Abstract
In this paper, the notion of sustainability as a general regulative idea is distinguished from sustainable development as a more concrete concept leading to practical actions. After that, different economic meanings of sustainable development are discussed, and a concept of critical sustainability is proposed especially with respect to the problem of climate change. Maintaining critical crash barriers and bottlenecks presupposes, however, demanding, continuous improvements in energy efficiency. After discussing problems of decision theory in cases of uncertainty, which is constitutive for climate change, the links between intragenerational and intergenerational justice are analyzed, and by using Barry's notion of justice and Goodin's concept of vulnerability, two possible positions of the general idea of fairness inherent in sustainable development are presented. We conclude by shortly sketching the notion of sufficiency as an additional supplementary sustainability strategy in cases where efficiency improvements based on innovation are less than sufficient for securing the (energetic) fundaments of economic activity and human life.