The circum-Mediterranean region is the cradle of ancient civilizations that had their roots in the Holocene. Climate change has been considered a key element that contributed to their rise or fall. The Roman Warm Period (RWP), 200 B.C. to 400 A.D., was the warmest period in Europe during the last two thousand years. Hydroclimatic change at the end of the RWP has been suggested as a possible influence on the stability of the Roman political regime and the eventual collapse of the Roman Empire in 476 A.D. A lack of precise proxy records hampers our understanding of hydroclimatic variability over the RWP. Here we present a stalagmite-based climate record from 550 ± 10 B.C. to 950 ± 7 A.D. (2σ) from northern Italy, which reveals a climatic trend of warming and increased humidity throughout the RWP. By comparison with other proxy records in Europe and the circum-Mediterranean region, we argue that the warm, humid climate in southern Europe could be linked to the multi-centennial warming of the Mediterranean Sea. Our record further suggests a century-long rapid drying trend from the early-4th to early-5th century, followed by a 100-year-long drought event, which could have influenced the fall of the Roman Empire.

The variability of the northern westerlies has been considered as one of the key elements for modern and past climate evolution. Their multiscale behavior and underlying control mechanisms, however, are incompletely understood, owing to the complex dynamics of Atlantic sea-level pressures. Here, we present a multi-annually resolved record of the westerly drift over the past 6,500 years from northern Italy. In combination with more than 20 other westerly-sensitive records, our results depict the non-stationary westerly-affected regions over mainland Europe on multi-decadal to multi-centennial time scales, showing that the direction of the westerlies has changed with respect to the migrations of the North Atlantic centers of action since the middle Holocene. Our findings suggest the crucial role of the migrations of the North Atlantic dipole in modulating the westerly-affected domain over Europe, possibly modulated by Atlantic Ocean variability.

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 δ¹⁸O 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.

The Marine Isotope Stage (MIS) 11c interglacial and its preceding glacial termination represent an enigmatically intense climate response to relatively weak insolation forcing. So far, a lack of radiometric age control has confounded a detailed assessment of the insolation-climate relationship during this period. Here, we present ²³⁰Th-dated speleothem proxy data from northern Italy and compare them with palaeoclimate records from the North Atlantic region. We find that interglacial conditions started in subtropical to middle latitudes at 423.1 ± 1.3 thousand years (kyr) before present, during a first weak insolation maximum, whereas northern high latitudes remained glaciated (sea level ~ 40 m below present). Some 14.5 ± 2.8 kyr after this early subtropical onset, peak interglacial conditions were reached globally, with sea level 6–13 m above present, despite weak insolation forcing. We attribute this remarkably intense climate response to an exceptionally long (~15 kyr) episode of intense poleward heat flux transport prior to the MIS 11c optimum.

The Little Ice Age (LIA; ca. 1450–1850 C.E.) is the best documented cold period of the past millennium, characterized by high-frequency volcanism, low solar activity, and high variability of Arctic sea-ice cover. Past studies of LIA Atlantic circulation changes have referenced the North Atlantic Oscillation (NAO), but recent studies have noted that LIA climate patterns appear to possess complexity not captured by an NAO analogue. Here, we present a new precipitation-sensitive stalagmite record from northern Italy that covers the past 800 years. We show that in the early LIA (1470–1610 C.E.), increased atmospheric ridging over northern Europe split the climatological westerlies away from central and northern Europe, possibly caused by concurrent Artic sea-ice reduction. With ongoing ice melting in the northern high latitudes and decreasing solar irradiance in the coming years, the early LIA may potentially serve as an analogue for European hydroclimatic conditions in the coming decades.