Events

Stefan Brönnimann Oeschger Centre for Climate Change Research Chair of Climatology & Managing Director Institute of Geography, University of Bern "Learning From Past Weather" Climate change is more than an increase in mean temperature. What affects most of us more strongly is the change in weather, in the frequency or intensity of extreme events. As extreme events are rare, long records are needed. Since decades, reconstructions of past climate have helped us to better understand how the climate system works and why climate varies. Likewise, weather reconstructions now help us to understand weather variations. Progress in data assimilation today allows reconstructing the global atmosphere (termed reanalysis) with only sparse surface observations. Such observations are uncovered in recent data rescue efforts. Using regional models, a global reanalysis can be further downscaled to the local scale. The output can be used to drive impact models, whose output can then be compared with historical documents. In this presentation I will describe the methods to reconstruct past weather on a global and local scale based on data rescue efforts, reanalyses, and numerical downscaling. I will present examples of past extreme events reaching back to the 18th century, and examples of impact modeling. The new approaches also re-value the use of historical documentary data for climate science and lead to a new collaboration between historians and scientists.