Global society’s actions have created a planetary state whose dynamics are new to human experience-the Anthropocene. One consequence is that alarming climatic, ecological, and public health trends are unfolding with little evidence of abating. This essay argues that the convergence of these trends could lead to a comprehensive crisis where multiple risks materialize in reinforcing ways-the crisis of the Anthropocene. This crisis is likely to occur near the high population point of the demographic transition in progress. Ensuring that the demographic transition is also a transition to sustainability will require conceptualization and planning that internalizes the synergism of threats to society and nature.