'ClimateGate': Case closed?

Prof Edward Acton, UEA vice chancellor, and detective chief superintendent Julian Gregory of Norfolk Constabulary

Will we ever know who hacked the "ClimateGate" files, and why?

Probably not, judging by the insights gained by the Norfolk police force during their two-and-a-half-year investigation, which they've just closed.

It's a decision that's caused a fair amount of frustration.

Prof Edward Acton, vice chancellor of the University of East Anglia from where the material was filched in 2009, described himself as "disappointed"; while the Union of Concerned Scientists, which argues for tougher international action on climate change, said it was "a big shame" that whoever stole the material "had got away with it".

At a news briefing in Norfolk Constabulary headquarters in Wymondham, one sensed that the officers running the investigation shared the frustration.

Here was a crime with international ramifications that happened on their patch - the theft and release of more than 6,000 e-mails and other documents that lit a fire under mainstream climate science, perhaps contributing to the torpor in the UN climate process and raising the level of doubt in public minds.

Yet despite engaging help from the UK's specialist e-crime unit, IT security consultants and police forces in other countries, they've identified not a single suspect.

What they have concluded is that there were several "remote attacks via the internet" on CRU's servers between September and November 2009.

Some, but by no means all, of the material was released in two batches - immediately before the UN climate summits in Copenhagen in 2009 and Durban in 2011.

Various internet rumours have it that the hack was performed or commissioned by countries keen to avoid tight constraints on greenhouse gas emissions - or by oil companies, or bloggers with demonstrable IT expertise.

To those hoping that the investigation would at least hint as to whether any of these rumours were true or false, the officer in charge, detective chief superintendent Julian Gregory, gave nothing.

"From the investigation, I can't offer anything at all on that," he said.

"What I can say is there is a high degree of sophistication. That could have rested with one individual, or with some kind of state or commercially sponsored activity; but there was nothing from the investigation that indicates where responsibility lay."

At the outset, three avenues of inquiry presented themselves:

• to follow the electronic trail left by the process of releasing material on the web

• to follow electronic clues left in the hacked servers at UEA's Climatic Research Unit (CRU)

• to look for evidence of an inside job.

Having decided early on that the first path wasn't practical - "it's not possible to investigate the internet," as Mr Gregory put it, given the elusive nature of proxy servers - police drew a similar blank with the second.

"We've described the hack as 'sophisticated' - that's the view of our experts," he told reporters.

"They identified that as well as achieving the breach, [the perpetrators] concealed their tracks, they laid false trails... the person or persons were highly competent in what they were doing."

Only on the third issue has there been resolution.

The Climatic Research Unit (CRU) compiles one of the most widely used temperature records

After speaking "to everyone" at CRU and looking for signs of entry around the unit, Mr Gregory declared: "There's no evidence to say anybody connected with UEA was involved."

Even here there was a caveat.

"Because we haven't found who is responsible, we can't say categorically that no-one from UEA was involved; but there's no evidence that anyone was, and the nature and sophistication of the attack also suggests no-one from UEA was involved."

On other issues, he wouldn't be drawn.

They'd worked with police in other countries; some had been helpful, others not, but he wasn't prepared to name names.

Nor was he prepared to list people who'd been questioned.

Could the police have done more? Some argue they should have, with ThinkProgress, for example, dubbing the investigation "botched".

The raw figure of £84,000 spent on the investigation over two and a half years doesn't sound very much, although Mr Gregory pointed out this covers only specific spending on the case by Norfolk Constabulary - not routine items such as staff wages, nor what might have been disbursed by specialist national agencies who are not in the habit of divulging information about their activities.

But police forces are supposed to devote "proportionate" amounts of effort to the various cases they're investigating; and given that nobody died or was physically beaten up in the commission of this particular crime, many might argue that no more money should have been spent.

After all, it isn't the police force's job to tackle the tsunami of doubt that "ClimateGate" spewed into the court of public opinion on climate change.

So where do we go from here?

CRU's importance has always lain in the foundations it puts under the edifice of climate science.

If its record of historical global temperatures is flawed - still more if its scientists have wilfully manipulated that record - the edifice tumbles down.

It would invalidate much of the data going into computer models projecting climate change, in turn nullifying arguments that there's a burning need to do something about it.

As an institution, CRU has survived the episode with its main scientific staff still functioning, but with reforms to its operation in terms of increased openness - changes that many mainstream scientists believe will be beneficial to all in the long run.

More importantly, its temperature record has since been broadly validated and corroborated, not least by the Berkeley Earth project.

The foundations of the edifice, then, are still intact. In that sense, identifying the hacker(s) wouldn't make much difference to the world.

What it would do is shed light on who precisely is willing to go to such lengths to shake the edifice, and why.

Police professionally deal in motives as well as evidence.

And here, Mr Gregory was prepared to venture an educated guess.

"You would say that the nature of the data that was taken - quite selectively - and published on the internet appears to have been done with the intention to undermine the science that supports anthropogenic climate change.

"That, combined with the fact that the data was published immediately before global [UN climate] conferences, would lead to the conclusion that it was done with the intention of trying to influence the outcome of those conferences."

Whether "ClimateGate" was as significant in slowing progress in the UN talks as other factors is unclear.

You can argue plausibly that it was less important than a succession of cold winters in North America and western Europe, the burgeoning muscles of emerging economies, paralysis in the US political system, the growing desire of Arctic states to secure mineral resources in the region, and petro-states' domination of the G77/China bloc.

But in the folklore of the sceptical blogosphere, it's achieved cult status; no doubt about that.

Will the perpetrator eventually want to claim credit? Will that, in the end, reveal what the Norfolk police could not?