Environmental ethics considers the ethical relationship between human beings and the natural environment. It exerts influence on a large range of disciplines including law, sociology, theology, economics, ecology and geography. There are many ethical decisions that human beings make with respect to the environment. For example:

• Should we continue to clear cut forests for the sake of human consumption?
• Should we continue to make gasoline powered vehicles, depleting fossil fuel resources while the technology exists to create zero-emission vehicles?
• What environmental obligations do we need to keep for future generations?
• Is it right for humans to knowingly cause the extinction of a species for the (perceived or real) convenience of humanity?

Environmental ethics is properly but a sub-section of environmental philosophy, which includes environmental aesthetics, environmental theology, and indeed all the branches of philosophical investigation (e.g., epistemology, metaphysics, philosophy of science, etc).

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 an essay in Aldo Leopold's A Sand County Almanac, "The Land Ethic," in which Leopold explicitly claimed that the roots of the ecological crisis were philosophical (1949).

In the Journal of Applied Philosophy Alan Marshall writes of a natural ecological balance between the animate (living entities) and the inanimate (non-living entities) that existed for centuries (1993). For Marshall however, the rapid industrialization of the last 300 years has led to a major imbalance. Today growing concerns about global warming underline the general acceptance that environmental preservation is of vital importance. However, it is the grounds upon which one justifies the argument for or against preservation that is the subject of ethical debate, and this invariably includes a personal stance on non-human animal and non-animal rights.

There have been many attempts to categorize the different attempts to justify the importance of the preservation of the environment. Alan Marshall and Michael Smith are two recent examples of this, as cited by Peter Vardy in "The Puzzle of Ethics".

For Marshall, three ethical approaches have emerged over the last 20 years; the Libertarian Extension, the Ecologic Extension and Conservation Ethics.