Beyond one-way determinism: San Frediano’s miracle and climate change in Central and Northern Italy in late antiquity

Abstract

Integrating palaeoclimatological proxies and historical records, which is necessary to achieve a more complete understanding of climate impacts on past societies, is a challenging task, often leading to unsatisfactory and even contradictory conclusions. This has until recently been the case for Italy, the heart of the Roman Empire, during the transition between Antiquity and the Middle Ages. In this paper, we present new high-resolution speleothem data from the Apuan Alps (Central Italy). The data document a period of very wet conditions in the sixth c. AD, probably related to synoptic atmospheric conditions similar to a negative phase of the North Atlantic Oscillation. For this century, there also exist a significant number of historical records of extreme hydroclimatic events, previously discarded as anecdotal. We show that this varied evidence reflects the increased frequency of floods and extreme rainfall events in Central and Northern Italy at the time. Moreover, we also show that these unusual hydroclimatic conditions overlapped with the increased presence of “water miracles” in Italian hagiographical accounts and social imagination. The miracles, performed by local Church leaders, strengthened the already growing authority of holy bishops and monks in Italian society during the crucial centuries that followed the “Fall of the Roman Empire”. Thus, the combination of natural and historical data allows us to show the degree to which the impact of climate variability on historical societies is determined not by the nature of the climatic phenomena per se, but by the culture and the structure of the society that experienced it.

Insight into summer drought in southern Italy: palaeohydrological evolution of Lake Pergusa (Sicily) in the last 6700 years

“…This period coincides with data from a speleothem δ 18 O record from the Apuan Alps in Northern Tuscany, which show a prominent wetter interval during the 6th century ad (Fig. 9; Zanchetta et al ., 2021) and is again associated with increasing flood events evidenced from historical sources also in northern Italy (Zanchetta et al ., 2021, and references therein). It has been suggested that generally wetter conditions during this period were recognizable in most of the eastern Mediterranean area (e.g.…”

“…Izedebski et al, 2016). According to Zanchetta et al (2021) this would correspond to major advection of vapour masses from the Atlantic, and to increasing cyclogenesis over the Mediterranean related to an increase of advection of vapour from Westerlies during winter. This is in agreement with the North Atlantic Oscillation (NAO) negative mode (Fig.…”

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

“…Indeed, the primary role of the amount effect controlling δ 18 O sp in speleothems of the central and western Mediterranean realm has been indicated by other Mediterranean studies, for example along the Spanish Mediterranean borderlands 39 and islands 70 , Croatia 71 and Macedonia 72 . In Italy, the same effect dominates δ 18 O sp in the northern and central portion of the Peninsula 32,67,[73][74][75][76][77] and Sardinia 45,66 . Rainfall amount was also driving δ 18 O sp in the above-mentioned PC stalagmite 36 in a cave ~40 km NW with respect to Sant'Angelo (Supplementary Fig.…”

Riverbed, Banks and Beyond: An Examination of Roman Infrastructure and Interventions in Response to Hydrological Risk in the Po–venetian Plain

“…These are complemented by more targeted studies that can reconstruct local climate in detail.19 The narrative of the Roman Climatic Optimum has been strongly challenged byHaldon et al, 2018. 20 Speleothem analysis from Renella cave in the Apuan Alps also points to a significant increase in flooding in northern and central Italy during the sixth century AD(Zanchetta et al, 2021).21 The floods here are considered exceptional events, as opposed to the smaller annual floods common in the region.22 A similar outcome can be seen at the fort site of Oedenburg in France, where the lowest-lying parts of the adjacent vicus were abandoned in the fourth century, probably as a result of the rising water table and subsequent increased risk of flooding(Ollive, 2007: 651-2). See alsoOllive et al, 2006Ollive et al, , 2008…”

“… 20 Speleothem analysis from Renella cave in the Apuan Alps also points to a significant increase in flooding in northern and central Italy during the sixth century AD (Zanchetta et al ., 2021). …”