Evaluation, characterization, and communication of uncertainty by the intergovernmental panel on climate change—an introductory essay

Abstract

Since its inception in 1988, the Intergovernmental Panel on Climate Change (IPCC) has worked with the growing recognition that uncertainty is pervasive in our understanding of the climate system: what drives climate change, what will determine its future course, and what influence it will have on important social and ecological aspects of our world. It is not news that the IPCC has struggled, with varying degrees of success, in its efforts to describe these uncertainties and to judge the confidence with which it can offer its major conclusions. Richard Moss and Stephen Schneider (Moss and Schneider 2000) were the lead authors of IPCC’s first attempt to provide some guidance for authors in this regard, during the preparation of the Third Assessment Report (the TAR). A second guidance document was created by an author team headed by Martin Manning and Rob Swart (Manning et al. 2004) after an expert meeting to support the Fourth Assessment Report (AR4), and yet another version was produced after another expert meeting by a cross-working group team (Mastrandrea et al. 2010) as chapter authors assembled to begin their work on the Fifth Assessment Report (AR5). This most recent attempt, informed by the history of previous assessments, is the point of departure for the papers in this special issue of Climatic Change.