Real Climate.Org is chief defender of “consensus” climatology on the Internet. One of its enduring missions has been to defend the dubious, indeed discredited “Hockey Stick” reconstruction of Northern hemisphere temperature history. The Hockey Stick was the basis for the IPCC’s claim in its 2001 report that the 1990s were the warmest decade and 1998 the warmest year of the past millennium.
That Real Climate (RC) should feel special solicitude for the Hockey Stick is no accident, comrade. Two of the five principals at RC — Michael Mann and Raymond Bradley — were among the three researchers (Mann, Bradley, and Malcolm Hughes) who authored the Hockey Stick.
All of the RC principals (Gavin Schmidt, Caspar Ammann, Rasmus Benestad, Mann, and Bradley) are frequent senders and recipients of the thousands of emails and other documents, now posted on many Web sites, that were hacked or leaked last week from the University of East Anglia’s Climate Research Unit (CRU).
The Wall Street Journal today published a selection of the leaked emails and an editorial concluding that the emails “give every appearance of testifying to concerted and coordinated efforts by leading climatologists to fit the data to their conclusions while attempting to silence and discredit their critics.”
Even eco-radical George Monbiot says he is “dismayed and deeply shaken” by the emails, because, “There appears to be evidence here of attempts to prevent scientific data from being released, and even to destroy material that was subject to a freedom of information request.”
So far, the only email on which RC has seen fit to comment is one from CRU director Phil Jones dated Nov. 16, 1999, 13:31. It’s gotten a lot of buzz on the Internet, because it appears to advocate the use of a “trick” to “hide” a “decline” in global temperatures.
In a post titled “The CRU Hack” (November 20), RC writes:
No doubt, instances of cherry-picked and poorly-worded “gotcha” phrases will be pulled out of context. One example is worth mentioning quickly. Phil Jones in discussing the presentation of temperature reconstructions stated that “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’s to hide the decline.” 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”–see 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 recommend 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.
So a “trick” is just scientific shorthand for a “good way to deal with a problem,” not something “secret.” But RC ducks the real issue. Is the “trick” Phil Jones learned from Hockey Stick author Michael Mann a form of trickery? Does it create a false impression, as an illusionist does on stage, right out in the open, in front of an audience?
The trick, according to RC, is to splice onto the end of a temperature reconstruction, built on proxy data going back several centuries, the data from instrumental records starting in 1960 and 1981.
Now this is quite a trick, because it involves comparing apples (proxy data) to oranges (instrumental data) and pretending that the composite forms a continuous record.
As the Center for the Study of Carbon Dioxide and Climate Change observed years ago, researchers attempting to construct long-term (centuries to millennia) temperature records should “finish the dance” with the (proxy) data they started with.
Grafting instrumental data onto proxy data to produce a seemingly continuous record is trickery, because instrumental data, unlike proxy data, are massively influenced by land-use changes and site-specific quality control issues.
Urban heat islands and irrigated agriculture can inject false warming biases into instrumental data that are absent from proxy data taken from remote forests or sediment cores at the bottom of lakes, for example. Improper placement of temperature sensing equipment near local heat sources (e.g. air conditioning vents, asphalt parking lots, waste water treatment plants) also generates significant false warming signals, as retired meteorologist Anthony Watts documents in gory detail.
So RC’s “nothing to see here” argument based on the alleged insider meaning of “trick” raises rather than allays suspicion that CRU is attempting to fit data to a predetermined conclusion.
Note also that RC says nothing about Phil Jones’s advice to backdate correspondence (Sept. 12, 2007, 11:30 a.m.), to delete emails related to the 2007 IPCC report (May 29, 2008, 11:04), and to evade FOIA requests, if necessary by deleting files (Feb. 2, 2005, 9:41 a.m.). RC also says nothing about Mann’s call to delegitimize the Journal of Climate for publishing papers critical of his work (March 11, 2003, 8:14).
The Wall Street Journal editorial’s concluding comment is spot on: “In the department of inconvenient truths, this one surely deserves a closer look by the media, the U.S. Congress and other investigative bodies.”