Select Committee on Science and Technology Minutes of Evidence

Memorandum submitted by Manchester School of Management, University of Manchester Institute of Science and Technology (UMIST)

1.  Introduction

  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).

2.  Summary

  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 scrutiny—from 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 IPCC

  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 explanations.

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 and NGOs.

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 nation—a scientist by background—explicitly 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 debate.

(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 model.

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


  Shackley, S (2000) "Epistemic Lifestyles in Climate Change Modelling", and Climate Change Science and Policy in the UK: "An over-identified Scientific Problem in a Context of Political Intransigence", Paul Edwards and Clark Miller (eds), Changing the Atmosphere, MIT Press, Cambridge, Mass, in print.

  Shackley, S, Risbey, J, Stone, P and Wynne, B (1999) "Adjusting to Policy Expectations in Climate Change Science: An Interdisciplinary Study of Flux Adjustments in Coupled Atmosphere Ocean General Circulation Models", Climatic Change 43: 413-454.

  Shackley, S (1999), "Rolling out the climate change policy lessons", Development Research Insights, Issue 30, June, 2-3.

  Shackley, S, (1998) Guest Editor and "Introduction to Special Section on the Use of Models in Appraisal and Policy-Making", Impact Assessment and Project Appraisal, 16(2), 81-89.

  Shackley, S, Risbey, J and Kandlikar, M (1998) "Science and the Contested Problem of Climate Change: A Tale of Two Models", Energy and Environment, 8: 112-134.

  Van der Sluijs, van Eijnhoven, J, Shackley, S and Wynne, B, "Anchoring Devices in Science for Policy: The Case of Consensus Around Climate Sensitivity", Social Studies of Science, 28(2), 1998, 291-323.

  Shackley, S, Young, P., Parkinson, S and Wynne, B (1998) "Uncertainty, Complexity and Concepts of Good Science in Climate Change Modelling: Are GCMs the Best Tools?", Climatic Change 38: 155-201.

  Shackley, S, and Wynne, B (1997) "Global Warming Potentials: Ambiguity or Precision as an Aid to Policy?", Climate Research 8: 89-106.

  Shackley, S (1997) "The Intergovernmental Panel on Climate Change: Consensual Knowledge and Global Politics", Global Environmental Change 7(1), 77-79.

  Shackley, S (1997) "Trust in Models", in Michael Redclift and Graham Woodgate, The International Handbook of Environmental Sociology. Edward Elgar, Gloucester, 237-260.

  Shackley, S and Wynne, B (1996) "Representing Uncertainty in Global Climate Change Science Policy: Boundary-Ordering Devices and Authority", Science, Technology and Human Values 21 (3), 275-302.

  Shackley, S and Wynne, B (1995) "Global Climate Change: the Mutual Construction of an Emergent Science-Policy Domain", Science and Public Policy 22 (4), 218-230.

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