Scientific information about the current state of the environment and environmental trends is crucial.
Economic factors are also important.
Ethical principles, as well as factual predictions about the consequences of various alternative policies, need to be considered. Questions of value are also important. Finally, it is necessary to take account of environmental law. It is important to have an understanding both of current law and of what legal change is possible. Foundations of Environmental Law and Policy , edited by Richard L. Revesz, views environmental policy primarily through the lenses of economics, ethics and law.