Abstract
The precautionary principle is a widely accepted policy norm for decision making under uncertainty in environmental management, However, some of the traditional ways of ensuring trustworthy results used in environmental science and of communicating them work contrary to the general goal of providing the political system and the public with as good an input as possible in the decision making process. For example, it is widely accepted that scientists should only communicate results fulfilling the traditional scientific standard for hypothesis testing. The need for introducing complementary norms in environmental science is illustrated by a recent discussion among scientists on how the precautionary principle should be used in the context of marine biological studies. This discussion highlights the importance of the use of statistical power in communicating scientific results to decision makers and to the general public as well as to the scientific peers. We argue that it would be unethical to report only certainties—because of the need of early warnings—and it would in the same way be unethical to hide the uncertainties. Environmental science can make a better contribution to environmental decision making, if the available knowledge is communicated in a manner which allows for insight on how strong the evidence is.