Friday, March 10, 2017

January HADCRUT and David Rose.

Yet another episode in the lamentable veracity of David Rose and the Daily Mail. Sou covered a kerfuffle last month when Rose proclaimed in the Sunday Mail:

"The ‘pause’ is clearly visible in the Met Office’s ‘HadCRUT 4’ climate dataset, calculated independently of NOAA.
Since record highs caused last year by an ‘el Nino’ sea-warming event in the Pacific, HadCRUT 4 has fallen by more than half a degree Celsius, and its value for the world average temperature in January 2017 was about the same as January 1998."


This caused John Kennedy, of the Met Office, to note drily:



Rose was writing 19 Feb, and Hadcrut does indeed take much longer to come out. But it is there now, and was 0.741°C for the month. That was up quite a lot from December, in line with GISS (and Moyhu TempLS). It was a lot warmer than January 1998, at 0.495°C. And down just 0.33°C from the peak in Feb 2016.

And of course it was only last December that David Rose was telling us importantly that "New official data issued by the Met Office confirms that world average temperatures have plummeted since the middle of the year at a faster and steeper rate than at any time in the recent past".

In fact, January was warmer than any month since April 2016, except for August at 0.77°C.

Update. David Rose was echoed by GWPF, who helpfully provided this graph, sourced to Met Office, no less:

I've added a circle with red line to show where January 2017 actually came in. I don't know where their final red dot could have come from. Even November, the coldest month of the 2016, was 0.524°C, still warmer that Jan 1998.

14 comments:

  1. Replies
    1. Yes, after 2016 and the outlier peak of Jan 2007.

      Delete
  2. Pretty slimy. The fact that they are lying is not in dispute, I just wonder how they reconcile that with their own ethics?

    I think the red dots are the temps for January in other years, they have cherry-picked the years to suit to distract from the overall trend.

    ReplyDelete
  3. Looking for simplest dumb thing they might have done: looks like the January 2017 dot is from HadSST3, which gets reported earlier than HadCRUT4.

    ReplyDelete
    Replies
    1. Yes, that seems to be Tim Osborn's view (Mar 8), though he mentions February, not Jan.

      Delete
    2. Yes, I think it seems likely that GWPF/Rose appended the Jan HadSST value onto the end of the HadCRUT global temperature series by mistake. GWPF made the error first on 15 Feb, posted it and tweeted it. I told them that Jan HadCRUT value wasn't out. They didn't issue a correction and Rose repeated their error on 19 Feb.

      My later tweet mentioning February was when Feb HadSST value came out, encouraging GWPF not to make the same mistake again.

      Delete
    3. Tim Osborn,
      Thanks for clarifying.

      Delete
  4. Would't the appropriate comparison be to January 1999, since that's the post-nino January?

    cabc

    ReplyDelete
    Replies
    1. My opinion is there are no valid comparison points with noisy monthly data. Taking an annual average improves comparisons a bit because it eliminates some of the yearly season cycle. Annual is still not good enough for some, they prefer decadal averages.

      Delete
    2. I tried January 1999 as an intellectual exercise. I used the correct data as explained in the article, not the data David Rose made up.

      Monthly data:

      http://www.woodfortrees.org/plot/hadcrut4gl/from:1999.08/to:2017.08/compress:1/plot/hadcrut4gl/from:1999.08/to:2017.08/trend

      12 month average data (which reduces noise). From this graph it is reasonable to (naively) conclude the "pause" finished in 2012...

      http://www.woodfortrees.org/plot/hadcrut4gl/from:1999.08/to:2017.08/compress:12/plot/hadcrut4gl/from:1999.08/to:2017.08/trend

      Delete
    3. I agree with Harry that no two months over any span of years are directly comparable, because month-month variance (due to what we call "weather") is too high. But major El Nino events run on a fairly predictable time scale once they start: They tend to peak late in the year (around Nov) and the global surface temps tend to follow with a lag of 3-4 months, thus peaking Feb-April in the following year (usually as the El Nino itself is breaking down). In the case of the '97-98 El Nino, the January 1998 temperature was plum in the middle of the rising phase of the peak, and thus more directly comparable to January 2016, NOT 2017! We should be comparing Jan 2017 with 1999, when the El Nino had broken down and the world was responding to the well developed La Nina.

      Of course that comparison is also unfair, given that the 2016 La Nina was a fizzer and is now replaced by neutral conditions. This is of course why we should ignore the peaks and troughs and plot trends over longer time frames. It doesn't matter which data set you use, those trends are significantly upwards.

      Delete
  5. Nick, Since you are amending their graph to add the real Jan 2017 point, could you please also add a a red circle to Jan 1999 so that we can compare things a little more reasonably: i.e. the Januarys AFTER the year of the El Nino peaks!

    ReplyDelete
    Replies
    1. dave,
      I'm not using any facny graphics here, just by eye. And there isn't much x-axis info to work with. The level at Jan 1999 was 0.347°C. The bottom lines mark 0.2 and 0.4.

      Delete