This essay offers a critique of environmental ethics and argues that a post-environmental ethics may be unavoidable. It does so by exposing and questioning the ontological assumptions common to otherwise different modalities of environmental ethics. These modalities, it is argued, rest upon an implicit or explicit 'material essentialism'. Such essentialism entails the belief that putatively 'environmental' entities have discrete and relatively enduring properties. These properties 'anchor' ethical claims and permit the objects of ethical considerability to be named. Against this, it (...) is argued that a non-essentialist ontology is preferable. This ontology presumes neither that environmental phenomena are simply environmental nor that their properties can be 'fixed' under some determinate description. Drawing on recent 'hybrid' research in human geography and elsewhere, it is suggested that the motility and mutability of ostensibly environmental entities be recognised. This recognition, I conclude, desta bilises conventional environmental ethics and calls for a more supple mode of ethical reasoning. (shrink)