Methods of representing uncertainties in climate sensitivity in integrated assessment modelling

By Bryant McAvaney

Paris 08th of June 2004

The climate sensitivity of models used in climate change research still displays a great deal of scatter. The IPCC range of 1.5K to 4.5K temperature change at doubling of CO2 has remained unchanged since the First Assessment Report. A number of international activities are underway to attempt: a) to gain greater understanding of the reasons for the uncertainty, b) quantify the probability distribution of the uncertainty range due to variations within models and variations between models, c) constrain the range of climate sensitivity from observations over the past century and over the past millennia. The seminar will present an outline of the overall problem and a description of the various techniques and, where possible, provide some preliminary results.