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Teaching and Learning Resource (TLR)
1. Title
Environmental Risk and the Precautionary Principle
2. Keywords
Scientific uncertainty; environmental risk; precautionary principle.
3. Introduction
In environmental risk management, the principle of 'precaution' is broadly understood to mean 'erring on the side of caution'. It reflects the view that action to forestall possible environmental harm or threats to human health and safety may well be justified, even where conclusive scientific evidence of such adverse consequences cannot be produced. Such a view follows from the belief that 'conclusive evidence' is particularly hard to find in the uncertain and contested field of environmental science, and especially so within the timescales that may be necessary if ecological disasters and human tragedies are to be averted.
In effect, the precautionary principle requires a reversal of the 'burden of proof', vis-à-vis that which conventionally operates in science. Advocates argue that responsibility should reside with those wishing to undertake any action that could conceivably cause harm - either to demonstrate its harmlessness, beyond reasonable doubt, or to abstain from that action: the burden should not, in their view, fall on those wishing to protect the environment and/or human health to demonstrate the harmful nature of such an action.
It is commonly asserted that the principle of 'precaution' differs from that of 'prevention', insofar as the latter characterises action taken to avoid certain harm to the environment or to human health and safety. However, precisely because environmental scientific knowledge 'claims' are so frequently subject to uncertainty and contestation, consensus about which actions should be considered preventive - and which are 'merely' precautionary - is itself something of a rarity. This, in turn, is but one aspect of a broader debate, about which acts of environmental protection are necessary, and which are unnecessary - regardless of whether they be undertaken in the name of 'precaution' or 'prevention'. In general, the field of environmental risk is currently subject to intense scientific and political debate; it attracts enormous attention from the mass media, environmental pressure groups, the business community and politicians. In particular, the precautionary principle has become something of a cause célèbre amongst its advocates - and, conversely, a bête noire for its opponents - since it embodies many of the wider points of opposition which characterise this highly contested terrain.
4. Aim
This TLR aims to provide students with an interdisciplinary and critical introduction to the field of environmental risk in general, and to the 'precautionary principle' in particular.
5. Learning outcomes
Students who have engaged successfully with this TLR will:
This TLR requires an ability to engage with ideas pertaining to:
These ideas are introduced, variously in the accompanying Appendix (below) and in related TLRs (see below, Links with other TLRs). Nonetheless, students with little previous experience in these areas will find this a demanding exercise. More generally, those whose prior educational experiences have explicitly or implicitly encouraged the concretisation of an unproblematic view of environmental knowledge (as 'truth' or 'fact') will be particularly challenged by this TLR.
Optimum benefit will probably be derived from this TLR if students are given sufficient time, opportunity and incentive to explore it in depth. The following sequence of activities - involving a combination of private study, interactive class-based learning, and assessment - is therefore proposed:
I Introductory briefing
This might - but need not - involve an element of lecturing on the topic itself. It should, however, include an introduction to the learning outcomes, to the printed materials and other recommended sources, to the learning tasks, and to the assessment requirements. It should also include references to relevant learning activities previously undertaken.
The class should, at this stage, be divided into eight approximately equal-sized groups, ideally consisting of 3-4 students. (In the event of there being fewer than 16 students, the class could be divided into a lesser number of groups.) All groups should, at this stage, be briefed to research all aspects of the discussion question given below.
These activities are preferably to be undertaken after the printed materials have been read (ideally during students' private study time). Approximately 30-40 minutes (including question and answer time) are probably needed for an effective briefing.
II Private study
Students should, if possible, be allowed at least three weeks to make notes from the printed materials, and to undertake further research using the recommended sources, in preparation for the main class-based learning activity. Private study should be organised on a group basis, such that each group is prepared to lead a class discussion on any one (or more, in the event of there being fewer than eight groups) aspect(s) of the following discussion question:
Explain (with examples) the variety of ways in which the precautionary principle has been interpreted - for example by prominent lobbyists (e.g. Greenpeace) and commentators, national governments, supra-national authorities (e.g. the EU) and/or inter-governmental bodies (e.g. UNEP, signatories to an international agreement) - especially in terms of:
Where possible, indicate which are the 'stronger' and 'weaker' interpretations, and the underlying philosophical commitments which apply in each case.
* These questions could be omitted if a more curtailed discussion is considered appropriate
III Class-based activity
Each student group should be asked to lead the class discussion on any one (or more) aspect(s) of the discussion question. This can probably be most effectively achieved if each group nominates one member to make a short presentation (5-6 minutes), to be followed by class comments and questions to the group as a whole.
At least 75 minutes could be profitably assigned to this activity, but (with careful management and the omission of some questions) it could probably be completed within 60 minutes.
IV Assessment
Students might be asked to submit an individual essay of 2000-2500 words, along the following lines:
With particular reference to environmental risk and the precautionary principle, critically appraise:
In order to achieve the learning outcomes and satisfy the assessment requirements, you will need to use the printed materials provided and other recommended sources to complete the following tasks:
1. Undertake group research on the following question:
Where possible, indicate which are the 'stronger' and 'weaker' interpretations, and the underlying philosophical commitments which apply in each case.
2. Specifically, prepare your group to participate in a class discussion on all aspects of this question, and to lead on any one aspect of it (to be assigned at the start of the class). For this latter purpose you should nominate a spokesperson to each aspect of the question, and brief that person to make a short presentation (5-6 minutes). Each presentation will be followed by class comments and questions to the group as a whole.
3. Submit an individual essay of 2000-2500 words, along the following lines:
9. Stimulus Material
See Recommended reading and Appendix, below.
10. Degree stage
For reason of the Pre-requisites stated above, this TLR is likely to be most appropriately used with students who are operating at academic level 3 (or who are accustomed to the interdisciplinary and 'critical' approach adopted here).
11. Resource requirements
The class-based elements of this TLR can operate in any suitably-sized teaching room that is appropriate for interactive work. An overhead projector (with transparencies and marker pens) and/or flipchart (with marker pens) may be useful.
12. Preparation
No specific preparation is required.
No TLR systematically develops the pre-requisite understandings for this exercise, though the following may provide useful preparation:
The following TLRs are also linked, albeit in a 'horizontal' (as opposed to 'vertical') relationship:
More generally, the aims and/or learning outcomes of this TLR are related to those of other TLRs listed in the following 'thematic clusters':
14. Follow-up activities
No specific follow-up activities are proposed, though the range of possible topics suggested for assessment purposes (see above, How to use TLR and Instructions to students) may also afford some opportunities for follow-up work.
The accompanying Appendix (below) endeavours to provide a systematic introduction to those academic debates, about scientific uncertainty and environmental risk, which are relevant to an understanding of the precautionary principle. It does not, however, deal at length with the differences in interpretation of this principle, which provide a focus for the learning activities proposed here. For this purpose, students may usefully consult:
Canadian Environmental Protection Agency website
Royal Commission on Environmental Pollution website
For wider reading (e.g. to support the proposed assessment task, and for follow-up to the TLR), students might consult other sources cited in the Appendix. In addition, they may find it useful to consult some standard sources on environmental risk, including:
Adams, J (1995) Risk. UCL Press
Krimsky, S and Golding, D, eds (1992) Social Theories of Risk. Greenwood
Beck, U (1992) Risk Society: Towards a New Modernity. Sage
Beck, U (1995) Ecological Politics in an Age of Risk. Polity Press
Lash, S, Szerszinski, B and Wynne, B, eds (1996) Risk, Environment and Modernity: Towards a New Ecology. Sage
Lofstedt, R and Frewer, L, eds (1998) The Earthscan Reader in Risk and Modern Society. Earthscan
16. Users' comments
“The aims and learning outcomes were very appropriate for this [3rd undergraduate] level of study.”
"Although we used this material at level two because it fitted most comfortably with a level two unit, it may be more appropriate for level three students.”
“The notes provided … were extremely useful and provided the students with what seems to be quality material from several well-known sources.”
“The materials provided offered a useful starting point for the students. However few made use of the resources recommended in the materials. This was partly due to problems of access … and partly because of the issue specific nature of many of the assignments submitted. There was a tendency … to rely heavily on web sites and newspapers … rather than consulting more academic sources.”
“The activities the students undertook in presenting their discussions and debating the issues were appropriate.”
“The class discussion would seem to be an effective and appropriate approach to achieving the learning outcomes for this TLR. It relies heavily however, on each group undertaking the necessary research and engaging fully in the discussion.”
“The students apparently at the end of the session had quite a detailed understanding of the ways in which ‘uncertainty’ can arise in the process of scientific claims-making. They could appreciate that science cannot always give the answers and that even probability is not the holy-grail they had been led to believe from their statistics classes. They were able to appreciate that differing views of scientific uncertainty and environmental risk arise from differing political and philosophical commitments and backgrounds… and even for science students appreciate the value of an interdisciplinary approach to environmental risk.”
“[The TLR] provided a challenging assignment that the better students engaged with well. However many of the cohort failed to engage fully with the aim as presented in the assignment.”
“How to encourage students to engage in [active learning] sessions of this nature is an on going problem … The students themselves have suggested that assessment of the presentations may have encouraged better attendance.”
“This TLR provides an excellent introduction to environmental risk and the precautionary principle. With minor adaptations it can be used to encourage either broad consideration of the topic or can be used to focus on a particular issue of current concern.”
“Gives the lecturer a topic that can almost be used off the shelf.”
“We intend to use a longer lecture session in future so as not to rely completely on the class discussion session to raise and address issues.”
“It has helped my understanding of the precautionary principle and scientific truth.”
APPENDIX:
Scientific Uncertainty, Environmental Risk and the 'Precautionary Principle'
I. Scientific Uncertainty and Environmental Risk Assessment: The Mainstream View and its Critics
The field of environmental risk deals with threats posed to human health and safety and to ecosystems, though in practice - at least, until quite recently - the former have been dominant in the academic literature and in professional applications. Similarly, whilst environmental threats are potentially associated with adverse anthropogenic and natural events, the former have attracted considerably more attention. Hence the archetypal environmental risk is that posed to human health and safety, and by 'technological' hazards such as industrial installations or polluted environments. Regulatory and other legal pressures, including the threat of civil liability, have been a major driving force behind these developments - as, indeed, they have been also in the more recent (and partial) refocusing of risk-related interest on ecological threats, such as loss of biodiversity.
Not surprisingly, perhaps, given these close industrial associations, the paramount intellectual influence on studies of environmental risk has been that of 'scientific and technical rationality'. From this perspective, science offers the only reliable basis for assessing risks; and technology holds out the best hope of avoiding - or, at least, minimising - most such risks. By these means, potentially damaging human (e.g. industrial) activities can be accommodated.
However proponents of this view acknowledge that the assessment and management of environmental risk is, by definition, subject to scientific uncertainty, associated variously with:
Gerrard (1995: 306) suggests 5 different 'data quality' levels on which risk assessments are in practice made, from:
He notes that:
In common with many advocates of scientific risk assessment, Gerrard (1995: 306) expresses the hope that "as databases become larger and processes better understood it will be possible to undertake risk assessments more reliably." Others are more sceptical. For example, MacGarvin's (1994) review of attempts to establish safe pollution limits for the North Sea - which would thereby provide, not only for human health protection (e.g. in relation to contamination of fish stocks), but also for protection of the marine ecosystem as a whole - notes that "research is still turning up unexpected and disturbing results, despite the North Sea being amongst the most intensively studied marine area [sic] in the world." (73) Commenting on the 'failure' of marine biology and ecology to match their own practitioners' and others' expectations, in terms of explanatory and predictive models, he draws particular attention to:
Other authors, including O'Riordan (see in particular O'Riordan, 1995; O'Riordan and Cameron, 1994; O'Riordan and Jordan, 1995) and Wynne (see especially Wynne, 1992; Wynne and Mayer, 1993 ) are equally sceptical about the potential of science to set safe limits for anthropogenic environmental modifications. For example, O'Riordan (1995: 8) notes that:
He concludes:
Many philosophers and sociologists of science would probably consider these 'stronger' arguments to be consistent with their wider view of the provisionality, selectivity and value-laden tendencies of scientific knowledge in general (see, for example, Chalmers, 1988; Kuhn, 1962 and 1963). According to Yearley (1991) and others, however, these problems tend to be particularly acute in the case of environmental science, and for three main reasons:
Wynne and Mayer (1993) clearly have this critique of science in mind when they write:
They claim that, in the context of debates about safe limits for industrial discharges, this approach "reduces the recognised possible environmental effects to a few observable end results such as lethal dose, or induction of disease in fish, and then asks whether cause-and-effect chains can be observed between these selected effects and the discharge of given chemicals." (33) Such an approach, they continue, is unlikely "to accept multiple interactions and composite variables such as the health of an organism's immune system, stress and disease, which are intrinsically less precise and reductionist." (34) In general this approach creates a misleading impression of scientific precision in environmental policy-making:
These 'stronger' and 'weaker' accounts of scientific uncertainty also reflect wider differences of environmental philosophy, which are manifested in:
II. Scientific Uncertainty and Environmental Risk Management: The Policy Debate
Advocates of scientific risk assessment do not deny the relevance of philosophy and the social sciences (including economics, sociology and psychology) to the field of environmental risk - but seek to confine their influence to the spheres of policy and management. Hence, from this perspective, sociology and psychology can assist in revealing and managing public opinion; economics offers a basis for weighing the costs and benefits associated with (for example) proposed risk reduction (or, for that matter, proposed risk accommodation) measures; and philosophy can inform judgements about 'fairness' in the social allocation of risk. In all of these respects, however, scientific knowledge per se is effectively 'insulated' from the encroachment of philosophy and the social sciences - and vice-versa*.
As we have seen, critics of scientific risk assessment reject this 'socially insulated' view of science. They also take issue with the supposed neutrality of cost-benefit analysis (CBA), which has formed the corner-stone of conventional approaches to risk management - on the grounds that neither the scientific assessment of risk, nor the economic valuation of costs and benefits associated with alternative management strategies (to be implemented once the risks themselves are known scientifically), are value-free activities. O'Riordan and Jordan (1995) note that CBA "assumes not only that some actual or computational value can be placed on the cost-benefit stream, but that the future flow of gains and losses should be equated at the point of analysis through discounting to present values." (201) They argue, however, that in many cases the benefit stream:
Hence the critique of CBA combines with that of scientific risk assessment (and with the associated philosophical dispositions noted above) to give an essentially sceptical view of the protection afforded against environmental risk, by these conventional approaches. These doubts have led, in turn, to the development of an alternative - precautionary - approach to risk management. According to O'Riordan and Jordan (1995), again, the 'precautionary principle' charges decision-makers with responsibility to:
Leaving aside for a moment any points of contention concerning this particular formulation, we can say that - in general - advocates of the precautionary principle are calling for a reversal of the 'burden of proof', vis-à-vis that which conventionally operates in science. In scientific hypothesis testing, the plausibility of a postulated cause-effect relationship is normally discounted unless there is a 95 per cent (or greater) probability that two variables are correlated. When applied to investigations of the possible environmental harm which might follow from a given action (e.g. an emission or discharge), however, this convention introduces the (potentially catastrophic) possibility of so-called 'Type II statistical errors': that is, acceptance of the 'no environmental harm' hypothesis, when more rigorous testing (especially use of larger samples and/or more appropriate parameters) would produce the 95 per cent confidence level necessary for rejection of this 'null hypothesis' - and acceptance of the alternative ('environmental harm') hypothesis. Hence precautionary principle advocates argue that responsibility should reside with those wishing to undertake any action which could conceivably cause harm - either to demonstrate its harmlessness, beyond reasonable doubt, or to abstain from that action: the burden should not, in their view, fall on those wishing to protect the environment and/or human health to demonstrate the harmful nature of such an action - since conclusive scientific evidence often cannot be produced, particularly within the relevant timescale for preventive action.
The precautionary principle is now widely recognised by environmental scientists, lobbyists and politicians - but not universally so. For example, Milne (1993) has argued that abandoning the 'no cause-effect' presumption of the null hypothesis amounts to a rejection of science itself, in favour of moral philosophy - and is particularly scathing of those whose 'impossible' demands are motivated by a wish "to put manufacturing industry out of business" (37):
Milne is equally dismissive of the precautionary principle's legal merits, attributing to academic lawyer Daniel Bodansky the view that it "is uselessly vague: it cannot measure how much caution is required, or how much harm may be done" (ibid). Likewise Smith (1995), writing in the pages of Economic Affairs (journal of the Institute of Economic Affairs), argues that:
For these and other authors who write from an 'industry' perspective, acknowledgement of environmental risk is largely confined to cases of high level (especially accidental) exposure. For example, Le Fanu (1995), also writing in Economic Affairs, rejects the findings of a Medical Research Council-commissioned report into the threats to male fertility posed by xenoestrogens, on the grounds that "the amount of [naturally occurring] oestrogen we consume in food is 4 x 107 higher than that from xenoestrogens" (16). Milne (1993) uses similar reasoning to defend the use of copper as a pesticide in antifouling paints and other products:
The general arguments, with which these and other cases of alleged harm caused by 'low-level exposure' are dismissed, are biological. According to Le Fanu (1995), again:
He continues:
Most of the scientific arguments advanced here are almost certainly not supported by the weight of expert opinion**. For example, an important distinction is commonly made - but apparently overlooked by Le Fanu - between naturally occurring oestrogen and industrially produced xenoestrogens, which (in the latter case) are not necessarily broken down or processed by the body. Similarly Milne's argument about global burdens of copper would be widely dismissed as irrelevant to concerns about locally high concentrations, and their possible effects on marine life, especially in the vicinity of busy marinas. Wider scientific arguments, about humanity's resilience in the face of environmental threats, would be seen by many as wholly unsubstantiated in circumstances where those threats are quantitatively and qualitatively without precedent.
However, while the science of those who oppose the precautionary principle appears shaky in relation to the weight of current expert opinion, the philosophical arguments are less readily dismissed. First, Milne's proposition, that abandoning the 'no cause-effect' presumption of the null hypothesis amounts to a rejection of science itself, in favour of moral philosophy, has some plausibility - but only insofar as one overlooks those value judgements which underlie the conventional approach itself (since the currently-accepted conventions of hypothesis testing, including the 'no cause-effect' presumption of the null hypothesis and the customary use of 0.05 and 0.01 rejection levels, are themselves clearly not products of empirical science). Second, while his claim that "[t]here can be no absolute proof of 'safety' or 'harmlessness' even if we want there to be one" (emphasis added) is not widely disputed (since, while Type II errors can be reduced by progressively more rigorous testing, they can never be eliminated entirely), the criticism applies only to those few advocates of the precautionary principle who are unwilling to accept 'elimination of reasonable doubt' as their 'compromise' criterion for demonstrating harmlessness. Finally Smith's argument - that continuing 'progress' provides the surest basis for responding to environmental threats - goes to the heart of the debate between technological optimists and sceptics/pessimists, and is clearly not the view of an isolated minority. However the fundamental objections to this argument, as expressed here, would be:
Amongst those who acknowledge the desirability of some kind of precautionary environmental action, then, there is considerable variability of approach, especially in terms of :
These differences of interpretation are most systematically documented in Cameron (1994) and Haigh (1994), along with the CEPA website (see below), and are illustrated by the examples in Box 1. They also provide a focus for the learning and teaching activities associated with this TLR.
** I am grateful to Dr Mark Huxham (Department of Biological Sciences, Napier University, Edinburgh) for his assistance with some of the points made here.
Box 1 The Precautionary Principle: Some Prominent Interpretations
| "[The participants] accept the principle of safeguarding the
marine ecosystem of the North Sea by reducing pollution emissions of
substances that are persistent, toxic and liable to bioaccumulate at
source, by use of the best available technology and other appropriate
measures. This applies especially when there is reason to assume that
certain damage or other harmful effects on the living resources of the
sea are likely to be caused by such substances, even when there is no
scientific evidence to prove a causal link between emissions and effects" Ministerial Declaration of the Second Conference on the Protection of the North Sea, 1987 |
| "... Determined to protect the ozone layer by taking
precautionary measures to control equitably total global emissions of
substances that deplete it, with the ultimate objective of their
elimination on the basis of developments in scientific knowledge, taking
into account technical and economic considerations and bearing in mind
the developmental needs of developing countries" Montreal Protocol on Substances That Deplete the Ozone Layer (Preamble, Para.6), as amended in 1990 |
| "... AGREES that ... the Contracting Parties shall be guided
by a precautionary approach to environmental protection whereby
appropriate preventive measures are taken when there is reason to
believe that substances or energy introduced in the marine environment
are likely to cause harm even when there is no conclusive evidence to
prove a causal relation between inputs and their effects" London Dumping Convention (Resolution LDC 44/14), 1972, as amended in 1991 |
| "In order to protect the environment, the precautionary
approach shall be widely applied by States according to their
capabilities. Where there are threats of serious or irreversible damage,
lack of full scientific certainty shall not be used as a reason for
postponing cost-effective measures to prevent environmental degradation" UNCED Declaration (Principle 15), Rio de Janeiro, 1992 |
| "The precautionary principle, by virtue of which preventive
measures are to be taken when there are reasonable grounds for concern
that substances or energy introduced, directly or indirectly, into the
marine environment may bring about hazards to human health, harm living
resources and marine ecosystems, damage amenities or interfere with
other legitimate uses of the sea, even when there is no conclusive
evidence of a causal relationship between the inputs and the effects" Convention for the Protection of the Marine Environment of the North-East Atlantic (Article 2 (2) (a)), 1992 |
| "The Parties should take precautionary measures to anticipate,
prevent or minimise the causes of climate change and mitigate its
adverse effects. Where there are threats of serious or irreversible
damage, lack of full scientific certainty should not be used as a reason
for postponing such measures, taking into account that policies and
measures to deal with climate change should be cost effective so as to
ensure global benefits at the lowest possible cost" UN Framework Convention on Climate Change (Article 3 (3)), 1992 |
| "Where appropriate (for example, where there is uncertainty
combined with the possibility of the irreversible loss of valued
resources) actions should be based on the so-called 'precautionary
principle' if the likely balance of costs and benefits justifies it.
Even then the action taken should be in proportion to the risk" UK Strategy for Sustainable Development - DoE Consultation Paper, 1993 |
| "A simpler, more flexible and more applicable definition
states that 'No wastes should be discharged into the sea unless it can
be shown that they are harmless'" Johnston, P and Simmonds, M, 'Precautionary principle' (letter), Marine Pollution Bulletin, 21(8), p.402 |
| "The precautionary principle states that, in the case of
marine pollution, no activities should be permitted unless there is a
clear understanding of the likely consequences of those activities for
the marine environment" Greenpeace Website |
Works Cited and Consulted
Printed Sources
Cameron, J (1994) 'The status of the precautionary principle in international law' In T O'Riordan and J Cameron, eds Interpreting the Precautionary Principle, pages 262-89. Earthscan
Chalmers, A (1988) What is this Thing called Science? Open University Press
Gerrard, S (1995) 'Environmental risk management' In T O'Riordan, ed Environmental Science for Environmental Management, pages 296-316. Longman
Haigh, N (1994) 'The introduction of the precautionary principle into the UK' In T O'Riordan and J Cameron, eds Interpreting the Precautionary Principle, pages 229-51. Earthscan
Johnston, P and Simmonds, M (1990) 'Precautionary principle' (letter) Marine Pollution Bulletin, 21(8), page 402
Kuhn, T (1962) The Structure of Scientific Revolutions. University of Chicago Press
Kuhn, T (1963) 'Scientific paradigms' In B Barnes, ed The Sociology of Science, pages 80-103. Penguin
Le Fanu, J (1995) 'Can we determine what level of environmental toxins presents a serious risk?', Economic Affairs, 16(1), pages 15-18
MacGarvin, M (1994) 'Precaution, science and the sin of hubris' In T O'Riordan and J Cameron, eds Interpreting the Precautionary Principle, pages 69-101. Earthscan
Milne, A (1993) 'The perils of green pessimism', New Scientist, 12 June, pages 31-7
O'Riordan, T (1995) 'Environmental science on the move' In T O'Riordan, ed Environmental Science for Environmental Management, pages 1-11. Longman
O'Riordan, T and Cameron, J (1994) 'The history and contemporary significance of the precautionary principle' In T O'Riordan and J Cameron, eds Interpreting the Precautionary Principle, pages 12-30. Earthscan
O'Riordan, T and Jordan, A (1995) 'The precautionary principle in contemporary environmental politics', Environmental Values, 4(3), pages 191-212
Smith, F (1995) 'Assessing the political approach to risk management', Economic Affairs, 16(1), pages 11-14
Wynne, B (1992) 'Uncertainty and environmental learning: reconceiving science in the preventive paradigm', Global Environmental Change, 2, pages 111-27
Wynne, B and Mayer, S (1993) 'How science fails the environment', New Scientist, 5 June, pages 33-5
Yearley, S (1991) The Green Case, chapters 2 and 3. (Routledge)
Websites