HadISST Historical Arctic Sea Ice Concentration Data

Commenter Henry P over on “Steve Goddard’s” (un)Real Science blog poses the following question:

Unfortunately, we do not have any record of ice around 1929. But there was an eyewitness report of the melting of ice around 1923. Noting that Antarctic ice is currently increasing, my question to you Jim is simply this: why do you think that Arctic melt now is more than 87 years ago?

By way of a partial answer to that question, the United Kingdom’s Meteorological Office (Met Office or UKMO for short) maintains the Hadley Centre Sea Ice and Sea Surface Temperature data set (HadISST for short). Unfortunately Henry P is obviously sadly misinformed, since according to the Met Office:

HadISST is a unique combination of monthly globally-complete fields of SST and sea ice concentration on a 1 degree latitude-longitude grid from 1870 to date.

Here is what the HadISST data set reveals for September 1929:


compared to September 2015:


Surely a working pair of Mark 1 eyeballs should be sufficient to allow even a dyed in the wool denizen of (un)Real Science to spot the difference?

11 thoughts on “HadISST Historical Arctic Sea Ice Concentration Data

  1. Henry,

    The truth as it is. You said:

    We do not have any record of ice around 1929.

    Yes we do. see above. You then said:

    I think all they did is to backtrack the current trend to what they think it must have been, from the current [linear] trend that they observed.

    In answer to which I said:

    I take it you didn’t bother to read the Met Office’s recommended introduction to their data set?

    You then said:

    So? It is exactly like I said. …. Your observations are based on back interpolations of current data (from 1981).

    I’ll quote from the Met Office HadISST paper:

    Digitized Sea Ice Charts

    This subsection details the data originally derived from hand-drawn charts. In some cases these charts were simply ice extents, in others some information about sea ice concentration was also available.

    I take it you didn’t bother to read the Met Office’s recommended introduction to their data set particularly carefully?

  2. It has recently become all too apparent that Anthony Watts is an avid reader of the Great White Con blog. He has even been known to plagiarise portions!

    Now comes news of prima facie evidence that his chum Willis Eschenbach has been closely studying this very article! If you don’t believe me take a look at:

    The Awful Terrible Horrible Global Sea Ice Crisis

    I cannot help but wonder if Willis has ever tried doing an Arctic only analysis of the HadISST data:


    I also cannot help but wonder if he will ever receive my message in a WUWT bottle!

    1. Didja ever wonder if Watts/Willis et al, ad nauseam, will ever give up, and admit how wrong they have been?


    2. Congratulations with regards to your teaming up with Eli, that must raise the blood pressure of the chubby college drop out and failed weatherman. Add to that the fact that Sou gets praised at Climate Crocks and Neven’s CC shout out, it was indeed an unpleasant week for Willard.
      Reggie believes that Saul from Montreal is a card carrying member of JREF but has no idea about Eternal Optimist. Strange coincidence…SFM and EO both posted comments at the exact same minute and R believes they are not the same person. If it is true that JREF is involved, the future for Watts looks bleak.
      Reggie attempted to contact SFM using your method and is waiting for a reply.
      Over at the forum Neven posted a comment regarding a torch, that made me smile.

      1. Why indeed? Perhaps Bill is guilty merely by his association with Neven and/or Snow White?

        What do you suppose would happen should Snow White kiss that frog?

  3. I blame Neven because it took only a one sentence comment which had the good fortune to be the very first of a thread that now lives in infamy and make #WUWT look like a moron.

    Of course I am not blameless and confess that I am the notorious victorious Master of Space and Thyme…

    Who called Watts at 3am to tip him off regarding our comments at Curry’s blog…Smokey?

    Are you following Saul from #JREF?

    1. “Curiouser and curiouser!” cried Alice, once again.

      Neven and I have crossed swords with “Javier” on this self same topic before, over at Clive Best’s establishment:

      It seems Willis n Watts are perfectly happy to allow him to link to an old article by Diablo on this subject:


      and post this old graph by Diablo:


      However when poor Bill mentions Diablo’s latest work he is banished into the outer darkness for all eternity. Perhaps Watts has an irrational fear of fairy tales that are not of his own making? And why doesn’t Javier mention Diablo’s more recent work, since he’s obviously well aware of it?

      The #SnipGate story gets ever more surreal with each passing day!

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