Memorandum submitted by Professor Peter Cox (CRU 29)

Declaration of Interests

I am a climate scientist who was a lead-author on the last IPCC Working Group I report, so I have an interest in ensuring the integrity of climate change science. I know of Prof Phil Jones and Prof Keith Briffa through their work, and also through a recent grant proposal that we were all involved in.

1) What are the implications of the disclosures for the integrity of scientific research?

I don't doubt the integrity of the research carried-out at the Climatic Research Unit (CRU), as I have first-hand knowledge of the scientists involved. However, I am concerned that public confidence in the science of climate change has been undermined by the email leak.

I believe that many of the issues highlighted in the media concerning the emails have now been explained. The initial focus was on the use of the word 'trick' by Prof Jones to describe the technique used to merge the climate proxy records (mostly from tree-rings) with the direct instrument record (from thermometers). The use of the word 'trick' would have been ill-advised if the author had known that the emails were to be made public. However, he did not, so I think this colloquialism is understandable. I think many emails could be similarly misinterpreted if taken out of context in this way.

There remains an issue of how to interpret tree-ring data in the recent past (which is sometimes called the 'divergence problem'), but this merely relates to how temperatures are reconstructed for the last 1000 years based-on the direct measurements since the mid-19th century. It does not in anyway undermine the direct evidence of global warming in the industrial era.

More serious are the allegations concerning the reviewing of scientific papers and the possible deliberate exclusion of papers from the IPCC report. In at least one case (a paper for which Prof Keith Briffa was the reviewing Editor) the email exchange has already been explained. It seems that the original reviewer had already rejected a paper and Prof Briffa was merely asking the reviewer for a proper justification of the rejection. Keith Briffa is a man who encourages vigorous debate, rather than suppressing it, so I don't doubt this explanation. Rejecting papers because they are scientifically flawed is of course quite appropriate - it is how peer review maintains the integrity of the science published in peer-reviewed journals.

I suspect that other allegations that particular papers were 'blocked', for reasons other than scientific merit, will also turn-out to be false. However, this is something for the Inquiry to ascertain. The integrity of the peer-review process in science is at least as important as the public's perception of climate change.

2) Are the terms of reference and scope of the Independent Review announced on 3 December 2009 by UEA adequate (see below)?

In general yes, but I believe the Inquiry should hear evidence on the reviewing of scientific papers and the exclusion of papers from the IPCC report. It will be critical to determine whether these decisions were carried-out on the basis of scientific merit alone, for the reasons outlined above.

3) How independent are the other two international data sets?

I am not an expert on climate datasets, but it seems inevitable to me that these will be based on similar data sources, as there is only so much climate data. However, I wish to reiterate that the concerns raised over the 'record' of past temperatures relate to the interpretation of proxy data (especially from tree-rings), and not to the direct observational record from thermometers.

It is perhaps unsurprising that the major climate data centres agree on the extent of recent global warming given that they are based on these similar direct measurements (measurements that are not in doubt). However, I believe that each centre independently processes the raw thermometer data, suggesting that the signal of climate change in the direct observations is very robust (..as well as being consistent with our scientific understanding of the greenhouse effect and the climate system).

Our knowledge of natural climate variations prior to the instrument record (i.e. before the mid 19th century) is much less certain. However, the evidence of recent climate change, and its impact on natural systems, remains overwhelming (as outlined in the IPCC reports). It would be tragic if the CRU email hack undermined public confidence in the science of global warming at a time when we need to be pulling together to deal with the problem. I hope that the Inquiry is able to clear-up some of the misunderstandings which have emerged since the breach of security at UEA.

Professor Peter Cox
Professor of Climate System Dynamics
School of Engineering, Computing and Mathematics
University of Exeter

February 2010