Addressing how to manage the science-policy interface, this book presents a philosophical study of the issues surrounding uncertainty in scientific simulation, particularly concerning the role it plays in public policy regarding climate change. The author, who participated in the United Nations' Intergovernmental Panel on Climate Change (IPCC) plenaries in 2001 and 2007, discusses the assessment reports of the IPCC and explains the workings of the IPCC. This second edition reflects the latest developments in climate change policy.