The Potential of Speleothems from Western Europe as Recorders of Regional Climate: A Critical Assessment of the SISAL Database

Western Europe is the region with the highest density of published speleothem delta O-18 (delta O-18(spel)) records worldwide. Here, we review these records in light of the recent publication of the Speleothem Isotopes Synthesis and AnaLysis (SISAL) database. We investigate how representative the spatial and temporal distribution of the available records is for climate in Western Europe and review potential sites and strategies for future studies. We show that spatial trends in precipitation delta O-18 are mirrored in the speleothems, providing means to better constrain the factors influencing delta O-18(spel) at a specific location. Coherent regional delta O-18(spel) trends are found over stadial-interstadial transitions of the last glacial, especially in high altitude Alpine records, where this has been attributed to a strong temperature control of delta O-18(spel). During the Holocene, regional trends are less clearly expressed, due to lower signal-to-noise ratios in delta O-18(spel), but can potentially be extracted with the use of statistical methods. This first assessment highlights the potential of the European region for speleothem palaeoclimate reconstruction, while underpinning the importance of knowing local factors for a correct interpretation of delta O-18(spel).