An excerpt from one November 1999 email authored by the head of the CRU, Phil Jones, reads, "I've just completed Mike's Nature [the science journal] trick of adding in the real temps to each series for the last 20 years (ie, from 1981 onwards) and from 1961 for Keith's to hide the decline."
 The RealClimate website, in their response to the CRU hack, characterizes the excerpt as follows:
The paper in question is the Mann, Bradley and Hughes (1998) Nature paper on the original multiproxy temperature reconstruction, and the 'trick' is just to plot the instrumental records along with reconstruction so that the context of the recent warming is clear
. Scientists often use the term "trick" to refer to a "a good way to deal with a problem", rather than something that is "secret", and so there is nothing problematic in this at all. As for the 'decline', it is well known that Keith Briffa's maximum latewood tree ring density proxy diverges from the temperature records after 1960 (this is more commonly known as the "divergence problem"ľsee e.g. the recent discussion in this paper) and has been discussed in the literature since Briffa et al in Nature in 1998 (Nature, 391, 678-682). Those authors have always recommended not using the post-1960 part of their reconstruction, and so while 'hiding' is probably a poor choice of words (since it is 'hidden' in plain sight), not using the data in the plot is completely appropriate, as is further research to understand why this happens.
Several websites of global-warming sceptics quoted a line written by Trenberth, a climatologist at the National Center for Atmospheric Research, discussing gaps in understanding of recent temperature variations: "The fact is that we can't account for the lack of warming at the moment and it is a travesty that we can't," Trenberth wrote. However, Trenberth told the Associated Press that the phrase was actually used in an article he authored calling for improvement in measuring global warming to describe unusual data, such as rising sea surface temperatures. The word travesty refers to what Trenberth sees as an inadequate observing system that, were it more adequate, would be able to track the warming he believes is there.