Muller Misinformation #2: 'leaked' tree-ring data
We recently examined several lectures where Professor Richard Muller confused "Mike's trick" with "hide the decline". In these lectures, Muller provided further misinformation when he claimed the "decline" data was withheld from the public until it was "leaked" at Climategate. Muller claims:
“In their paper, if you dig into it, they say they did some things with the data from 1961 onwards - they removed it and replaced it with temperature data. So some of the people who read this paper asked to see the data, they refused to send it to them, the original raw data. They used the FOI act. The FOI act officer on the advice of the scientist would not release the data. Then the data came out. They weren't hacked like a lot of people say. Most people who know this business believe they were leaked by one of the members of the team who was really upset with them.”
In Muller Misinformation #1, we see that the "decline" refers to a decline in tree-ring density at certain high latitudes. The tree-ring density measurements come from Briffa 2000. The original tree-ring density data is shown below with the green line represents tree-ring density and the thick black line showing the instrumental temperature record. Note the divergence in the late 20th century.
Figure 1: An indication of growing season temperature changes across the whole of the northern boreal forest. The LFD curve indicates low-frequency density changes. Note the recent disparity in density and measured temperatures.
Muller claims that Briffa's data was withheld from the public until it was "leaked" in late 2009 at the time of "Climategate". This is untrue. The Briffa 2000 data was already freely available via the Climatic Research Unit (CRU) website. This had been online since late 2008, as documented by Steve McIntyre.
What about the "original raw data" that Muller claims was refused to the public. The original raw data for the tree-ring density comes from the "Schweingruber" network, consisting of 387 chronologies from across the northern hemisphere. This data was also freely available online via the CRU website. This link was given to Steve McIntyre in October 2008 in response to a Freedom of Information request to CRU, as seen in this lengthy document of FOI requests made to CRU (FOI 08-50 on page 169).
Briffa's data was not leaked during "Climategate". Professor Muller's assertion that the post-1960 "decline" data was not made available is incorrect.