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Is the precautionary principle applicable to the subject of extinction? It has, in fact, been applied to this question by several official documents.359 In order to motivate the precautionary principle, the Wingspread document explicitly mentions extinction as one of the areas where traditional decision methods have failed.360 The Rio declaration does not explicitly talk about extinction, but claims that the precautionary principle should be used in situations of (a) serious damage, (b) irreversible damage, and (c) lack of full scientific certainty. These are all salient aspects of species extinction: The extinction of species is typically irreversible. There are many uncertainties concerning the species issue. There are suspicions that extinction will harm some very important values. There are nonlinear effects that increase the uncertainties,361 and make the question of timing extra important. If the species loss results in a loss of an ecosystem service, that too, will typically be an irreversible loss, and a very serious one. All of the things mentioned here turned out in section 3.3 to be precisely the kinds of things that the precautionary principle is meant to deal with.

Bryan G. Norton compares the rivet popping analogy by Ehrlich and Ehrlich (see section 2.7 above), to a phenomenon called “zero-infinity dilemmas”.362 A zero-infinity dilemma is a situation in which the probability for something to go wrong is very small, while the effects if it does are

358 Gee 2006

359 Cooney 2005 pp.6f, Cooney & Dickson 2005 pp.10f, Cooney & Dickson 2005:2 p.xxi, McGarvin 2001 p.23

360 Wingspread Conference 1998

361 Daily 2000 p.336

362 Norton 1986:1 p.121, Norton 1987 pp.67ff

catastrophic.363 If too many species disappear from an ecosystem, the ecosystem may break down. The same could, according to Norton, be the case with the entire biosphere. For each single species, the probability that the extinction of that particular species would cause the breakdown is very small, but if it does, the consequences would be very serious indeed.364

This too, looks like a good reason for applying the precautionary principle to the question of extinction. The important thing to note is that the principle tells us not to be satisfied with an ordinary risk analysis. It urges us to take into account the uncertainty concerning the probability (there is no way we can know in advance whether the species in question will be the one that causes the break down). It also urges us to consider both the value of the ecosystem at risk, the harm that may be caused to this value, the uncertainties concerning these aspects, and the aspect of irreversibility. It finally tells us that as a result of these considerations we must adjust, and quite possibly, the burden of proof for those who want to take the risk.

Norton is not alone in concentrating on the possible breakdown of ecosystems and the loss of ecosystem services. The UN Millennium Ecosystem Assessment group also belongs to this category. They reason in three steps:

2. They start by pointing out that working ecosystems provide us with many important ecosystem services.

3. They then stress the importance of biodiversity for properly working ecosystems.

4. Finally, they argue that since so much is at stake, and since we have good reasons to believe that biodiversity is important for the ecosystems to work, but do not know exactly how, we ought to apply the precautionary principle.

In our case, since the ecosystem services are very valuable and since there is a strong suspicion that loss of biodiversity may eventually be detrimental to this value, we should demand very strong evidence that the species under consideration will not be the one that breaks the neck of an ecosystem service.

However, since we cannot know that in advance, we ought instead to demand good evidence that a certain practice will not cause extinction.

Protection of ecosystems and ecosystem services is not the only reason to apply the precautionary principle to the species issue, however. Other species supply us with a host of different instrumental values. In some cases the exploitation of these values risk causing extinction of the species. As we have seen, exploiting a species to the degree that it goes extinct may in some cases be economically rational from an anthropocentric viewpoint. This is, however, something we do not always know for sure. In sub-section 3.3.2 we noted that when an act might result in an irreversible change, we need extra strong evidence against any suspicion that the change will result in serious problems, for

363 This is the standard definition. Norton adds a list of other criteria that are characteristic of extinction in particular. I believe, however, that the simpler standard definition is sufficient for the point I am going to make.

364 Norton 1986:1 p.121, Norton 1987 pp.67ff

example, by destroying or depleting a resource that would afterwards turn out to be more valuable in its original state. This is clearly applicable to the situation we discuss here. Extinction is, as we have seen, irreversible (at least in practice if not in theory) and we cannot know now what the value of the species will be for future generations of human beings. We also have to remember that there are much uncertainty regarding the function of ecosystems and the relations between different species. We have not even discovered all species yet, and many of the species that are discovered are quite poorly described. Many of these species may, in the future, turn out to be important e.g. for medicine or agriculture,365 and at least some of the species for which we have found no direct use, may in the future evolve in such a direction that they will become useful. Some species are probably also important for the future existence or development of other species that in turn will become useful. When combined with the irreversibility of extinction, and with the extensive historical evidence that species have time and again turned out to be valuable in unexpected ways,366 it seems that we have a strong reason to place a rather heavy burden of proof on projects that might result in the extinction of species.

365 Regan, Donald H 1986 p.195

366 Gärdenfors 2005 p.119