Sufficiency is not a goal of environmental policy-making as is efficiency. In view of the planetary boundaries, this paper instead proposes that sufficiency should amend the notion of liberal society. The classic vision of liberal societies has been based on the core values of individual freedom, the no-harm principle and social justice together with the related virtues of courage, prudence and justice. By adding sufficiency, we introduce a fourth core value, one which is necessary for dealing with planetary boundaries. Temperance, the virtue linked to sufficiency, becomes an important part of this.