This special symposium grew out of a workshop held in Hamburg in 2011 (Krauss and von Storch 2012) and of a long-term interest in climate research as post-normal science. A decade earlier, Dennis Bray and Hans von Storch (1999) stated that the management of uncertainty and its extension into the political and social realm make climate science a case for post-normal science. Interpreting a survey among German and American climate scientists, they suggested that scientific policy advice is the result of both scientific knowledge and normative judgment.