SUMMARY

Changes in rainfall patterns are a direct consequence of the current climate change. Climate projections indicate an intensification of extreme rainfall events (and floods), which will directly affect social, ecological, and economic systems. Thus, one of the greatest challenges of climate science is to understand, model, and predict the variability of floods both in temporal and spatial terms in the context of the present-day global warming. Nevertheless, the uncertainties in projected rainfall at regional scale are still high, and even higher in Mediterranean areas where the climate is characterized by extreme and sudden rainfall events. The instrumental record is too short to correctly estimate return floods periods. Thus, geological records are required to better understand the long-term variability, at millennial to decadal scales, of natural extreme flood events. Among the most important flood archives, including riverine and lake sediments, stalagmites represent one of the best geological records (i.e. accurate chronology, wide temporal range and good preservation) to study past flood frequency. However, stalagmites have not yet been properly exploited for this purpose. MODKARST will provide a unique opportunity to develop a quantitative flood database for the Western Mediterranean realm based on speleothems. To do so, the action plans to infer past flood events from the last 18,000 years based on detrital layers (indicative of flood events) recorded in stalagmites from 5 different caves. This data in combination with karst hydraulic models and water-level monitoring will allow to quantify past extreme flood events. MODKARST will help to better understand the relation among flood recurrence and climate changes, and will shed light on how to better predict the variability of floods in the context of present-day global warming.