2011-07-12 01:24:14More denier predictions discussed at Real Climate
Tom Curtis




While not perfect, the Independent graphic is shown to have been pretty good – especially for a hand-drawn schematic, while the more dramatic implications from McIntyre or Pielke were large overestimates (as is often the case). The impact on trends is maximised for trends starting in 1946 (a 21% drop in the 1946-2006 case), but are smaller for the 1956-2006 trend (11% decrease from 0.127±0.02 to 0.113±0.02 ºC/decade) (the 50 year period highlighted in IPCC AR4). More recent trends (i.e. 1970 or 1975 onwards) or much longer trends (1900 for instance) are barely changed. For reference, the 1950-2006 trend changes from 0.11±0.02 to 0.09±0.02 ºC/decade – a 17% drop in line with what was inferred from the Independent graphic. Note that while the changes appear to lie within the uncertainties quoted, those uncertainties are related solely to the fitting of an regression line and have nothing to do with structural problems and so aren’t really commensurate. The final analysis will probably show slightly smaller changes because of the coverage/sea ice issues. Needless to say the 50% or 30% reductions in trends that so excited the bloggers did not materialize.


2011-07-12 01:58:30
Dana Nuccitelli

It would be good to do an evaluation like this for McIntyre's prediction as part of the Lessons from Past Climate Predictions series, but we should wait until HadCRUT3 is updated in order to make a more accurate assessment.

2011-07-12 04:47:46


Actually it was not a prediction, just an inflated adjustment to real data.

2011-07-12 05:06:59
Dana Nuccitelli

Well, it was a prediction regarding what the adjustment would look like.  It might be worth examining why McIntyre's adjustment prediction was so wrong (Gavin mentioned one or two reasons in his RC post).

2011-07-12 08:55:36


I went a bit nutty in the comment section -- hohoho

2011-07-12 11:57:01Prediction series
John Cook


Whether we blog on this would depend on why McIntyre went wrong. If it's some obscure data analysis method like conflating ocean temperature with global temperature, well, is it that big a deal? I would question whether it's worth doing when the core message of the Prediction series is "Predictions need to be based on physics" - this just seems like an opportunity to mock McIntyre (which I'm sure is pretty fun but not that constructive and doesn't really achieve the message we're trying to get across).