There are many ethical decisions that human beings make with respect to the environment. For example:
The academic field of environmental ethics grew up in response to the work of scientists such as Rachel Carson and events such as the first Earth Day in 1970, when environmentalists started urging philosophers to consider the philosophical aspects of environmental problems. Two papers published in Science had a crucial impact: Lynn White's "The Historical Roots of our Ecologic Crisis" (March 1967) and Garrett Hardin's " The Tragedy of the Commons" (December 1968). Also influential was Garett Hardin's later essay called "Exploring New Ethics for Survival", as well as an essay by Aldo Leopold in his A Sand County Almanac, called "The Land Ethic," in which Leopold explicitly claimed that the roots of the ecological crisis were philosophical (1949).
The first international academic journals in this field emerged from North America in the late 1970s and early 1980s – the US-based journal, Environmental Ethics in 1979 and the Canadian based journal The Trumpeter: Journal of Ecosophy in 1983. The first British based journal of this kind, Environmental Values, was launched in 1992.
(For more on Marshall's environmental ethics, see also: A. Marshall, 2002, The Unity of Nature, Imperial College Press: London. Alan Marshall is currently at Curtin University of Technology).
Andrew Brennan was an advocate of ecologic humanism (eco-humanism), the argument that all ontological entities, animate and in-animate, can be given ethical worth purely on the basis that they exist. The work of Arne Næss and his collaborator Sessions also falls under the libertarian extension, although they preferred the term "deep ecology." Deep ecology is the argument for the intrinsic value or inherent worth of the environment – the view that it is valuable in itself. Their argument, incidentally, falls under both the libertarian extension and the ecologic extension.
Peter Singer's work can be categorized under Marshall's ecologic extension. He reasoned that the "expanding circle of moral worth" should be redrawn to include the rights of non-human animals, and to not do so would be guilty of speciesism. Singer found it difficult to accept the argument from intrinsic worth of a-biotic or "non-sentient" (non-conscious) entities, and concluded in his first edition of "Practical Ethics" that they should not be included in the expanding circle of moral worth. This approach is essentially then, bio-centric. However, in a later edition of "Practical Ethics" after the work of Naess and Sessions, Singer admits that, although unconvinced by deep ecology, the argument from intrinsic value of non-sentient entities is plausible, but at best problematic. We shall see later that Singer actually advocated a humanist ethic.....
This category includes James Lovelock's Gaia hypothesis; the theory that the planet earth alters its geo-physiological structure over time in order to ensure the continuation of an equilibrium of evolving organic and inorganic matter. The planet is characterized as a unified, holistic entity with ethical worth of which the human race is of no particular significance in the long run.
Singer also advocated the preservation of "world heritage sites," unspoilt parts of the world that acquire a "scarcity value" as they diminish over time. Their preservation is a bequest for future generations as they have been inherited from our ancestors and should be passed down to future generations so they can have the opportunity to decide whether to enjoy unspoilt countryside or an entirely urban landscape. A good example of a world heritage site would be the tropical rainforest, a very specialist ecosystem or climatic climax vegetation that has taken centuries to evolve. Clearing the rainforest for farmland often fails due to soil conditions, and once destroyed can never be replaced.
Anthropocentrism simply places humans at the centre of the universe; the human race must always be its own primary concern. Therefore, everything else in existence should be evaluated in terms of its utility for us.
What Anthropocentric theories do not allow for is the fact that a system of ethics formulated from a human perspective may not be entirely accurate; humans are not necessarily the centre of reality. The philosopher Baruch Spinoza argued that we tend to assess things wrongly in terms of their usefulness to us. Spinoza reasoned that if we were to look at things objectively we would discover that everything in the universe has a unique value. Likewise, it is possible that a human-centred or anthropocentric/androcentric ethic is not an accurate depiction of reality, and there is a bigger picture that we may or may not be able to understand from a human perspective.
Peter Vardy distinguished between two types of anthropocentrism. A strong thesis anthropocentric ethic argues that humans are at the center of reality and it is right for them to be so. Weak anthropocentrism, however, argues that reality can only be interpreted from a human point of view, thus humans have to be at the centre of reality as they see it.
Only after 1990 did the field gain institutional recognition at programs such as Colorado State, the University of Montana, Bowling Green State, and the University of North Texas. In 1991, Schumacher College of Dartington, England, was founded and now provides an MSc in Holistic Science.
These programs began to offer a masters degree with a specialty in environmental ethics/philosophy. Beginning in 2005 the Dept of Philosophy and Religion Studies at the University of North Texas offered a PhD program with a concentration in environmental ethics/philosophy.