Roy Spencer hides the increase

Possum Comitatus has noticed a very interesting change in Roy Spencer’s presentation of his satelite temperature data.

This is the November version:


And this is the December version:


Spot the difference!

Update: Gavin reminds me that in April Spencer was using a ridiculous degree 4 fit to the data:


If he’d stuck with that, the current graph would look like this:


The polynomial is still decreasing at the end, but the divergence from the data is striking.


  1. #1 P. Lewis
    October 7, 2010

    Doesn’t that Sept 2010 figure now take his current 13-month moving average to above the 1998 13-month moving average?

    Time for a new average? Something on the order of 60 months might bring it back down to a more acceptable level, don’t you think?

  2. #2 Tim Lambert
    October 7, 2010

    Yes, the Sep 2010 figure sets a record high for the 13 month moving average. The 25 month one is even worse for Spencer now – it reached a record high in July which was broken in August and again in September.

  3. #3 Shinsko
    February 4, 2011

    Just looking at [Spencer’s site]( – has he just changed the baseline too?

  4. #4 Tim Lambert
    February 4, 2011

    Yes. He’s now using a 30 year baseline.