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New Study Shows NOAA Overestimate US Warming By 50%

December 17, 2015

By Paul Homewood 





A paper has been published submitted, showing that bad siting of temperature stations has resulted in NOAA overestimating US warming trends by about 50% since 1979.

The study by Anthony Watts, Evan Jones, John Nielson-Gammon and John Christy has carefully identified a subset of 410 USHCN stations, that have not been moved, had equipment changes, or changes in time of observations, and thus require no “adjustments” to their temperature record to account for these problems. From within this subset, the trend for high quality sites has been compared with the rest.


The Press Release gives the details:   




SAN FRANCISCO, CA – A new study about the surface temperature record presented at the 2015 Fall Meeting of the American Geophysical Union suggests that the 30-year trend of temperatures for the Continental United States (CONUS) since 1979 are about two thirds as strong as officially NOAA temperature trends.

Using NOAA’s U.S. Historical Climatology Network, which comprises 1218 weather stations in the CONUS, the researchers were able to identify a 410 station subset of “unperturbed” stations that have not been moved, had equipment changes, or changes in time of observations, and thus require no “adjustments” to their temperature record to account for these problems. The study focuses on finding trend differences between well sited and poorly sited weather stations, based on a WMO approved metric Leroy (2010)1 for classification and assessment of the quality of the measurements based on proximity to artificial heat sources and heat sinks which affect temperature measurement. An example is shown in Figure 2 below, showing the NOAA USHCN temperature sensor for Ardmore, OK.

Figure 2 – USHCN Temperature sensor located on street corner in Ardmore, OK in full viewshed of multiple heatsinks.

Following up on a paper published by the authors in 2010, Analysis of the impacts of station exposure on the U.S. Historical Climatology Network temperatures and temperature trends2 which concluded:

Temperature trend estimates vary according to site classification, with poor siting leading to an overestimate of minimum temperature trends and an underestimate of maximum temperature trends, resulting in particular in a substantial difference in estimates of the diurnal temperature range trends

…this new study is presented at AGU session A43G-0396 on Thursday Dec. 17th at 13:40PST and is titled Comparison of Temperature Trends Using an Unperturbed Subset of The U.S. Historical Climatology Network


A 410-station subset of U.S. Historical Climatology Network (version 2.5) stations is identified that experienced no changes in time of observation or station moves during the 1979-2008 period. These stations are classified based on proximity to artificial surfaces, buildings, and other such objects with unnatural thermal mass using guidelines established by Leroy (2010)(1) . The United States temperature trends estimated from the relatively few stations in the classes with minimal artificial impact are found to be collectively about 2/3 as large as US trends estimated in the classes with greater expected artificial impact. The trend differences are largest for minimum temperatures and are statistically significant even at the regional scale and across different types of instrumentation and degrees of urbanization. The homogeneity adjustments applied by the National Centers for Environmental Information (formerly the National Climatic Data Center) greatly reduce those differences but produce trends that are more consistent with the stations with greater expected artificial impact. Trend differences are not found during the 1999- 2008 sub-period of relatively stable temperatures, suggesting that the observed differences are caused by a physical mechanism that is directly or indirectly caused by changing temperatures.

Key findings:

1. Comprehensive and detailed evaluation of station metadata, on-site station photography, satellite and aerial imaging, street level Google Earth imagery, and curator interviews have yielded a well-distributed 410 station subset of the 1218 station USHCN network that is unperturbed by Time of Observation changes, station moves, or rating changes, and a complete or mostly complete 30-year dataset. It must be emphasized that the perturbed stations dropped from the USHCN set show significantly lower trends than those retained in the sample, both for well and poorly sited station sets.


2. Bias at the microsite level (the immediate environment of the sensor) in the unperturbed subset of USHCN stations has a significant effect on the mean temperature (Tmean) trend. Well sited stations show significantly less warming from 1979 – 2008. These differences are significant in Tmean, and most pronounced in the minimum temperature data (Tmin). (Figure 3 and Table 1)


3. Equipment bias (CRS v. MMTS stations) in the unperturbed subset of USHCN stations has a significant effect on the mean temperature (Tmean) trend when CRS stations are compared with MMTS stations. MMTS stations show significantly less warming than CRS stations from 1979 – 2008. (Table 1) These differences are significant in Tmean (even after upward adjustment for MMTS conversion) and most pronounced in the maximum temperature data (Tmax).


4. The 30-year Tmean temperature trend of unperturbed, well sited stations is significantly lower than the Tmean temperature trend of NOAA/NCDC official adjusted homogenized surface temperature record for all 1218 USHCN stations.


5. We believe the NOAA/NCDC homogenization adjustment causes well sited stations to be adjusted upwards to match the trends of poorly sited stations.


6. The data suggests that the divergence between well and poorly sited stations is gradual, not a result of spurious step change due to poor metadata.

The study is authored by Anthony Watts and Evan Jones of , John Nielsen-Gammon of Texas A&M , John R. Christy of the University of Alabama, Huntsville and represents years of work in studying the quality of the temperature measurement system of the United States.
Lead author Anthony Watts said of the study: “The majority of weather stations used by NOAA to detect climate change temperature signal have been compromised by encroachment of artificial surfaces like concrete, asphalt, and heat sources like air conditioner exhausts. This study demonstrates conclusively that this issue affects temperature trend and that NOAA’s methods are not correcting for this problem, resulting in an inflated temperature trend. It suggests that the trend for U.S. temperature will need to be corrected.” He added: “We also see evidence of this same sort of siting problem around the world at many other official weather stations, suggesting that the same upward bias on trend also manifests itself in the global temperature record”.

The full AGU presentation can be downloaded here:



[1] Leroy, M. (2010): Siting Classification for Surface Observing Stations on Land, Climate, and Upper-air Observations JMA/WMO Workshop on Quality Management in Surface, Tokyo, Japan, 27-30 July 2010
[2] Fall et al. (2010) Analysis of the impacts of station exposure on the U.S. Historical Climatology Network temperatures and temperature trends




Congratulations to Anthony and Evan for putting so much effort into this important project. What is self evident is that the effect of bad siting and urbanisation will be much greater still if the analysis is extended back to the 1930’s.

Worse still, there are so many poorly sited stations that homogenisation is working to adjust the good ones to the bad, and not the other way round.

  1. Don B permalink
    December 18, 2015 2:17 am

    “5. We believe the NOAA/NCDC homogenization adjustment causes well sited stations to be adjusted upwards to match the trends of poorly sited stations.”

    Why isn’t this criminal?

    • December 18, 2015 8:58 am

      It is criminal. Telling a lie to make money is fraud.

      There was a similar situation in the UK. MPs decided amongst themselves that they were justified to have huge expense accounts because they all felt they deserved far more money and it was unfair they weren’t paid enough. So, a culture developed of wholesale fraud and corruption – which as the MPs policed themselves, none of them wanted to find anything wrong.

      Likewise, we are now seeing a culture of fraudulently corruption global data to get funding because they essentially police themselves and it is in none of their interests to sink the global warming gravy boat.

  2. December 18, 2015 3:47 am

    .324 / .204 = 1.5882, i.e. +58.82%
    So, to put it one way, NOAA exaggerated U.S. warming by about 59%.

    1 – (.204/.324) = 0.3704
    So, to put it another way, about 37% of NOAA’s reported U.S. warming is spurious.

    Also, note the starting date for this analysis: 1979. So the period analyzed includes the 1980s and 1990s warming period, but not the preceding cooling period.

    U.S. temperatures peaked in 1934, and then cooled for the next 45 years, until 1979. That long cooling period is not included in this analysis. Here’s a graph from a 1999 paper by James Hansen, et al (“figure 6”):

    • December 18, 2015 3:58 am

      BTW, that cold spike was 1979 in the USA:

      The late 1970s were pretty brutal in the USA.

    • December 18, 2015 3:59 am

      Oops, botched the link — sorry!

    • December 18, 2015 12:51 pm

      Between 1920 and 1935 the temperature rise rate was very high (about 1 deg K / decade), where was all the CO2 then???

      It must have suddenly dissolved in the oceans in 1940 to cool again.

      I wonder how the fantasy computer model of the world copes with these periods: or was that weather and not climate?

      • A C Osborn permalink
        December 18, 2015 3:08 pm

        NOAA have been busily writing out those temperature variations.

  3. John permalink
    December 18, 2015 4:38 am

    A poster presentation at the AGU meeting is not a “published paper.” Virtually every single abstract submitted to the conference which is not selected for an oral presentation is accepted as a poster without any formal peer review or evaluation. Please let us know when Mr. Watts actually submits his paper for review – we’ve been waiting half a decade now!

    • AndyG55 permalink
      December 18, 2015 5:14 am

      The full paper is there for you… review it

      oh.. wait.. you wouldn’t have a clue.

    • AndyG55 permalink
      December 18, 2015 5:16 am

      I’m sure if you ask AW for the data and processes, they will be forthcoming ..

      Unlike a lot of climate science™ trash.

    • AndyG55 permalink
      December 18, 2015 5:23 am

      I know a couple of guys who have done some peer-review in climate science™ (and a few who do other subjects..)

      They read the paper.. correct any obvious spelling or grammar errors ….

      and that’s about all.

      They make no attempt to check any calculations, the data integrity, or to see if the data really indicates what the paper is saying.

      So long as it is “on message” that is all that matters.

      Journal peer-review is just a small step in making a paper public.

      It is NOT part of the scientific process.

      It puts the paper forward for discussion… that is all.

      Anything on the web, particularly on sites like here, WUWT, SG, JoNova, will get a far more thorough review than many journal articles ever get…. and will be viewed by far more people.

      That is why the data and methodology absolutely MUST be available from day one.. so that ANYONE that wants to check the paper, can do so.

      IT DOES NOT MATTER WHERE AN ARTICLE IS PUBLISHED, so long as it can be checked for validity by anyone that wants to do that checking.

      • John permalink
        December 18, 2015 12:11 pm

        So where’s your thorough review of this poster?? Oh wait – don’t tell me you’re one of those climate science peer reviewers who checks grammar and then rubber stamps it because you agree with the conclusion!

        “Publishing” means something in the scientific literature. This ain’t that.

      • December 18, 2015 12:15 pm

        A part of the “Climategate” from Univ. of East Anglia, was extensive emails plotting how to remove editors from journals who were allowing papers refuting THEIR views. They asked that fellow “scientists” be pressured to not to publish in recalcitrant journals in the hopes of destroying both the journals and their editors. AndyG55 is correct. He is citing the “scientific method.” I have never been such a fan of “peer reviewed.” I believe this is a doorway to the sort of mischief we are seeing. Only one side is being heard and the peer review from their like-minded pals is a joke.

      • John permalink
        December 18, 2015 8:28 pm

        @botanyjrg, that is absolutely, 100% false. Not only is the Climate-gate e-mail a throw-away, sarcastic comment from one person, there is zero evidence that the Team or anyone else is gate-keeping the scientific literature. If that’s the case, then how was Nic Lewis able to publish? Or Curry and Wyatt? Or McIntyre and McKitrick?

        If there really is a gatekeeper, then how come there isn’t a single documented case of a skeptic submitting a paper and it being rejected for bogus reasons?

    • December 18, 2015 8:48 am

      You clearly did not read the WUWT article, it had been submitted.

      • John permalink
        December 18, 2015 12:10 pm

        “Submitted” is not “published.”

        We’re so close to victory… why do we have to minimize it with hyperbole and BS? Watts presented a poster at the AGU, big freaking deal. The published paper will be a big deal, but we’re not there yet.

      • December 18, 2015 2:54 pm

        This is a hugely important study that people have a right to know about, just as those at the AGU Conference have.

        As Anthony Watts says:

        We are submitting this to publication in a well respected journal. No, I won’t say which one because we don’t need any attempts at journal gate-keeping like we saw in the Climategate emails. i.e “I can’t see either of these papers being in the next IPCC report. Kevin and I will keep them out somehow — even if we have to redefine what the peer-review literature is!” and “I will be emailing the journal to tell them I’m having nothing more to do with it until they rid themselves of this troublesome editor.”.

      • John permalink
        December 18, 2015 8:30 pm

        @Paul, that’s all fine and dandy. But still – why misrepresent this research? Why call it “published” when it’s not? Hell, undergrads present their baby projects as posters at the AGU. It’s not flattering to the significance of this work to over-sex and over-sell a poster presentation.

        The paper is the real deal and I’m super excited to see that that project is alive and well! But this poster isn’t the paper and shouldn’t be defended as such.

      • December 18, 2015 9:23 pm

        The AGU press release was not specific about whether it was “published” or not, and I scheduled for posting before Anthony ran his own post.(And I have clarified my post)

        But please don’t misrepresent this by calling Anthony’s effort a “poster”. It is nothing of the sort, as I suspect you know. It is a proper paper, that even arch warmist John Nielson-Gammon has been involved with.

        I still cannot understand why you don’t want others to hear what the AGU themselves have publicised in their Press Release, which is exactly what I have posted

        What is it you are trying to hide?

    • December 18, 2015 9:01 am

      Would you like more gravy?

      • December 18, 2015 2:37 pm

        Calm down John, everyone knows the difference between “published” and “submitted” and no one said it was published. So where is the BS in this thread?

      • John permalink
        December 18, 2015 8:32 pm

        @David, the original article started,

        “A paper has been published…”

        It has been edited to say, “submitted.” And no, not everyone understand how scientific literature is published and the process involved, so misrepresenting the stage of the process is not kosher.

      • December 18, 2015 9:27 pm

        The AGU Press Release did not specify that it was “submitted” rather than “published”, so please stop splitting hairs.

        Clearly you have some ulterior motive for not wanting people to see this study. What might that be?

    • S Allnutt permalink
      December 18, 2015 5:48 pm

      There have been many seminal papers in Physics which have not been peer reviewed.

    • miket permalink
      December 18, 2015 8:00 pm

      As Paul says, this is a hugely important paper That involved many people going to a lot of trouble to help. Of course you have waited a long time (and will continue to do so for a while longer) for a peer reviewed paper. This is because we have all been aware of the project from its very earliest beginnings. Other papers appear overnight as their publications are the first we know about them. Take a step back and try looking at the information with an open mind.

      But don’t ask him for the data and workings until publication, he has been burnt twice already by pre-publication to “trusted” persons.

  4. December 18, 2015 5:27 am

    Reblogged this on Climatism and commented:
    After all the “homogenisation”, infilling, fraudulent adjustments by NOAA, that are currently being investigated by Congress, now this paper shows a 50% overestimation of temps?!

    Yet, they take no shame in marketing “The Hottest Year Ever” meme, which is an apparent rise from the previous record of 0.01C ! That’s some fine-line data tampering!

  5. December 18, 2015 9:25 am

    Reblogged this on WeatherAction News.

  6. ANH permalink
    December 18, 2015 10:10 am

    It should read ‘San Francisco’ rather than ‘San Franciso’ – at the top somewhere (in bold)

  7. December 19, 2015 2:07 pm

    When you look into the the records of well-sited stations, the lack of warming is obvious, as is the effect of adjustments. My study of USHCN stations meeting the CRN#1 standard is here, with supporting Excel workbooks:

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