Weather, agriculture, and economic stability: Reassessing the impact of temperature and precipitation on early modern Tuscany (16th–17th century)

Abstract This paper examines the impact of weather conditions on wheat production in the Florence and Siena regions in the early modern age, emphasizing the need to contextualize this influence within historical, geographical, and economic frameworks. Our quantitative findings suggest that, on average, hotter and wetter spring and summer weather conditions were beneficial for wheat yields in early modern Tuscany, though this relationship holds true only within a certain optimal range; otherwise, extreme conditions are detrimental. However, the boundaries between optimal and non-optimal conditions vary based on the historical, economic, and geographical context, ultimately determining the level of agricultural productivity. Specifically, we argue that two macro causes – primary production factors and the degree of market volatility – play a crucial role in shaping the effects of weather on agricultural outcomes. First, soil conditions, technology (broadly defined), and capital-labour ratios are the most significant determinants of agricultural productivity. Second, competitive and integrated markets, when supported by countercyclical institutions – in our case, the annona system – can mitigate the negative consequences of adverse weather by reducing the resulting volatility. Where such institutions are weak or absent, speculation (i.e., hoarding), driven by price expectations under high volatility, may arise and amplify disruptions.