Making environmental policy is essentially an act of balancing the short-term economic interests of present generations and the long-term environmental benefits of posterity. Such balancing ultimately rests on a value judgment, which is formed on the basis of economic, ethical, and scientific considerations of stakeholders. This chapter focuses on the latter aspect of environmental policy-making, namely, the problems that arise in taking into due account the scientific facts in such balancing. It will explore the reasons why scientific warnings on environmental degradation or the risk thereof are often incapable of driving policy decisions, and it will discuss how invoking trust obligations of States may promote a balance that is more sensitive to scientists’ inputs.