This thesis examines the emergence of the environmental movement as part of a larger process of increasing conscientiousness about environmental protection. It looks at how the international UN conferences on the environment in 1972 and 1992 contributed to the formation of this movement, and the concept of the environment, by opening discursive space and allowing for democratic participation. The discussion uses concepts developed by Jurgen Habermas, in his theory of communicative action, to highlight the importance of the public sphere and the role of civil society in this process. However, a comparison of the participation of Brazil and the USA in the two conferences raises questions about the application of this theory. In order to explain the activity of these countries and the changes that occurred during the 20 years that separate the conferences a different perspective is presented. Ideas inspired by Michel Foucault provide a methodological discussion, which permits an analysis of the emergence of the environmental movement in Brazil and the USA. In addition, it contextualizes their participation in the international conferences and helps understand the turn in the international community towards a focus on development. Finally, as a result of the tensions that arise between Habermas and Foucault s perspectives, the limits and contributions of these authors for the herein analysis are uncovered.