Memorandum submitted by Professor Peter
Cox (CRU 29)
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
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 1,000 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
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 appropriateit 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
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 (ie 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