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All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

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Comments 124951 to 125000:

  1. On the reliability of the U.S. Surface Temperature Record
    Leo G, the cool bias that Menne found was created by the replacement of one kind of instrument with another, at the same locations. The instruments don't last forever, so they must be replaced, even if by the same kind. When that is done, scientists check the new instrument's measurement against the previous one. Any discrepancies in the measurements of the two instruments must be eliminated by changing all the historic temperatures from the previous instrument, or by changing all the future temperatures from the new instrument. In this particular replacement of one kind of instrument with another kind, one specific difference between the two kinds was not detected during that calibration. So the new instruments were reporting slightly cooler temperatures than the old instruments would have, but nobody knew that. Those slightly cooler measurements started happening only recently, because that's when the instruments were replaced. The shift to cooler measurements was not obviously sudden in the average across all stations, because the instruments were not replaced all at once. As more instruments were replaced one by one, the average temperature consequently became progressively cooler. Someone probably would have noticed the pattern eventually, if they had compared the new type of instrument's measurements against the old type of instrument's measurements across a whole lot of measurements. That comparison eventually did happen, by the fluke of the new instruments being worse sited than the old instruments were. (The new instruments were tethered too close to buildings.) When Menne discovered the worse-sited instruments were slightly cooler than the better sited instruments, he tried to figure out why, by looking for characteristics common to the worse-sited instruments. He found they tended to be the new instruments. So then he did the explicit comparison of new instruments against old that I mentioned in the last sentence of my previous paragraph.
  2. The upcoming ice age has been postponed indefinitely
    What is the expected surface temperature change caused by the change of radiative forcing due to the maunder minimium? If you are saying that the change in radiative forcing is about 0.2 and given a change of 1 leads to a surface temperature change of ~0.6oC then are we looking at an estimated drop in temperature of 0.12oC. How did this ever manifest itself in any noticable change in the climate? It's the difference between 2005s climate and 2010s climate.
  3. The upcoming ice age has been postponed indefinitely
    Finally found the paper I referenced above (#25) "High-resolution Holocene climate record from Maxwell Bay, South Shetland Islands, Antarctica", K.T. Milliken, J.B. Anderson, J.S. Wellner, S.M. Bohaty, and P.L. Manley, GSA Bulletin, November/December 2009; V 121; no. 11/12; p 1711-1725; doi: 10.1130/B26478.1 From the abstract (as I have yet to read through the whole thing for a blog post): "After 2.6 ka, the climate varied slightly, causing only subtle variation in glacier grounding lines. There is no compelling evidence for a Little Ice Age readvance in Maxwell Bay. The current warming and associated glacial response in the northern Antarctic Peninsula appears to be unprecedented in its synchronicity and widespread impact." Not being a glacier expert, it'll take me some time to make heads or tails of this particular paper, but it looks like the authors are trying to determine if the current meltback on the Antarctic Peninsula has antecedents or not. Cool stuff.
  4. There's no empirical evidence
    What are peoples thoughts on Gerlich & Tscheuschner's paper "Falsification Of The Atmospheric CO2 Greenhouse Effects Within The Frame Of Physics"? http://arxiv.org/PS_cache/arxiv/pdf/0707/0707.1161v4.pdf A quick rundown can be found here: http://climaterealists.com/index.php?id=4992
  5. On the reliability of the U.S. Surface Temperature Record
    Tom @ 148 - ahhh yes, of course! 19C, thanx. So how does Menne get this bias to cooling? Thought I had figured it out..... Doug @ 149 - hmmm, yes I think I get it now, I was thinking too literally in Temperature, not thinking in energy gain/loss. note to self - temp is just a tool to help show energy changes as weight is for mass on earth! thanx again gents, will hopefully be better next time! PS - John, great site, full of respect and knowledge, you may get me off that lukewarm fence yet!
  6. On the reliability of the U.S. Surface Temperature Record
    It would appear that 'skeptics' believe every station shift or microsite issue leads to a warm bias. this must be why they never, ever report on individual stations that have a cooling bias due to various non-climatic changes. What they do is collect examples of (possible and actual) warm biased stations and generalise from there. What needs to be done, and what has not been done by the skeptics, is the quantitative analysis that would show whether this assumption has merit. That does not prevent conclusions being drawn from anecdotes, unfortunately. In the Watts post on Menne et al we learn that the quantitative analysis is finally going to be done in an upcoming paper, but Even Jones advises further down in the comments that it 'won't do' to simply use the raw data from good stations - that something must be dug out because "more is going on". It will be ironic if they end up 'adjusting' the data, considering the overriding memes at WUWT. I look forward to the quantification of the project undertaken by surfacestations. Though much of the carry on at WUWT is woeful, I maintain that the rating of USHCN by Watts and collaborators is a boon to climatology.
  7. Human CO2 is a tiny % of CO2 emissions
    Lord Monckton is quoted as saying that if every nation were to cut emissions by 30% over the next 10 years, "the warming forestalled would be 0.02 degrees celsius, at a cost of trillions". Is this true?
  8. Guest post in Guardian on microsite influences
    Yes, I did, but it's nice to have the pointer to the ncdc page ... is Menne 2010 the first paper to compare data from the new network with the old, historical weather station network? More important, has NOAA photographed all 100+ of the new stations, or not? If so, in color, or black-and-white? "John - I'm sure you are aware that the counter from Watts is that the reason that he wants a fuller sample than that used by Menne before writing it up is because the earliest returns of photos of sites were naturally urban - close to the neighbourhoods of volunteers." Researchers have previously compared rural with urban stations and have found no significant difference in trend.
  9. On the reliability of the U.S. Surface Temperature Record
    Leo G at 08:08 AM on 29 January, 2010 The artificially heated thermometer is going to be more or less at equilibrium with the cooler environment it sits in. If it were not able to attain that equilibrium it would not only be in violation of physics but it would continue warming forever, or at least until it burst into flames, melted or whatever. If the environment of the biased thermometer is warmed the equilibrium of the biased thermometer is disturbed, the upshot being that the biased thermometer will reflect changes in the ambient temperature of the greater space it occupies, even when the ambient temperature is still lower than the biased reading of the thermometer.
  10. On the reliability of the U.S. Surface Temperature Record
    Leo G, your third paragraph is incorrect because it has the thermometer acting as the thermostat for the central heater. Instead, put a separate thermostat somewhere else in the room and (somewhat unrealistically) so far away from the light bulb that the thermostat is completely unaffected by the light bulb. That results in the light bulb adding 1 degree to the thermometer, in addition to the ambient air's temperature. So when the ambient air temperature goes from 16 to 18, the thermometer also goes from 16 to 18, but then goes up an additional 1 due to the light bulb. The total is the thermometer reading 19, which is a rise of 2 from the starting value of 17. That is the same rise recorded by the thermometer in the room lacking the light bulb.
  11. Guest post in Guardian on microsite influences
    padruig, that was just mentioned by dhogaza.
  12. On the reliability of the U.S. Surface Temperature Record
    Doug @ 30 - "the lightbulb in the room" mind exercise. (Doug, may I change this a bit, and just for argument sake, I want the light to have a thick metal reflector on it to absorb some of the lights heat energy (yes I'm using an incandescent bulb!), so as to compare to an air field tarmac situation OK?) If the light bulb gets the sensor to read say 17C when the ambient room temp is 16C, then no anomaly will appear until the ambient room temp gets above 17C correct? Take another room also at 16C but no light bulb. With central heating, and both rooms were raised to 18C, then light bulb room would only show a 1C anomaly, whilst no light bulb room would show a 2C anomaly, correct? So though we know in fact that there is a true 2C anomaly, by averaging the two rooms anomalies we only get 1.5C so are thus under reporting by a full 1/2C. So is this what Menne is saying about a cooling bias? But wait, what if at night time, before going to bed, I turned the heat down in my house (again the rooms are at 16C, and sensor one reads 17C, sensor two 16C). Just for argument sake the rooms both loose 1/2C per hour and just for argument, the heat is lowered for 8 hours. Now the room with the sensor that has no light at the time the heat comes back on is reading 12C, but the sensor in the room with the light and heavy metal reflector is at about 13C (yes I grabbed this one out of thin air, but you get my point I hope). Now the combination of both rooms will show a bias towards warmth at about 1/2C. Of course this is a very simple thought experiment, but I hope you get my drift. Sightings really can make a difference. I don’t even want to try to think about a station getting the heat from an air conditioner during the day, then having a large temp drop during that clear starry night! I do not know if the bad sightings create a neg or pos on the anomaly, but it would be good to know in my opinion. Thanx for your time Doug.
  13. Guest post in Guardian on microsite influences
    I'm curious why these discussions fail to address the US Surface Climate Reference Network? An outgrowth of a study conducted in the late 1990's, the USCRN went online in 2003 to address some of the concern about site based bias in measurements. More information is available from NOAA. http://www.ncdc.noaa.gov/crn/
  14. The upcoming ice age has been postponed indefinitely
    I did read it and here is my response: - to attribute glacial periods to simply variations in the earth's orbit is somewhat simplistic given hat there are a lot of other parameters that affect whether glaciation occurs or not. Just having cooler temperatures is not enough - you also need precipitation in the form of snow such that accumulation exceeds melting. In addition to orbital variation, ocean currents and solar & cosmic radiation all factor into the equation.
  15. On the reliability of the U.S. Surface Temperature Record
    In all of the explanations of the trend correlations described between the CRN 1 and 2 vs the CRN 3/4/5 sites, is there an implicit finding that there is a constant bias for a given site and that there is not a stochastic error term which is higher for the CRN 5 vs CRN 1 sites?
  16. Guest post in Guardian on microsite influences
    Alexandre, your reasoning is correct. That and related issues are discussed in the post and comments in the other thread--the one having John's original post, On the reliability of the US Surface Temperature Record.
  17. On the reliability of the U.S. Surface Temperature Record
    trrll @ 79 - Watts and Pielke Snr. are working on a paper. Should be interesting to see what they come up with with double the stations to work with
  18. Guest post in Guardian on microsite influences
    John Congrats on your Guardian article. I think it is an excellent contribution. You also say "Anyway, it's weird excerpting my own writing" to which I reply, when referencing, always reference the best. John
  19. Guest post in Guardian on microsite influences
    Mark J @ 15 - re: Watts?Pielke awaited paper, and so science goes, building, or tearing down, based upon past papers. Seems to work not bad eh?
  20. Guest post in Guardian on microsite influences
    Thanks dhogaza for that clarification. Sounds good.
  21. Guest post in Guardian on microsite influences
    John - I'm sure you are aware that the counter from Watts is that the reason that he wants a fuller sample than that used by Menne before writing it up is because the earliest returns of photos of sites were naturally urban - close to the neighbourhoods of volunteers. I think it is arguable that he and Pielke Snr will get a strikingly different result when they get their turn to use their siting scores with temp data. I guess you didn't mention that because you think it is a weak argument by Watts? I don't think we will have too long to wait to find out.
  22. Guest post in Guardian on microsite influences
    RSVP ... "If a pristine mountain peak in the middle of the Pacific makes sense for monitoring CO2, why not apply similar rigor for weather stations? Instead of trying to salvage this data, maybe better to start from scratch. Dont we have 100 years or so to work on this problem? Much cheaper in the end too." Well, actually, a new temperature monitoring system, designed from the ground up to meet climatology needs, has not only been designed, but deployed. It's called the US Climate Reference Network. In fact, it's the CRN siting criteria that Anthony Watts is using to "prove" that certain stations in the Historical Climate Network are "bad" - using standards set in the last decade to categorize stations that are decades or a hundred years old. One of the results of the Menne 2010 paper is that the several years of USCRN data we have matches the temperatures derived from the historical stations extremely closely. Two separate sets of stations, one set explicitly designed to meet rigorous siting standards and provide optimal spatial coverage. The other a much larger set of stations placed originally to provide data for weather forecasting. And they match. And as years go on and they continue to match, it will only increase the confidence of the accuracy of data from the historical network of stations (though within science it's already sky-high). The historical data has been subject to dozens of tests, and has always passed with flying colors. The only test it hasn't passed is the "I took a photo but did no analysis" test, which is bogus. Not only do we not have 100 years to wait, there's no reason in the world to throw out existing, perfectly good, data - except for the politics of delayed action.
  23. Guest post in Guardian on microsite influences
    There's one thing in this subject that strikes me as obvious, but I haven't seen it so far (not that I've searched much): We're not talking about absolute temperatures, but instead they're temperature *anomalies*. If I had a termometer in an oven at 200ºC for the whole century, the anomaly would be zero. So having a termometer in a parking lot, while it yields of course a higher temperature, it does not produce increasingly higher temperatures over the years and decades. Am I oversimplifying it?
  24. Guest post in Guardian on microsite influences
    Good article John. My view of why the denialists are gaining grounds is that they don't use solid arguments in their argumentation. They make it easy for people to follow their line of "logic". Pictures of "bad" sited temperature instruments seems to do the trick in many peoples mind. We know that the arguments of the denialists are simple, so thats why it's easy for general public to follow their kind of "logic". In the sametime the science is not as easy to follow and easy to misunderstand. But instead of trying to stay ground and defend the science, I thing the science should be made easier to follow. The only way, in my opinion, to manage that is to make an offensive, where you make it your goal to make climate science understandable for the general public. We still haven't achieved that goal, or maybe we still haven't set that goal... One reason for that, is that the climate science are complicated. But I thing that it's an achievable goal with the right means. I'm not an activist, but I think that by simplifying (in words) the science somehow we're half way there. This should not be the scientists job, and in many cases I don't think that it always lies in their skills to make a simple argument ;) They should be able to continue their work. But in some way I know that this is an achievable goal, with the right means. Regards, Svatli
  25. On the reliability of the U.S. Surface Temperature Record
    JPark, I have a question for you. Why are you having such a hard time understanding the findings of Mennes et al, despite the science being explained to you over and over? I do not sensing a sincere desire to learn on your part, but rather any opportunity to taunt and to obfuscate. Additionally, when posters here have provided very good arguments or explanations (which has been often), your retort has sometimes been to post yet another post from a political blog (WUWT). You seem to accept Anthony's pontification without question or critique. Why is that? I have a hypothesis, every time you close your eyes, you see Anthony's images of a station near a parking lot. If so, then you really do need to move beyond that. Someone called you a skeptic the other day, actually you are displaying traits of someone in denial about AGW, or those of a contrarian; rest assured, your actions show you to definitely not be a true skeptic. I'm hoping if you had a heart problem you would take the advice of the cardiologist and not that of say, your uncle Ben, who seems to be omniscient and very convincing at the dinner table with his anecdotes, but when his claims are checked out, most times they tend to be wrong. Watts by the way, is "uncle Ben".
  26. On the reliability of the U.S. Surface Temperature Record
    Jpark, talking of being "behind the curve", have you found the values of the long term trends in global temperatures from the RSS, RATPAC, GISStemp, CRU and NCDC data yet? Do you know why I keep insisting that you look at the long term trends in those global temperature data sets?
  27. Berényi Péter at 03:44 AM on 29 January 2010
    Peer reviewed impacts of global warming
    You can defuse the population bomb through restriction of carbon based energy usage only by generating artificial famines. Is that what you want? I propose building & maintaining schools, training & paying teachers, educating girls worldwide. In several decades you'll have quite different problems with an overaged declining world population (as Europe and Japan already have). But it is another story.
  28. Berényi Péter at 03:22 AM on 29 January 2010
    Predicting future sea level rise
    Satellite sea level data are valuable in determining short time and/or regional changes, but they are absolutely infeasible to draw secular trends because of orbital drift. The problem is overcome by calibrating satellite measurements against tide gauges (just sixty four of them). The moral of the story is that sea level trends measured by satellites are not better than those measured by a few gauges at unspecified locations. http://sealevel.colorado.edu/ On the other hand, gauge data are of course measured relative to shore elevation which is also subject to regional change. Crustal segments have different and considerable vertical movement relative to both eachother and sea level. It is easy to see that the more gauges are used, the smaller the error gets. However, satellites are only calibrated against a restricted set. I could not find documentation about geographic distribution of tide gauges used in calibration at the UCB site. Reliable GPS calibration is not done yet, although it is said to be in the pipeline.
  29. Guest post in Guardian on microsite influences
    Good article. I'm glad the Guardian still publishes reasoned analysis. While I felt it was a fairly intuitive and complete discussion, I'm not sure it's going to satisfy the "photos don't lie" crowd who don't have the time, skill, or inclination to verify the study's conclusions for themselves. Their argument might be "how can we trust any 'analysis' when those photos clearly show urban or microsite warming influences...this just proves it's a scam." Addressing the photo argument more directly would be good - perhaps an intuitive explanation as to why such stations do not add an overall warming bias to the U.S. trend. The recent AMS USHCN version 2 study usefully addresses the Surface Stations argument. RSVP: "The continental US doesnt exactly seem like the best location on Earth for monitoring global warming." Tell that to the "global warming is a scam" crowd, who have been using relatively cooler U.S. temperatures over the last year or two to argue against global warming. Mr. Watts is a full participant in this line of spin. The U.S. surface record is unreliable, except during the times it shows cooler temperatures.
  30. The upcoming ice age has been postponed indefinitely
    Hi Tom. (#31) You may or may not be right. What Professor Plimmer says about climate does not stop him being an eminent geologist though! His academic qualifications and awards look pretty impressive.
    Response: Ian Plimer is a qualified scientist, which makes the statements he makes all the more baffling. Having read his book and listened to his interviews, I've heard him make the following statements: Most perplexing for me is that he continues to repeat these falsehoods after his errors have been pointed out to him, with utmost confidence and contempt for, well, nearly every climate scientist in the world. I see him debate Barry Brook live this afternoon in Brisbane so maybe I'll gain more an insight then.
  31. On the reliability of the U.S. Surface Temperature Record
    A good rebuttal to D'Aleo and Watts is provided by John Nielsen-Gammon (Prof. of Meteorology at Texas A&M U., and Texas State Climatologist). But that portion of that blog post doesn't start until about one third of the way down; look for the paragraph that starts "Meanwhile," or Find "Watts." Includes a numerical example.
  32. The upcoming ice age has been postponed indefinitely
    Ubique, Ian Plimer is a poor choice to hold up as an "eminent geologist." His opinions on climate are complete nonsense--not just wrong, but really far, far off. Just one of many places you can find detailed rebuttals to his claims is Deltoid.
  33. Guest post in Guardian on microsite influences
    John - thanks for the response - the NOAA article was the reference I was looking for. I'm just curious - WUWT seems to have devolved into just a load of total nonsense that is obviously nonsense. ClimateAudit.org seems to still have an air of "trying to be somewhat scientific" (when you weed through all the FOIA and BS email analysis) - I'd love to see a more through take-down of his analytical posts....anything in the works there or just too much work for too little benefit?
  34. The upcoming ice age has been postponed indefinitely
    NewYorkJ(#28 Thank you for that. I am neither a convinced sceptic nor alarmist - just an average guy trying to make sense of all this stuff as I have a professional interest in the application of this science. But it seems that one cannot be neutral in this debate - so at the moment I must err on the sceptic side as I am still asking questions and trying to keep an OPEN mind rather than trying to BROADEN it as John suggested rather tartly in his response to my post. I was thinking of Professor Ian Plimmer when I said eminent geologists, not the author of Geocraft who I would not know from Adam - apologies if I implied the latter. As a result of "Climategate" I am not sure whose information to trust - along with a great many other people on the edge of this issue I would imagine!
  35. Guest post in Guardian on microsite influences
    Congratulations, John. I very much liked your article, sounds very natural and it's easy to follow, well fitted to the general audience. It highlights the recurrent skeptical strateggy of arguing with insinuations instead of with actual analysis. It's much quicker and they can produce many more (flawed) arguments, while real scientists spend their time in the (much more time-demanding) real analysis (to be published once the flawed conclussion has already spread out). This is the standard style of Climate Audit, for example. As Winston Churchill said, ‘A lie gets halfway around the world before the truth has a chance to get its pants on’. People must learn to discern what the real scope and implications of a discovery is. Eg. "I discovered a handful of trees crowded together in northern Siberia with a divergence problem". Does it prove that all reconstructions of global temperature over the past 1,000 years are wrong? You don't need a leading scientist doing the hard work to know that insinuations don't prove anyting. Exactly the same with poorly-sited weather stations and Anthony Watts' gratuitous insinuations.
  36. Guest post in Guardian on microsite influences
    Oh get real RSVP, do you honestly think that our researchers are so thick that they haven't considered everything you've mentioned, & account for it in their calculations? What is of concern is the warming which has occurred in the last 60 years, which has been measured by suitably reliable measuring stations. Seriously, I really don't know why you're so keen to make excuses for the "head-in-the-sand" approach taken by the Denialist Cult.
  37. Guest post in Guardian on microsite influences
    RSVP, if its winter where you are, then why are you surprised that the temperature is -7 degrees? Here in Australia most of the country has had temperatures at least +2 to +3 degrees C above average for the last 3 months (Adelaide temperatures for November were more than 5 degrees above average), & AMSU-A shows global January 2009 temperatures to be more than +0.2 degrees above those of 2009-your little corner of the world clearly doesn't represent the world entire. Also, I don't believe we have 100 years to fix the problem. Satellite & surface temperatures are in agreement-+0.16 degrees per decade since 1979. As we don't know for certain just how had the impacts of future rises are going to be, I think it would be irresponsible to wait 100 years to "double check". If we don't take serious action within the next 20-30 years, I believe it will be too late to avert a truly catastrophic rise in temperatures. The fact is that, had we listened to the scientists 20 years ago, instead of letting the fossil fuel industry have its way, CO2 mitigation would have been a *hell* of a lot cheaper!
  38. Guest post in Guardian on microsite influences
    yocta This is taken from the site "Temporal Representativeness In addition to difficulties with the correct exposure of instruments, thought has to be given to changes in the long-term exposure of the site. Buildings in close proximity to the instrument enclosure will result in the area of representativeness being reduced. For example, when the instrument enclosure at Sydney was installed in 1788, the instruments were representative of a relatively wide area around Sydney. With subsequent construction of high-rise buildings and freeways, climatic and meteorological conditions only 50m from the site are now significantly different to those at the site. It is important that the station be inspected regularly and any changes in the siting are properly documented." 1788? Aside from the site, what about technology? Was there even a universal standard set of measurements in 1788? I must be going nuts, or is it the CO2?
  39. On the reliability of the U.S. Surface Temperature Record
    HumanityRules, the use of the raw readings of a station to construct a long time serie is a myth, too many things change with time. Indeed, making a reliable time serie is the most difficult part and a lot of effort has been put to make the raw reading reliable over time. There is no way to extract usefull climatic information from raw data. You can get some general idea of the process from the NCDC itself; no mistery, no hiding.
  40. On the reliability of the U.S. Surface Temperature Record
    Update 28/1/10 John could you explain homogenization and interpolation and their relation to raw and adjusted data. because it seems what Watts is complaining about is the interpolation process which he call homogenization. I think!
    Response: Interpolation and homogenization are two different things. The strict definition of interpolation is filling in the gaps between data (as opposed to extrapolation which is extending beyond your data). In the case of surface temperature, it's been observed that there is strong correlation of temperature anomaly between adjacent regions so interpolation into regions where no measurements have been taken can be done with some degree of confidence.

    This is also somewhat related to geospatial averaging - Tom Dayton posted a good explanation of that here... 

    Homogenization is the process of adjusting the data to remove spurious biases. For example, moving a weather station to a different location, changing the instrument that measures temperature or changing the time of day that the measurements are taken can all impose warming or cooling biases on temperature readings.
  41. Guest post in Guardian on microsite influences
    The Australian Bureau of Meteorology has a nice little page of the requirements for Australia's Automatic Weather Stations , with details including where they are and site requirements. The site lists exactly the things a trained metrologist needs to consider when seeting up any decent temperature monitoring system: Resolution, Repeatability, Response time, Drift, Hysteresis, and Linearity. It is interesting that in all of this that Watts and the WUWT members seem to forget that America is actually not the world. Australia is of pretty comparable surface area wise to America and if the stations here report a similar warming trend... I wait with keen eyes for Watts full analysis!
  42. Guest post in Guardian on microsite influences
    It is -7C, 9:10 in the morning (daylight "savings"), not a cloud in any direction, the sun shining bright and beautifully. I am suppose believe it is warmer than it should be. "Please Sun, do your thing." The thought of hundreds of bogus weather stations occupies me after seeing this theme now repeated. It would be nice to know what the measurement accuracy of these systems have on their own. If, for instance, the Earth's temperature was actually rising 0.10 degree per decade, you would need at least +-.05 degrees to even begin to substantial this. And I am not talking about termocouple specs or a thermometer's rating. I am talking about the system as a whole (its total accuracy), and how it is set up. (The graphs of figure 2 in the original article were plotting values to within a tenth of a degree, which implies an accuracy of +-.05. Spectacular, but real?) If a pristine mountain peak in the middle of the Pacific makes sense for monitoring CO2, why not apply similar rigor for weather stations? Instead of trying to salvage this data, maybe better to start from scratch. Dont we have 100 years or so to work on this problem? Much cheaper in the end too. Aside from issues of accuracy, another important system parameter is repeatability. Repeatibility that can be guaranteed over many years. If you were to simply take the sum of measurements over time from a set of reliable and repeatable instruments, (even if every sensor was buried in a 1 meter cube of cement), this global checksum would tell you something about global warming, because it is the relative change that matters, not the absolute temperature reading. My last remark. The continental US doesnt exactly seem like the best location on Earth for monitoring global warming.
  43. On the reliability of the U.S. Surface Temperature Record
    doug_bostrom at 17:07 PM on 27 January, 2010 doug, while being a scientist, it's not really the science of climate change I'm interested in, it's the politics. So no I haven't been clinging to any ideas for years. I keep coming back to John's website because I find it challenging and I try to critically appraise it for that reason. The reason I asked those question. Maybe summed up as is instrument change the only real factor in microsite issues of stations because come the adjustment process there appears to be multiple points at which data is adjusted. The following image is a site that got alot of coverage on skeptic sites, it's Darwin Airport, Australia. http://www.estatevaults.com/bol/_graph_cru-darwin7.jpg While there is a big jump in 1940 (maybe location change) there are also many small, positive changes from 1940-1980 giving an apparent trend. What is the justification for these if the Menne 2010 paper has ruled out almost all influence from microsite changes?
  44. Guest post in Guardian on microsite influences
    Congratulations, very prestigious.
  45. Guest post in Guardian on microsite influences
    John - I remember reading about a construction of the temperature record using only the sites that WUWT considered "good" - and the conclusion was that the record lined up perfectly with other records. Do you happen to remember the article or have a link?
    Response: I'm just going from memory here so anyone chime in if I get the details slightly wrong. Early in the history of the surfacestations.org project, one of the users John V took the existing ratings and compared the temperature trend from the best weather stations (rating 1 and 2) to the GISS temperature record. The expectation was that the GISS temp would show a warmer trend as it included all those poorly sited stations besetted with microsite influences. Instead, John V found the good weather stations showed a near identical trend:

    Surfacestations.org GISS Temp vs Ratings 1 and 2 weather stations

    While this result was initially met with dismay, Watts rallied and criticised the result, saying it was made with only a small percentage of stations being rated. I believe some time after this, Anthony Watts made the data on station ratings unavailable to prevent any other data analyses comparing good and bad weather stations - but I'm not sure of the timing of this.

    The next analysis was by NOAA who also published an analysis comparing only the good stations to the total record (NOAA 2009):



    Again, the trends are near identical (you expect some discrepancy as both records cover slightly different regions). Watts criticised this result as a result of homogenisation (data adjustment) of both the good data and the full dataset. That's why Menne 2010 is interesting in that it uses unadjusted data - this is where the cooling bias is revealed.
  46. On the reliability of the U.S. Surface Temperature Record
    ... I am behind the curve as ever ;-)
  47. On the reliability of the U.S. Surface Temperature Record
    Maybe not yet... quote: I realize all of this isn’t a complete rebuttal to Menne et al 2010, but I want to save that option for more detail for the possibility of placing a comment in The Journal of Geophysical Research. When our paper with the most current data is completed (and hopefully accepted in a journal), we’ll let peer reviewed science do the comparison on data and methods, and we’ll see how it works out. Could I be wrong? I’m prepared for that possibility. But everything I’ve seen so far tells me I’m on the right track.
  48. On the reliability of the U.S. Surface Temperature Record
    Helpful? http://wattsupwiththat.com/2010/01/27/rumours-of-my-death-have-been-greatly-exaggerated/
    Response: Already updated the article above responding to Watt's latest post, which is a little disappointing but understandable if he's saving his best material for peer review.
  49. Guest post in Guardian on microsite influences
    John, excellent job. Thanks for agreeing to do the article. Education on the science behind climate change is key to helping the general public come to terms with what is happening with AGW and what is expected to happen as AGW ramps up in coming decades. I hope that they ask you back to speak to other issues, and that you accept. I've being trying to encourage the editor of one of our provincial newspapers to have a regular column for the purpose of educating the public on climate science and meteorology but to no avail.
  50. On the reliability of the U.S. Surface Temperature Record
    sbarron2000 asked "I think this is a lot of geospatial averaging of the monthly anomalies and the mean anomaly which goes on prior to actually making our comparisons of temperature anomalies, right? Why was this done? What is the effect of doing it? Would the results be different if you didn't? "Gridding," as geospatial averaging is called, is not just useful. It is essential because we are trying to measure the temperature of the Earth, not of the thermometers. The thermometer manufacturer might be interested in the thermometers themselves in order to assess, oh, say manufacturing quality, so the manufacturer might not care where the thermometers are located. But we use thermometers only as a means to measure the temperature of the Earth's surface. Measuring the temperature of the Earth's surface requires taking a representative sample of the Earth's surface. We do that by dividing the surface into equal sized grid squares and finding a single temperature for each grid square. Then we average all those. The result is an average temperature that equally weights every grid square. In contrast, if we simply averaged all the thermometers regardless of their location, we would have an unrepresentative sample of the Earth's surface. Imagine that on the entire Earth we had only 1,001 thermometers--1,000 in Death Valley but only one at the North Pole. If we simply averaged all 1,001 thermometers' temperatures, the resulting single temperature would be a gross overestimate of the Earth's temperature. It would be nice if our thermometers happened to be distributed completely evenly, because then we could take the shortcut of simply averaging all the thermometers. But in reality, thermometers are very nonuniformly distributed. So we must gather a representative sample of the Earth's surface by computing only a single temperature for each grid square. If one particular grid square happens to have 10 thermometers and another grid square happens to have only 1, then that first grid square's temperature (the average of those 10) probably will be a better estimate of that square's "true" temperature. But its estimate will not be biased in any direction, compared to the square having only a single thermometer.

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