ABSTRACT
This chapter reviews the origins of sustainable development as a concept and examines its meaning in international law. It discusses the definitions of 'development', 'sustainability' and 'sustained yield' in current literature, along with their inception in natural resource management and economics. The chapter considers the evidence, in UN General Assembly resolutions, international tribunal decisions, treaties, and international environmental law literature, that sustainable development could be characterized as an emerging 'principle of customary international law'. The United Nations Conference on Sustainable Development – or Rio+20 – took place in Rio de Janeiro, Brazil on 20–22 June 2012, and resulted in a focused political outcome document laying out clear and practical measures for implementing sustainable development. State practice demonstrating that sustainable development is now a principle of international law could be discerned from many sources, including broad ratification of treaties on sustainable development; the records or travaux preparatoires of international negotiations and conferences which document formal notes or statements by State representatives.
