Organized Panel Session
Thanks to recent high-resolution reconstructions of past climate, it is now possible to compare historical events with climate change for East Asia, including the Japanese archipelago. However, for Japan, quantitative historical records from before 1500 CE are relatively scarce compared to later periods, making quantitative comparisons of changes in temperature and precipitation with those in society rather difficult.
In this paper I present a method for making such comparisons by analyzing changes in the frequency of historical references to climate-related events. As an example, I search for the term “ki,” meaning “famine,” in a database of historical records, comparing changes in the frequency of references over time with known changes in temperature and precipitation.
Specifically, I look at the relationship between climate and society during the Kamakura period (1185-1333 CE). I compare trends in the number of references to famines and other events in Kamakura ibun, a document compilation containing 35,000 documents from the Kamakura period, to actual changes in climate. Concretely, I discuss the relationship between agriculture and changes in temperature as well as the relationships among circulation or distribution of agricultural products, famine, and temperature.
In previous research on Japanese medieval history, trends in the frequency of historical references have not been viewed as reflecting actual social changes. But the present comparison shows that such statistical trends do in fact reflect social change. The paper thus provides an example of how comparing research results in two completely different fields can result in a new methodology for historical research.