1972: The UN Conference on the Human Environment held in Stockholm brought the industrialized and developing nations together to delineate the rights of the human family to a healthy and productive environment.

1980: The International Union for the Conservation of Natural Resources published the World Conservation Strategy (WCS), which provided a precursor to the concept of sustainable development.

1983: The World Commission on Environment and Development was created. The commission was asked to formulate a global agenda for change. In 1987, in its report Our Common Future, it advanced the understanding of global interdependence and the relationship between economics and the environment previously introduced by the WCS.

June 1992: The first UN Conference on Environment and Development was held in Rio de Janeiro and adopted an agenda for environment and development in the 21st century. Agenda 21, a program of action for sustainable development, contains the Rio Declaration on Environment and Development, which recognizes each nation's right to pursue social and economic progress and assigned to states the responsibility of adopting a model of sustainable development.

2002: Ten years after the Rio Declaration, a follow-up conference, the World Summit on Sustainable Development was convened in Johannesburg to renew the global commitment to sustainable development.

(Source: www.uncsd2012.org)