Climate changes predicted for Brazilian Amazonia place much of the forest in danger of dieoff from the combined effect of drought and heat within the current century, and much sooner for some areas. Increases are expected in the frequency and magnitude of droughts from both the El Niño phenomenon and from the Atlantic dipole. These changes imply increased frequency of forest fires. Forest death from drought, fires or both would be followed by a transformation either to a savanna or to some type of low-biomass woody vegetation, in either case with greatly reduced biodiversity. This risk provides justification for Brazil to change its negotiating positions under the Climate Convention to accept a binding target now for national emissions and to support a low atmospheric concentration of carbon dioxide (400 ppmv or less) as the definition of “dangerous” interference with the climate system.