Climate science and its discontents

A place in the sun
The scientists in “climategate” did not fudge the data, a report finds
Apr 14th 2010 | From The Economist print edition

RON OXBURGH, breezily pushing his bicycle through a clot of journalists outside the press briefing he had just given, is a busy man happy to hurry. Critics of his investigation into the scientific probity of the Climatic Research Unit (CRU) at the University of East Anglia will hold that haste against him. In his time Lord Oxburgh has been head of the earth sciences department at Cambridge, chief scientific adviser to Britain's defence ministry and, briefly, chairman of Shell. In March he was asked to lead an inquiry into the CRU's key scientific findings, a matter of much debate ever since hacked e-mails from the unit were made public less than five months ago. That he has reported so soon, and in a way that supports the CRU researchers, will be seen by many critics as de facto evidence of a whitewash.

Lord Oxburgh and his colleagues were not concerned with whether CRU's scientific findings, which are based on records of temperature change from instruments and natural proxies, were correct. They were looking to see if the analysis had been biased and manipulated.

The inquiry panel looked at 11 CRU publications from the past 20 years, spent days talking to the researchers and looking at other documentation, and concluded that if there was any malpractice at CRU they would have detected it. They found no such thing. Instead they found “dedicated if slightly disorganised researchers ill-prepared for public attention”.

The panel did express considerable surprise at the fact that the unit did not collaborate closely with professional statisticians. This is despite the fact that their work was “basically all statistics”, as one member of the panel, David Hand, of Imperial College, London, put it. The report found that the CRU scientists would, had they been more comfortable with statistics, have done some things differently. But the panel doubted that using better methods would have materially changed their results.

Bloggers and others, mostly outside academia, who criticise CRU's work and other climate science tend to lay much stress on statistical shortcomings. Dr Hand, who has a particular interest in scientific and financial fraud, has read a lot of this work. Dr Hand admires the meticulous work of Steve Mcintyre, a mining consultant and blogger, who unearthed statistical problems in another climate analysis. This was a 1998 paper, not produced by CRU, that is now known as “the hockey stick”. Those problems served to enhance the prominence of recent warming in a thousand-year reconstruction of the northern hemisphere's temperature, and have become a cause celebre among sceptics.

When the report refers to the possibility of “inappropriate statistical tools producing misleading results”, it is the hockey stick that it has in mind. But Dr Hand said he had seen no evidence of anything that worrying in the CRU work. His concerns centred mostly on questions about the selection of data sets and the need for studies that showed how sensitive the results were to different selections of data. These are, in effect, what some critics are offering (though with what the report calls “a rather selective and uncharitable approach”. This antagonism irritates Dr Hand, since he thinks proper statistical scrutiny would have improved the work with little fuss. “What I want to do”, he says, “is bang their heads together and say sit down together and work out what's going on.”

The panel expressed concern that, although the CRU scientists were careful with caveats, people who subsequently made use of their results, including the Intergovernmental Panel on Climate Change, sometimes oversimplified the issues, underplaying possible errors. It also noted that the CRU should have archived data and algorithms better, but that this was a conclusion more easily drawn in hindsight. Having been in both academia and industry, Lord Oxburgh said he has no doubt that in industry, where companies, not researchers, own the data, the record-keeping would have been looked after better, but that the team would have done much less good research. And looking back on his own academic work he showed a certain solidarity with his own subject's sloppiness. He says he is “very grateful that the isotopic composition of helium has not become a key matter of public interest.”


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