Intergenerational justice has become a central guiding principle of climate policy. It combines normative, legal, and economic perspectives on the fair distribution of freedoms, costs, and opportunities between current and future generations. This article shows that intergenerational justice is not a moral ideal, but rather a constitutional and economically justified imperative for action. Using Germany as an example, it analyses the extent to which political and fiscal mechanisms are suitable for ensuring intertemporal responsibility. Intergenerational climate policy does not appear to be a programme of renunciation, but rather an economically rational investment in the future viability of society and the economy.