A week ago I returned from what was, surprisingly, my first trip to Germany. This year the European Society for Environmental History convened its biannual conference in Munich, a city I’ll remember for its beautiful architecture, sensible public transit and delicious beer. No fewer than fifteen climate history panels were part of the conference, and despite my best attempts I couldn't attend them all. Still, I decided to share some of what I learned (or remembered) while listening to papers that were good enough to keep me from exploring Munich. Note that for the purposes of this little article, the terms “climate history” and “historical climatology” are synonymous.
1. Climate history must be inclusive to be effective.
There is only limited value in mining one kind of documentary source for evidence of past weather and, in turn, past climate change. Of course, the value of such work fluctuates with the source under investigation: registers of past events called chronicles are notoriously prone to exaggeration, for example, while ship logbooks provide standardized, easily quantifiable and remarkably reliable weather observations. Still, a reconstruction of past climate that makes any claim to accuracy must, where possible, employ a wide variety of documentary evidence compiled by many authors. These reconstructions are strengthened when meteorological information contained in some documentary sources can be verified using the data contained in other documents. They gain even more credibility alongside scientific evidence like model simulations, or statistics developed using natural archives (ice cores or tree rings, for example). Good climatic reconstructions are necessarily interdisciplinary, and we should think carefully about what we are really saying when we discuss observations written by a single author, in a single source. Are we reconstructing the climate of a vast region across the decades, or are we engaging in literary criticism?
If interdisciplinary work is essential to historical climatology, interactions between sub-disciplines are just as important. Climate history is often considered a sub-discipline of environmental history, which, in turn, is one genre in the broader field of history. Agricultural history, forest history and energy history are all among the sub-disciplines that together constitute environmental history. Like climate history, they lose significance when divorced from one another. Reconstructions of past climates are fascinating, but historians can also incorporate the many different sub-disciplines and genres of their profession to do something scientists can’t: weave the history of climate into the history of humanity. The narratives we get can be as valuable as the models developed by scientists as we struggle to understand our plight on a warming planet.
2. We're only scratching the surface of relevant documentary evidence.
Chronicles and weather diaries have long formed the backbone of the documentary evidence used to reconstruct past climates. Questions of interpretation hound both sources, however, and these days, correspondence and ship logbooks are increasingly in vogue. In Munich I heard scholars like Rudolf Brázdil describe how correspondence related to the collection of taxes can yield strikingly detailed climatic reconstructions. Tax records can be placed alongside court documents, toll accounts and maintenance registers as largely quantitative sources that can yield rich climatic data if interpreted using qualitative evidence. New sources – and new methods of source interpretation - can provide data about wind patterns, hailstorms, and other previously unexamined meteorological conditions, deepening our understanding of climate change.
3. We need new ways of conceptualizing the relationship between climate change and human history.
Fernand Braudel, perhaps the greatest historian of the twentieth century, introduced a revolutionary way of conceptualizing time. According to his notion of “total history,” different kinds of historical change transpire differently across time and space. Environmental or economic transformation at a vast scale spanned the centuries, yet the historical “event” was immediate. Understanding the past from this perspective allowed him to gather the entire Mediterranean world into a single narrative using the huge, lumbering structures of history.
The problem for historical climatologists – and indeed, all environmental historians – is that Braudel was wrong. Interdisciplinary research has revealed that many historical structures can be brittle; they can break quickly with immediate yet regionally specific ramifications. For example, climate change influenced by volcanic eruptions and the subsequent expansion of polar ice could alter prevailing weather patterns over the North Sea in one cruel winter. However, the same processes behind routinely cold winters in northern Europe could bring not frost but rather drought to the Mediterranean.
So different kinds of historical change can occur across many scales of time and space, and that complicates our attempt to conceptualize connections between past environments and historical events. Human history cannot be modeled – we simply lack all of the necessary variables – but in recent years environmental historians have made great progress going beyond the problematic concepts like footprint metaphor or social metabolism in their efforts to conceptualize the connections between nature and society. In this effort historical climatologists lag behind their peers, and for that reason climate histories can devolve into lists in which weather events likely stimulated by a climatic shift cause environmental changes that contribute to one event after another in the history of a particular region. Historians need to work with colleagues across many disciplines to develop ways of understanding relationships between climate, weather and human history. These ways of understanding might not completely explain the past, but they might help us conceive of historical change more clearly, with insights applicable for our future on a warming planet.