A third and final independent review of the hacked emails of scientists at the UK's premier Climatic Research Unit (CRU) declared on Wednesday that it "did not find any evidence" of improper behavior that would undermine the consensus on human-caused global warming.
"On the specific allegations made against the behavior of CRU scientists, we find that their rigor and honesty as scientists are not in doubt," the 160-page Independent Climate Change Emails Review said.
However, the British panel of experts said there were signs of "unhelpfulness" in handling "legitimate" requests for data.
"There has been a consistent pattern of failing to display the proper degree of openness," the review stated.
Last December, more than 1,000 private emails by over 160 authors, some dating back 13 years, were leaked or stolen from a computer server at the University of East Anglia's CRU and posted online. The controversy, called Climategate, stirred a global uproar.
Global warming skeptics seized on the scandal to cast doubt on the climate consensus and inflame public debate weeks before the UN Copenhagen summit.
They said the correspondence revealed attempts by scientists to suppress and doctor raw temperature data and computer code in an attempt to overstate their case for a warming world.
This week's review knocked down that claim, however.
"Any independent researcher may freely obtain the primary [weather] station data," it said. "It is impossible for a third party to withhold access to the data."
Scientists involved said the new study, funded by the University of East Anglia and led by Sir Muir Russell, a former senior servant and vice chancellor of Glasgow University, should put to rest many of the skeptics' allegations.
Phil Jones, head of CRU, who was linked to nearly 200 of the primary emails, said he was "extremely relieved" with the study.
"We have maintained all along that our science is honest and sound and this has been vindicated now by three different independent external bodies," Jones said.
Third Time's a Charm?
The report marks the third and final inquiry into the cache of hacked material.
The first was released in March by the House of Commons Science and Technology Committee. The second, completed in April, was conducted by a group of independent researchers recommended by the Royal Society, a national science academy in Britain, and led by Ron Oxburgh, a former geologist and Shell chair.
All three audits have exonerated the British and American researchers involved of any willful impropriety. But none carry more weight than the so-called Russell Review.
Russell and his four-member team, who boast "100 years' collective expertise of scientific research," were asked by the University of East Anglia on December 3, to examine the conduct of CRU researchers and inspect allegations of data manipulation.
CRU uses temperature data recorded at 4,000 of the world's 7,000 land-based weather stations worldwide, the study said.
One of the main complaints thrown up by skeptics is that CRU withheld that data and the computer code needed to reproduce the numbers.
But the review said the data is "freely" available to independent researchers. Further, "the computer code required to read and analyze the instrumental temperature data is straightforward to write based upon the published literature."
"We conclude that the argument that CRU had something to hide does not stand up," Russell told reporters on Wednesday.
Not unlike the two other inquiries, the quality of climate science itself was not under scrutiny.
Not Guilty, But Not Scot-Free
The CRU, established in 1972, has been instrumental in producing a temperature data record that has been cited prominently in the influential reports of the UN Intergovernmental Panel on Climate Change (IPCC).
In its 2007 Fourth Assessment Report, the IPCC declared for the first time that global warming is "unequivocal" and human activities are "very likely" the driver.
"We did not find any evidence of behavior that might undermine the conclusions of the IPCC assessments," the Russell Review said.
Still, the CRU scientists did not get off scot-free.
Among several critiques, the study said the "spirit of openness enshrined" in the UK's Freedom of Information Act (FOIA) and the Environmental Information Regulations (EIR) "was not embraced" by CRU scientists.
"The Review found an ethos of minimal compliance (and at times non-compliance) by the CRU with both the letter and the spirit of the FoIA and EIR," it said.
"We recognize that there was deep suspicion within CRU, as to the motives of those making detailed requests. Nonetheless, the requirements of the legislation for release of information are clear and early action would likely have prevented much subsequent grief."
Further, although the report said temperature data is available, it accused CRU of wrongfully withholding the names of the weather stations from which it plucked the figures. "It should not have withheld station identifiers ... so that their work could be precisely replicated," it said.
"We find that CRU's responses to reasonable requests for information were unhelpful and defensive."
The report suggested that the lack of transparency at CRU has harmed the credibility of UK climate science. It recommended three steps to mend the institute's tarnished image:
- Risk management processes should be directed to ensuring top management engagement in areas which have the potential to impact the reputation of the university.
- Compliance with FoIA/EIR is the responsibility of UEA faculty leadership and ultimately the Vice-Chancellor. Where there is an organisation and documented system in place to handle information requests, this needs to be owned, supported and reinforced by University leadership.
- CRU should make available sufficient information, concurrent with any publications, to enable others to replicate their results.
The work was welcomed by the climate scientists whose emails have been under investigation.
Writing on the RealClimate blog, co-founders Gavin Schmidt, a climatologist at NASA, and Michael Mann, a meteorology professor at Penn State University, called the report "surprisingly thorough."
"The main issue is that they conclude that the rigor and honesty of the CRU scientists is not in doubt ... and we are very pleased to have this proclaimed so vigorously," they wrote in a joint post. "Secondly, they conclude that none of the emails cast doubt on the integrity and conclusions of the IPCC, again, something we have been saying since the beginning."
Last week, Mann was cleared by a Penn State investigative committee of any ethical misconduct in connection with Climategate.
In an email statement on the Russell Review he stated: "It is my hope that we can now put this bogus, manufactured scandal behind us, and move on to a more constructive conversation about climate change."
Stephen McIntyre, who runs Climate Audit, a website critical of climate science, said "the report is heavily weighted towards CRU apologia." He suggested that the review ignores violations of IPCC rules by scientists that he claims undermine current climate science. That lax due diligence will soon come to light, however, he said.
"It seems clear to me that Muir Russell contains many gaffes and errors, which are going to get placed into the sunshine over the next few days, as critics get a chance to work through the report," McIntyre wrote. "It's too bad that Muir Russell decided that it was a good idea not to interview critics during the preparation of the report."