Here it is. Rebuttal follows:
What does "hide the decline" refer to?
Phil Jones' email is often cited as evidence of an attempt to "hide the decline in global temperatures". This is incorrect. The decline actually refers to a decline in tree-ring density at certain high-latitude locations since 1960. However, Muller doesn't make this error - he clearly understands that global temperatures have been rising in recent decades as indicated by the instrumental record.
Tree-ring growth has been found to match well with temperature, and hence tree-ring width and density is used to plot temperature going back hundreds of years. However, tree-rings in some high-latitude locations diverge from modern instrumental temperature records after 1960. This is known as the "divergence problem". Consequently, tree-ring data in these high-latitude locations are not considered reliable after 1960 and should not be used to represent temperature in recent decades.
The expected deception above:
1). MOST if not all, the tree ring data used by Briffa and Jones was from "certain high-latitude locations". The impression created above that those records were of minor importance is therefore the reverse of the truth. They were central to the entire temperature reconstruction.
2). If the tree ring data diverge totally from the thermometer data over one time period, how do we know that they are a valid measure of temperature at all? We do not. They could well have diverged in earlier periods too. Yet it is precisely tree rings that Jones & Briffa rely on to portray earlier temperatures.
The "decline" did desperately need to be hidden -- as it shows that the entire temperature record for pre-thermometer days is based on an invalid measuring instrument and may therefore in fact be no record of pre-thermometer temperatures at all. And given the clash between Mann's hockeystick and known history, that doubt firms into a certainty.