How to Write and Think about Political, Social, and Economic History in Dialogue with Climatic and Environmental Data: A Case Study in the Age of Charlemagne, 740-820

Over the past two decades, the growing availability of palaeo-climatic data has opened up new opportunities for cross-fertilisation and comparison between natural and social sciences. The parallel history of climate and the environment is often undertaken in a holistic manner, assuming simple and direct causalities between the climate and social change. Faced with the findings of research into historic climates, the historian must question the nature of the data and their specific conditions of gathering, validity and environment, as well as the methods and objectives of modelling. Comparing paleoclimatic data and primary sources requires taking into account their specific limitations and finding a common scale of observation.This paper will discuss a historical case study conducted using climate data and documentary sources from the age of Charlemagne (740-820 AD), a time interval of 80 years that is compatible with the heuristic requirements of both disciplines. Approaching meteorological events by magnitude makes it possible to analyse the conditions under which the weather was observed. Textual witnesses are influenced by the political context and by religious cosmologies, but also by environmental conditions and regional geo-climates, as shown by a corpus constituted from Frankish, Irish, Early English, Spanish Arab, Byzantine and Syriac Christian sources. What emerges is a rich picture of under what circumstances and for what reasons witnesses speak or remain silent, and which meteorological or ecological phenomena have the most meaning and significance for them. There were, in these years, four periods of crisis: a winter marked by extreme temperatures (763-764), and three periods described by Carolingian sources as severe famines ("great hungers"): a regional crisis in the Rhine Valley (779), multi-annual and multi-regional crisis phenomena between 791 and 794 in Francia and Italy, and a prolonged period of difficult climatic conditions between 800 and 824 in northwestern Europe, accompanied by a rinderpest pandemic in 810-811. This multifactorial approach shows that the climatic parameter never acted alone in the perception and in the economic and social repercussions of environmental parameters. Witnesses were influenced in their assessment of the critical nature of a crisis by other elements of a religious, political, military nature. While the fear of hazards and their cosmological significance haunted early medieval European societies, they did not remain passive and demonstrated political creativity and social resilience in dealing with the challenges of the climate. The historical approach thus makes it possible to stress the spatial and temporal complexity of the interactions between climate, environment, and social ecosystems, all of which argue against a holistic approach that tends to confuse coincidences, correlations and causalities, underestimates social and agro-ecological feedbacks, and makes climate an absolute instance of determinism. At a time when contemporary societies are plagued by environmental anxiety, environmental history offers a lesson both in caution and optimism.This is the Keynote Lecture delivered at IMC 2021 Climates