Thursday, November 26, 2009

The Hadley CRU Scandal

Here's a good article written by Declan McCullagh with CBS News explaining the Hadley CRU scandal (HT Megan McArdle). The entire article is well worth reading, I'll however focus on the following passages:

As the leaked messages, and especially the HARRY_READ_ME.txt file, found their way around technical circles, two things happened: first, programmers unaffiliated with East Anglia started taking a close look at the quality of the CRU's code, and second, they began to feel sympathetic for anyone who had to spend three years (including working weekends) trying to make sense of code that appeared to be undocumented and buggy, while representing the core of CRU's climate model.

One programmer highlighted the error of relying on computer code that, if it generates an error message, continues as if nothing untoward ever occurred. Another debugged the code by pointing out why the output of a calculation that should always generate a positive number was incorrectly generating a negative one. A third concluded: "I feel for this guy. He's obviously spent years trying to get data from undocumented and completely messy sources."

The leaked documents (see our previous coverage) come from the Climatic Research Unit of the University of East Anglia in eastern England. In global warming circles, the CRU wields outsize influence: it claims the world's largest temperature data set, and its work and mathematical models were incorporated into the United Nations Intergovernmental Panel on Climate Change's 2007 report. That report, in turn, is what the Environmental Protection Agency acknowledged it "relies on most heavily" when concluding that carbon dioxide emissions endanger public health and should be regulated.

Last week's leaked e-mails range from innocuous to embarrassing and, critics believe, scandalous. They show that some of the field's most prominent scientists were so wedded to theories of man-made global warming that they ridiculed dissenters who asked for copies of their data ("have to respond to more crap criticisms from the idiots"), cheered the deaths of skeptical journalists, and plotted how to keep researchers who reached different conclusions from publishing in peer-reviewed journals. ...

Programmer-written comments inserted into CRU's Fortran code have drawn fire as well. The file briffa_sep98_d.pro says: "Apply a VERY ARTIFICAL correction for decline!!" and "APPLY ARTIFICIAL CORRECTION." Another, quantify_tsdcal.pro, says: "Low pass filtering at century and longer time scales never gets rid of the trend - so eventually I start to scale down the 120-yr low pass time series to mimic the effect of removing/adding longer time scales!" ...

The irony of this situation is that most of us expect science to be conducted in the open, without unpublished secret data, hidden agendas, and computer programs of dubious reliability. East Anglia's Climatic Research Unit might have avoided this snafu by publicly disclosing as much as possible at every step of the way.

Indeed, the methods, practices, behaviors and attitudes of the "scientists" described in the hacked documents are not scientific by any standard. What is depicted in them characterizes, to say the least, grave unethical academic conduct and politicking of the worst possible kind. Fortunately to me, I've never witnessed among fellow economists an anti-scientific predisposition of this magnitude. Maybe economists should be proud of their profession after all.

Anyway, Happy Thanksgiving to you all!

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