Select Committee on Science and Technology Third Report


Policymakers' use of scientific advice


27. Climate change is yet another area where policymakers have to deal with considerable uncertainty in scientific advice. The science of climate change is in many ways uncertain, though understanding is growing rapidly. Policymakers prefer certainty - as the Minister told us, "when you have to deal with the Treasury, ... it is much better to speak in terms of certainties than in terms of weighted probabilities"[74] - but, in this area, policymakers appear to have accepted that there is an unavoidable element of uncertainty. There does not appear to have been pressure on scientific advisers to suppress uncertainty or divergent views, although - as we have seen - there is some concern that scientists of dissenting views are not heard sufficiently. The IPCC has developed a clear formula for communicating degrees of uncertainty in its assessments. In its summaries, it uses "virtually certain " to denote a greater than 99% chance that a result is true; "very likely" to denote a 90-99% chance; "likely" to denote a 66-90% chance; "medium likelihood" to denote a 33-60% chance; "unlikely" to denote a 10-33% chance; "very unlikely" to denote a 1-10% chance; and "exceptionally unlikely" to denote a less than 1% chance. For example, in the Third Assessment Report of Working Group I, the IPCC states that "most of the observed warming over the last 50 years is likely to have been due to the increase in greenhouse gas concentrations" and that "it is very likely that the 20th century warming has contributed significantly to the observed sea level rise".[75] The formula used by the IPCC to communicate degrees of uncertainty could usefully be adopted in other scientific advice.

28. Climate change is a prime example of an area in which the precautionary principle is being applied. Even though there is considerable uncertainty, the consequences of inaction are sufficiently serious to require action. In this case, some action is being taken to curb greenhouse gas emissions, even though it is not absolutely certain that greenhouse gases cause climate change, because the consequences of inaction for the climate may be great. And it appears that the precautionary principle is being applied by scientists as well as policymakers. As Dr Shackley told us, "there is, as well as a common understanding of the science, also an element of a precautionary ethic in the work of, say, the IPCC in the sense that ... we should be erring on the side of caution when it comes to issues like climate change".[76] A principle of proportionality can also be identified: the more severe the implications, the more necessary that we respond, despite the uncertainty. We urge the Government to demonstrate that it is observing the precautionary principle, not just in its policy on emissions, but in responding to the threatened effects of climate change - for example, in flood prevention measures and planning policy - and in alternative transport strategies and in investing in research and development in renewable energy.

29. Climate change is also an example of the limits of the precautionary principle. The developed countries agreed at Kyoto to a 5.2% reduction in greenhouse gas emissions, but it remains to be seen whether they will be prepared to accept the 60, 70 or even 90% reductions which are being suggested to be necessary to have a significant impact on greenhouse gas concentrations, while allowing for industrial growth by the developing countries. As the Minister acknowledged, the implications of emission reductions of that size are "absolutely mind-blowing".[77] The Minister told us that he had asked the Department to produce an outline of what might be involved with a reduction of 60% in CO2 in the UK or any industrialised country; and that he suspected that "it will be sufficiently worrisome that the Department will be extremely unwilling to publish it". Even if the Minister's comment was lighthearted, this indicates the severity of the action required. It is most important that the Department's analysis of the changes required to reduce CO2 emissions by 60% be published to inform the public debate on climate change. In reality, the need for action is balanced against the political, economic and social consequences of action - particularly where that need for action is uncertain. The more unpalatable the action required, the less likely it is that the precautionary principle will be applied. Policymakers in this country and abroad ought to resist the temptation to hide behind scientific uncertainty in order to avoid introducing the very great changes required to reduce greenhouse gas concentrations significantly.

30. On the more positive side, there are potentially large economic benefits for those who anticipate global action on climate change by developing technologies and products for reducing greenhouse gas emissions or for exploiting alternative sources of energy. In our forthcoming inquiry into Wave and Tidal Energy we intend to examine the potential of one form of renewable energy. There are considerable commercial opportunities for UK science and technology, in responding, together with industry, to the challenges of climate change.

31. One of the uncertainties of climate change is the possibility of rare but cataclysmic natural events, such as a major volcanic eruption, which could have a dramatic effect on climate, more than outweighing anthropogenic factors contributing to global warning. Evidence from the Geological Society of London expressed concern about the extent to which the Government had addressed the implications of rapid short term changes in weather and climate caused by large volcanic eruptions.[78] Volcanic eruptions have had a significant effect on the weather in the past, reducing temperatures worldwide for a number of years.[79] It is hard to see how Governments could effectively plan for such unpredictable events, though it is clearly a possibility of which they should be aware. We welcome the Minister's assurance that the arrangements for dealing with natural disasters are under review.[80]


32. Though the DETR has lead responsibility in the Government's response to climate change, issues arising from climate change involve many Government Departments. The Ministry of Agriculture, Fisheries and Food is involved in assessing the implications of climate change for agriculture and coastal defence. The Department of Trade and Industry is involved in managing energy policy. The Treasury is involved in determining fiscal policies to discourage greenhouse emissions. The Office of Science and Technology is involved through its funding of scientific research through the Research Councils. The DETR's memorandum states that climate change policy is co-ordinated through the Inter-Departmental Liaison Group, though its exact role is unclear to us.[81] Effective interdepartmental co-ordination on climate change is essential.

33. Managing the effects of climate change - flooding and coastal erosion, for example - also involves local government, which also requires clear and authoritative scientific advice. The Institute of Biology warned that "some local government administrations appear less aware of scientific advice relating to climate change and this is likely to result in costs on society".[82] Scientific advice on climate change and its management must be communicated effectively across both central and local Government.


34. Climate change is an area in which, broadly speaking, scientific advice to Government appears to be working well. Scientific advice is well integrated in policy making, largely because of the very close links which exist between the DETR and the Hadley Centre. Through the reports of the IPCC, and because of the close links between the Hadley Centre and the IPCC, the Government is well informed about the latest, and most authoritative, scientific opinion from across the world. The way in which the IPCC operates ensures that the advice it gives to Governments is validated by extensive peer review. It is partly because of the openness of the IPCC process that - in marked contrast to other areas of scientific advice - the advice which the Government gets on climate change is not a matter of public concern or suspicion.

35. However, there is some concern that - as in other areas - Government gives ear only to the scientific establishment or consensus view, and that it is not sufficiently open to advice from scientists of dissenting opinion. There are concerns that it relies overly on the Hadley Centre and on its climate models, and is less open to advice from those working in other fields, notably in study of the palaeoclimate. While the full reports of the IPCC incorporate the views of scientists of all opinions, the policymakers' summaries reflect the consensus view that human activities are affecting the climate. It is important that the Government should hear also from those respected scientists who are sceptical to varying degrees of the anthropogenic nature of climate change. There are also concerns about the coherence and comprehensiveness of the national research programme on climate change, and particularly about the availability of advice on the biological effects. The research programme must anticipate the need for advice in future years and should be broad enough to address new and unforeseen issues as they arise.

36. It is at least partly because of the close links between the DETR and the Hadley Centre that the UK Government was one of the first in the world to recognise the threat of climate change and to press for international action to address it. Climate change is an area where unilateral action by single countries is of limited value: international agreement is vital. The IPCC has played a very important part in forging an international consensus on climate change, among both scientists and Governments, though it is regrettable that the USA is yet to appreciate the necessity of early action to reduce its greenhouse gas emissions. We urge the UK Government to press for international agreement on the rules for implementing the Kyoto Protocol when the negotiations are resumed in the summer of 2001.

37. We believe that the IPCC model could usefully be adopted for scientific advice in other policy areas of global significance, for example on genetically modified organisms and ocean pollution.

Q 148. See also Q 92. Back

75   Third Assessment Report: Summary for Policymakers. Back

76   Q 84. Back

77   Q 152. Back

78   Evidence, p 56, paragraph III. Back

79   Evidence, p 59, paragraphs 20-25; Q 114. Back

80   Q 159. Back

81   Evidence, p 41, paragraph 41. Back

82   Evidence, p 66, paragraph 2 (v); p 69, paragraph 21. Back

previous page contents next page

House of Commons home page Parliament home page House of Lords home page search page enquiries index

© Parliamentary copyright 2001
Prepared 21 March 2001