The Infamous 'Hockey Stick': Tree Scientists Determine Mann's Temperature Graph A Result of Biased Data
A new peer reviewed study determines that research efforts based on tree rings are likely to be wrong due to 'big tree selection bias' - Mann's infamous 'hockey stick' highly likely to be corrupted by this bias
Read here. The majority of scientists have come to believe that Michael Mann's study that produced the infamous 'hockey stick' graph was flawed in a number of ways. A major problem with Mann's research was that it did not match the multiple empirical studies and anecdotal evidence that confirmed the extreme warmth of the Medieval Warming and the cold of the Little Ice Age.
Newly published research by Brienen et al. indicates that Mann's work with tree rings, and others, is likely to be wrong due to a 'big tree selection bias.'
"A paper published this week finds that many tree-ring proxy studies are highly biased and calls for "great caution in the interpretation of historical growth trends from tree-ring analyses." The authors find that "big tree selection bias" resulted in a fictitious "doubling in growth rates over recent decades." Consequently, tree-ring analyses claiming to link growth rates to historical temperatures would show a fictitious large 'hockey stick' increase in temperature over recent decades..."The big-tree selection bias is caused by sampling only the biggest trees in a population. As a result, slow-growing small trees are underrepresented in recent times as they did not reach the minimum sample diameter." [Roel J. W. Brienen, Emanuel Gloor, Pieter A. Zuidema 2012: Global BioGeochemical Cycles]
Conclusion: Michael Mann's infamous 'hockey stick' portrayal of historical temperatures has already proven to be damaged from bizarre mathematical and statistical techniques used, and now the tree ring data utilized in his study is likely to be significantly biased also.
Previous postings about the bizarre science behind the 'hockey stick.'