Martin Bauch/Thomas Labbé: „The Dantean Anomaly 1309-1321 – Rapid Climate Change and Late Medieval Europe in a Global Perspective“ #dhmasterclass

In the context of a Junior Research Group („The Dantean Anomaly 1309-1321 – Rapid Climate Change and Late Medieval Europe in a Global Perspective“), funded by the Volkswagen Foundation as a so called Freigeist Fellowship, three sub-projects cooperate to create a dense history of a phase of rapid climate change and its socio-economic consequences. These three sub-projects focus on Northern Italy, Burgundy and Central Europe. We are about to prepare a fourth sub-project on a climate history of the Middle East in the same time.
All sub-projects will have a common ground in roughly comparable data from narrative sources for a long period (1200-1400), in which we will integrate a more detailed study of the Anomaly phase 1309-1321. This study will be based on archival material of administrative character which is available for this period in a serial form; scientific data will used to complete and correct the information from historical sources.

Visualization of the ‘Pfister-Indices’ (Image by: Martin Bauch).

Data from the long period (1200-1400) are generated from narrative sources: Textual evidence concerned with meteorological and other extreme events will be turned by comparison and source-critical interpretation in an index value (+3 to -3) for temperature and precipitation, a so called Pfister climate index (see image to the right). These indices will be available for each season.

For the project of Thomas Labbé with a geographical Focus on Burgundy and Savoy there are systematic evaluations of narrative sources mainly with the monograph of Pierre Alexandre  (Le climat en Europe au Moyen Age, 1987); this initial data base will be enhanced by research done by Thomas Labbé himself.

The project of Martin Bauch started with systematic research fort he period of 1220-1380 for the Emilia Romagna and Tuscany while he worked at the German Historicial Institute in Rome; it will be substantially enhanced by a older data collection of Emanuela Guidoboni (Bologna) from Bologna, who collected with a researcher’s crew in the 1980s data from 250 edited chronicles for the whole of Italy from 1000-1499 AD. As a resulte, 5800 separate data sets are available in georeferenced, standardized form including PDF scans of the original quotations.

Reconstruction of Northern Hemisphere temperatures during the last 2000 years. Source: IPCC Assessment Report 5 (2013), Chapter 5, Fig. 5.7.

At the end of the duration of the research group at least the quotations collected by all sub-projects might become part of already existing databases for climate history like www.tambora.org (open access) or www.euroclimhist.unibe.ch (partially restricted)

It is an unanswered question to us what else could be done with this raw data largely already available to us beyond the approaches presented above, which are almost standard procedure in climate historical research. We’ve come up with three roughly sketched ideas:

A first possibility is  to focus on the spatial dimension in the available data, which has hardly been used up to now, but which is partially already prepared by geo-referentiation. Of course it is often problematic to define how far a certain meteorological phenomenon extended in space, as you need a high density of mentionings of the same phenomenon in different sources to get a reliable idea of the area afflicted. This ‘spatialisation’ of climate historical data, maybe achievable by combination with scientific data like from dendrochronology, ice core research and geosciences (erosion, lake sediments, corals) – see the graph above -, would possibly enable a closer collaboration with with climatologists to reconstruct large scale meteorological situations in the past and possibly underlying climatic teleconnections (like El Nino/Southern Oscillation or the North Atlantic Oscillation).

A second possibility is researching the large quantity of source quotations – nothing else than a large text corpus for climate history – along semantic fields: Do medieval chroniclers talk automatically about dearth and famine when they report about drought? What semantic fields are connected by contemporary authors, on the contrary, with extreme precipitation and floodings? If such studies could be extended over long periods like two centuries, one might be able draw conclusions on a changing understanding or perception of weather phenomena: It seems reasonable that less stable meteorological conditions like e.g. wet and cool summers became the new normality during the 14^th century. But up to now, this question seemed impossible to answer.

A third possibility is a large amount of research data created in the sub projects for France and Italy from the archival documentation for Burgundy/Savoy and Bologna/Siena. For Italy these data are created from municipal authorities’ documentation on extreme events like flooding and drought, but also notes on the construction of dams, granaries, etc. Furthermore we know about the costs of imports of foodstuffs like grain and salt; partially we do have maximum prices for vital commodities. The French sub-project has more classic climate historical ‘proxy data’: crop yields and prices of wine and grain. Further information is on mortality, migration movements and destruction of infrastructure by meteorological extreme events.

Visualization of the Dantean Anomaly project’s approach to climate reconstruction (by Martin Bauch).

This research data is created in the several sub-projects in a much less homogenous way than the climate indices – and it can’t be standardized further because of the very different archival base. It is not very probable that data of the kind can be created for the Central European and the Middle East project. But the data from France and Italy has in common its high geographical resolution that allows for a detailed reconstruction of events within a few years in the small scale areas of research.
It would be intriguing to use a geographic information system (GIS) to reconstruct seasonal changes during the Dantean Anomaly and connect extreme weather with its impact in different areas and specific countermeasures and coping strategies.

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