William Connolley is still, shall we say, manfully pretending not to understand how sediments affected by bridge-building, ditches and agriculturally activity cannot be excellent temperature “proxies” if they correlate with NH temperature.
Amazingly, some of his readers, like PNAS editors and referees, take this sort of stuff seriously.
Just for fun, I’ve constructed an example that, IMO, contains the relevant features of the Tiljander example, combining a well known series with “rank Gavin noise”, defined here as two times log(1000) minus the log of the rank of Gavin among US names (somewhat modifying realclimate’s Gavin index, originally proposed by Lucia.)
As you see, it has a familiar hockey stick shape. It has an excellent correlation (.81; r2: 0.65) with HadCRU global temperature during the “calibration period” of 1954-2008 when Gavin ranks are available here .
Readers are invited to identify the mystery proxy – which shouldn’t be too hard for CA readers.
While the example is constructed to be amusing, there is a fundamental point here – in general, Team methodologies assert without ever providing proof that “proxies” are a combination of “true temperature” plus white noise or low-order red noise.
The metaphor – and it is a metaphor – of “signal” and “noise” for sediment or tree ring series is one that troubles me and many other statistically oriented CA readers, however climate scientists to date have been totally unmoved by such concerns, seemingly having trouble understanding such elementary things as Mann’s misuse of the Tiljander series.
Obviously there’s a communications gap; maybe adding the concept of “rank Gavin noise” to noise repertoires of climate scientists will help bridge this gap.