This essay by Prof. Mike Hulme appears in a document entitled ‘Future directions For Scientific Advice in Whitehall’ published in April this year (coincident with the appointment of Sir Mark Walport as chief scientific advisor).
LESSONS FROM THE IPCC:
DO SCIENTIFIC ASSESSMENTS NEED
TO BE CONSENSUAL TO BE
AUTHORITATIVE?
Mike Hulme
One of the common public expectations of science is that it speaks
authoritatively about the way the physical world works and thereby what the
physical consequences of different human actions and policy interventions
are likely to be. Science and scientists are believed to offer something
different to public life compared to that offered by politicians, journalists,
lawyers, priests or celebrities. But what is meant by ‘authoritative’? And
how does scientific practice best earn and maintain its authority in the
face of public challenge and scepticism? In these few remarks, I want to
explore one important dimension of scientific authority-building, namely
the interplay between the ideas of consensus and dissensus. And I want to
do this using the example of the UN’s Intergovernmental Panel on Climate
Change (the IPCC). The question I wish to answer can be put simply:
does the pronouncement of a scientific consensus on an issue such as
climate change increase or weaken the authority of science? And for whom
exactly are such pronouncements effective – scientists, different publics,
policymakers, politicians?
Claiming consensus
The IPCC has made a very specific claim regarding its consensus-making
character, as too have many commentators outside the IPCC – whether
politicians, lobbyists, advocates or critics. In the foreword to the Working
Group I report on the physical science of climate change in the 1st IPCC
Assessment, published in 1990, the Co-Chair Sir John Houghton wrote “…
peer review has helped ensure a high degree of consensus amongst
authors and reviewers regarding the results presented.”1 From the
very beginning then, the IPCC has sought and rhetorically delivered a
consensus on climate science. Thus we see in November 2007, just ahead
of the publication of the IPCC’s 4th Assessment Synthesis Report, the IPCC
promoting the authority-making nature of its consensus processes: “2,500+
scientific expert reviewers; 800+ contributing authors; and 450+
lead authors; from 130+ countries; 6 years work; 4 volumes; 1 report.
The core findings of the three volumes integrated in the most policyrelevant
scientific document on climate change for the years to come.”
The sheer weight of expertise compressed into one report is itself a claim to
authority.
This association between consensus and authority is then exploited, not
surprisingly, by social and political actors outside the IPCC. The fallacy,
pushed particularly by some of the climate change campaigning NGOs
from the early 1990s onwards, is that the stronger the climate consensus,
the easier it is for lobbyists to use science to advance their own goals and
objectives. The front page headline from The Guardian newspaper on
27 January 2007, just before the IPCC’s 4th Assessment Working Group I
report was released in February, reflects this: “UN’s vast report will end
the scientific argument. Now will the world act?” Or again we can see
political actors picking up cues about consensus equating to authority, as
in this example from Australian Prime Minister Kevin Rudd. In a speech on
6 November 2009, just before COP15 in Copenhagen, Rudd announced:
“This is the conclusion of 4,000 scientists appointed by governments
from virtually every country in the world … Attempts by politicians
in this country and others to present what is an overwhelming global
scientific consensus as little more than an unfolding debate … are
nothing short of intellectually dishonest. They are a political attempt to
subvert what is now a longstanding scientific consensus.”
Is scientific consensus needed?
But is the IPCC right to be aiming for a scientific consensus and are its
promoters right to be proclaiming IPCC consensus as an end to argument?
Or to ask the question more generally, when seeking to be authoritative on
complex issues of public policy importance should scientific assessments be
issuing consensus statements?
In his exploration of political theory, Jon Elster, the Norwegian social
theorist, remarked: “I would in fact tend to have more confidence in the
outcome of a democratic decision if there was a minority that voted
against it, than if it was unanimous”.2 If this is true of a democracy, then
could it also be true of science? Would non-scientists have more confidence
in climate science if there was a minority view – for example about the
evidence of attribution or change to human influences or about future
climate risks – that was officially recognised by the IPCC, rather than the
existing mode of climate science being presented as an all-encompassing
consensus? In the article in which Elster is quoted, philosopher of science
John Beatty and political theorist Alfred Moore develop exactly this
argument, and I believe it applies well to the case of climate change and the
IPCC.3
In favour of consensus
The argument in favour of consensus as authoritative is that it reflects what
science supposedly is uniquely disposed to be good at: applying rules of
reasoning and inference which lead unambiguously and universally from
evidence to conclusion. The same evidence presented to the same disciplined
mind leads to precisely the same conclusion. In this view, a lack of consensus
would undermine the authority of science because it might suggest either that
conflicting conclusions had been reached prematurely or that personal or
cultural biases and values had protruded into the reasoning process.
This is the position that seems to be implicitly assumed by many protagonists
in the climate change debate, whether they be mainstream or critical voices.
It was the view expressed by Sir John Houghton for example in the foreword
cited above. His comments on consensus were immediately preceded by the
observation that a minority of scientific opinion had been excluded from the
report and that the resulting consensus therefore underwrote its authority:
“Although … there is a minority of opinions which we have not been
able to accommodate, the peer review has helped ensure a high degree
of consensus amongst authors and reviewers regarding the results
presented. Thus the Assessment is an authoritative statement of the
views of the international scientific community at this time”.4
It is also the view of many critics of the scientific mainstream who assert
that science properly conducted – through unbiased reasoning processes
– should lead to unanimous consent. By pointing out the mere existence
of minority dissenting positions outside the IPCC’s statements, ipso facto
they undermine the authority of science in the eyes of the public. This of
course reflects a very particular (purist) view of scientific knowledge which
scholars such as Bruno Latour have described as the ‘modernist illusion of
science.’5 And yet it is one that offers a wide variety of protagonists a useful
defence against cultural relativists.
Against consensus
But the argument against consensus as authoritative, at least in the context
of wicked problems like climate change and at least in the way in which the
IPCC has promoted it, seems to me to be compelling. Let me mention just
three aspects of this argument (although Beatty and Moore expound others
too).
First is an argument by analogy. Majority rule works very effectively in
maintaining authority in social institutions such as parliaments and the
courts, which involve voting MPs and juries. Consensus is not required
for a ruling or judgement to carry authority in wider public settings. And
whatever differences we might insist on between the nature of scientific
enquiry and political (or jury) debate, we must recognise that scientific
assessments such as the IPCC are established explicitly as social (i.e.,
deliberative) institutions which scrutinise evidence.6 There are many other
dimensions to the making of authoritative and trustworthy institutions
than unanimity amongst members; for example, fair and agreed procedure,
respect for dissent, acceptance of outcomes. Maybe the IPCC’s authority –
in the eyes of critics and publics, if not also in the eyes of politicians – would
therefore be enhanced if it acted on its own rules for minority reporting in
the Summary for Policymakers (which it never has).
Second, the requirement of consensus is pernicious – in order to protect the
authority of the group it encourages agreement in a group of experts where
there is none. Maybe the IPCC should more openly embrace the idea of expert
elicitation, or even expert voting as has been suggested by David Guston:
“A scientific body that does not partake in … a politics of transparent
social choice – one that hides both its substantive disagreements and its
disciplinary and sectoral interests beneath a cloak of consensus – is not
a fully democratic one.”7 For example, such an approach to disagreement
could usefully have been applied to the case of the sea-level rise controversy
in the IPCC’s 4th Assessment Report.8 It makes disagreements explicit and
better reflects the quasi-rationality of scientific deliberation. Another example
of how this might strengthen authority would be the case of the IUCN’s Polar
Bear Specialist Group and the embrace of expert elicitation.9
And, third, the presence of officially sanctioned – even welcomed! –
credible minority views, thereby revealing the extent of dissensus, actually
enhances the authority of science. It shows that it is ‘OK to disagree’ and
thus indicates that the deliberative procedures of a body like the IPCC
are fair and accommodating to the full range of accredited views. For
science to be authoritative, it should therefore welcome – indeed seek out
– its critics (see the attempts to do this, only partially successful, in the
case of the International Assessment of Agricultural Knowledge, Science
and Technology for Development).10 In the case of large international
assessments like the IPCC, and the newly constituted Intergovernmental
Platform for Biodiversity and Ecosystem Services, the process should not
just allow minority reporting in its rules of procedure, but ensure that
minority reporting is actively facilitated. As Dan Sarewitz has argued:
“Science would provide better value to politics if it articulated the
broadest set of plausible interpretations, options and perspectives,
imagined by the best experts, rather than forcing convergence to an
allegedly unified voice.”11
Climategate, consensus and the weakening of authority
The single-minded drive for an exclusionary consensus was the true tragedy
of Climategate. Not that the emails from the Climatic Research Unit (CRU)
revealed any fundamental faking of substantive data or fraudulent practice,
but that they showed a scientific culture which was closed to criticism and
which was resistant to the open sharing of data. When these practices
were publicly exposed, the tenacity of scientists’ defence of in-group/outgroup
boundaries paradoxically weakened the public authority of climate
science rather than strengthened it. The outcome was the exact opposite
of what climate scientists in CRU and elsewhere thought they were doing.
As a consequence, climate scientists handed the scientifically-credentialed
critics of climate science an easy target – exclusionary practices which run
counter to the nature of open debate and criticism. And this in turn handed
to politically-credentialed critics of mainstream climate policies a powerful
diversionary strategy. It opened the way to convert the agonistic spaces
of legitimate and healthy democratic argument about climate policies into
distracting – yet attention-grabbing and entertaining – arguments about the
authority of science.
The drive for consensus within the IPCC process, and its subsequent public
marketing, has becomes a source of scientific weakness rather than of
scientific strength in the turbulent social discourses on climate change.
By refusing to embrace and legitimise minority reporting, the IPCC has
opened the way for powerful counter rhetoric to emerge around the
idea of consensus, as illustrated by these two examples: Robert Carter’s
2010 book Climate: the counter consensus and Donna Laframboise’s
blog No frakking consensus, with the strapline: “Climate skepticism
is free speech. Alternative points-of-view deserve to be heard.”12
The relationship between scientific evidence and public policymaking is
sufficiently underdetermined to warrant large-scale assessments such as
the IPCC finding multiple ways of accommodating dissenting or minority
positions. They would be the more authoritative for doing so.
Mike Hulme is professor of climate change at the University of East
Anglia and author of ‘Why We Disagree About Climate Change’
(@3SResearchGroup)
Endnotes
1. IPCC Houghton, J.T., Jenkins,G.J. and Ephraums,J.J. (Eds.) (1990) ‘Climate change: the
IPCC scientific assessment.’ Cambridge: Cambridge University Press, (v).
2. Elster, J. (1986/1997) ‘The market and the forum: three varieties of political theory.’
p.3-34 in: Bohman, J. and Rehg,W. (Eds.)(1997) ‘Deliberative democracy.’ Cambridge
MA: MIT Press.
3. Beatty,J. and Moore,A. (2010) Should we aim for consensus? ‘Episteme’ 7(3), 198-214.
4. Houghton,J.T., Jenkins,G.J. and Ephraums,J.J. (Eds.) (1990) ‘Climate change: the IPCC
scientific assessment.’ Cambridge: Cambridge University Press. (v).
5. Skrydstrup,M. (2013) Tricked or troubled natures? How to make sense of
“climategate”. ‘Environmental Science and Policy.’ DOI 10.1016/j.envsci.2012.11.012 .
6. For example, Shapin,S. (2010) ‘Never pure: historical studies of science as if it was
produced by people with bodies, situated in time, space, culture and society, and
struggling for credibility and authority.’ Baltimore MA: The John Hopkins University
Press. 552pp.
7. Guston, D. (2006) On consensus and voting in science pp.378-405 in: Frickel,S. and
Moore,K. (Eds.)(2006) ‘The new political sociology of science.’ Madison WI:University
of Wisconsin Press. P.401
8. See Oppenheimer,M., O’Neill,B.C., Webster,M. and Agrawala,S. (2007) The limits
of consensus. ‘Science.’ 317, 1505-1506; O’Reilly,J., Oreskes,N. and Oppenheimer,M.
(2013) The rapid disintegration of projections: the West Antarctic Ice Sheet and
the Intergovernmental Panel on Climate Change. ‘Social Studies of Science.’ doi:
10.1177/0306312712448130.
9. For example, O’Neill,S.J., Osborn,T.J., Hulme,M., Lorenzoni,I. and Watkinson,A.R.
(2008) Using expert knowledge to assess uncertainties in future polar bear
populations under climate change. ‘The Journal of Applied Ecology.’ 45(6), 1649-1659.
10. Scoones, I. (2009) The politics of global assessments: the case of the International
Assessment of Agricultural Knowledge, Science and Technology for Development.
‘Journal of Peasant Studies.’ 36(3), 547-571.
11. Sarewitz, D. (2011) The voice of science: let’s agree to disagree. ‘Nature’ 478, 7.
12. Carter,R.M. (2010) ‘Climate: the counter-consensus – a scientist speaks.’ London:
Stacey International; Donna Laframboise’s blog ‘No frakking consensus’ http://
nofrakkingconsensus.blogspot.co.uk/
Tallbloke's Talkshop 
I find it rather surprising that Prof. Hulme talks about scientifically and politically credentialed individuals as if there was some kind of laying on of hands that endowed these people with supernatural insights. I am disappointed that he sees ‘science’ as a coherent entity rather than a random collection of disparate human activities each with its own arcane language, its own coterie of members and its own rites of passage. The new boy on the scene, climate ‘science’, born of political machination and attempting to thrive on tax payers’ money elicited by inducing fear of an uncertain future, is struggling now in the face of empirical data that, to naive uncredentialed onlookers, seem to falsify its fundamental thesis.
I find it rather quaint that Hulme seeks, by appealing to some populist notion of rule by the majority, to strengthen the authority of IPCC by acknowledging the existence of minority views, rather than to subject the whole enterprise to genuinely disinterested critical examination.
Let us apply Occam’s Razor – believing that human activity was creating global warming, politicians sought and received public support to fund ‘experts’ to discover how to avoid or at least ameliorate the effect of the coming disaster. The experts delivered their verdict and the politicians responded with a series of draconian measures that are resulting in the de-industrialisation of the West and the migration of capital to the East. In the event, global warming, as measured by the means that gave rise to the alarm, stopped and with that the flow of money into climate science is threatened. But the ‘experts’, instead of admitting that their thesis has been falsified, shift from ‘warming’ to ‘change’ and from temperature to a multitude of other causes for alarm and the politicians, knowing that their livelihood too is at stake, unwisely honour sunk costs and persist in enforcing their destructive policies.
Real Science would welcome the falsification of a thesis and politicians should be celebrating that the doom, if it ever existed, has been postponed indefinitely.
Surely that is the message Hulme should be deliveri
I do not know why anyone would want to quote Sir John Houghton. His book “The Physics of Atmospheres” shows he has no understanding of heat transfer and is incompetent or that he is trying to fool readers (or possibly a mix of both). He may be be guilty of plagiarism particularly section 1.4 Adiabatic lapse rate (which he mentions but does nothing with it and even ignoring it in a comment on the “greenhouse effect” on Venus) and section 9.1 The Reynolds Number (which is not further considered)
So an incompetent started the UN IPCC and it is still run by scientific incompetents who have a political agenda.
Has Prof Hulme something to do with UEA. or am I mixed up there?
“2,500+
scientific expert reviewers; 800+ contributing authors; and 450+
lead authors; from 130+ countries; 6 years work; 4 volumes; 1 error-prone distortion-filled report.”
There – I fixed it for you. Feynman answered the question of authority: If a hypothesis is wrong it’s wrong. I would add that once found wrong it cannot be made un-wrong and should be abandoned.
No, Cementafriend you are not mixed up. He is professor of climate change at the University of East Anglia – surprise?
Perhaps Hulme is saying that he is coming to realise they got it wrong and that they now need to begin to find ways to adopt a wider viewpoint into the consensus thus giving themselves the opportunity to metamorphose from global warming to climate change to global cooling.
It’s a form of exit strategy in case co2 doesn’t turn out to be a miracle gas, which any dispassionate observer will have already discovered.
Some will perhaps see this as a Trojan Horse disguised as an Olive Branch, but I think that any moves that help some of those scientists trapped by group think and fear of their jobs to articulate an opinion at odds with the consensus should be cautiously welcomed.
Prof. Hulme, if I may ask: You’ve chosen to post your commentary on the consensus here. Have you posted it to any of the- excuse my phrasing- Pro-AGW sites, or to newspapers such as the Guardian? And may I also ask, what response did you receive?
This is interesting.
Mike Hulme on “Post-Normal Science” from 2007.
http://www.guardian.co.uk/society/2007/mar/14/scienceofclimatechange.climatechange
The reason the IPCC adopts the consensus approach is simple. It works.
Have you ever seen such a case of special pleading as this nonsense about ‘post-normal science’?
Thank you catweazle666 – that patronising and ill-mannered attack on Singer et al tells us more about the ethos at UAE than any of the so-called investigations into climategate. I wonder how research scholars at UAE are treated if they even think about stepping out of line?
Yet on second thoughts; has he not laid a trap for himself? Surely this new kind of science, of which climate science is but one example, needs to be critically examined by his paymasters (us) before it can be accepted as sufficiently plausible to justify financial support and to be useful in guiding political policies? How can it be tested and how falsified?
Did the Minister who signed his paycheque know about this revelation?
Let him answer the call for transparency and justify this scientific revolution, this new paradigm!
This article is something of a mess. It asks the wrong question and makes the wrong assumptions. The problem of scientific argument is not one of authority, and for consensus to provide the basis for a discussion about authority means we have left the world of science. Mike Hulme doesn’t help us understand his position (which I cannot yet pin down fully) by using such slippery terms as ‘the authority of science’ in uncertain ways.
The whole scaffolding of majority-minority/consensus-dissensus as a basis for discussing any sort of scientific authority is misplaced. Having minority views is necessary but by no means satisfactory. Authority such as it is, a complex topic and I use the term only because it is used here, depends on method and process in science; viz. the openness of debate and the open acceptance of sound rules of enquiry and argument.
And more, good science, as part of this openness, questions assumptions/premises. This didn’t happen either with IPCC or with the Climategate actors. Also both IPCC and Climategaters ‘assumed’ that authority was a objective, and both came unstuck. The assumption of this essay is still that authority is the issue and that it is important. It isn’t and it isn’t.
The drive for consensus is one false conclusion of those who are deluded that authority is what its all about. Hulme still can’t let go of this pet idea and will therefore long wonder why the scientific debate has passed him by.
JPetch: Welcome, and thanks for your comment. I think the problem starts at the science-policy interface. You correctly point out that science isn’t, or at least shouldn’t be, about authority and consensus. But politics is all about authority mandated by the gaining of a majority. Politicians as the paymasters of institutional science have the senior role, and project the structure of their own Modus Operandi onto science governance.
This includes political tactics such as starving dissenting or otherwise potentially problematic organisations of funds. Example: Solar science suffered a catastrophic reduction in funding in the UK years ago. Funds were redirected into the expansion of atmospheric science departments.
“Not that the emails from the Climatic Research Unit (CRU) revealed any fundamental faking of substantive data or fraudulent practice … ”
So evidence of the practice of grafting on non-complementary temperature records, cherry-picking data, etc., is acceptable scientific practice ? Here, pull my finger !
Tallbloke: Thank you for your rely and, if respectfully I may disagree, the problem doesn’t start at the science-policy interface. The problem of authority is deeper than that and exists in politics too.
There is a psychological impulse to need authority and to want to impose authority. Its a permanent battle ground in science and in politics. I think it is a response to the problem people have in dealing with uncertainty. And in both domains authority is rarely a lasting solution to situations and problems in which there is uncertainty .
In government it is manifest in the need to plan and control. Although I agree that politics is ‘about’ authority I subscribe to the view, along with many others, that is should not be ‘for’ authority. Authority should be used to achieve goals on behalf of those who have mandated its use and the lessons of history tell us that use of authority is best minimised. This seemingly abstract issue is brought in to concrete focus when we compare the current authoritarian approach of government to dealing with perceived problems of future climates as opposed, for instance, to the policies advanced by Lord Lawson and others of adaptation rather than diktat.
In science the problem of uncertainty is best dealt with by openness and by rigour of method rather than authority; in politics by openness and flexibility. But in both cases the real solution lies in developing the mindset of being comfortable with uncertainty. As Popper says of science, “….the greatest error is the quest for certainty.” It applies to politics too.
What is discomforting about Mike Hulme’s essay is the assumption of the need for authority on both sides of the science-politics divide.
Asking bankers from HSBC (cartel money laundering division) about how they should have listened to dissenting views & should not be prosecuted, would probably come up a Hulme like response. The same could be said regarding politicians during the expenses scandal. Again and again the very people responsible for the mess propose solutions to the problems they created-insiders telling us yes they have been a wee bit naughty but it’s all behind them now (as highlighted by streetcred above). In hindsight accepting a few dissenting opinions will not give CRU credibilty. All we will probably get is a shuffle of the pack, a fresh lick of paint and an ‘Under New Management’ sign. Far too little, far too late.
JPetch: Great response, thanks. I agree with it too. 🙂
Mike Hulme nearly says that the strength of the ‘consensus’ argument is the faith that if a field of inquiry is a Science, then its results are certain. I now think that the real radical thrust of Post-Normal science is at the beginning of the motto: “Facts uncertain….”. How can there be uncertain facts, or worse, false facts? That seems logically impossible, as well as being subversive.
For some perspective on Climate Science, where would we put it on a spectrum that includes Nutrition, Economics and Psychiatry? Each of those sciences includes a lot of theory and empirical data; and they each have importance for policy in all sorts of ways. And yet they are each recognised as problematic, and not at all free of uncertainties. Would the public be more trusting if in those other sciences consensus pronouncements were the norm, and critics were deemed to be unworthy?
Excellent context widening question Jerry, but I see a snare. The three ‘sciences’ you’ve flagged up are related to the sphere of human social activity, and the inner workings of human minds and bodies. As Sir Brian Hoskins’ interlocutor on a recent radio 4 programme said, “Lock two economists in a room for an hour, and you’ll get three theories of economics”. Psychiatrists fall into various camps harking back to Jung, Freud and Skinner, and Nutritionists frequently reverse previous advice about salt, butter, fatty meat and fish as fashions and the food industry dictate. ‘Climate science’ narrowly defined, is a geoscience, with a tiny bit of astrophysics tacked in order to dismiss the possibility of significant solar influence on Earth’s climate systems. These are physical sciences, and only one reasonably long lasting paradigm at a time is allowed in each, otherwise the world goes all wobbly and the heavens dissolve before our eyes.
All the human related parts of climate science are contracted out to ‘impact studies’ and the like. In fact, it is these extraneous bits of climate science Hulme is most concerned about. He is a policy man at heart I think. But he does recognise that before policy development and implementation can proceed to spend billions of pounds of taxpayers money, it needs to be underpinned by ‘the physical scientific basis’ of Anthropogenic Global Warming theory. So Hulme needs there to be an acceptance of ‘the science’ before he can proceed. He accepts it, and the fact others don’t is, as he sees it, a problem to be fixed, rather than a healthy part of an ongoing scientific process. he proposes to fix the problem by allowing a ‘minority report’ to be included in the IPCC report, which can then be safely ignored, along with the latest rantings of the dissenters, because ‘they had their say’.
The poor weary public puts up with the changing policies in the ‘social sciences’ because, by and large, the practitioners they interact with directly carry on doing what they do regardless of the rarified academic theorising. However with climate science, the public looks out of the window at the weather, and stares in disbelief at last winter’s gas bill, and hears Ed Davey on the today programme telling them that in order to relieve fuel poverty, his policies will raise bills another 33% by 2020 on top of the doubling since 2005. And this is because 97% of scientists agree that their funding agencies prefer it that way.
Very well put – thanks!
“peer review has helped ensure a high degree of consensus”. Yep, it’s called “gatekeeping”.