Environmentalists have always valued the idea of thinking globally--and the idea of the Anthropocene is certainly a planetary thought. That thought, of course, is that Earth has entered a new geological epoch, characterized most determinately by human activity. To speak precisely, geologists have advanced the hypothesis that at this moment (geologically speaking) human activity is making a detectable contribution to the materials presently forming the rock that will be an entry in Earth's "permanent record." On this hypothesis, observers in the distant future will be able to observea geological stratum marking a boundary between two broadly distinct conditions of the Earth system: the Holocene coming before, and the Anthropocene coming after. But what originated within geology has come to assume a less specific meaning and a wider significance. I wish to explore one particular sort of significane: the implications of the Anthropocene for ethical thinking about human activity in the environment.