Mining For Hockeysticks
15 hours ago Willis Eschenbach 104 Comments
Guest Post by Willis Eschenbach (@weschenbach on Ex-Twitter)
The iconic “hockeystick” simply refuses to die. It was first created by Mann, Bradley and Hughes in their 1998 paper Global-scale temperature patterns and climate forcing over the past six centuries (hereinafter “MBH98”).
Figure 1. Original hockeystick graph
MBH98 claimed to show that after a long period with very little change, suddenly the world started warming, and warming fast.
Back a couple of decades ago, Steve McIntyre over at Climate Audit did yeoman work in discovering a host of errors in MBH98. And somewere in that time, someone, likely Steve but perhaps not, noted that the curious (and mathematically incorrect) procedure used in MBH98 could actively mine hockeysticks out of red noise.
[UPDATE]: The unstoppable Rud Istvan noted in the comments that McIntyre and McKitrick published Hockey sticks, principal components, and spurious significance in 2005..
I also find Mann, Bradley and Hughes reply to that study, Reply to McIntyre and McKitrick: Proxy-based temperature reconstructions are robust, which says in part:
https://wattsupwiththat.com/2024/06/29/mining-for-hockeysticks/
