Giovanni Coletti, Laura Borromeo, Luca Fallati, Marco Luppichini, Agostino Meroni, Francesco Maspero, Elisa Malinverno, Monica Bini, Daniela Basso, Giovanni Vezzoli, Eduardo Garzanti, Valentina Alice Bracchi, Alessandra Savini, Fabien Desbiolles, Claudia Pasquero, Annamaria Correggiari, Irene Cornacchia, Chiara Boschi, Ilaria Baneschi, Alessandro Cavallo, Matteo Masotta, Giulia Bosio, Andrea Gallerani, Nicoletta Fusi, Luca Mariani, Anna Galli, Sergio Andò, Sirio Consani, Marco Lazzarotti, Gregorio Taccola

Understanding Earth’s changing climate is a crucial challenge. However, the available time series of direct measurements are often insufficient to fully capture climatic process that unfolds over centuries and millennia. Combining History and Geology can fill this gap. Focusing on rainfall and flood events, this research proposes a multidisciplinary approach to integrate the sedimentary and meteorological records of the Magra River (Northern Italy), using historical data as a bridge between the two datasets. A pristine record of shallow-water shelf sediments, collected at the mouth of the river and covering the last thousand years, is analysed interpreting sand layers as flood events. The results are compared with a coherent historical record of floods and river activity spanning six centuries and instrumental measurements spanning two centuries. The geological data are reasonably consistent with rainfall data and historical records, testifying for the reliability of the river mouth sedimentary record as a proxy for river discharge. The complete dataset and the comparison with other basin of the northwestern Mediterranean indicate common floods during the second half of the XII, XIV, XVI and XVIII centuries, and at the beginning of the second half of the XX century, all periods characterised by predominantly negative phases of the North Atlantic Oscillation.