Peer Reviewed: Life-cycle assessment and the precautionary principle

Current methods for life-cycle assessment are only partially in line with the precautionary ... Journal of Environmental Management 2009 90 (12), 3690...
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Life-Cycle Assessment and the

Precautionary Principle Current methods for life-cycle assessment are only partially in line with the precautionary principle. ARNOLD TUKKER

any believe that mainstream life-cycle assessment (LCA) fits perfectly well with the precautionary approach toward environmental policy, but is that really true? LCA, in general, calculates the potential effects of all emissions from a product system, regardless of whether such emissions result in concentrations under an effect threshold or not (1, 2). This is clearly a precautionary attitude. On the other hand, current methods for LCA are heavily oriented toward linking some emissions (or other interventions in the environment) with a potential effect using quantitative calculation models. This, by implication, assumes significant insight into these links. The precautionary principle, however, stresses the need to take preventive action before conclusive scientific evidence about such links is available. This viewpoint looks at whether LCA and the precautionary principle easily match. In exploring this question, a rigorous distinction between sciencebased analysis, as found in LCA, and the political decision-making process is deliberately avoided. Modern policy science finds that the boundary between these two approaches is not as sharp as it seems. Scientific tools often contain more fundamental value choices than may be apparent at first,

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and tools often have a more prescriptive role in decision making than is often thought (3–5). Hence, the question of how LCA relates to the precautionary principle is a valid and important one.

A closer look at LCA The methodology of LCA was developed to evaluate and compare the environmental impacts from the production, use, and waste management of certain products, such as the bumper on a car or disposable versus reusable diapers. Expert scientific groups under the umbrella of organizations such as the Society of Environmental Toxicology and Chemistry and international standardization bodies like the International Organization for Standardization (ISO) have developed a commonly applied framework for LCA. This structure can be categorized as follows (6–10): Goal and scope definition. In this phase, the study’s purpose and scope are defined along with a quality assurance scheme for the results. A functional unit is defined so that products can be compared on the basis of the functions they fulfill rather than their quantitative amount. For example, a milk bottle may be collected, cleaned, and reused 15 times and thus fulfill the same function as 15 milk packs. FEBRUARY 1, 2002 / ENVIRONMENTAL SCIENCE & TECHNOLOGY I 71 A

The precautionary principle Inventory. All process chains for the manufacturing, use, and waste management of the product funcThe precautionary principle has been adopted as a tion are defined. For each process in this chain, the guideline in many environmental documents. The relevant environmental interventions, such as air and principle is commonly held to have its roots in the water emissions or the extraction of primary reGerman environmental policy of Vorsorgeprincip, sources, are inventoried. These interventions are which was first formulated in 1976. Since then, nuadded by type and totaled for all the processes. The merous international forums have adopted the prinresulting inventory table lists all the environmental inciple as a basis for policy making (1, 2). terventions associated with the product’s function. A However, it was the 1992 U.N. Conference on typical inventory table can contain more than 100 inEnvironment and Development in Rio de Janeiro, terventions, such as the total emissions of lead or SO2 Brazil, that marked the broad acceptance of this prininto the air and water. ciple. According to the conference’s Agenda 21: “In Impact assessment. This step aggregates the inorder to protect the environment, the precautionary formation obtained from the inventory. First, impact approach shall be widely applied by States according categories are classified, usually in reference to a to their capabilities. Where there are threats of sericommon mechanism of environmental threat—for ous or irreversible damage, lack of full scientific cerexample, global warming, acidification, or ozone detainty shall not be used as a reason for postponing pletion. Using mathematical models that reflect the cost-effective measures to prevent environmental relationship between the intervention and impact, degradation” (13). the inventoried environmental interventions are Other treaties include similar or even more strongtranslated into scores for each impact category. For ly formulated statements. For instance, Freestone and example, the scores under the theme of human toxHey (1) describe formulations such as “must not wait icity are often calculated with the help of an adaptfor proof of harmful effects” (from the 1984 Bremen ed version of the European Union System for declaration on the Protection of the North Sea) and Evaluation of Substances (EUSES), which is basical“when there is reason to assume that certain damage ly a multimedia model. Given the amount of a speor harmful effects . . . are likely to be caused . . ., [councific emitted substance, EUSES calculates the tries must] avoid potentially damaging effects . . . even compound’s (potential) environmental concentration when there is no scientific evidence to prove a causal and (potential) daily intake and expresses this as a link” (from the 1989/1 Recommendation of Parcom). fraction of the tolerable daily intake. (11). These scores Compared to Agenda 21, these older formulations put are the impact profile of a product’s functional unit. less emphasis on “cost-effectiveness”, the “seriousInterpretation. In this step, all of the information ness of damage”, or the “capabilities of taking meagathered during the inventory and impact assessment sures”. is interpreted in relation to the study’s defined goal Probably one of the strongest formulations of the and scope. In principle, the impact categories could precautionary principle comes from the scientists be aggregated, providing one score for the product’s who published the 1998 Wingspread statement (14). environmental impact, but the ISO standard does not Among other items, the one-page statement says, allow such a “weighting” in comparative LCAs dis“When an activity raises threats of harm to human closed to the public (9). health or the environment, precautionary measures Two elements of this approach stand out. First, should be taken even if some cause-and-effect relabecause all of the environmental interventions for tions are not fully established scientifically. In this the different processes in the system are added tocontext the proponent of an activity, rather than the getherregardless of location or timeand then public, should bear the burden of proof. The process translated into impact category scores, the question of applying the precautionary principle must be open, of whether an emission leads to local contamination informed, and democratic, and it must include pois not of concern. Mainstream LCA simply provides tentially affected parties. It must also involve an exinsight into potential time- and location-indepenamination of the full range of alternatives, including dent effects related to a product function. Thus, LCA no action” (14). follows a philosophy of “less-is-better” rather than Regardless of the wording, a minimum of four el“only-above-threshold”. ements forms the principle’s key issues (1, 2, 15). First, Second, the LCA community prefers using matheecological space must be safeguarded so that the matical equations to calculate the quantitative, gener“margins of tolerance” are not even approached. This ic contributions of interventions to endpoints truly at concept implies a shift away from policies based on the end of the emissions–effect chain. For example, dis“dilute and disperse” (the assimilative capacity apability-adjusted life years lostan indicator expressing proach). Next, there must be an element of preventhe effect of a toxic emistive anticipation, which sion in terms of its negameans a willingness to Mainstream LCA simply tive effect on the number take action in advance of provides insight into of years that can be lived in scientific proof of danger. good health for a general The third element is propotential time- and locationpopulation are often portionality of response in suggested as the yardstick independent effects related to relation to the margins of for the human toxicity imerror and uncertaina product function. pact category (12). ty/ignorance. Finally, the 72 A I ENVIRONMENTAL SCIENCE & TECHNOLOGY / FEBRUARY 1, 2002

burden of proof is reoriented approach is ap“When an activity raises versed: Those who proplied and emissions dethreats of harm to human pose a new, potentially crease. dangerous activity should However, the situahealth or the environment, give proof of safety, rather tion is much less clear precautionary measures should with regard to the issue of than those potentially affected giving proof of preventive anticipation be taken even if some causedanger. and willingness to take Timothy O’Riordan action in advance of sciand-effect relations are not and Jones Cameron (2) entific proof of danger. A fully established scientifically.” complication is that, curalso note that precautionary principles should rently, the precautionary 1998 Wingspread statement advocate intrinsic naturprinciple is mostly apal rights and payments plied to uncertain effects for past ecological debt. The latter point targets those that may actually take place, whereas LCA calculates who have created large ecological burdens in the past scores related to potential effects that fundamentaland therefore must be “more precautious” than othly cannot be verified by experimental methods (18). ers, but the authors acknowledge that this concept is Despite the different applications, some observastill untested in law and in practice. (Intrinsic naturtions can be made. The precautionary principle clearal rights is more ethical in nature and, thus, outside ly is most relevant in situations in which no sufficient the scope of this commentary.) The Wingspread veror conclusive data exist on cause-and-effect relasion is one of the few documents that also demands tionships, and quantitative, probabilistic uncertainopeness, inclusion of affected parties, and examinaty analysis cannot be applied. In such situations, the tion of alternatives in the decision-making precautionary principle uses some kind of “weight of processelements that are mostly endorsed by the evidence” that includes suspicions and circumstanreview demands in ISO standards for LCAs that are tial evidence when the need and desirability for meadisclosed to the public (9). sures are assessed. Clearly, various interpretations of precaution exist. Here, mainstream LCA does not comply with preAn absolutist interpretation stipulates that if a degree caution. Virtually all major manuals for life-cycle imof safety cannot be proven, preventive measures to pact assessment (LCIA) rely heavily on models that erase the uncertain risk must be taken. Advocates of link environmental interventions with endpoints at this interpretation point out that too often action has the end of the emissions–effect chain, assuming reabeen delayed by calls for conclusive evidence of dansonable, even quantitative knowledge about these links. When uncertainties are at stake, the LCA comger (1). Other authors stress proportionality of remunity currently embraces probabilistic approachsponse, arguing that absolutist interpretations may es. LCIA is therefore currently heavily oriented toward fail to balance the seriousness of uncertain risks with assessing quantitative relationships between emiseconomic consequences (1, 16, 17). The Dutch sions and effects and probabilistic uncertainty analyScientific Advisory Council for Governmental Policy sis. Hence, LCIA does not deal well with situations for even introduced the notion of a societal/economic which the precautionary principle was developed. risk, which is defined as major, sudden changes in The parallel with quantitative risk assessment (RA), the production structure that form a risk to society which is often mentioned as being not in line with the and which should be weighed against reducing enviprecautionary principle, is obvious (1). ronmental risks (17). In a broader context, one could regard the precautionary principle as a representative concept of An example with chlorine principles related to democratic societal planning for These arguments can be illustrated with the Dutch sustainability. As my main goal is to analyze to what chlorine debate. A two-year study was performed extent LCA fits with the precautionary principle, I will during which 99% of the chlorine flows into the use the principle mainly in terms of judging its apNetherlands and all known related emissions were propriateness of response to uncertainty in individinventoried. Using LCIA, the relative toxicity of emisual management decisions. sions from the chlorine chain was calculated and compared with all emissions in the Netherlands. LCA encounters precaution Additionally, using existing RAs for the 50 most imWhen we compare the four central issues of the preportant substances, an analysis determined whether cautionary principle with LCA, it is clear that issues of risk levels would be exceeded. The results from all proportionality and burden of proof fall largely or fully these calculations were not too alarming, but our reoutside the scope of LCA. On the other hand, the point port also warned that this approach still left very imof opposing “assimilative capacity approaches” fits portant uncertainties and unknowns (19, 20). well with LCA. The most influential manuals and reThe Dutch Environment Minister, however, transports on LCA methodology are all based on the lesslated the apparently “hard” output from the LCIA and is-better philosophy. LCA does not give any premium RA calculations into a decision with only limited deto solutions that just dilute and disperse; all emissions, liberation. The Dutch Lower House was informed that as diluted as they are, are taken into account. In LCA, the “risks from chlorine and chlorine compounds are an alternative only can score better if a truly sourcemanageable” and that no overall chlorine policy was FEBRUARY 1, 2002 / ENVIRONMENTAL SCIENCE & TECHNOLOGY I 73 A

needed (21). Despite this statement, the Dutch chlorine debate continues. In follow-up research, we performed an in-depth argumentative analysis of the positions and views of different coalitions involved from 1985 to 1998 in the debates on chlorine in the Netherlands and polyvinyl chloride in Sweden. The analysis included a thorough literature review and a series of in-depth interviews with Dutch and Swedish stakeholders (20). We found that industrialists tend to follow an analytical framework based on a quantitative RAwhich we call a “risk assessment frame”—for which emission data are gathered, fate and exposure is quantitatively assessed, and the results are compared with a maximum daily intake. Furthermore, they emphasized the role of natural organochlorines and that current organochlorine concentrations in the environment may be the result of large past emissions. Finally, the industrialists felt it was an injustice to still be targeted for past environmental problems with substances like DDT, PCBs, and dioxins that had been phased out or are now handled more responsibly. They also objected to being judged on general policy problems, like the lack of empirical data on certain chemicals. Indeed, they expected that the data problems would be less severe for chlorinated substances than for other substances, given the extensive past debates on these compounds. Environmentalists tended to apply a more precautionary evaluation, which is related to what we call a “precautionary frame”. First, they stated that the chlorine industry has a long history of discovering hazardous substances produced as unintentional byproducts, including hexachlorobenzene, dioxins, and PCBs. Second, certain chlorinated solvents break down, in part, to relatively persistent chemicals in the atmosphere. Third, environmentalists also worry that only a small fraction of the organochlorines present in the environment can be identified. For example, well-known chlorinated hydrocarbons like PCBs and DDT make up less than 10% of the extractable organic chlorine complex in fish fat and Swedish sediments (22–25), and new classes of globally distributed organochlorines of unknown origin are still being discovered. Fourth, organochlorines generally exhibit undesirable properties such as persistence and bioaccumulation, which makes predicting their fate in complex food webs even more problematic and contamination irreversible. Finally, because of their tendency to exhibit these properties in common, these chemicals should be treated as a class rather than judged substance by substance. Since Greenpeace played an important role in both cases, it is not surprising that one of their former scientists, Joe Thornton, lists similar positions as ours (26). Thornton’s analysis presents other arguments, of which the tendency of chlorination to increase the toxicity of organic chemicals might be the most important one. Given the above arguments, environmentalists advocate the following about chlorine policy. Because 90% of the organochlorines in nature cannot be identified, ignorance “dominates” knowledge in this case and calculatory approaches can have only a limited role. Arguments one and three suggest that large gaps 74 A I ENVIRONMENTAL SCIENCE & TECHNOLOGY / FEBRUARY 1, 2002

exist in point source emissions control and monitoring systems. This picture indicates that humanity may still be irreversibly contaminating the environment with unknown chlorine compounds. Obviously, the environmentalists do not claim that this analysis is a final proof of danger. However, waiting until such incontrovertible proof is available is seen as an irresponsible approach to substance policy (27). Thus, environmentalists say it shows that a realistic probability of danger from continuing, irreversible contamination by unknown chlorine compounds exists. Irreversibility, in their opinion, is particularly undesirable because history has shown that even for wellknown substances, safety standards for contamination often had to be lowered. In addition, because other members in the chlorine family have proven to be quite problematic, suspicion cast on unidentified chlorinated substances is justified. Therefore, environmentalists assert that it is simply wise, from a precautionary viewpoint, to refrain from using chlorine if better alternatives exist. Hence, they claim that organochlorines have no place in a sustainable society, and these compounds should be prioritized, based on their relative danger, and phased out, with exceptions for those that serve essential purposes and lack an alternative (26). Some might see this as an example of a strong precautionary approach and not agree with the environmentalists’ analysis. Regardless, this example shows how a case for applying precautionary measures can be built. Current LCA methods do not take such a precautionary line of reasoning into account. LCA relies only on known emissions data, available data on substance properties, and subsequent quantitative modeling and is blind to the large fraction of unknown organochlorines in nature. Moreover, no distinction is made between production systems with a high or low chance of omissions in the emission inventory. Finally, LCA does not account for the fact that irreversible contamination can be important as a topic for evaluation in its own right. On these points, current LCA and the precautionary principle diverge, just as RA and the precautionary principle are often seen as opposing approaches.

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(10) Handbook on Life Cycle Assessment–Operational Guide to the ISO Standards; Guinée, J., Ed.; Kluwer Academic Publishers: Dordrecht, the Netherlands, in press. (11) Huijbregts, M. A. J.; et al. Chemosphere 2000, 41, 541–573, 575–588. (12) Best Available Practice Regarding Impact Categories and Category Indicators in Life Cycle Impact Assessment. Udo de Haes, H. A.; Jolliet, O.; Finnveden, G.; Hauschild, M.; Krewitt, W.; Müller-Wenk, R., Eds.; Int. J. Life Cycle Assess. 1999, 4 (2–3), 61–182. (13) United Nations Conference on Environment and Development. Rio Declaration on Environment and Development; 31 ILM 874; United Nations Press: New York, June 14, 1992. (14) Raffensperger, C.; Tickner, J. Protecting Public Health and the Environment: Interpreting the Precautionary Principle; Island Press: Washington, DC, 1999. (15) European Union. Communication From the Commission on the Precautionary Principle; Com (2000) 1 Final, 2.2.2000; Delegation of the European Commission to the United States: Washington, DC, 2000. (16) O’Riordan, T. The Precautionary Principle in Environmental Management. In Industrial Metabolism, Restructuring for Sustainable Development; Ayres, R. U., Simonis, U. A., Eds.; United Nations University Press: Tokyo, 1994. (17) WRR (Advisory Council on Government Policy). Duurzame Risico’s—Een Blijvend Gegeven; Sdu: The Hague, the Netherlands, 1994. (18) Heijungs, R. Economic Drama and the Environmental Stage. Formal Derivation of Algorithmic Tools for Environmental Analysis and Decision-Support From a Unified Epistemological Principle. Ph.D. Thesis, Leiden University, Leiden, the Netherlands, 1997. (19) Tukker, A.; Kleijn, R.; van der Voet, E. A Chlorine Balance for the Netherlands; TNO-STB Report 95/40; TNO and CML: Apeldoorn/Leiden, the Netherlands, 1995. (20) Tukker, A. Frames in the Toxicity Controversy. Risk Assessment and Policy Analysis Related to the Dutch

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Arnold Tukker is senior researcher/adviser at the Institute of Strategy, Technology and Policy of the Netherlands Organisation for Applied Scientific Research (TNO-STB). Address correspondence about this article to A. Tukker, TNO-STB, P.O. Box 6030, 2600 JA Delft, the Netherlands ([email protected]).

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