Communicating uncertainty in the IPCC 5th Assessment

Ever since the seminal work Moss and Schneider (1997), developing methods and language for accurate and honest communication of uncertainty has been a key element of the IPCC process. Following the recent Workshop in Stanford, new ideas are being put forward, particularly in distinguishing epistemic (lack of knowledge of governing equations) from aleatoric (inherent stochasticity in outcome) uncertainty. We would like to propose a short overview of the ideas and issues, followed by a discussion session to elicit ideas from the community on this issue to which Stephen Schneider made such a substantial and influential contribution.