Volcanisme global et variations climatiques de courte durée dans l’histoire romaine (Ier s. av. J.-C. - IVème s. ap. J.-C.): leçons d’une archive glaciaire (GISP2)

Abstract

Global volcanism and short-lived climatic variations during Roman history (1st century B.C. to 4th century A.D.): lessons from a glacial archive (GISP2)
The publication of ice-core records in the 1990s, and especially GISP2, recounted the main episodes of global volcanism that might have resulted in important climate-forcing. In pre-modern societies, this volcanic climate-forcing generally caused agricultural, health and social troubles (such as food shortages, epidemics, riots …). Comparing ice-core records with some episodes of roman antiquity proves fruitful. The background to the end of the Gallic war (55-51 BC) seems to be marked by an important atmospheric disturbance
which might partially account for the suddenness of some events of the Gallic rebellion of 52BC, and its most critical aspects. Some of the troubles of the late Antonine period might also be accounted for by similar volcanic events (ca. 154, ca. 162 and ca. 181 AD). However, there is no reason to link the events
of the Deserters’ war to the cataclysmic eruption of Lake Taupo, contrary to what was suggested in the 1980s. Finally, following this period, volcanic activity in the third century seems to have been more regular in a less favourable climatic era: did these factors contribute to the troubles of the Empire at that critical time? As it is, the existence in the 260s of a disturbance of at least equal importance as that of the Antonine period, has been attested. On the contrary, the fourth century after 332 AD, bears no trace of any major eruption: no volcanic forcing disturbed imperial recovery then.