In this paper, we assess the reliability of such reconstructions and their statistical significance against various null models.

…

We propose our own reconstruction of Northern Hemisphere average annual land temperature over the last millenium, assess its reliability, and compare it to those from the climate science literature.

I have not had the time to look at the results in sufficient detail to pass judgment on the appropriateness of their approach, but, despite Steve’s (and my) aversion to Mann’s proclivity to devise new methods, would you not think that statisticians writing in a statistics journal might not be held to quite the same limits? From what I have seen it is not as much “new” methodology as opposed to previously developed statistical methods being applied in a new environment.

I think it will be interesting to see what commentary will appear with the article and who that commentary will come from.

On this blog, Steve has had many posts arguing against the way Mann introduces new methods without spending an appropriate amount of time explaining why the new method is better than any other method. If you are arguing that their goal was to introduce a new method, then it seems like they went about it the wrong way.

http://climateaudit.org/2008/04/23/univariate-calibration/

In my book, “has not been used” and “should not have been used” do not have the same meaning. New ways of looking at things can often provide better insight than arguing the old methods.

So this example seem to be deriving CO2 sensitivity not from temperature but from CO2 concentration. So CO2 derives CO2. Isn’t the example just predicting CO concentration from CO2 concentration plus some noise? In regard to temperature, isn’t the example just assuming the conclusion that CO2 CONCENTRATION IS A LINEAR PREDICTOR OF TEMPERATURE?

At the Air Vent, Jeff Id has used pseudoproxies with low S/N ratios to show convincingly that it is possible to extract signal in the presence of a lot of noise. The AGW Consensus paleoclimate reconstructors shouldn’t be faulted for working with low-signal proxies… since that’s the only type that exist.

Mann08′s screening was set up in a way that allowed the Tiljander series (plural) to pass. This illustrates some of the flaws in the AGW Consensus’ implementation of the “proxy” idea, which I have come to think of as the Proxyhopper approach — “if they look plausible, toss ‘em in, the algorithm will take care of any difficulties.”

The pitfalls of setting out to look for the kind of data that you’d like to find have been discussed at length, and are well-understood in many fields,, e.g. in clinical trial design. That Mann08′s employment of the Tiljander series continues to be defended by AGW Consensus scientists is evidence that this basic point is still not grasped.