Conceptual development and use of downscaled climate model information

Statistical and dynamical downscaling techniques are widely applied in the development of local climate change scenarios. This talk traces the conceptual development of downscaling as a decision-support tool for climate risk assessment, resilience and adaptation planning. Four epochs are identified: (1) early exploration of local changes in key climate variables, such as temperature and precipitation extremes; (2) application of downscaled scenarios to climate impacts modelling (such as for agriculture yield or water resource assessments); (3) advent of ensemble-based methods and more sophisticated handling of uncertainty in the downscaling-impacts workflow; and (4) use of downscaled scenarios to stress-test adaptation options under plausible ranges of climate and non-climatic conditions. Each phase is illustrated by and reflected in the development of the Statistical DownScaling Model – Decision Centric (SDSM-DC) over more than two decades. Questions around fitness for purpose and appropriate uses of the tool are explored. The talk concludes by considering: where next for downscaling?