date: Fri Sep 23 10:55:40 2005 from: Tim Osborn subject: Re: Fwd: McIntyre Jones and Briffa to: Keith Briffa , p.jones@uea.ac.uk, t.m.melvin@uea.ac.uk David and I were just doing a quick search for "briffa error" on google and it came up with this page: [1]http://www.climateaudit.org/?p=159 with discussion of modern sample bias and a link to Tom's PhD thesis, plus quotes from it, etc. They may well have got some of the ideas in the abstract below from Tom's thesis! Hopefully nobody will preempt your papers on standardisation and bias. Cheers Tim At 13:19 22/09/2005, Keith Briffa wrote: Keith, found this posting on McIntyre´s blog. Something in the making, just to warn you if you did not see it yet. Cheers Eystein 9/16/2005 U.S. climate change Science Program Workshop I've had an abstract accepted for the U.S. Climate Change Science Program (CCSP) Workshop, "Climate Science in Support of Decisionmaking," to be held November 14-16, 2005. My abstract is entitled: "More on Hockey Sticks: the Case of Jones et al [1998]". The workshop is described here. Here is my abstract (which moves on from MBH): More on Hockey Sticks: the Case of Jones et al [1998] Abstract. Multiproxy studies purporting to show 20th century uniqueness have been applied by policymakers, but they have received remarkably little independent critical analysis. Jones et al. [1998] is a prominent multi-proxy study used by IPCC [2001] and others to affirm the hockey stick shaped temperature reconstruction of Mann et al. [1998]. However, the reconstruction of Jones et al. [1998] is based on only 3-4 proxies in the controversial Medieval Warm Period, including non-arms-length studies by Briffa et al. [1992] and Briffa et al [1995]. We show that the Polar Urals data set in Briffa et al [1992] fails to meet a variety of quality control standards, both in replication and crossdating. The conclusion of Briffa et al. [1995] that 1032 was the "coldest year" of the millennium proves to be based on inadequate replication of only 3 tree ring cores, of which at least 2 are almost certainly incorrectly crossdated. We show that an ad hoc adjustment to the Tornetrask data set in Briffa et al [1992] cannot be justified. The individual and combined impact of defects in the Polar Urals data set and Tornetrask adjustments on the reconstruction of Jones et al [1998] is substantial and can be seen to have the effect of modifying what would otherwise indicate a pronounced Medieval Warm Period in the proxy reconstruction. Inhomogeneity problems in the Polar Urals and Tornetrask data sets, pertaining to altitude, minimum girth bias and pith centering bias will also be discussed.