Governing risks is not only a technical matter, but also a matter of ethical and societal considerations. In this article, we argue that in addition to scientific and technical uncertainties, we need to also address normative uncertainties of risk decisions. We define normative uncertainties as situations where there are different partially morally defensible -- but incompatible -- options or courses of action, or ones in which there is no fully morally defensible option. We conceptualize normative uncertainties, distinguishing between the four categories of evolutionary, theoretical, conceptual, and epistemic normative uncertainties. We will show different instances of normative uncertainties in climate adaptation strategies. We finally present two methods for identifying and dealing with normative uncertainties, namely, the Wide Reflective Equilibrium and adaptive planning. Situations of normative uncertainties have always been and will continue to be present in risk decisions and they have often been dealt with in an implicit manner. In this article, we make them explicit, which could lead to better morally informed and justified decisions about climate risks. This article is categorized under: Climate, Nature, and Ethics > Ethics and Climate Change.

In this paper we suggest considering sustainability as a moral framework based on social justice, which can be used to evaluate technological choices. In order to make sustainability applicable to discussions of nuclear energy production and waste management, we focus on three key ethical questions, namely: (i) what should be sustained; (ii) why should we sustain it; and (iii) for whom should we sustain it. This leads us to conceptualize the notion of sustainability as a set of values, including safety, security, environmental benevolence, resource durability, and economic viability of the technology. The practical usefulness of sustainability as a moral framework is highlighted by demonstrating how it is applicable for understanding intergenerational dilemmas—between present and future generations, but also among different future generations—related to nuclear fuel cycles and radioactive waste management.