Global Warming: Climate Gate – Mann’s Hockey Stick Findings Refuted – Irrelevant To Accurate Warming Predictions – Annals of Applied Statistics

From:

Watts Up With That? –  New paper makes a hockey “sticky wicket” of Mann et al 98/99/08

Sticky Wicket – phrase, meaning: “A difficult situation”.

http://wattsupwiththat.com/2010/08/17/breaking-new-paper-makes-a-hockey-sticky-wicket-of-mann-et-al-99/

Now, there’s a new look to the familiar “hockey stick”.

The “infamous Hockey Stick” below:

Multiproxy reconstruction of Northern Hemisphere surface temperature variations over the past millennium (blue), along with 50-year average (black), a measure of the statistical uncertainty associated with the reconstruction (gray), and instrumental surface temperature data for the last 150 years (red), based on the work by Mann et al. (1999). This figure has sometimes been referred to as the hockey stick. Source: IPCC (2001).

McShane and Wyner re-examine and replot the data below …

Backcast from Bayesian Model of Section 5. CRU Northern Hemisphere annual mean land temperature is given by the thin black line and a smoothed version is given by the thick black line. The forecast is given by the thin red line and a smoothed version is given by the thick red line. The model is fit on 1850-1998 AD and backcasts 998-1849 AD. The cyan region indicates uncertainty due to t, the green region indicates uncertainty due to β, and the gray region indicates total uncertainty.

“Not only are the results stunning, but the paper is highly readable, written in a sensible style that most laymen can absorb, even if they don’t understand some of the finer points of bayesian and loess filters, or principal components. Not only that, this paper is a confirmation of McIntyre and McKitrick’s work, with a strong nod to Wegman. I highly recommend reading this and distributing this story widely.”

http://wattsupwiththat.com/2010/08/17/breaking-new-paper-makes-a-hockey-sticky-wicket-of-mann-et-al-99/

The original paper submitted by McShane and Wyner to Annals of Applied Statistics here: A Statistical Analysis of Multiple Temperature Proxies: Are Reconstructions of Surface Temperatures Over the Last 1000 Years Reliable?

EXCERPT:

On the one hand, we conclude unequivocally that the evidence for a ”long-handled” hockey stick (where the shaft of the hockey stick extends to the year 1000 AD) is lacking in the data … Consequently, the long flat handle of the hockey stick is best understood to be a feature of regression and less a reflection of our knowledge of the truth… Climate scientists have greatly underestimated the uncertainty of proxy based reconstructions and hence have been overconfident in their models…  

One Response

  1. Greedy liars never quit, do they? Always some slimy angle to armchair quarterback the real scientists’ work.

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