The word “consensus” does not appear in the first report of the Intergovernmental Panel on Climate Change back in 1989. It appears prominently, however, when scientists associated with Working Group I represented the report’s findings to the public. This early commitment to “consensus” talk legitimated opponents’ attacks on the existence of a scientific consensus, locked the scientific community in to defending a rigid position, and lead the public debate in unhelpful directions for twenty years. There were alternatives.