Category Archives: Post-1980 Proxies

A Cook's Tour

Cook et al. [2004] is a “reconstruction of past drought across North America from a network of climatically sensitive tree-ring data”. It uses 835 sites in North American regions overlapping Mann’s PC network. I thought that it would be interesting to compare the two networks. Of course nothing is straightforward when you’re dealing with the […]

Bring the Proxies Up to Date!!

I will make here a very simple suggestion: if IPCC or others want to use “multiproxy” reconstructions of world temperature for policy purposes, stop using data ending in 1980 and bring the proxies up-to-date. I would appreciate comments on this note as I think that I will pursue the matter with policymakers.

Post-1980 Proxies #4: Wilmking et al. [2004]

Wilmking et al. carried out a comprehensive sampling of 1558 white spruce trees at 13 treeline sites in the Brooks Range and Alaska Range. The date of the sampling is not stated but seems to be between 2000 and 2003 and includes the warm 1990s. These findings cover the same species as were primarily used […]

Post-1980 Proxies #3: Chesapeake Bay Mg/Ca

The Chesapeake Bay Mg/Ca proxy goes to late 1995 and is used in both Moberg et al [2005] and Mann and Jones [2003] for the proxy reconstructions up to 1980. Figure 1 below shows that its post-1980 behavior does not show an exceptional response to supposedly unprecedented temperature. Figure 1. Chesapeake Bay Spring SST. Re-plotted […]

Post-1980 Proxies #2: Alaskan Tree Rings

D’Arrigo et al. [GRL 2004] reports on tree rings taken from the Seward Peninsula in northwestern Alaska from white spruce from 14 sites near elevational treeline in summer 2002. We show here their figures, demonstrating that the "proxy" show no evidence of the warm 1990s and hot 1998, raising questions about the ability of this […]

Post-1980 Proxies #1: Twisted Tree Heartrot Hill

I get a lot of questions about post-1980 proxies and I find it a very interesting question. One would expect that 1998 – the "warmest" year of the millennium – and the 1990s – the "warmest decade" of the millennium would leave a loud signal in a valid proxy. I’m going to start discussing some […]

The Updated Gaspé Series

We have focused considerable attention on the role of the Gaspé series in MBH98. While we alluded previously in MM05 (E&E) to information in our possession that the updated (1991) version of the series differed from the 1982 version and to our frustration that the updated version remains unarchived (see Jacoby #1) , we are […]