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Monday, May 26, 2014

Gearing up for a hotter world at WUWT

Sou | 12:49 PM Go to the first of 13 comments. Add a comment


Over at WUWT the deniers are taking a deep breath and preparing themselves for a hotter year this year. Werner Brozek (Edited By Just The Facts) has a new article (archived here), warning WUWT-ers that if temperatures keep going along the lines of April, then this year could be up there with 2010 and 2005 as the hottest year on record - and this is before any El Niño has been declared.

It's a bit early to make any predictions. GISTemp for the first four months is trailing 2010 but has crept above 2005, as you can see from the chart below.

Data Source: NASA GISTemp


Werner's also observed what I noticed, that there have been a lot of new adjustments to GISTemp recently. Not just for the past twelve months but going back further in time. I haven't seen any explanation on the GISTemp website for the most recent changes yet. I expect it will come as they are usually quite diligent in giving explanations.

Some people are querying the changes as a conspiracy to make earlier records colder so that later records look warmer. However more recent records have been adjusted downwards and older records adjusted upwards. That will puzzle WUWT-ers no end. (If they follow the recursive fury pattern I expect they'll try to amend the conspiracy theory while keeping it to "nefarious intent" but it's hard to see how.)

Below is a chart showing the adjustments over time as the net adjustment for the year. I've compared the latest GISTemp data with that from the end of 2013, subtracting the older anomalies from the newer. That is, a positive value means that the latest GISTemp data has been adjusted up and a negative value means the data has been revised down.

You can see that most of the upward adjustments have been in earlier years, while in later years the anomalies have been adjusted down. All but a few this decade have a net effect of only 0.01 degrees in any year.

Data Source: NASA GISTemp


As for this year, April was a hot month and it looks to me that May has been a tad warm in some parts of the world. If El Niño emerges then that will only add to the trend.


From the WUWT comments


Scott Basinger gets it topsy turvy and says:
May 25, 2014 at 6:15 pm
Adjust the past down, adjust the present up. Look, a trend!


wbrozek says:
May 25, 2014 at 6:26 pm
Latitude says: May 25, 2014 at 6:08 pm
Thank you!
I can understand that there could possibly be good reasons why things could be adjusted from a hundred years ago, but why would 2010 be adjusted in the last 4 months? And why would the all time record month of January 2007 go down from 0.94 to 0.92 over the last 4 months?

Late arrival of data can lead to adjustments. But this looks to be more than that. Either GISTemp has had a big spring clean or the algorithm has been modified. Maybe I'll ask Gavin Schmidt.


Bill H says:
May 25, 2014 at 6:44 pm
One hundredth of a degree C… What instrument is so carefully calibrated and placed around the world so quickly that we are talking this small a change?
The more observations the better the precision can be. That's statistics.

13 comments :

  1. Here is a comment I posted at WUWT on the GISS changes:

    Here is the GISS log of changes. They record that:
    "January 21, 2014: The GISS analysis was repeated this morning based on today's status of the GHCN data. The changes were well within the margin of error, e.g. the L-OTI mean for 2013 changed from 0.6048+-0.02°C to 0.6065+-0.02°C, a change of less than 0.002°C. However, rounding to 2 digits for the L-OTI table changed the 0.60°C used in some documents prepared last week to 0.61°C. This minuscule change also moved year 2013 from a tie for the 7th place to a tie for the 6th place in the GISS ranking of warmest years, demonstrating how non-robust these rankings are."

    Clearly the changes in January reflect a catch-up to past changes in GHCN. GHCN changes as belated data comes in, and also if the adjustment algorithm changes. GISS now relies on the GHCN homogenization; they don't do their own

    ReplyDelete
  2. Thanks Nick. The recent changes are post January as far as I can make out and data going way back to the start of the records has changed a bit (see above chart).

    So from what you're saying, the GHCN homogenization has probably changed in the last month or so, but there's no word yet that I can see. Nothing since the February comment.

    ReplyDelete
    Replies
    1. Just to clarify, the 2013 GISTemp temp is now showing 0.59 not 0.61 (or 0.60) - for Jan-Dec, so there have been further adjustments since that note from January.

      Delete
    2. Sou,
      I think the main reason for change with 2013 is late data, and also flaky data that gets fixed. There has been a lot of flakiness lately. Here is a study of how data trickled in with v2.

      I think what happens with flaky data is that it gets reasonably treated by homogenisation, but if the original error gets fixed, then that's another change.

      However, I haven't seen a lot of fixing in GHCN lately.

      Delete
    3. Thanks, Nick. Yes 2013 data adjustments make sense and happens fairly often. It's the fact that there were changes going back to year one (1880) that made me wonder if a new algorithm was being used. I've not seen so many records changed before (818 changes from 1880 through to 2013).

      Delete
  3. Does this help at all?

    ReplyDelete
  4. Makes it a bit easier to set a new "all time high" when you wash away some of the heat from the previous all time high.

    ReplyDelete
    Replies
    1. Premature denial - definitely signs of nerves.

      Delete
    2. So Skeptikal,

      You obviously missed the graph above where it is clearly shown that the adjustments of recent years have mostly been downwards?

      Not very "sceptical" are you?

      Delete
    3. The poor man is clearly rattled by the chance that a new all time high might be set. After all, this shouldn't be possible if you believed all that crap about the planet cooling since 1998. Still, I am sure that our unsceptical friends will be issued with a new set of nonsense to parrot very shortly: "no warming since 2015, squawk, squawk".

      Delete
    4. Skeptical

      Do you actually believe that what you posted has any validity? Or are you just having a laugh and trying to wind people up? I am just interested.

      If you do believe it is valid please give us a description of your calculations to support it.

      Thanks.



      Delete
  5. Just as an aside:

    Wattmeter idjit output at a glance:

    grant climate cagw
    POWER
    citizen government
    MONEY
    control agenda
    LEFT mann
    dbstealey science alarmists


    It seems to be working...

    ReplyDelete
  6. phil hansen is clearly doing cooling adjustments to confuse us. He probably heard us point out that his adjustments are always up so he thought he'd quickly throw in some minor cooling adjustments.

    ReplyDelete

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