Memorandum submitted by Manchester School
of Management, University of Manchester Institute of Science and
The Manchester School of Management (MSM) at
UMIST undertakes research into the management of climate change
as part of its Environmental Management and Policy Programme.
Between 1992 and 1998, Dr Simon Shackley, a lecturer in the School,
conducted research on the use of climate change science in policy
making in the UK, USA, Netherlands, Sweden and Germany. In 1993
he spent 4 months working at the Hadley Centre of the UK Meteorological
Office to explore the science/policy interface. He has also visited
the key climate modelling centres in the USA and Germany, and
has attended five meetings of the Intergovernmental Panel on Climate
Change (IPCC). He has written a number of papers on the subject
of climate modelling, scientific assessment and the science/policy
interface, copies of which can be made available to the Committee
on request. (A bibliography is included at the end).
The Government has been advised of potential
alternative explanations to the extent that such alternatives
have been debated during dialogue with the Hadley Centre and within
the scientific working group (WGI) of the IPCC. Extensive debate
on alternative explanations has taken place at the IPCC due to
involvement in that process of some nations and organisations
which are (often for political or economic reasons) searching
for alternative explanations to the consensus view that the balance
of evidence suggests a discernible human influence upon global
climate. Indeed the Policy Makers Summary and Technical Summary
of the IPCC are much more extensively reviewed than the average
paper published in a scientific journal. Associated with such
a process is critical scrutiny of climate modes, since these provide
much of the foundation for concern over anthropogenic climate
change. The stakes around climate change are very high for many
organisations and nations, hence such models are the recipients
of much scrutinyfrom both sides of the argument. Within
the UK, the Government relies heavily upon the Hadley Centre for
advice and confidence in climate models, which reflects the latter's
pre-eminence in climate change research. There is probably value
for the Government in hearing advice from a wider university and
specialist community, at least as a "checks and balance"
mechanism. Development of methods for critically appraising climate
models has been rather slow, especially around uncertainty and
model behaviour analysis, and such investigation could be further
encouraged by Government. In the end, however, we have to accept
that any knowledge or explanation of climate change will be uncertain
in the short to medium (and perhaps even long) term, so the issue
is not "can we prove it?", but rather "how do we
decide what is the most likely explanation at the present time
given scientific uncertainty?"
(A): The extent to which the Government has been
advised of potential alternative explanations, how these alternatives
have been assessed and what conclusions have been drawn.
3. The Relevance of the Hadley Centre and
The provision of formal advice on the science
of climate change to the Government has come primarily from Working
Group 1 of the IPCC. In practice, however, the main route by which
the Government has obtained its interpretation of the scientific
advice is through the Hadley Centre. The Hadley Centre and WGI
of the IPCC are closely identified, hence the scientific assessment
and advice from both organisations is very closely aligned. The
close relationship between the Hadley Centre and the WGI of the
IPCC arises from three factors: the active involvement of individual
Hadley Centre scientists in the WGI, hosting of the WGI secretariat
within the Hadley Centre, and Sir John Houghton's chairmanship
of the WGI. To some extent then, question (A) requires an investigation
of whether the WGI of IPCC has considered potential alternative
4. The Role of the Hadley Centre
The scientists at the Hadley Centre have, on
occasion, been asked by Government officials to comment on alleged
alternative explanations which have been reported in the scientific
and popular presses. (Examples include requests for comments on
the ideas of Dr Sherwood Idso, Professor Richard Lindzen, and
analysis of counter evidence of a warming trend in sensitive areas
such as the polar regions, etc). On other occasions, the Research
Coordinator at the Hadley Centre has volunteered information to
Government officials on alternative explanations and supporting
evidence which has been presented in the scientific literature,
especially when such reports may find their way into the popular
media. It is not known whether there is a more formal mechanism
by which the Hadley Centre can communicate and explore alternative
explanations with Government. More important than a formal mechanism,
perhaps, is a close and cooperative relationship between officials
at the Hadley Centre and those in relevant Government Departments.
We have evidence that frequent face-to-face and remote communications
between Government Officials and Hadley Centre scientists has
many benefits for the interpretation of scientific understanding
and new knowledge. This kind of relationship between climate scientists
and government officials is rarely found elsewhere in the world
and has been an important factor in the Government's readiness
to accept and act upon the problem of climate change. The less
coordinated scientific assessment process in the USA, for example,
has weakened the thrust of the scientific consensus developed
within the WGI of IPCC. At the same time, however, the US process
reflects the more fragmented political system in that country.
5. Role of Other Scientists
Government has also relied, though to a lesser
extent, upon advice from selected and eminent individual scientists
outside of the Hadley Centre. It is possible that some greater
involvement by such scientists might have raised more questions
about, and produced different assessments, of alternative explanations.
6. Extended Peer Review at the IPCC
The WGI of the IPCC has considered and assessed
alternative explanations through the process of what can be known
as "extended peer review" (after Funtowicz & Ravetz).
Extended peer review involves non-specialists in the assessment
of scientific knowledge for policy, including Government officials
and representatives of Non-Governmental Organisations such as
environmental and development groups, individual companies and
industrial associations. The Plenary Sessions of the WGI involved
extended peer review, through suggestions and subsequent debate
from national delegations and non-governmental organisations on
how the text of the Policy Makers Summary and Technical Summary
should be modified.
7. Political Differences at the IPCC Encouraging
Scrutiny of the Science
The inevitably wide range of political viewpoints
represented by the member countries of the IPCC makes it likely
that scientific opinions which challenge the consensus viewpoint
find expression during the deliberations of the IPCC. Saudi Arabia
and Kuwait, for instance, have tended to take a negative stance
towards the IPCC making strong scientific claims, believing that
this will encourage tough emission reduction targets which will
impose high costs upon their domestic economies. Such countries
have tended to look to scientific arguments and explanations for
climate change which negate the role of anthropogenic influences.
This diversity of political interests has allowed alternative
scientific viewpoints to be expressed within the IPCC. (This is
an addition to the expression of dissenting voices within the
full chapters of the IPCC, a practice which has increased since
the IPCC first reported in 1990.) The delegates of the UK Government
play an active role in the IPCC WGI Plenary sessions. Hence, they
are also exposed to alternative explanations, and arguments for
and against, during such deliberations, not only from UK scientists,
but from an international community of scientists, policy advisors
8. A Case Study from Madrid 1995
In 1995, the IPCC WGI Plenary in Madrid arrived
at the important new statement that: "The balance of evidence
suggests a discernible human influence on global climate"
(Climate Change 1995: The Science of Climate Change, CUP,
Cambridge, page 4). During the Plenary there was dissent on the
sentiment behind this statement from Kuwait and Saudi Arabia,
who influenced the perception of the Group of 77 (less industrialised
countries). As a consequence, agreement was not possible during
the Plenary and the Chairman proposed that the issue be deferred
to a small working group of key IPCC scientists and national delegates.
This working group included Kenya, representing the G77 nations.
During the three hour meeting of the working group, the different
explanations of the spatial and temporal pattern of warming and
cooling evident in the observations were discussed and assessed.
One representative of an EU nationa scientist by backgroundexplicitly
required the scientists to identify alternative explanations and
to defend their position that the balance of evidence suggested
a discernible human influence on global climate. As a consequence
of this process, the Kenyan delegate was convinced of the legitimacy
of the "discernible human influence" argument, and that
in turn swayed the position of the G77 in favour of acceptance.
9. Peer Review of IPCC More Thorough Than
Conventional Peer Review
It is, of course, difficult to say whether the
alternative explanations have always been as thoroughly debated
as they should or could have been. The above account suggests,
however, that there are opportunities in the existing processes
for alternatives to be expressed and discussed. Indeed, the Policy
Makers Summary and Technical Summary of the IPCC reports are amongst
the most scrutinised scientific documents ever produced. Unlike
a scientific paper in a journal which is typically reviewed by
between two and four peers, the IPCC reports (and especially the
summaries) have been thoroughly reviewed and commented upon by
hundreds of individuals and organisations. The introduction of
an independent scientist to ensure that the lead authors of the
main chapters of the forthcoming IPCC Third Assessment Review
have taken proper account of the peer reviewers' comments is a
welcome and necessary addition to the overall peer review process.
10. Existence of Different Research Paradigms
The ability to assess alternative explanations
is, in part, limited by the existence of different research paradigms.
Climate models make certain assumptions about what variables determine
the climate, not all of which can be confirmed by evidence (Shackley
et al 1998). (For example it is assumed by most climate modellers
that the climate system, unlike the weather, is not chaotic.)
Alternative explanations, which do not rely upon climate models,
rely upon other untested, and often untestable, assumptions or
have major gaps in their explanations. We have to accept that
any knowledge or explanation of climate change will be uncertain
in the short to medium term, so the issue is not "can we
prove it?", but rather "how do we decide what is the
most likely explanation at the present time given scientific uncertainty?"
Despite all their limitations and uncertainties, climate models
and their underlying physical theory, do seem to be the most robust
form of knowledge for providing information on anthropogenic climate
change at present. Since this judgement may change over time,
given new evidence and new theories, it is vital that alternative
explanations are constantly scrutinised and encouraged into the
(B) What critical appraisal there has been
of models predicting climate change, increasing concentrations
of carbon dioxide, and other potential drivers.
11. The Critical Appraisal of Climate Models
In general, the IPCC process and its extensive
peer review and extended-peer review processes, has guaranteed
much critical scrutiny of climate models. For example, at the
IPCC WGI Plenary in Madrid in 1995, the issue of whether and how
"flux adjustment" limited the reliability of the climate
change scenarios from General Circulation Models (GCMs) was raised
by industrial organisations (see Shackley, et al 1999).
In response to widespread concern from industry and many scientists
about the use of flux adjustments in GCMs, climate modelling centres
have worked hard to identify the model errors which result in
the need for such adjustment factors. Hence, in this case, critical
scrutiny has probably resulted in the modellers taking the issue
more seriously than would otherwise have been the case. There
seems little doubt that the critical scrutiny of climate modelling
has grown with their role in providing support for the existence
of anthropogenic climate change. As another example, Professor
Lindzen's criticisms of how GCMs represented the upper troposphere
were accepted by at least some climate modellers, who then attempted
to address this problem in their models. As suggested in paragraph
(9), however, the arguments over climate models will never by
fully resolved as there will always be uncertainty in a highly
complex, open system such as the climate. It is likely that there
will always be some scientists who do not accept the projections
from climate models, because they do not accept all or some of
the assumptions which are necessary in constructing a climate
12. Analysis of Uncertainty and Model Behaviour
One area where there could be more scrutiny
of climate models and carbon cycling models is in the analysis
of uncertainty. Stochastic methods such as Monte Carlo Simulation
hold out much potential for better understanding of uncertainty,
but have rarely been applied to GCMs (in part for technical reasons).
Other methods for better exploring the behaviour of models also
deserve more attention. Parkinson & Young showed that the
behaviour of a complex 23rd order non-linear simulation model
of the carbon cycle could be almost exactly reproduced by a much
simpler fourth order linear model (reported in Shackley et al.,
1998, pages 180-182). This finding suggested that the original
model included much detail that did not influence the model's
behaviour. In general, rather little is known about the interactions
which produce the outputs from GCMs. It is encouraging to find
that the importance of uncertainty analysis using ensemble runs
is now more accepted within the UK climate modelling community.
Other approaches to uncertainty analysis, such as expert elicitation
(eg through identification of subjective probability distributions
or "Delphi" methods) have been explored much more in
the USA than in the UK, and there would be value in this activity
increasing in the UK.
(C) The degree of Government agreement with
scientists in relevant specialisations regarded accepted explanations
of climate change.
12. The Government follows the consensus
position established by physical-science oriented climatologists.
Some meteorologists take a somewhat different viewpoint especially
as regards the adequacy of existing GCMs, though generally they
also accept the IPCC's consensus. Even if existing GCMs are not
regarded as very reliable, there are a number of other reasons
for supporting the position of the IPCC (including historical
observations and their correlation, physical theory and other
types of climate model). A small number of climatologists from
a geographical tradition are more sceptical of the ability of
climate models to simulate the current climate and to produce
scenarios of future change. Some of these scientists are, arguably,
working in a different scientific paradigm to the climate modellers.
For example, some of them believe that the climate system is too
complex to be modelled using mathematics and computers. Other
dissenters include a few astronomers and geologists, though again
many in these disciplines accept the IPCC consensus.
23 December 1999
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B (1999) "Adjusting to Policy Expectations in Climate Change
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