by S. McIntyre, Nov 2, 2021 in ClimateAudit
One of the central claims of The Trick, if not the most central claim, was that “hiding the decline” was nothing more than an inopportune phrase about a single diagram.
The “trick to hide the decline” was an inopportune, if revealing, phrase, but rather than the issue being limited to a single diagram, the inconsistency between the Decline (in observed tree ring widths and densities) and the Hockey Stick temperature reconstructions (primarily based on tree ring widths) was, together with the looting of the Baghdad Museum, the issue that inspired my original examination of Michael Mann’s Hockey Stick and was the driving theme of Climate Audit from its origin up to Climategate. There are dozens, even hundreds, of Climate Audit articles that, in one way or another, relate back to the conundrum arising from the inconsistency of the underlying proxies and the superficial consistency of the reconstructions.
In this and a couple of follow-on articles, I’ll illustrate the centrality of The Decline vs The Stick in the controversies in the years prior to Climategate. For the benefit of people that may be new to these disputes, I re-iterate that I never interpreted the late 20th century decline in ring widths as evidence of a decline in temperatures, but as a seriously problematic inconsistency for “reconstructions” relying in large part on tree rings.
When I say that the Decline inspired my original examination of Michael Mann’s Stick, it is literally true.
I had become mildly interested in climate issues in late 2002 when the Canadian government was promoting the Kyoto treaty, including in its promotion the assertion that 1998 was the “warmest year” in 1000 years. This was based on the 2001 IPCC Assessment Report, which included multiple versions of the Hockey Stick graph, one of which was the following: