other technology becomes available. You are perhaps convinced of the worst case model prediction and want drastic action at this time (even though no alternative source of energy is available to sustain the current living standards). I am not so convinced at this time.

    Basically the extreme weather of the future is the result of model runs. It is variable and usually they take a large number of models to try and get a best look at potential future climate.

    If this task would be taken on by the those who program climate models it certainly would help settle the issue. The task would be for climate models to predict major climate events accurately for the next 10 years. Where the next major global droughts will occur, how long they will last and how much area they will cover. The same with very wet areas and which major rivers will flood. Prediction of major heat waves and cold snaps. It the models could provide this predictive power I would then suggest that more drastic curbs of CO2 might be in order. In the meantime I would think what Obama is doing is a good step. Make cars more fuel efficient.

  129. Norman:

    Ray Ladbury @124 and John P. Reisman (OSS Foundation)@125

    I am slowly making it through Chapter 3 of the IPCC SREX report on extreme weather.

    I have not found the information I was looking for at this time but maybe you are familiar and can supply good links (if interested).

    My claim is that exterme weather patterns (drought, heat wave, cold snap, or flooding) are created by known phenomena and are not random fluctuations of the temperature field. The phenomena that generates these extremes is atmospheric blocking patterns. All the recent heat waves have been attributed to these blocking patterns. I asked the question on Skeptical Science and will ask it here. If AGW will increase the number and length of blocking patterns then I will completely agree that global warming will lead to more extreme weather. I have not found a study to detrmine this and I am not even sure why they form and why they persist.


    Well known blocking patterns and the weather they create.

    Evidence that both Europe of 2003 and Russia of 2010 were the result of these persistent blocking patterns. Hot in one location then on the opposite side you see much cooler (below normal temps). Just as described in the site explaining the common blocking patterns.

    Russian Heat wave (note very hot and east of heat, colder than normal)


    European heat wave of 2003 (same pattern)


    My question to either of you is what evidence do you have to prove that blocking patterns will increase in the future leading to more extreme heat waves, droughts, and floods? (Also possilbe cold, Fairbanks Alaska had five days in a row of record cold temperatures in November 2011).


  130. Chris Dudley:

    Hi Susan (#108),

    Chris Mooney and Andy Revkin both seem to think that the conservative distrust of science comes from policy disagreements first. http://www.huffingtonpost.com/chris-mooney/the-science-of-truthiness_b_1379472.html and http://dotearth.blogs.nytimes.com/2012/03/30/a-republican-meteorologist-tries-to-remove-liberal-label-from-climate-concern/

    But, that only seems to work if there is a policy issue. Teaching astronomy, I’ve run into issues where students are upset about a 4.6 billion year age of the solar system or 13.7 billion year age of the universe. No policy issue there. And, while we can read quite a bit of racism into opposition to evolution, there are no specific policy issues affecting oil companies or their ilk attached to that.

    So, I suspect that the opposition to science comes first, and then it is exploited when there happens to be a policy issue that touches the anti-science posture. And example aside from climate change might be exploitation of opposition to stem cell research in order to get more traction in attempting to control women’s reproductive rights.

    It may seem kind of chicken and egg, but, I think the opposition to science comes first and then it is exploited when there is a policy issue through dishonest dealers such as the Heartland Institute: Don’t like people in lab coats? Don’t let them tell you smoking is dangerous. What do they know….

  131. Rick Brown:

    Chris Dudley @ 128 – Your observations brought to mind the following:

    “. . . Because science rejects claims to truth based on authority and depends on the criticism of established ideas, it is the enemy of autocracy. Because scientific knowledge is tentative and provisional, it is the enemy of dogma. Because it is the most effective way of learning about the physical world, it erodes superstition, ignorance and prejudice, which have been at the root of the denial of human rights throughout history, whether through racism, chauvinism or the suppression of the rights of women.”

    The Lord Taverne QC, Letter to the journal Nature, June 11, 2009

  132. dhogaza:

    Chris Dudley:

    Chris Mooney and Andy Revkin both seem to think that the conservative distrust of science comes from policy disagreements first.

    In the case of Andy, I’d say that his proven distrust of science is based on policy disagreements first.

    Though he’s very coy about it.

    We only have to look at his dismissal of this post (the OP) for evidence, and it’s not the only evidence, by far.

    Revkin has made clear, though not intentionaly, that the science scares him, seeking him to seek “balance” by embracing RPJr and being relatively dismissive of mainstream scientists such as those who run Real Climate.

  133. Craig Nazor:


    You still have not addressed my point.

    Trying to understand a change in the temperature (energy) of the climate system without understanding the state of the climate system at the time of the temperature measurement and without understanding the cause(s) of the temperature change is not likely to reveal much useful information about the way the climate system will respond in the future.

    In this case, there is a lot we know about the current state of the climate system, and there is a lot we know about the cause(s) of the temperature change we are currently observing in the climate system. You do not seem willing to discuss any of that. If you were, then you would not mind answering my question:

    Do you believe that anthropogenic global climate change is real and is happening now?

    Likewise, a discussion of extreme climate events without understanding the state of the climate system at the time of those events and without an understanding the cause(s) of those extreme events is not likely to reveal much information about the magnitude of climate events in the future.

  134. wili:

    I see we are back to tail chasing. At least it’s a new tail.

    In a (doubtless vain) effort to get us back to substantive discussion, I’m wondering if anyone has seen this and what they think:


    “2C warming target ‘out of reach’ – ex UN climate chief”

    “The UN’s former climate chief on Tuesday said the global warming pledge he helped set at the Copenhagen Summit little more than two years ago was already unattainable.

    “I think two degrees is out of reach,” Yvo de Boer, former executive secretary of the UN’s Framework Convention on Climate Change (UNFCCC), said on the sidelines of a conference here on June’s Rio+20 summit.

    The UNFCCC’s 195 parties have pledged to limit the rise in global average temperatures to two degrees Celsius (3.6 degrees Fahrenheit).

    The target was set by a core group of countries in the final stormy hours at the Copenhagen Summit in December 2009 and became enshrined by the forum at Cancun, Mexico a year later.

    But more and more scientists are warning that the objective is slipping away without radical, early cuts in greenhouse-gas emissions. “

  135. Norman:

    Craig Nazor @133

    “Do you believe that anthropogenic global climate change is real and is happening now?

    Likewise, a discussion of extreme climate events without understanding the state of the climate system at the time of those events and without an understanding the cause(s) of those extreme events is not likely to reveal much information about the magnitude of climate events in the future.”

    I did answer your question with a yes in post @128.

    I also address you point about extreme climate events in my post @129 where the topic is blocking patterns and their known effect on extreme weather conditions.

    So far I have not seen the topic of blocking patterns discussed in the IPCC SREX report. Primarily the studies use computer models for both analysis and reanalysis. These models may be spot on. But to verify their ability to accurately predict the future they should be tested so I still stand by the challenge in post @128. If the models can accurately determine extreme climate events in the near future (floods, droughts, heat waves, cold snaps…area affected, duration, and intensity) it would give the conclusions of IPCC report much weight in the Public dicourse.

  136. Norman:

    Craig Nazor,

    I am doing research. Using the NOAA data I did compile numbers of billion dollar disasters from 19810 to current. The number is indeed going up but not at the rate of inflation. Inflation is rising faster than the disaster rate trend line. Does this mean extreme weather is getting less extreme or less damaging? I tried to link you to my skydrive excel sheet on this but that site is flagged as SPAM.

  137. flxible:

    What the heck does inflation have to do with weather events?? And are events that only do 3/4 billion dollar damage not extreme events? Sounds like Norman is proposing the U.S. dollar theory of climate, that should have “weight in the Public dicourse” [sic]. Maybe he shouldn’t be posting on April 1st.

  138. dhogaza:


    Does this mean extreme weather is getting less extreme or less damaging?

    No, it means government regulation (in the form of building codes) works.

  139. wili:

    Has anyone seen this article from the _Atlantic_?


    It is mostly old news to most here about the issue of wet-bulb temperatures possibly exceeding human’s ability to survive them. I would like some response to some of the other claims in the article, though:

    “By 2100, Huber points out, the mid-range estimates predict a rise of 3°C to 4°C in average global temperatures based on current economic activities, but those studies ignore accelerating factors like the release of vast quantities of methane — a potent greenhouse gas — now trapped beneath permafrost and sea ice that’s becoming less and less permanent. Other models foresee rises in the 10°C range this century; at the outer fringe, predictions range as high as 20°C.”

    Who might he be thinking of that has predicted a 20 degree C (or even 10) rise before the end of the century?

  140. Chris Dudley:

    Rick #131,

    I suppose that racism could be the beginning of opposition to evolution and I am mistaking the policy first vrs. anti-science first order there because the civil war and civil rights struggle are largely history. Opposition to evolution would then be a vestigial aspect of a policy defeat.

    The new thesis might look like this:

    Racist predilections –> opposition to evolution –> policy defeat (civil rights) –> more general opposition to science based on sour grapes (seen in flat earth/anti-geology positions) –> successful exploitation by tobacco companies (anti-medicine) –> reprise by oil companies (anti-climate science).

    Seems more complicated, but it does fix an anti-science attitude in bitterness which would help to explain why it can take root and grow in the more educated conservatives. An unacknowledged and shameful basis like racism makes educating an anti-science position out of a conservative something that a classroom might not be able to handle. You might need to start with a therapist.

  141. Hank Roberts:

    Wili, reading the article you link, I can’t tell if that is actually quoting Huber about the “fringe” or if it’s something the author got elsewhere and tacked onto the more familiar range that Huber described.

    You might ask the guy who wrote it: http://motherjones.com/authors/michael-mechanic — with luck he’s kept notes and remembers where he got it.

    Asking your fellow readers here to guess is just, you know, reverse citation, fraught with problems because “You can find anything on the Internet!”

    So, what the heck, let’s try:

    The only place I found “10C” was in a Scholar search result:
    Long-term ecological records and their relevance to climate change predictions for a warmer world
    KJ Willis — Annual Review of Ecology, 2011 – annualreviews.org
    … Similar to current and predicted future climate change, the greatest warming appears to have occurred in the high latitudes, as mean annual temperatures were more than 10°C higher than present (Salzmann et al. 2009).

    The Willis paper at annualreviews is paywalled and that phrase isn’t in the abstract so all I have is Google Scholar’s quote without any context — but not it says “high latitudes” and that’s consistent with polar amplification, so it wouldn’t be a worldwide average number from the paleo record.

    If you search for “Salzmann et al.” you’ll find newer work by Salzmann as well — so you could do some digging. Joe Romm has had lists of extreme case numbers for a while, I’m sure you can find those.

    “fringe” may well mean “not from a science source”

  142. John P. Reisman (OSS Foundation):

    #136 Norman Grinvalds

    I think the billion dollar events are inflation adjusted but you can look it up.

    Also, re your #135, it’s about trends and attribution really. Not needed to wait until everyone is suffering higher costs to see the relationship. The published work already supports the attribution with statistical significance.

    In other words, you can ignore it all you want, but that won’t change the trend or the attribution… though the attribution will continue to achieve higher confidence intervals as time passes and the physics and understanding of the impacts of short term natural variation are better understood… along with a slew of other factors.

    Re. your #128 You are ignoring a tremendous amount of relevant factors in your narrowly scoped assessment of what to consider. Ever heard of thermal limits on crop growth?

  143. grypo:

    It’s been in the news a bit, so I’m sure it gets discussed, but I haven’t heard much reaction from the climate extreme attribution point of view about the Francis paper, that hypothesizes that the unusual blocking patterns in the NH could be the result of Rossby wave motion, as a result of Arctic sea ice loss.

    I would consider this a rather significant finding, if true, considering the lows in sea ice expected over the next decade, as well as, of course, the continuing temperature trend in the NH.

  144. Susan Anderson:

    Chris Dudley @~102:

    Thanks, but I would not put Chris Mooney in the same category. He does seem to be working his way through some issues, but if you go, as I did, from Republican War on Science to Storm World to the last two, there is a progression, as there is on what of his blog activity I’ve seen. Having satisfied himself (and many others, for which I am very thankful) as to the facts, it seems to me he is now trying to find a way to improve the situation. I do think he went through a phase of being persuaded by the “own goal” pushers, and that’s a particularly nasty one because those who question themselves are likely to get bitten. The recent brain stuff is very polarizing. On the whole, I prefer graphic information and humor as communication tools and prefer to think that most people are conflicted but basically mean well, though it’s easy to wonder these days.

    Andy Revkin’s science deficit is strange and I wish it were possible for some of you who know what you are talking about to help him with it, but I guess his preeminence in the field for so many years has become a liability to opening the mind in that area. His embrace of Pielke and anyone else he can find, most recently Wallace is sad and unhelpful. He does get a lot of help there from his fan club on DotEarth. I have an even more limited education, which makes me think it’s not about getting more training but something else. I’d best leave it at that for now.

  145. Xiedaoan:

    The excerpt from Willis and MacDonald 2011 refers to mid-pliocene. If an extensive quote is desired here, I could provide that. Or if we can arrange to ‘meet outside’, I can email the entire article.

    It is a good one, reviewing the migratory abilities of plants & animals. Temperature extremes are not really the focus – more like rates.

  146. John Pollack:

    Norman @129 I generally agree with part of your claim: weather extremes tend to be produced by known phenomena. (But watch out for the ones that represent new weather patterns for the area concerned!) However, this is far from allowing them all to be attributed to blocking. Of course, prolonged heat waves and cold spells result from blocking, but the tendency over time is for the mid latitude heat waves to get hotter, and the cold spells, less so. For example, the blocking weather pattern that produced the central U.S. heat wave last summer was very similar to the 1980 pattern, but hotter overall. North of the dry line (located last year mostly in KS, same as 1980) high temperatures set few if any records, but lows and dew points were both warmer than 1980, and in record territory, an AGW footprint.

    Furthermore, a lot of extreme events result from closed lows. Check out pg. 304-6 of March Bull. of the Amer. Met. Society if you aren’t paywalled. Nguyen and DeGaetano find that the frequency of closed upper lows in the northeast U.S., and the precip. in the vicinity of each low, have shown statistically significant increases in the past 60 years. “This trend of rainier storms is consistent with increases in tropospheric water vapor due to increased global mean temperature.”

  147. Jim Larsen:


    You are correct that known and unknown phenomena cause individual weather extremes, and each second, minute, day, and month affects the next. But isn’t that trivial?

    You’re also correct that times and areas of heatwaves are balanced by times and areas of cool weather, but since 2000, 47 countries have new record highs while 8 have new record lows. Reality seems to follow the OP’s contention.

    You might be correct that a narrowing of the thermal differentials between day and night and summer and winter could reduce some forms of extremes (I’m thinking extratropical cyclones), but it could just move them poleward. Then there’s the fewer, more powerful hurricanes hypothesis.

    But the topic is “Extremely Hot”, and it is pretty cut and dry. Move or warp the curve and the probabilities at the tails are affected more than in the middle. Sort of the polar amplification of statistics.

    What was the guy from Skeptical Science talking about? Long discussions about ….


  148. Norman:

    John Pollack @146

    I am in agreement that AGW will increase the temp of heat waves when they take place. Omaha, Nebraska reported its hottest March since records begin. But it was only about 1.5 F above the previous record that took place in 1910. Perhaps the patterns were familiar in both cases. The AGW signal is the warmer overall temp. To get similar conditions in the area of Omaha, Nebraska (not just a point source, the warmth was extensive across the US) took 100 years from 1910.

    The point I am making is that nearly all of the extreme weather events are casused by blocking events or cut-off lows. I have not yet found the forces that create and sustain these blocking events. They are well known and observed. Do your sources have the explanation of what causes the blocking patterns and what determines their sustainabliltiy?

    My point is that you have 3 possibilites with AGW. More blocking patterns develop and last longer. In this case extreme events would definately increase in number, intesity and duration. You could have the same number. Then you will have heat waves with a little higher overall temps than previous as Omaha has experienced. If AGW causes fewer blocking patterns that are of shorter duration, then I would expect less extreme weather events in the future. The ones that do happen would be warmer than previous or wetter but there would be fewer overall and if they do not last as long, even the high temperatures may not exceed previous levels.

    This is the major point I am making in my posts. If you have the answers please share. Thanks.

  149. grypo:

    “This is the major point I am making in my posts. If you have the answers please share. Thanks.”

    See my #143

    See also papers within this Masters post.

    See also this Francis post.

  150. Chris Dudley:

    Susan #144,

    It looks like Mooney is also looking at a psychological explanation of why conservatives distrust science. http://www.salon.com/2012/04/02/inside_the_republican_brain/singleton/

    He also mentions Nixon’s southern strategy which worked because Kennedy and LBJ passed civil rights legislation. Perhaps the way to talk the conservatives out of their position is to discuss how the Church of Ethiopia was one of the first established, and any implication in the theory of evolution that all men are brothers was established long before when St. Phillip baptized the Ethiopian. No need to hate evolution on that account.

  151. Matt:

    The attribution of extreme weather events to AGW seems an important topic to me. If it was possible to say that a particularly severe heatwave or other extreme weather events was probably caused by AGW, this might help might make AGW a more “real” and personal problem to those who experienced the weather event.

    So I’m interested in the possibility of frameworks for calculating the probability that AGW “caused” a particular weather event. I.e. the probability that global warming due to anthropogenic activities was a *necessary* (if not sufficient) condition for a particular weather event to occur.

    Say that climate models indicate a particular weather event W(say a heatwave of a particular extremity) has a probability P(W|AGW’) of occurring in a certain time period in the absence of anthropogenic forcings. The models also indicate that the event has a probability P(W|AGW) of occurring in the chosen time period *with* anthropogenic forcings included.

    Then it seems to me that the probability that the event was “caused” by AGW is:

    [P(W|AGW) – P(W|AGW’)] / P(W|AGW)

    i.e. This is the probability that the event would NOT have taken place in the absence of AGW, or in other words the probability that AGW was a *necessary* condition for this particular event to occur. Does this make sense, or am I missing some important issues?

  152. Jim Larsen:

    148 Norman said, “My point is that you have 3 possibilites with AGW. More blocking patterns”

    Great question. Let’s ask Mother Nature.

    I pointed you to a list showing 47 countries with record highs and 8 with record lows in this century. This entire period was one of flattish temperatures. Had temperatures risen as they were “supposed” to, surely the ratio would have been even more lopsided. Additionally, the largest countries are in the arctic, and so are underrepresented in the data. Since they’ve been warming the most, the results could be biased low.

    Infinitely more rigourous, but still incredibly readable is Hansen’s paper. Figures 7 and 9 are very informative.


  153. Norman:

    grypo @149

    Interesting links. Thanks. My observation of the Francis paper. Meteorologist should be able to determine if storm systems are moving slower today than they had been 30 years ago. I did find this The predictablilty of atmospheric blocking. This article gives many theories on how blocks form. By reading through some of them I am trying to determine if the paper you linked is correct reasoning based upon what is already known about blocks.

    I do have some question about your link about Arctic Amplification being a cause for the heavy snows in the US and Europe a few years back.


    Moving through the snow cover anomaly graphs, I can’t see any clear evidence that would suggest Arctic Amplification is responsible for more snow in early winter. In December on the graphs, the only thing that stands out as unusual is a few years of really low snow cover. The rest looks fairly normal. I do not know if there is enough evidence to support the conclusion (certainly does not seem overwhelming).

  154. Norman:

    John P. Reisman (OSS Foundation) @142

    “Re. your #128 You are ignoring a tremendous amount of relevant factors in your narrowly scoped assessment of what to consider. Ever heard of thermal limits on crop growth”

    Thanks for leading me in this direction. I have been reading this article on the topic. It seems heat can be very bad for some crops. I live in corn country and it seems to do well as long as there is some rain. I also garden in the summer and have not noticed a loss of vegetables from having a hot summer. As long as I water regularly during a dry spell I have had good production for years.


  155. Jim Larsen:

    151 Matt asks, “.e. This is the probability that the event would NOT have taken place in the absence of AGW, or in other words the probability that AGW was a *necessary* condition for this particular event to occur. ”


    Go to the leftmost graph in Fig 9. It shows distribution curves for each decade’s temperatures. Compare the 1950s and 2000s curves to the OP’s hypothetical pair in the unlabeled(!) graph depicting a one SD warming. There’s a similar increase, but the real curves show a huge increase in variability, with record lows remaining pretty constant at -3 SD, but record highs stretch from 3 to 5 SD! This has resulted in a massive increase in extreme highs worldwide. The OP’s black dotted line ends at 80 to 1, but it’s safe to say we’re getting over 100 times as many 5 SD heat events than we did in the 1950s.

    Or, in Fig 2, 3 SD events are graphed as “extremely hot”. They were a few tenths of a percent by area up until 1980. Now they’re 10% of the globe.

    Hansen says, “The increased frequency of these extreme anomalies, by more than an order of magnitude, implies that we can say with a high degree of confidence that events such as the extreme summer heat in the Moscow region in 2010 and Texas in 2011 were a consequence of global warming. “

  156. Hank Roberts:

    “Reproductive development of many crop species is damaged by heat such that they produce no flowers or if they produce flowers they may set no fruit or seeds. The reviews of Hall (1992, 1993) discuss the detrimental effects of heat stress on reproductive development that has been reported for cowpea, common bean, tomato, cotton, rice, wheat, maize and sorghum. …”

  157. Dan H.:

    One needs to be careful when comparing the s.d. between 1950 and now. Hansen admits that “the small variability must be an artifact of limited measurements during 1951-1980.” The curves in Fig. 9 change depending on the base period used.

    Hansen chose his base period for most figures as 1951-1980. Is it any wonder that a greater number of higher sigma events occurred during the recent warmer years, than the previous, cooler ones. Since Hansen states that temperatures during this interval increased by one s.d., the occurrance of 2-sigma warming events today, would equal those of 1-sigma events 50 years ago, and the reverse for cold events.

    If it can be shown that global warming is responsible for the recent blocking events, then he would have a much stronger case for his asertions. This also applies to the recent blokcing this winter in the U.S. and Europe. Both the U.S. and Russia experienced a similar blocking events in the 1930s. Most of the U.S. record summer highs were set then, while in Russia, they were set last year. I am also curious how someone can “imply” something with a high degree of confidence.

  158. Hank Roberts:


  159. Hank Roberts:

    > Is it any wonder that a greater number of higher sigma events
    > occurred during the recent warmer years, than the previous, cooler ones.

    Conflating the average with the variability?

  160. Jim Larsen:

    157 Dan H said, “temperatures during this interval increased by one s.d., the occurrance of 2-sigma warming events today, would equal those of 1-sigma events 50 years ago, and the reverse for cold events.

    If it can be shown that global warming is responsible for the recent blocking events, then he would have a much stronger case for his asertions. ”

    Temps went up one SD, but the distribution widened from 6 SD to 8 SD. Hansen used half of the data for the base period and gave excellent reasons for his choice, primarily centered on that this technique reveals the moving trend the best. You, (surprise!) feel it is the worst technique because it reveals the moving trend the best. If you’re actually concerned about the length of the base period, perhaps you could widen it by adding in years prior to 1951.

    While you’ve been away, we’ve been linking and discussing papers and articles about the causes for the recent increase in blocking patterns. Essentially, lower equator to pole temperature differential –> slower jet stream –> blockages and sluggishness in jet stream variations.

    i.e. the jet stream whips around more the faster it goes.

    Arctic amplification will only increase, so I think this one goes on the “It’s worse than we thought” shelf. Do you agree, Dan?

  161. Hank Roberts:

    “… researchers led by Sirpa Häkkinen, an oceanographer at NASA’s Goddard Space Flight Center in Greenbelt, Md., analyzed atmospheric data from the 20th century and found a correlation between periods of warmer-than-usual waters in the North Atlantic, and a higher frequency of blocking events….
    … Clusters of blocking events can divert the normal track of hurricanes … In some cases, this change can speed up or slow down large, circulating currents in the ocean known as gyres ….

    Slower, weaker gyres allow warm waters to escape farther north.

    ‘These warmer and more saline waters then invade the sub-polar ocean and cause a series of impacts,’ Peter Rhines, an oceanographer at the University of Washington, Seattle, and co-author of the new study, said ….”


    for 2009
    Richter-Menge, J., and J.E. Overland, Eds., 2009: Arctic Report Card 2009,

    “It is apparent that the heating of the ocean in areas of extreme summer sea ice loss is directly
    impacting surface air temperatures over the Arctic Ocean, where surface air temperature
    anomalies reached an unprecedented +4°C during October through December 2008…..

    … There is evidence that, by creating a new major surface heat source, the recent extreme loss of
    summer sea ice extent is having a direct feedback effect on the general atmospheric circulation
    into the winter season (Francis et al., 2009)…. the effect of higher air temperatures in the lower Arctic atmosphere is contributing to changes in the atmospheric circulation in both the Arctic and northern mid-latitudes. For example, Honda et al. (2009) suggest a remote connection between loss of Arctic sea ice and colder temperatures over eastern Asia….”

    Current page:

    “What’s new in 2011?

    Persistent warming has caused dramatic changes in the Arctic Ocean and the ecosystem it supports.

    Ocean changes include reduced sea ice and freshening of the upper ocean, and impacts such as increased biological productivity at the base of the food chain and loss of habit for walrus and polar bears.

    Atmosphere Significant change
    Higher temperatures in the Arctic and unusually lower temperatures in some low latitude regions are linked to global shifts in atmospheric wind patterns….”

  162. Dan:

    Link to the Francis/Vavrus abstract:
    Evidence linking Arctic amplification to extreme weather in mid-latitudes

    “Arctic amplification (AA) – the observed enhanced warming in high northern latitudes relative to the northern hemisphere – is evident in lower-tropospheric temperatures and in 1000-to-500 hPa thicknesses. Daily fields of 500 hPa heights from the National Centers for Environmental Prediction Reanalysis are analyzed over N. America and the N. Atlantic to assess changes in north-south (Rossby) wave characteristics associated with AA and the relaxation of poleward thickness gradients. Two effects are identified that each contribute to a slower eastward progression of Rossby waves in the upper-level flow: 1) weakened zonal winds, and 2) increased wave amplitude. These effects are particularly evident in autumn and winter consistent with sea-ice loss, but are also apparent in summer, possibly related to earlier snow melt on high-latitude land. Slower progression of upper-level waves would cause associated weather patterns in mid-latitudes to be more persistent, which may lead to an increased probability of extreme weather events that result from prolonged conditions, such as drought, flooding, cold spells, and heat waves.”

  163. adelady:

    Matt@ 151 “the probability that global warming due to anthropogenic activities was a *necessary* (if not sufficient) condition for a particular weather event to occur.”

    Recently I’ve begun to think that the necessary/sufficient distinction could be very useful even in non-technical statements for general public consumption. Most people have come across the necessary v. sufficient concept before. Those who fancy themselves as well versed in technical matters even more so.

    Saying that warming has given us a constant ‘necessary’ condition for extreme events sets things up for both expected (say during El Nino events) and unexpected outcomes (WACCy weather being one). When other variables come into play in certain places and conditions, we can get ‘sufficient’ factors for an unusual flood, an extended heatwave or an exceptional drought.

    (And the argument also works quite neatly in reverse – but I think the way I’ve expressed it is the correct one, as well as being more persuasive. I’ve got a biological parallel/analogy in mind that has the same characteristics, but the words won’t come together neatly. I’ll leave it for later.)

  164. John Pollack:

    Norman @ 148 No, I do not have sources that would allow me to state the trend for blocking events under future AGW. However, I don’t see why there has to be one trend. It could well be location dependent, sensitive to changes in SSTs, etc.

    Meanwhile, the observed empirical trend is toward greater extremes of precip. and warm events, but not cold events. That’s just what we expect of AGW in general. BTW, the Omaha March mean temp. record set in 1910 was the most extreme of any monthly anomaly, except perhaps the cold Dec. 1983, and has now been exceeded by 1.8F. Furthermore, the 1910 warm March was followed by a hard freeze in April. There is a decent chance that won’t happen this year, as there isn’t even much of a cold pool in Canada. Time will tell.

  165. Norman:

    John Pollack @164

    The long term forecast for Omaha in April is cooler temperatures (at least much closer to the normal for this time of year).

    I did find this link to global and US climate patterns (heat waves, preciptiation etc.).

    Except for overall warming and night time warming my visual accuity is not fine enough to see a trend to the extreme.


    US heat wave index does not seem to be rising. Amount of US area with above normal highs is rising but nothing special in the historical context.

    US drought index for the last 10 years is static (some years worse than others).

    Now for Global effects, the graph of global precipitation does not show this frightening increase above the historical norm.

    Abnormally high annual rainfall in the US is creeping up in area affected but not at an alarming rate with respect to the historical average, it is a very dynamic nature that varies alot on a yearly basis.

    North Atlantic cyclone intensity is a flatline since 1950.

    I will keep an open mind that my observations of this data are not correct but I will let you view it yourself to form your own conclusions.

  166. Dan H.:

    I do not disagree with that explanation for the increase in recent blocking events, and there is sufficient evidence for an increase in the past 50 years. However, similar conditions are thought to have contributed to the increase in blocking events presumed to have occurred in the 1930s.

    My issue was not in adding years prior to his data set, but rather that the choice in base period affected his results. It is not surprising that a greater s.d. occurs, when the base period differs from the dataset. In Hansen’s Fig. 9, the s.d. is less when the current decade is plotted against the base period in which the temperatures occurred. When using the entire base period, 1951-2011, he s.d are similar for all decades, just shifted higher. This is exemplified in his Fig. 2.

  167. Steven Franzen:


    How are you coming along with reading SREX report Chapter 3? A point you were previously capitalising on is blocking patterns:

    So far I have not seen the topic of blocking patterns discussed in the IPCC SREX report.

    My claim is that exterme weather patterns (drought, heat wave, cold snap, or flooding) are created by known phenomena and are not random fluctuations of the temperature field. The phenomena that generates these extremes is atmospheric blocking patterns. All the recent heat waves have been attributed to these blocking patterns.

    If AGW will increase the number and length of blocking patterns then I will completely agree that global warming will lead to more extreme weather.

    So, what if it can’t be found that AGW increases the number and length of blocking patterns, or if extreme weather is not solely caused by atmospheric blocking? Would that make you “incompletely agree” or completely reject the statement that global warming will lead to more extreme weather?
    Because the SREX report does mention some issues you seem to have in Chapter 3, page 130:

    Some processes –
    particularly those involving feedbacks (Section 3.1.4), and this is
    especially the case for climate extremes and associated impacts – are
    still poorly represented and/or understood (e.g., land-atmosphere
    interactions, ocean-atmosphere interactions, stratospheric processes,
    blocking dynamics) despite some improvements in the simulations of
    others (see Box 3-2 and below). Therefore, limitations in computing
    power and in the scientific understanding of some physical processes
    currently restrict further global and regional climate model improvements.

  168. wili:

    Thanks hank and Xiedaoan. I just wondered if there was some well-known major scientist who has been talking about heating in the range of 10-20 degrees that anyone knows about but I somehow missed. It sounds like there is not.

  169. wili:

    OK, I approached it from the other direction. I thought about which prominent scientists say the most grim things about the likely future in regard to GW and James Lovelock came to mind. I did find a number of blogs that seem to be quoting him sometime in the mid aughts as saying that global temperatures could rise ten degrees in the next decade. Of course, they did not give the source, but it sounds like it might have been something in his “Revenge of Gaia.” If someone has that on hand or can give me a better source, I would appreciate it.

  170. wili:

    Sorry for the back-to-back posts, but I tracked it down to a Washington Post article:


    “The nature of Earth’s biosphere is that, under pressure from industrialization, it resists such heating, and then it resists some more.

    Then, he says, it adjusts.

    Within the next decade or two, Lovelock forecasts, Gaia will hike her thermostat by at least 10 degrees. Earth, he predicts, will be hotter than at any time since the Eocene Age 55 million years ago, when crocodiles swam in the Arctic Ocean.”

    From “The End of Eden” by Michael Powell Sept. 2, 2006.

    So we are now only four years from when we should have a ten degree hotter temperature, according to Lovelock in this article, at least going by his closest extimate. Things will have to heat up pretty fast if this is to come true.

    I do think his point about complex systems’ propensity to go through sudden, rapid change is important to keep in mind.

  171. Hank Roberts:

    > Norman says: …
    > view it yourself to form your own conclusions.

    See, this is the reason you’re having problems with science.

    Humans excel at finding patterns, whether there’s reality there or not.
    This served you well; you are descended from a long line of primates with sufficient skill to _always_ detect the leopard lurking in the shadows and escape up a tree. The cost of mistakenly imagining a leopard was trivial; the cost of mistakenly not detecting a leopard was a notable lack of grandchildren.

    You don’t need to believe in evolution; all you need to understand is that for whatever reason, you are typically human and excel at seeing patterns — whether or not there’s a pattern in the actual reality.

    Your eyes aren’t reliable.

    This is why statistics has been invented — to correct our lying eyes.

  172. Andy:

    I read Wallace’s opinion piece and it makes perfect sense to me. He’s simply stating that we need to take a longer and broader look at the negative affects of global warming and to not ignore the other dire environmental degradation occurring on our planet.

    I think a good lesson is what was learned from the discussion surrounding the “Population Bomb”. Most of the dire consequences of our high population growth are now unfolding; but since the predictions weren’t evident shortly after its publication they were viewed by the public as being incorrect. Didn’t matter that the authors stated it would be decades for the effects to become evident; some environmentalists screamed that the end was nigh and when that didn’t happen the book’s warnings were tossed in the trash heap and now we’ve got 7 billion and counting and we’re still debating use of birth control.

    So it will be with global warming’s worst effects which are still many decades out. By the time they are evident to the general population, beyond our weather’s not infrequent extremes, it will be too late. Use these events as teachable moments. A portend of what’s to come. Otherwise we simply build a better tornado warning system, hurricane proof homes, more dams and the problem’s solved right? Then in 80 years time we wake up and half of this earth’s organisms are gone, it’s always too hot to work in the yard on Saturday, the kids don’t know why anyone would ever want to play outside or go camping like in the “olden” days and we’re taking underwater tours of Louisiana. Bad weather is going to be the least of our problems.

    And it does no good to be able to say “I told you so”.

    Therefore, Wallace is saying let’s use a different strategy. I agree. Otherwise it’ll be heads we lose, tails they win.

  173. Brian Dodge:

    “US heat wave index does not seem to be rising.” Norman — 3 Apr 2012 @ 11:21 PM

    My sources disagree –

    “Like the heat wave index, the percentage of the United States affected by heat waves has also risen steadily since the 1970s (see figures 2 & 3). The recent period of increasing heat is distinguished by a rise in extremely high nighttime temperatures.” epa.gov/climatechange/indicators/pdfs/CI-weather-and-climate.pdf (a disproportionate rise in night vs day temperatures is a signature of AGW.)

    What’s your source that the heat index “seems” not to be rising?

  174. Dan H.:

    Based on the link to the epa heat wave index, the value has risen since the relatively cool 1970s, but is still much lower than the 1930s. So I would say that both your statements about the heat index are correct; they just need to be put in the proper timeframe. Short-term – yes, long-term – no. The same can be said of daily high temperatures, higher than the 1970s, but not the 30s (although much closer than the heat index). The higher nighttime lows is dramatically higher recently.

  175. sidd:

    Mr. Norman writes on the 3rd of April 2012, at 11:21 PM:

    “…global precipitation does not show this frightening increase above the historical norm.”

    Global precipitation is interesting. The mode is moving down, while the extremes are kicking up. The following plot is a histogram of deviation from local average vs local standard deviation on a 2.5 degree grid, lumping the events at larger than 5 sigma.



  176. sidd:

    i should say that the data fro the graphs i posted are monthly, and here is the same data on a log scale


    which show the increase in hi sigma events


  177. Norman:

    Hank Roberts @170

    “This is why statistics has been invented — to correct our lying eyes.”

    This would be great if statistics were always used correctly and with good intent but people are what they are. Not only are humans excellent at pattern recognition but they also seem to have an ability to decieve. Statistics can mislead, they are as valuable as the person who is using this tool. Science is the same way, an excellent tool when used correctly, but humans are still what they are. That is why one must always question all and the truth will come out. My questions do not mean my view is correct, but they are necessary for science to remain the useful tool it was designed to be.

    Remember the saying “There are three kinds of lies: lies, damned lies, and statistics.”

  178. Norman:

    Brian Dodge @172

    I would agree that the heat index rose from 1970 to current. Just from 2000 to current it does not appear to be rising and it is no where near the level of the 1930’s. In the historical context it does not appear to be rising and it does not show a pattern of a rapid increase at this time.

    That is why I posted the link with my observations. Here is my claim “I will keep an open mind that my observations of this data are not correct”

    So I thank you for considering them and responding. It keeps the most important aspect of any science alive, thinking.

    One of the reasons I post on extreme weather threads is it seems too many just accept what is said without thinking about it or investigating the claims on their own. Doing some research.

    There is a claim global droughts are increasing. In this paper it shows that globally droughts are not showing any sign of increasing from 1950 to 2000 (page 444 of this article has a series of graphs, the first is global then many regional graphs). Some regions have increasing droughts, others have decreasing. Globally there is no apparent change.


    “Concurrent changes in drought spatial extent are
    evident, with a global decreasing trend of 0.021% to
    0.035% yr1.” From the summary of the above linked report.

  179. Norman:

    Brian Dodge @172

    From this source I would certainly agree that extent of very warm area has increased from 1983. But it also looks like is is going down a bit.


    Each month’s extent of very warm area is given in the bar below the graph. If you are interested I can put the data in an excel sheet and determine the trend line. It is time consuming and only would do this if you think the task of value.

  180. Hank Roberts:

    That 2006 quote says “set the thermostat” — so

    Assume he meant what he says.

    The next two decades are 2010-20 and 2020-30, if you’re counting by tens.

    Change the thermostat by ten degrees sometime in there — whatever that means for Lovelock — and it’d still take a long time to show up as a higher than expected increase in warming.

    Sure, you can imagine awful stuff. How about an outbreak of some unknown microorganism that trickles down with the rainwater and causes the Antarctic ice cap to slip loose and fall apart? Or something that lives in the top layer of the ocean and produces lots of hitherto unknown chlorinated greenhouse gases metabolized by consuming all our floating plastic scrap.

    But those are monster-under-the-bed notions, Gaia being the monster.
    The Medea hypothesis is quite sufficient for me.

  181. Norman:

    Steven Franzen @166

    “So, what if it can’t be found that AGW increases the number and length of blocking patterns, or if extreme weather is not solely caused by atmospheric blocking? Would that make you “incompletely agree” or completely reject the statement that global warming will lead to more extreme weather?”

    No, I am not an absolutist. I like evidence based science the best when possible. You have a theory why weather would get more extreme. The current theory is warmer atmosphere has more energy and more water evaporation should lead to more intense storms and warmer temps should lead to more severe droughts. These are possibilites but they may not take place as expected. One is the Arctic Amplification may lessen storms, since the arctic is warming faster than the poles the potential energy is reduced. Even though the overall atmpospheric energy has increased, it is not total energy that drives a system but differences in energy between two regions.

    The only one that I can really conclude from global warming is that average precipitaion will increase (what goes up must come down, equilibrium) and that average temperatures will increase. That more extremes will develop is only a theory at this time and I am still looking for solid evidence to suggest it is more than such. It might be out there, I just have not found an really convincing amount of evidence.

  182. sidd:

    Grr, I cannot type. Let me begin again. The data are for monthly precipitation on a 2.5 degree grid from


    I calculate the deviation for local average divided by local standard deviation for each grid point. Then i plot the histogram, lumping the counts for events greater than 5 sigma from the local mean.

    The results are at


    the latter on a semilog scale to better show the increase at large sigma.


  183. Tokodave:

    Norman @ 179 “That more extremes will develop is only a theory at this time…” There are a number of metrics that suggest more extremes have developed; the number of FEMA declared disasters, increase in the amount of rain falling as “very heavy precipitation”, insured losses related to weather, significant weather related U.S. electric grid disturbances, relative number of high temperature records compared to cold temperature records, and of course the record number of billion dollar extreme weather events in 2011. Some of these have a cultural component, for example what FEMA declares a disaster, but collectively these suggest we are in fact seeing the very extremes you’re looking for.

  184. Thomas Lee Elifritz:

    There is a claim global droughts are increasing.

    What ‘global droughts’ are you referring to Dr. Norman Page, petroleum geologist and frequent WUWT commentator?

  185. Hank Roberts:

    Norman, have you taken a statistics class?

  186. Dan H.:

    Unfortunately, people use those statistics which support their viewpoint, and ignore those that do not. The same can be said for data. I am always suspect when someone uses only part of the data, or analyzes the data in an unusual way.

  187. John P. Reisman (OSS Foundation):

    #177 Norman Grinvalds

    The problem is clear, you’re not using science correctly in your analysis, you’re using your own bias confirmation.

    That’s not scientific at all. Examine the confidence intervals re status of current understanding and underlying foundations that have survived peer response and maybe those cataracts will get better.

  188. John P. Reisman (OSS Foundation):

    #186 Dan H.

    Are you saying you have never made a claim inferring that there is no warming in the recent trends, or anything similar to that effect in relation to climate science?

  189. Dan H.:

    Your words, not mine. I have stated repeatedly that we should be looking at the long term, not short term shifts. Looking at the warming or cooling over the short term is only important in attempting to correlate these changes with other forces.

  190. Norman:

    Tokodave @183

    I am looking into the billion dollar disasters here.

    The Texas drought/heat wave of 2011 was listed as a $10 billion disaster.

    Scroll down on the link I provided and you see in 1988 the heatwave/drought was a $40 billion (adjusted to 2007 dollars I believe) that killed 5000 to 10000 people. Then in 1980 you have another heat wave and drought that was a $20 billion disaster that killed 10000 people. So in a historical context it is not so clear that heat waves and droughts are actually getting worse in time. You can look through other disasters as well.

    Seven of the 14 billion dollar disasters were casued by tornadoes. It was just a freak year for tornadoes and many hit cities. If an F4 or F5 hits a major city you are almsost assured it will cause a billion dollars worth of damage.

    Here is another possibility that can explain an increase in weather related disasters without an actual increase in number of extreme weather events (disasters involve people and property). This pattern is happening in the US and it is possible it is global (have not researched the global aspect yet).


    Look at the map of where the billion dollar US disasters are taking place.

    Now combine that information with this map.


    The link above shows that population growth along the coasts has increased 45% since 1970. Now look again at where most the disasters are taking place. Along the coasts.

  191. Norman:

    Hank Roberts @185

    Unfortunately I never did take a statistics course (I wish I had). I have Calculus. I am learning statistics as I go. I certainly would not have your knowledge of the math, but I can learn it.

  192. Norman:

    Thomas Lee Elifritz @184

    I am not using the best of grammar in my communications. It does not mean droughts that cover the globe. Just a global assessment of droughts, the conditions given in the article I linked to would be mean drought duration, number of droughts, and extent of droughts on a global scale (as opposed to a regional or national scale).

    But it is not Norman Page the petroleum geologist. I am Norman Grinvalds just a lab tech. No PhD for me. I think I posted once or twice on WUWT. I mainly was posting on Skeptical Science.

  193. John Pollack:

    Norman @165 I looked at the climate change indicators that you referenced. Of course, the data goes up to about 2008, and misses some recent extreme events. Even within the period you refer to, there is a strong rise in warm minimum temperatures, which now greatly exceed the 1930s. There is also a substantial rise in extreme precipitation events.

    It is not clear to me whether the heat wave index covers the whole year, or merely the summer. If it is the latter, it ignores warm extremes that occur the rest of the year, when extremes are more easily generated by blocking. These extremes, such as our recent warm pattern, can be extremely disruptive to the life cycles of plants and animals, even when they are not uncomfortable to humans (at least, to those without pollen allergies.)

    There is a systematic weakness in these measures of heat which exclude dew points. For example, the Midwest heat wave of July 1995 produced are temperatures which were not extreme compared to the 1930s, but the upper air heights and temperatures were quite extreme. So were the dew points. A lot of people in Chicago died.

  194. Norman:

    John P. Reisman (OSS Foundation)@187

    “The problem is clear, you’re not using science correctly in your analysis, you’re using your own bias confirmation.”

    Here is my position on the topic from my post at 178.

    “It keeps the most important aspect of any science alive, thinking.

    One of the reasons I post on extreme weather threads is it seems too many just accept what is said without thinking about it or investigating the claims on their own. Doing some research.”

    I am not staking a claim I am right, I am questioning what seems to be a lack of questions and more just accepting based on authority. Science lives when those in it raise questions. I am not sure many people actually look into past weather or climate to see what has already happened when it comes to extreme weather events. You may believe my path to be misguided but I am old fashioned. I like evidence based science. The motto is “prove it!” I have linked to various places which at this time do not show an obvious direction into extreme weather taking place.

    In my own research I was logging wind speeds from thunderstorms (70 knots and above) in the United States. I pasted a copy of an email exchange in Post 99. Wind speed showed these sudden jumps in reported numbers. Where things really getting much worse in very rapid fashion? I emailed one of the meteorologists in charge of the data and he was kind enough to reply and supply the answers. That indicates a lot of the increase in extreme weather now being reported may not be an actual increase in what is actually happening but just an increase in reporting of what is going on.

    I do link to data and information that does demonstrate my points (not just my opinion of things). As I stated, I like evidence based science. Let the evidence determine the reality of extreme weather.

  195. Tokodave:

    Norman @ 190 As I mentioned there is clearly a cultural (and political…) component to some of the metrics reflecting more extremes but the NOAA map you reference actually shows billion dollar weather events are surprisingly well distributed across the country. It would only make sense that extreme events affecting the coasts are more likely to result in billion dollar costs, that’s where the people/cities/towns are. It’s only going to get worse http://www.skepticalscience.com/Storm-Century-Decade_MIT.html
    The increase in the amount of rain falling as “very heavy precipitation” and relative number of high temperature records compared to cold temperature records are independent measures of the new normal. The sharp nationwide increase in insured losses related to weather and significant weather related U.S. electric grid disturbances cover the period from 1990 to 2007, so the 45% increase in coastal population since 1970 is unlikely to be a major factor particularly since the highest coastal growth is concentrated in a relatively small number of counties, many of them in Florida. Let’s watch how a higher sea level plays out down there.

  196. John P. Reisman (OSS Foundation):

    #189 Dan H.

    What do you mean by long-term? what is your context for your claims inferences and assertions?

    Decades? Centuries? Millennia? Hundreds of thousands of years? Millions of Years.

    Context is key.

    Therefore time scale and attribution in that time scale is key.

  197. John P. Reisman (OSS Foundation):

    #194 Norman Grinvalds

    Questioning the science is great when it’s done scientifically, but a guy on a blog, looking at regional data and trying to imply that means something globally does not good ‘global’ science make.

    There are no lack of questions in science. The basis of science is questions, boatloads of them.

    Science is examining myriad evidence lines for extreme events and even historical literature, paintings and music to look at correlates in extreme weather. Just because ‘people’ don’t’ does not mean science is not looking.

    Your own local research means nothing globally. Regional variances even with climate change will vary depending on what you are looking at.

    I’ve reviewed studies showing statistical significance on extremes pertaining to global warming. I don’t recall them off the top of my head (you can do some digging if you really want to get to the truth), but you should look at those. The evidence is only getting better in the attribution as more study is done.

    Your own analysis does not change those analyses. And until you get yours published and in context, your analysis does not have significance.

  198. Dan H.:

    So far, no one has shown a clear connection between global warming an increased “blocking,” although much speculation has gone down that road. Conditions existed that created perceived blocking patterns for extended periods in the 1930s, but there is little evidence that these patterns have increased significantly. This is an area to watch in the future, as many are predicting an incrase in extreme heat and cold.

  199. Hank Roberts:

    > Dan H. … So far, no one has shown

    Dan H. teaches the controversy.

    Paste his words into a Scholar search.

  200. Hank Roberts:

    Multiple flow equilibria in the atmosphere and blocking
    Charney et al. 1979

    –> Cited by 605 subsequent papers.

    Charney, Jule G., John G. DeVore, 1979: Multiple Flow Equilibria in the Atmosphere and Blocking. J. Atmos. Sci., 36, 1205–1216.
    doi: http://dx.doi.org/10.1175/1520-0469(1979)0362.0.CO;2


  201. SecularAnimist:

    Dan H wrote: “So far, no one has shown a clear connection between global warming an increased ‘blocking,’ …”


    Evidence linking Arctic amplification to extreme weather in mid-latitudes

    Jennifer A. Francis, Institute of Marine and Coastal Sciences, Rutgers University, New Brunswick, New Jersey, USA
    Stephen J. Vavrus, Center for Climatic Research, University of Wisconsin-Madison, Madison, Wisconsin, USA

    GEOPHYSICAL RESEARCH LETTERS, VOL. 39, L06801, 6 PP., 2012 doi:10.1029/2012GL051000

    Discussion at ClimateCentral:

  202. John P. Reisman (OSS Foundation):

    #198 Dan H.

    Why do you make claims that are popular on denialist blogs without checking up on the scientific literature first?

  203. Norman:

    March 2012 is out on the NOAA web page and it is really exceptional for area that was warm in US and how warm. There are very few like it but in searching I did find a year that did look somewhat similar. October 1963.

    Here are the links for your own viewing.
    October 1963


    March 2012


  204. Ray Ladbury:

    Google Extreme Value Theory, and then perhaps you can talk out of the proper orifice.

  205. Daniel Bailey:

    Umm, Norman, aside from the issue of your links not working, you must really compare like-to-like. As in March-to-March, or October-to-October, with the year being the variable.

    Same apples=oranges improper analytical thinking and cognitive bias cherry-picking as in his SkS iterations.

  206. Tokodave:

    Put another way; if it’s 30 or 40 degrees warmer than normal in March that’s pretty damn warm for that time of year….were it 30 or 40 degrees warmer than normal in August….that’s hell or high water country… http://tamino.wordpress.com/2011/05/07/hell-and-high-water/

  207. Hank Roberts:

    That illustration is of a pick mattock and scythe, just to be, er, picky. Restoration tools.

    Every time I see an eagle on a stick, I think of Julius Caesar, oh, wait, I mean George Washington. And you know the rule about mentioning the fyflot.

    Ok, that ends _this_ exchange, I trust.

  208. grypo:


    Hoerling’s take on Stefan Rahmstorf and Dim Coumou

    — Not a scientific paper, but more Op-Ed

    — Exaggerated language, and many unsubstantiated assertions.

    — Overly simplistic view of the relation between damage, human suffering, and the extremes. Much more balanced arguments can be found in R. Pielke Jr.’s work

    — Very few of the [cases of extreme weather listed in the paper] have undergone a scientific investigation of contributing factors, let alone human impacts.

    — The piece lacks all perspective on the human and technological elements contributing to greater observational capacity to sense extremes

    — The matter of attribution, as raised in the second to last paragraph, is a much broader science that merely determining the change in probability due to greenhouse-gas forcing

    — Consistent with the policy-direct tone of this piece, hyperbole is used throughout.

    [Response: He doesn’t appear to be reading the same paper that I saw – or perhaps he wanted them to write about something else entirely. Either way, this is not a constructive addition to the general discussion. – gavin]

  209. Norman:

    Dan H. @198

    I was able to find this thesis from a student to obtain a Master’s Degree. He does show a sharp increase in the number of blocking events and the duration, but the intensity drops off. He adds global and Northern Hemisphere temperature anomalies to the blocking pattern graphs.

    I thought you may find this thesis of interest.


  210. Dan H.:

    Very nice.
    The paper found an increase in the duration of blocking events, but a decrease in intensity with increasing temperatures. The major impact of blocking events appears to be the PDO; increased blocking in the northern hemisphere during the negative phase of the PDO, and an increase in the southern hemisphere during the positive phase.