摘要:This article analyses thresholds of catastrophe guiding measures to fight the Covid-19 pandemic and climate change. It argues that in both cases thresholds express the proposed interaction between the security technologies of prevention and preparedness. Preventive measures are supposed to slow down the infection dynamic and the rise of global temperatures, so that strategies of preparedness are able to cope with the remaining adversities: effectively treating patients and successfully adapting to climate change. The transgression of the catastrophe threshold thus marks the point when crisis dynamics become uncontrollable. The goal is to prevent the unpreparable and to prepare for the unavoidable. A moral economy of life underpins this rationality by providing a backstop against an excess of biopolitical elasticity in setting the threshold. The paper contributes to debates in security studies and the sociology of risk by showing how prevention and preparedness, which are often assumed to be opposing rationalities, come to operate in the same security assemblages. In addition, the paper criticizes the ways in which the focus on the catastrophe threshold silences death and suffering below the threshold and fails to provide guidance for situations when the threshold is already breeched. Considering the advanced state and the peculiar temporality of the climate crisis, the paper analyzes a shift from “pre” (preparedeness, prevention) to “re” (carbon removal, ecological remediation and reparation) in the contemporary politics of environmental security.