IPCC: the dangers of enforcing ‘consensus’

The joint award of this year’s Nobel Peace Prize to the Intergovernmental Panel on Climate Change (IPCC) and former US vice-president Al Gore has been greeted positively by commentators internationally. Where there has been criticism, it has been directed at the decision to give Gore a share of the award. But what about the IPCC?

Writing in The Times (London), Ross Clark suggests that Al Gore is something of a climate change alarmist and an unsuitable recipient of the award. Clark cites as evidence last week’s ruling by the High Court in London that Gore’s film, An Inconvenient Truth, must not be shown in schools without a ‘health warning’ about the film’s bias and factual inaccuracies. By contrast, the IPCC is seen to be more sober and the real authority on the subject:

‘Most brazen of all, Gore claims that sea levels could rise by 20 feet “in the near future” – vividly illustrated in the film with a simulation of Manhattan disappearing beneath the waves. In fact, the IPCC… believes that sea levels will rise by less than 18in over the next 100 years, and that it would take several millennia for sea levels to rise by 20 feet.’ (1)

Similarly, writing in the Boston Globe, Bjørn Lomborg, the notorious ‘sceptical environmentalist’ whose new book, Cool It, argues for a less heated debate on global warming, comments that the Nobel Peace Prize ‘justly rewards the thousands of scientists of the United Nations Intergovernmental Panel on Climate Change’ who are ‘engaged in excellent, painstaking work that establishes exactly what the world should expect from climate change’. Lomborg strongly implies that Gore has indulged in fear-mongering and exaggeration – in contrast to the IPCC, whose estimates and conclusions are ‘grounded in careful study’ (2).

However, I would argue that the way in which the IPCC is being turned into a body beyond criticism, whose pronouncements cannot be challenged without critics facing accusations of ‘global warming denial’, is a far greater threat to democratic debate and good decision-making than Gore’s self-evident alarmism. The IPCC is treated as a priestly body that rises above what is seen as the petty squabbling of politicians and individuals too selfish to reduce their carbon footprint; as the sole repository of truth, given by the ‘scientific consensus’. It is time to start asking some tough questions of the IPCC and the role it plays before we continue along these lines.

The emphasis that the IPCC places upon consensus would be one good place to start. For example, John Zillman, president of the World Meteorological Organisation (WMO) from 1995 to 2003 (one of the IPCC’s two sponsoring bodies), and someone very much involved in the establishment of the IPCC, wrote a candid article in August 1997 titled ‘The IPCC: a view from the inside’ (3).

In the article, Zillman notes that ‘although there were already mechanisms in place’ for taking stock of the state of knowledge of greenhouse gases, ‘the WMO Congress decided that a more broadly representative mechanism was needed to prepare the authoritative advice needed by governments’. As is now well known, this mechanism involves scientists and government officials from participating countries agreeing, line by line, the wording of key summary documents for policymakers of periodic Assessment Reports authored by scientists. Whilst pointing out his overall support for the scientific integrity of the work of the IPCC, Zillman’s paper drew particular attention to the problems and pressures of this consensus approach:

‘[T]here has been unusually intense pressure for consensus to be achieved even when many individual participants clearly felt extremely uncomfortable with signing on to the “consensus” language. These pressures became extreme in some of the late night meetings when the time for achievement of consensus was running out, delegations were exhausted and dissenting individuals were subject to considerable peer pressure to agree in order to avoid the stigma of being seen to have prevented the IPCC from achieving a consensus report.’ (4)

The pressure to achieve consensus remains very much a part of the IPCC today – a fact made obvious by the press reports of the late night meetings proceeding the publication of the three summary reports of the IPCC’s work this year. And in the run-up to the publication of its final report – Fourth Assessment: The Synthesis Report – to be finalised at a conference in mid-November, the IPCC is pushing the significance of this consensus strongly.

For example, take the following advert for the forthcoming Synthesis Report on the IPCC’s website home page:

Who could possibly argue with such an array of international expertise all in agreement with one another? But in many ways, these figures are misleading. The expertise of those contributing to IPCC processes is unsurprisingly hugely varied, necessarily covering a vast array of disciplines and fields of research. So in reality, the ‘one report’ brings together distinct and discrete areas of expertise addressing often related but distinct questions – the experts on cloud formation, for example, will have little expert opinion to input into the discussion of the impact of global warming on biodiversity.

The contrast between the impression of thousands of scientists acting as one and the reality of the IPCC process was highlighted in an analysis recently conducted by John McLean, titled Peer Review, What Peer Review? and published by the Science and Public Policy Institute. Analysing information secured from the IPCC under a US Freedom of Information request, McLean examines the level of review activity associated with the IPCC’s key Working Group 1 (WG1) report that assesses ‘The Physical Science Basis’ of climate change.

Looking at the comments made by the scientific reviewers for the Second Revision of the Draft WG1 report, McLean found that a total of 308 reviewers commented on the Second Revision, which was the penultimate draft. According to McLean ‘only 32 reviewers commented on more than three chapters and just five reviewers commented on all 11 chapters’. There were 143 reviewers (46 per cent) who commented on just one chapter and 71 reviewers (23 per cent) who commented on two chapters.

Such a tally does not itself demonstrate a faulty peer review process. However, McLean certainly seems to have a point when he draws attention to the gap between the perception the IPCC wishes to create of thousands of scientists in unity in one report, and the reality of a report comprised of many distinct parts, each contributed to and commented on by a far smaller number of scientists with knowledge of a specific field.

For example, McLean finds that for chapter nine, a chapter that he describes as ‘the key science chapter’ where ‘the IPCC concludes that “it is very highly likely that greenhouse gas forcing has been the dominant cause of the observed global warming over the last 50 years”’, only 62 reviewers provided any comments on the chapter at all.

McLean argues that ‘simple corrections, requests for clarifications or refinements to the text which did not challenge the IPCC’s conclusions are generally treated favourably, but comments which dispute the IPCC’s claims or their certainty are treated with far less indulgence’. He concludes that ‘the notion of hundreds of experts diligently poring over all chapters of the report and providing extensive feedback by way of peer review to the editing teams is here demonstrated to be an illusion’.

It may turn out to be the case that most of the observed global warming over the last 50 years has been man-made. This may, in turn, imply the need for some action on the part of society. However, there is much to be debated – both in terms of the complexities of what is and is not known scientifically about climate change, and in terms of political discussion about how we wish to respond to this knowledge. Yet increasingly, the IPCC is not a positive mechanism for throwing light on the situation and allowing perspectives to be worked through. Instead, those who wish to conduct such debates – unless on the extremely narrow terms laid down by the IPCC – are being portrayed as beyond the pale. Democratic debate is being stifled rather than encouraged for fear that people will come to the wrong opinions and make the wrong choices.

The IPCC, with its hyping of the ‘scientific consensus’, is an important expression of the way in which ‘expertise’ is being used to supplant full and open debate. As such it needs to be critiqued, not placed on a pedestal, if we are to have any chance of making good decisions and benefiting from democratic debate in the future.

Tony Gilland is chairing the Battle of Ideas debate The politics and science of climate change on Sunday 28 October 2007 at the Royal College of Art in London. The speakers are: Professor Mike Hulme, University of East Anglia; Joe Kaplinsky, science writer and researcher; Professor Chris Rapley CBE, director of the Science Museum; and Hans von Storch, director, Institute for Coastal Research.