[asa] Re: The Hockey Stick Holds Up

From: j burg <hossradbourne@gmail.com>
Date: Wed Sep 10 2008 - 14:06:52 EDT

On page 293 ff of PHYSICS FOR FUTURE PRESIDENTS, Muller argues that
the "hockey stick" graph is fundementally flawed. Does this latest
refute his arguments?


On 9/10/08, Rich Blinne <rich.blinne@gmail.com> wrote:
> From today's Nature. Climate change: 'Hockey stick' holds up
> *Proc. Natl Acad. Sci. USA* *105*, 1325213257
> (2008)<http://www.pnas.org/content/early/2008/09/02/0805721105.abstract>
> A fresh analysis of climate indicators shows that the Northern Hemisphere
> is
> warmer now than it has been in at least 1,300 years.
> Previous analyses of climatic history by Michael Mann of Pennsylvania State
> University in University Park and his colleagues produced a distinctive
> 'hockey stick' shape; but some of this analysis, and the tree-ring data it
> used, came under attack.
> The latest work by Mann and his co-workers involves various climate
> proxies,
> including corals, ice cores, historical records and marine sediments. The
> authors show that current warming is anomalous even if all tree-ring data
> are eschewed.
> The URL to the study is here: http://www.pnas.org/content/105/36/13252.full
> Note: that when statements such as "in at least 1,300 years" are used it
> ONLY means that the data is reliable through that period and not that it
> was
> warmer 1,300 years ago. If the tree ring data is included that number goes
> back 1700 years (and there is still nothing warming than the current period
> as far back as the data sees). The data noted here also includes the
> so-called Medieval Warm Period. The current study gives a slightly warmer
> reading but it is WAY cooler than present.
> The graph in the study can be found here:
> http://www.pnas.org/content/105/36/13252/F3.large.jpg
> EIV stands for error in variables and is the new technique that increases
> the accuracy of the analysis versus CPS (composite plus scale) because it
> deals with errors both in the predictor and predictand.
> Rich Blinne
> Member ASA

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Received on Wed Sep 10 14:07:05 2008

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