Wednesday, July 07, 2010

‘Climategate’ review clears scientists and replicates their results

The long-awaited third review of the co-called 'Climategate' affair chaired by Sir Muir Russell has cleared the Climatic Research Unit (CRU) of the University of East Anglia (UEA) of any wrong-doing.

The scientists at the heart of the matter, particularly Professor Phil Jones, have been cleared of any attempt to mislead or manipulate data or display bias. The report concludes, "we find that their rigour and honesty as scientists are not in doubt."

The review team also tried to replicate the CRU's results using publicly available data which critics had said was not possible. This confirmed the conclusions of the IPCC and CRU that average global temperatures are increasing.

In November 2009, approximately 1000 e-mails from the Climatic Research Unit
(CRU) of the University of East Anglia (UEA) were hacked into by climate sceptics and published on blogs.

CRU is a small research unit which over the last 30 years has played an important role in the development of climate science, in particular in their work on developing global temperature trends.

The leak happened in the run-up to the Copenhagen climate talks last November and were partly responsible for a rise in perceived scepticism of the reality of global warming. The results of those climate talks are widely held to have been disappointing.

It's therefore vitally important that the science behind the IPCC's verdicts on climate change is held up to rigorous scrutiny and perceived to be robust.

But scientists have been their own enemy too often in this respect. So besides urging the to be more open, the Review urges them to learn to communicate and defend themselves better.

The 'blogosphere' has been the principle arena for attacking their work. The
Review team therefore "simply urges all scientists to learn to communicate their work in ways that the public can access and understand."

But also "scientists should be supported to explain their position, and ... a public space can be created where these debates can be conducted on appropriate terms, where what is and is not uncertain can be recognised".

The Russell Report's conclusions

In a nutshell, the report says:

• there's no evidence of behaviour that might undermine the conclusions of the IPCC assessments
• CRU was not in a position to withhold access to land station temperature data or tamper with it
• no evidence of bias in the selection of stations for evidence
• no evidence to support that implication that CRU s work in this area shouldn't be trusted
• there was no subversion of the peer process
• the phenomenon of “divergence” in expressing the uncertainty associated
with reconstruction is not hidden and that the subject is openly and extensively discussed in the literature, including CRU papers
• the way that data derived from tree rings is described and presented in Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) in 2007 is not misleading
• the references in a specific e-mail to a "trick" and to "hide the decline" in respect of a 1999 World Meteorological Organization (WMO) report figure show evidence of intent to paint a misleading picture, we find that, given its subsequent iconic significance (not least the use of a similar figure in the IPCC Third Assessment Report), the figure supplied for the WMO Report was misleading.

However on the negative side:
• CRU should have made available an unambiguous list of the stations used in each of the versions of the Climatic Research Unit Land Temperature Record
• CRU’s responses to reasonable requests for information were unhelpful and defensive
• Ruusell urges CRU to follow "the conventional scientific method of checking and seeking to falsify conclusions or offering alternative hypotheses for peer review and publication".

The question of replication
A chief criticism of CRU was that it did not make available the raw data collected from the weather-monitoring land stations, which it used to produce its report. Nor did it make available the computer code used to crunch these numbers.

To test this, the Review team tried to replicate the process adopted by CRU themselves.

They found three sources of data that are publicly available and would be known to scientists working in the field. They were able, using a competent programmer, to write their own code in just two days to process this data.

They then ran the data through the process and compared it to the results obtained by CRU and to the results published in the IPCC’s 4th report.

What is significant is that all four lines - shown below - more or less tally.
Global warming temperature rise graph by the Russell Review
Global warming temperature rise graph in the IPCC 4th report

In other words, the data is publicly available, easily processed, and produces graphs showing temperature increases that corroborate each other.

They note that it doesn't even matter that some of the land stations are urban and may be influenced by the 'heat island' effect – another criticism of CRU by sceptics like Benny Peizer. The overall trend of temperature change is still upwards, rising with the same degree of statistical variation.

The need for openness

However the Review does say that CRU should have been more open - a view expressed also by the House of Commons science and technology select committee in their report on 31 March. That report concluded that "Professor Jones has in many ways been scapegoated as a result of what really was a frustration on his part that people were asking for information purely to undermine his research."

But the Russell Review says "Without such openness, the credibility of their
work will suffer because it will always be at risk of allegations of concealment
and hence mal-practice."

Frustrating as it is, it is part of his job to deal with such enquiries, or at least that of the UEA who should have responded to the freedom of information requests, not CRU, as the Select Committee observed.

Lord Oxburgh's subsequent "international panel" review examined "the integrity" of CRU's research and that also cleared the unit.

"We saw no evidence of any deliberate scientific malpractice in any of the work of the CRU and had it been there we believe that it is likely that we would have detected it," the review concluded. "Rather we found a small group of dedicated if slightly disorganised researchers who were ill-prepared for being the focus of public attention. As with many small research groups, their internal procedures were rather informal."

Given the global importance of this work it’s clear that groups such as this must be better resourced and supported to carry it out thoroughly.

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