Overview
The timing was the first thing anyone noticed. On 17 November 2009, with the Copenhagen climate conference three weeks away, a file appeared containing roughly a thousand emails and several thousand documents copied from a backup mail server at the Climatic Research Unit of the University of East Anglia. By 19 November it was everywhere. The unit was one of the small number of institutions maintaining a global surface temperature record, which made its internal correspondence unusually consequential reading.
Within days the material had a name, and the name did a lot of the arguing: Climategate. What followed was less a debate about climate science than a debate about two sentences.
The Two Phrases
The first was from a 1999 message by the unit's director, Phil Jones, referring to "Mike's Nature trick" and to hiding "the decline." Read cold, in a stolen email, by people who had no reason to extend goodwill, it sounded like a confession — a trick to hide a decline in temperatures.
The technical referent is narrower. The "decline" is the tree-ring divergence problem: from about 1960 onward, certain tree-ring width series stop tracking measured temperatures, drifting downward while thermometers rise. The divergence was not a secret. It had been described in the published literature years before the emails were taken, and it remains an open question in dendroclimatology. The "trick" was a method of splicing instrumental temperature data onto the proxy reconstruction for the period where the proxies were known to fail — a presentational choice that was disclosed in the relevant papers, and which critics argued was still the wrong choice to make in a figure aimed at a general audience.
That gap — between what the phrases meant to the people who wrote them and what they meant to everyone who read them ten years later — is the whole event in miniature.
Eight Inquiries
The response was unusual in its volume. Over roughly twenty months, eight separate bodies examined the affair.
The House of Commons Science and Technology Committee reported on 31 March 2010 and found that the scientific reputation of Jones and the unit remained intact. A science assessment panel chaired by Lord Oxburgh reported on 14 April 2010 and found no evidence of deliberate scientific malpractice. Two Pennsylvania State University panels examined Michael Mann, reporting in February and June 2010, and concluded he had neither suppressed nor falsified data. The Independent Climate Change Email Review under Sir Muir Russell reported on 7 July 2010 and said the rigour and honesty of the scientists were not in doubt. The U.S. Environmental Protection Agency reported on 29 July 2010 that petitions built on the emails rested on selectively edited, out-of-context material. The Inspector General of the U.S. Department of Commerce reported on 18 February 2011 finding no evidence that NOAA had inappropriately manipulated data. The National Science Foundation's Office of Inspector General closed its investigation on 15 August 2011 finding no evidence of research misconduct.
The inquiries were not uniformly kind. Several were pointed about the unit's culture of resistance to disclosure, its handling of freedom-of-information requests, and a defensiveness that had made an ordinary scientific dispute look like something worth hiding. A 2011 parliamentary report concluded it was time to move on.
The Part Nobody Solved
One question outlasted all eight investigations: who took the files. The material was posted anonymously, routed through a server traced to a Saudi Arabian IP address, and the intruder was never identified. Norfolk Constabulary closed its investigation on 18 July 2012, concluding there was no realistic prospect of identifying the offender and finding no evidence that anyone working at or associated with the university had been involved.
A second, smaller release followed in November 2011, drawn from the same original haul.
Why the Findings Did Not Settle It
For those persuaded the emails showed misconduct, the inquiries were not a resolution but part of the pattern. Several were run by the university that employed the scientists or the university that employed Mann; the Oxburgh panel was small, quick, and did not take evidence in public; the Commons committee heard from a limited range of witnesses under time pressure before a general election. That institutions investigating themselves would clear themselves was, in this reading, exactly what one would predict.
The counter-argument is that the inquiries were not a single body but eight, spanning two countries, four institutions, a parliamentary committee, two federal inspectors general and a regulatory agency, and that they examined different questions with different powers. But the structure of the objection means no number of inquiries can close it — each additional clearance is available as further evidence of the thing being covered up.
Afterwards
The temperature record itself did not move. Independent reconstructions built by other groups from other data, including an effort explicitly launched by researchers sympathetic to the critics, reproduced the same warming trend. What changed was procedural: the unit's data and code were opened up, and climate institutions became markedly more careful about disclosure.
What also changed was the vocabulary. "Climategate" is still deployed as a settled reference, usually by people who have not read the emails, and the two phrases still circulate detached from the paragraphs around them. The event is now most useful as a case study in what happens when private working correspondence — written in shorthand, between colleagues, about a known technical problem — is read in public by an audience with no access to the shorthand.