Central Mediterranean rainfall varied with high northern latitude temperatures during the last deglaciation

Central Mediterranean rainfall variability during the last deglaciation was closely linked to temperatures at high northern latitudes through strengthened westerly winds, as suggested by speleothem proxies from southern Italy. Similarly to the effects of current climate change, the last deglaciation (Termination I) rapidly altered northern latitude temperatures and ice-sheet extent, as well as the Atlantic Meridional Overturning Circulation. However, it is still unclear how these changes propagated and impacted the central Mediterranean continental rainfall variability. This prevents a full understanding on how global warming will affect Mediterranean areas in the future. Here, we present a high-resolution reconstruction of rainfall changes in the central Mediterranean across Termination I, based on a novel delta O-18 time series from a southern Italian stalagmite. Across Termination I the availability of Atlantic moisture varied in response to northern latitude temperature increases (decreases) and ice-sheet decreases (increases), promoting a higher (lower) intensity of the Atlantic Meridional Overturning Circulation, and resulting in a relatively wetter (drier) climate in the Mediterranean. In the light of future warming, this study emphasises the role of high-latitude climate changes in causing rainfall variation in highly populated Mediterranean areas.

Automated summary

This study suggests that rainfall variability in the central Mediterranean during the last deglaciation was closely linked to temperatures at high northern latitudes and influenced by strengthened westerly winds. The findings highlight the importance of high-latitude climate changes in causing rainfall variation in the Mediterranean region.