Environmental norms are observed because they are norms about how people respect each other and the natural systems that sustain human communities. Environmental norms are basic to human well-being. They arise out of the human condition, not unlike human rights laws. Environmental norms emerge from the fact that humans exist within ecosystems, and human society is embedded in the natural systems in which they have evolved; environmental norms are grounded in an objective reality, and scientists can measure the consequences of observing--or failing to observe--those norms. The provisions of environmental norms, therefore, exist not merely as pronouncements of governments, applied solely by the force of the state; legal positivists see norms as effective only if adopted as a law, and when backed by effect sanctions. Indeed, like other fundamental rights, the right to live in a sound environment is assumed by many to be a “given,” and some courts and many constitutions now recognize this right.
Nicholas A. Robinson, Enforcing Environmental Norms: Diplomatic and Judicial Approaches, 26 Hastings Int'l & Comp. L. Rev. 387 (2003), http://digitalcommons.pace.edu/lawfaculty/370/.