By Fred Pearce, www.guardian.co.uk, Monday 1 February 2010 18.04 GMT
…The Alaskan governor Sarah Palin, in the Washington Post on 9 December, attacked the emailers as a "highly politicised scientific circle" who "manipulated data to 'hide the decline' in global temperatures". She was joined by the Republican senator James Inhofe of Oklahoma – who has for years used his chairmanship of the Environment and Public Works Committee to campaign against climate scientists and to dismiss anthropogenic global warming as "the greatest hoax ever perpetrated on the American people". During the Copenhagen climate conference, which he attended on a Senate delegation, he referred to the Jones's "hide the decline" quote and said: "Of course, he means hide the decline in temperatures."
This is nonsense. Given the year the email was written, 1999, it cannot be anything else. At that time there was no suggestion of a decline in global temperatures. The previous year was the warmest on record, coming on top of a run of record warm years in the warmest decade of the century. It is only in the decade since that the rise in temperatures has slackened, due to natural cycles of variability.
The full email from Jones says: "I've just completed Mike's Nature trick of adding in the real temps to each series for the last 20 years (ie from 1981 onwards) and from 1961 for Keith [Briffa]'s, to hide the decline." The decline being referred to was an apparent decline in temperatures shown in analysis of tree rings. Tree rings have historically correlated well with changes in temperature, but that relationship has broken down in the past half century. The reasons are still debated among scientists.
The "trick" was a graphic device used by Mann in a 1998 paper in Nature to merge tree ring data from earlier times with thermometer data for recent decades. He explained it in the paper. Jones was repeating it in another paper. "This is a trick only in the sense of being a good way to deal with a vexing problem," Mann told the Guardian. …
Several other soundbites were subject to perverse or dishonest interpretations by commentators. Patrick Michaels, the climatologist and heavyweight polemicist for the rightwing Cato Institute published a long op-ed piece in the DC Examiner, slamming Mann for an email quote about keeping sceptics' papers out of the IPCC report "even if we have to redefine what the peer-reviewed literature is". Michaels is an old foe of Mann's, but this genuinely damaging statement was actually made by Jones.
In another case George Will, celebrated in some circles as an intellectual, told ABC's This Week programme that Mann had said in an email that he wished to "delete, get rid of, the medieval warming period". No such words appear anywhere in the emails. What Mann actually said was that "it would be nice to try to 'contain' the putative 'MWP'". Some bloggers suggested this amounted to extinguishing it from the data record. But an intellectual like Will should have known that, in this context, "contain" means to understand its dimensions – how warm it was and how long it was. Mann explained as much to anyone who asked. Verdict: not guilty. …
Thursday, February 4, 2010
Claims based on email soundbites are demonstrably false – there is manifestly no evidence of clandestine data manipulation