Assessment of Uncertainty in Climate Change Projections
July 2006 until June 2008
Thomas Schneider von Deimling
PIK number / OEH

ASSERT aims to provide global warming projections that are robust under climate model uncertainty, thereby working at the interface of “climate modelling” and “Integrated Assessment of climatic change under uncertainty”. In practical terms, ASSERT constrains model parameter uncertainty by running huge ensembles of perturbed parameter physics. The focus hereby is on climate sensitivity (CS), a key model characteristic of high importance both to the modelling as well as to the Integrating Assessment (of climatic change) community. Recent studies of CS uncertainty has left the community with a very broad range for CS that would make Integrated Assessment of climatic change a formidable task: societies would have to take into account too many possibilities (degrees of global warming) to adjust to. A key objective of ASSERT is to reduce uncertainty in CS by accounting for various climatic archives, especially paleo-data from the LGM (Last Glacial Maximum, 21 kyrs BP) and regional temperature changes of 20th Century warming. Results gained in ASSERT will be used for project PRIMAP for a probabilistic assessment of emission paths.