Last interglacial hydroclimate in the Italian Prealps reconstructed from speleothem multi-proxy records (Bigonda Cave, NE Italy)

Past climate archives show the Last Interglacial (LIG) period as similar to slightly warmer than current temperatures. However, there is a lack of LIG proxy evidence regarding variations of the climate across large topographic features and how this manifests at different altitudes. Here, we analysed two flow-stones from Bigonda Cave, northeast Italy, to reconstruct LIG climate conditions in a region where precipitation is strongly influenced by the presence of the Alps. Stable isotope ratios, trace element concentrations and speleothem petrography from 133 ka to 105 ka allowed the detection of various hydroclimate and environmental conditions. Composite speleothem delta O-18 records from northeast Italy were found to closely follow the Northern Hemisphere summer insolation curve, attesting to the influence of solar isolation on Earth's hydroclimate. Our reconstructions indicate a northward shift of the Intertropical Convergence Zone during the LIG maximum, permitting Atlantic-derived moisture to travel further east across North Africa than at present, before being directed north towards the Alps. The latter part of the LIG exhibited frequent, extreme precipitation events in the SE Prealps due to orographic lifting of moisture from both the Atlantic and Mediterranean seas. Socio-economic planning must prepare for extreme autumnal flooding events and serious summer droughts, particularly important in vulnerable mountainous regions. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

Research indicates that during the Last Interglacial period, climate was similar to or slightly warmer than current temperatures, with some differences. Variations in solar insolation and sources of moisture have a significant impact on Earth's hydroclimate, especially in regions prone to frequent extreme climate events.