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Warmer and warmer

Filed under: — rasmus @ 13 September 2010

Are the heat waves really getting more extreme? This question popped up after the summer of 2003 in Europe, and yet again after this hot Russian summer. The European Centre for Medium-range Weather Forecasts (ECMWF), which normally doesn’t make much noise about climate issues, has since made a statement about July global mean temperature being record warm:

Consistent with widespread media reports of extreme heat and adverse impacts in various places, the latest results from ERA-Interim indicate that the average temperature over land areas of the extratropical northern hemisphere reached a new high in July 2010. May and June 2010 were also unusually warm.

Here, the ERA-Interim, also referred to as ‘ERAINT’, is the ECMWF’s state-of-the-art reanalysis. But the ERAINT describes the atmospheric state only since 1989, and in isolation, it is not the ideal data set for making inferences about long-term climate change because it doesn’t go all that far back in time. However, the statement also draws on the longer reanalysis known as the ERA40 re-analysis, spanning the time interval 1957-2002. Thus, taken into context of ERA40, the ECMWF has some legitimacy behind their statement.

The ERAINT reanalysis is a product of all suitable measurements fed into a model of the atmosphere, describing all the known relevant physical laws and processes. Basically, reanalyses represent the most complete and accurate picture that we can give for the day-to-day atmosphere, incorporating all useful information we have (satellites, ground observations, ships, buoys, aircrafts, radiosondes, rawinsondes). They can also be used to reconstruct things at finer spatial and temporal scales than is possible using met station data, based on physical rules provided by weather models.

The reanalyses are closely tied to the measurements at most locations where observations – such as 2-meter temperature, T(2m), or surface pressure – are provided and used in the data assimilation. Data assimilation is a way of making the model follow the observations as closely as possible at the locations where they are provided, hence constraining the atmospheric model. The constraining of the atmospheric model affect the predictions where there are no observations because most of the weather elements – except for precipitation – do not change abruptly over short distance (mathematically, we say that they are described by ‘spatially smooth and slowly changing functions’).

There are also locations – notably the in the Polar regions and over Africa – where ground-based measurements are sparse, and where much is left for the weather models to predict without observational constraints. In such regions, the description may be biased by model shortcomings, and different reanalysis may provide a different regional picture of the surface conditions. Surface variables such as T(2m) are strongly affected by their environment, which may be represented differently in different weather models (e.g. different spatial resolution implies different altitudes) and therefore is a reason for differences between reanalyses.

Furthermore, soil moisture may affect T(2m), linking temperature to precipitation. The energy flow (heat fluxes) between the ground/lakes/sea and the atmosphere may also affect surface temperatures. However, both precipitation and heat fluxes are computed by the reanalysis atmosphere model without direct constraints, and are therefore only loosely tied to the observations fed into the models. Furthermore, both heat fluxes and precipitation can vary substantially over short distances, and are often not smooth spatial functions.

While the evidence suggesting more extremely high temperatures are mounting over time, the number of resources offering data is also growing. Some of these involve satellite borne remote sensing instruments, but many data sets do not incorporate such data.

In the book “A Vast Machine“, Paul N. Edwards discusses various types of data and how all data involve some type of modelling, even barometers and thermometers. It also provides an account on the observational network, models, and the knowledge we have derived from these. Myles Allen has written a review of this book in Nature, and I have reviewed it for Physics World (subscription required for the latter).

All data need to be screened though a quality control, to eliminate misreadings, instrument failure, or other types of errors. A typical screening criterion is to check whether e.g. the temperature estimated by satellite remote sensing is unrealistically high, but sometimes such screening may also throw out valid data, such as was the case of the Antarctic ozone hole. Such post-processing is done differently in analyses, satellite measurements, and reanalyses.

The global mean temperature estimated from the ERAINT, however, is not very different from other analyses or reanalyses (see figure below) for the time they overlap. We also see a good agreement between the ERA40 reanalysis, the NCEP/NCAR reanalysis, and the traditional datasets – analyses – of gridded temperature (GISTEMP, HadCRUT3v, NCDC).

Do the ERAINT and ERA40 provide a sufficient basis for making meaningful
inferences about extreme temperatures and unprecedented heat waves? An important point with reanalyses, is that the model used doesn’t change over the time spanned by the analysis, but reanalyses are generally used with caution for climate change studies because the number and type of observations being fed into the computer model changes over time. Changes in the number of observations and instruments is also an issue affecting the more traditional analyses.

Since the ERAINT only goes as far back as 1989, it involves many modern satellite-borne remote sensing measurements, and it is believed that there are less problems with observational network discontinuity after this date than in the earlier days. It may be more problematic studying trends in the ERA40 data, due to huge improvements in the observational platforms between 1958 and now. Hence, it is important also to look at individual long-term series of high quality. These series have to be ‘homogeneous’, meaning that they need to reflect the local climate variable consistently through its span, not being affected by changes in the local environment, instrumentation, and measurement practices.

An analysis I published in 2004, looking at how often record-high monthly temperatures recur, indicated that record-breaking monthly mean temperature have been more frequent that they would have been if the climate were not getting hotter. This analysis supports the ECMWF statement, and was based on a few high-quality temperature series scattered across our planet, chosen to be sufficiently far from each other to minimize mutual dependencies that can bias the analysis.

The ECMWF provides data for some climate indices, such as the global mean temperature, and the National Oceanic and Atmospheric Administration (NOAA) has a web site for extreme temperatures and precipitation around the world with an interactive map, showing the warmest and coldest sites on the continents. Another useful tool is the KNMI ClimateExplorer, where people can both access data and carry out different analyses on line. It is also possible to get climate data on your iPhone/iPod Touch through Apps like Climate Mobile.

Update: I just learned that NOAA recently has launched a Climate Services Portal on

Update: is another site that provides station-based climate data. The site shows linear trends estimated for the last 50 years.

532 Responses to “Warmer and warmer”

  1. 101
    Radge Havers says:

    But he came in, guns blazing, not because he didn’t understand, but because he won’t, and he won’t trust the experts to teach him.

    And sometimes people just enjoy behaving badly. There’s alot of that out there too.

  2. 102
    SecularAnimist says:

    Regarding the (off-topic?) discussion of science education, and putting aside Edward Greisch’s denigration of the humanities, and putting aside the fact that among the most ardent and activist proponents of action against AGW there are many musicians, writers, artists and filmmakers, and putting aside the fact that among the most obstinate and willfully ignorant denialists there are a considerable number of engineers and other technical types who have exactly the sort of educational background that he suggests as an antidote to denialism:

    The real problem is that we simply don’t have time to address AGW by making changes to fundamental institutions of human cultures, whether those be education, or religion, or government, or economics, or the pathological anthropocentrism that at present pervades them all, and then waiting for a few generations for those changes to transform all the various human societies around the globe into ones that are prepared to fully recognize and deal with the problem.

    I don’t doubt that improving science education would improve human societies in many ways. But I don’t see how it will produce steep reductions in GHG emissions within 5-10 years, and a nearly complete phase-out of fossil fuel use within 10-20 years at most, which is what is needed to avoid catastrophic warming, if indeed it is not already too late to do so.

    To paraphrase a former US government official, you have to address global warming with the level of public scientific literacy you have, not the level of public scientific literacy you wish you had.

  3. 103
    David B. Benson says:

    Laws of Nature @99 — Here is a simple way to see that the effects of rising CO2 concentrations far outway the internal variaility indexed by the AMO:

  4. 104
    Paul Tremblay says:

    Laws of Nature: “Frankly I am a little shocked about the lack of a solid scientific reply!”

    Really? When I pointed you to peer reviewed studies that show the urban heat islands had no effect on the accuracy of the temperature record, you replied with a personal anecdote. We’ve pointed out logical reasons why AMO and solar activity cannot account for the warming trend, and you ignore our responses and more doggedly repeat your own assertion.

    The answers to your so-called questions (which, by the way you defended them, were really arguments), especially on solar activity, can easily be found anywhere on the web. Obviously, you are not trying too hard to find a real answer. Nor are you trying too hard to actually understand the responses here.

  5. 105
    SecularAnimist says:

    Edward Greisch wrote: “Science is about laboratory experiments.”

    That seems to be an odd thing to say on a blog about climate science, which as I understand it, has relatively little to do with “laboratory experiments”.

  6. 106
    Anne van der Bom says:

    Laws of Nature 16 September 2010 at 11:39 AM

    based on a presumed effect of ocean oscillations on the climate (it’s not just me who assumes this exists!) + the well known assumption, that the sun variation affects the climate +others (including issues with the measurement of the temperature record),

    That’s a nice summary of your proposition that you’re giving there. In other words: I have these two oscillations that could cause the rise in temperatures, and if they don’t then it’s the UHI that can explain the difference.

    And then you are amazed that people get irritated and don’t take you seriously? And then you start playing the victim.

    I asked a question, nothing more, nothing less
    However the accusations…
    Apparently I am deeply misunderstood ..
    frankly I am a little shocked about the lack of a solid scientific reply!

    You gotta be kidding me. You must have more social intelligence than that.

    Your ‘hypothesis’ is utterly boring and whether you’re playing the devil’s advocate is irrelevant. It is, so to speak ‘from page 1 of the Denialist Handbook’:
    1. Find some correlation (not necessary to offer any supporting evidence or mechanism, just the suggestion of a correlation will suffice) and suggest it explains the warming
    2. Lay the burden of proof with them. They are so smart, they have to disprove it
    3. Reject any evidence that they might bring up out of hand. If they get you in trouble, invoke the hockey stick or urban heat island or start complaining about how nasty they are.

    Laws of Nature, if you are not getting out of this discussion what you are looking for, don’t automatically assume it’s the others’ fault. It takes two to tango and by invoking the UHI, you have disqualified yourself from deserving any serious answers. The UHI is the single most debunked denialist talking point in existence. It is tiresome and very offensive, as if the scientists working on those datasets haven’t got a clue about what they’re doing. As such, it’s a huge red flag.

    You’ll need to start asking solid scientific questions if you want a solid scientific reply.

  7. 107
    Paul Tremblay says:

    I’ve worked in public education for 15 years, and there exists a huge gap between what the public thinks goes on in high school, and what really goes on. Let’s take an average high school of 400 students that offers 1 AP (advanced placement) physics class. Let’s say it is a good high school, so 30 students take that class.

    Of those 30, I would say that only 15 would ever care enough about the details of global warming to try to find out more information, including reading a blog like Real Climate. The other 15 students are simply taking the class to get into a better college, and have no interest in detailed abstract thinking, and would be happy if they never had to pick up a physics book again.

    So far we have 15 students even willing to engage their minds in this problem. Now what about the students in the other classes? Forget it. I mean, really, really, forget it. Most of these students couldn’t even tell you what AGW is, and grow very hostile if you even gently tried to explain it in the simplest terms. Just to give you an idea of the level of these other students, many (perhaps 50%) lack the reading skills to comprehend a book like *Walden* or *A Tale of Two Cities.* Shakespeare mind as well be written in Greek.

    So why do high schools teach Shakespeare when most of the students can’t even comprehend the actual language? Mostly because no one wants to admit the problem, and it looks good to say that such and such a high school has the students read a play by Shakespeare each year.

    Consider what this means if we start mandating that students take more science courses. Yes, the students will take them because they have to. And yes, they will pass, because the teachers will dumb down the material. But the students won’t be one iota smarter for these mandated courses. As it stands now, because of absurd pedagogy, many school require special ed students to take algebra. I remember teaching one, sweet, lovable girl who literally had the development of a 5-year old. “Okay, Ashly, X + X = 2x. Now what does X + X =?” Response: “100?”

    I say this only to try give a picture of how futile a pursuit it would be to try to educate the public through the education system. I am not trying to denigrate our education system as a whole, or the students. The reason for the lack of learning has partly to do with our culture, which also has a hostility to real critical thinking; but it also has to do with the fact that many students simply can’t think on the abstract level.

    I suspect that many will think I exaggerate my claims about the lack of learning that occurs in high schools. However, my current job involves scoring the standardized tests high schoolers take. The other scorers constantly express their amazement at how bad the tests are, at how little the high schoolers know. I get bored with this amazement because I have seen it for 15 years.

    Also, here is an example of where our high school students stand:

    Admittedly, that’s not much in the way of evidence, but I personally think it should at least give a snap shot.

    Again, I am not saying we need to give up on educating people about AGW. Even simple-minded people who don’t have a high school diploma can understand the dangers of it, if they get a clear message, rather than the mixed message put out by our media. Likewise, as another poster astutely pointed out, simply having a good grounding in science does not mean you won’t be a denier, as we we not only in some excellent climatologists, but even some posters on this board.

  8. 108
    Radge Havers says:

    SecularAnimist @ 102

    True enough, however I have a sinking feeling that it may be necessary to begin preparing upcoming generations to deal with the consequences.

    I for one don’t have a lot of confidence in the status quo.

  9. 109
    Tom Curtis says:

    Roddy Campbell (@94): :

    “‘…….. a variety of ideological blinkers that make the truth unpalatable (in others). As the examples of Plimer, Pielke, and Curry demonstrate, no amount of education will overcome these impediments.’

    Gosh that’s quite strong isn’t it? Pielke (either one?) and Curry are so ideologically blinkered that they cannot see truth? My word. Are you sure they are the only ones with blinkers?”

    Judith Curry:

    Roger Pielke Jr:

    Given their respective qualifications and academic experience, we cannot attribute these gross errors to incompetence or lack of intelligence or education. So what do you attribute it to; deliberate dishonesty, or as I do, to some combination of laziness and/or ideological blinkers? And to avoid misunderstanding, the problem in each case is not that they made mistakes, but they way they responded to criticism of their mistakes and evaded admission of error.

    “And re your next para, prizes of great standing, Al Gore won one, but I’m not sure it had the effect you suggest?”

    It is precisely because Al Gore has been so effective a persuader that he has been subject to so much unwarranted criticism by AGW denialists; and you can be sure his receipt of a Nobel Prize will have increased his persuasiveness to uncommitted readers.

    However, my claim is not that introducing science writter awards sufficiently prestigious that the general public know of thier existence will be some sort of silver bullet. Nor even is it that it would be preferable in general terms to improving education (which ought to be done for its own sake). Rather, it is that such awards would be one of the few things we can do to influence the balance of the “debate” in favour of science in a time frame short enough to accelerate effective policy responces to AGW.

    It is my belief that AGW denialism will be rendered ridiculous in the public mind within 10 to 15 years as glaciers melt and the North Pole becomes icefree in September. Education reforms will not have an appreciable effect on public opinion till well after that. Changing the media so it reports on AGW opinions in proportion to how many experts hold those opinions (or better yet, how well founded those opinions are) rather than in inverse proportion as is now the case cannot be achieved by legislation with a free press, nor by public pressure without first massively changing public opinion. So unless your of the Forbes 100 list, and plan to buy out Newscorp, changing media reporting is not on the cards (although competition by reporters for the award might have some effect).

  10. 110
    Thomas says:

    I do think theory/explaination wise straospheric cooling and surface warming are largely separable effects. Stratospheric cooling can be simply explained by two things, (1) constant UV heating of the stratosphere, coupling with more IR opacity (due to increasing straposheric CO2), and (2) the fact that if we posit the atmosphere is in thermal equlibrium (i.e. net energy in equals energy out), then the net upward IR flux through the stratosphere is unchanged, but the greater level of CO2, means that less of it will be in the CO2 bands, so the stratostrophic CO2 molecules will also see slightly less IR inputs as well as less (per stratospheric CO2 mlecule) less UV inputs. To understand the surface warming, one has to create and solve for atmospheric temperature including both radiation and convective effects. So at least in terms of theory development they can be separated. Of course a good model for solving for the atmospheric temperature profile, will also predict straosheric cooling, but a rather simplified model can explain the straospheric cooling.

  11. 111
    freetoken says:

    @107 Paul Tremblay says:
    “I say this only to try give a picture of how futile a pursuit it would be to try to educate the public through the education system. I am not trying to denigrate our education system as a whole, or the students. The reason for the lack of learning has partly to do with our culture, which also has a hostility to real critical thinking; but it also has to do with the fact that many students simply can’t think on the abstract level.”

    There is insight in what Paul has written, in his entire comment.

    I do not believe a change in the policies and practical efforts (wrt AGW mitigation and adaptation) in this country will come about just by diddling with the curricula of our schools. If there is to be a change, the education system may have not much to do with it.

    Public opinion polls have shown consistently that the majority of the American public accepts that there is at least some evidence for AGW, yet lifestyles on the whole are not changed by that belief.

    For 3 decades I’ve dealt off and on with creationists and their denial of science, and what I’ve learned from that experience has shown me that people believe what they have to in order to make sense of their lives. What they believe doesn’t have to be true (in a scientific sense), it just has to work for them.

    The attribution question is a very interesting one to watch as an outsider to the climatology community, as I see that community wrestle with how to influence the public and answer very thorny questions. Upstream someone mentioned tobacco, and there are parallels to the tobacco-science wars of a few decades ago. Attributing death due to lung cancer was important in turning the tide against unfettered tobacco use in this country. However, the policy success of attribution was helped greatly in the public’s mind by seeing actual lungs from dead people cut open for them to see. Unfortunately for the AGW community there are no similar visual, visceral, smoking guns. Sorry, but cute polar bears swimming in the open sea just isn’t equivalent.

    So the attribution issue is important, no doubt. I’ll watch and see over the next few years how much progress, if any, is made.

  12. 112
    Rattus Norvegicus says:

    Paul Tremblay:

    As far as lit goes I really, really agree with you. I did the obligatory Shakespeare and Melville in High School. Wrote the necessary papers. Found both boring beyond description.

    Funny thing is that I never really got the stuff when I was an adolescent. 15 years later, watching “Ran” I finally got Shakespeare. When I read “Moby Dick” at age 40+ I finally appreciated it and understood how brilliant it was. The atheist theme (preaching to the sharks, the best scene for this one, but there are others) completely passed by me.

    Looking back sometimes I think that high school is the wrong time to introduce deep thinking. Crikey during most of that time I was thinking about sex (and not getting any, either…), not to mention drugs and rock ‘n roll. I did get interested in biology (marine) and chemistry (physical, well and darkroom…) so I suppose my science teachers were not completely unsuccessful…

  13. 113
    Brian Dodge says:

    “The sunspot numbers (which serve as an example only, the sun effect is for experts to discuss) are pretty high in the 2nd half of the 20th century,
    if that has any indcation for the temperature (wheat prices!), the sun may contribute to the warming .. Scarfetta estimates up to 30%.”
    Laws of Nature — 15 September 2010 @ 10:09 AM

    I downloaded monthly sunspot numbers, HadCRU temperature anomaly, and CO2 concentration from, and plugged the data into an online regression tool at

    for Sunspot number versus temperature anomaly I got
    Result: y = -2.229690534·10-4 x + 1.801811457·10-1
    Correlation Coeficient: r = -5.143542793·10-2
    Residual Sum of Squares: rss = 24.67434614

    for CO2 concentration versus temperature I got
    Result: y = 1.014357422·10-2 x – 3.427986543
    Correlation Coeficient: r = 8.457180975·10-1
    Residual Sum of Squares: rss = 7.044927084

    I’m well aware that a correlation of 0.85 for CO2 to temperature doesn’t necessarily prove causation, but conversely the lack of correlation, -0.05, of SSN with temperatures is a strong argument against the influence of sunspots on the recent increase in global temperatures.

  14. 114
    Laws of Nature says:

    #97 “You are ignorant..” then citing a study which links the temperature changes of the 19th century mostly to vulcanism drawing the conclusion,
    that the 19th century would have been warmer without it
    => that would strengthen my case for the Atlantic oscillation
    #100: “solar effects can account for only a fourth of the net change in climate forcing in this 140 year period”
    #103 gives a link, which interpret that the Atlantic AMO might contribute about 0.1K to the warming?

    Which of them is right
    On top of that a lot of accusation that I would come in “guns blazing, not because he didn’t understand”
    Actually I thing we are slowly starting into a serious discussion . .
    Up there are at least soemthing like a basis..

    So if I would take the statements above serious, I would conclude that from 0.8K warming (or less according to Tamino’s study)
    about 0.2K could be from the sun (or less according to Tamino’s study), about 0.1K in the recent 40years could be from the Atlantiv AMO and perhaps 0.1K due to UHI
    (I know that we would ignore some peer reviewed studies saying there is no UHI this way) or other measurement issues
    Leaving about 0.4K measured warming (with perhaps more in the pipe) which can be attributed to CO2+feedback.

  15. 115
  16. 116

    Lawsy 99,

    Yes, the AMO does affect the year-to-year variation. When I regress NASA GISS temperature anomalies on ln CO2 and the AMO, CO2 accounts for about 76% of the variation, and the AMO accounts for another 12%. Solar effects are minor and usually not statistically significant.

  17. 117
    Silk says:

    “perhaps 0.1K due to UHI”


    Zero due to UHI. Zero! Because it has been shown that UHI has zero effect on estimates of global mean temperature.

    And zero heating, more or less, is due to the sun BECAUSE THERE IS NO TREND IN SOLAR ACTIVITY OVER THE PERIOD.

    Look at post #112

  18. 118

    #114–Oh, the irony! And in the year and a half since, Steve McIntyre hasn’t offered any support for the Benestad/Schmidt call for openness and transparency?

    “What’s up with that?”


  19. 119

    91 (Rod B),

    …you say that most of the energy leaving the system via IR emission (from CO2 in your example) is sourced from insolation, which would mean that only a small portion of the escaping CO2 radiation energy originates from earth’s IR.

    This isn’t an entirely wrong interpretation, but there may be things you are misunderstanding behind this. I think the source of your confusion may be in not realizing that “the system” in this case is the stratosphere alone, not the entire earth.

    For a fairly simple explanation, see Stratospheric Cooling.

  20. 120
    Roddy Campbell says:

    #109 Tom Curtis replying to my 94:

    Tom, thank you for replying.

    I’m still not with you – you link to a couple of Tim Lambert’s Deltoid blog posts on Pielke and Curry, and I followed the Curry Hockey Stick episode here and on other blogs at the time. (I think Zorita is more or less right on that one).

    Apart from the irony of using a Deltoid blog to try and show that those two suffer from ‘ideological blinkers’ (don’t get me wrong, I enjoy Deltoid, in good part because he is so honest about where he is coming from that I know where I stand), the posts you link to in no way show an inescapable conclusion of ideology as far as I can see, and I stand by my position of incomprehension that you would discount anything those two say on grounds of proven ideological bias. Not being rude, but I get the feeling that the conclusion is more that you don’t agree with them, and don’t understand how they can hold some of the views they do, which is not the same thing as ideological bias.

    ‘And to avoid misunderstanding, the problem in each case is not that they made mistakes, but they way they responded to criticism of their mistakes and evaded admission of error.’ – that did give me a good laugh! Can you see the irony?

    As it says in the Lambert post, Pielke immediately admitted error (the issue was counting stories on a particular subject, hurricane papers, presumably using Google – not exactly the most critical climatological skill), calling himself ‘sloppy’.

    re Gore, you say ‘….you can be sure his receipt of a Nobel Prize will have increased his persuasiveness to uncommitted readers.’ – not by much imho, if at all, it was the movie that had the effect. So promoting movies might be more effective than science prizes.

    Despite your wariness of Pielke Jr, you will enjoy his recent post on belief,, which has a lot about belief systems determining one’s attitude to AGW, and does not spare the rod from the libertarians.

  21. 121
    Laws of Nature says:

    Re #106 and #117
    If you could precise your statement about the UHI for me please:

    – are you saying there is no effect for example when you watch a thermometer at your car and drive from a counrtyside into a city

    – are you doubting that the growing of cities automatically puts measurement stations into a different environment (improper to the rules the stations were built)?

    I understand that you can cite studies which do not find any UHI, but wonder where precizely we start to disagree on this effect.

    [Response: The heat island effect is 100% inconsequential to global T trends relative to the effect of greenhouse gasses. Been analyzed and discussed to death and back. No more trolling.–Jim]

  22. 122

    Laws of Nature,

    The AMO flipped from negative to positive around 1995, so by your logic, it was holding temperatures down and masking the effects of CO2 prior to then, perhaps as far back as 1965. At a minimum, the net contribution of AMO to global temperature increases from 1980 to the present is zero (15 years of cooling from 1980 to 1995, 15 years of warming from 1995 to 2010), meaning that all of the warming over that 30 year period is attributable to CO2. And at worst, it also cooled the globe from at least 1965 to 1980, which means that CO2 warming in that period was actually much greater than is evidenced by the current temperature record, but will not measurable until one full cycle of negative/positive AMO plays out.

  23. 123
    dhogaza says:

    – are you saying there is no effect for example when you watch a thermometer at your car and drive from a counrtyside into a city

    The fact that cities may be warmer does not necessarily mean that this effects the trend, any more than a thermometer that reads 1 degree high at all ties doesn’t effect the *trend*, which depends on changes in temperature, not the actual indicated temperature.

    – are you doubting that the growing of cities automatically puts measurement stations into a different environment (improper to the rules the stations were built)?

    This is an unsubstantiated claim. A guess on your part which you’re parroting after having read climate denialist sites which put forward this guess as being an undisputed fact.

    There’s plenty of reason to doubt this.

    And your argument totally ignores the question as to whether or not it is possible to *compensate* for any such UHI.

    I understand that you can cite studies which do not find any UHI, but wonder where precizely we start to disagree on this effect.

    To my knowledge, there is no credible peer-reviewed study that shows any statistically significant effect on trend due to UHI.

    People have computed trends using raw data, adjusted data, rural-only data, Anthony Watts “best stations only” data, etc etc including several reconstructions by people with at least one foot in the denialist camp and the same trend pops out.

    When many groups of people treating various subsets of adjusted and raw data using a variety of statistical approaches all come up with almost exactly the same trend, the evidence is strong is that such reconstructions are robust.

    The only significant difference lies in how one treats the arctic, i.e. ignore it or extrapolate station data.

    And the topper, of course, is that satellite reconstructions show the same bleeping trend.

    If you want credibility, you’re going to have to drop the “world is not warming” crud. Even Anthony Watts has apparently shelved the statistical analysis based on his surface stations photography project, which is a year or more late, presumably because he gets the wrong answer … others *have* done the analysis and have shown that slicing the dataset using Anthony’s razor shows no statistically different trend.

    Deal with it.

  24. 124
    Rick Brown says:

    Law of Nature @121:
    “I understand that you can cite studies which do not find any UHI, but wonder where precizely we start to disagree on this effect.”

    Just a bored bystander here, but it seems that where you start to disagree with Anne and Silk is that you want to rely on personal anecdote and thinking about things while they are relying on published scientific evidence.

  25. 125
    dhogaza says:

    And further … the UHI is not a “law of nature”. Maybe you should stick to subjects that reflect favorably on your chosen nom de web?

  26. 126
    Rod B says:

    SecularAnimist, saying this makes me vaguely nervous, but from your perspective your points in #102 are right on target and realistic, IMO.

  27. 127
    Rod B says:

    Anne van der Bom, your three points in #106 can apply equally to AGW proponents, except for that ‘invoke the hockey stick’ part.

  28. 128
    Rod B says:

    Paul Tremblay, your description of high school and its students in #107 is diametrically opposed to my observations. Though it’s possible my experience is limited to what might be a public school different from the “norm”.

  29. 129
    Susan Anderson says:

    re education (and those are excellent points) I observe that when it comes to sports statistics or the details of American Idol, the American public has no trouble at all keeping track.

    Somehow the prevailing prejudice against learning and lack of respect for teachers must be bypassed and people taught that they *are* capable of connected thought.

    One possible route is the article above, where people need to learn that when clusters of weather events over time point in the direction of climate change, they are to stop denying the evidence of their own senses. I know the caveat about single events not being due to global warming is distracting and easily exploited, but I do think it is possible to get people to broaden their horizons to include decades and the whole globe. Reporters could help by covering more international news.

    While the fake skeptics will keep exploiting local short-term events, the confused recipients of this information can’t help but notice the increase and clustering of extreme weather of all kinds in their own and their family’s lifetimes. Gardeners cannot help but be a good resources. While every time I mention some oldster’s comment about how much more bays used to freeze over some denier sneers at me with some historical event that shows I’m full of it, I think ordinary people are capable of taking it in. Perhaps at some point they will begin to notice that they are being fed by the “side” they’d like to believe in favor of inaction, and begin to distrust their political “friends” a bit less.

    As an artist I taught drawing for many years, and would speak as strongly in favor of the truth in drawing (a lie there is soooo obvious!) as so many here do about truth in science. It’s a matter of abandoning preconceptions and trusting your own eyes, giving up props and getting on with doing the best one can. The result is almost miraculous.

    119: Thanks for the link on stratospheric cooling. It may not have helped its target but did help me!

    The article in ScienceDaily cited above was an eye opener (Laws of Nature, this explains you pretty well):

    Human evolution and mental lack of same may contain the seeds of its own demise. My thoughts turned to Attila the Hun and other barbarian invasions lately as a metaphor for our current political situation: invasion of the barbarians in the form of charismatic people like Palin, O’Donnell, and Paul! Lately I’ve been longing for more Mike Huckabee, whose remarks about science are very sensible – now if he would just abandon his regressive tax ideas, but I’m wandering …

  30. 130
    Ike Solem says:

    You’re conflating fluctuations arising out of fluid dynamics with periodic mechanical driving forces, Bob. (#122)

    For example, if you go to the Arctic Ocean you will observe daily and yearly fluctuations in temperature that are directly linked to Earth’s spin on its axis (time of day) and the axial tilt relative to the sun (time of year). Both of these processes – orbital and rotational movement – are clearly periodic. The actual driving force is the amount of sunlight received at the Earth’s surface. You’ll also notice a periodic rising and falling of the ocean surface – the tides, which are also generated by orbital forcing.

    Now, you will also notice that winds and currents in the Arctic Ocean and overlying atmosphere are not constant, either in strength or direction. There is no apparent direct link to any periodic physical process, but there is the appearance of periodicity – it goes one way, it goes another. This oceanic counterclockwise / clockwise rotation shift, along with the atmospheric pressure differential between midlatitudes and polar regions, cannot be directly linked to any mechanical oscillator.

    In contrast, the ocean tides are clearly linked to orbital mechanics. One can’t create a projection of future changes in the Arctic oscillation with any confidence, but tide charts can be drawn up years in advance. Winds can shift tides a little, but the fundamental factor is the position of the moon, earth and sun.

    As with the AO, with El Nino and the Southern Oscillation there’s no mechanical oscillator. Studies of the initiation and termination of El Ninos point instead to a series of positive feedbacks that build up and eventually get quenched – a buildup of energy leading to a structural reorganization, then a collapse back to the earlier state, then a buildup of energy.

    Similar processes might include the vegetation growth/wildfire cycle in semi-arid ecosystems, or rock avalanches in mountain zones with a strong freeze-thaw cycle. Notice here that nobody talks about the “phase” of the cycle – although an accumulation of dry brush does point to a higher likelihood of fire, you can’t draw “fire charts” the way you can with tide charts. Project the fire season intensity in California in 2015, please? Not likely.

    Going back to tides and orbital mechanics, you can indeed get an alignment of the various orbital cycles that maximizes or minimizes the tidal change. “Hmmm,” says the denialist – “We can work with this.” Alan Watts seems particularly enamored of this approach – make the temperature increase the result of cycle alignment.

    This is where the claim that global warming is due to an alignment of all these ‘natural’ ocean basin and atmospheric fluctuations originates – but it doesn’t work. Such mechanical analogies are not representative of the behavior of internally generated fluctuations in fluid dynamical systems, and this is clearly seen by comparison with externally generated oscillations like the tides.

    To conclude: You cannot claim that natural cycles are responsible for global warming while maintaining any scientific credibility. The fossil CO2 hypothesis is simpler and more plausible, and the behavior of the climate matches projections made in the late 1970s on the basis of that hypothesis.

  31. 131
    Didactylos says:

    “Laws of Nature”: your big, big error (the one that makes everything else nonsense) is thinking that we think that the Urban Heat Island effect does not exist.

    It exists.

    We know it exists.

    We have known for rather longer than you have.

    And it is of no consequence. No matter what method is used to correct for UHI (including completely ignoring every weather station that just even might be affected) – every method comes to the same conclusion.

  32. 132
    Paul Tremblay says:

    Laws of Nature:

    >>I understand that you can cite studies which do not find any UHI, but wonder where precizely we start to disagree on this effect.

    That link will give a more detailed explanation:

    At the top of the page, it notes that “anomalous urban trends are homogenized to match rural records.” In other words, the UHI effect is known and corrected for.

  33. 133
    Paul Tremblay says:

    >>invasion of the barbarians in the form of charismatic people like Palin, O’Donnell, and Paul! Lately I’ve been longing for more Mike Huckabee, whose remarks about science are very sensible – now if he would just abandon his regressive tax ideas, but I’m wandering …

    I happen to be sympathetic to your views, but I really think it is a bad idea to bring politics into the debate. That just encourages people on the other side to make their own attacks, and makes me want to respond, and pretty soon we have another (meaningless) political online debate, not why I come here. I kept criticizing Rod W. Brick for making politically charged statements, and feel I would by hypocritical to not criticize my own side.

  34. 134

    AMO, AO, PDO and NAO etc, have been played by contrarians, especially Accuweather types, as a means
    to dismiss AGW, which for them is a mere inconsequence of Oceanic temperature fluctuations. All and usually without a clue about what causes a Pacific decadal oscillation, and so its easy to blame the great sst cycles for everything.
    THis sort of argument is met 101 childish. Its been my observation that these oscillations are caused by planetary wave wind inducements, namely the greatest cycle; ENSO is purely triggered by a planetary wave causing favorable winds which bring up or not colder Pacific equatorial waters. The same goes for all the other Ocean temperature cycles. Therefore the atmosphere plays a huge role with them, one cycle is not possible without the atmosphere being in a certain systemic pattern. Therefore there are variations in GT’s caused by the interfacing between ocean and air, always changing, but when they become more stable, a cycle starts or ends. So I find it particularly interesting when a meteorologist blames a cycle for everything, since this cycle depends on climate nearly totally. It is possible to consider that a planetary wave may be influenced by a cycle, but it is equally true that this cycle is started by planetary waves. Therefore the complexity of GT variations is exploited by means of simplifying explanations away from a far more complicated world wide climate system. AGW is observed though, including temperature oscillations, and that is what we are observing here, especially me, in front of the NW passage, passable by Paul Allen Microsoft Owner luxury yacht, or simple explorer ships a la Ousland , modern shade of Amundsen, he will be successful by
    the grace of AGW no less. An accomplishment we dare not think about.

  35. 135
    Rod B says:

    Paul Tremblay (133), just for the record my political commentaries are always a response or at least related, not original. None-the-less, thanks for bringing me back to reality after nearly charging Susan’s red flag.

  36. 136
    Susan Anderson says:

    Paul Tremblay, quite right, my sincere apologies. Nobody, please, get going on politics.

    I hope some will take my serious remarks about telling the truth and mental growth arising out of disciplines that are not science seriously, though. We need to get past thinking we can’t talk to intelligent people not trained in science, and assuming that people can’t grow, or that intelligence is only measured in limited ways. That’s why I mentioned sports statistics which are spouted by otherwise supposedly mathematically illiterate people.

    By the way, I have not yet had trouble with captcha. look at it as a xerox of a xerox of a xerox and assume it’s the alphabet.

  37. 137

    130 (Ike Solem),

    Ummm… yes, that was my point, without getting into all of the details… that while AMO is on the upswing, it appears to raise temperatures, but on the downswing, it lowers them, and in effect, isn’t actually changing anything except the observations (i.e. it’s not adding or subtracting heat from the system, just shuffling it around). A pendulum that swings steadily back and forth, in the end, changes nothing. The net of the full 60 year cycle is a wash. The fact that there is a clear underlying positive signal (CO2) is what matters.

    What is confusing about Law of Nature’s stance is that he’s ready to pounce on the recent fifteen years of positive AMO while ignoring the previous 30 years of negative impact. Rather selectively convenient.

  38. 138

    Didactylos (current #134) wrote about UHI:

    “We have known for rather longer than you have.”

    Very true. Guy Callendar was correcting for it in 1938 by classifying the stations he used to construct temperature series according to the characteristics of the “built environment:” rural, small town, urban.

    See here:

    or here:

  39. 139
    D. Price says:

    Certainly one has to be cautious about single events. England suffered a record drought and heatwave in 1976, when global temperatures were at a postwar low. there is a theory that they become more likely in global cooling phases because of sluggish pressure systems.

  40. 140
    Anne van der Bom says:

    RodB 17 September 2010 at 11:06 AM

    Why would they? It is not necessary. AGW is widely supported by mountains of peer reviewed research.

  41. 141
    David B. Benson says:

    Laws of Nature — Please study “The Discovery of Global Warming” by Spencer , Weart:

  42. 142
    Edward Greisch says:

    There is an article at:
    that desperately needs answering by RC right now. Sorry for the interruption.

  43. 143
    Gsaun039 says:

    We just broke our record for the number of days (84) in a year at or above 90 degrees at RDU airport. That record was set in 2007 (83). The 30 year average is 42.

    But as we all know the Earth has been cooling since 1998….

  44. 144
    SecularAnimist says:

    Susan Anderson wrote: “… invasion of the barbarians in the form of charismatic people like Palin, O’Donnell, and Paul …”

    Paul Tremblay wrote: “… I really think it is a bad idea to bring politics into the debate …”

    It is of course up to the moderators of this site to decide what is and is not appropriate to bring into the debate where “the debate” is defined as the comments that are posted on this site.

    With regard to the wider public “debate” about AGW, though, I don’t see how it is a “bad idea” to name names of politicians who deliberately and aggressively LIE to the American people about the reality of anthropogenic global warming and climate change, and who engage in vicious and dishonest attacks on climate scientists.

    It’s rather silly to talk wistfully about improving scientific education and literacy in schools and universities, while ignoring the obvious fact of a multi-million-dollar, generation-long campaign of deceit and sophistry that uses the mass media and bought-and-paid-for politicians to relentlessly hammer the American people with the message that AGW is a “hoax” perpetrated by “liberals” who are (in Rod B’s words) “working to destroy the US”.

    And that is exactly what the individuals that Susan Anderson named bring to “the debate”.

    [Response: This site is not a proxy forum for arguments about politics – there are plenty of places to do that. If you want to discuss specific issues related to climate science that come up in political races, you can – but keep issues specific. If this morphs into a general political food fight, then it will be shut down. Sorry. – gavin]

  45. 145
    RiHo08 says:

    I usually haven’t resurfaced on blog sites as I usually say what I have to say and exit. But here I am again. I also keep on reading nevertheless. The site seems to have wandered from the “global warming is causing more extreme events” theme and if the monitor is interested, maybe another run at going back to the central theme is worth while. This time it is not wind, or fire, but rain. Modern day Pakistan has had monsoon induced flooding of the Indus River causing all sorts of headline grabbing and global warming attributed death and destruction. Yet, as a boy, I had read to me tales by Rudyard Kipling describing the monsoon rampages of the Indus River carrying her cargo of silt to the farmlands and deltas below. Those events, chronicled more than 150 years ago were equally impacting the lives of that area now called the Swat Valley. Isn’t 150 years long enough to call “climate?” It seems to me that the arguement that global warming is prompting extreme; ie, never been seen before, events, smacks of a historical myopia and ignorance. Maybe those expousing such beliefs need to go back to high school as they seem to have missed something in 9th grade history, or at least that is when I learned of such “extreme weather events.”

  46. 146


    I commented at the Times. Let’s see if they print it.

  47. 147
    Paul Tremblay says:

    >>There is an article at dotearth blogs that desperately needs answering by RC right now.

    Indeed! What an infuriating stupid article. One thing that journalists love to do is exonerate themselves for their malfeasance, and this article proves no exception. Revkin wants to excuse himself from the misconceptions surrounding global warming pointing to a rather pointless study. The study shows that ideological bias determines what science we trust, especially with global warming. Wow. Who knew? Next up: new study shows that parents root for their own kids in sports and aren’t objective when judging them against other kids. Ground breaking stuff!

    Anyway, Revkin then produces the same dumb article that has marred American journalism, covering climate change as if it were a horse race. When covering political races, newspaper invariable take this approach. Who is ahead? By how much? How can candidate A catch up to candidate B, and how will the endorsement of Y help or hurt him; how will his controversial economic policies help him get elected? Yet, hardly ever do you see any detailed analysis of the actual positions, and what they will mean for different Americans. We saw this with health care, and we saw it with the war in Iraq. In both cases, studies showed most Americans didn’t understand the basics behind the issues.

    Now we have Revkin committing the same stupidity. He uses Nobel Prize winners to show that opinions on AGW differ according to an ideological bias. After reading the article, one would come away with the feeling that there is a lot of controversy about AGW, that experts come to two different conclusions.

    But no science is determined by the opinions of Nobel Prize winners outside of the field in question! As a science writer, Revkin should know this. The consensus is determined by the actual science, by the evidence. And the evidence points to something quite different than the article implies.

    So here is Revkin trying to exonerate his profession, at the same time producing a shallow, misleading article. Irony is certainly not dead.

  48. 148
    Pete Wirfs says:

    @145 RiHo08

    I’m a novice at this stuff. But it seems to me that cherry picking a single story about a single event 150 years ago is hardly what one would call a \trend\. If one could produce evidence that these events were of equal magnitude *AND* frequency when compared to recent times, then you might have something worth studying.

    You said \…never been seen before…\. I agree with your sentiment here. I’m not surprised anymore when I see this type of misinformation written by people that wish to sensationalize (and sell more papers/books/articles). It would be nice if we could hold them to the same standards that we hold our scientists, but we can’t now, can we? Attempts to do so might be considered censorship. But I must also say that I do not remember seeing the operators of RealClimate ever behave in this fashion.

    I consider WUWT to be all about sensationalism. They’ve gone so over-board that it has become a waste of time to read anymore. But in light of the fact that WUWT is the livelihood for those operating it, they appear to be very successful in selling their product.


  49. 149
    Hank Roberts says:

    RiHo08, Pakistan’s floods continue as the monsoon season has started; they began well before the monsoon:

  50. 150
    Vendicar Decarian says:

    The state of Texas today sued the U.S. Environmental Protection Agency in a federal appeals court in Washington DC, claiming four new regulations imposed by the EPA are based on the ‘thoroughly discredited’ findings of the Intergovernmental Panel on Climate Change and are ‘factually flawed,’ 1200 WOAI news reports.

    “The state explained that the IPCC, and therefore the EPA, relied on flawed science to conclude that greenhouse emissions endanger public health and welfare,” Abbott said. “Because the Administration predicated its Endangerment Finding on the IPCC’s questionable facts, the state is seeking to prevent the EPA’s new rules, and the economic harm that will result from these regulations, from being imposed on Texas employers, workers, and enforcement agencies.”