Environmental ethics examines the moral relationship between humans and the natural environment, including duties toward ecosystems, species, and future generations. The dominant historical position has been anthropocentrism, the view that human beings are the central or most important entities and that the environment has value only insofar as it serves human interests. Critics of this framework argue that it has justified widespread ecological destruction and overlooked the moral standing of non-human nature. A useful conceptual distinction runs between instrumental value, which is the value of something as a means to human ends, and intrinsic value, which is the value of something for its own sake, regardless of its usefulness to us.
Non-anthropocentric positions expand the circle of moral consideration in different ways. Biocentrism holds that all living beings have inherent moral value, not just humans, a view articulated by Paul Taylor in Respect for Nature (1986). Ecocentrism goes further by extending moral consideration to entire ecosystems, species, and ecological processes, valuing the health and integrity of the biotic community as a whole. Aldo Leopold's land ethic captures this with the famous formulation: "A thing is right when it tends to preserve the integrity, stability, and beauty of the biotic community. It is wrong when it tends otherwise." Deep ecology, founded by Arne Næss, advocates for the intrinsic value of all living beings regardless of their utility to humans and calls for fundamental changes in how humans relate to the natural world. The precautionary principle further supports environmental protection by placing the burden of proof on those proposing potentially harmful actions, even in the absence of full scientific certainty about the risks.
Climate change ethics raises especially complex questions of intergenerational justice, since current emissions impose harms on future generations who have no voice in present decisions. It also raises issues of responsibility between developed and developing nations that have contributed unequally to the problem. Garrett Hardin's tragedy of the commons describes how individuals acting in their own self-interest overexploit shared resources, leading to depletion that hurts everyone. Closely related to environmental ethics is animal rights ethics, which holds that animals have inherent moral rights and should not be treated merely as means to human ends. Tom Regan argued that animals are "subjects-of-a-life" with inherent value, while Peter Singer, in Animal Liberation (1975), argued that the capacity to suffer is the morally relevant criterion. Singer introduced the term speciesism, popularized by him but coined by Richard Ryder, to describe the unjustified preferential treatment of members of one's own species, drawing an analogy to racism and sexism. Together, these frameworks reshape moral philosophy to take seriously the interests of non-human animals, ecosystems, and future generations.