Abrupt fluctuation of northern Mediterranean hydroclimate and North Atlantic Oscillation since the middle Holocene

The North Atlantic Oscillation (NAO) has been considered as one of the essential drivers of modern climate change. Its multi-decadal variability and the teleconnection with global climate system, however, is poorly known because of the lack of continuous and highly resolved paleoclimate records. Here we show a multi-annually resolved precipitation record from the northern Mediterranean region to retrieve NAO variability since the middle Holocene inferred from stalagmite oxygen stable isotope records from northern Italy. This record and our simulations showt insolation-induced millennial non-stationary behaviors of the NAO. The revealed irregularly-spaced hydroclimatic fluctuations with multidecadal-to-multicentennial wet/dry events and rapid shifts within a few decades, especially over the last three thousand years, are strongly coupled with tropical Pacific thermal conditions. Our results provide clues of potentially more frequent rapid regional hydroclimate change in the future.