Steve McIntyre found an error in the GISS temperature data for the US. The GISTEMP page says:

USHCN station records up to 1999 were replaced by a version of USHCN data with further corrections after an adjustment computed by comparing the common 1990-1999 period of the two data sets. (We wish to thank Stephen McIntyre for bringing to our attention that such an adjustment is necessary to prevent creating an artificial jump in year 2000.)

How much difference did the adjustment make to the US temperature series? Well, it changed this:

i-4c2bced67bf8018e653c78a3f2fd4553-gissusold.png

to this:

i-2c65826a3e6c732f35375023de42ebd2-gissusnew.png

Not much difference. The right hand end of the red curve has moved down a little bit, but this decade is still the warmest ever recorded in the US. The change to the global temperature series is imperceptible.

Of course, if you’re Steve McIntyre, you want to make this seem like a big deal. So what do you do?

Well, it’s hard to see from the graph, but 1998 went from being 0.01 degrees warmer than 1934 in the US, to being 0.02 degrees cooler, so he was able to present this as OMG! 1998 NO LONGER THE HOTTEST YEAR ON RECORD, NOW IT’S 1934. Right wing blogs started foaming at their mouths. Examples:

Noel Sheppard

it suggests that a government agency is actually participating in a fraud against the American people by withholding information crucial to a major policy issue now facing the nation.

Ace

Fire [James Hansen]. Immediately.

The Ace (This is a different person from “Ace” — I think we should pop “Ace” and “The Ace” into Thunderdome.)

leftist hero James Hansen is behind this deliberate fraud. He should be frog-marched out of his office.

Rush Limbaugh:

And the bottom line is, that 1998 is no longer — you can say NASA made a reporting error or did they make a reporting error? Did they do this on purpose? How long have they known that it was erroneous and haven’t corrected it? But the bottom line of this is that 1998 is no longer the hottest year on record. … Well, when 1934 was the hottest year on record, and NASA may know about it and doesn’t correct the data, and when a guy named James Hansen involved in all this, who is a political activist, then you have to figure there is a reason why they want 1998 continue to be reported as the warmest year on record.

I’ll let Nexus explain this one for Mr Limbaugh.

Also busy exaggerating is good old Roger Pielke Sr:

The hard work of of Steve McIntyre (Climate Audit) and Anthony Watts (www.surfacestations.org) has resulted in the identification of a significant error in the assessment of the rankings of what have been the warmest years in the United States as identified by GISS. The current warmest year is 1934.

1998 and 1934 went from being in a virtual tie, to being in a virtual tie. This is not a significant change. You would have hoped that Pielke Sr would have been aware of this, but I guess not.

Oh, and I didn’t link to Climate Audit, because It’s gone down because of all the traffic from Limbaugh and the like. The paranoids there reckon it’s a DOS attack from the eevil warmers.

Update: More from RealClimate.

Comments

  1. #1 Lee
    August 31, 2007

    vernon, you are so full of crap.

    For starters, your url is broken. Not that it matters – I have that paper, have had for a long time, and have read it several times now. I jsut re-read it.

    You keep saying that this mythical ‘urban offset’ is applied to all stations in the network. In section 4.2.1 of Hansen et al 2001, on page 5, they say (emphasis added):

    “.. the long-term temperature trends of the periurban and urban stations are adjusted to match the mean trend of neighboring unlit stations.”

    IOW, rural stations are not given any “UHI offset” and all other stations are adjusted such that their trend (TREND, vernon, not temperature) matches that of the unlit stations in the US, or rural stations based on pop in the rest of the world.

    You also give a perfectly absurd description of some imaginary process that you want us to believe is what Hansen did – that he simply subtracted “rural” from “urban”. Notably, despite many requests to do so, you do not define what precisely he is subtracting (in your mind). Populations? Surface areas? annual rainfall? Temperatures? (one more time, vernon – no it isn’t temperatures. It isn’t even subtraction).

    Vernon, he did not simply “subtract” anything from anything to make the UHI adjustment. Here is the description of what they do, in 4.2.2 of the paper:

    4.2.2 Urban Adjustment. In the prior GISS analysis the time series for temperature change at an urban station was adjusted such that the temperature trends prior to 1950 and after 1050 were the same as the mean trends for all “rural” stations (population less than 10,000) located within 1000km. (with the rural stations weighted inversely with distance). In other words, it was a two-legged adjustment with the two legs hinged at 1950 and with the slopes of its two lines chosen to minimize the mean square difference between the adjusted urban record and the mean of its rural neighbors.
    The urban adjustment in the current GISS analysis is a similar two-legged adjustment, but the date of the hinge point is no longer fixed at 1950, the maximum distance used for rural neighbors is 500km provided that sufficient stations are available, and the “small-town” population 10,000 to 50,000) stations are also adjusted. The hinge date is now chosen to minimize the difference between the adjusted urban record and the mean of its neighbors. In the US (and nearby Canada and Mexico regions) the rural stations are now those that are “unlit” in satellite data, but in the rest of the world, rural stations are still defined to be places with population less than 10,000. The added flexibility in the hinge point allows more realistic local adjustments, as the initiation of significant urban growth occurred at different times in different parts of the world.”

    So, vernon, you adamantly declared that the adjustment was made prior to determining trends. This is false – they make the adjustment specifically by adjusting the urban trend so as to minimize the mean square difference between rural and urban trend. Not only that, they do a two-legged trend adjustment, with a floating hinge, to accommodate urban areas that have shown rapid recent growth.

    How in all hells you get from that to saying that they simply ‘subtract rural from urban’ is utterly beyond me. Oh, wait – do you think that “mean square difference” is simply subtraction? Really?

    You also say they make the adjustment in grid cells. No, they look at each individual station, find the nearest neighboring rural stations, weight by distance from the urban station, and then adjust the trend for each individual urban station. Gridding is done AFTER the adjustments are made.

    And again, the Phoenix paper you cite is utterly irrelevant. That paper looks at effects on the measured temperature based on where in an urban area you put the station. For trends (and they are working with trends, vernon – read the damn paper. Oh, you already did – learn to read, vernon) for trends it doesn’t matter if the station is in a site that is 3C warmer than if it was placed somewhere else.

    Now, if you are going to continue to so adamantly and repeatedly insist that you know better than everyone else what is happening, could you at least try to get the simple, basic description-of-what-they-did stuff at least somewhere on the same planet as reality?

  2. #2 dhogaza
    August 31, 2007

    What do you do here, sit around chanting to Gaia and ignore any thing that does not agree with your dogma?

    Talk about the pot calling the kettle black …

  3. #3 Vernon
    September 1, 2007

    Well, Lee, lets see what you had to say about my argument, facts and logic.

    First, ‘vernon, you are so full of crap.’ does not address either the facts or the logic of my argument.

    I guess you concede the following since you do not address this part of my argument:

    Hansen (2001) states quite plainly that he depends on the accuracy of the station data for the accuracy of his UHI off-set.

    WMO/NOAA/NWS have siting standards

    Surfacestations.org’s census is showing (based on where they are at now in the census) that a significant number of stations fail to meet WMO/NOAA/NWS standards.

    Hansen uses lights=0 in his 2001 study

    Due to failure of stations to meet siting standards, lights=0 does not always put the station in a accurate rural environment.

    At this time there is no way to determine the accuracy of Hansen’s UHI off-set

    Any GCM that uses this off-set has no way to determine the accuracy of the product being produced.

    You do not address any of these points. You do pull out the ever popular red herring to drag around.

    You say:

    You keep saying that this mythical ‘urban offset’ is applied to all stations in the network. In section 4.2.1 of Hansen et al 2001, on page 5, they say (emphasis added):

    “.. the long-term temperature trends of the periurban and urban stations are adjusted to match the mean trend of neighboring unlit stations.”

    IOW, rural stations are not given any “UHI offset” and all other stations are adjusted such that their trend (TREND, vernon, not temperature) matches that of the unlit stations in the US, or rural stations based on pop in the rest of the world.

    Odd, but I did not discuss how GISSTEMP used the adjustments so I have no way of knowing what argument you’re addressing. It is not anything I have as part of my argument.

    You then go on to demonstrate completely how little you know about this subject when you say:

    You also give a perfectly absurd description of some imaginary process that you want us to believe is what Hansen did – that he simply subtracted “rural” from “urban”. Notably, despite many requests to do so, you do not define what precisely he is subtracting (in your mind). Populations? Surface areas? annual rainfall? Temperatures? (one more time, vernon – no it isn’t temperatures. It isn’t even subtraction).

    Lee, you still have not disproved my facts or my argument. Whether I am right or wrong on how Hansen uses the lights = 0 stations, and I believe I am correct. He did the stations with a gird cell, otherwise, he would not be able to get regional adjustments.

    So, vernon, you adamantly declared that the adjustment was made prior to determining trends. This is false – they make the adjustment specifically by adjusting the urban trend so as to minimize the mean square difference between rural and urban trend. Not only that, they do a two-legged trend adjustment, with a floating hinge, to accommodate urban areas that have shown rapid recent growth.

    Where do you get this from? I said that prior to GISSTEMP determining trends, Hansen’s adjustments, one of which is the UHI off-set is applied. Gavin agrees that that is the way it is done by GISSTEMP. This is discussing how Hansen (2001) is used, not how Hansen (2001) was created at this point.

    You went on to say:

    How in all hells you get from that to saying that they simply ‘subtract rural from urban’ is utterly beyond me. Oh, wait – do you think that “mean square difference” is simply subtraction? Really?

    You also say they make the adjustment in grid cells. No, they look at each individual station, find the nearest neighboring rural stations, weight by distance from the urban station, and then adjust the trend for each individual urban station. Gridding is done AFTER the adjustments are made.

    Well, again, another red herring. The most basic step in the process is subtracting the rural from the urban to get a difference. What matters are the rural stations which Hansen tries to do locally, within the grid cell, and there is not enough within the cell, he goes to adjacent cells.

    Then you go on to say :

    And again, the Phoenix paper you cite is utterly irrelevant. That paper looks at effects on the measured temperature based on where in an urban area you put the station. For trends (and they are working with trends, vernon – read the damn paper. Oh, you already did – learn to read, vernon) for trends it doesn’t matter if the station is in a site that is 3C warmer than if it was placed somewhere else.

    Wrong, wrong, wrong. The Phoenix paper talks about the actual measured temperature based in where the instruments are sited. They show that where a station is sited can cause between 1 – 5 degrees C change in the measured temperature. That, if you had the intelligence to understand my argument, matters. Where the rural sites are placed can interject 1 -5 degrees C error. Hansen’s two assumptions are that the station data is accurate, and a 1 – 5 degree error due to not meeting site guidance refutes that, and that there is less than a few hundreds degree C change in the rural stations due to human influence, which also is false due to failure to meet site guidance. Surfacestations.org’s census is proving that a significant number of stations do not meet Hansen’s requirements but at the time Hansen used them assuming that they would.

    Hansen makes two assumptions which I can show are not true. I do not think it makes me smarter than most people, but it seems like the true believers would rather live the lie than say ‘that could be a problem, lets find out what the answer really is.’

    by the way Lee, what do you think a trend is? Why if all Hansen did was impose a rural trend on the urban, did he bother to keep the urban since the trend was from the rural? Why not just use the rural… oh wait, that is what CRN is doing and if you do that you do not get the accerated warming.

  4. #4 Lee
    September 1, 2007

    vernon,

    THERE IS NO FUCKING UHI OFFSET!!!!!

    You keep claiming some such thing, and talking about how it is derived by “subtracting rural from urban.”

    What there is, is an adjustment of the TREND.

    I not only cited, I QUOTED FOR YOU the section of Hansen 2001 where he describes what he does to adjust the urban stations. There is NOTHING in there that matches what you are claiming. You keep claiming that the first step is a “UHI offset” that does not involve trends, and THERE IS NO WHERE THAT HANSEN DESCRIBES SUCH A STEP. There is no subtraction step such as you describe.

    I am responding directly to your argument, vernon. I am poimting out that your argument is based on imaginary shit that does not match what is being done, and I am showing you directly from the paper you yourself cite what is actually being done.

    And I’m finished with you. Ive given you chance after chance to support the statement yo are making , whnile pointing out that the paper you cite says somethig completely different. Yo are either dishonest, or one of the most deeply stupid people I’ve ever met. either way, enough.

  5. #5 Bosco
    July 3, 2008

    Let me get this straight, if one says 1998 is NOT the hottest year on record it’s a rightwing rant about nothing. If though it’s reported as the hottest year on record, OMG the world as we know it is ending, see I told you so, we’re right and your wrong, let’s spend trillions on it, that is ideologically, politically, neutral speak. Otay Buckweeet.