Environmental ethics is an academic subfield of philosophy concerned with normative and evaluative propositions about the world of nature and, perhaps more generally, the moral fabric of relations between human beings and the world we occupy. This Handbook contains forty-five newly commissioned essays written by leading experts and emerging voices. The essays range over a broad variety of issues, concepts, and perspectives that are both central to and characteristic of the field, thus providing an authoritative but accessible account of the history, analysis, and prospect of ideas that are essential to contemporary environmental ethics. The Handbook includes sections on the broad social contexts in which we find ourselves (e.g., chapters on history, science, economics, governance, and the Anthropocene), on what ought to count morally and why (e.g., chapters on humanity, animals, living individuals, ecological collectives, and wild nature), on the nature and meaning of environmental values (e.g., truth and goodness, practical reasons, hermeneutics, phenomenology, and aesthetics), on theoretical understandings of how we should act (e.g., on consequentialism, duty and obligation, character, caring relationships, and the sacred), on key concepts (e.g., responsibility, justice, gender, rights, ecological space, risk and precaution, citizenship, future generations, and sustainability), on specific areas of environmental concern (e.g., pollution, population, energy, food, water, mass extinction, technology and ecosystem management), on climate change considered as the defining environmental problem of our time (e.g., chapters on mitigation, adaptation, diplomacy, and geoengineering), and on social change (e.g., pragmatism, conflict, sacrifice, and action).