The field of environmental ethics concerns human beings’ ethical relationship with the natural environment. While numerous philosophers have written on this topic throughout history, environmental ethics only developed into a specific philosophical discipline in the 1970s. This emergence was no doubt due to the increasing awareness in the 1960s of the effects that technology, industry, economic expansion and population growth were having on the environment. The development of such awareness was aided by the publication of two important books at this time. Rachel Carson’s Silent Spring, first published in 1962, alerted readers to how the widespread use of chemical pesticides was posing a serious threat to public health and leading to the destruction of wildlife. Of similar significance was Paul Ehrlich’s 1968 book, The Population Bomb, which warned of the devastating effects the spiraling human population has on the planet’s resources. Of course, pollution and the depletion of natural resources have not been the only environmental concerns since that time: dwindling plant and animal biodiversity, the loss of wilderness, the degradation of ecosystems, and climate change are all part of a raft of “green” issues that have implanted themselves into both public consciousness and public policy over subsequent years. The job of environmental ethics is to outline our moral obligations in the face of such concerns. In a nutshell, the two fundamental questions that environmental ethics must address are: what duties do humans have with respect to the environment, and why? The latter question usually needs to be considered prior to the former. In order to tackle just what our obligations are, it is usually thought necessary to consider first why we have them. For example, do we have environmental obligations for the sake of human beings living in the world today, for humans living in the future, or for the sake of entities within the environment itself, irrespective of any human benefits? Different philosophers have given quite different answers to this fundamental question which, as we shall see, has led to the emergence of quite different environmental ethics.