Phil Jones and the China Network: Part 1

Muir Russell told the Sci Tech Committee that the Muir Russell panel “fully investigated” the allegations about the Chinese network of Jones et al 1990. This was totally untrue. Not only did Muir Russell panel fail to “fully” investigate, as was the case on too many other issues, Muir Russell didn’t investigate at all.

In today’s post, I’m going to start a long backstory to this dispute – much longer than I anticipated when I started summarizing Muir Russell’s testimony at the committee. It will take about 4-5 posts in all (based on what I’ve written so far.) I found the narrative quite intriguing to reconstruct, though, at times, the affair seemed as though the characters from Burn After Reading (the Coen Brothers’ movie) had been transplanted into academia.

Here’s a quick synopsis. The overarching issue in the Chinese network controversy is whether the development of urban heat islands in the 20th century had a significant impact on land temperature indices such as CTUTEM and GISS. Jones et al 1990’s importance in this argument was its conclusion that the contribution of urbanization to 20th century trends was negligible (no more than ~0.05 deg from 1900-1990.) It was cited as authority for this claim in both IPCC TAR (2001) and AR4(2007), along with a couple of other articles by closely allied authors (Peterson, Parker). The Chinese network of Jones et al 1990 was one of the main props: Jones purported to demonstrate the unimportance of the urbanization contribution by showing that there was a negligible difference in temperature trends between urban and rural sites in China between 1954-1983.

Jones et al 1990 had bothered Warwick Hughes a long time ago. After its continued citation in AR4, I re-considered it at CA in February 2007, reporting apparent inconsistencies between quality control said to have been done by the authors of Jones et al 1990 and the non-existence of the station histories required for the quality control reported in contemporary technical documents. This led to my first climate FOI – successful by the way. By April 2007, I had satisfied myself that, whatever the actual contribution of urbanization to temperature trend, Jones’ analysis of the Chinese data was worthless and didn’t pursue the matter. However, as CA readers know, Doug Keenan did pursue the matter, arguing that that the incident rose to research “fraud”. (Such allegations were not made here, since as CA readers know, I don’t find “fraud” a useful way to frame issues in climate science and have blog policies against such allegations. ) The issue as framed by Keenan took on a life of its own.

Urban Heat Island Effect and IPCC
Anyone who lives in a large city understands the “urban heat island” effect. The difference in temperature between cities and rural areas can be readily measured by high school students. The concept was entered into academic literature at least as early as Oke (1976), who proposed a rule of thumb that the magnitude of the effect was proportional to the log of the population. (A corollary of this, not commented on in the climate science literature, is that urbanization can contribute to the trend in towns as well as cities.)

Although it seems logical that the development of cities would have an impact on temperatures and contribute in some measure to the overall 20th century land temperature trend, an important item in the IPCC consensus is that it doesn’t. (This counters a standard “skeptic” issue.) IPCC TAR (2001) Box 2.1 asserted:

Extensive tests have shown that the urban heat island effects are no more than about 0.05°C up to 1990 in the global temperature records used in this chapter to depict climate change.

In the running text, Jones et al 1990, together with one other study, was offered as authority for this claim:

These results confirm the conclusions of Jones et al. (1990) and Easterling et al. (1997) that urban effects on 20th century globally and hemispherically averaged land air temperature time-series do not exceed about 0.05°C over the period 1900 to 1990 (assumed here to represent one standard error in the assessed non-urban trends).

IPCC AR4 (2007) in the relevant chapter (edited by CLAs Jones and Trenberth) continued to rely on Jones et al 1990 as authority against the existence of a UHI effect:

Studies that have looked at hemispheric and global scales conclude that any urban-related trend is an order of magnitude smaller than decadal and longer time-scale trends evident in the series (e.g., Jones et al., 1990; Peterson et al., 1999).

Thus, while Jones et al 1990 may be a relatively old study, it continues in use as a cornerstone study contesting a hot-button issue (UHI).

Back to the beginning.

In 1988, the US and China entered into an agreement for the exchange of climate data. (See Koomanoff et al, BAMS, 1988). The exchange led to Technical Report NDP039 published in 1991 by Tao Shiyan, Fu Congbin, Zeng Zhaomei and Zhang Qingyun of the Institute of Atmospheric Physics, Chinese Academy of Sciences in Beijing, China. This report described two networks – a 60-station network for which station histories were available and a 205-station network for which station histories were unavailable.

Unfortunately, station histories are not currently available for any of the stations in the 205-station network; therefore, details regarding instrumentation, collection methods, changes in station location or observing times, and official data sources are not known.

NDP039 expressed caveats about the homogeneity of the network:

Few station records included in the PRC data sets can be considered truly homogeneous. Even the best stations were subject to minor relocations or changes in observing times, and many have undoubtedly experienced large increases in urbanization. Fortunately, for 59 of the stations in the 65-station network, station histories (see Table 1) are available to assist in proper interpretation of trends or jumps in the data; however, station histories for the 205-station network are not available. In addition, examination of the data from the 65-station data set has uncovered evidence of several undocumented station moves (Sects. 6 and 10).

During the course of this exchange, Zhaomei Zeng visited the US as a visiting scholar at SUNY, where her host was Wei-Chyung Wang. While NDP039 explicitly asserted the non-existence of station histories for the 205-station network, Wang’s evidence in 2007-8 was that the station histories did exist at the time in paper form:

Digitization of the hard copies of “station histories” was prepared in 1989-90 by Ms. Zhao-Mei Zeng (IAP/CAS) only for the 60-station network, while the “station histories” of other stations, including those we used in 1990 urban warming study, were available in paper form,

Despite much publicity and three inquiries into this and related matters, no one has shown that the station histories did exist. Indeed, the UK inquiries didn’t even ask.

Jones et al 1990
In 1988, Tom Karl had published a study purporting to show that UHI didn’t “matter” in the US. In 1990, Jones decided to extend the results to the rest of the world and sought out data for networks in Russia, Australia and China in order to compare “urban” and “rural” sites as a supposed way of estimating the urbanization impact on global temperature. They concluded that there was “no indication of significant urban influence” in any of the three networks and that an upper limit of ~0.05 deg could be set on the contribution of urbanization to 20th century land temperatures, an order of magnitude less than observed warming.

Jones had obtained the Chinese data for this network from W-C Wang in the US in 1989 or early 1990. The data had been collated by Zeng, a visiting scholar at SUNY in 1990, who had collated an 84-station subset from NDP039 data, consisting of 42 pairs of “urban” and “rural” sites. Wang and Thomas Karl of NOAA were recognized as coauthors of Jones et al 1990, while Zeng was neither listed as a coauthor nor even acknowledged. The collation of the Chinese network was described as follows:

We assembled a network of 42 station pairs of rural and urban sites in the eastern half of China. The data cover the period 1954-83. The 84 stations were selected from a 260-station temperature set recently compiled under the US Department of Energy and People’s Republic of China Academy of Sciences Joint Project on the Greenhouse Effect. The stations were selected on the basis of station history: we chose those with few, if any, changes in instrumentation, location or observation times. All 84 records were complete for the 30-year period. The urban stations were in regions with populations of over 0.5 million whereas for the rural stations populations mostly less than 0.1 million (according to 1984 population figures).

While most subsequent attention had focused on station histories, the claim that the coauthors of Jones et al 1990 had assembled the network was untrue: in fact, they had appropriated Zeng’s data (Zeng neither a coauthor nor acknowledged).

Wang et al 1990
A few months later (December 1990), Zeng did appear as a coauthor in a less prestigious journal (GRL), publishing “Urban Heat Islands in China” together with Wang and Tom Karl (both coauthors of Jones et al.) The network was described in virtually identical terms (and was identical):

The temperature data used in this study are based on 42 pairs of urban-rural stations from from a 260-station temperature set recently compiled under the United States’ Department of Energy and People’s Republic of China Academy of Sciences joint research project on the Greenhouse Effect. (Koomanoff et al 1988). The temperatures cover the period up to 1983. ..These stations primarily cover the eastern part of China. They were chosen based on station histories: selected stations have relatively few, if any, changes in instrumentation, location or observation times over this period … most stations with populations of over one million for urban sites (average 1.71 million) and less than 0.2 million for the rural sites (average 0.147 million)…

The ruralness of the “rural” sites is somewhat gilded in Jones et al 1990, which stated the stations were “mostly” under 100,000 while Wang et al 1990 said that they were actually mostly under 200,000 (average 147,000). Wang et al 1990 cited Jones et al 1990 (but not vice versa), making the following odd observation (given the commonality of two coauthors):

Our work differs from the recent study by Jones et al 1990. They have shown that any urban bias in their data has been mitigated over Eastern China. The reasons for this are not clear.

Warwick Hughes was a determined advocate that the land temperature indices had under-estimated UHI contribution and was a particular critic of Jones et al 1990. but was highly dubious, to say the least, that Jones’ “rural” network in China was actually rural.

We are trying to identify these 84 stations in order to verify the Jones et al. claims, but it is obvious that a station with a population of anywhere near 100,000 can hardly provide a “rural” benchmark.

See also here here.

Hughes, of course, was the recipient of Jones’ notorious email: “Why should I make my data available to you when your only objective is to find something wrong with it?” Hughes’ frustration at Jones’ stonewalling is evident in his posts on Jones et al 1990.

Oddly, Jones et al 1990 was one of my original questions when I became interested in climate science. In 2002, I emailed Jones inquiring about the data; Jones said that the data was on a diskette somewhere and it would take too much time to track down. I was then new to ways of the Team and didn’t pursue the matter.

Continue to Part 2.

Jones, P. D., P. Y. Groisman, M. Coughlan, N. Plummer, W. C. Wang, and T. R. Karl. 1990. Assessment of urbanization effects in time series of surface air temperature over land. Nature 347, no. 6289: 169-172.
Wang, W. C., Z. Zeng, and T. R. Karl. 1990. Urban heat islands in China. Geophysical Research Letters 17, no. 12: 2377-2380.


  1. David Jay
    Posted Nov 3, 2010 at 4:52 PM | Permalink

    Alright – another McIntyre Mystery! In 5 installments!

    I’m ready, scare me (apologies to Bill Cosby’s “Chicken Heart”)


  2. UC
    Posted Nov 3, 2010 at 4:57 PM | Permalink

    [Jones et al., 1990] – [Folland et al., 2001] – [Brohan et al., 2006] …

  3. Craig Loehle
    Posted Nov 3, 2010 at 4:58 PM | Permalink

    I assume you will be commenting in later parts about the updated analysis:
    Jones, P.D., D.H. Lister, and Q. Li (2008), Urbanization effects in large-scale temperature records, with an emphasis on China, J. Geophys. Res., 113, D16122, doi:10.1029/2008JD009916.

    which does conclude that UHI has an effect on trends.

    Steve: yep.

  4. Gary
    Posted Nov 3, 2010 at 5:04 PM | Permalink

    Have you discovered who held the station histories that were “in paper form?” Are they originals in Chinese, copies, or translated/transcribed into English forms? The provenance may be interesting.

    Steve: stay tuned. However, to my knowledge, no one knows at present whether they exist nor did either of the UK “inquiries” inquire.

  5. Rob R
    Posted Nov 3, 2010 at 5:07 PM | Permalink

    If the UHI effect is logorithmic with population, as also recently demonstrated by Roy Spencer, then it is little wonder Jones et al could get away with claiming UHI is insignificant. Most of the effect has accumulated before a population centre reaches a total of 50,000. So it looks like the Chinese “rural” network is itself largely urban in relation to the generation of this heat.

    Steve: again, wait for the story. However, the original Jones et al 1990 analysis of their China network was worthless.

  6. Sam the Skeptic
    Posted Nov 3, 2010 at 5:26 PM | Permalink

    By coincidence, about half-an-hour before reading this I came across the following quote in — of all places — ‘The Gardening Year’, published in 1968 by good old Readers Digest.
    In a note about the lowest temperatures of the year it says: “Gardens in large towns or cities are often several degrees warmer than in open country”.
    I appreciate this is not peer-reviewed research (!) but it is quite clear from the context that the urban heat island was a recognised concept as far back as the late 60s and every gardener I know has been well aware of it for most of my lifetime. Certainly the author didn’t see any need to make a big thing about this; it was simply a fact generally known and generally accepted.
    The surprising thing is that no-one challenged Jones et al (1990) at the time, or perhaps climatologists don’t have time to garden. Their loss!

    • KnR
      Posted Nov 3, 2010 at 6:43 PM | Permalink

      Sam the Skeptic that is because at the time no one cared , Jones worked in an area which was an offshoot of an offshoot, it had virtual no scientific importance and no public impact. So a small groups whose actions no was interested in could get away with quite a bit. It’s ironic that in courting public exposure Jones and co have brought public attention to their work which in turn created some of the problems then are now faced with.

    • Bernie
      Posted Nov 3, 2010 at 10:28 PM | Permalink

      It is important to remember with UHI that you have to identify a trend in the UHI effect and not simply that it exists in an absolute form. In other words as a particular city grows in population from 100K to 200K (or increases in its consumption of energy, increases in its generation of heat, increases the area of asphalt and concrete, or decreases in trees and grassy open spaces) the temperature metrics (average, min, max)increase due to increased urbanization.

    • TerryS
      Posted Nov 4, 2010 at 3:37 AM | Permalink

      The BBC are also aware of this. I have heard them say, in more than one forecast, things like “temperatures will be as low as -5 in rural areas, -3 in towns and cities”.

      A difference of 2C.

      • Phillip Bratby
        Posted Nov 4, 2010 at 1:45 PM | Permalink

        Terry, The BBC often say it’s 4C hotter in London than surrounding areas.

  7. GolfCharley
    Posted Nov 3, 2010 at 6:38 PM | Permalink

    @Sam the Skeptic
    I agree. I am sure that at school in the late 70’s UK, I “knew” that London was normally 2-3 degrees warmer than surrounding rural areas.

    Presumably the term Urban Heat Island was coined by Climate Scientists in the 80’s

  8. ThinkingScientist
    Posted Nov 3, 2010 at 6:39 PM | Permalink

    Further to Sam the Skeptic’s comment, it is quite clear during BBC weather forecasts (provided by the Met Office) that they often emphasise that the overnight low temperatures they give on the forecast charts are for cities and urban areas and that the overnight lows may result in more severe frosts in rural areas.

    If the effect is so small it would not merit comment on weather forecasts, surely.

  9. Robuk
    Posted Nov 3, 2010 at 6:39 PM | Permalink

    Sam the Skeptic said,
    Posted Nov 3, 2010 at 5:26 PM | Permalink | Reply

    By coincidence, about half-an-hour before reading this I came across the following quote in — of all places — ‘The Gardening Year’, published in 1968 by good old Readers Digest.
    In a note about the lowest temperatures of the year it says: “Gardens in large towns or cities are often several degrees warmer than in open country”.

    Our TV weather person states that mosts nights, 0.05 degrees is total rubbish and Jones et al know it, how long will this utter crap continue.

  10. Peter Dunford
    Posted Nov 3, 2010 at 6:40 PM | Permalink

    I can’t help but wonder who the peer reviewers were for Jones et al 1990 and why it wasn’t pulled up for contradicting the bloody obvious. We had thermometers in loads of cars then, telling us what the outside air temperature was. The “research” findings were counter-intuitive. By 1997 there was no excuse. Even the dyed-in-the-wool warmists at the Met-office and the BBC weather centres admit today (on air), that the temperatures reported for towns and cities will be a bit lower in the countryside. (Haven’t they even heard of Jones et al 1990?). These differences are several times the reported warming over the instrumental period. it is obviously absurd to suggest that back in the 80’s like minded souls might have started to put together the… never mind.

  11. Doug in Seattle
    Posted Nov 3, 2010 at 7:47 PM | Permalink

    Glad to see Steve back in form.

  12. Ed Snack
    Posted Nov 3, 2010 at 8:00 PM | Permalink

    There are papers from Torok and Torok & Morris (see Warwick Hughes site for some links) on UHI in Australia. They conclude that UHI does scale roughly with log population, and that the effect is noticeable around centres with populations as low as 1-2,000. In one of the papers as I recall they also found that the relationship did seem to vary in different countries, for example it was significantly higher per head in the USA compared to Australia.

    The studies are static studies of UHI, that is the effect is not analysed over time but only over distance. Thus they are not direct evidence of UHI in the temperature records. However they do very strongly suggest that UHI should vary over time as population changes.

    This also strongly suggests that the idea of using centres with populations averaging 147,000 as “rural” for baseline purposes is itself alone a good cause for dismissing the studies on the Chinese data.

  13. Paul Linsay
    Posted Nov 3, 2010 at 8:08 PM | Permalink

    City people have been spending the summers in rural areas for a long time. My father once told me about being a little boy, about the time of WW I, when the whole household would pack up each year and stay in a summer house for the season to escape the heat. His father would commute from the city on weekends.

  14. Steve McIntyre
    Posted Nov 3, 2010 at 9:24 PM | Permalink

    Folks, can we please NOT discuss general points about UHI.

    What we’re discussing here is the phenomenon of Jones et al 1990 and why its “proof” that urbanization contribution was so small. I realize that people have their own opinions, but as always the focus of this site is understanding/auditing the arguments which led Jones to believe that the urbanization contribution was so small and why this was such a consensus.

    This can’t be done by restating evidence of the existence of a UHI.

    • Dave Dardinger
      Posted Nov 3, 2010 at 10:48 PM | Permalink

      Re: Steve McIntyre (Nov 3 21:24),

      Well, for Pete’s sake, just how CAN we understand how these people were able to ignore common sense? I’m not saying that they didn’t present reasons, it’s just that the reasons given don’t pass the smell test. Personally I’m convinced it’s a psycho-political syndrome which prevents people from comparing known facts with results necessary to maintain a philosophical position. I.e. if UHI isn’t something really low like .05 deg/century then the degree of Anthropic warming will be too low to push for the political changes necessary to combat that warming. So the results which give the desired figure are accepted without detailed examination.

      Now this early study relying on Chinese data works if you don’t audit the actual data, and I suppose it’s often necessary to assume supplied data is correctly described, but if Jones et. al. had looked at the physical deductions of the results, they should have realized they were doubtful and gone looking for proof before they published. That they didn’t can be labeled as you wish, but nobody here is going to let them off the hook for not having done due diligence.

    • Hank Henry
      Posted Nov 4, 2010 at 8:55 AM | Permalink

      A general question: I thought I’d try to slip it in here. Are the mechanics of a UHI well understood? Are there papers published on that topic?

      Steve – yes, there are interesting specialist articles on the topic and occasional posts on the topic at CA if you at the “Categories”.

  15. Gerald Machnee
    Posted Nov 3, 2010 at 9:54 PM | Permalink

    This has been a long time coming. Does the brightness come into play anywhere here? Great work Steve.

  16. Bernie
    Posted Nov 3, 2010 at 10:49 PM | Permalink

    I am looking forward to your forensic analysis of this piece of Jones’ and Karl’s legerdemain.

    42 matched pairs of urban and rural stations compared over a 30 year period (that includes Mao’s great leap backwards) clearly needs some pretty robust station histories. Without those histories IMHO the analysis is essentially useless. Moreover, if UHI is a log function of population then you actually need to compare non or really slow growth station locations with fast growth station locations – assuming many other micro-climate factors remain more or less constant. The rural-urban split may be extremely misleading in assessing the UHI effect. Even with excellent station histories, this would still be a pretty challenging piece of analysis given the number of potential variables that need to be modelled.

  17. Dave L.
    Posted Nov 3, 2010 at 11:14 PM | Permalink

    Regarding the missing station histories — I gather that a major issue is whether or not the missing histories could have been fabricated (or just disregarded). Yes?

    Conversely, cannot one “eyeball” a station data graph and detect obvious station moves or instrumentation changes? And then make adjustments?

    Even if one has a detailed history indicating station moves, but on “eyeballing” the data graph there is no obvious offset effects correlating to the moves, does that mean no adjustments are to be made?

    What I am getting around to is: If you “eyeball” a station data graph and see no obvious offset patterns, would it make any difference whether or not a station history existed?

    Steve: no one has suggested that the station histories were “fabricated”; the question was whether they existed .

    • TerryS
      Posted Nov 4, 2010 at 3:54 AM | Permalink

      Eyeballing a data graph would not tell you the cause of a step change. It is possible for it to be a natural phenomena.
      Moving a station might not result in a step change that can be reliably detected by an eyeball.
      Jones claim is that:

      we chose those with few, if any, changes in instrumentation, location or observation times.

      Without the histories his selection criteria is useless.

    • PhilH
      Posted Nov 4, 2010 at 2:12 PM | Permalink

      “Steve: no one has suggested that the station histories were “fabricated”; the question was whether they existed”

      Well, if they didn”t exist, and they are included in the paper/data, they would have to have been fabricated; wouldn”t they?

      Steve: “station history” in this context is the meta-data of moves, not the monthly temperatures. I’ll clarify this for people unfamiliar with the jargon.

  18. theduke
    Posted Nov 3, 2010 at 11:45 PM | Permalink

    It amazes me that Jones et al could have published such a flawed study in 1990 and that it has not been resoundingly (and repeatedly) refuted by other so-called “climate scientists” in the ensuing 20 years.

    Why is that?

    Confirmation bias?

  19. Geoff Sherrington
    Posted Nov 4, 2010 at 12:08 AM | Permalink

    While this is about China, Australia was in the trio and it should have alerted Jones to problems there. In 1992 the Melbourne “Age” newspaper published the following, which was later in a BOM report. It shows a one night traverse of about 40 km, with a temperature difference of 7 degrees C from city fringe to city centre. One would expect such information to cause Jones to re-examine his 1990 inferences.

    Please keep in mind that papers about proxy studies that use invalid temperature calibration are wrong and require correction or withdrawal. Have you seen many corrections or withdrawals lately?

    In the early 1990s I visited some of the Chinese places mapped above (so far as I can plausibly place them). I have an impression that such metadata sheets as exist would need very close examination. Some of the sites exist because of heavy industry. Chinese industrial cities would in general have had a higher population per unit area than western cities and this could lead to UHI amplification.

    • Posted Nov 4, 2010 at 8:52 PM | Permalink

      The problem with such a traverse is that you could get such temp differences in less distance without cities being involved.

  20. Duke C.
    Posted Nov 4, 2010 at 12:11 AM | Permalink



  21. John Meech
    Posted Nov 4, 2010 at 2:04 AM | Permalink

    While I don’t wish to come to the defence of Jones and his cronies, please keep in mind that his statement that the UHI effect is only 0.05 °C is with respect to the temperature anomaly at any specific site and not on the specific temperature difference measured at an urban site vs a rural site. There is a significant difference in these two cause and effect measurements. I look forward to reading the remainder of Steve McIntyre’s analysis and expect that he will ensure that we are talking about the same output – site temperature anomaly, not difference between rural and urban sites.

    Steve: I am fully aware of the distinction that you have in mind and use the term “urbanization contribution” in referring to the contribution of increases in UHI to temperature trend (as distinct from “UHI” to refer to the effect at a point in time.)

    • bobdenton
      Posted Nov 4, 2010 at 4:25 AM | Permalink

      — or the difference in the anomaly between “rural” and urban sites

    • Cold Lynx
      Posted Nov 4, 2010 at 6:50 AM | Permalink

      You can not have a temperature difference between rural and urban sites out of the blue.
      Is there a temperature difference, as it is well known to be, must that temperature difference have a cause. That cause must be a function of something. Probably not binary by put the label rural of urban site.
      That trend is by Jones et al said to be close to zero. The implication by that statement is that some rural sites must been warmer from the beginning of the world. And by a lucky coincident chosen to be populated by humans.
      Unless there is some function of size, population, energy use, ground material or any combination of different reasons caused by humans that change the temperature in urban locations. That are probably also why no one cared about the “result” then. It was such a poor paper so no one bother to argue, or spend any time on that basic misunderstanding.

    • John Meech
      Posted Nov 4, 2010 at 10:54 AM | Permalink

      Steve, I understand that you are looking at the same output as Jones and that you understand the distinction between temperature and temperature anomaly. But when you call it a temperature trend I think that can lead to a misunderstanding on the part of others. I think it would be helpful if you make it clear that you are referring to the trend in “temperature anomaly” at a site, not temperature trend at a site.

      We could, of course, have an entirely different debate about the credibility or lack thereof of what an anomaly really is, how it is properly analysed, and how it changes for different reference temperature or time points, but in my opinion this is an entirely different subject.

      Steve: the subtraction of a reference temperature isn’t going to affect the trend: the temperature trend and the temperature anomaly trend are going to be the same. I don’t understand your issue here.

      • John Meech
        Posted Nov 4, 2010 at 12:22 PM | Permalink

        Sorry to harp on this matter but I believe it is important to avoid any misunderstandings about what is being compared.

        I take your point about the subtraction of a constant reference temperature not affecting the trend in temperature change over time at any one point on the surface of the earth.

        But when you say “trend in temperature” I think some readers are interpreting this as a direct comparison of urban and rural temperatures at any point in time.

        By using the term “temperature anomaly”, I think this is more clear and in accord with what Jones examined.

        If Jones is correct, then you should see the same temperature trend for urban and rural sites that have been matched with respect to other variables (elevation, topography, latitude, etc.). If Jones is incorrect in his analysis then the temperature trends at each matched pair should show a bias towards urban sites (i.e., a higher trend as the population grew.). This difference should demonstrate a measure of the UHI that is over and above the specific effect on temperature. One of many difficulties is that the UHI effect likely eventually levels out and the trend will become independent of population increase at some point in time. If that data represents the majority of the time series then a false conclusion will result as reported by Jones.

        Steve: if the rural sites are also urbanizing, the interpretation of a comparison is not simple.

  22. Posted Nov 4, 2010 at 2:05 AM | Permalink

    Places change. Urbanization is real. This might effect surface temp measurements. A lot.

    I am looking forward to Steve’s coming episodes.

    Reality has a nasty habit of biting back.

    • John Meech
      Posted Nov 4, 2010 at 3:04 AM | Permalink

      I quite agree – Urbanization is real and the surface temperatures will be higher than at rural sites. There is no dispute about that fact as any school child will attest.

      But that difference is not what Jones et al were referring to. They claim that the site temperature anomaly for pairs of rural sites and urban sites is only different by about 0.05. Anomaly refers to the difference between the temperature at a site and the average temperature at that site over the period of measurement or at some particular reference point in time. The selection of that reference temperature must be chosen in the same way for both the urban and rural sites.

      • Phil
        Posted Nov 4, 2010 at 4:21 AM | Permalink

        Re: John Meech (Nov 4 03:04),

        Jones, et. al. are looking at trends over about a 30 year period and saying that this period is representative of changes occurring over a 100 year period. Additionally, they may also be disregarding saturation effects such as population density and/or energy use per capita. If there was no significant population density change over the about 30 year period of their study and/or energy use per capita, they might not have been able to detect any UHI trend. However, it is almost certain that there were strong changes in population density and energy use per capita over the last century or so.

      • Dave Dardinger
        Posted Nov 4, 2010 at 9:13 AM | Permalink

        Re: John Meech (Nov 4 03:04),

        They claim that the site temperature anomaly for pairs of rural sites and urban sites is only different by about 0.05.

        Could I have an actual quote on that? I don’t recall that being what they said. What they said is that the global trend was only affected by about .05 deg C over the past century. Since humans don’t live everywhere (far from it)there is a major factor between urban-rural differences and global trend differences. But there are two other factors to be considered. One is what Steve is discussing here, to what extend is the result correct and two to what extent does the incorrect urban-rural calculations result in incorrect determination of temperature trends in land surfaces?

        • John Meec h
          Posted Nov 4, 2010 at 2:23 PM | Permalink

          The issue is not the effect of UHI on global temperatures (which is probably small).

          The issue is the influence of UHI on our ability to accurately measure temperature changes over time. If the UHI affects our measurements, then with increasing urbanization, clearly we will see the temperature measurements rise, but that set of measurements is meaningless in terms of global mean temperature changes.

        • Dave Dardinger
          Posted Nov 4, 2010 at 5:01 PM | Permalink

          Re: John Meec h (Nov 4 14:23),

          First I need to correct myself in light of having reread the head post. the .05 deg per century was for land surface, not the whole globe, which makes it even less plausable.

          Your point is correct that because most all stations, including those nominally considered “rural”, are actually prone to urbanization, meaning there’s a difficulty determining how much of a measured temperature increase is actually AGW and how much UHI (not to mention how much is natural variation). But that’s not what this post is about. It’s about where the problems are in Jones, et. al. 1990.

        • hr
          Posted Nov 8, 2010 at 4:26 AM | Permalink

          I think the relevant passage in the main text of Jones et al (1990) is: “It is unlikely that the remaining unsampled areas of the developing countries in tropical climates, or other highly populated parts of Europe, could significantly increase the overall urban bias above 0.05C during the twentieth century.” (p.172, penultimate paragraph). I have found no other mention of the 0.05C figure in the paper, except where it is implied in the final sentence of the abstract on p 169 (see below).

          The above passage seems to be combining (a) the authors’ conclusions from all 3 regions included in the 1990 study (eastern China, eastern Australia and European parts of Soviet Union) with (b) results from earlier studies of the contiguous USA and (c) data from other yet to be sampled land areas. The 0.05C seems to refer to this combination of (a), (b) and (c). But maybe I have misunderstood it. Anybody else like to venture an opinion?

          Another point which is worth bearing in mind is that although the data on eastern China came from 42 pairs of geographically associated ‘rural'(in fact small town) and ‘urban’ (big city)sites, it seems that Jones et al (1990) did not make comparisons between the two individual members of each pair. Instead “From the 42-station rural network, we formed an average (RCHI, Fig. 2c) for eastern China using the inverse-weighting gridding scheme. The 42 station urban network (UCHI) was averaged in the same way.” (p 171)
          (Can anyone tell me what ‘inverse-weighting gridding scheme’ means?)

          Later on in the paper (top of p 172) is the following passage: “The warming in UCHI is 0.39C, considerably higher than that in RCHI. For this region, UCHI is the only series for which warming is statistically significant.” It should be noted that the 0.39C warming referred to here was over a period of 3 decades (1954-1983). Warming of 0.23C was found in the corresponding ‘rural’ set over the same 30 year period, but not considered to be statistically significant.

          This interesting result is however apparently disregarded in the conclusion (penultimate para of p 172, see above) and in the summary (p 169) which reads “The results show that the urbanization influence in two of the most widely used hemispheric data sets (refs to 3 earlier papers) is, at most, an order of magnitude less than the warming seen on a century timescale”.

          The later paper by Wang et al (1990) does however treat the same 42 station pairs as individual pairs and comes up with different conclusions as to the magnitude of the urban effect on warming trends in eastern China. I find it interesting that Wang and Karl, who had both been co-authors of Jones et al (1990), found it necessary to publicly contradict in Wang et al (1990) conclusions which they themselves had signed up to less than 3 months previously.

          Chronology of the two papers:
          Jones et al: published 13 September 1990, Nature.
          Wang et al: received 24 August, revised 12 October, accepted 15 October, published December 1990, GRL.

  23. mondo
    Posted Nov 4, 2010 at 3:45 AM | Permalink

    At the risk of being pedantic, can I urge that we recognise the difference between UHI effects, and Delta UHI over time. The reason for stating this is that anybody can observe the UHI effect in a town or city simply by observing the temperature record in his car as he drives across the town or city.

    However, what is really important is the change (thus Delta) in UHI over time, since that is what is affecting the temperature records. Not the observable UHI effect today.

    To state the obvious, some temperature records began when the observing location was truly rural (ie no observable UHI effect) and then over time, the population grew so that the observing location is now in the middle of a city of, say, 500,000 people. It is the change over time that is adding the artefact to the temperature record, showing ‘warming’ that is due to the city effects, not AGW.

    • Posted Nov 4, 2010 at 4:49 AM | Permalink


      You might consider it pedantic and obvious, I prefer “useful”. Thanks.

      • JohnH
        Posted Nov 4, 2010 at 5:01 AM | Permalink

        The UK was the first country to have an industrial revolution, so for the 20th Century the UHI effect you would expect to be close to nil as all the Urbanisation had already taken place, UHI is present but is not increasing. China is in the full throes of its industial revolution so the increase of the UHI affect as populations move from rural to urban areas should show an increase in UHI effect, which is why the 1990 study is so important.

        • curious
          Posted Nov 4, 2010 at 5:39 AM | Permalink

          JohnH – I’m not sure that your point re: the UK having a stable C20 UHI “profile” will be correct. There have been significant changes in our cities due to road transport and there are definite street canyon effects due to localised intense traffic. I think that other factors such as land use change and intensification will also play a part. My expectation is that one will need to look in detail at the station locations and associated metadata to analyse a UK UHI profile before one could draw conclusions. Perhaps this work has been done already?

        • johnh
          Posted Nov 4, 2010 at 6:31 AM | Permalink

          Curious, you are right but it should still be a lot less than the first effect of moving from Rural to Urban on industrialisation.

          I was trying to point out that what the study was supposed to be looking at was the change in UHI over several years not the effect of UHI in the center of a city compared to the outskirts at a piont in time.

        • Stan Palmer
          Posted Nov 4, 2010 at 7:37 AM | Permalink

          As has been pointed out by many in the sustainability movement, the use of energy within households and offices rose dramatically in the latter part of the 20th century in Europe and North America. People stocked their hosues with power consuming electronics, air conditioners, refrigerators etc. Look at movies from teh 1930s, 40s or 50s. Houses had very little in the way of appliances or entertainment systems. Look at movies from the 1980s or 90s, there were no computers in houses. Now the multi-television, multi-computer house is the standard. Teh kids have their computers in their own rooms as well their own televisions, X-box … In movies from the 30s, children were sleeping in the same room with multiple kids per bed. Hot water was a luxury in the 30s.

          Energy use per capita must have risen dramatically and the urban population and that energy must be going somewhere. The UHI delta over this period is something that must be confirmed. It is not obviously negligible

        • Nusquam Nihil
          Posted Nov 4, 2010 at 4:17 PM | Permalink

          David S,

        • lapogus
          Posted Nov 5, 2010 at 5:14 AM | Permalink

          @ Stan –

          Yes, but remember that this increased energy use is only part of the UHI effect. Land use changes (more ashphalt concrete etc.) are also significant, expecially in summer. However, the former, which I label AHE (Anthropogenic Heating Effect but there’s probably a more scientific term) is probably more interesting. Globally the extra heat generated by AHE is neglible compared with the output from the Sun, and it’s a even a small fraction of the alleged extra forcing from our increased CO2 emissions. But locally AHE can (especially on windless days/periods) be very significant, especially in winter – Russian/Siberian station data confirms this. I did some rough calculations for London and concluded that in the right atmospheric conditions (i.e. a stable area of high pressure, lasting for a few days), AHE could have a regional rather than just ‘local’ effect.

    • Mark Cooper
      Posted Nov 4, 2010 at 8:47 AM | Permalink

      I hope Steve can forgive me for continuing the general discussion on UHI here in this thread.

      I feel I should point out that the UHI effect in China may be considerably different from UHI effects we are familiar with in Europe/USA.

      There are clearly problems with a lot of weather stations placed in car parks etc, and clearly increased building density in formerly agricultural areas/wilderness increases UHI.

      However, in Desert/tundra areas, UHI is much less pronounced, and as ‘Kenskingdom’ demonstrates on his excellent blog, he has identified several “Urban Cooling Islands” where urbanisation has created a negative Delta temp in Australia.

      • tty
        Posted Nov 4, 2010 at 12:44 PM | Permalink

        That UHI is slight in desert environments seems plausible. However studies in Point Barrow and Longyearbyen both show very pronounced UHI even in these quite small towns in the tundra zone. Not that there is any large cities there.

    • TerryMN
      Posted Nov 4, 2010 at 5:11 PM | Permalink


      I would heartily agree with the UHI delta argument if I believed that metropolitan areas, in general, had maintained a static population and level of development over the past several decades (or centuries, or whatever – pick your timeframe). As it turns out, the vast majority have grown – more (and higher) buildings which draw more commuters, in addition to more city dwellers, more transportation, more power demand and use, etc. etc.

  24. Patagon
    Posted Nov 4, 2010 at 4:21 AM | Permalink

    There is an interesting point here that illustrate the confusion between correlation and causation.

    Bohm has shown that urban heating is not proportional to population but to energy consumption. This makes sense, energy dissipates as heat and it is far larger than human body heat generation. Urban landscape change, such as area of parks etc, also has an impact (Climatic Change Volume 38, Number 1, 113-128 )

    If we clear urban stations as unbiased for the global temperature record, what we are doing is actually using that temperature record as an indication of global energy consumption. As energy consumption is directly proportional to CO2 production, it is easy to establish a link between CO2 and temperature trends. See for example the pattern of China’s energy use: , which adds support to the use of data prior to 1990.

    Of course nature loves cycles and sometimes the clear trends are spoiled.

  25. Varco
    Posted Nov 4, 2010 at 8:26 AM | Permalink

    Your excellent work prompted me to want to read the Jones et al 1990 paper. I found a copy on-line at Apologies in advance as I am sure this is ‘old news’ to yourself.

    Table 1 in Jones et al 1990 highlights a large discrepancy between the Rural (‘RCHI’) and Urban (‘UCHI’) temperature trends for China:

    Linear trend (deg C over period 1954 – 1983)
    RCHI (Rural) = 0.23 (inverse-weighted gridded scheme of 42 station rural data from Ref 1)
    JCHI = 0.19 (regional time series based on data from Ref 1)
    VCHI = 0.13 (Average series developed from data in Ref 4)
    UCHI (Urban) = 0.39 ((inverse-weighted gridded scheme of 42 station urban data from Ref 1)

    The UCHI 0.39 result was stated to be a ‘significant trend at the 5% level’.

    The text goes on to say “The warming in UCHI is 0.39 deg C, considerably higher than that in RCHI. For this region, UCHI is the only series for which warming is statistically significant. The Chinese results may, at first glance, seem somewhat surprising, as 24 of the stations used in ref. 1 are among the 42 urban sites.”

    OK, so far…but!

    I am struggling with the logic leap to the statement in the next paragraph, “In none of the three regions studied here is there any indication of significant urban influence in either if the two gridded series relative to the rural series.”

    Am I missing something obvious regarding how the ‘statistically significant’ China UCHI result became the conclusion “Thus there seems to be little urbanization influence in three regions of the world that, when taken together, are twice the size of the contiguous United States.”?

    Steve: I don’t blame you for being puzzled. I checked against Jones’ own data and there was a “significant” difference in trend between Chinese urban and Chinese “rural”, despite the statements in Jones et al 1990. As I said, it seems like a Coen Brothers movie.

    • Posted Nov 4, 2010 at 11:35 AM | Permalink

      Re: Varco (Nov 4 08:26),
      I think the excuse would be in the S.D which is 0.3. Therefore the urban warming of 0.39 counts as significant. But the ‘urban influence’ is the difference between urban and rural, 0.39 – 0.23 = 0.16 which is less than 0.3 and therefore ‘not significant’.

      I’m not trying to defend the paper at all – it is junk science.
      The figure of 0.05 degrees per century that appears towards the end has just been plucked out of thin air. It seems that this number was invented by Jones in 1990 and used again by him in IPCC AR4 with no justification.

      Steve: please be precise: Jones et al 1990 purports to justify 0.05; their argument may be flawed, but that’s a different point.

      • Posted Nov 5, 2010 at 4:25 AM | Permalink

        Re: PaulM (Nov 4 11:35), Steve, do they? I have just read it again and I cannot see any justification for the figure of 0.05 for the century. It is just stated in the penultimate paragraph.

        • Varco
          Posted Nov 5, 2010 at 7:44 AM | Permalink

          PaulM, I agree. I could not see any justification. It was as if a paragraph/page was missing.

          Thanks for the S.D. observation.

  26. Dick Atkinson
    Posted Nov 4, 2010 at 9:57 AM | Permalink

    I don’t understand the purpose of the Jones et al 1990 research. If sites can be identified as urban and rural, then a temperature trend for all the rural sites can be determined, and likewise a trend for all the urban sites. If there is a significant difference, it should be apparent right there. The matching of the 42 pairs for the study seems to discard a lot of data (hundreds of sets?), and also to raise a further question about the matching itself – how can a pair of sites be matched in order to investigate an effect whose details may invalidate the matching? Still, 42 is the answer to Life, the Universe and Everything.

    • Bernie
      Posted Nov 4, 2010 at 10:30 AM | Permalink

      The urban and rural distinction is highly ambiguous. Presumably the authors wanted to compare station sets with a priori low and high UHI effects. But as others have said above, the issue is the UHI effect as a trend over time. It is quite possible, indeed likely, that a town that grows from 20,000 to 100,000 will have a bigger UHI effect than one that grows from 500,000 to 580,000. The population and other station history data are so important. The Jones et al (1990) Nature paper strikes me as being very weak methodologically. The use of the 1983 census data to designate rural (low UHI) and urban (high UHI) is simply egregiously flawed logic.

  27. Stacey
    Posted Nov 4, 2010 at 10:05 AM | Permalink

    “The concept was entered into academic literature at least as early as Oke (1976…”

    Steve, Professor Manley was discussing this effect in 1953 and in his later paper circa 1973 omitted a station close to Oxford due this effect.

    Click to access QJ53manley.pdf

    Click to access qj74manley.pdf

    I hope this is not off topic but the graphs he prepared from the temperature data do not look like Hockey Sticks also there is some statistics used in dealing with urbanisation/adjustment of the temperatures but but I am not competent in this field.

    If OT please delets.

  28. Stacey
    Posted Nov 4, 2010 at 10:07 AM | Permalink


    I don’t seem to be able to post?

  29. Fred
    Posted Nov 4, 2010 at 10:36 AM | Permalink

    ““Why should I make my data available to you when your only objective is to find something wrong with it?” ”

    Good description of the modern version, especially the Climate Science version, of the old fashioned Scientific Method.

    Wonder what could go wrong with such a method?

  30. GolfCharley
    Posted Nov 4, 2010 at 11:16 AM | Permalink


    Steve, is this the direction you wanted this thread to go in? Please delete if not

    not yet. I’m going to bring this topic to the present.

  31. jgc
    Posted Nov 4, 2010 at 12:18 PM | Permalink

    My coment is awaiting moderation since 4:21AM,
    Is my IP filtered?
    Your comment is awaiting moderation.

    There is an interesting point here that illustrate the confusion between correlation and causation.

    Bohm has shown that urban heating is not proportional to population but to energy consumption. This makes sense, energy dissipates as heat and it is far larger than human body heat generation. Urban landscape change, such as area of parks etc, also has an impact (Climatic Change Volume 38, Number 1, 113-128 )

    If we clear urban stations as unbiased for the global temperature record, what we are doing is actually using that temperature record as an indication of global energy consumption. As energy consumption is directly proportional to CO2 production, it is easy to establish a link between CO2 and temperature trends. See for example the pattern of China’s energy use: , which adds support to the use of data prior to 1990.

    Of course nature loves cycles and sometimes the trends get spoiled

  32. Ron Cram
    Posted Nov 4, 2010 at 12:38 PM | Permalink

    Steve, I am not sure how one would calculate the effect of UHI on global temperature trend. Let’s take the US for example. What percentage of US land area is rural? What percentage of land area is urban? My guess is the urban area is insignificant compared to the rural area. There are lots of mountains, deserts and lakes where no one lives for miles around. But that really isn’t the main issue, is it?

    The real question: Is our temperature measuring network established in rural or urban areas? Are those stations good quality stations? This is the work is doing. Without that level of analysis, Jones et al 1990 is completely worthless.

    Steve: I urge readers to read the articles in addition to criticizing them on other grounds.

    • Ron Cram
      Posted Nov 4, 2010 at 1:29 PM | Permalink

      Steve, I look forward to your future posts. I hope you address the issue of false precision.

  33. andy
    Posted Nov 4, 2010 at 12:48 PM | Permalink

    Let me guess, the ‘rural’ stations are not rural and so comparing ‘urban’ with ‘urban’ leads to no influence on temps from the UHI effect.
    Or the stats is all bunk!

    I cannot wait for the next installment!

  34. PhilH
    Posted Nov 4, 2010 at 3:11 PM | Permalink

    Okay, John Meech, Steve, I’m just a lawyer and I need some help here. I am confused by the apparent difference between what Anthony Watts and Phil Jones are saying about UHI.

    Let’s make up an example: Bozeman, Montana (pop. 30,000, alt. 5,000) where the average temperature, pick a figure, is 60 F. Nye, Montana, where I lived for a while (the population there on a big Saturday night averages about nine folks and the altitude is also 5,000 ft)and where the average temperature is 55 F. I understand Anthony is saying, because the thermometer is located in the center of Bozeman, the temperature is, say, up to 5 degrees hotter there than Nye, or something close to that, and therefore the overall temperature of Montana is skewed significantly higher by UHI.

    Phil Jones, I understand, measuring only change, is saying, and assuming for the moment that his calculations and data are right, that Bozeman is only 0.05 C. warmer now than it was fifty years ago when, presumably it had way fewer people, roads, etc. Nye is just where it always has been. Therefore the figures, with slight adjustment, are overall just as correct now as they have ever been for Montana.

    But how can that be? It seems to me that Anthony and Jones cannot both be right, regardless of the differences in what they are measuring and/or presuming.

    • John Meechjamee
      Posted Nov 4, 2010 at 4:02 PM | Permalink

      They are both measuring the same thing – temperature at both sites and over time. It is the method of analysis that is different. To try to understand the warming trend and to define it with more rigor, Jones et al are looking at the amount of change in temperature at each site over time (the temperature anomaly trend) – this is determined by subtracting from each temperature reading the average temperature of the time series or a specific temperature measurement at some specific point in time. They then compare this “anomaly” at different sites. Now what is further done to massage this data is to adjust for different latitudes, different elevations, and sometimes different weather parameters before calculating the anomaly.

      What Steve is looking at is the comparison of the temperature trend over time of an urban site with a rural site. While the relative position of these graphs will definitely be biased towards the urban setting, the question is whether there is a difference in the slope of these two measurement trends – that slope is equivalent to the anomaly used by climate scientists.

      It is accepted by all that there is a UHI effect on the temperature measured in an urban setting over a rural one and that this difference is a function of population (it is suggested that the effect is logarithmic) and eventually levels off at some population point. What is in dispute is whether the UHI affects the anomaly or slope in the temperature-time graph.

      • Steve E
        Posted Nov 4, 2010 at 6:06 PM | Permalink

        Thank you!

        That is the best description I’ve seen anywhere about what some perceive to be apples and oranges.

      • Posted Nov 5, 2010 at 12:22 AM | Permalink

        What Anthony was/is doing is more like showing how encroachment on the actual monitoring stations can cause a systematic bias over time. If, say, 100 years ago a specific monitoring station was in a green pasture, then 20 years later some houses were built within 100 feet of the station. Then over the next 20 years roads were slowly added. Then over the next 20 years shopping centers were added, blacktop, etc, very close to the station. Or maybe the station, at this point, was moved to a roof because there was no more room on the ground. Such a station would show a continuous rise in temperature over the last 100 years. The “anomaly” would deviate from the baseline in a steady manner. You get enough of these kinds of scenarios and the whole of the collection of records for multiple sites can become grossly biased. Station histories won’t necessarily show all these potential encroachments and heat sources within the microsite of the thermometer.

  35. TGSG
    Posted Nov 4, 2010 at 3:21 PM | Permalink

    heh, this will certainly be interesting. The first segment has been.

  36. Max Beran
    Posted Nov 4, 2010 at 3:46 PM | Permalink

    I realise that this is largely about China but even so many of the comments that point out that UHI is old news miss an important point. The relevance of UHI in the context of global warming studies lies not in whether UHI exists but in whether it affects the estimates of trend. And I emphasise “estimates” of trend rather than the “true” trend. Globally the dominance of oceans and long-standing urbanisation in some parts would suggest UHI is not a big deal for the “true” trend. But estimated trend is biassed by the fast depleting network with survivors tending to be near urban centres and their “contamination” of remote areas through the spatial extrapolation procedure extending perhaps hundreds or even thousands of km into their hinterland and well offshore.

  37. bill
    Posted Nov 4, 2010 at 4:10 PM | Permalink

    Jones purports to be analysing 30 years worth of Chinese weather records. Why should their records be considered in any way credible? Particularly 1967-70, plus the time it took China to recover from that upheaval.
    But, were climate scienttists to acknowledge the possibility that ‘records’ are made up/missing/meaningless, much of their position would crumble. They are obliged to ‘believe’. Thus post 1960s Africa evidently has a perfect climate record, a useful component in helping us compute the global temperature picture.

  38. Steve E
    Posted Nov 4, 2010 at 5:25 PM | Permalink

    Luke Howard, an English meteorologist, is usually credited with being the first to describe the UHI, based on his temperature studies in London and the surrounding countryside in the early 1800s. He didn’t coin the term but he clearly pointed out in his published studies that the urban area was consistently warmer than the surrounding rural areas. This is commonly taught in introductory physical geography (and presumably other) classes.

  39. Frank
    Posted Nov 5, 2010 at 2:10 PM | Permalink

    Steve: Thanks to Varco’s link, I read the Jones 1990 Nature paper and found it totally absurd. Jones analyzes SMALL paired sets of urban and rural stations for three regions. If I am reading Table I correctly, these data sets are so small and/or cover such a short period of time that NO STATISTICALLY SIGNIFICANT warming can be found in one region (USSR), while warming reaches statistical significance in urban, but not rural, China and both areas of Australia. Then, with data sets so small that warmings of 0.23 degC in 30 years (China) and 0.38 degC in 86 years (USSR) are not statistically significant, he concludes that UHI has to be less than 0.05 degC for the whole explicative-deleted century! The error in the difference of two means (urban vs rural) must be greater than error in the means themselves. (ca 1.4X greater). The only changes that reach statistical significance are ca 0.50 degC over 58 years and 0.39 degC over 30 years, about 0.1 degC/decade for data sets and 0.15 degC/decade for the difference between data sets, which is 1.5 degC for the century.

    (I presume you and others must have noted these problems sometime in the past, but you haven’t mentioned them yet in this series of posts.)

  40. Chris BC
    Posted Nov 8, 2010 at 2:21 AM | Permalink

    The usual fine work and extensive research here in installment 1, along with an unfortunate reminder of what is perhaps Steve’s worst flaw.

    When you consider everything that is blatantly obvious about UHI over time, including the growth of air conditioning and other energy use, as well as pavement and asphalt (as pointed out above by others), the veracity of Jones 1990 is not really in question. It is very quickly obvious that you are faced with two options, either they are extremely ignorant or they are lying. Given their educations and positions the former is extremely unlikely, and that leaves us with Keenan’s position. And that’s really the best way to put it.

    Onward to part 2.

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