The most varied media outlets are currently reporting on environmental impacts or damage and the difficulty public authorities have in combating them effectively. Since the formation of Federalism in Brazil, with the decentralisation of political power and the constitutional distribution of competences, this work has sought to analyse the actions of the federal entities in dealing with the environmental challenges of everyday life. The aim was to demonstrate that the application of the principle of subsidiarity in conjunction with the theory of implied powers is necessary in order to provide municipalities, where people live and where environmental impacts occur, with the means and resources necessary to face environmental challenges in cooperation with the Union and the States, using the environmental protection adopted by the countries of the European Union as an example to be studied. This book thus seeks to present theories, propose solutions, but above all arouse the reader's interest in the Study of Environmental Federalism, which we see as a major challenge today.