Presentation on theme: "1 Presentation to the Subcommittee on Oversight and Investigations of the House Energy and Commerce Committee. Stephen McIntyre Toronto Ontario Washington."— Presentation transcript:
1 Presentation to the Subcommittee on Oversight and Investigations of the House Energy and Commerce Committee. Stephen McIntyre Toronto Ontario Washington DC, July 19, 2006.
2 NAS Panel Recommendation on Bristlecones Affects MBH Figure 1. MBH99 reconstruction and estimate of MBH99-type reconstruction without bristlecones. 20-year gaussian smooth.
3 Up-to-date temperature data from Sierra Nevadas shows no correlation of key MBH PC indicator to temperature Left - location of foxtail and bristlecone sites in the Sierra Nevada and White Mountains, California. Sheep Mountain is denoted SHP. Right - Black – annual mean of maximum and minimum temperatures (data, Christy, pers. comm.); red – MBH98 NOAMER PC1.
4 MWP annual minimum temperature in the California Sierra Nevadas estimated to be +3.2 °C warmer than at present Left: A dead trunk above current treeline from a foxtail pine that lived about 1000 years ago near Bighorn Plateau in Sequoia National Park.
5 PCs matter: a simple average of MBH proxies does not yield a hockey stick Top: average of MBH proxies. Bottom: result of MBH method.
6 MBH Methods enhance weighting of bristlecones – a proxy rejected by NAS Top – Contribution (deg C) of 10 proxy groups (proxy type x continent e.g. Asian tree rings; South American ice cores) to the MBH reconstruction, with bristlecones/foxtails in red. The bristlecone contribution closely matches the final MBH reconstruction. Bottom – Same series in standard deviation units.
7 New research in late 2005 showed that a bewildering variety of results can be obtained from MBH proxies. Source: Bürger and Cubasch SI Figure 1
8 Moving On?: Precisely the same PC series were used late last year in Rutherford et al 2005 Although 415 individual proxy series were used, data reduction by using leading PCs of tree-ring networks results in a smaller set of 112 indicators in the multiproxy–PC network available back to 1820 (Fig. 1a), with a decreasing number of indicators available progressively further back in time. Twenty-two of the indicators (representing 95 individual proxy series) extend back to at least A.D. 1400.
9 MBH Results Failed Verification r 2 Test Source: Wahl and Ammann 2006
10 Replication Problems Persist MBH source code provided to Committee does not work with any data sets presently archived and is inoperable. code for some important steps, such as MBH99 confidence intervals or the application of Preisendorfers Rule N, was not provided Other authors are even worse: identity of sites in Briffa et al 2001 (also used in Rutherford et al 2005) remain unreported and unavailable
11 You can make a difference … peer review at journals is very limited and is insufficient due diligence for policy reliance; IPCC does not carry out due diligence on articles; to enable and facilitate independent testing, paleoclimate research practices need to achieve dramatically improved standards for archiving data and code; Because much of the work is funded by the U.S. federal government, administrative changes at NSF and DOE would have an immediate impact on paleoclimate due diligence.
12 End of Presentation Sir John Houghton at press conference releasing IPCC Third Assessment Report.
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