Brazil shares around 4% of the global carbon emissions. Three dimensions of Brazilian participation in the global carbon cycle are unique: 1- It is the only middle income country in which a high proportion of emissions (around half) comes from deforestation; 2- 85% of its electricity is derived from hydropower, being among the top three in the world; and, 3- In the last three decades it has mass produced ethanol as a fuel for transportation. In spite of its low carbon intensive matrix, Brazil has not taken a more active role in regional (South American) and Global Climate change mitigation because its failure in controlling deforestation has shaped its climate change policy. Different from most emerging countries, the cost of emission reduction would be low in Brazil because deforestation control would have a marginal impact on gross national product. This paper will analyse the evolution of Brazilian national and international climate policy. It will focus on recent changes in public opinion and the debate inside the Brazilian government and society about what Brazil’s stand should be in the current negotiations of a post-Kyoto architecture for climate change mitigation and adaptation.