Abstract

The United Nations Conference on the Human Environment held in Stockholm in 1972, twenty years before the Earth Summit in Rio in 1992, marked the fi rst milestone in the history of international cooperation for the environment. The 1992 Rio summit delivered the fi rst global agreement on climate change control. Twenty + twenty years later, the Rio + 20 conference, scheduled to be held in June 2012, will open a new stage in international negotiations with the participation of developing countries, and its focus will be broadened to include a debate on the global and sustainable «development that meets the needs of the present without compromising the ability of future generations to meet their own needs».